| 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
Abstract
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 (docmhm@super.furg.br)
and G. Velasco (pgobgvc@super.furg.br)
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
Abstract
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
Abstract
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.
 |
