Age estimation in common sole Solea solea larvae: validation of daily increments and evaluation of a pattern recognition technique

Close similarities have been found between the otoliths of sea-caught and laboratory-reared larvae of the common sole Solea solea (L.), given appropriate temperatures and nourishment of the latter. But from hatching to mouth formation. and during metamorphosis, sole otoliths have proven difficult to read because the increments may be less regular and low contrast. In this study, the growth increments in otoliths of larvae reared at 12 degrees C were counted by light microscopy to test the hypothesis of daily deposition, with some results verified using scanning electron microscopy (SEM), and by image analysis in order to compare the reliability of the 2 methods in age estimation. Age was first estimated (in days posthatch) from light micrographs of whole mounted otoliths. Counts were initiated from the increment formed at the time of month opening (Day 4). The average incremental deposition rate was consistent with the daily hypothesis. However, the light-micrograph readings tended to underestimate the mean ages of the larvae. Errors were probably associated with the low-contrast increments: those deposited after the mouth formation during the transition to first feeding, and those deposited from the onset of eye migration (about 20 d posthatch) during metamorphosis. SEM failed to resolve these low-contrast areas accurately because of poor etching. A method using image analysis was applied to a subsample of micrograph-counted otoliths. The image analysis was supported by an algorithm of pattern recognition (Growth Demodulation Algorithm, GDA). On each otolith, the GDA method integrated the growth pattern of these larval otoliths to averaged data from different radial profiles, in order to demodulate the exponential trend of the signal before spectral analysis (Fast Fourier Transformation, FFT). This second method both allowed more precise designation of increments, particularly for low-contrast areas, and more accurate readings but increased error in mean age estimation. The variability is probably due to a still rough perception of otolith increments by the GDA method, counting being achieved through a theoretical exponential pattern and mean estimates being given by FFT. Although this error variability was greater than expected, the method provides for improvement in both speed and accuracy in otolith readings.

Larval rearing of sea bass (Dicentrarchus labrax (L.) with a high survival

An experiment of larval rearing of sea bass is described. Larval density ranged from 50/l at the beginning of the experiment, to 1,4 fingerling/l after 3 months. Fingerlings were fed at that time with a pelletized artificial diet. Average weight was 0,8 g. Survival from the newly hatched larvae was 38%.

Processo biotecnológico voltado a produção de estoques poliploides do camarão-branco litopenaeus vannamei (decapoda, penaeidae)

without practical results so far. Protocols used in biotechnological cultured aquatic organisms aimed at increasing growth rates and disease resistance, have been studied and perfected. Among the available techniques, the application of chromosomal manipulation, although still nascent, is presented as a tool aimed at mitigating ecological and economical issues in shrimp farming. The polyploidization artificial method already employed in fish and shellfish, has been widely researched for use in farmed shrimp. Some limitations of this method of expansion in shrimp refer to a better knowledge of cytogenetic aspects, the level of sexual dimorphism and performance in growing conditions. To contribute on some of these issues, the present study aimed to characterize cytogenetic species Litopenaeus vannamei (Decapoda) and Artemia franciscana (Anostraca), analyze the effectiveness of methods for detection of ploidy, through the use of flow cytometry in processes of induction polyploidy cold thermal shock at different stages of development of newly fertilized eggs. Additionally, aimed also the qualitative and quantitative comparison of larval development between diploid and polyploid organisms, besides the identification of sexual dimorphism in L. vannamei, through geometric morphometrics. The results provide information relevant to the improvement and widespread use of biotechnological methods applied toward national productivity in shrimp farming

Kinetic Analysis of Gill (Na+,K+)-ATPase Activity in Selected Ontogenetic Stages of the Amazon River Shrimp, (Decapoda, Palaemonidae): Interactions at ATP- and Cation-Binding Sites

