Browsing by Author "Ré, Pedro"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Effect of temperature on the daily increment deposition in the Otoliths of European sardine Sardina pilchardus (Walbaum, 1792) LarvaePublication . Soares, Claudia; Ferreira, Susana; Ré, Pedro; Teodosio, Maria Alexandra; Santos, António Miguel; Batista, Hugo; Baylina, Nuria; Garrido, SusanaOtolith 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.
- Multi-marker DNA metabarcoding for precise species identification in ichthyoplankton samplesPublication . Ferreira, André O.; Barroso, Cristina; Mouteira Azevedo, Olga; Duarte, Sofia; Egas, Conceição; Fontes, João T.; Ré, Pedro; Santos, A. Miguel P.; Costa, Filipe O.Ichthyoplankton monitoring is crucial for stock assessments, offering insights into spawning grounds, stock size, seasons, recruitment, and changes in regional ichthyofauna. This study evaluates the efficiency of multi-marker DNA metabarcoding using mitochondrial cytochrome c oxidase subunit I (COI), 12S rRNA and 16S rRNA gene markers, in comparison to morphology-based methods for fish species identification in ichthyoplankton samples. Two transects with four coastal distance categories were sampled along the southern coast of Portugal, being each sample divided for molecular and morphological analyses. A total of 76 fish species were identified by both approaches, with DNA metabarcoding overperforming morphology-75 versus 11 species-level identifications. Linking species-level DNA identifications with higher taxonomic morphological identifications resolved several uncertainties associated with traditional methods. Multi-marker DNA metabarcoding improved fish species detection by 20-36% compared to using a single marker/amplicon, and identified 38 species in common, reinforcing the validity of our results. PERMANOVA analysis revealed significant differences in species communities based on the primer set employed, transect location, and distance from the coast. Our findings underscore the potential of DNA metabarcoding to assess ichthyoplankton diversity and suggest that its integration into routine surveys could enhance the accuracy and comprehensiveness of fish stock assessments.
- Plankton community and copepod production in a temperate coastal lagoon: what is changing in a short temporal scale?Publication . Cruz, Joana; Teodosio, Maria; Garrido, Susana; Ben-Hamadou, Radhouane; Chicharo, Luis; Ré, Pedro; Santos, A.M.P.Coastal lagoons are often exposed to intense short-term environmental changes and strong anthropogenic pressures influencing zooplanktonic communities and production. However, most works focus on long-term temporal scales using monthly or seasonal sampling strategies. The present study analysed the structure of the mesozooplanktonic assemblages, the production (egg production rates) and physiological condition (RNA:DNA ratio) of the copepod Acartia clausi in a temperate coastal lagoon (Ria Formosa) during the summer, using an intensive sampling approach. Salinity was the main factor affecting the short-term variability of mesozooplankton composition, followed by tidal phase (ebb tides) and semilunar cycle (spring tides). There was a positive relationship between the abundance of Appendicularia and the cladoceran Penilia avirostris with the toxic dinoflagellate Gymnodinium catenatum, suggesting no deleterious effects. The egg production rate of A. clausi was influenced by salinity and ammonia concentration, with a positive correlation between the egg productivity and the macronutrient, showing a possible adaptation of this calanoid species. The RNA:DNA index was positively related to egg production rate, suggesting that it is a good proxy for the reproductive output of copepods, even in short-term periods. This study shows that different timescales need to be included in regular monitoring of planktonic assemblages in coastal lagoons in order to understand the influence of environmental and anthropogenic variables on marine organisms.
- 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". OceansPublication . Soares, Claúdia; Ferreira, Susana; Ré, Pedro; Teodosio, Maria Alexandra; Santos, A. M. P.; Batista, Hugo; Baylina, Nuria; Garrido, SusanaSardine 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.