* ICLARM is now known as WorldFish Center

Naga - The *ICLARM Quarterly
Vol. 23, No. 1 (January - March 2000)

Fishbyte (Fisheries Section of NTAFP)

Length-Weight Relationship of Marine Fishes from Southern Brazil
M. Haimovici and G. Velasco

The relationship between length (L) and weight (W) was estimated for 80 species belonging to 50 families of marine fishes from the shelf and upper slope of southern Brazil (lat. 28°S - 34°S). Sample sizes (n) for different species ranged from 11 to 14 741 specimens collected from commercial landings and research surveys. The fit of the equations (W=aLb) with a and b parameters estimated from regular and functional regression (of log-transformed weight and length data) as well as from a non-linear iterative process using the quasi-Newton algorithm were compared. The non-linear method gave the most accurate estimates in terms of residual sum of squares. Differences were less than 2.3% for n>500 compared with predictive regressions and 1.5% compared with functional regressions. No difference was observed between both predictive and functional regressions. Determination coefficients (r2) increased with sample size, and the highest r2 were obtained for 50<n<500, decreasing slightly for larger samples due to seasonal changes in the condition of the fishes.

M. Haimovici ( and G. Velasco ( are from Depto. Oceanografia, FURG. CX.P. 474, Rio Grande RS, Brazil, 96201-900.

Adaptive Response of Peruvian Hake to Overfishing
C. Wosnitza-Mendo and R. Guevara-Carrasco

Compensatory mechanisms of the Peruvian hake population (Merluccius gayi peruanus) in response to heavy exploitation and changes in species interaction are discussed. Changes in the rate of cannibalism, diet composition, maximization of fecundity and behavioral adaptation are noted.

C. Wosnitza-Mendo is from Pargue Bartolome Herrera 190, Lima 32 - Peru while R. Guevara-Carrasco is from the Instituto del Mar del Peru (IMARPE), Apartado 22, Callao, Peru. 

The Marine Fisheries of Jamaica
K. Aiken and G.A. Kong

The marine fisheries of Jamaica are almost entirely artisanal, with at least 15 000 fishers and an annual catch of approximately 7 000 t. A recent development is a small industrial fishery for queen conch and spiny lobster that earns significant foreign exchange for the country. The major aquatic resources are coral reef  fishes, conch, lobster, small pelagics and seasonal large pelagics. The major fishing grounds are the southern island shelf and Pedro Bank, a large oceanic bank 150 km to the southwest of Kingston. The fisheries are rated as overfished, except the queen conch fishery which is relatively well managed. A new Fisheries Bill is currently being reviewed with the intention of improving the efficiency of management measures and of fisheries administration. There are plans for rehabilitating the fisheries and developing them with a focus on their sustainability in the future.

K Aiken is a lecturer in the Department of Life Sciences, University of the West Indies, Mona campus. G. Andre Kong is the Director of Fisheries, Fisheries Division, Ministry of Agriculture, Kingston, Jamaica.

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