Academic literature on the topic 'Paralarvas'

Abstract Shea, E. K., and Vecchione, M. 2010. Ontogenic changes in diel vertical migration patterns compared with known allometric changes in three mesopelagic squid species suggest an expanded definition of a paralarva. – ICES Journal of Marine Science, 67: 1436–1443. Planktonic and newly hatched cephalopods are routinely called paralarvae. Currently, the onset of diel vertical migration (DVM) marks the end of the paralarval phase, although changes in ontogenic growth trajectories may also be used. Patterns of DVM are reported for the first time for three poorly understood mesopelagic squid species. Discrete-depth samples taken during the Amsterdam Mid North Atlantic Plankton Expeditions (AMNAPE) of 1980–1983 are used to examine the timing of ecological and morphological changes in Chtenopteryx sicula, Mastigoteuthis magna, and Brachioteuthis sp. 3. DVM patterns are species-specific, and ontogenic changes in DVM coincide with allometric changes in the arm, fin, and funnel characters of C. sicula at 7 mm mantle length. Mastigoteuthis magna is not concentrated in the upper 250 m of the water column during the day, and no clear DVM pattern is found in Brachioteuthis sp. 3, meaning that the endpoint of the paralarval phase cannot be defined ecologically in these species. Other ecological transformations, e.g. changes in prey-capture ability, are therefore explored as alternatives to DVM. The pad-shaped club and long neck are proposed as visual markers of the end of the paralarval phase of C. sicula and Brachioteuthis sp. 3, respectively.

Abstract González, Á. F., Otero, J., Pierce, G. J., and Guerra, Á. 2010. Age, growth, and mortality of Loligo vulgaris wild paralarvae: implications for understanding of the life cycle and longevity. – ICES Journal of Marine Science, 67: 1119–1127. Age, growth, and mortality were estimated for the first time in wild paralarvae of the common squid, Loligo vulgaris, by examining growth increments in the statoliths of 273 animals collected off the Ría de Vigo (NW Spain, NE Atlantic). Hatching was all year round for the period 2003–2005, with a peak during late spring and a secondary peak during early autumn. Paralarvae varied from 1260 to 7580 µm, and their abundance decreased abruptly as they grew. Statolith increments were clearly visible without grinding in almost all material, allowing reliable estimation of age. Paralarvae are planktonic for at least 3 months. Growth in dorsal mantle length (DML) during that period fitted an exponential equation. The instantaneous relative growth rates were 2.11, 2.15, and 1.82% DML d−1 for 2003, 2004, and 2005, respectively, and there were no significant differences in size-at-age between the 3 years. Taking into account the growth rates estimated for the whole cycle of L. vulgaris, we suggest that the lifespan may previously have been underestimated by 3 months, because the proximity of the rings deposited during paralarval and early juvenile stages would prevent accuracy in enumerating the number of growth increments in later stages. The estimated instantaneous rate of total mortality during the first 90 d of a paralarva life was 9.6, 5.3, and 4.8% d−1 for 2003, 2004, and 2005, respectively. Eye diameter was a reliable and rapid way of estimating DML and age.

Abstract Cephalopod paralarval species richness, abundance and size structure were surveyed wduring an anomalous warm period (2014–2017) in the Cabo Pulmo National Park (CPNP), Gulf of California, Mexico. Paralarval taxa from six families (Cranchiidae, Enoploteuthidae, Ommastrephidae, Onychoteuthidae, Argonautidae and Octopodidae) were identified. Most taxa were of tropical biogeographic affinity and oceanic habitats. Highest paralarval richness occurred during spring associated with the northward movement of Tropical Surface Water, while the lowest was recorded during autumn with the southward flow of the Gulf of California water mass. Although 89% of the paralarvae were collected at or close to their species hatching size, none of the paralarval taxa showed a consistent seasonal spawning period. A canonical correspondence analysis showed three taxonomic assemblages: Argonauta and Helicocranchia–Onychoteuthis groups correlated with northward currents and high zooplankton biovolumes (ZB) and SD complex–Abraliopsis group with southward currents and intermediate ZB. Our Helicocranchia pfefferi paralarvae are the first recorded for the Gulf of California. At least 11 cephalopod taxa reproduce in CPNP. This area represents a suitable spawning habitat for cephalopods of socio-economic value.

Abstract Martins, R. S., Roberts, M. J., Chang, N., Verley, P., Moloney, C. L., and Vidal, E. A. G. 2010. Effect of yolk utilization on the specific gravity of chokka squid (Loligo reynaudii) paralarvae: implications for dispersal on the Agulhas Bank, South Africa. – ICES Journal of Marine Science, 67: 1323–1335. Specific gravity is an important parameter in the dispersal of marine zooplankton, because the velocity of currents, and therefore the speed of transport, is usually greatest near the surface. For the South African chokka squid (Loligo reynaudii), recruitment is thought to be influenced by the successful transport of paralarvae from the spawning grounds to a food-rich feature known as the cold ridge some 100–200 km away. The role of paralarval specific gravity on such transport is investigated. Specific gravity ranged from 1.0373 to 1.0734 g cm−3 during the yolk-utilization phase, implying that paralarvae are always negatively buoyant, regardless of yolk content. The data were incorporated into a coupled individual-based model (IBM)—Regional Ocean Modelling System model. The output showed that dispersal was dominantly westward towards the cold ridge. Also, modelled paralarval vertical distribution suggested that hydrodynamic turbulence was an important factor in dispersal. The negative buoyancy of early chokka squid paralarvae may reduce the risk of paralarvae being advected off the eastern Agulhas Bank and into the open ocean, where food is less abundant, so specific gravity may be important in enhancing the survival and recruitment of chokka squid.

