Artigos de revistas: "Spawning time"

1

Óskarsson, Guðmundur J., e Christopher T. Taggart. "Spawning time variation in Icelandic summer-spawning herring (Clupea harengus)". Canadian Journal of Fisheries and Aquatic Sciences 66, n.º 10 (outubro de 2009): 1666–81. http://dx.doi.org/10.1139/f09-095.

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Different fish stocks of the same species are defined by spatial and temporal differences in spawning, though spawning time can vary within and among stocks. Here we address spawning time variation in Icelandic summer-spawning (ISS) Atlantic herring ( Clupea harengus ). We do so by examining influencing factors that include variation in stock size structure, spawning experience (recruit vs. repeat spawners), spawning stock biomass (SSB), sea temperature, and combinations thereof. Our results, based on temporal variation in ovary weight (OW), relative ovary weight (RG), and maturation stage, across a time series of nearly 50 years and eight length classes of ISS herring, show that spawning occurs over a relatively invariant 30-day period defined by day-of-the-year. Logistic regression analyses and temporal development in OW and RG show that maximum spawning invariably occurs on day-of-the-year 200 ± 15 days, and seasonal variation in mesenteric fat content is physiologically consistent with the timing. We show that the smaller recruit spawners tend to spawn ~17 days later, on average, than the larger repeat spawners. Spawning occurs ~7 days later when SSB is greater than the long-term average, and spawning may be delayed by as much as 10 days during periods of colder than average ocean temperature.

2

Otterå, H., A.-L. Agnalt, A. Thorsen, O. S. Kjesbu, G. Dahle e K. Jørstad. "Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions". ICES Journal of Marine Science 69, n.º 10 (27 de julho de 2012): 1722–28. http://dx.doi.org/10.1093/icesjms/fss135.

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Abstract Otterå*, H., Agnalt, A-L., Thorsen, A., Kjesbu, O.S., Dahle, G., and Jørstad, K. 2012. Is spawning time of marine fish imprinted in the genes? A two-generation experiment on local Atlantic cod (Gadus morhua L.) populations from different geographical regions. – ICES Journal of Marine Science, 69: 1722–1728. Spawning time (onset of spawning) in Atlantic cod (Gadus morhua L.) was monitored in an experimental setup and combined with modelled spawning time estimates from the wild. The experiment broodstock were collected from several geographical areas and kept in a common environment. Their spawning times in 2004 were compared with the spawning times of their daughters in 2009 and 2010. Daughter spawning time was highly correlated with that of the mother, indicating genetic regulation of spawning time. However, large individual variation in spawning time was observed. The modelling data suggests a north-south gradient in onset of spawning along the Norwegian coast, driven by differences in temperature, i.e. later dates of spawning in the north.

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Blanchfield, P. J., e M. S. Ridgway. "Reproductive timing and use of redd sites by lake-spawning brook trout (Salvelinus fontinalis)". Canadian Journal of Fisheries and Aquatic Sciences 54, n.º 4 (1 de abril de 1997): 747–56. http://dx.doi.org/10.1139/f96-344.

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We provide a detailed description of a salmonine mating system based on daily observations of tagged individuals in a lake-spawning population of brook trout (Salvelinus fontinalis) throughout two breeding seasons. Actual spawning occurred over a period of ~50 d. Over 90% of spawning males were present soon after spawning commenced and outnumbered females for the duration of the spawning period. The amount of time males and females remained on the spawning grounds increased with body size; however, males were present over a longer period than females of equivalent size. A distinct seasonal peak in spawning activity (~15 d) accounted for 58 and 84% (1994 and 1995) of all reproduction and was coincident with a decline in water temperature below 11°C and increased rainfall. Selection of redd sites by female brook trout was determined by groundwater flow which was significantly greater than at nonspawning sites. A preference for certain redd sites was observed, with 50% of spawnings occurring at 11 sites. The construction of multiple redds and duration in spawning activity by females increased with body size. Extensive reuse of redd sites and rapid replacement of females during removal experiments indicate that redd sites are a limiting resource.

4

Slotte, A., A. Johannessen e O. S. Kjesbu. "Effects of fish size on spawning time in Norwegian spring-spawning herring". Journal of Fish Biology 56, n.º 2 (fevereiro de 2000): 295–310. http://dx.doi.org/10.1111/j.1095-8649.2000.tb02107.x.

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FUJIOKA, YASUHIRO, TAKASHI TAGUCHI e TAKESHI KIKKO. "Spawning time, spawning frequency, and spawned egg number in a multiple-spawning fish, the honmoroko Gnathopogon caerulescens". NIPPON SUISAN GAKKAISHI 79, n.º 1 (2013): 31–37. http://dx.doi.org/10.2331/suisan.79.31.

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Jamieson, I. G., D. M. Blouw e P. W. Colgan. "Parental care as a constraint on male mating success in fishes: a comparative study of threespine and white sticklebacks". Canadian Journal of Zoology 70, n.º 5 (1 de maio de 1992): 956–62. http://dx.doi.org/10.1139/z92-136.

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To investigate constraints imposed by male parental behavior on male mating success we compared mate competition in two related 'species' of stickleback, one showing parental care (threespine stickleback, Gasterosteus aculeatus), the other not (white stickleback, Gasterosteus sp.). Three males of each species (tested separately) competed for spawnings with gravid females over a 10-day period. Our findings showed that once a threespine male acquires its first clutch of eggs, the chances of it spawning successively over the next 4 days increase, after which courtship activity declines and parental care of eggs increases. This leads to a serial pattern of spawning amongst the three males in which the second male spawns successively in its nest after the first male has completed its spawnings, followed by the third male, if it spawns at all. However, the third male is more likely to steal fertilizations in the nests of the other two males; stolen fertilizations represented an estimated 29% of the spawning frequency of the third male, compared with 5 and 0% for the second and first males, respectively. The order in which threespine males spawned was correlated with the order in which they initiated nest construction and their ability to defend and maintain a nest site. Immediately after spawning, white stickleback males disperse their eggs among clumps of filamentous algae, where the eggs develop without further parental assistance. In contrast to threespines, white sticklebacks tested under the same competitive conditions showed a random pattern of spawning amongst the three males and stolen fertilizations were not observed. This difference in spawning pattern presumably reflects the time constraint imposed on the sexual phase by the imminent need for parental care once a threespine male obtains eggs. Without the need for parental care of eggs, white males that spawn are not under the same time constraints and therefore each successive spawning is of equal value among competing males, resulting in a random pattern of spawning. In contrast, an asymmetry exists in threespines in which males with freshly spawned eggs in their nest increase their courtship intensity relative to males without eggs, resulting in a serial or ordered pattern of spawning among the males. It is further suggested that stolen fertilizations may be a secondary adaptation to offset any inability to compete effectively for nest sites and females during the initial part of the breeding period.

7

Wu, Lisheng, Qiujing Gao, Guizhong Wang e Yusha Liu. "Diel variations in Centropages tenuiremis (Copepoda) feeding, spawning and its relationship with temperature". Journal of the Marine Biological Association of the United Kingdom 93, n.º 3 (30 de agosto de 2012): 645–49. http://dx.doi.org/10.1017/s0025315412001026.

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Diel rhythms in feeding and spawning were investigated in Centropages tenuiremis from Xiamen Bay in March to May, 2006. Circular statistics were used to determine the peak time of spawning. The results showed that the feeding activities of females were stably higher at night-time, and there was a remarkable earlier shift in spawning peak time with warmer seawater. Thus, the lag times between peak times of gut pigment content and spawning were shortened with the increase of temperature. It suggested that there was a direct effect of feeding rhythms on egg production variations in copepods, and the seawater temperature would work on the converting time and then influence the spawning peak time. So the effect of temperature cannot be ignored in the investigation of the effects of feeding on egg production.

