Macromedusae of Southern Brazil: temporal variation, population structure and biochemical composition

O objetivo do presente estudo foi realizar um levantamento das espécies de macromedusas ocorrentes no Litoral Norte de Santa Catarina, avaliar sua dinâmica populacional e as variações na composição bioquímica, por meio de saídas de campo mensais, ocorridas entre janeiro de 2012 até outubro de 2014. As análises bioquímicas das umbrelas incluiram seu conteúdo em água, carboidratos, proteínas, lipídeos, cinzas, e, destas, sua composição. Foram encontradas seis espécies de macromedusas: Chiropsalmus quadrumanus e Tamoya haplonema (Cubozoa); Olindias sambaquiensis e Rhacostoma atlanticum (Hydrozoa); Chrysaora lactea e Lychnorhiza lucerna (Scyphozoa). As espécies de maior ocorrência e típicas da região foram Olindias sambaquiensis e Rhacostoma atlanticum. Ambas apresentaram alta variabilidade entre os anos, sendo que as maiores densidades foram obtidas entre o outono e o inverno de 2014, associadas a um inverno menos rigoroso e águas mais salgadas. As Cubozoas apresentam maior conteúdo em matéria orgânica, sendo as cinzas ricas em metais. R. atlanticum apresentou sazonalidade na composição química, estando as proteínas relacionadas com o pico reprodutivo da espécie.The objectives of this study were to record the macromedusae species on the north coast of Santa Catarina, and to estimate their population dynamics and variations in their biochemical composition, based on the specimens obtained in the by-catch of artisanal shrimp fishing between January 2012 and October 2014. Cohort analysis was performed to evaluate the population dynamic of the most frequent species. Biochemical analyses of the umbrellas were conducted on their water, carbohydrate, protein, lipid, ash and metals contents. Six species of macromedusae were found: Chiropsalmus quadrumanus and Tamoya haplonema (Cubozoa); Olindias sambaquiensis and Rhacostoma atlanticum (Hydrozoa), and Chrysaora lactea and Lychnorhiza lucerna (Scyphozoa). The species with the highest occurrence, and typical of the region, were Olindias sambaquiensis and Rhacostoma atlanticum. These species showed high inter-year variability, the highest densities being observed between autumn and winter 2014, associated with a less severe winter and coastal water with higher salinity. The distribution of size classes of O. sambaquiensis suggests two well-defined cohorts in spring/summer and in autumn/winter. R. atlanticum showed continuous reproduction and inter-year variation but a high value for protein content related to the reproductive peak in autumn. However, the Cubozoa species showed higher organic matter and metal content than the other classes

Macromedusae of Southern Brazil: temporal variation, population structure and biochemical composition

Abstract The objectives of this study were to record the macromedusae species on the north coast of Santa Catarina, and to estimate their population dynamics and variations in their biochemical composition, based on the specimens obtained in the by-catch of artisanal shrimp fishing between January 2012 and October 2014. Cohort analysis was performed to evaluate the population dynamic of the most frequent species. Biochemical analyses of the umbrellas were conducted on their water, carbohydrate, protein, lipid, ash and metals contents. Six species of macromedusae were found: Chiropsalmus quadrumanus and Tamoya haplonema (Cubozoa); Olindias sambaquiensis and Rhacostoma atlanticum (Hydrozoa), and Chrysaora lactea and Lychnorhiza lucerna (Scyphozoa). The species with the highest occurrence, and typical of the region, were Olindias sambaquiensis and Rhacostoma atlanticum. These species showed high inter-year variability, the highest densities being observed between autumn and winter 2014, associated with a less severe winter and coastal water with higher salinity. The distribution of size classes of O. sambaquiensis suggests two well-defined cohorts in spring/summer and in autumn/winter. R. atlanticum showed continuous reproduction and inter-year variation but a high value for protein content related to the reproductive peak in autumn. However, the Cubozoa species showed higher organic matter and metal content than the other classes