Aberrant statolith microstructure was observed in an immature female of the squid Todarodes sagittatus (Cephalopoda: Ommastrephidae) caught in the Moroccan shelf. The paralarval statolith, (a central part of adult statolith that developed at paralarval stage), showed the first 12 growth increments outside the nucleus was reversed to the posterior side of the adult statolith, and its main axis was turned perpendicularly to the main axis of the adult statolith. However, further statolith growth followed the common pattern, and the statolith acquired its normal shape at the level of 55–60 growth increments. Such aberrance in a direction of the paralarval statolith can be explained by its complete detachment from the macula statica princeps (MSP) during strong impact to the head of the paralarva (e.g. by a predator) and further occasional re-attachment of the statolith to the MSP again.

AbstractHorizontal and vertical distribution of cephalopod paralarvae (PL) from the Mesoamerican Barrier Reef System (MBRS) in the Western Caribbean was studied during two oceanographic cruises in 2006 and 2007. A total of 1034 PL belonging to 12 families, 22 genera, 24 species, 5 morphotypes and a species complex were identified. Abralia redfieldi, Onychoteuthis banksii and Ornithoteuthis antillarum were the most abundant taxa. The taxonomic identification from these three species was corroborated with DNA barcoding (99.8–100% of similarity). Paralarvae of Octopus insularis were reported for the first time in the wild. Most PL occupied the Caribbean Surface Water mass in the 0–25 m depth stratum. Largest paralarval abundances were related to local oceanographic features favouring retention such as the Honduras Gyre and Cozumel eddy. No day-night differences were found in PL abundance, although Abralia redfieldi showed evidence of diel vertical migration. Distribution of PL in epipelagic waters of the MBRS was probably related to ontogenetic migration, hydrographic features of meso and subscale, and to the circulation regimes dominated by the Yucatan Current. The MBRS represents an important dispersion area for PL, potentially connecting a species-rich Caribbean community with the Gulf of Mexico and Florida waters.

The common octopus, Octopus vulgaris, weighing 1.4 mg at hatching and reared in the laboratory (mean 21.2 °C), doubled their weight roughly every 8.5 days to a mean of 173.2 mg after 60 days when they became benthic. Changes in paralarval allometry during development were strongly marked in the case of arm length: suckers were added and the arms grew concomitantly from day 10 and growth rate accelerated from day 20. Neither cannibalism nor schooling behaviour occurred during the planktonic stage. Survival rate to settlement was 8.9%. The paralarvae of O. vulgaris exhibited presettlement reflexes from day 36 and settled between days 47 and 54, suggesting considerable potential for dispersal. Comparison of these results with previous studies suggests that paralarvae settle when they reach a critical size irrespective of age, and that the duration of the planktonic period is probably temperature dependent. After settlement, octopuses still bore Koelliker organs, lacked papillae on the body surface, were capable of feeding on inert prey, and exhibited negative phototaxis and reclusive behaviour like adults. The main period of settlement under natural conditions in the northwestern Mediterranean Sea is probably September–October.

Ommastrephid squids undergo remarkable morphological change during the transition from planktonic paralarvae to adults. These changes are characterized by changes in the relative growth of body dimensions and mark phases and stages in post-embryonic development. The following morphometric characters of paralarval and juvenille Illex argentinus ranging in size from 1–55 mm ML were measured: dorsal mantle length (ML), mantle width (MW), head width (HW), eye diameter (ED), right arm lengths (AIL) (AIIL) (AIIIL) (AIVL), proboscis length (PL), proboscis division (PD), fin length (FL), fin width (FW), right tentacle length (TL), club length (CIL), dactylus length (DL) and carpus + manus length (CML). The relative growth of AIL, AIIL, AIIIL, HW and ED, showed discontinuities at c. 14 mm ML, while AIL, AIIL, AIIIL, AIVL, FL, and TL showed other discontinuities at c. 28 mm ML. These discontinuities seem to be related to the activity and ability of the animal to obtain food and survive in different environments. At an early phase (1–14 mm ML), there is a rapid development of the arms, suckers and fins. In the second stage (14–28 mm ML) there is a rapid development of the tentacles and clubs. In the third (>28 mm ML), the juvenile grows more in length in relation to other body parts. No morphological change, besides the proboscis division, takes place at the end of rhynchoteuthion stage. This may indicate the necessity for re-evaluation of the paralarval phase in Ommastrephidae.