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Hay, D. E. "Tidal Influence on Spawning Time of Pacific Herring (Clupea harengus pallasi". Canadian Journal of Fisheries and Aquatic Sciences 47, n.º 12 (1 de dezembro de 1990): 2390–401. http://dx.doi.org/10.1139/f90-266.

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Dates of over 17 000 records of Pacific herring (Clupea harengus pallasi) spawns from 1951 to 1986 in British Columbia were examined by tidal or lunar phases. The frequency of spawns was significantly higher during neap tides following a new moon. The effect was greatest in spawning areas close to the open Pacific and least in the inside waters of the Strait of Georgia. The mechanism of tidal influence on spawning is uncertain but may involve inhibition of spawning during periods of strong spring tides corresponding to periods of full and new moons. An association between spawning time and tidal phases requires that the annual calendar dates of spawning times change between years. A tidal cycle (or a synodic month) is about 29.6 d, and 12 synodic mo equals 355.4 d, whereas a calendar year is about 365.2 d. Therefore, the dates of tidal phases, such as the springtide, are either about 10 d earlier or 5 d later relative to the previous year. Other possible consequences of tidal influence include the timing of spawning waves and differences in size composition and egg size between waves.

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Muller, E., e M. J. A. Vermeij. "Day time spawning of a Caribbean coral". Coral Reefs 30, n.º 4 (28 de agosto de 2011): 1147. http://dx.doi.org/10.1007/s00338-011-0814-7.

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Forsythe, Patrick S., James A. Crossman, Nora M. Bello, Edward A. Baker e Kim T. Scribner. "Individual-based analyses reveal high repeatability in timing and location of reproduction in lake sturgeon (Acipenser fulvescens)". Canadian Journal of Fisheries and Aquatic Sciences 69, n.º 1 (janeiro de 2012): 60–72. http://dx.doi.org/10.1139/f2011-132.

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Few studies have quantified the repeatability of reproductive decisions by individuals or assessed their relationship with environmental variables over multiple seasons for long-lived iteroparous fish species. Using individual-based data collected for 678 lake sturgeon ( Acipenser fulvescens ) over 8 consecutive years, we evaluated hypotheses regarding spawning periodicity and repeatability of spawning location, spawning time, and environmental cues associated with spawning. At our study site (Upper Black River, northern Michigan, USA), interspawning interval differed between males (2.3 ± 0.08 years) and females (3.7 ± 0.16 years), but was not significantly related to age. Individual spawning behavior was highly repeatable with respect to spawning time (relative day within the spawning season) for both sexes regardless of size or age, but was less repeatable, though still significant, relative to water temperature, river discharge, and lunar phase. Breeding area was also repeatable, with individuals spawning earlier in the season selecting locations further upstream than those spawning later. Repeatability in spawning times and locations suggest that subpopulation differentiation may develop among different spawning groups, even within small and spatially contiguous areas.

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Kurita, Yutaka. "Revised concepts for estimation of spawning fraction in multiple batch spawning fish considering temperature-dependent duration of spawning markers and spawning time frequency distribution". Fisheries Research 117-118 (abril de 2012): 121–29. http://dx.doi.org/10.1016/j.fishres.2011.05.010.

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Starr, Michel, John H. Himmelman e Jean-Claude Therriault. "Environmental Control of Green Sea Urchin, Strongylocentrotus droebachiensis, Spawning in the St. Lawrence Estuary". Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 5 (1 de maio de 1993): 894–901. http://dx.doi.org/10.1139/f93-103.

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Environmental factors and spawning of the green sea urchin, Strongylocentrotus droebachiensis, were examined during 1983 and 1984 in the St. Lawrence Estuary. In both years, spawning occurred in June, which contrasts sharply with the February to early May spawnings reported for other locations. This difference does not appear to be related to temperature, but to the much delayed spring increase of phytoplankton in the Estuary. In both 1983 and 1984, sea urchin spawning coincided with the first marked and sustained increase in phytoplankton abundance (chlorophyll a levels of 1–2 mg∙m−3 for > 3 d) which took place about 2 wk before the main spring bloom; this first increase coincided with a sharp increase in salinity resulting from a decrease in freshwater runoff. Sea urchin spawned later in 1983 than in 1984. This difference did not appear to be related to either a critical temperature level or short-term temperature fluctuations; however, it did coincide with a greater freshwater runoff and a consequently delayed seasonal increase in salinity and phytoplankton. We hypothesize that onset of the phytoplankton bloom initiates spawning; freshwater runoff may indirectly determine the time of spawning by controlling when the bloom will occur.

13

Keith, Sally A., Jeffrey A. Maynard, Alasdair J. Edwards, James R. Guest, Andrew G. Bauman, Ruben van Hooidonk, Scott F. Heron et al. "Coral mass spawning predicted by rapid seasonal rise in ocean temperature". Proceedings of the Royal Society B: Biological Sciences 283, n.º 1830 (11 de maio de 2016): 20160011. http://dx.doi.org/10.1098/rspb.2016.0011.

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Coral spawning times have been linked to multiple environmental factors; however, to what extent these factors act as generalized cues across multiple species and large spatial scales is unknown. We used a unique dataset of coral spawning from 34 reefs in the Indian and Pacific Oceans to test if month of spawning and peak spawning month in assemblages of Acropora spp. can be predicted by sea surface temperature (SST), photosynthetically available radiation, wind speed, current speed, rainfall or sunset time. Contrary to the classic view that high mean SST initiates coral spawning, we found rapid increases in SST to be the best predictor in both cases (month of spawning: R 2 = 0.73, peak: R 2 = 0.62). Our findings suggest that a rapid increase in SST provides the dominant proximate cue for coral mass spawning over large geographical scales. We hypothesize that coral spawning is ultimately timed to ensure optimal fertilization success.

14

Carscadden, J., B. S. Nakashima e K. T. Frank. "Effects of fish length and temperature on the timing of peak spawning in capelin (Mallotus villosus)". Canadian Journal of Fisheries and Aquatic Sciences 54, n.º 4 (1 de abril de 1997): 781–87. http://dx.doi.org/10.1139/f96-331.

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Some characteristics of Newfoundland capelin (Mallotus villosus) changed during 1991-1994. Peak spawning times were later than most years in the 1980s and fish were smaller. These changes occurred during a period of below-normal sea temperatures. We tested the effects of sea temperatures during maturation and mean size of mature fish on peak spawning times using regression analysis and found significant negative relationships for both independent variables. Results of a stepwise regression showed that fish length and sea temperature during maturation were equally important and together explained about 80% of the spawning time variation. We suggest that maturation and migration are closely linked to seasonal warming and the zooplankton cycle. Given the high spawning mortality of capelin, it seems that this linkage favours maximum gonad production rather than adult survival. Knowledge of spring water temperatures would permit some prediction of capelin spawning time. However, the data series for mean length used in this analysis is not useful for predicting spawning time.

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Babcock, R. "Synchronous multispecific spawning on coral reefs: potential for hybridization and roles of gamete recognition". Reproduction, Fertility and Development 7, n.º 4 (1995): 943. http://dx.doi.org/10.1071/rd9950943.

