Vital rates of pelagic fish larvae (VITAL)

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Publications

Effect of temperature on the daily increment deposition in the Otoliths of European sardine Sardina pilchardus (Walbaum, 1792) Larvae

Publication . Soares, Claudia; Ferreira, Susana; Ré, Pedro; Teodosio, Maria Alexandra; Santos, António Miguel; Batista, Hugo; Baylina, Nuria; Garrido, Susana

Otolith microstructure analysis is a valuable tool to evaluate the relationship between larval age and growth and how it relates to environmental variability. Otolith growth and daily increment deposition were analyzed in sardine (Sardina pilchardus) larvae reared in the laboratory under different temperatures (13, 15, and 17 ◦C), with a diet rich in microalgae, rotifers, and copepods Acartia grani. The number and width of growth increments, first-check and otolith diameter were determined in the otoliths and then related to larval age and total length. At hatching, the sagittal otoliths consisted of a lenticular core with a diameter of 10.56 µm (±1.07 µm SD). Somatic growth increased with the increasing temperature and the growth rate of larvae reared at 13 and 15 ◦C was significantly lower than for larvae reared at 17 ◦C. At 17 ◦C, otoliths exhibited a higher diameter with wider increments than at 13 ◦C. There was a high variability of increment counts-at-age for larvae reared within the same temperature treatment. The increase of growth increments with larval size was higher for larvae reared at 17 ◦C until 35 days post-hatching than those growing at 15 ◦C. Scanning electronic microscopy confirmed that increments are deposited daily, with an average width smaller than 1 µm and as low as 0.33 µm, therefore impossible to distinguish using light microscopy. At colder temperatures, larval otoliths had thinner and less marked increments and lower growth rates, which can lead to incorrect age determinations. The effect of temperature on the otolith microstructure can help in identifying strong temperature gradients experienced by wild sardine larvae.

2021-11-08Journal article

Open access

Sardine validation temperatures - data supporting results published in "Effect of temperature on the daily increment deposition in the Otoliths of European Sardine Sardina Pilchardus (Walbaum, 1792) Larvae". Oceans

Publication . Soares, Claúdia; Ferreira, Susana; Ré, Pedro; Teodosio, Maria Alexandra; Santos, A. M. P.; Batista, Hugo; Baylina, Nuria; Garrido, Susana

Sardine Validation Temperatures - dataset supporting results published in Effect of Temperature on the Daily Increment Deposition in the Otoliths of European Sardine Sardina Pilchardus (Walbaum, 1792) Larvae. Oceans. Samples where collected at the Oceanário de Lisboa, in 2010 and analysed in the Instituto Português do Mar e da Atmosfera.

2021Dataset

Open access

Ecologia do recrutamento de pequenos pelágicos: capacidades natatórias e condição nutricional de larvas de sardinha (Sardina pilchardus,Walbaum 1792)

Publication . Silva, Luís Miguel Ribeiro da; Chícharo, Alexandra; Garrido, S.; Faria, Ana Margarida da Silva

As capacidades de natação das larvas de pequenos pelágicos e a sua influência na sobrevivência e dispersão estão pouco estudadas. Pela primeira vez, descreveram-se as capacidades natatórias de larvas de Sardina pilchardus (Walbaum 1792), em condições controladas em laboratório desde a eclosão até ao 75º dia pós-eclosão (dpe). Comparou-se a capacidade natatória (velocidade crítica de natação (Ucrit) e comportamento) e a condição nutricional (índice RNA/DNA) de larvas cultivadas com 4 diferentes regimes alimentares. À eclosão, as larvas concentraram-se à superfície e após o 2º dpe começaram a dispersar pela coluna de água. As larvas recém-eclodidas passaram a maior parte do tempo inativas, tendo o tempo dispendido a nadar aumentado com a idade, estabilizando ao 30º dpe, sendo dispendendido a totalidade do tempo a nadar. Ao 15º dpe as larvas começaram a resistir a correntes de 1,5 cm s-1 por períodos curtos de tempo. A Ucrit aumentou significativamente ao longo da ontogenia, atingindo um máximo de 9,47 cm s-1 numa larva com 19,1 mm de comprimento total e 55 dpe. Não foram detetadas diferenças significativas das capacidades natatórias entre larvas cultivadas nas diferentes dietas para as idades comuns a todas as dietas. O número de ataques a presas e sequências completas de predação (desde a fixação ao ataque) aumentaram com a idade; ao 25º dpe o número de ataques foi inferior a 2 ataques min-1 e ao 60º dpe observaram-se em média 4 (±0,8) ataques min-1. O crescimento larvar nas dietas de maior concentração (0,327 mm d-1.) e concentração intermédia (0,487 mm d-1) não teve diferenças siginificativas e foi significativamente superior às dietas de menor concentração e plâncton natural que foram semelhantes entre si. A condição larvar foi pouco variável durante a ontogenia, sem diferenças significativas entre as diferentes dietas. Da mesma forma, a relação entre as capacidades natatórias e a condição nutricional das larvas não foi significativa. As conclusões deste trabalho sugerem que numa fase inicial do desenvolvimento as larvas não são capazes de evitar a predação e controlar a dispersão, uma vez que têm reduzidas capacidades natatórias. No entanto, a partir do 45º dpe, as larvas são capazes de resistir às velocidades médias das correntes naturais, o que deverá ter consequencias importantes para a sua sobrevivência.