Se describe la composición de especies, distribución, abundancia y frecuencia de paralarvas de cefalópodos en el mar peruano. Se determinó un total de 14 familias, 8 géneros, 4 especies en un total de 1109 muestras de zooplancton colectadas con red Hensen a 50 metros de profundidad desde la superficie, proveniente de 8 cruceros de investigación ejecutados durante los años 2013 y 2014; siendo las especies más dominantes Argonauta spp. (41.4%) y Abraliopsis sp. (6.4%); y las familias Ommastrephidae (13%), Octopodidae (9.1%), Gonatidae (3.9%) y Pyroteuthidae (3.7%). Las paralarvas mostraron una distribución espacial y una relación especie-específica con las masas de agua. Las especies de Argonauta spp. estuvieron relacionadas con ASS, ACF y AES/ATS, y el aumento de sus abundancias relacionadas con el aumento de temperatura; la familia Ommastrephidae relacionadas con ASS y ACF, con una distribución oceánica; la familia Octopodidae distribuida solo en el norte-centro dentro de la plataforma continental; la familia Gonatidae asociadas únicamente a ACF; mientras que las familias Onychoteuthidae y Pyroteuthidae no mostraron patrón de distribución ni preferencia por alguna masa de agua específica. Species composition, distribution, abundance and frequency of paralarvae in Peruvian sea are described. It was determined a total of 14 families, 8 genera and 4 species were determined in a total of 1109 zooplankton samples collected with Hensen net to 50m deep from the surface from 8 vessel research carried out during 2013 and 2014; being the most dominant the species Argonauta spp. (41.4%) y Abraliopsis sp. (6.4%); and families Ommastrephidae (13%), Octopodidae (9.1%), Gonatidae (3.9%) and Pyroteuthidae (3.7%). Paralarvae showed a spatial distribution and species-specific relationship with water masses. The species Argonauta spp. was related with SSW, CCS and ESW/TSW, and increased their abundances related to the temperature rise; la family Ommastrephidae related with SSW and CCW, with an oceanic distribution; the family Octopodidae distributed only in the north-center within the continental shelf; the family Gonatidae associated only with CCW; while the families Onychoteuthidae and Pyroteuthidae didn´t show distribution pattern or preference for any specific water masses.

Orientador : Drª. Erica Alves Gonzales Vidal
Coorientador : Dr. José Guilherme Bersano Filho
Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Terra, Programa de Pós-Graduação em Sistemas Costeiros e Oceânicos. Defesa: Pontal do Paraná, 27/03/2015
Inclui referências : f. 33-39
Resumo: Uma das maiores limitações para o desenvolvimento do cultivo do polvo comum (Octopus vulgaris) é a falta de uma dieta que possa ser empregada em larga escala e que reduza as altas taxas de mortalidade registradas durante a larvicultura. Devido à elevada taxa metabólica, as paralarvas de polvo requerem alimento vivo de qualidade nutricional ideal. Dietas baseadas unicamente em náuplios de artêmia não foram adequadas para promover o crescimento das paralarvas. O oferecimento de presas naturais, como os copépodes, em combinação com náuplios de artêmia parece ser uma alternativa viável e que merece ser avaliada. Os objetivos deste trabalho foram obter as taxas de primeira alimentação em paralarvas de Octopus vulgaris de diferentes idades quando submetidas a diferentes dietas, possibilitando comparações entre as idades, entre dietas e entre idades e dietas. Também foram comparados os valores das taxas de alimentação obtidos neste estudo com os estimados através do modelo proposto por O'Dor & Wells (1987). A obtenção das taxas de primeira alimentação envolveu o cultivo simultâneo de três grupos de paralarvas de O. vulgaris submetidas a diferentes dietas em um período de 24 horas: (1) copépodes; (2) náuplios de artêmias; (3) mista (50% copépodes + 50% náuplios de artêmias), em uma densidade de 60 presas L-1. Esse delineamento foi repetido para 3 idades diferentes (2; 3 e 5 dias). Os resultados mostraram que os valores médios das taxas de primeira alimentação oscilaram entre 2,7 e 3,7 presas.h-1 para as diferentes idades e dietas e foram mais elevadas durante as primeiras seis horas para todas as dietas. Houve diferenças significativas (p<0,05 ANOVA) entre os tempos, mas não houve interação deste com nenhum dos outros dois fatores; houve pouca diferença entre as idades. Já a diferença entre as dietas não foi significativa a nível de p<0,05, mas a nível de p<0,1 (0,089). A redução progressiva das taxas de ingestão pode estar associada à diminuição da densidade de presas (ind.L-1) ao longo das 24h de experimento, à saciedade das paralarvas e ao fato de que, como predadores visuais, reduzem suas taxas de alimentação durante a noite. As taxas de alimentação, de crescimento e taxa metabólica observadas no presente trabalho, tanto para náuplios de artêmias como para copépodes, não permitiram uma comparação concreta com os valores observados pelo modelo, pois nenhum dos valores se aproximaram ao que seria ideal para o cultivo das paralarvas de O. vulgais. Os valores estimados pelo modelo indicam que o consumo de copépodes aporta duas vezes mais calorias para as paralarvas do que náuplios de artêmias. É possível concluir que retardar a primeira alimentação reduz o tempo de contato entre paralarvas e presas, exercendo efeitos deletérios, tanto para o sucesso de captura, quanto para as taxas de sobrevivência. Palavras-chave: alimentação; copépode; dieta; náuplio de artêmia; Octopus vulgaris; paralarva.
Abstract: One of the main limitations to the development of common octopus (Octopus vulgaris) mass culture is the lack of adequate diets that provide low mortality rates in large-scale larvicultures. Previous trials using diets based exclusively on artemia nauplii were not able to promote significant octopus paralarvae growth since they require live food of higher nutritional quality. The supply of natural prey such as copepods, in combination with artemia nauplii seems to be a viable alternative and deserves more attention. The objective of this work was to obtain information about the first feeding rates of Octopus vulgaris paralarvae of different ages when submitted to different diets, allowing comparisons among ages, among diets and among ages and diets. The feeding rates values obtained in this study were also compared with those estimated using the model proposed by O'Dor & Wells (1987). Obtaining the first feeding rates involved the simultaneous cultivation of three groups of O. vulgaris paralarvae submitted to different diets in a 24-hour period: (1) copepods; (2) artemia nauplii; (3) mixed (50% copepods + 50% artemia nauplii), in a density of 60 prey L-1. This experimental design was repeated for 3 different ages (2, 3 and 5 days). The results showed that mean values of first feeding rates ranged from 2.7 to 3.7 prey.h-1 for different ages and diets and, were highest, during the first six hours for all diets. There were significant differences (p <0.05 ANOVA) between the times, but there was no interaction of this with any of the other two factors; There was little difference between the ages. However, the difference between the diets was not significant at p <0.05, but at p <0.1 (0.089). The progressive reduction of ingestion rates may be associated to three different factors: 1. a decrease in prey density (ind.L-1) over the 24-hour experiment. 2. The satiety of the parallels. 3. As visual predators, they would reduce their feeding rates during at night. The feeding, growth and metabolic rates observed in the present study, for both artemia and copepods, did not allow a concrete comparison with the values observed by the model, since none of the values approached what would be ideal for the cultivation of O. vulgaris paralarvae. The values estimated by the model indicate that the consumption of copepods provides twice as many calories to the paralarvae when compared to artemia based diet. It is possible to conclude that delaying the first feeding reduces the contact time between paralarvae and prey, exerting deleterious effects, both for success of capture and for survival rates. Key-words: artemia nauplii; copepod; diet; Octopus vulgaris; paralarvae.