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Problems of gamete recognition in corals and other mass-spawning invertebrates are potentially great. In 'mass spawnings', closely-related species or genera commonly spawn at the same time, or within 1 or 2 h of each other, increasing the potential for hybridization. Among mass-spawning corals, most of the species involved are hermaphrodites that package the gametes in buoyant bundles that float to the sea surface before breaking up. Local hydrodynamic features frequently act to aggregate gametes from many different species into slicks where both eggs and sperm can be viable for extended periods. Other mass-spawning invertebrate taxa, such as molluscs, polychaetes and various echinoderms, do not have buoyant gametes but also spawn with a high level of synchrony. Gametes of organisms participating in these spawning events must be able to successfully recognize conspecifics. If they cannot do this, either through sperm chemotaxis or by mechanisms at the level of sperm binding and penetration, there may be high levels of gamete wastage through hybridization. Alternatively, viable hybrids may be formed, a factor that could have contributed to the evolutionary history of mass-spawning taxa, as well as to the taxonomic difficulties that have plagued the taxonomy of groups such as reef-building corals. Within some mass-spawning taxa, pre-zygotic barriers to fertilization suggest relatively recent molecular evolution at gamete recognition loci.

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Óskarsson, G. J., O. S. Kjesbu e A. Slotte. "Predictions of realised fecundity and spawning time in Norwegian spring-spawning herring (Clupea harengus)". Journal of Sea Research 48, n.º 1 (agosto de 2002): 59–79. http://dx.doi.org/10.1016/s1385-1101(02)00135-1.

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Burt, Austin, Wayne Hunte e France Dufresne. "Identifying the time scale of temporal association". Canadian Journal of Zoology 66, n.º 9 (1 de setembro de 1988): 2090–92. http://dx.doi.org/10.1139/z88-309.

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Previously used methods of investigating the temporal association of behavioural events have tested sequences of events for temporal clumping; such an approach does not quantitatively indicate the time scale over which the association is significant. We present a novel method of analysis that specifically identifies this time scale, thereby allowing more ready elimination of competing causal hypotheses for the association observed. Our null hypothesis is that, following any event, the number of events in a given time interval is independent of the time elapsed since the initial event. The method is simple and robust against long-term changes in event frequency, and provides a more detailed quantitative description of the temporal association. We illustrate it using data on spawning in the blueheaded wrasse (Thalassoma bifasciatum). The analysis demonstrates that, after a spawning event, there is a 70% increase in mean spawning frequency which lasts for 30 s and then abruptly disappears. The effect of spawns appears to summate multiplicatively.

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Gordoa, Ana, Maria Pilar Olivar, Raquel Arevalo, Jordi Viñas, Balbina Molí e Xenia Illas. "Determination of Atlantic bluefin tuna (Thunnus thynnus) spawning time within a transport cage in the western Mediterranean". ICES Journal of Marine Science 66, n.º 10 (11 de agosto de 2009): 2205–10. http://dx.doi.org/10.1093/icesjms/fsp211.

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Abstract Gordoa, A., Olivar, M. P., Arevalo, R., Viñas, J., Molí, B., and Illas, X. 2009. Determination of Atlantic bluefin tuna (Thunnus thynnus) spawning time within a transport cage in the western Mediterranean. – ICES Journal of Marine Science, 66: 2205–2210. For the first time, tuna spawning in a transport cage being towed from the western Mediterranean spawning ground to a fattening facility off the coast of northeastern Spain was examined during the 2008 fishing season. Daylight and night surface plankton samples were collected using bongo nets located in front of and behind the transport cage. The results for the different time intervals revealed clear and massive nocturnal spawning from 03:00 to 05:00, when the rear bongo was completely jammed with eggs (up to 250 000–300 000 eggs per 1000 m3). Egg size and morphology were consistent with the features of Thunnus thynnus eggs, and identification was confirmed by genetic analysis. Microscopic examination showed the eggs to be in the very early developmental stages. Spawning took place every night over the entire journey. The study showed that neither captivity nor handling/environmental changes along the route inhibited T. thynnus spawning to a very precise biological clock. The study also revealed the diel temporal concurrence of T. thynnus spawning and jellyfish larvae at the sea surface.

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Rajasilta, Marjut. "Relationship between Food, Fat, Sexual Maturation, and Spawning Time of Baltic Herring (Clupea harengus membras) in the Archipelago Sea". Canadian Journal of Fisheries and Aquatic Sciences 49, n.º 4 (1 de abril de 1992): 644–54. http://dx.doi.org/10.1139/f92-073.

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The effect of nutritional status on gonad maturation and timing of spawning was examined in the Baltic herring (Clupea harengus membras) in the Archipelago Sea. Fish were collected from overwintering areas in December and from the spawning grounds in May–July. Muscle fat content, amount of mesenteric fat, and condition factor were used as indicators of nutritional status of fish. In winter, fish were highly variable with substantial individual variation in nutritional status, gonad stage, gonad weight, and gonadosomatic index (GSI). Gonad weight was related to fat content, suggesting a close relationship with fish nutritional status and maturation rate. Spawning fish were separable into early and late spawners according to fat content, gonad weight, and GSI but not according to length. The spawning shoals consisted of mixtures of fish of all sizes. I concluded that in the study area, individual maturation cycles vary and timing of spawning is primarily determined by the feeding conditions prior to spawning.

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Soong, K., Y. Lin, S. Chao e D. Chang. "Spawning time of two shallow-water brittle stars". Marine Ecology Progress Series 376 (11 de fevereiro de 2009): 165–71. http://dx.doi.org/10.3354/meps07804.

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Duong, Thuy Yen, Kim T. Scribner, James A. Crossman, Patrick S. Forsythe e Edward A. Baker. "Environmental and maternal effects on embryonic and larval developmental time until dispersal of lake sturgeon (Acipenser fulvescens)". Canadian Journal of Fisheries and Aquatic Sciences 68, n.º 4 (abril de 2011): 643–54. http://dx.doi.org/10.1139/f2011-008.

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For migratory fish like lake sturgeon ( Acipenser fulvescens ), the period from egg deposition through embryonic and larval development until dispersal (ELDTUD) contributes substantially to variation in survival at the individual level and to population levels of recruitment. Using genetically determined parentage, we examined the relative importance of environmental variables in a stream environment (e.g., temperature and discharge) and maternal effects (including individual female body size, spawning time, and location) to ELDTUD on an individual basis. Adult lake sturgeon (n = 208) spawning in the Upper Black River (Michigan, USA), and larvae (n = 1444) dispersing downstream were captured during the 2007 spawning season. We used generalized mixed models and multimodel inference based on Kullback–Leibler information-theoretic criteria to demonstrate that environmental variables and the maternal effects of individual female and spawning time were both important predictors of ELDTUD. Decreasing ELDTUD during the season resulted from linearly increasing temperature and nonlinearly decreasing river discharge. Spawning time and individual female explained a large proportion of variation in ELDTUD. The individual-based approach used in this study provided precise estimates of ELDTUD and also facilitated the partitioning of variation in ELDTUD of larvae produced by the same female and among females spawning at different times and different environmental conditions.

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Polat, Hamza, Rafet Cagri Ozturk, Yahya Terzi, Ilhan Aydin e Ercan Kucuk. "Effect of Photoperiod Manipulation on Spawning Time and Performance of Turbot (Scophthalmus maximus)". Aquaculture Studies 21, n.º 3 (13 de março de 2021): 109–15. http://dx.doi.org/10.4194/2618-6381-v21_3_03.

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Temperature and photoperiod are known as the main stimuli of seasonal reproduction in fish. Turbot (Scophthalmus maximus) is a spring spawning teleost fish species with a promising aquaculture potential and high market value. This study was conducted to assess the effect of photoperiod manipulation on spawning time and spawning performance of turbot. A total of 28 mature turbots from the Black Sea population were subjected to manipulated photoperiod (a photoperiod regime that fish would naturally receive three months later) and natural photoperiod for almost a year. While the fish exposed to natural photoperiod spawned in May, the fish exposed to manipulated photoperiod spawned almost three months earlier compared to the natural photoperiod group. Reproductive and hatchery performance of the manipulated photoperiod and natural photoperiod groups were similar. It can be emphasized that photoperiod play an important role in accelerating maturation and spawning. The findings of this study could be implemented in the turbot aquaculture industry to advance production.

