Annual growth and maturity function of the squat lobster Pleuroncodes monodon in central Chile
1993; Inter-Research; Volume: 97; Linguagem: Inglês
10.3354/meps097157
ISSN1616-1599
Autores Tópico(s)Marine and fisheries research
ResumoLength-frequency data (LFD) for the squat lobster Pleuroncodes rnonodon (Decapoda, Galatheidae) from 5 research surveys carried out in central Chlle (35"20'S to 36'20's) between 1982 and 1991 were analysed to model male and female growth.The 1991 data were further used to model female maturity.From the 5 yr of LFD, 17 year classes were identified in males and 19 in females.To classlfy those year classes into age classes, a simple statistical procedure based on a stochastic dependency of growth on age was developed.The procedure classified male and female year classes into 6 and 7 age classes, respectively.Size variances due to within-year-class (indvidual) variability and among-year-classes (temporal) variability were estimated.The ratio between temporal and individual size variance did not increase with age.This indicates that size variation of individuals reaching a given age is mainly determined by the inherent variability of their year class rather than by environmental changes encountered across ages.A von Bertalanffy growth function provided a good description of both male and female growth.There were significant differences in the parameterization of the growth function between males and females: females were smaller than males for every age class.Logistic regression on female maturity data from 1991 shows that female squat lobsters reach maturity, as a population average, at intermediate sizes (ages).The 5 % plausibility regions and 95 % confidence intervals, as measures of uncertainty in maturity estimation, showed very s w a r interval estimates.The shape of the maturity curve corresponded to a stable population in terms of age structure.
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