2013Master thesis

Open access

Assessing the impact of environmental forcing on the condition of anchovy larvae in the Cadiz Gulf using nucleic acid and fatty acid-derived indices

Publication . Teodosio, Maria; Garrido, Susana; Peters, J.; Miguel de Sousa Leitão, Francisco; Re, P.; Peliz, A.; Santos, A.M.P.

Understanding the environmental processes affecting fish larvae survival is critical for population dynamics,"conservation purposes and to ecosystem-based fishery management. Using anchovies (Engraulis encrasicolus) of the Cadiz Gulf as a study case and considering the "Ocean Triad" hypothesis, we investigate the larval ecophysiological status and potential survival in relation to oceanographic variables. Therefore, this study aims to describe the nutritional condition of anchovy larvae during spawning season (peak in summer) through nucleic acid- and fatty acid (FA)-derived indices and to analyze the effects of the major environmental parameters (Depth, Temperature, Salinity, Plankton biomass) on anchovy survival potential at early phases. Fish larvae were collected in August from 30 m to 400 m depth at 35 stations off the southern Iberian coast. A previous upwelling event influenced the oceanographic conditions of the more western stations off Cape Sao Vicente (CSV). Along the coast, the water became warmer from west to the east through Cape Santa Maria (CSM) ending at Guadiana estuary, where easterly winds originated the development of a counter current. The standardized RNA/ DNA (sRD) of anchovy larvae decreased throughout larval ontogeny, reflecting a reduction of growth during the development. Essential FA concentrations also decreased, but docosahexaenoic acid (DHA) in particular was highly conserved even after the reduction of total FA concentration in anchovy larvae related to the onset of swimming abilities (post-flexion phase). The oceanographic conditions (west upwelling, east counter current, and stratification) led to a nearshore aggregation of plankton and anchovy larvae with good ecophysiological conditions in the central area of the southern coast, where an optimal range of temperature and chlorophyll, as an indirect food proxy for anchovy larval development, were registered. The study proves that the oceanographic conditions of the study area are putative drivers of the ecophysiological condition of anchovy larvae to guarantee potential survival, supporting the "Ocean Triad" hypothesis with major repercussions for recruitment and population dynamics.

2017-02Journal article

Restricted access

Reproduction and respiration of a climate change indicator species: effect of temperature and variable food in the copepod Centropages chierchiae

Publication . Cruz, Joana; Garrido, Susana; Pimentel, Marta S.; Rosa, Rui; Santos, A. Miguel P.; Re, Pedro

The abundance of the calanoid copepod Centropages chierchiae has increased at the northern limits of its distribution in recent decades, mainly due to oceanic climate forcing, suggesting this as a key species in monitoring climate change. Laboratory experiments were conducted to study the combined effect of temperature, food type and concentration on the egg production rate (EPR) and hatching success (HS) of C. chierchiae. Females were fed on two monoalgal diets (Gymnodinium sp. and Phaeodactylum tricornutum) at two food concentrations and at three different temperatures (13, 19, 24C). Respiration rates of both genders were measured at four different temperatures (8, 13, 19, 24C). EPR was significantly different between temperatures and food concentrations, the maximum EPR being attained when the copepods were exposed to high food levels and at 19C. Prey type significantly influenced EPR; feeding on P. tricornutum resulted in higher egg production than Gymnodinium sp. HS was significantly lower at 13C than at 19 and 24C and higher with Gymnodinium sp. Respiration rates were sex independent and increased exponentially with temperature. To maintain basal metabolism, the minimum food intake of P. tricornutum ranged between 0.4 and 1.8 g C and for Gymnodinium sp. between 0.03 and 0.13 g C. Food intake was always higher than the metabolic demands, except for the highest temperature tested (24C). The present results confirm the sensitivity of C. chierchiae to temperature variations and may help in understanding the successful expansion of its distribution towards northern latitudes.

2013-10Journal article

Open access