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Young, Jock, Anita Drake, Michael Brickhill, Jessica Farley e Thor Carter. "Reproductive dynamics of broadbill swordfish, Xiphias gladius, in the domestic longline fishery off eastern Australia". Marine and Freshwater Research 54, n.º 4 (2003): 315. http://dx.doi.org/10.1071/mf02011.

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The reproductive ecology of broadbill swordfish, Xiphias gladius, was evaluated based on 1437 fish (size range 50–300 cm orbital fork length [OFL]) caught in the domestic longline fisheries off eastern Australia and New Zealand between May 1999 and March 2001. Reproductive activity was assessed using histology, a gonadosomatic index, and maximum oocyte size. Males were significantly smaller than females and represented less than one third of the sampled fish. Sex ratio differed significantly with respect to fish size and time of year. Females began maturing at 150-cm OFL and spawned from September to March, with the greatest activity from December to February. Males matured at 90-cm OFL; ripe males were found from January to March, but also in May and October, suggesting an extended reproductive period. During the spawning period the proportion of spawning to inactive mature sized females was significantly higher in waters west of longitude 158°E than in waters to the east. Further to the east, samples taken from the New Zealand fishery showed no actively spawning fish during the main spawning period. Females were increasingly reproductively active as water temperature increased beyond 24°C and sea surface chlorophyll a decreased below 0.2 μg L–1. Batch fecundity was linearly related to fish length with a mean batch fecundity of 1.66 million oocytes for females ranging in size from 173- to 232-cm OFL. The presence of hydrated oocytes and post-ovulatory follicles (POFs) in the same ovaries indicated multiple spawnings. Depending on the time taken for POFs to degrade, these may have been daily at the height of the spawning season.

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Beacham, Terry D., e Clyde B. Murray. "Comparative Developmental Biology of Chum Salmon (Oncorhynchus keta) from the Fraser River, British Columbia". Canadian Journal of Fisheries and Aquatic Sciences 43, n.º 2 (1 de fevereiro de 1986): 252–62. http://dx.doi.org/10.1139/f86-032.

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Eggs and alevins from 32 families of chum salmon (Oncorhynchus keta) from seven Fraser River stocks spawning at different times or in different tributaries were incubated in controlled water temperatures of 4, 8, and 12 °C. There were significant differences in egg and alevin survival among stocks and among families within stocks in the different incubation temperatures. Highest egg survival for a late-spawning Vedder River stock occurred at 4 °C, while egg survival from other stocks was highest at 8 °C. Late-spawning stocks had smaller eggs and earlier times of fry emergence than did early-spawning ones. There was no effect of spawning time on alevin hatching time. Alevins hatching at 8 °C were larger than those hatching at 4 or 12 °C, but there were no stock differences in alevin length or tissue weight. Stocks with greater egg sizes produced alevins of greater total weight. Fry emerging at 8 °C were larger than those emerging at 4 or 12 °C, and fry from early-spawning stocks were longer and had greater tissue weight than those from late-spawning ones. There were significant differences among families within stocks in size of alevins and fry, and family differences should be accounted for in studies of salmonid developmental biology.

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Secor, David H., Michael H. P. O’Brien, Benjamin I. Gahagan, Dewayne A. Fox, Amanda L. Higgs e Jessica E. Best. "Multiple spawning run contingents and population consequences in migratory striped bass Morone saxatilis". PLOS ONE 15, n.º 11 (25 de novembro de 2020): e0242797. http://dx.doi.org/10.1371/journal.pone.0242797.

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Multiple spawning run contingents within the same population can experience varying demographic fates that stabilize populations through the portfolio effect. Multiple spawning run contingents (aka run timing groups) are reported here for the first time for striped bass, an economically important coastal species, which is well known for plastic estuarine and shelf migration behaviors. Adult Hudson River Estuary striped bass (n = 66) were tagged and tracked with acoustic transmitters from two known spawning reaches separated by 90 km. Biotelemetry recaptures for two years demonstrated that each river reach was associated with separate contingents. Time series of individual spawning phenologies were examined via nonparametric dynamic time warping and revealed two dominant time series centroids, each associated with a separate spawning reach. The lower spawning reach contingent occurred earlier than the higher reach contingent in 2017 but not in 2018. The majority (89%) of returning adults in 2018 showed the same contingent behaviors exhibited in 2017. Spawning contingents may have been cued differently by temperatures, where warming lagged 1-week at the higher reach in comparison to the lower reach. The two contingents exhibited similar Atlantic shelf migration patterns with strong summer fidelity to Massachusetts Bay and winter migrations to the southern US Mid-Atlantic Bight. Still, in 2017, differing times of departure into nearby shelf waters likely caused the early lower reach contingent to experience substantially higher mortality than the later upper reach contingent. Anecdotal evidence suggests that higher fishing effort is exerted on the early-departing individuals as they first enter shelf fisheries. Thus, as in salmon, multiple spawning units can lead to differential demographic outcomes, potentially stabilizing overall population dynamics.

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Heggberget, Tor G. "Timing of Spawning in Norwegian Atlantic Salmon (Salmo salar)". Canadian Journal of Fisheries and Aquatic Sciences 45, n.º 5 (1 de maio de 1988): 845–49. http://dx.doi.org/10.1139/f88-102.

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A hypothesis that thermal regime regulates the timing of spawning in Atlantic salmon (Salmo salar) was analysed by correlating time of commencement and peak of spawning in 16 Norwegian streams with temperature, latitude, and stream flow. Only temperature during incubation of the eggs proved to have any statistically significant effect. Since the duration of egg incubation is known to depend on temperature regime (i.e. on degree-days), a similar linking of spawning time to stream temperature allows spawning to occur at a time which will result in hatching of eggs at a specific and presumably optimal time for survival of fry.

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Page, Fred H., e Kenneth T. Frank. "Spawning Time and Egg Stage Duration in Northwest Atlantic Haddock (Melanogrammus aeglefinus) Stocks with Emphasis on Georges and Browns Bank". Canadian Journal of Fisheries and Aquatic Sciences 46, S1 (19 de dezembro de 1989): s68—s81. http://dx.doi.org/10.1139/f89-279.

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Literature data was used to examine the hypothesis that variation in the spawning time, defined as the peak in egg abundance, of Northwest Atlantic haddock (Melanogrammus aeglefinus) stocks is explained by water temperature and to derive calibration curves relating incubation temperature to haddock egg stage duration. Spawning times occurred, on average, in March on Georges Bank, late April/early May on Browns Bank, and in June/July on the Grand Banks. Temperatures at peak spawning overlapped considerably but differed in terms of phase in the annual temperature cycle. Inter-annual variation in spawning time of Georges Bank haddock varied by 3 mo and was significantly correlated with water temperature. Browns Bank haddock spawning varied by only 1 mo and was not correlated with water temperature. Egg stage duration varied with incubation temperature. A power curve best described the relationship and was used to estimate the historical, annual variation in haddock egg stage duration which ranged from 10 to 20 d (mean = 16 d) on Georges Bank and from 10 to 30 d (mean = 18 d) on Browns Bank during 1946–80. Collectively, our analysis calls into question the generality of the assumption of constant spawning times for marine fish species and provides essential information for field measurement of haddock egg production rates, mortality, advection, and dispersal.