We investigated modulation by ATP, Mg2+, Na+, K+ and NH4 (+) and inhibition by ouabain of (Na+,K+)-ATPase activity in microsomal homogenates of whole zoeae I and decapodid III (formerly zoea IX) and whole-body and gill homogenates of juvenile and adult Amazon River shrimps, . (Na+,K+)-ATPase-specific activity was increased twofold in decapodid III compared to zoea I, juveniles and adults, suggesting an important role in this ontogenetic stage. The apparent affinity for ATP ( (M) = 0.09 +/- A 0.01 mmol L-1) of the decapodid III (Na+,K+)-ATPase, about twofold greater than the other stages, further highlights this relevance. Modulation of (Na+,K+)-ATPase activity by K+ also revealed a threefold greater affinity for K+ ( (0.5) = 0.91 +/- A 0.04 mmol L-1) in decapodid III than in other stages; NH4 (+) had no modulatory effect. The affinity for Na+ ( (0.5) = 13.2 +/- A 0.6 mmol L-1) of zoea I (Na+,K+)-ATPase was fourfold less than other stages. Modulation by Na+, Mg2+ and NH4 (+) obeyed cooperative kinetics, while K+ modulation exhibited Michaelis-Menten behavior. Rates of maximal Mg2+ stimulation of ouabain-insensitive ATPase activity differed in each ontogenetic stage, suggesting that Mg2+-stimulated ATPases other than (Na+,K+)-ATPase are present. Ouabain inhibition suggests that, among the various ATPase activities present in the different stages, Na+-ATPase may be involved in the ontogeny of osmoregulation in larval The NH4 (+)-stimulated, ouabain-insensitive ATPase activity seen in zoea I and decapodid III may reflect a stage-specific means of ammonia excretion since functional gills are absent in the early larval stages.

The Predation of Artemia Nauplii by the Larvae of the Amazon River Prawn, Macrobrachium amazonicum (Heller, 1862), is Affected by Prey Density, Time of Day, and Ontogenetic Development

The present study analyzed the effects of prey density, the time of day, and ontogenetic development on the predation of Artemia nauplii by the larvae of the Amazon river prawn, Macrobrachium amazonicum, as well as possible synergy among these factors. Larvae were raised in 120-L tanks with biological filter systems, and fed on recently hatched Artemia nauplii, using two feeding management protocols: (a) fed once per day at 2000 h (high density HD) and (b) half of the ration provided at 2000 h, complemented at 0800 h the following day by a replacement of the nauplii consumed up to a maximum of the full ration (low density with replacement LDWR). Each treatment consisted of six replicates. The consumption of nauplii was estimated prior to the feeding times. Consumption varied according to time of day, ontogenetic development, and feeding protocol. The larvae ingested more nauplii during the daytime at most developmental stages. Ingestion rates were similar during the day under both treatments, but at night the higher density of prey in the HD treatment caused a higher encounter rate and increased ingestion of nauplii by the larvae. Among the performance indicators only survival was greater in HD in comparison with LDWR; productivity and dry weight were similar. The results indicate a circadian trophic rhythm in M. amazonicum, with the encounter rate being an important mechanism for the capture of prey during the night. A second mechanism probably the visual system aids the perception of prey during the daytime. Based on these results, we suggest that feeding captive Amazon river prawn larvae only once a day would be appropriate and economically beneficial. Further work is necessary to determine the most effective time that this single feed should be applied.

Efeito da privação alimentar sobre alguns componentes bioquímicos (proteína, ADN e ARN) e o comportamento alimentar em larvas de pregado (Scophthalmus maximus,L.) em condições de cultivo

Dissertação de mest. em Estudos Marinhos e Costeiros, especialização em Aquacultura, Unidade de Ciências e Tecnologias dos Recursos Aquáticos, Univ. do Algarve, 1994

Connectivity patterns inferred from the genetic structure of white seabream (Diplodus sargus L.)

