Journal articles: 'Absolute fecundity'

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Diakov, Yury P. "Fecundity of the Far-Eastern flatfishes Pleuronectiformes. 1. General characterization of fecundity of Pleuronectiformes in the northern part of the Pacific Ocean." Izvestiya TINRO 188, no. 1 (March 30, 2017): 54–88. http://dx.doi.org/10.26428/1606-9919-2017-188-54-88.

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Cited and archive data on fecundity of 31 flatfish species are generalized for the North Pacific. General characterization of the fecundity is presented and correlation between absolute individual fecundity of the females and their body length or age is analyzed and formalized in equation form. Spatial variability of fecundity is described for different species: pacific halibut and starry flounder have the highest absolute fecundity in the eastern Bering Sea and Okhotsk Sea, greenland halibut, yellowfin sole, alaska plaice, sakhalin flounder, longhead dab, and flathead sole - in the Okhotsk Sea, northern rock sole - in the waters at East and West Kamchatka. kamchatka flounder - in the Bering Sea, arrowtooth flounder - in the Pacific waters at North America. So, the Okhotsk Sea is the area where the absolute fecundity of majority wide-spread flatfish species can reach the maximal level. However, the maximal fecundity of longsnouted flounder is higher in the Japan Sea than in the Okhotsk Sea.

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Diakov, Yury P. "Fecundity of the Far-Eastern flatfishes Pleuronectiformes. 2. Comparative taxonomic analysis: fecundity, abundance and distribution of the species." Izvestiya TINRO 188, no. 1 (March 30, 2017): 89–114. http://dx.doi.org/10.26428/1606-9919-2017-188-89-114.

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Comparative analysis is made for absolute, species-specific and total fecundity of 31 flatfish species in the North Pacific from North America to the Japan Sea. Normally the individuals of larger size have higher fecundity. Similarity between the species by fecundity dynamics in dependence on body length and age is evaluated. Significance of the absolute fecundity for abundance or distribution of the species is discussed. Generally, the species with medium or high fecundity are more abundant than those with low number of eggs. The widest distribution is intrinsic for flatfish species with medium length of the early pelagic stage of their life.

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Hossian, Shajjad, Sudip Bhattacharya, Md Atiar Rahman, Rashedul Islam, Rabeya Yesmin, Salina Akhter Sume, and Md Moniruzzaman. "Fecundity estimation of Indian Potasi, Neotropius atherinoides in Bangladesh." Research in Agriculture Livestock and Fisheries 6, no. 3 (January 1, 2020): 421–29. http://dx.doi.org/10.3329/ralf.v6i3.44808.

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Fecundity estimation has obvious significance in aquaculture, since the size of brood stock, amount of rearing facilities and necessity of other equipment’s are dependent on fecundity. The study has been conducted on fecundity estimation of Indian potasi, Neotropius atherinoides, based on 202 females collected from the Kangsha River flowing through Netrokona district during the period from January to June 2013. The standard length (SL) range of female were 47-66, 50-64, 57-68, 50-66, 56-66 and 60-76 mm and range of body weight were 1.07-3.56, 1.23-3.35, 2.36-3.81, 1.69-4.31, 2.33-5.59 and 3.18-5.14 g in January, February, March, April, May and June, respectively. The mean Gonado somatic indices (GSI) were very low from January to March but these were abruptly high during subsequent three months. Based on mean GSI the spawning season of this species was assumed from April to June over the study period. Scatter plot of standard length with corresponding GSI revealed that the minimum length of mature female was 50 mm SL. Egg diameter frequency distribution of a mature ovary showed almost only one major mode of egg size suggested that the fish is a single spawner, and summation of eggs in that mode was regarded as the fecundity of a female Indian potasi. The regression equation of the relationship between standard length and fecundity was as, Fecundity = 0.0017 SL 3.55. The relative fecundity and the absolute fecundity of a fish having SL of 62 mm was 1477 per g and 3921, respectively based on F-SL relationship. The relationship between body weight and fecundity was as, Fecundity = 1371.3 BW-650.8. The absolute fecundity of a fish having BW of 3.51 g was 4162 respectively based F-BW relationship. The relationship between ovary weight and fecundity was as, Fecundity = 6244.3 OW + 967.52. The absolute fecundity of a fish having ovary weight of 3.51 g was 7211 based F-OW relationship. The correlation coefficient of all above analyses were very high (>0.755) attributing that standard length, body weight and gonad weight were highly positively correlated with fecundity of Indian Potasi, Neotropius atherinoides. Res. Agric., Livest. Fish.6(3): 421-429, December 2019

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Baki, Hakan, Eyüp Çakmak, Birol Baki, and Cemil Altundaş. "III. Nesil (F3) Karadeniz Alabalığı (Salmo trutta labrax Pallas, 1814) Anaç Ağırlığı ve Kuluçka Verimi İlişkisi." Turkish Journal of Agriculture - Food Science and Technology 3, no. 7 (June 11, 2015): 550. http://dx.doi.org/10.24925/turjaf.v3i7.550-555.382.

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In this study, this was the aimed to determine the reproduction and hatching yields in different weight groups in hatchery origin rootstocks (F3) Black Sea trout (Salmo trutta labrax Pallas, 1814). In this study, the female fishes which produced from natural rootstock were used average weight 1437±134.6 g (Group I) 2737±210.2 g (Group II) and 3785±162.3 g (Group III). After the stripping process; according to the groups, were determined respectively eggs absolute fecundity (number of eggs/broodfish) is average 2353±205, 5361±506, 6603±491, relative fecundity (number of eggs/kg)) is average1687±166, 1968±194, 1744±114. The egg diameter (mm) 4.89±0.16, 5.28±0.07, 5.31±0.06 egg weight (mg) 77±6, 90±4, 96±3 groups I., II. and III. respectively was calculated. The fertilization ratio (%) 95.49±1.23, 96.49±1.14, 98.39±0.52, browse rate (%) 79.97±5.36, 84.20±5.23, 94.70±1.50, has been identified. The output rate (%) 60.57±7.86, 67.66±6.42, 84.83±3.09, the hatchery efficiency (%) 58.14±7.95, 69.77±6.25, 83.51±3.29 was found. relative fecundity average value 168±160, 1968±194, 1744±114.The existence of relationship among the weight of the brood-stock, absolute fecundity (0.0198, 0.0012, 0.3499), and relative egg fecundity (0.3415, 0.0494, 0.00) was tested by regression analysis and consequently the difference between groups were significant. This was determined that between fish weight and absolute fecundity relationship is weak directly proportional for each group, between fish weight and relative fecundity is weak inversely proportional in Group I and II, the Group III is weak for directly proportional.

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Zhang, Fan, Kevin B. Reid, and Thomas D. Nudds. "Counterintuitive patterns of spawning stock age structure and recruitment in Lake Erie yellow perch (Perca flavescens)." Canadian Journal of Fisheries and Aquatic Sciences 72, no. 10 (October 2015): 1494–502. http://dx.doi.org/10.1139/cjfas-2014-0489.

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Older spawning fish were often observed to contribute more recruits to harvested stocks than younger fish. However, effects of spawning stock age structure on recruitment were not universally detected. We tested effects of age-dependent absolute fecundity, age-dependent relative fecundity, and age-related maternal effects on recruitment by Lake Erie yellow perch (Perca flavescens). No effects of age-dependent absolute fecundity and age-dependent relative fecundity, nor positive age-related maternal effects, were detected at multidecadal or finer temporal scales of analysis, between 1975 and 2013. Instead, we found evidence of negative age-related maternal effects, of spatially and temporally varying strength; older cohorts in the spawning stock were sometimes associated with lower offspring survival. Such counterintuitive results imply that biotic and abiotic factors, such as interspecific predation, during larval and juvenile life stages might strongly affect recruitment of Lake Erie yellow perch.

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Kyritsi, Stavroula, and Antonis K. Kokkinakis. "Age, Growth, Reproduction and Fecundity of Roach Rutilus rutilus from Volvi Lake, Northern Greece." Turkish Journal of Fisheries and Aquatic Sciences 20, no. 10 (July 7, 2020): 717–26. http://dx.doi.org/10.4194/1303-2712-v20_10_01.

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The roach, Rutilus rutilus, is a Cyprinid which is widely distributed throughout freshwater systems in Europe. It is one of the most abundant and important commercial fish species in Greece. Age, growth, reproduction and fecundity of roach were studied in Lake Volvi from 1997-1998 females had higher growth in length (L∞=277.18 mm, k=0.097) than adult males (L∞=185.60 mm, k=0.148). All males older than one year and larger than 70 mm, and all females older than two years and larger than 80 mm were sexually mature. The breeding period spanned from the end of March till mid April. Fecundity ranged from 2,036 to 31,653 eggs (mean 8,102 eggs) and relative fecundity from 76.06 to 333.94 eggs/g (mean 186.78 eggs/g). Diameter of eggs were 1.3 ± 0.07 mm and weighted 0.0011 ± 0.0002 g . The weight of eggs were independent of length and age of individuals (P>0.05), however, there was a significant relationship between weight and egg diameter (P<0.05). Absolute fecundity depended on length, weight and age of the females. The relationship between absolute fecundity and length were less obvious in the case of relative fecundity and egg size. Estimated growth was at the lower end when compared with other studies conducted elsewhere.