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Mayes, Kevin B., Paul M. Rosenblum e Thomas M. Brandt. "Raceway Spawning of Florida Largemouth Bass: Effects of Acclimation Time and Hormone Treatment on Spawning Success". Progressive Fish-Culturist 55, n.º 1 (janeiro de 1993): 1–8. http://dx.doi.org/10.1577/1548-8640(1993)055<0001:rsoflb>2.3.co;2.

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Hutchings, Jeffrey A., e Ransom A. Myers. "Effect of Age on the Seasonality of Maturation and Spawning of Atlantic Cod, Gadus morhua, in the Northwest Atlantic". Canadian Journal of Fisheries and Aquatic Sciences 50, n.º 11 (1 de novembro de 1993): 2468–74. http://dx.doi.org/10.1139/f93-271.

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Analysis of 46 yr of research trawl survey data from seven regions in the Northwest Atlantic (Newfoundland and Labrador) indicated that older individuals of Atlantic cod, Gadus morhua, of both sexes initiated and completed spawning later, and spawned for a greater length of time, than younger individuals. Within regions, males were in spawning condition for longer periods than females. Among regions, spawning duration of males (age = 11 yr) averaged 43.5 ± 13.6 d and was significantly longer than that of females (age = 11 yr; 25.2 ± 8.4 d). The strong association between age and time of spawning provides empirical evidence of size-specific, assortative mating in cod. The decline in recruitment of cod in NAFO Division 2J3KL since 1962 is associated with a dramatic reduction in the fecundity contribution of older (15–20 yr) relative to younger (7–9 yr) individuals. Our results indicate that this increase in proportional abundance of younger individuals should be concomitant with a decline in the duration of spawning time, reducing the probability that larval emergence will match peak abundances of zooplankton. Thus, age dependence of maturation and spawning times provides a mechanism by which size-selective mortality against larger, older individuals can increase variability in recruitment in Atlantic cod.

30

Danzmann, Roy G., Moira M. Ferguson e David M. Heculuck. "Heterogeneity in the Distribution of Mitochondrial DNA Haplotypes in Female Rainbow Trout Spawning in Different Seasons". Canadian Journal of Fisheries and Aquatic Sciences 51, S1 (19 de dezembro de 1994): 284–89. http://dx.doi.org/10.1139/f94-315.

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Analysis of females spawning throughout the year (October to late February) at a commercial fish farm in Ontario, revealed significant heterogeneity in the distribution of their mitochondrial DNA (mtDNA) haplotypes. These findings are consistent with previous data from this stock and indicate that female– daughter spawning times are temporally stable. This suggests a high maternal genetic contribution to this trait. Conversely, no temporal heterogeneity in the spawning times of females with different mtDNA haplotypes was observed in an unselected government (Ontario Ministry of Natural Resources) hatchery stock recently derived from a wild naturalized population. The government hatchery stock is normally spring spawning and has much higher levels of nucleon diversity compared with the cultured stock. Therefore, it appears that only a limited number of family lines within unselected stocks may show the propensity towards greatly accelerated spawning times. Furthermore, associations between spawning time and mtDNA haplotype may only become apparent following several generations of artificial selection.

31

Otterå, Håkon, Ann-Lisbeth Agnalt e Knut E. Jørstad. "Differences in spawning time of captive Atlantic cod from four regions of Norway, kept under identical conditions". ICES Journal of Marine Science 63, n.º 2 (1 de janeiro de 2006): 216–23. http://dx.doi.org/10.1016/j.icesjms.2005.11.004.

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Abstract Several hundred Atlantic cod (Gadus morhua L.) were collected from selected spawning grounds along the Norwegian coast in March 2002. Four areas or regions that represent a wide range of environmental conditions were chosen for our breeding experiments: Porsangerfjord, Tysfjord, Helgeland, and Øygarden. Cod were transported to Øygarden near Bergen, individually tagged, and kept in sea cages. In both 2003 and 2004, a total of 40 family groups (adult pairs) representing the four regions were monitored for their spawning performance in separate tanks. During the spawning period, the quantity and diameter of eggs were recorded. During 2003, the time of peak spawning differed among groups. It was evident that the broodstock from the Øygarden region spawned about one month earlier than the broodstock collected from the Helgeland region. This also occurred in 2004, two years after the cod were collected, suggesting that the difference has a genetic component. Differences in life history parameters between cod populations, such as spawning cycles as described here, could be adaptive and under genetic control. This must be taken into consideration when assessing precautionary means of overcoming the problem with escapees from future cod mariculture.

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Hayes, John W. "Competition for Spawning Space Between Brown (Salmo trutta) and Rainbow Trout (S. gairdneri) in a Lake Inlet Tributary, New Zealand". Canadian Journal of Fisheries and Aquatic Sciences 44, n.º 1 (1 de janeiro de 1987): 40–47. http://dx.doi.org/10.1139/f87-005.

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Effect of interference competition for spawning space on spawning success of brown (Salmo trutta) and rainbow trout (S. gairdneri) was studied in the main spawning tributary of Lake Alexandrina, New Zealand. Competition was mediated through redd superimposition and severely limited the spawning success of both species. Overall spawning success, from egg deposition to fry emergence, was 2.1% for rainbow trout and 0.2% for brown trout and was dependent on time of spawning. Brown trout spawned from April to June and rainbow trout spawned from April to October. Brown trout and early spawning rainbow trout experienced poor spawning success due to severe redd superimposition by later spawning rainbows. Late spawning rainbows experienced highest spawning success. Redd superimposition by rainbow trout caused a 94% reduction in spawning success of brown trout in an experimental section of stream. Severe intraspecific competition for spawning space, through redd super-imposition, determined pattern and timing of peak rainbow fry emergence.

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Sinnatamby, R. Niloshini, Madalena C. Pinto, Fiona D. Johnston, Andrew J. Paul, Craig J. Mushens, Jim D. Stelfox, Hillary G. M. Ward e John R. Post. "Seasonal timing of reproductive migrations in adfluvial bull trout: an assessment of sex, spawning experience, population density, and environmental factors". Canadian Journal of Fisheries and Aquatic Sciences 75, n.º 12 (dezembro de 2018): 2172–83. http://dx.doi.org/10.1139/cjfas-2017-0542.

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Using individual tags combined with a fish fence operated at the mouth of Smith-Dorrien Creek, the primary spawning habitat for Lower Kananaskis Lake bull trout (Salvelinus confluentus), we approximated a complete census of the spawning population from 1996 to 2000 to assess whether timing of upstream and downstream spawning migrations varied with extrinsic and intrinsic factors. The timing of both upstream and downstream migrations varied with sex, previous spawning experience, density, and temperature. Inferred spawning duration based on the predicted upstream and downstream migration dates indicated that experienced female spawners spent the least amount of time upstream and first-time spawners spent the most time upstream. No consistent differences in upstream migration timing were observed between non-repetitive and repetitive spawners. We suggest that variations in spawning migration timing observed in Lower Kananaskis Lake may be linked to environmental factors that influence upstream swimming ability and acquisition and expenditure of energy with respect to reproduction.

34

Thiem, J. D., D. Hatin, P. Dumont, G. Van Der Kraak e S. J. Cooke. "Biology of lake sturgeon (Acipenser fulvescens) spawning below a dam on the Richelieu River, Quebec: behaviour, egg deposition, and endocrinology". Canadian Journal of Zoology 91, n.º 3 (março de 2013): 175–86. http://dx.doi.org/10.1139/cjz-2012-0298.