Lulas da família Loliginidae são recursos pesqueiros em crescente importância no ecossistema marinho da Plataforma Continental Sudeste (PCSE) do Brasil. No entanto, informações sobre a distribuição dos estágios iniciais do seu ciclo de vida são bastante escassas. Com base em amostras de plâncton coletadas por 11 cruzeiros oceanográficos pretéritos do Instituto Oceanográfico da USP entre 1991 e 2005, o presente estudo teve como objetivo a identificação da ocorrência de paralarvas de Loliginidae na região entre o Cabo de São Tomé (RJ) e Cananéia (SP). Das 644 amostras analisadas, foram encontradas 246 paralarvas, sendo 121 identificadas em nível de espécie (Doryteuthis sanpaulensis n=75, Doryteuthis plei n=39, Lolliguncula brevis n=6 e Pickfordiateuthis pulchella, n=1). Os padrões de distribuição da Família em relação aos processos oceanográficos foram identificados a partir de mapas de distribuição horizontal e vertical de abundância, temperatura e salinidade. Modelos Lineares Generalizados (GLMs) foram utilizados para detectar os fatores que explicariam a ocorrência e a abundância de Loliginidae, os quais indicaram que a profundidade e a temperatura superficial do mar são as principais variáveis explanatórias. Uma Análise de Redundância (RDA) evidenciou os principais padrões de distribuição observados das três principais espécies de Loliginidae em relação às variáveis oceanográficas. D. sanpaulensis predominou na região norte da área de estudo, associada a águas frias e a eventos de ressurgência. D. plei ocorreu principalmente na região sul da área e em águas mais quentes. L. brevis foi encontrada apenas na região estuarina de Santos, em águas rasas e menos salinas. Os resultados obtidos representam uma contribuição relevante ao conhecimento sobre a Oceanografia Pesqueira das lulas no ecossistema marinho regional.
Loliginid squids are fisheries resources of increasing importance in the shelf ecosystem of Southeastern Brazil. Therefore, information about distribution of the early stages of their life cycle is scarce. Based on plankton samples collected by eleven historical oceanographic surveys cruises of the University of São Paulo\'s Oceanographic Institute between 1991 and 2005, the present study aimed identification of the occurrence of Loliginidae paralarvae in the region between Cabo de São Tomé (22ºS) and Cananéia (25ºS). From 664 samples analyzed, 246 paralarvae were found, being 121 identified to the species level, (Doryteuthis sanpaulensis n=75, Doryteuthis plei n=39,, Lolliguncula brevis n=6 and Pickfordiateuthis pulchella, n=1). The distributional patterns of Loliginidae in relation to oceanographic processes were identified by using horizontal and vertical maps of abundance, temperature and salinity. Generalized Linear Models (GLMs) were used to detect the factors that explain Loliginidae occurrence and abundance, which indicated that depth and sea surface temperature, were major explanatory variables. A Redundancy Analyses (RDA) showed the main observed distribution patterns of the three species of Loliginidae in relation to oceanographic variables. D. sanpaulensis occurred in the northern region associated to cold waters and upwelling events. D. plei occurred mainly in the southern region of the study area and in warmer waters.L. brevis was found in the estuarine region of Santos, in shallow and low salinity waters. The obtained results represent a relevant contribution to squids Fisheries Oceanography in the regional marine ecosystem.