Themarine environment seems, at first sight, to be a homogeneousmediumlacking barriers to species dispersal. Nevertheless, populations of marine species show varying levels of gene flow and population differentiation, so barriers to gene flow can often be detected. Weaimto elucidate the role of oceanographical factors ingenerating connectivity among populations shaping the phylogeographical patterns in the marine realm, which is not only a topic of considerable interest for understanding the evolution ofmarine biodiversity but also formanagement and conservation of marine life. For this proposal,we investigate the genetic structure and connectivity between continental and insular populations ofwhite seabreamin North East Atlantic (NEA) and Mediterranean Sea (MS) aswell as the influence of historical and contemporary factors in this scenario using mitochondrial (cytochrome b) and nuclear (a set of 9 microsatellite) molecular markers. Azores population appeared genetically differentiated in a single cluster using Structure analysis. This result was corroborated by Principal Component Analysis (PCA) and Monmonier algorithm which suggested a boundary to gene flow, isolating this locality. Azorean population also shows the highest significant values of FST and genetic distances for both molecular markers (microsatellites and mtDNA). We suggest that the breakdown of effective genetic exchange between Azores and the others' samples could be explained simultaneously by hydrographic (deep water) and hydrodynamic (isolating current regimes) factors acting as barriers to the free dispersal of white seabream(adults and larvae) and by historical factors which could be favoured for the survival of Azorean white seabream population at the last glaciation. Mediterranean islands show similar genetic diversity to the neighbouring continental samples and nonsignificant genetic differences. Proximity to continental coasts and the current system could promote an optimal larval dispersion among Mediterranean islands (Mallorca and Castellamare) and coasts with high gene flow.

Infestation rates of the pedunculated barnacle Octolasmis lowei (Cirripedia: Poecilasmatidae) on the spider crab Libinia spinosa (Decapoda: Majoidea)

The prevalence and infestation intensities of Octolasmis lowei in the bronchial chambers of Libinia spinosa were evaluated according to the host's sex, size, and moult condition. Epibionts were classified as cyprid larvae, non-ovigerous or ovigerous according to their developmental stage. A median intensity of infestation of 21 epibionts/host was found (range = 1-644; Q(3) = 81). Epibiont prevalence values (88%) were higher on ovigerous female hosts than on males (55%) or on non-ovigerous females (31%). Intensity of infestation was positively correlated with host size in both sexes for non-ovigerous and ovigerous epibionts. No preference between host sex by cyprid larvae was observed, nor any correlation between cyprid abundance and host size. Cyprid larvae abundance was positively correlated with settled epibionts on both host sexes. The duration of the intermoult phase was the main factor linked to the establishment of sessile epibionts. These observations are important in relation to crabs that have a terminal moult, because these animals cannot eliminate their epibionts in future moults, thus increasing the importance of density-dependent mechanisms on epibiont establishment; in that way, prevalence of infestation alone can underestimate the real impact of infestation on the host's life cycle.

Two's a crowd: phenotypic adjustments and prophylaxis in anticarsia gemmatalis larvae are triggered by the presence of conspecifics.

2013

Water quality and zooplankton in tanks with larvae of Brycon Orbignyanus (Valenciennes, 1949)

Devido à importância das condições das variáveis da água e do alimento disponível no desenvolvimento e sobrevivência das larvas de peixes, o objetivo deste estudo foi avaliar o efeito do uso de dois tratamentos alimentares (ração + zooplâncton e somente zooplâncton) e a qualidade da água, em tanques de larvicultura de Brycon orbignyanus. A transparência total da água (45 cm) esteve associada principalmente ao curto tempo de residência, fluxo contínuo e baixa profundidade. As concentrações de oxigênio dissolvido variaram de 1,32 a 7,00 mg.L-1 no tratamento contendo ração + zooplâncton, e de 1,82 a 7,60 mg.L-1 no tratamento contendo somente zooplâncton. Os nutrientes foram diretamente influenciados pela adição de ração no meio com exceção do nitrito. Rotifera apresentou a maior densidade, variando ao longo do período experimental de 8,7 x 10(5) a 1,3 x 10(6) org.m-3 entre os quatro tanques estudados, num total de dez espécies. A menor densidade foi observada para Cladocera, variando de 4,7 x 10(4) a 2,1 x 10(5) org.m-3 num total de seis espécies encontradas, sendo Diaphanosoma birgei a única espécie classificada como muito freqüente. O uso de ração junto com zooplâncton proporcionou melhor rendimento para larvas de B. orbignyanus.