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Knowledge of the reproductive biology of wild sturgeon populations is critical to ensure the survival of this unique group of animals. We combined gill-netting surveys, nonlethal blood sampling, radiotelemetry, and egg collection to examine the reproductive biology of lake sturgeon (Acipenser fulvescens Rafinesque, 1817) at a suspected spawning ground below a dam on the Richelieu River, Quebec. Lake sturgeon were present at the beginning of sampling in early May, and spawning took place from 26 May to 5 June when water temperature averaged 13.4 ± 0.1 °C (range 11.5–15.5 °C). Daily spawning population estimates ranged from 285 to 1282 individuals and the sex ratio of spawners was estimated at 2.1 males per female. The presence of radio-tagged individuals on the spawning grounds peaked from 20 to 28 May, corresponding with known spawning bouts. Residence time of spawners on the spawning ground ranged from 1 to 27 days (median = 5 days) and there were no differences in residence time between sexes. Nonlethal blood sampling enabled the quantification of steroid levels to determine the spawning population sex ratio, and steroid levels were highest before spawning was known to occur and decreased concurrently with, and after, known spawning events.

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Junquera, S., E. Román, J. Morgan, M. Sainza e G. Ramilo. "Time scale of ovarian maturation in Greenland halibut (Reinhardtius hippoglossoides, Walbaum)". ICES Journal of Marine Science 60, n.º 4 (1 de janeiro de 2003): 767–73. http://dx.doi.org/10.1016/s1054-3139(03)00073-0.

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Abstract Evidence for a prolonged ovarian development phase in Greenland halibut is presented. The reproductive cycle in this species was originally described based on the assumption that this phase should last about one year. The results of the present study, which involves data series covering a long time period and different geographic areas, show instead that there is more than one year between the mean age of the females that are at the onset of ovarian development and the mean age of the females that are actually spawning. There are two possible interpretations for this observation. One is that the ovarian development phase (vitellogenesis) could last more than one year and thus as a consequence, individual spawning would not necessarily occur on an annual basis. The other would be the existence of a high proportion of non-spawning females every year for other reasons not related with the natural rhythm of oocyte development.

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Punt, André E., David C. Smith, Malcolm Haddon, Sarah Russell, Geoffrey N. Tuck e Tim Ryan. "Estimating the dynamics of spawning aggregations using biological and fisheries data". Marine and Freshwater Research 67, n.º 3 (2016): 342. http://dx.doi.org/10.1071/mf14342.

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Acoustic surveys can provide accurate estimates of biomass at a particular location at a point in time, but provide a negatively biased estimate of the total spawning population unless the proportion of fish that are unavailable to the survey is accounted for. Changes to the ages and maturity stages of fish caught during the spawning season is evidence for turnover of fish during spawning and, along with information on relative abundance, provides a basis for estimating turnover rates. A model is therefore developed that tracks the numbers of males and females by age as they arrive on the spawning grounds, initiate spawning, complete spawning and leave the spawning grounds. This model can be used to determine the proportion of the spawning biomass on the spawning grounds over the spawning season. It is applied to data for blue grenadier, Macruronus novaezelandiae, off western Tasmania, Australia. The results can be used to estimate the average proportion of the population available to an acoustic survey, although this estimate is not likely to be very precise, owing to the high between-year variation in arrival times. However, the model provides a quantitative estimate of turnover rate that was previously not available, and is a rigorous basis for estimating turnover for stock assessment.

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Dickey-Collas, Mark, Richard D. M. Nash e Juan Brown. "The location of spawning of Irish Sea herring (Clupea harengus)". Journal of the Marine Biological Association of the United Kingdom 81, n.º 4 (agosto de 2001): 713–14. http://dx.doi.org/10.1017/s0025315401004489.

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Time series of ichthyoplankton surveys targeted at herring larvae describe the distribution of spawning in the north Irish Sea by mapping the occurrence of very young larvae. The surveys suggest, that like other herring stocks, the spawning grounds of Irish Sea herring vary over the years. Currently, spawning at the Mourne location is greatly reduced whereas spawning has occurred at a newly described site to the north of the Isle of Man (off the Point of Ayre). Whilst spawning is dominated by autumn spawners in late September, some spawning occurs through to January.

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Coello, S. "Time of day of spawning in Sardinops sagax (Jenyns)". Journal of Fish Biology 33, n.º 4 (outubro de 1988): 655–56. http://dx.doi.org/10.1111/j.1095-8649.1988.tb05508.x.

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Rustadi, Rustadi. "PENGAMBILAN TELUR DARI INDUK NILA MERAH (Oreochromis sp.) PENGARUHNYA TERHADAP KECEPATAN BERPIJAH KEMBALI". Jurnal Perikanan Universitas Gadjah Mada 1, n.º 1 (26 de janeiro de 1996): 27. http://dx.doi.org/10.22146/jfs.8845.

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Removing eggs from red nila female during spawning period were observed to know an appropriate time of removal and its effect on inter-spawning period of female broodstock. Spawning experiment was conducted with three replicates in the hapa. The female that cared fertilized eggs were cathed on 7th day, 21th, 28th day, and 35th day after stocking. Other spawning experiment with three relications were cared out to test the effect of removing eggs. On 7th day after spawning produced the highest number of spawned female reduced yhe inter-spawning interval, but there was no effect of male stocking on re-spawning rate of female. The low number of eggs per spawner together with asynchronus spawning would be problems faced on mass production of red nila seed.

40

Sundby, Svein, e Odd Nakken. "Spatial shifts in spawning habitats of Arcto-Norwegian cod related to multidecadal climate oscillations and climate change". ICES Journal of Marine Science 65, n.º 6 (2 de junho de 2008): 953–62. http://dx.doi.org/10.1093/icesjms/fsn085.

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Abstract Sundby, S., and Nakken, O. 2008. Spatial shifts in spawning habitats of Arcto-Norwegian cod related to multidecadal climate oscillations and climate change. – ICES Journal of Marine Science, 65: 953–962. Arcto-Norwegian cod tend to produce strong year classes in warm years and poor year classes in cold years. This work shows that spawning intensity at various spawning sites along 1500 km of Norwegian coast is also influenced by climate variations. However, while the recruitment response to temperature is immediate and on an interannual time-scale, the response to changes in spawning site is slower, on a multidecadal time-scale. There have been two cold and two warm periods during the 20th century, cold from 1900 to 1920, warm from 1930 to 1950, cold from 1960 to 1970, and warm since the mid-1980s. A time-series for 1900–1976 on cod roe indices along the coast shows that the southernmost spawning areas are more important during cold periods, and the northernmost ones in warm periods, and coincide with high population fecundity. After 1976, qualitative observations show that there have been poor spawning fisheries in the southernmost spawning areas during the present warm period. From 2003, spawning has been observed along the coast of East Finnmark where it did not transpire during the previous 40 years.

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Skaret, Georg, e Aril Slotte. "Herring submesoscale dynamics through a major spawning wave: duration, abundance fluctuation, distribution, and schooling". ICES Journal of Marine Science 74, n.º 3 (25 de outubro de 2016): 717–27. http://dx.doi.org/10.1093/icesjms/fsw180.

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In this study, a series of 17 repeated acoustic trawl surveys within a ca. 1500 km2 area covering the major spawning location for Norwegian spring-spawning herring (Clupea harengus) was conducted over a period of about 1 month. Local herring abundance increased from ca. 25 000 to 237 000 t, a significant proportion of the total spawning stock, in just 3 d and subsequently decreased to <30 000 t over the next 7 d. The abundance change was due to a single major spawning wave developing over the observation period, and an estimated 46 000 t of eggs and milt were deposited during the short time spent at the spawning ground. There was no difference in spawning activity between day and night, but herring were more associated with deep trenches and also generally stayed deeper in more dense schools during daylight than night-time. Schooling behaviour and distribution were also strongly state-dependent, and both school swimming depth and school height decreased as spawning progressed, as did the bottom depth where the schools were located. The massive herring spawning events seem to be low-risk adaptations to an environment where predators are abundant, with rapid spawning in huge aggregations as a strategy for predator swamping.