BORGES, D. A. Octopus insularis: descrição de desova e paralarvas recém-eclodidas, cultivo de sub-adultos em diferentes sistemas e aspectos da fisiologia digestória de animais selvagens e cultivados. 2013. 119 f. Tese (doutorado) - Universidade Federal do Ceará, Instituto de Ciências do Mar, Programa de Pós-Graduação em Ciências Marinhas Tropicais, Fortaleza-CE, 2013.
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From cephalops, octopuses are considered economically interesting species for aquaculture. Their fishery has been steadily decreasing since 1990’s, which has led to increase in the demand for octopuses. In 2006 researchers have found in the Brazilian northeast coast a kind of octopus initially identified as Octopus vulgaris, and later, in 2008, identified as Octopus insularis. In chapter 01 of this thesis was describe newly-hatched paralarvae of Octopus insularis and defined its first life habit as planktonic with a positive phototaxis and no lecitotrófica phase. It has been determined that the time between the onset of spawning and hatching is approximately 25 days. It was found that the O. insularis lay their eggs in clusters with an average density of 390eggs/cm and no egg size variance was observed due to variation in female’s size. For chapter 02 was developed a laboratory system with closed recirculating water for food preference and grow out experiments with O. insularis sub-adults. For the first test, the double choice food, acrylics “Y” were used. The foods tested were crab (Callinectes bocourti) gastropod (Stramonita brasiliensis) and sardines (Sardinella spp), all tested paired. We observed the capture of all foods, however there was a clear preference of crab and fish across the gastropod. Even observing a higher crab frequency capture, no significant difference was observed between the frequency of catching crab and fish. Later we tested the grow out of O. insularis sub-adults at 23 and 28°C using crab as food. For all ongrowing indices used, grow out at 28°C show higher values than at 23°C. A total weight gain (ΔW) of 309.8g, a relative weight gain (GR) of 100.9%, an absolute growth rate (AGR) of 9.4g/day and a specific growth rate (SGR) of 2.1%BW/day were registered for 28°C test. Even with a higher food intake by the 28°C cultured group, there was no difference between the feed conversion rate (FCA) between groups cultured at 23 and 28°C. It was also accomplished the O. insularis sub-adults grow out in floating cages being offered different proportions of crabs and fish as food. It was observed a higher growth by the animals feed exclusively by crabs, and this test shown an AGR of 13.6g/day, and a SGR of 1.4%BW/day. There were no significant difference in the growth rates of the groups fed only fish and fed 50% fish and 50% crab. In chapter 03 were analyzed some of the digestive enzymes of the digestive tract of wild and cultured O. insularis species. For the total alkaline protease activity was observed greater activity in the posterior salivary gland (GSP) in wild individuals. For total acidic proteolytic activity no significant difference between the wild and cultured group was observed. Significant activity was only observed in the digestive gland (GD). Trypsin activity was observed in GD and GSP for both groups, wild and cultured, although cultured xi group have shown much lower activity them wild group. For chymotrypsin activity, activities were observed in the intestine (INTEST) and GSP for both analyzed groups, however wild group presented higher values of enzyme activity. Analyzing the aminopeptidases activity for 9 different amino acids, it was found a greater activity, for most of analyzed amino acids, in wild group than cultured group. There is also a strong relationship between these aminopeptidases that occur in the wild group GSP and muscle composition of animals from this same group. For amylase activity, was observed a high activity in various organ of the digestive tract, specifically the anterior salivary gland (GSA), GSP, cecum (CEC), GD and INTEST, and again wild group shown a higher activity than culture group.
Dentre os cefalópodes os polvos são considerados espécies de grande interesse econômico para a aquicultura. Sua pesca vem decrescendo gradualmente desde os anos 1990, o que levou a um aumento na demanda por polvos. Em 2006 pesquisadores encontraram na costa do nordeste do Brasil uma espécie de polvo inicialmente identificada como o Octopus vulgaris, e posteriormente, em 2008, identificado como Octopus insularis. No capitulo 01 desse trabalho foi realizado a descrição de paralarvas recém-eclodidas de O. insularis sendo definido seu hábito de vida inicial como planctônico com fototaxia positiva e ausência de fase lecitotrófica. Foi determinado que o tempo entre o início da desova e a eclosão dos ovos é de aproximadamente 25 dias. Identificou-se que o O. insularis põem seus ovos em cachos com uma densidade média de 390 ovos/cm de cacho e não foi verificado variação do tamanho dos ovos em virtude da variação do tamanho das fêmeas. Para o capítulo 02 foi desenvolvido toda uma estrutura laboratorial com sistema fechado de recirculação de água para a realização dos testes de predileção de alimento bem como para os testes de engorda do O. insularis. Inicialmente foi realizado o teste de dupla escolha de alimento com sub-adultos de O. insularis utilizando “Y” de acrílico. Os alimentos testados foram siri (Callinectes bocourti) gastrópode (Stramonita brasiliensis) e sardinha (Sardinella spp), sendo todos testados dois a dois. Observou-se a captura de todos os alimentos, contudo houve uma clara predileção do siri e do peixe frente ao gastrópode. Mesmo observando-se uma maior frequência de captura dos animais pelo alimento siri, não foi verificado uma diferença significativa entre a frequência de captura do siri e do peixe. Posteriormente realizou-se o cultivo de sub-adultos do O. insularis a 23 e 28°C sendo utilizado siri como alimento. Para todos os índices de crescimento utilizados, o cultivo a 28°C foi superior ao a 23°C sendo observado para 28°C um ganho de peso total (ΔW) de 309,8g, um ganho de peso relativo (GR) de 100,9%, uma taxa de crescimento absoluta (AGR) de 9,4g/dia e uma taxa de crescimento específica (SGR) de 2,1%BW/dia. Mesmo havendo uma maior ingestão de alimento pelo grupo cultivado a 28°C não se observou diferença significativa entre o fator de conversão alimentar (FCA) entre os grupos cultivados a 23 e 28°C. Foi realizado também o cultivo de sub-adultos do O. insularis em gaiolas flutuantes sendo ofertado diferentes proporções de siri e peixe na alimentação dos indivíduos. Observou-se um maior crescimento dos animais alimentados apenas com siri sendo obtidos valores de AGR de 13,6g/dia e SGR de 1,4%BW/dia. Não foi observada diferença significativa para os índices de crescimento dos grupos alimentados apenas com ix peixe e alimentados com 50% de peixe e 50% de siri. Durante o capítulo 03 foram analisadas algumas das enzimas digestivas do trato digestório de animais selvagens e cultivados da espécie O. insularis. Para a atividade proteolítica alcalina total observou-se uma maior atividade na glândula salivar posterior (GSP) em indivíduos selvagens. Para a atividade proteolítica total ácida não foi observada diferença significativa entre o grupo selvagem e cultivado, sendo observada atividade significativa apenas na glândula digestiva (GD). A atividade de tripsina foi observada na GD e GSP dos dois grupos tenso o grupo cultivado apresentado valores bem mais baixos de atividade que o grupo selvagem. Para a atividade de quimotripsina foram observadas atividades na GSP e intestino (INTEST) dos dois grupos analisados tendo o grupo selvagem apresentado maiores valores de atividade enzimática. Ao analisar a atividade de aminopeptidases referente a 9 diferentes aminoácidos verificou-se que para a maioria desses aminoácidos houve uma maior atividade do grupo selvagem frente ao grupo cultivado. Verificou-se também uma forte relação dessas aminopeptidades que ocorrem na GSP de animais do grupo selvagem com a composição do musculo desses animais. Quanto a atividade de amilase foi observado uma elevada atividade em vários órgão do trato digestório, marcadamente a glândula salivar anterior (GSA), GSP, ceco (CEC), GD e INTEST, sendo novamente presenciada uma maior atividade por parte do grupo selvagem.