European lobster (Homarus gammarus) larvae under an acidification scenario: addressing biochemical, development and behaviour responses

A acidificação dos oceanos constitui uma problemática global e a realidade de que está, efetivamente, a acontecer não é uma consideração subjetiva. A Acidificação dos oceanos provocada por emissões de dióxido de carbono de origem antropogénica tem vindo a reduzir o pH das águas superficiais do Oceano e projeções preveem a continuidade deste processo. Embora muita investigação tenha sido desenvolvida no âmbito dos invertebrados que calcificam, tais como moluscos e crustáceos, poucos consideraram o estudo de efeitos ao nível sub-celular para avaliar stress oxidativo ou respostas funcionais do metabolismo energético em tais condições, interligando vários níveis de organização biológica. O objetivo do presente estudo foi o de avaliar os efeitos da exposição a diferentes níveis-alvo de pCO2 (controlo: 370 μatm; aumentado: 710 μatm) e de pH (controlo: 8.15; reduzido: 7.85) em parâmetros de crescimento bem como avaliar respostas comportamentais e bioquímicas relacionadas com stress oxidativo e metabolismo energético durante o desenvolvimento larvar de um crustáceo decápode. Este cenário de acidificação está de acordo com os RCPs previstos pelo Painel Intergovernamental para as Alterações Climáticas (IPCC, 2014) para o ano 2100. Para o presente estudo, foi utilizado o crustáceo Homarus gammarus (L.) – sendo uma espécie com elevado valor comercial, que tem vindo a sofrer elevada pressão de pesca em águas Europeias. Fêmeas adultas provenientes da costa Atlântica Oeste Portuguesa foram obtidas de um retalhista local. Após a eclosão em ambiente laboratorial controlado, larvas provenientes da mesma progenitora foram expostas às condições acima descritas desde o momento da eclosão até à chegada ao Estádio III. A sobrevivência individual e ocorrência de ecdise foram avaliados individualmente de 12h em 12h. Réplicas de cada tratamento foram recolhidas em momentos específicos durante o Estádio I (primeiro estádio larvar) e Estádio III (último estádio larvar) para análise morfométrica e de crescimento (peso fresco e comprimento carapaça) e respostas bioquímicas. Os biomarcadores analisados incluíram parâmetros relacionados com stress oxidativo e danos (atividade da enzima superóxido dismutase (SOD), peroxidação lipídica (LPO) e danos no DNA) e metabolismo energético (atividade da cadeia transportadora de eletrões (ETS) e da enzima lactato desidrogenase (LDH) e quantificação de Hidratos de Carbono). Os resultados obtidos sugerem que a sobrevivência diminui e que o período inter-muda é afetado durante a exposição a cenários de acidificação. No que respeita aos parâmetros de crescimento/morfométricos, larvas do cenário de acidificação apresentam uma tendência para crescimento diminuído, menor peso e comprimento de carapaça. As análises bioquímicas realizadas indicam a ocorrência de stress oxidativo sob condições de acidificação. Respostas ao nível do metabolismo energético não variaram significativamente entre tratamentos. Os resultados apontam também para que fases larvares possam possuir um sistema antioxidante ainda em desenvolvimento, tornando-as mais suscetíveis ao stress oxidativo. As fases larvares são uma fase vulnerável e crucial no ciclo de vida das espécies, influenciando o recrutamento e a renovação de stocks. Este estudo contribui para um melhor entendimento sobre a vulnerabilidade desta espécie num cenário de alterações climáticas – Acidificação dos oceanos – ao endereçar os mecanismos envolvidos nas respostas deste crustáceo a este agente causador de stress.

Cross-shore transport in a daily varying upwelling regime: A case study of barnacle larvae on the southwestern Iberian coast.