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Cognato, Diego de Paula, and Clarice Bernhardt Fialho. "Reproductive biology of a population of Gymnotus aff.carapo (Teleostei: Gymnotidae) from southern Brazil." Neotropical Ichthyology 4, no. 3 (September 2006): 339–48. http://dx.doi.org/10.1590/s1679-62252006000300005.

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The reproductive period and its relation with somatic and abiotic factors, the relative and absolute fecundity, spawning type, length of first maturation and sex ratio is describe for Gymnotus aff.carapo from a small lake at Itapuã State Park, Rio Grande do Sul, Brazil. Gymnotus aff. carapo presents a relatively long reproductive cycle extending from November/2003 to March/2004. Decreases in water conductivity and increases in dissolved oxygen are correlated with increased gonadal development in males. In females, seasonal increases in temperature and photoperiod and decreases in dissolved oxygen are correlated with increased gonadal development. The mean absolute fecundity was 915.3 oocytes, and mean relative fecundity 0.20 oocytes/mg body weight. Egg size distributions indicate multiple spawning. The size of first maturation was 141 mm in females and 146 mm in males. The sex ratio was 1:1, with a male bias only in smaller size classes.

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Cengiz, Özgür. "Some reproductive characteristics of the blotched picarel Spicara maena (Perciformes: Centracanthidae) from Saros Bay, Northern Aegean Sea, Turkey." Revista de Biología Marina y Oceanografía 54, no. 2 (September 13, 2019): 174. http://dx.doi.org/10.22370/rbmo.2019.54.2.1905.

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This study was carried out, monthly, in the Saros Bay (Northern Aegean Sea, Turkey) between January 2015 and December 2015. The gonadosomatic index (GSI) and absolute fecundity (Fa) of the blotched picarel (Spicara maena) were analyzed . The present study contributes to the reproductive biology of S. maena by reporting the first data about the fecundity of the species for the Aegean Sea

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Jabed, Md Naimuddin, Mohammad Amzad Hossain, Sohel Mian, Muhammad Anamul Kabir, Sabuj Kanti Mazumder, and Mohammed Mahbub Iqbal. "Some Aspects of Reproduction in Long Whiskered Catfish, Sperata aor (Hamilton 1822), from North-East Bangladesh." Aquaculture Studies 21, no. 2 (February 8, 2021): 47–54. http://dx.doi.org/10.4194/2618-6381-v21_2_01.

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Different reproductive aspects such as sexual maturity, spawning, gonadosomatic index, fecundity, and histological changes in gonads of captive reared Sperata aor were investigated for a period of one year. Male and female fish were identified by based on morphological characteristics. The spawning season was found to be extended from May-August. Gonadosomatic index reaches maximum in August and lowest in September. Absolute fecundity varied from 59255 to 70586 with an average value of 64920. Absolute fecundity had been reported to be increased with total length, body weight. Histological study of ovary of S. aor indicated the presence of four developmental stages viz, early perinucleolar s oocytes, late perinucleolar oocytes, yolk vesicle stage and yolk granular stage. Findings reveal that, S. aor has group asynchronous manner of ovarian growth and used to spawn numerous times in a year under favorable environmental conditions. The testes histology represents the presence of spermatocyte, spermatid, and spermatozoa. This species builds nests during breeding season and fries are found within the nests.

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Bhendarkar, Mukesh P., Rajiv H. Rathod, Harshavardhan D. Joshi, and Upasana Sahoo. "Study on the Fecundity and Gonado somatic index of Rastrelliger kanagurta (Cuvier, 1817) of southern coast of Maharashtra, India." Journal of Applied and Natural Science 10, no. 1 (March 1, 2018): 107–10. http://dx.doi.org/10.31018/jans.v10i1.1588.

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Investigation of fecundity and gonado somatic index (GSI) of Rastrelliger kanagurta were carried out from March 2011 to February 2012. Fecundity was determined at different length, weight and ovary ranges of different individual fishes. Study revealed that at 5% significant level significant average absolute fecundity was found to be 1,08,266 and relative fecundity ranged from 407 to 1499. The number of ova generally increased with increase in length and weight. However, variations in fecundity with respect to length and weight were also noticed. The gonado-somatic index (GSI) was calculated for each individual fish (592 numbers) and was averaged for each month. The average GSI values were plotted against each month to analysed monthly variations. GSI showed wide variations between sex and it was highest for both males and females during the month of April and September, showing occurrence of more ripe individuals. Analysis of regression showed that there were significant relationship between the fecundity with the fish length, body weight and ovary weight.

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German, Alexander Vladimirovich, and Tatiana Aleksandrovna Suvorova. "Rate of sexual maturation and fecundity of the roach Rutilus rutilus (L.) of the Volga reach of the Rybinsk reservoir." Rybovodstvo i rybnoe hozjajstvo (Fish Breeding and Fisheries), no. 9 (September 1, 2020): 13–22. http://dx.doi.org/10.33920/sel-09-2009-02.

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Climate warming and the introduction of a new mass species of clam Dreissena bugensis can potentially lead to changes in the reproductive capacity of benthic fish species living in the upper Volga reservoirs. The age of puberty, the structure of the spawning stock, and fecundity are the main indicators of reproduction that determine, together with indicators such as the survival of young fish and the degree of fishing load, the relative number of species in the ichthyofauna. The purpose of this work was to study the size and age of the onset of puberty and the dynamics of fecundity of roach Rutilus rutilus in the Volga ples of the Rybinsk reservoir. Determination of individual absolute fecundity was performed by counting eggs in fresh gonads, without the use of fixation. The age of fish was determined by scales, and vertebrae and operculum were used as additional recording structures. As a result, it is shown that the beginning of sexual maturation of female roach occurs when reaching the age of 3+ and a length of more than 9 cm. Late maturing females were 4+ years old and over 18 cm long. The beginning of sexual maturation of males could not be determined. The smallest males in the catches, 7–8 cm long, were all sexually Mature. The maximum age of fish reached 12+ years with a length of no more than 32 cm. Individual absolute fertility ranged from 1,75 to 178,46 thousand eggs. The value of relative fertility ranged from 79 to 308, with an average of 171 eggs/g. The result concluded that high absolute and relative fecundity of roach and dynamic changes of fertility in terms of increase in average water temperature and absolute improvement of fodder after the invasion of Dreissena bugensis, may indicate the attainment of specific limit reproductive capacity of this species.

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Mikhailova, Oksana G., and Pavel Yu Ivanov. "Fecundity of northern shrimp Pandalus borealis dwelling at the west coast of Kamchatka." Izvestiya TINRO 182, no. 3 (September 30, 2015): 81–87. http://dx.doi.org/10.26428/1606-9919-2015-182-81-87.

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Fecundity of northern shrimp Pandalus borealis is investigated for the first time on the data collected from the depth 200-400 m near the coast of West Kamchatka in 2013-2014. The absolute and relative individual fecundity are determined, their relationship with size and age of the shrimp is analyzed. The individual fertility of females changes in limits of 1395-4648 eggs, with average number in the laying 2799 ± 190 eggs. The maximum fecundity is noted for females at the age of 7+. Losses of eggs for the northern shrimp at the west coast of Kamchatka don’t exceed 12 %.

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Manzer, J. I., and I. Miki. "Fecundity and Egg Retention of Some Sockeye Salmon (Oncorhynchus nerka) Stocks in British Columbia." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 8 (August 1, 1986): 1643–55. http://dx.doi.org/10.1139/f86-203.

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The fecundity and egg retention of anadromous female sockeye salmon (Oncorhynchus nerka) collected during 1971–82 from several stocks in British Columbia undergoing controlled fertilization to enhance adult sockeye production were examined. The relationship between egg number and postorbital–hypural length based on 863 females representing 14 stocks was not consistent between all age-types, stocks, and years, probably because of inadequate sample size in some instances. Combined samples, however, revealed a significant positive relationship between postorbital–hypural length and egg number for age 1.2, 1.3, and 2.2 females. Mean absolute fecundity for the respective age-types was 3218, 4125, and 3544 eggs. For samples of 10 or more females, significant stock and annual differences were detected when individual mean absolute fecundity was adjusted to a postorbital–hypural length of 447 mm, but not for females of different age. A comparison of mean fecundities for coastal stocks with historical data for interior British Columbia stocks suggests that coastal stocks are 18% more fecund than interior stocks. Possible causal mechanisms for this regional difference are hypothesized. Examination of 796 carcasses (representing five stocks) for egg retention revealed a range from totally spawned to totally unspawned females, with 56% of the carcasses containing 20 eggs or less and 68% containing 50 eggs or less. The mean egg retention based on all samples combined was estimated to be 6.5% of the mean individual fecundity. This value was reduced to 3.9% when stock means were averaged.