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Mohamad, Faridah, Muhd Fawwaz Afham Mohd Sofa, Azwarfarid Manca, Noraznawati Ismail, Zaidi Che Cob e Amirrudin B. Ahmad. "Nests placements and spawning in the endangered horseshoe crab Tachypleus tridentatus (Leach, 1819) (Merostomata: Xiphosurida: Limulidae) in Sabah, Malaysia". Journal of Crustacean Biology 39, n.º 6 (10 de outubro de 2019): 695–702. http://dx.doi.org/10.1093/jcbiol/ruz070.

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Abstract Horseshoe crab populations are declining worldwide, and Tachypleus tridentatus (Leach, 1819) has recently been classified as Endangered in the IUCN Redlist. Among the keys for species survival is successful reproduction. Although there are reports on the reproduction, particularly details on the spawning behaviour, of the American species, Limulus polyphemus (Linnaeus, 1758), information on Southeast Asia species is very scant. This field study reports the nesting activities of T. tridentatus at Jambongan Island, Sabah, Malaysia. Observation were carried out on 16 spawning pairs that were spotted during full and new moon from April-July 2016 in Sabah. Nest placements, number of nests, number of eggs, time spent at each nest, and nest widths, depth, and distance from the highest tide line were recorded for each pair. Tachypleus tridentatus generally laid an average of 967 ± 54.1 eggs/nest (171–2,282) in as many as nine nests on the intertidal zone between 125 and 940 cm from the highest tide. The first nest was dug once the tide began rising, followed by the consecutive nests towards the highest tide line with nest depths ranging between 13 and 22 cm. The complete spawning session (first nest to the last) ended in less than two hours. Time spent in spawning correlates positively with the number of nests and the total number of eggs laid by each spawning female. The spawning area, which is made up mainly by fine and medium-size sediment grains, also experience stable temperature, salinity, and dissolved oxygen conducive for egg-laying and larval development for successful reproduction. The details of spawning are important for planning successful future conservation initiatives for the species, especially in tropical regions.

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Cavada-Blanco, Francoise, Ainhoa L. Zubillaga e Carolina Bastidas. "Microphytoplankton variations during coral spawning at Los Roques, Southern Caribbean". PeerJ 4 (17 de março de 2016): e1747. http://dx.doi.org/10.7717/peerj.1747.

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Phytoplankton drives primary productivity in marine pelagic systems. This is also true for the oligotrophic waters in coral reefs, where natural and anthropogenic sources of nutrients can alter pelagic trophic webs. In this study, microphytoplankton assemblages were characterized for the first time in relation to expected coral spawning dates in the Caribbean. A hierarchical experimental design was used to examine these assemblages in Los Roques archipelago, Venezuela, at various temporal and spatial scales for spawning events in both 2007 and 2008. At four reefs, superficial water samples were taken daily for 9 days after the full moon of August, including days before, during and after the expected days of coral spawning. Microphytoplankton assemblages comprised 100 microalgae taxa at up to 50 cells per mL (mean ± 8 SD) and showed temporal and spatial variations related to the coral spawning only in 2007. However, chlorophyllaconcentrations increased during and after the spawning events in both years, and this was better matched with analyses of higher taxonomical groups (diatoms, cyanophytes and dinoflagellates), that also varied in relation to spawning times in 2007 and 2008, but asynchronously among reefs. Heterotrophic and mixotrophic dinoflagellates increased in abundance, correlating with a decrease of the diatomCerataulina pelagicaand an increase of the diatomRhizosolenia imbricata. These variations occurred during and after the coral spawning event for some reefs in 2007. For the first time, a fresh-water cyanobacteria species ofAnabaenawas ephemerally found (only 3 days) in the archipelago, at reefs closest to human settlements. Variability among reefs in relation to spawning times indicated that reef-specific processes such as water residence time, re-mineralization rates, and benthic-pelagic coupling can be relevant to the observed patterns. These results suggest an important role of microheterotrophic grazers in re-mineralization of organic matter in coral reef waters and highlight the importance of assessing compositional changes of larger size fractions of the phytoplankton when evaluating primary productivity and nutrient fluxes.

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Babcock, Russ, Elke Franke e Neill Barr. "Does spawning depth affect fertilization rates? Experimental data from the sea star Coscinasterias muricata". Marine and Freshwater Research 51, n.º 1 (2000): 55. http://dx.doi.org/10.1071/mf98132.

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Measurements of fertilization rates in free-spawning marine invertebrates have shown that reproductive success is related to both behavioural and environmental factors. Water depth has been suggested as being one such factor affecting fertilization success. In experimental spawnings of the sea star Coscinasterias muricata, fertilization rates decreased exponentially with distance from sperm source but were frequently greater than 20% at distances >10 m downstream. Current speed did not have a significant effect on fertilization rate over the range of velocities examined. Fertilization rates directly downstream from spawning individuals were higher in shallow water (<1 m) than in deep water (>5 m). Diffusion models using empirically derived site-dependent diffusion parameters supported these findings but suggested that this would only be true for eggs released directly downstream from a sperm source. Once lateral diffusion of sperm was accounted for, the model predicted little overall difference in fertilization rates for shallow and deep spawners. These results from Coscinasterias indicate that movements into shallow water at the time of spawning, which have been reported in several asteroid species, may provide little reproductive advantage in environments experiencing net flow conditions.

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Hruska, Kimberly A., Scott G. Hinch, David A. Patterson e Michael C. Healey. "Egg retention in relation to arrival timing and reproductive longevity in female sockeye salmon (Oncorhynchus nerka)". Canadian Journal of Fisheries and Aquatic Sciences 68, n.º 2 (fevereiro de 2011): 250–59. http://dx.doi.org/10.1139/f10-153.

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Some female Pacific salmon ( Oncorhynchus spp.) arrive at spawning grounds but fail to complete spawning prior to death. One hypothesis regarding egg retention is that some individuals do not have sufficient time on spawning grounds for successful completion of spawning. We investigated this hypothesis by quantifying the relationships among arrival timing, reproductive longevity, and egg retention in female sockeye salmon ( Oncorhynchus nerka ) from Weaver Creek Spawning Channel (British Columbia, Canada) in 2006. 250 females were tagged over three sampling periods and followed until death. Earlier-arriving females lived longer than later-arriving females (p < 0.001), but patterns of egg retention were not different across sampling dates (p > 0.40). Complete spawners tended to establish a redd sooner after arrival than incomplete spawners (p = 0.001); there was no relationship between spawning completion and reproductive maturity or fork length (p > 0.30). Consistent with the time limitation hypothesis, females retained a lower proportion of eggs with increasing reproductive longevity. Several long-lived females (>7 days) failed to spawn completely before death, indicating that time limitation was not a factor for spawning success in all females. Further research examining the role of individual-specific behavioural physiology on egg retention in sockeye salmon is needed.

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Zuev, G. V., e T. N. Klimova. "Long-term dynamic of reproductive performance of European anchovy Engraulis encrasicolus Linnaeus, 1758 and its connection with temperature". Marine Biological Journal 2, n.º 2 (30 de junho de 2017): 3–19. http://dx.doi.org/10.21072/mbj.2017.02.2.01.