Flying squids develop all its life cycle in the water column, as planktonic paralarvae and then as nektonic subadults and adults. In this Ph. D. Thesis, light was shed over several poorly understood aspects of the ontogeny and phylogeny of the Family Ommastrephidae. The mechanism of sperm migration from spermatangia to the female seminal receptacles was studied. Spermatozoa are able to actively migrate between both structures. The morphology of the hatchling of three Mediterranean ommastrephid species was studied based on embryos obtained by in vitro fertilization and a dichotomous key was develop to identify NE Atlantic species. The first feeding diet of paralarvae was assessed through laser-capture microdissection and DNA metabarcoding. The results indicate an ontogenetic shift from detritivorism to active predation. Molecular data indicate that the taxonomic name Ommastrephes bartramii actually hides four biological species. These advances in scientific knowledge have potential applications for a better understanding of the ecology, physiology, biodiversity and fishery science that will foster a deeper understanding of flying squids.
Las potas desarrollan todo su ciclo vital en la columna de agua, como paralarvas planctónicas y luego como subadultos y adultos nectónicos. En esta Tesis Doctoral, se ha arrojado luz sobre algunos aspectos poco estudiados de la ontogenia y la filogenia de Familia Ommastrephidae. Se estudió el mecanismo de migración espermática desde los espermatangios hasta los receptáculos seminales de la hembra. Los espermatozoides son capaces de migrar activamente entre ambas estructuras. Se estudió la morfología de los recién nacidos de tres especies mediterráneas de pota basándose en embriones generados por fecundación in vitro y se desarrolló una clave dicotómica para identificar las especies del Atlántico NE. Se estudió la primera alimentación de las paralarvas mediante una combinación de microdisección láser y DNA metabarcoding: los resultados indican una fase detritívora seguida de un cambio ontogenético hacia la depredación activa. Nuestros datos moleculares muestran que bajo el nombre taxonómico Ommastrephes bartramii en realidad se esconden cuatro especies biológicas. Estos avances en el conocimiento científico tienen aplicaciones potenciales para una mejor comprensión de la ecología, fisiología, biodiversidad y ciencia pesquera de las potas