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VAN DER MOLEN, SILVINA, and JESÚS MATALLANAS. "Reproductive biology of female Antarctic spiny plunderfish Harpagifer spinosus (Notothenioidei: Harpagiferidae), from Îles Crozet." Antarctic Science 16, no. 2 (June 2004): 99–105. http://dx.doi.org/10.1017/s0954102004001865.

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On the basis of histological examination, we present the first description of oogenesis in H. spinosus. Eight stages of oocyte development were identified using morphological and histochemical criteria. The development of the oocytes is synchronous, and two clutches grow simultaneously in the ovary. Spawning takes place during the end of summer and the beginning of autumn. Absolute fecundity is low, ranging from 787 to 1504 oocytes. The low fecundity is probably related to parental behaviour. Our data indicate that the features of the reproductive biology of H. spinosus, in spite of its unusual environment, are similar to those observed in other teleost fish.

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Allain, V. "Fecundity of the deep-sea fish in the north-east atlantic Alepocephalus bairdii (Pisces: Alepocephalidae)." Journal of the Marine Biological Association of the United Kingdom 79, no. 4 (August 1999): 765–67. http://dx.doi.org/10.1017/s0025315498000952.

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Alepocephalus bairdii is a deep sea fish caught but discarded by semi-industrial fisheries from the north-east Atlantic Ocean. Reproductive features were investigated on 448 females of 29–93 cm standard length (SL) captured over 2 y (December 1995–December 1997) at 800–1280 m off the west coast of the British Isles. The first maturity of females was determined at L50=55 cm SL. A well-defined spawning period could not be determined in this species; a batch spawner characterized by an indeterminate annual fecundity. Absolute batch fecundity was estimated between 458 and 7049 oocytes per female 63–88 cm SL.

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Subba, Suren, Vinod Kumar Mahaseth, Bharat Raj Subba, and Shyam Narayan Labh. "Fecundity, histomorphology of the ovary and size at first maturity of Neolissochilus hexagonolepis (McClelland) in Tamor River, Nepal." Journal of Applied and Natural Science 12, no. 3 (September 7, 2020): 401–10. http://dx.doi.org/10.31018/jans.v12i3.2338.

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Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p<0.001) than other body metrics. The results showed that female individuals of N. hexagonolepis attained the first sexual maturity at TL 32.9 cm. N. hexagonolepis exhibited a protracted breeding period with its ovaries passing through six different stages of maturation. The finding of the present study may serve as a protocol for fishery biologists and managers to promulgate adequate regulations for continual fishery management in the River Tamor, Nepal.

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Kamilov, B., M. Yuldashov, U. Soatov, and M. Nazarov. "Variability of growth, maturation and fecundity of gibel carp (carassius gibelio) in different environments of Uzbekistan." E3S Web of Conferences 258 (2021): 04034. http://dx.doi.org/10.1051/e3sconf/202125804034.

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The goal of present study was to examine gibel carp, Carassius gibelio (Bloch, 1782) growth, maturation, fecundity and ripe eggs size under pond fish culture conditions and conditions of natural water bodies of the River Syrdarya, Uzbekistan. Gibel carp originally came from the River Amur (Russia), it was introduced to Uzbekistan in 1950s. Recently, it is wide spread species in local ichthyofauna. Females matured for the first time at age 2 years: in ponds in 8-10 cm in standard length, in the river in 18-20 cm. The GSI increased to spawning up to 2.9 – 25%. In fish farm ponds absolute fecundity was 1,4 – 51,300 eggs, in the River Syrdarya - 9,2 – 91,400 eggs. Relative fecundity in all populations was 21 – 590 eggs/g in weight of gutted fish. In April, there were two peaks of ripe and yolk eggs size: 1st - 0.89 – 1.69 mm, 2nd – 0.69-0.9 mm.

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NDIAYE, Ismaïla, Alassane SARR, Alioune FAYE, Modou THIAW, Malick DIOUF, Kamarel BA, Waly NDIAYE, Najih LAZAR, and Omar Thiom THIAW. "Reproductive Biology of Round Sardinella (Sardinella Aurita) (Valenciennes, 1847) in Senegalese Coastal Waters." Journal of Biology and Life Science 9, no. 1 (January 25, 2018): 31. http://dx.doi.org/10.5296/jbls.v9i1.12222.

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In this study, a total of 1068 specimens Sardinella aurita of which 553 females and 515 males were examined. The objectif of this study was to determine the reproductive parameters of Sardinella aurita. The sex ratio was significantly in favor of females (55%). The size at first sexual maturity was estimated at 18.9 cm for females and 18.0 cm for males. The monthly variation of sexual maturity stages and gonado-somatic index (GSI) allowed to locate the reproduction periods from February to June and from September to December. The mean absolute fecundity was estimated at 110.794 ± 7582 oocytes whereas relative fecundity was about 422 ± 26 oocytes per gram of female.

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Casimiro, Armando César Rodrigues, Diego Azevedo Zoccal Garcia, Fernanda Simões de Almeida, and Mário Luís Orsi. "Reproductive Aspects of Moenkhausia intermedia Eigenmann, 1908 (Pisces, Characidae) in the Upper Paraná River Basin, Brazil." ISRN Zoology 2011 (June 30, 2011): 1–8. http://dx.doi.org/10.5402/2011/802794.

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The aim of this work was to determine the reproductive tactic of the population of Moenkhausia intermedia, inhabiting the Capivara Reservoir, lower Paranapanema River. Four different stretches of the reservoir were selected, and sampling was carried out quarterly, in the period from 2001 to 2004. Fish were captured utilizing gill nets, cast nets, and seine nets. Later, fish were identified and measured and had their sex identified. Here we describe sex proportion, standard length at first maturation (), site and period of spawning, fecundity and type of spawning. The population showed an effective reproductive activity in the area, with the number of females higher than males and corresponding to 6,1 cm and 5,5 cm, respectively. A greater intensity of spawning occurred in the warmest months. Reproductive activity was identified in all stretches studied, and the absolute fecundity average was 9611 oocytes per gonad, and the mean relative fecundity corresponded to 1065 oocytes/grams.

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La Mesa, Mario, Vincenzo Caputo, Riccardo Rampa, and Joseph T. Eastman. "Gametogenesis in the Antarctic plunderfishes Artedidraco lönnbergi and Artedidraco skottsbergi (Pisces: Artedidraconidae) from the Ross Sea." Antarctic Science 18, no. 2 (June 2006): 183–90. http://dx.doi.org/10.1017/s0954102006000216.

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The Antarctic plunderfishes Artedidraco lönnbergi and A. skottsbergi are small, bottom dwelling species inhabiting the continental shelf of the High Antarctic Zone. During cruise 97–9 of the US RV Nathaniel Palmer during the summer in the south-western Ross Sea, samples of both species were collected by means of bottom trawling. On the basis of macroscopic and histological analysis, we present the first data on the reproductive characteristics of these two plunderfishes, including gametogenesis, spawning period and absolute fecundity. Histologically, we found immature (stage I and II) and mature (stage V) females in both species, whereas developing females (stage III) were found only in A. skottsbergi. All examined male specimens of A. skottsbergi were in the final stage of spermatogenesis (stage III), whereas male A. lönnbergi were immature (stage I), mature (stage IV) and post-reproductive (stage V) individuals. In both species, spawning takes place in summer during December and January. Absolute fecundity was very low, with less than 100 and 200 oocytes in A. lönnbergi and A. skottsbergi, respectively. These data are compared with those reported in literature for other artedidraconids.

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Kuhn, Kristen L., Thomas J. Near, H. William Detrich, and Joseph T. Eastman. "Biology of the Antarctic dragonfishVomeridens infuscipinnis(Notothenioidei: Bathydraconidae)." Antarctic Science 23, no. 1 (August 20, 2010): 18–26. http://dx.doi.org/10.1017/s095410201000060x.

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AbstractNineteen specimens of the rare dragonfishVomeridens infuscipinniswere evaluated for meristic counts, morphometric measurements, vomerine teeth and the supratemporal canal, anatomical and histological observations of bone, cartilage and lipid, diet, and reproductive status. Seven individuals were measured for buoyancy. All specimens had small vomerine teeth that varied in number. There was also variability in the arrangement of the supratemporal pores and canals.Vomeridenspossess a body with little bone and considerable amounts of cartilage and lipid. A mean percentage buoyancy of 1.61% indicated thatVomeridensis nearly neutrally buoyant. Inferences from measurements of buoyancy and from morphological data suggest thatVomeridenslives in an epibenthic water column habitat at 400–900 m. Facilitated by its reduced body density,Vomeridensare likely to forage in the water column by hovering above the substrate. The stomach contents consisted of krill (Euphausia superba), some as large as 46–50 mm.The absolute and relative fecundity in seven female was 1576–2296 oocytes (mean 1889) and 21.3–28.9 oocytes g-1body weight (mean 25.3), respectively. The reproductive effort in terms of egg diameter, GSI, and absolute and relative fecundity is similar to that for other bathydraconids.