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European anchovy (Engraulis encrasicolus Linnaeus, 1758) is one of the most numerous species of fish in the Azov-Black Sea basin. It is the main commercial fishery object, its share being about 80 %. Assessment of the functional state of the anchovy population and its dynamics in conditions of the climatic warming was one of the topical tasks in contemporary research. The paper is devoted to the study of a long-term dynamic of anchovy population: reproductive parameters and its relation with water temperature for the purpose of potential prediction. The results of our own investigations made in 2000–2015 in the area bordering the south-western coast of Crimean peninsula (Sevastopol–Balaklava region) have been considered in the paper. The eggs were collected with Bogorov – Rass net (BR-80/113) from the layer of 0–10 m. Adult specimen were caught with pound seines. 702 ichthyoplankton samples and 941 mature anchovy females (gonad maturation stage V, VI–IV and VI–V) were analyzed. Calendar dates and duration of spawning season, intensity and efficiency of spawning, intraspecific composition of mature anchovy females were researched. Calendar dates of anchovy spawning beginning near the south-western coast of Crimea in 2000–2014 varied from the 2ⁿᵈ decade of May (early spawning) to the 3ʳᵈ decade of June (late spawning); finishing dates – from the 3ʳᵈ decade of August to the 3ʳᵈ decade of September. Total reproductive period duration was 8–14 weeks, average – 11 weeks. In long-term plan the time shift for earlier calendar dates was determined at the start of the spawning. Maximum peak of spawning intensity in 2012–2013 varied from 33.6 to 78.7 % (average 51.2 %). Peak of population spawning was in July – August, its repeatability in July – 25 and in August 66.7 %. The peak spawning shift to the earlier time was determined in perennial plan: in 2000–2005 years peak spawning periodicity amounts in August to 100 %; in 2007–2013 – only 50 %. Absolute number of eggs (spawning efficiency) change from 1.6 to 29.9 specimen·m-2 in 2000–2014 years (average 10.3 specimen·m-2). Low, average and high yielding years with number of eggs less than 10, 10–20 and more than 20.0 specimen·m-2 were determined. The average spawning efficiency was: 5.1, 14.5 and 25.0 specimen·m-2 respectively. Spawning efficiency in high-yielding years exceeded 1.7 and 4.9 times the efficiency of low and average-yielding years. In long-term plan the positive efficiency spawning trend was determined. In 2000–2001 the intraspecific structure reconstruction of anchovy took place, followed by redistribution of numerical relation in composition of spawning part of the Azov and the Black Sea subspecies in favor of the last one. In 2000–2004 relative abundance of Black Sea anchovy amounted 33.3 %, in 2005–2011 years – 76.7 %. Simultaneously a considerable catch growth was registered. Сorrelation coefficient of the Black Sea anchovy’s relative abundance and catch was 0.92. Calendar time of spawning beginning, its intensity and efficiency are closely connected with the water temperature. Lower temperature limit for mass spawning was 17.5 °С. The region of “maximum favorable spawning temperature” lays in the range of 23 °C and warmer. Nearly 2/3 of population reproductive potential is realized within this temperature range.

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Styan, C. A., e A. J. Butler. "Asynchronous patterns of reproduction for the sympatric scallops Chlamys bifrons and Chlamys asperrima (Bivalvia: Pectinidae) in South Australia". Marine and Freshwater Research 54, n.º 1 (2003): 77. http://dx.doi.org/10.1071/mf02019.

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Patterns of spawning activity were assessed by monitoring gonad states over 2.5 years for Chlamys asperrima and Chlamys bifrons at two sites in Gulf St Vincent, South Australia. Chlamys asperrima appeared to have a minor spawning in June, followed by a major spawning starting in late August. In contrast, the gonads of C. bifrons were regressed only during winter and it appeared that C. bifrons spawned for a long period, from late spring (September) until early autumn (March). At one site where sampling was frequent, there was evidence of three series of C. bifrons spawning events during the summer of 1994/95 and at least two series of events during 1995/96. Build-up and decrease in gonad weight was quick, but there was strong evidence of serial spawning for both species. Subsequently, we once observed C. asperrima spawning in situ at Edithburgh Jetty, at a time when gonad weights had been decreasing in previous years, but also long after the time when peak gonad weights had usually occurred. Only patches within the population were seen spawning, with scallops not spawning observed less than 100 m away from those that were. Indirect sampling of gonad condition also suggested that spawning in C. bifrons at Largs Bay was not always synchronous among patches of scallops within a population, nor always between sexes within patches.

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Finstad, Anders Gravbrøt, Leif Magnus Sættem e Sigurd Einum. "Historical abundance and spatial distributions of spawners determine juvenile habitat accessibility in salmon: implications for population dynamics and management targets". Canadian Journal of Fisheries and Aquatic Sciences 70, n.º 9 (setembro de 2013): 1339–45. http://dx.doi.org/10.1139/cjfas-2012-0455.

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Spatial distribution of spawning may have important ramifications for population dynamics in species where early life stages suffer from low mobility and high density-dependent mortality. Here, we use time series of spatial spawning distribution in Atlantic salmon (Salmo salar) to test for density-dependent behavioural effects on the spatial utilization of spawning sites and resulting juvenile habitat availability. The probability of utilizing spawning sites in a given year increased both with increasing spawner abundance and proximity to sites used the previous year. The accessible area for juveniles increased asymptotically with both current and time-lagged spawner abundance. Several nonexclusive mechanisms may be responsible for the observed direct and lagged density dependence of spawner distributions, including social aggregation, asymmetric competition for space, local homing, and habitat modification by the previous year’s spawners. Time-lagged density-dependent spawner distributions can be predicted to reduce the realized population growth rate. If such effects are not accounted for, this may lead to a downward bias in estimates of spawning targets or other associated conservation or management measures derived from population abundance time series.

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Aiken, D. E., e S. L. Waddy. "The Uncertain Influence of Spring Photoperiod on Spawning in the American Lobster, Homarus americanus". Canadian Journal of Fisheries and Aquatic Sciences 42, n.º 1 (1 de janeiro de 1985): 194–97. http://dx.doi.org/10.1139/f85-025.

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The literature contains a report that induction of final vitellogenesis and time of spawning in American lobsters (Homarus americanus) is controlled by spring photoperiod. However, we could not corroborate this. Two experiments with American lobsters held throughout the winter in Canadian Atlantic seawater temperatures indicated no effect of spring photoperiod on time of spawning. In one experiment the onset of spring photophase was delayed by 2 mo. In the second experiment the photophase at the winter solstice (9 h 46 min) was gradually shortened over ensuing months to 5 h 30 min on 7 July. Neither of these treatments altered the time of spawning relative to control animals on a simulated natural photoperiod cycle. Spawning occurred at photoperiods of LD 6:18 and LD 15:9.

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Jamieson, I. G., e P. W. Colgan. "Sneak spawning and egg stealing by male threespine sticklebacks". Canadian Journal of Zoology 70, n.º 5 (1 de maio de 1992): 963–67. http://dx.doi.org/10.1139/z92-137.

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Nest-raiding behavior by breeding male threespine sticklebacks was examined in a laboratory study to determine the contexts in which spawnings and egg stealing occur, and the effect, if any, of egg stealing on the mating success of the egg stealer. Of three males competing for mates at any one time, those that were last to complete construction of their nest and, subsequently, last to spawn in their own nest, raided most frequently. It was found that raids are initiated primarily during spawning by neighboring males and the majority of incidents of egg stealing are preceded by sneak spawnings. In many cases males steal eggs that they themselves potentially fertilized. However, the stolen eggs do not increase the chances of a male attracting a female to his nest to spawn. Stealing eggs may affect mating success in an open population, but under the conditions of the present experiment the adaptive significance of egg stealing remains unclear.

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