Publisher : Bulletin of Marine Science
Place of publication :
Publication year : 2003
Thematic : Coral Reef
Language : English
Note
Using information on catch per unit effort, size, and age structure, a suite of quantitative
tools were employed to detect trends, and model the dynamics of the spiny lobster,
Panulirus argus, resource in Banco Chinchorro without assuming that equilibrium conditions
apply. A multiseasonal depletion model was fitted to monthly catch rate (CPUE)
data, with catch in numbers and effort measured as fishing trips, for five successive seasons
1988–1989 to 1992–1993. The depletion model captured seasonal and interannual
variations of catch rates and provided point estimates of recruitment per fishing season
from 43,870–241,150 individuals. The model considered two month-specific values of
the catchability coefficient q, whether or not a month showed peaks in catch rate. Monthly
fishing mortality rates F were also derived, and F-values per fishing season varied from
0.30–0.38 season-1. These estimates were consistent with those obtained for age-based
methods; conversely, they were quite different from those previously estimated by methods
assuming equilibrium conditions. Data on commercial size grades were available for
two pairs of consecutive fishing seasons, 1983–1984, 1984–1985 and 1989–1990, 1990–
1991. Mean recruitment length to the fishery has declined between 1983–1991. Agebased
methods with growth parameters for Cuban lobsters provided total (Z) and byfishing
(F) mortality rates, which also declined over the same period, assuming a constant
natural mortality rate (M) applies. Overall, this study suggests that fishing effort
and fishing mortality must be maintained at levels closer to those applied in the period
1988–1993. A current issue in population dynamics, namely, open versus closed populations,
and their consequences for management and for further research are discussed.
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Keywords : southern flounder
Encoded by : Pauline Carmel Joy Eje