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Gonçalves, Taís K., Marco A. Azevedo, Luiz R. Malabarba, and Clarice B. Fialho. "Reproductive biology and development of sexually dimorphic structures in Aphyocharax anisitsi (Ostariophysi: Characidae)." Neotropical Ichthyology 3, no. 3 (September 2005): 433–38. http://dx.doi.org/10.1590/s1679-62252005000300012.

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The reproductive period of Aphyocharax anisitsi is described through the analysis of specimens collected monthly from April 2001 to March 2002 in the arroio do Salso (3022'27"S, 5502'06"W), Rosário do Sul, Rio Grande do Sul, Brazil. The monthly variation of the Gonadosomatic Index mean (GSI) of both males and females allowed the recognition of a defined seasonal reproductive period occurring between September and February, showing a positive correlation with temperature and day-length. Absolute fecundity was 344.8 oocytes and relative fecundity 0.68 oocytes per mg of body weight. Absolute fecundity was correlated with standard length and total body weight. It was possible to identify two categories of males through the analysis of the number of rays bearing hooks on the anal fin: those with few or no rays bearing hooks identified as young males hatched in the last reproductive season, and those with a higher number of anal-fin rays bearing hooks identified as males that had already reproduced once or that are maturing and participating in their first reproductive period. Once developed, anal-fin rays are maintained permanently. A positive correlation was found between the GSI of maturing and mature males and the number of anal-fin rays bearing hooks from August to January. All specimens bearing gill glands were mature or undergoing maturation, and the frequency of occurrence of the gill glands increased with a rise of GSI.

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BARKHALOV, Ruslan Magomedovich, Nukhkadi Ibragimovich RABAZANOV, Kais Magomedovich GUSEINOV, Ziyatdin Magomedzagirovich KURBANOV, Aysha Sharapatinovna GASANOVA, Evgeny Nikolaevich LOBACHEV, and Zuri Salmanovna KURBANOVA. "BIOLOGY OF NORTH CASPIAN ROACH RUTILUS RUTILUS CASPICUS (JAKOWLEW, 1870) OF THE NORTHERN DAGHESTAN CASPIAN COAST." Herald of Daghestan Scientific Center of Russian Academy of Science, no. 72 (March 30, 2019): 12–16. http://dx.doi.org/10.31029/vestdnc72/2.

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The article is devoted to the study of biological characteristics of the north Caspian roach of the Daghestan coast of the Caspian Sea. Discussed are size and weight, fatness, passing the stage of gonad maturity, the absolute individual fecundity and feeding habits. The degree of occurrence of organisms in the food lumps with identification of dominant groups is determined.

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Ovsyannikov, V. P., A. Yu Nemchenko, and A. N. Kanzeparova. "ASIATIC SMELT OSMERUS DENTEX STEINDACHNER ET KNER, 1870 OF THE UDA RIVER (NORTHWESTERN OKHOTSK SEA) — BIOLOGY, ECOLOGY, FISHERY." Izvestiya TINRO 199 (December 3, 2019): 83–97. http://dx.doi.org/10.26428/1606-9919-2019-199-83-97.

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Data on biology, ecology and fishery of asiatic smelt in the Uda River during its spawning migration are analyzed. The spawning begins in May-June in 2–11 km from the river mouth and lasts 3–10 days. Timing of its start varies from May 22 (2014 and 2018) to June 14 (2001), with 24 days difference. The spawning migration begins under the water temperature 6.0 оС, during the spawning the temperature varies from 6.2 to 11.9 оС. The river flow velocity on the spawning grounds is 1.2–2.6 m/s, the river depth varies from 0.3 to 2.5 m. Age of the spawners is 2–8 years, their length is 11.5–32.0 cm and weight 10.8–275.0 g, males usually prevail in number (63–81 %). Depending on the year-class strength, the fish in age of 3 or 4 years prevail among the spawners. After spawning, females leave the spawning grounds immediately — in that time their occurrence in the catches below the spawning grounds can reach 85 %. Size of the spawners decreases during the migration, for males the decreasing was from 19.0 to 15.0 cm in 2007, from 20.2 to 18.8 cm in 2014, from 19.3 to 16.6 cm in 2015, and from 19.4 to 16.0 cm in 2016, for females — from 21.0 to 18.0 cm in 2007, from 22.1 to 19.6 cm in 2014, from 21.3 to 19.0 cm in 2015, and from 24.5 to 16.1 cm in 2016. Annual increments of the smelt body length are 0.7–7.8 cm, on average 3.9 cm, for the body weight 17.1–39.9 g, on average 32.1 g. The minimum registered size of mature male and female was 11.5 and 13.0 cm, respectively. Percentage of the smelt with non-commercial size during spawning migration was 19.2 % in 2007, 0.4 % in 2014, 15.4 % in 2015, and 28.4 % in 2016. The group linear growth of asiatic smelt could be approximated by Bertalanffy equation: L = 30.5 [1 – e–0.317 (t – 0.533)]. Its body length dependence on weight is described by the equation of simple allometry: W = 0.002 L3.380 (determination r 2 = 0.92–0.99). The body weight depends on age as the function: Wt = 2.974t 2.136. Individual absolute fecundity of the smelt in the Uda varies from 11300 to 141300 eggs, on average 52500 eggs in 2016 and 50400 eggs in 2007; these values are close to the smelt fecundity in the Ulbeya and Inya rivers. The fecundity variation generally increases with the age: the registered ranges of absolute fecundity (thousand eggs) were, by age groups: 19.1 for 3 years, 53.5 for 4 years, 37.8 for 5 years, 57.5 for 6 years, and 60.3 for 7 years old fish, the ranges of relative fecundity (eggs/g of body weight) were: 864, 537, 565, 501, and 449 eggs/g for the same age groups. The total population fecundity was 32.7. 109 eggs in 2016. The individual absolute fecundity has the following dependencies on body length, weight, and age: AF(L) = 0.001 L3.437, AF(W) = 0.650 W0.986, and AF(t) = 1.661 t 2.250, respectively. The stock of asiatic smelt in the Uda is represented by migrating fish only. Its fishery was conducted by 8 companies, their total annual landing increased from 10 t in 2012 to 373 t in 2017 and slightly decreased recently: the mean landing for 2013–2019 was 276 t. The spawning biomass of smelt was estimated from 637 to 1734 t, by years, that was about 70 % of the biomass of mature smelt in the Shantar Sea.

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Voinova, Tatyana Victorovna. "ON FERTILITY OF BLACK-BACKED SHAD ALOSA KESSLERI KESSLERI (GRIMM, 1887)." Vestnik of Astrakhan State Technical University. Series: Fishing industry 2021, no. 3 (September 30, 2021): 77–85. http://dx.doi.org/10.24143/2073-5529-2021-3-77-85.

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The article highlights the results of studying the individual absolute fertility (IAF) of black-backed shad Alosa kessleri kessleri (Grimm, 1887). The data were obtained during the species’ spawning run in the Volga River. A positive correlation was established between IAF and the linear indicators, weight and age of producers. IAF ranged from 38.0 to 333.9 thousand eggs. The average absolute fecundity of herring varied from 38.8 to 259.2 thousand eggs. In the 1970s black-backed shad of 26-42 cm long had fluctuations in the average absolute fecundity from 88.4 to 258.5 thousand eggs. At the present stage, the size range of spawning shoals suggests that maturity in black-backed shad occurs at a body length of 22-45 cm, the reproductive capacity is regulated by early maturation. The results of studies on the fertility of black-backed herring of various lengths in 1 g of ovary have been obtained. There has been registered a wide range of fluctuations in the number of eggs (from 4033 to 14147 pcs). Differences in the size of ovaries indicate a qualitative definiteness of the physiological readiness of females in the pre-spawning period. The fluctuations in the average individual absolute fertility were revealed depending on body weight and age. Fertility in one-size groups and the reproductive capacity of the population as a whole change due to habitat conditions. The conditional indicator of the population fertility was calculated. The results of the obtained fertility data compared with the data of previous years indicate a 1.5-fold decrease in reproductive capacity of the population at the present time, which indicates a stressed state of the reproductive capacity of female species

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Gonçalves, Patrícia, Ana Maria Costa, and Alberto G. Murta. "Estimates of batch fecundity and spawning fraction for the southern stock of horse mackerel (Trachurus trachurus) in ICES Division IXa." ICES Journal of Marine Science 66, no. 4 (May 1, 2009): 617–22. http://dx.doi.org/10.1093/icesjms/fsp066.