With favored offshore and downstream advection, the question of which physical mechanism may promote onshore transport of larvae in upwelling systems is of central interest. We have conducted a semi-realistic high resolution (0.25 km) numerical study of Lagrangian transports across the inner-shelf under upwelling-favorable wind forcing conditions, focusing on the shelf area of the Southwestern Portuguese coast, in the lee of Cape Sines. We add our findings to several years of biological observations of C. montagui, a planktonic species with higher recruitment during the upwelling peak timely with the daylight flood. Simulations cover a fifteen days period during the summer of 2006. We focused on Spring and Neap tide periods and observed upfront differences between simulations and the in situ observa- tions. However, the model is capable of representing the main dynamics of the region, namely the re- petitive character of the inner-shelf currents. We find that the cross-shore flow varies significantly in the daily cycle, and locally within a scale of a few kilometers in association with local topography and the presence of the cape. We consider the region immediately in the lee of the cape to be an upwelling shadow where the larvae became retained, and found that tidally tied migration proves beneficial for successful recruitment during the spring tides period. Our work suggested that the wind is not the only mechanism responsible for the daily variability of the cross-shore exchange. However, its sharp reversal at midday is critical for the advection of larvae towards the coast.

Histopathology from liver of tuvira (Gymnotus spp.) parasitized by larvae of nematodes.

Abstract: The aim of this study was to evaluate the histological changes in the liver of thirty-five Gymnotus spp. parasitized by endohelminths collected between April 2012 to October 2013 in commercial bait fish farming of Pantanal basin. Histological cuts of 7?m were stained with hematoxylin-eosin for parasites research and liver changes and have also been submitted to the Perls histochemical method for evaluation of hemosiderosis (Fe+++) based on the incidence degree and severity of change (Grade I, II and III) and tests for the presence of central melanomacrophages. Parasites identified were: Brevimulticaecum sp. with a prevalence of 22,9%, Eustrongylides sp 17,1%, Contracaecum type I 68,7%, Contracaecum type II 5,7%, Contracaecum type III 5,7% and larvae of Anisakidae 11,4%. Histological analysis showed intense disorganization of hepatic parenchyma with degenerate hepatocytes due to high parasitic infection, changes that can be deleterious and compromise the organism functioning, being harmful to the health of evaluated animals. Also evidencing normal tissue interleaved with different stages of Fe+++ deposit in grades II and III, injuring or destroing the cell. Histopathological changes in the tuvira?s liver suggested a chronic response and the development of a balance relation between tuvira and parasitism by endohelminth identified in this study. There are also a testimony to the health condition of commercial bait fish farming on current ecosystem conditions.

Occurrence Of Isoflavonoids In Brazilian Common Bean Germplasm (phaseolus Vulgaris L.).

Common bean (Phaseolus vulgaris) is present in the daily diet of various countries and, as for other legumes, has been investigated for its nutraceutical potential. Thus, 16 genotypes from different gene pools, representing seven types of seed coats and different responses to pathogens and pests, were selected to verify their isoflavone contents. The isoflavonoids daidzein and genistein and the flavonols kaempferol, myricetin, and quercetin were found. Grains of the black type showed the highest concentrations of isoflavonoids and were the only ones to exhibit daidzein. IAC Formoso, with high protein content and source of resistance to anthracnose, showed the greatest concentration of genistein, representing around 11% of the content present in soybean, as well as high levels of kaempferol. Arc 1, Raz 55, and IAC Una genotypes showed high content of coumestrol. The results suggest the use of IAC Formoso to increase the nutraceutical characteristics in common bean.

Influence Of The Stage Of Ripeness On The Composition Of Iridoids And Phenolic Compounds In Genipap (genipa Americana L.).

Genipap fruits, native to the Amazon region, were classified in relation to their stage of ripeness according to firmness and peel color. The influence of the part of the genipap fruit and ripeness stage on the iridoid and phenolic compound profiles was evaluated by HPLC-DAD-MS(n), and a total of 17 compounds were identified. Geniposide was the major compound in both parts of the unripe genipap fruits, representing >70% of the total iridoids, whereas 5-caffeoylquinic acid was the major phenolic compound. In ripe fruits, genipin gentiobioside was the major compound in the endocarp (38%) and no phenolic compounds were detected. During ripening, the total iridoid content decreased by >90%, which could explain the absence of blue pigment formation in the ripe fruits after their injury. This is the first time that the phenolic compound composition and iridoid contents of genipap fruits have been reported in the literature.