The fishery for octopus in Northwest Mexico has increased to over 2,000 tons annually, but to date the specific composition of the catch has been ignored. With at least three main species targeted by artisanal fisheries in the region with distinct life histories, the lack of basic biological information about the distribution, metapopulation size and structure of each species could impede effective fisheries management to avoid overexploitation. We tested if different life histories of three species of octopus could help predict observed patterns of genetic diversity, population dynamics, structure and connectivity and how this information could be relevant to the sustainable management of the fishery. We sequenced two mitochondrial genes and genotyped seven nuclear microsatellite loci to identify the distribution of each species in 20 locations from the Gulf of California and the west coast of the Baja California peninsula. We tested five hypotheses derived from population genetic theory based on differences in the fecundity and dispersal potential for each species. We discovered that Octopus bimaculoides with low fecundity and direct development (without a planktonic phase) had lower average effective population size and genetic diversity, but higher levels of kinship, population structure, and richness of private alleles, than the other two species. These features indicated limited dispersal and high local recruitment. In contrast, O. bimaculatus and O. hubbsorum with higher fecundity and planktonic phase as paralarvae had higher effective population size and genetic diversity, and overall lower kinship and population structure than O. bimaculoides. These observations supported higher levels of gene flow over a larger geographical scale. O. bimaculatus with the longest planktonic paralarval duration and therefore larger dispersal potential had differences in the calculated parameters possibly associated with increased connectivity. We propose O. bimaculoides is more susceptible to over exploitation of small, isolated populations and could have longer recovery times than the other two species. This species may benefit from distinct fishery management within each local population. O. bimaculatus and O. hubbsorum may benefit from fishery management that takes into account metapopulation structure over larger geographic scales and the directionality and magnitude of larval dispersal driven by ocean currents and population connectivity among individuals of each locality. The distribution of each species and variations in their reproductive phenology is also important to consider when establishing marine reserves or seasonal fishing closures.

Includes abstract.
Includes bibliographical references (leaves 115-126).
This thesis focuses on these raised concerns and attempts to refine the modelling approach used to test the WTH. This is achieved by investigating squid paralarval survival and their specific gravity using aquarium experiments together with an improved ocean model and IBM. The influence of temperature on yolk utilization was assessed through experimentation. Tank experiments found that yolk utilization rates in chokka squid paralarvae are directly affected by temperature with faster rates at high temperature and slower rates at low temperature.

Resumo: Estudos sobre o desenvolvimento morfológico do bico nos estágios iniciais do ciclo de vida de um cefalópode podem aumentar o conhecimento sobre a ecologia de paralarvas, mas são raros na literatura. No presente trabalho foram examinados bicos de 18, 16 e 31 paralarvas de Chiroteuthis cf. veranyi (3,62 a 13,62 mm comprimento do manto (CM)), Liocranchia reinhardti (2,80 a 20,63 mm CM) e Doryteuthis opalescens (2,25 a 12,30 mm CM), respectivamente. As estruturas das mandíbulas superior (MS) e inferior (MI) foram medidas e os valores foram comparados ao CM por regressão linear múltipla, de forma a determinar as influências relativas de cada uma no crescimento. Cada estrutura foi comparada entre espécies através de ANOVA para detectar possíveis diferenças. As mandíbulas apresentaram diferentes níveis de desenvolvimento e mudanças marcadas puderam ser observadas em CM distintos. Coloração foi observada principalmente em L. reinhardti e em D. opalescens. As paredes laterais e capuz (MS) e asas e paredes laterais (MI) foram as estruturas mais robustas, com uma importância significativa também do rostro (MI) para L. reinhardti. Dentes (MI) e uma fenda no rostro, características de cefalópodes ancestrais, foram observados em todas as espécies. Essas estruturas desapareceram total e parcialmente (fenda persistente) nos maiores indivíduos de L. reinhardti e D. opalescens, respectivamente, e foram retidas em todos os indivíduos analisados de C. cf. veranyi. Os resultados deste estudo revelam informações importantes sobre a morfologia funcional do bico durante os primeiros estágios do ciclo de vida de um cefalópode.