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Abstract Gonçalves, P., Costa, A. M., and Murta, A. G. 2009. Estimates of batch fecundity, and spawning fraction for the southern stock of horse mackerel (Trachurus trachurus) in ICES Division IXa. – ICES Journal of Marine Science, 66: 617–622. Since 1995 the annual egg production method has been applied triennially to the southern stock of horse mackerel (Trachurus trachurus) in the Northeast Atlantic (ICES Division IXa). This method assumes that fecundity is determinate, but increasing evidence indicates that horse mackerel are indeterminate spawners. The daily egg production method (DEPM) does not rely on the assumption of determinate fecundity, making it the appropriate method for this species. Therefore, we reanalysed samples collected from previous surveys (2002, 2004, 2005, and 2007) to obtain estimates for batch fecundity and spawning fraction, which are important DEPM parameters. The estimates of batch fecundity are around 200 oocytes g−1 of female (total ovary-free weight). Several criteria were used to estimate spawning fraction (migratory nucleus stage, hydrated oocytes, and post-ovulatory follicles) and all showed the same trend among years, varying between 0.10 and 0.30 d−1. The estimates were significantly different among methods, but those differences were similar across surveys, indicating that a consistent bias would be reflected in the final spawning-stock biomass (SSB) estimates obtained from the DEPM. Until further information is available regarding the accuracy of the criteria used to estimate spawning fraction, the southern horse mackerel SSB estimates from the DEPM should only be taken as indicative of trends rather than measures of absolute abundance.

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Onwuka, C. N., A. Francis, and F. D. Sikoki. "Aspects of the biology of the African lungfish, Protopterus annectens (owen, 1839) in orashi and Sombreiro Rivers, Rivers State, Nigeria." Journal of Aquatic Sciences 31, no. 2C (June 28, 2017): 529–42. http://dx.doi.org/10.4314/jas.v31i2c.20.

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Aspects of the biology of the African lungfish, Protopterus annectens (Owen, 1839) from Orashi and Sombreiro Rivers in Rivers State, Nigeria were investigated using routine biological approaches. Samples were collected between October 2012 and September 2013. The analysis of the stomach content showed that the fish from both rivers fed mainly on detritus, which accounted for 100% of the stomachs examined. Other food items included remains of higher plants, filamentous algae and diatoms. A sex ratio of 1:1 male: female was observed, although, females were more predominant than males during the greater part of the year, corresponding to rainy season. The proportion of males in the catch gradually increased as females reduced in number with the approach of the dry season. The GSI showed peak in the months of January, February and March. There was a decline from April to June as the fish had finished spawning. The monthly changes in GSI suggest that the fish had distinct period of maturity and breeding. The fish were found to be highly fecund. The individual/absolute fecundity ranged from 32,009 to 147,003 with a mean value of 6,653. Relative fecundity ranged from 362 to 529g-1 body weight. The fecundity profile of P. annectens shows that the fish has a remarkable reproductive potential in the two Rivers.Keywords: Detritus, gonado-somatic index, fecundity, Protopterus annectens

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La Mesa, Mario, Vincenzo Caputo, and Joseph T. Eastman. "Gametogenesis in the dragonfishes Akarotaxis nudiceps and Bathydraco marri (Pisces, Notothenioidei: Bathydraconidae) from the Ross Sea." Antarctic Science 19, no. 1 (February 28, 2007): 64–70. http://dx.doi.org/10.1017/s0954102007000090.

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We analysed histological characteristics of gonads and reproductive effort of the small deep-living dragonfishes Akarotaxis nudiceps (Waite) and Bathydraco marri Norman collected in the south-western Ross Sea. From a macroscopic point of view, most specimens of B. marri were juveniles in early stages of gonad maturity, except for a maturing female. Conversely, the sample of A. nudiceps was composed of both immature and adult fish in different stages of maturity. A single A. nudiceps female was mature with a gonadosomatic index of 9.8%. Its absolute and relative fecundity was 260 oocytes and 31.5 oocytes g−1 TW, respectively, with a mean size of ripe oocytes of 1.9 mm. Gametogenesis in both species closely resembled that observed in other notothenioids, with females possessing two well-defined groups of oocytes. One group consisted of previtellogenic oocytes as a reserve stock while the other group was maturing oocytes to be ovulated in the current spawning season. A distinctive feature of oogenesis in recovering and maturing females of A. nudiceps was the presence of both postovulatory follicles in different stages of reabsorption and atretic oocytes. Based on low absolute fecundity, it is possible that A. nudiceps provides parental care and egg guarding.

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Praveen, Agnihotri, Sarkar Uttam Kumar, Nagpure Naresh Sahebrao, Mishra Rahsya Mani, Kumar Ravindra, Awasthi Abhishek, and Pandey Brijesh Kumar. "Dynamics of reproductive ecology of the fish Ompok bimaculatus (Siluriformes: Siluridae) in six tropical rivers of the Ganges basin, India." UNED Research Journal 9, no. 1 (March 14, 2017): 73–85. http://dx.doi.org/10.22458/urj.v9i1.1681.

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The silurid butter catfish, Ompok bimaculatus (Bloch, 1794), is widely distributed in the plains and sub-mountain regions of India, but not enough is known about its reproductive potential is still insufficient. The present study evaluated the comparative reproductive potential (in terms of sex ratio, spawning season, body size at first gonadal maturity, gonadosomatic index, fecundity, egg dimension, egg weight etc.) of fish (n=1223) from six tropical tributaries of the Ganges basin during January 2011-December 2013. The females had relatively greater weight and length. The body size at 50% first gonadal maturity (L50%) ranged between 228-262mm in females and 198-247mm in males. The population has high and low fecundities. The correlations between absolute fecundity and total length, as well as between body weight and gonad weight, were significant (p<0.05) and positive in all the population.

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Keymer, A. E., and R. W. Hiorns. "Faecal egg counts and nematode fecundity: Heligmosomoides polygyrus and laboratory mice." Parasitology 93, no. 1 (August 1986): 189–203. http://dx.doi.org/10.1017/s0031182000049933.

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SUMMARYThe results are presented of an experimental investigation of the relationship between faecal egg counts and worm burden in outbred MF1 mice infected with Heligmosomoides polygyrus (Nematoda). The sex-ratio of the adult parasites was found to be significantly female biased, but independent of parasite burden. Evidence was also found to suggest a significant association between parasite density and mating success. The linear logarithmic relationship (gradient of approximately 2) between the variance and mean of repeated egg counts from individual mice could not be disrupted by controlled experimental conditions, and is therefore concluded to be an inherent feature of the biology of helminth-host interactions. A significant positive association was detected between host faecal output and parasite fecundity; further investigation of the cause of this association is now required. Average faecal production was found to be inversely related to worm burden. In combination, the above two factors account partly, but not completely, for the observed density dependence in the absolute rate of parasite egg production. Two epidemiological consequences of the relationship between faecal production and parasite fecundity are discussed. First, absolute rates of egg production can only be estimated by temporal egg counts (epd). Secondly, measurements of egg production/g of faecal material (epg) are more reliable indicators of worm burden than measurements of epd. Both faecal output and worm fecundity respond as might be predicted to a period of host food deprivation; faecal egestion and measurements of epd are signifcantly depressed, and measurements of epg are significantly increased. The data are consistent with the hypothesis that egg production and faecal output are causally associated, but that other factors relating to parasite density also influence egg production. Of the possible causes for the high variability in parasite egg production between mice harbouring low number of worms, the most likely explanation seems to be host heterogeneity (possible genetic in origin). This is discussed in relation to similar patterns observed in data collected from human populations in areas of endemic helminth infection.

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Reid, Jenny E., and Gérald Chaput. "Spawning history influence on fecundity, egg size, and egg survival of Atlantic salmon (Salmo salar) from the Miramichi River, New Brunswick, Canada." ICES Journal of Marine Science 69, no. 9 (June 19, 2012): 1678–85. http://dx.doi.org/10.1093/icesjms/fss091.

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Abstract Reid, J. E., and Chaput, G. 2012. Spawning history influence on fecundity, egg size, and egg survival of Atlantic salmon (Salmo salar) from the Miramichi River, New Brunswick, Canada. – ICES Journal of Marine Science, 69: 1678–1685. There is an increasing abundance of repeat spawners in the Atlantic salmon (Salmo salar) population in the Miramichi River that, owing to their larger size, can be expected to contribute greater egg depositions and better offspring survival than primarily maiden spawning populations. Currently, there is little information on the reproductive contribution of repeat-spawning salmon. In this study, the fecundity, egg size, and egg survival for 235 maiden and repeat-spawning wild female Atlantic salmon were examined over a period of 3 years. Relative fecundity did not differ among the largest body size group of salmon, but consecutive repeat spawners had a higher fecundity than maiden 2SW salmon and alternate repeat spawners. Egg diameter also increased with body size, but consecutive repeat spawners had significantly smaller eggs, in absolute terms and relative to their body size, than maiden 2SW salmon and alternate repeat spawners. The egg survival rate of consecutive repeat spawners was significantly lower than that of 2SW maiden salmon and alternate repeat spawners. Consecutive repeat spawners are different in that egg diameter and egg survival did not follow the general positive association with female body size, probably because of the short time that they spend reconditioning in the ocean and consequently their available energy reserves.

