Environmental Change Enhances Cognitive Abilities in Fish

Cichlid fish subjected to a single change in food ration early in life show enhanced learning abilities during juvenile and adult stages

Trophic Structure and Community Stability in an Overfished Ecosystem

Since the collapse of the pelagic fisheries off southwest Africa in the late 1960s, jellyfish biomass has increased and the structure of the Benguelan fish community has shifted, making the bearded goby (Sufflogobius bibarbatus) the new predominant prey species. Despite increased predation pressure and a harsh environment, the gobies are thriving. Here we show that physiological adaptations and antipredator and foraging behaviors underpin the success of these fish. In particular, body-tissue isotope signatures reveal that gobies consume jellyfish and sulphidic diatomaceous mud, transferring “dead-end” resources back into the food chain

Growth parameters estimates of Maurolicus stehmanni Parin & Kobyliansky 1996 (Teleostei, Sternoptichydae) from south and southeastern Brazilian waters

This paper on the otolith microstructure analysis of Maurolicus stehmanni presents estimates of the species growth parameters and longevity. The species inhabits the outer shelf and slope of the southern and southeastern Brazilian Exclusive Economic Zone (EEZ). Growth parameters are important for the knowledge of the species' life history and rational management. M. stehmanni constitutes an important link between the initial and final components of the alimentary chain of the open sea ecosystem, being one of the main food items for squids and large pelagic fish. Among the various applied methods those which presented the most coherent values for growth parameters and were best adapted to the von Bertallanfy's equation were: Li= 55mm K= 0.0088/day and to= 5.5 days Maurolicus stehmanni's longevity is of less than one year (around 220 days) and the sagita daily otolith rings are useful for the determination of its age.<br>Este estudo, baseado na análise da microestrutura dos otólitos de Maurolicus stehmanni, apresenta estimativas dos parâmetros de crescimento e longevidade para esta espécie que habita a plataforma externa e o talude da ZEE sul-sudeste do Brasil. Estes parâmetros são importantes para o conhecimento da estratégia de vida da espécie e para o manejo deste recurso, que constitui um importante elo entre os componentes iniciais e finais da teia alimentar no ecossistema de mar aberto, sendo um dos principais itens na dieta das lulas e grandes peixes pelágicos. Dentre os vários métodos aplicados, os valores dos parâmetros de crescimento mais coerentes com a estratégia da espécie e que melhor se ajustaram à equação de von Bertallanfy foram: Li= 55mm K= 0.0088/dia e to= 5.5 dias. A espécie vive cerca de 220 dias e as marcas diárias nos otólitos sagita são apropriadas para a determinação da idade