At the moment, the biggest bottleneck in Octopus vulgaris culture is the paralarvae stage, which is characterized by high mortalities and poor growth. This thesis pretended to study the effect of three different preys (Palaemon elegans, Grapsus grapsus and Artemia spp. enriched with Tetraselmis chuii) on the survival and growth of 0. vulgaris paralarvae. It also targets the nutritional composition of newly hatched paralarvae and the effect of the diets after nine days of culture. Prey biological characteristics and level of predation were also covered during this study. Regarding growth, survival and the biochemical composition of paralarvae, two experiments were conducted. In the 1” experiment, paralarvae were reared at density of 5 paralarvae/L and Artemia spp. juveniles (1-ART) and P. elegans zoea (1-PAL) were tested. In the 2“d experiment, the paralarvae rearing density was reduced to 1.5 paralarvae/L to raise the number of preys per paralarvae and Artemia spp. juveniles (2- ART), P. elegans zoea (2-PAL) and G. grapsus zoea (2-GRA) were tested. Low survival rates were obtain during the 1” experiment and although higher rates were obtain during the 2“d experiment, no statistical differences (P>0.05) between experiments and treatments were found due to the high variability recorded. Nonetheless, higher growth rates (P<0.05) were found in treatments with low paralarvae density (2“d experiment) and fed with decapod crustacean zoeae (2-PAL - IGR=5.18i 0.96% and 2-GRA - IGR=6.29 Í 1.10). The biochemical composition of octopus hatchlings in the present study was similar to that reported in previous works. After nine days of rearing it was observed a nutritional change in paralarvae composition. Regardless from prey provided, a reduction in DHA and PUFA content and DHA/EPA ratio was detected (P<0.05). Nevertheless, the best rearing success was obtained in the 2-PAL and 2-GRA groups, which were the ones with the higher DHA/EPA ratio (P<0.05). Although no differences were found between the 2-ART group and octopus hatchlings (P>0.05), the remaining treatments displayed a raise in ARA content that might be related with food input. The artemia juveniles (prey with the poorer results in terms of paralarvae rearing) were the most different prey contrasting with the FA profile of octopus paralarvae, suggesting the importance of this factor in the octopus development. On the other hand, crab zoeae, which presented good rearing results, also presented low content in protein, phospholipids and to some extent cholesterol; which were higher in artemia juveniles (P<0.05). The prawn zoea was the most attacked and captured prey during the predation trial and, although not different from artemia juveniles due to the high variability (P>0.05), both decapod crustacean zoeae were highly ingested by the octopus paralarvae. The low number of attacks and captures on crab zoeae observed and the high number of ingestions recorded could have been related to the fact that, when placed in the tank, most of the zoeae sank rapidly to the bottom, not being quickly detected. From the present results it seems that not just the biochemical composition of prey influences the octopus; paralarvae development, but also the number of preys ingested may suggest as a limiting factor. A reduction in the water column depth of the rearing tanks could reduce the energy spent in prey capture from the bottom, improving energy efficiency and promoting paralarvae growth. Considering the results obtained with Artemia spp. despite being the most available and easiest prey to culture, it does not seem to be an adequate prey for octopus paralarvae. On the other hand, decapod crustacean zoea seems a promising model if zoeae availability is improved.
Neste momento a indústria da aquacultura apresenta um enorme potencial de expansão e desenvolvimento, apesar de alguma saturação dos mercados com espécies chave. Um desses exemplos é a saturação do mercado mediterrânico com dourada e robalo. Devido à necessidade de diversificar essa oferta de mercado e pelo elevado valor comercial dos cefalópodes, o cultivo do polvo comum (Octopus vulgaris) foi ganhando um maior interesse nestes últimos anos. Actualmente o cultivo de polvo tem-se cingido à captura de juvenis selvagens com um peso minimo de 750 g (peso mínimo legal de captura) e a sua engorda até 2-3 kg durante 3 a 4 meses em tanques de terra ou em jaulas onshore. O presente estudo foi realizado com o intuito de analisar o efeito de três presas [juvenis de Artemia spp. cultivados durante 7 a 10 dias com Tetraselmis chuii, larvas pós-eclodidas de Grapsus grapsus (caranguejo) e larvas de Palaemon elegans (camarão)] na taxa de sobrevivência, crescimento e composição nutricional, de paralarvas de O. vulgaris. Foi também realizado um estudo de predação e de algumas características biológicas das presas, como tamanho da larva e fecundidade destas espécies. Para o estudo dos efeitos das presas nas paralarvas de polvo, foram realizadas duas experiencias. Na primeira experiência foi usada uma densidade de 5 paralarvas/L para avaliar o efeito dos juvenis de Artemia spp. (1-ART) e das zoea de camarão (1- PAL). Na segunda experiência, de modo a que o número de presas por paralarva fosse superior, a densidade de cultivo das paralarvas foi reduzida para 1.5 paralarvas/L. Nesta última experiência foi analisado o efeito das três presas, 2-ART, 2-PAL e 2-GRA, que correspondem aos grupos de paralarvas alimentadas com artemias juvenis, larvas de camarão e larvas de caranguejo respectivamente. O cultivo das paralarvas foi realizado em tanques cilindro-cónicos de fibra de vidro de 100L com paredes pretas e fundo branco. Foi usado um sistema aberto com água salgada proveniente de mar aberto e aplicado um foto-periodo de 12L:12E (L - luminosidade; E - escuridão) com uma intensidade de 200 lux na superficie da água.