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El-Mor, Mohammad, Souad A. M. Moftah, Yousef K. A. Abdalafid*, and Bulkasim M. Abdulnabi. "Some aspects of the reproductive physiology of the Flathead grey mullet Mugil cephalus (Linnaeus, 1758) in Benghazi coast, eastern Libya." International Journal of Bioassays 5, no. 04 (April 22, 2016): 4996. http://dx.doi.org/10.21746/ijbio.2016.04.008.

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The reproductive physiology of 530 specimens of Mugil cephalus (Family: Mugilidae) were collected from catches by gill and trammel nets operating on Benghazi coast on Mediterranean Sea - Libya was studied, there were monthly variations in sex ratio and a tendency for females (298 fish = 56.2%) than males (232 fish = 43.8%) for the whole population, Overall sex ratio was (1 : 1.28) for males to females respectively, First maturation size was determined for females L50 = 34.1 cm and for males L50 = 32.3 cm, All individuals have definite breeding season which extends from July to October, An increase in Oocyte diameters was evident in July (489 µ ± 5.34), and this increase continued in the following months till October (599 µ ± 11.04), the absolute fecundity ranged from 578981 to 2598022 for fish total length ranging from 19.5 to 47.4 cm, whereas relative fecundity ranged from 29036 to 57352 / cm.

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Kessia Irène, Kouakou Fokouo, Koné Tiéhoua, Soro Yaya, N’Da Konan, and Ouattara Mamadou. "Reproduction De Heterotis Niloticus (Cuvier, 1829) De La Riviere Agneby (Cote d’Ivoire)." European Scientific Journal, ESJ 12, no. 6 (February 29, 2016): 83. http://dx.doi.org/10.19044/esj.2016.v12n6p83.

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The reproductive biology of Heterotis niloticus has been studied from monthly samples taken from artisanal fishing on the Agneby river during the period june 2013 to May 2015. The whole sample consisted of 498 specimens of which 269 females and 229 males were examined. Sex-ratio observed was in favour of females (1: 1.17; X2 = 3.21; p > 0.05). The monthly evolution of the gonado-somatic index (GSI), the liver-somatic index (LSI), the condition factor (K) and maturation stages suggests that this fish has two periods of reproduction. The two periods were respectively from june to august and from november to december. The standard length at first sexual maturity was 490.6 mm for females and 436.3 mm for males. The absolute fecundity was ranged from 5424 to 25591 oocytes in females of 595 mm to 780 mm standard length. The relative fecundity was 3752± 1491 oocytes/kg of female.

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Lampert, Vinicius Renner, Marco Aurélio Azevedo, and Clarice Bernhardt Fialho. "Reproductive biology of Bryconamericus stramineus Eigenmann, 1908 (Ostariophysi: Characidae) from the Rio Ibicuí, RS, Brazil." Brazilian Archives of Biology and Technology 50, no. 6 (November 2007): 995–1004. http://dx.doi.org/10.1590/s1516-89132007000700011.

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Reproduction of Bryconamericus stramineus was described based on the analysis of 208 females and 166 males collected monthly in the Rio Ibicuí, from April 2001 through March 2002. Reproduction occurred between September and December, with a lower peak in February. The mean absolute fecundity was 371.3 (± 244.6) oocytes and the mean relative fecundity was 0.35 (± 0.08) oocytes/mg of total weight and the fish was a multiple spawner. A weak correlation between GSI of males and day length was observed. Other parameters (stomach repletion and hepatosomatic index, rainfall and temperature) did not show any correlation with GSI. However, some of these factors might act as "starters" of gonadal maturation. The presence and frequency of fin ray hooks on the males was compared with the gonadal maturation stages, months and standard length classes. Well-developed hooks were found mainly in the mature males during the reproductive period and in the largest individuals.

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J. Imanpour Namin, F. Tari, Abdolmalaki Shahram, and M. Hadavi. "Reproductive biology of Caspian vimba, Vimba vimba (L.), in the coastal waters of the southwestern Caspian Sea." Archives of Polish Fisheries 23, no. 3 (September 1, 2015): 171–80. http://dx.doi.org/10.1515/aopf-2015-0020.

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Abstract The reproduction biology of Caspian vimba, Vimba vimba (L.), was investigated on the southwestern coast of the Caspian Sea using 712 fish specimens collected at three fisheries catch stations located in Talesh, Anzali, and Kiashahr over a two-year period from April 2012 through June 2013. Seasonal changes in the gonadosomatic index, gonad histological status, size frequency distribution of oocytes, and the fecundity of the species were studied. The peaks of the gonadosomatic index (GSI) were observed both in females and males in June 2012 and May 2013 indicating the variable peak spawning time of this species. Histological examinations and oocyte frequency distribution patterns showed synchronous oocyte development in the Caspian vimba. Absolute fecundity ranged from 5873 to 35421 eggs. The size at first maturity for females was 120 mm FL. We concluded that the Caspian vimba is a total spawner with variable spawning dependent on environmental factors.

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Bailly, Dayani, Valéria Flávia Batista-Silva, Milza Celi Fedatto Abelha, Elaine Antoniassi Luiz Kashiwaqui, Carlos Alexandre Fernandes, and Edson Dias de Carvalho. "Relative abundance and reproductive tactics of a Loricariidae species at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil." Biota Neotropica 11, no. 3 (September 2011): 171–78. http://dx.doi.org/10.1590/s1676-06032011000300014.

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This study aimed to evaluate population abundance patterns and the main events in the reproductive cycle of Loricariichthys platymetopon at Saraiva Lagoon, Ilha Grande National Park, MS-PR, Brazil. Monthly samplings were conducted from October 2004 to September 2005 in three sections of the lagoon: entrance, middle and end, which resulted in the capture of 175 individuals. Spatial and temporal variation in abundance was obtained through CPUE (number of captured individuals/1000 m² of gillnets in 12 hours). The reproductive tactics considered were: duration, time and location of spawning, oocyte diameter and fecundity. The highest relative abundance was recorded in February, in the middle section of the lagoon, and the reproductive period lasted from September to February. The prevalence of females with spent ovaries and at rest in the following months indicated that reproductive activity ceased during autumn and winter. We observed that reproduction was high at the end section of the lagoon. The recorded mean oocyte diameter was 1.67 (SD ± 0.76) mm, mean absolute fecundity was 962.1 (SD ± 382.48) oocytes, and relative fecundity was 7.60 (SD ± 2.25) oocytes/g and 5.13 (SD ± 0.75) oocytes/cm. These tactics, probably are related to the settlement of L. platymetopom in Saraiva Lagoon, as well as in the different biotopes of the Upper Paraná River floodplain.

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Calvo, Jorge, Elba Morriconi, and Gustavo A. Rae. "Reproductive biology of the icefish Champsocephalus esox (Günther, 1861) (Channichthyidae)." Antarctic Science 11, no. 2 (June 1999): 140–49. http://dx.doi.org/10.1017/s0954102099000206.

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Champsocephalus esox is the only icefish species found outside Antarctica. In a population from the Beagle Channel, the complete annual reproductive cycle has been determined. Gonad maturity stages have been established for males and females by histological analysis. Males are sexually mature from January–September with a maximum gonadosomatic index (GSI) of 3.63%. Histologically, testes are very homogeneous and the degree of maturation of the testicular cysts is similar among different tubules at the same maturation stage. Running ripe testes have mature sperm and a few spermatogoniae arranged near the blind end of the tubules. In sexually active females that are found from February–November, ovaries contain only ripe oocytes or postovulatory follicles, together with a batch of previtellogenic oocytes. During hydration, oocyte diameter reaches 2.7 mm, and oocyte dry weight increases due to material intake, the maximum GSI in ovulated ovaries is 21.89 and hepatosomatic index (HSI) decreases. These facts suggest a transfer of matter from liver to the gonads. Absolute fecundity ranges from 3303–8600 oocytes. Relative fecundity ranges from 22.5–43.5 oocytes per gram total weight. In C. esox, relative fecundity has a similar range to those quoted for the different C. gunnari populations, whilst mature oocyte diameter is small and reproductive season extended compared to the same parameters in other Channichthyidae.

