INDIVIDUAL GROWTH IN THE PATAGONIAN GASTROPOD BUCCINANOPS COCHLIDIUM (NASSARIIDAE): A FIELD TAGGING-RECAPTURE EXPERIMENT

AVERBUJ, A.; ESCATI-PEÑALOZA, GABRIELA; PENCHASZADEH, P.E.

MALACOLOGIA

INST MALACOL

Lugar: Philadelphia; Año: 2015 vol. 59 p. 121 - 133

0076-2997

This study describes the growth of individuals in a population of Buccinanopscochlidium (Nassariidae) through the identification of the best-fittinggrowth model based on field tag-recaptured experimental data. A total of 48individuals (8.6% of total tagged snails) were recaptured, after 2 to 25months, representing a remarkable proportion for a field experiment withinfaunal organisms. The sex ratio was not different from 1:1. Males measuredbetween 63.4 and 89.0 mm (n= 25) while females measured between 50.9 and 103.2mm (n= 23) in shell length. The maximum annual length increment obtained was35.74 mm, mean annual length increment was 4.51 and 8.43 mm for females andmales, respectively. Because no statistically significant differences werefound between male and female growth increments, a single growth model wasfitted to the entire data set. Regarding individual growth modeling, theinverse Logistic (iLog) model adequately described the pattern in the data, butshowed heteroscedasticity. A refitting of iLog using weighted least squares,weighted inverse Logistic (iLog*), better fit the data (and agrees withbiological knowledge of B. cochlidium) than the inverse Logistic (iLog),exponential (Exp), von Bertalanffy (vB) and Gompertz (Gz) models. Estimatedparameters for the iLog* model were Max dL: 27.83, L50: 69.89, L95:93.36. The results of this study are valuable for assessment of snail fisheriesin Patagonia and suggest fisheries management policies for a sustainable futureof this potential stock prior to extensive exploitation.