Júlio Neves de Araújo

Age and growth of coney (Cephalopholis fulva), from the central coast of Brazil

Coney (Cephalopholis fulva) otoliths were collected from 1997 to 1999 off the central coast of Brazil. Analysis of the edges of otoliths sections suggests that one translucent and one opaque zone are formed once a year. Coney age and size-ranges were 2-25 years and 172-428 mm total length (TL) respectively. The von Bertalanffy growth equation was TL t =316(1-e -0.138(t+5.301) ). The maximum age observed in this study is well above that previously reported for coney.

Evidence of seasonal changes in community structure for a coastal ecosystem in the central coast of Brazil, south-west Atlantic

This study reports on the seasonal variations of the community structure of a coastal ecosystem, off the central coast of Brazil. Samples were collected on a monthly basis on board a bottom otter trawl vessel from October 2003 to September 2004. A total of 57 species belonging to 26 families and 10 orders were collected. Resident species, which presented a high proportion of juveniles throughout the year, were the most abundant. Among these, benthonic fish of the Sciaenidae family were the dominant species, followed by Tetraodontiformes, nektonic Sciaenidae and Clupeiformes. Benthonic fish were more abundant during the spring/summer months (October to February) and pelagic species dominated the autumn/winter months (May to September). However, these differences were not statistically significant. The spring/summer months were also characterized by reproduction activity, while the autumn/winter months saw high proportions of juveniles. Indicator species analyses showed that 5 species presented significant differences in their occurrence and abundance throughout the seasons of the year. This study shows that the coastal area is an important place for reproduction and a nursing ground of many species. It also shows evidence of community-level reproductive patterns for a tropical ecosystem. Future studies are necessary to identify the likely ecosystem forcings underlying these patterns.

Age and growth of the queen triggerfish Balistes vetula (tetraodontiformes, balistidae) of the central coast of Brazil

Dorsal spines (n=649) of the queen triggerfish Balistes vetula were collected between 1997 to 1999 at the central coast of Brazil and used to evaluate fish growth. The marginal increment analysis validated that 1 increment was formed annually (n=476), with minimum values observed at the summer, and coinciding with the maximum proportion of translucent growth bands. Fishs maximum fork length and age were 460 mm and 14 years respectively. The parameters of the von Bertalanffy function were: Fl∞ = 441.3 mm, K = 0.14 and T0= -1.8. Weight gain by year ranged from about 110 g yr-1 for age 5 to about 30 g yr-1 for age 14. Compared to other studies, B. vetula growth in the Central coast of Brazil was slow, which could be related to the influence of the oligotrophic water from Brazil current. Our results indicate that B. vetulas fisheries in the Central coast of Brazil until 1999 have caught mostly adult individuals over the sexual maturation lenght, 60% of them with ages from 6 to 8 yr.

Idades e crescimento da cioba, Ocyururs chrysurus, da Costa Central do Brasil

A idade e o crescimento da cioba da costa central do Brasil foram estudados a partir de leituras de otolitos obtidos em amostragens mensais de desembarques comerciais, realizados nas cidades de Vitoria e Vila Velha, entre os anos de 1998 e 1999. Atraves da analise do incremento marginal, foi verificada a formacao anual de uma zona translucida a partir do final do outono e durante o inverno. Foram observadas ciobas de 2 a 19 anos. Os comprimentos furcais (CF) medios retrocalculados variaram de 108 mm para idade 1 a 524 mm para idade 19. A equacao de Von Bertalanffy ajustada aos CF medios retrocalculados foi CFt = 567,1 (1 - e -0.130 (t + 0.773)). A relacao comprimento peso foi P = 2,68x10-5CF2.914, onde P = peso total em gramas. O crescimento e lento, com os incrementos anuais em peso aumentando gradativamente ate atingir o maximo de 164 g entre as idades 7 e 8 anos. Os resultados deste trabalho indicam que a cioba tem longa expectativa de vida e baixas taxas de crescimento somatico, caracteristicas das especies mais sensiveis a exploracao pesqueira.

Effectiveness of lobster fisheries management in New Zealand and Nova Scotia from multi-species and ecosystem perspectives

&NA; In New Zealand and Nova Scotia, lobster (Jasus edwardsii and Homarus americanus, respectively) is the most valuable export fishery. Although stock assessments and indicators assist in evaluating lobster fisheries, ecosystem effects are largely unknown, hindering ecosystem‐based fisheries management (EBFM). We employed ecosystem models for the Cook Strait, New Zealand and western Scotian Shelf, Nova Scotia, Canada, to evaluate trade‐offs between catches and ecosystem impacts in lobster fisheries from single‐ and multi‐species perspectives. We ran simulations to independently determine exploitation rates that produced maximum sustainable yield (MSY) for lobster, and for all fished groups. We then ran simulations using these MSY exploitation rates simultaneously, and simulations to maximize multi‐species MSY (MMSY). Our results indicate that current lobster exploitation rates in both regions are greater than those producing MSY, and have significant ecosystem impacts. Simulating multi‐species fisheries, in both systems the sum of single‐species MSY for all fished groups was less than the sum of catches where exploitation rates were run simultaneously. Runs maximizing MMSY across the entire ecosystem increased exploitation rates on many fished groups, and produced even greater total catch—yet with much greater ecological costs—and in Nova Scotia, collapses of sharks, large predators, and lobster themselves. As fisheries management moves towards multi‐species and ecosystem‐based approaches, we suggest that MMSY targets should be treated similarly to MSY—not as a target, but a limit. Even then, careful evaluation is required before implementation to ensure that there are no undesirable economic or ecological consequences.