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Esteban, Nicole, Jeanne A. Mortimer, and Graeme C. Hays. "How numbers of nesting sea turtles can be overestimated by nearly a factor of two." Proceedings of the Royal Society B: Biological Sciences 284, no. 1849 (February 22, 2017): 20162581. http://dx.doi.org/10.1098/rspb.2016.2581.

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Estimating the absolute number of individuals in populations and their fecundity is central to understanding the ecosystem role of species and their population dynamics as well as allowing informed conservation management for endangered species. Estimates of abundance and fecundity are often difficult to obtain for rare or cryptic species. Yet, in addition, here we show for a charismatic group, sea turtles, that are neither cryptic nor rare and whose nesting is easy to observe, that the traditional approach of direct observations of nesting has likely led to a gross overestimation of the number of individuals in populations and underestimation of their fecundity. We use high-resolution GPS satellite tags to track female green turtles throughout their nesting season in the Chagos Archipelago (Indian Ocean) and assess when and where they nested. For individual turtles, nest locations were often spread over several tens of kilometres of coastline. Assessed by satellite observations, a mean of 6.0 clutches (range 2–9, s.d. = 2.2) was laid by individuals, about twice as many as previously assumed, a finding also reported in other species and ocean basins. Taken together, these findings suggest that the actual number of nesting turtles may be almost 50% less than previously assumed.

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Chaubey, Brijesh Kumar, Farah Bano, and Mohammad Serajuddin. "Comparative Study of Reproductive Traits in Gangetic Hairfin Anchovy, Setipinna phasa (Hamilton, 1822) from Estuarine and Freshwater Ecosystems." Turkish Journal of Fisheries and Aquatic Sciences 21, no. 04 (January 14, 2021): 179–89. http://dx.doi.org/10.4194/1303-2712-v21_04_03.

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The Gangetic hairfin anchovy, Setipinna phasa (Hamilton, 1822) were collected from river Ganga (Kanpur) and Hooghly estuary (Kolkata) to study the comparative reproductive traits (sex ratio, spawning season, gonado-somatic index, fecundity and egg diameter). Female outnumbered the male in the population of river Ganga but it was non-significant in the population of the estuary. Five maturity stages were identified in males and females of the fish of both ecosystems. Occurrence of multimodal (immature, maturing and mature) and uni-modal (matured) type of ova in the ovary of the fish of Hooghly estuary and river Ganga respectively and the values of gonado-somatic index confirmed the double and single spawning in a year in the fish in estuary and river respectively. The absolute fecundity was found to be higher in the fish of river Ganga compared to that of the estuary (P < 0.05). Linear and positive correlations between fecundity and the total length, body weight, ovary length and ovary weight were noted in the fish of both ecosystems (R2 > 0.90). The present study provides the comparative account of the reproductive and spawning strategies of S. phasa for the first time in favour of the proper management and conservation of the fish.

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Pandey, NN, Amrita Rani, Bipin Vishwakarma, Raghvendra Singh, and D. Sarma. "STUDY OF GONADO-SOMATIC INDEX AND ABSOLUTE FECUNDITY OF BANGANA DERO (HAMILTON, 1822) UNDER COLDWATER CONDITIONS." International Journal of Advanced Research 6, no. 6 (June 30, 2018): 235–38. http://dx.doi.org/10.21474/ijar01/7206.

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Silvano, Jacira, Cristina L. C. Oliveira, Clarice B. Fialho, and Hélio C. B. Gurgel. "Reproductive period and fecundity of Serrapinnus piaba (Characidae: Cheirodontinae) from the rio Ceará Mirim, Rio Grande do Norte, Brazil." Neotropical Ichthyology 1, no. 1 (September 2003): 61–66. http://dx.doi.org/10.1590/s1679-62252003000100007.

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Specimens of Serrapinnus piaba were collected monthly from April 2001 to April 2002 in the rio Ceará Mirim, Rio Grande do Norte State, Brazil. The reproductive period, determined through the monthly variation of the gonadosomatic index (GSI) and maturation stages, occurred from January to April. Non-parametric Spearman test was performed in order to test correlation of monthly GSI variation in males and females with water temperature, rainfall and day length. Rainfall and Temperature were correlated with GSI variation in females only and day length showed a negative correlation with GSI variation of males only. It was verified the presence of hooks on the anal fin of mature and maturing males along all the period of study. The absolute fecundity mean was 441 (±178.08) oocytes, determined by the number of yolky oocytes counted in 27 mature female gonads. The relative fecundity, estimated by the number of yolky oocytes divided by milligram of total body weight was 0.74 (± 0.19).

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Kirczuk, Lucyna, Katarzyna Dziewulska, Przemysław Czerniejewski, Adam Brysiewicz, and Izabella Rząd. "Reproductive Potential of Stone Moroko (Pseudorasbora parva, Temminck et Schlegel, 1846) (Teleostei: Cypriniformes: Gobionidae) Inhabiting Central Europe." Animals 11, no. 9 (September 7, 2021): 2627. http://dx.doi.org/10.3390/ani11092627.

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Similar to other invasive species, stone moroko is extending its global distribution. The present study aimed to assess the reproductive potential of stone moroko fish in a new habitat in Poland based on analysing the sexual cycle and fecundity. Fish morphometric data, age, and gonadal structures were analysed. Fish age ranged from 0+ to 5+ years. Most females and males (93% and 60%, respectively) had reached sexual maturity in the first year of their life, with the smallest length of 25 mm and 28 mm, respectively. The mean, standard length of the body was 50 mm. The spawning season was spread over four months from late-April to mid-August. Females laid eggs in portions, and the absolute and relative fecundity was 1372 and 1691, respectively. Stone moroko males were ready to spawn for a longer time period than females. The present study shows greater reproductive potential of stone moroko population in the central Europe than the native population, suggesting its successful colonisation in the new habitat.

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Verba, Júlia T., Vinicius R. Lampert, and Marco A. Azevedo. "Reproductive traits of Gymnogeophagus labiatus (Teleostei, Cichlidae), in an upper stretch of Sinos river, Caraá, Brazil." Iheringia. Série Zoologia 101, no. 3 (September 2011): 200–206. http://dx.doi.org/10.1590/s0073-47212011000200007.

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This work describes the reproduction of Gymnogeophagus labiatus (Hensel, 1870) from an upper stretch of Sinos river, southern Brazil, based on the analysis of 174 males and 132 females captured in monthly samples taken from January to December 2007. Results showed that reproductive activity occur in spring and summer although ripe males were found along the year. The standard length of the smallest ripe male was 104.74 mm (Lt) and the smallest ripe female was 55.00 mm (Lt). There was a significant difference in total sex ratio, with 1.32 males to each female (χ2 = 5.76). Males were much more abundant in March (1.75 males: 1 female) and December (5 males: 1 female). Females were more abundant in the 62├77 mm interval (1 male: 2.36 female) while males were more abundant in the 77├92 mm size interval (2.57 males: 1 female). The largest length intervals were composed of only males. Mean absolute fecundity was 113.4 (± 31.24 sd) and mean relative fecundity was 0.0125 (± 0.0026 sd) oocytes/mg. In ripe ovaries, small-diameter oocytes were observed at high frequencies while larger ones occurred at lower frequencies. This pattern is common in fishes with asynchronous oocyte development. Characteristics of G. labiatus, such as low fecundity, asynchrony in oocyte development, multiple spawning, and its well-known parental care behavior, are consistent with an equilibrium strategy, as proposed for other cichlids.

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Tiogué, Claudine Tekounegning, Boddis Tsiguia Zebaze, Paul Zango, and Minette Eyango Tomedi-Tabi. "Reproductive Strategy of Chrysichthys nigrodigitatus (Lacepede, 1803) in a Natural Environment in the Nkam River, Littoral Cameroon." International Journal of Zoology 2020 (February 15, 2020): 1–8. http://dx.doi.org/10.1155/2020/1378086.

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A study on the reproductive strategy of Chrysichthys nigrodigitatus was conducted from October 2015 to August 2016, in the Nkam River in Yabassi, Littoral Region of Cameroon. For this purpose, 154 specimens of C. nigrodigitatus with total mean weight of 829.96 ± 829.58 g and total mean length of 367 ± 156 mm collected from artisanal fishermen were used. Twenty-nine (29) females at stage V of sexual maturity were selected for the evaluation of the fecundity. It appears that the oogenesis in C. nigrodigitatus is of an asynchronous type with multiple laying spread over a long period. The gonadosomatic index (GSI) peaks in June (17.9 ± 7.1 for females and 1.06 ± 0.27 for males). Hepatosomatic index (HSI) was higher in females than in males throughout the year. The mean condition factor K was 1.07 ± 0.09%. The breeding season occurred from April to October during the rainy season. Gonadosomatic and hepatosomatic indices were positively correlated with rainfall, contrary to the K factor, which has been strongly and negatively correlated with this physical parameter. The sex ratio of 1M: 1.5F was in favour of females, thus reflecting an “r” type reproductive strategy. Absolute fecundity was estimated at 1374 ± 1022 oocytes for individuals of 107.3 ± 111.9 g mean weight. Mean relative fecundity was 14 ± 3 oocytes/g of body weight. It was recommended that future work focuses on the captivity of this species.

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Otoyo, J., S. M. Ameh, and O. K. Achema. "Studies on fecundity and spawning of blue crab (Callinectes Amnicola) in Cross River Estuary." Journal of Aquatic Sciences 36, no. 1 (August 3, 2021): 75–82. http://dx.doi.org/10.4314/jas.v36i1.7.

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Studies on identification of species, fecundity and development stages of blue crab, (Callinectes amnicola) were investigated at the Cross River Estuary between the months of December, 2018 and May, 2019. The parameters used for the study were gonadosomatic and hepatosomatic indices, egg diameter and counts. All measurements followed standard procedures. Gonadosomatic index was at its peak in December (88.9) and April (83.3). This coincided with the peak in egg size suggesting that spawning occurred twice within the period.The low values of hepatosomatic index around December (1.20) and April (0.45) added to confirm the spawning in these months. The species spawns at a mean egg size of 17.55mm. The dimension of crabs examined were in the following range: carapace length 40.0 to 70.0mm, carapace width, 5.0 to 60mm and body weight 40.0 to 140.0g. The relationship between fecundity and weight of crab was significant (r = 0.295: p<0.05), indicating positive correlation. Absolute fecundity of the species ranged between 1,375 and 225,132 eggs. The smallest crab with egg had a carapace width of 39.5mm and weight of 46.9g. Spawning at this size seems to be a strategy adopted by the species to cope with exploitation pressure. The result of this study revealed that C. amnicola had a high reproductive potentials. Hence, adequate regulation is required to enhance sustainability of the species in the Cross River Estuary.

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Nemati, Alireza, Elham Riahi, and Saadollah Houshmand. "Sensitivity and elasticity analysis of Tetranychus urticae Koch population parameters: Consequences for pest management." Systematic and Applied Acarology 25, no. 2 (February 21, 2020): 268–84. http://dx.doi.org/10.11158/saa.25.2.8.

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Sensitivity and elasticity analyses quantify the effect of an absolute and proportional change in demographic variables on population growth rate (λ), respectively. The methods are used to identify the variable(s) that have the largest influence on λ. Tetranychus urticae Koch is one of the most polyphagous tetranychid mites which has been collected from plenty plant species including agricultural and horticultural crops. In this study, sensitivity and elasticity analyses were used to investigate the effects of various demographic variables on λ at five different temperatures (15, 20, 25, 30 and 35 °C), using both age- and stage-structured matrix models. Considering the sensitivity of λ to age-dependent fecundity rates (fx), it was found that starting oviposition one day earlier was associated with the highest sensitivity compared to the other age classes, irrespective of temperature. Besides, results from both age- and stage-structured matrix models indicated that λ is more sensitive to changes in survival rates than in fecundity rates at all temperatures. Furthermore, female individuals at the ages of 46, 23, 14, 11 and 7 days had the highest contribution to population growth in comparison with other ages, when reared at the above-mentioned temperatures, respectively. Also, the sensitivity of λ to the changes in survival of adults was higher than in other stages. Besides, the elasticity to fecundity rate at the age of first reproduction was considerably higher than those associated with the age of last reproduction. The survival rates (si) generally exhibited a higher elasticity than the transition rates (gi). Overall, adult survival had the highest influence on λ followed by immature survival, egg survival, and female fecundity. Consequently, management efforts that aim at decreasing adult survival are likely to yield the best results with regard to reducing the growth rate of T. urticae.

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Lampert, Vinicius Renner, Marco Aurélio Azevedo, and Clarice Bernhardt Fialho. "Reproductive biology of Bryconamericus iheringii (Ostariophysi: Characidae) from rio Vacacaí, RS, Brazil." Neotropical Ichthyology 2, no. 4 (December 2004): 209–15. http://dx.doi.org/10.1590/s1679-62252004000400003.

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In this paper we describe some aspects of the reproduction and development of secondary sexual characters of Bryconamericus iheringii, based on the analysis of 194 females and 210 males collected monthly in the rio Vacacaí (30º21'34"S and 54º18'48"W), from April 2001 to March 2002. The reproductive period occurred from September to January (spring and summer in the Southern Hemisphere), as described for other characids of the same area. The absolute fecundity mean was 933.71 ± 303.10 oocytes, and the relative fecundity mean was 0.36 ± 0.08 oocytes per mg of total weight, being the species a multiple spawner. There was no correlation between the values of GSI and variation of biotic (stomach repletion and hepatosomatic indexes) and abiotic data (rainfall, day length and temperature) but we suggest that these factors can influence the reproduction of the species acting as "starters" of the beginning of gonadal maturation. Fin-ray hooks consist in a sexually dimorphic character of the species. Well developed hooks were found mainly in mature males, during the reproductive period and in the largest individuals.

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Martins-Queiroz, Mirian F., Lúcia A. de F. Mateus, Valdener Garutti, and Paulo C. Venere. "Reproductive biology of Triportheus trifurcatus (Castelnau, 1855) (Characiformes: Characidae) in the middle rio Araguaia, MT, Brazil." Neotropical Ichthyology 6, no. 2 (2008): 231–36. http://dx.doi.org/10.1590/s1679-62252008000200010.

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The study of the reproductive biology of Triportheus trifurcatus of the middle rio Araguaia was carried out using 275 specimens obtained in seven collections conducted in the period between November 2003 and January 2005. Females prevailed among the classes of intermediate length, as well as in the total number of samples. On the other hand, males prevailed in the smaller classes. The average length of females was larger than that of males. Four stages of gonadal maturation were macro- and microscopically identified: B - maturation, C - mature, D - spent and E - resting. Stage A (immature) was not found in the habitats sampled. The smallest-length male was 110 mm in standard length, and the smallest female, 119 mm. The spawning period occurred from November to January, with reproductive peak in December/January, coinciding with the highest water levels. The absolute fecundity is considered low, and there is a positive correlation between fecundity and gonad weight, body weight and standard length. Food ingestion during the reproductive period did not suffer any interference, and it is suggested complete spawning for this species.

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Kock, K. H., L. K. Pshenichnov, and A. L. Devries. "Evidence for egg brooding and parental care in icefish and other notothenioids in the Southern Ocean." Antarctic Science 18, no. 2 (June 2006): 223–27. http://dx.doi.org/10.1017/s0954102006000265.

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One of the least known Antarctic fish species is the icefish Chionobathyscus dewitti described first in 1978. Some of its reproductive characteristics appear to be similar to other channichthyids of similar size and shape. Females close to spawning have gonado–somatic indices (GSIs) of more than 20, and absolute fecundity was 2967 to 15612 oocytes in females 33–62 cm long. Relative fecundity was 7.6 in one female. Spawning has been observed in the Ross Sea at 1300 to 1500 m depth from January to March. Chionobathyscus dewitti may exhibit a remarkable egg carrying behaviour: eggs stick together in batches around the pelvic fins of females. The comparatively large number of mature males observed with no indication of an egg batch attached to their ventral fins makes it unlikely that males are involved in egg carrying. The few larvae of C. dewitti caught so far occurred from October onwards. Their size indicates that they have hatched as early as September. This suggests an incubation period of at least six months. We compare this with parental care reported in other notothenioids.

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Kacem, Hichem, and Lassâd Neifar. "The reproductive biology of the grey triggerfish Balistes capriscus (Pisces: Balistidae) in the Gulf of Gabès (south-eastern Mediterranean Sea)." Journal of the Marine Biological Association of the United Kingdom 94, no. 7 (June 17, 2014): 1531–37. http://dx.doi.org/10.1017/s0025315414000824.

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Fundamental information on the reproductive biology of the grey triggerfish Balistes capriscus from the Gulf of Gabès (south-eastern Mediterranean Sea) is based on 751 specimens, collected between June 2005 and May 2010, from commercial catches at different fishing ports at Chebba (34°14′N 11°06′E), Kerkennah (34°45′N 11°17′E) and Zarzis (33°41′N 11°48′E). The species were caught in this area using pelagic trawl nets. The calculation of the gonadosomatic index suggested that the spawning season of grey triggerfish occurred mainly between July and mid-September with a peak in July, coinciding with summer time. The first maturation occurred at 20.26 cm fork length for females and 21.3 cm fork length for males. The monthly values of hepatosomatic index and condition factor (K) indicated that the liver was the most severely stressed organ in the reproduction process of energy transfer. The absolute fecundity (F) ranged from 290,120 to 984,990 eggs per female. The fecundity of the species was determined by the size and weight of the individuals.

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Journal articles on the topic 'Absolute fecundity'

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