Estimation of Megrim (Lepidorhombus whiffiagonis) growth parameters, for males and females, from the I.C.E.S division VII: fitting to the V. BERTALANFFY model using, resampling techniques as well as several adjustable central values (mean, median and mode length at age)

Reading Megrim otoliths (Lepidorhombus whiffiagonis), caught in the I.C.E.S division VII, provided an estimate of the relationship between length and age for fishes, each sex separately. The Von BERTALANFFY model (1938) has been widely employed to describe Megrim growth in length. In this, because of the small sample size (only 184 otoliths of males and 342 of females), and the difficulty in assessing the age of some fishes, data have been fit to the growth model using, resampling techniques (Bootstrap), as well as several central values of fitting (mean, median and principal mode length to age). The various results are presented and discussed.Les lectures des otolithes de Cardines (Lepidorhombus whiffiagonis), capturees dans la division C.I.E.M VII, ont permi de determiner la relation entre la longueur et l'âge des poissons de chaque sexe. Le modele de Von BERTALANFFY (1938) a été retenu pour decrire la croissance en longueur.Devant le faible nombre d'otolithes lus (184 pour les mâles et 342 pour les femelles) et la difficulté à estimer l'âge de certains poissons, les données obtenues ont été ajustées au modele de croissance en utilisant, des techniques de rééchantillonnage (Bootstrap), et plusieurs valeurs centrales d'ajustement (moyenne, mediane et mode principal des distributions des longueurs aux âges). Les différents résultats sont présentés et discutés

Cod (Gadus morhua) Migrations in the Gulf of St. Lawrence and Areas South of Newfoundland

During the years 1975, 1976, 1980 and 1982 cod (Gadus morhua) tagging experiments were conducted, inside the Gulf of St. Lawrence and outside in areas south of Newfoundland, by French scientists from IFREMER St. Pierre and Miquelon laboratory, in order to study the population distribution and migration and to complement the experiments carried out by Canadian scientists. The analysis from all recoveries and results from these experiments are presented here. The relevance is that the comparison with the Canadian results would lead to a better understanding of the cod stock exchanges in the area. The migratory patterns were believed to be mainly a response to seasonal environmental condition changes. In winter the cod were noted to migrate from the central Gulf of St. Lawrence southwards to outside areas, and the reverse process occurred in spring. On St. Pierre Bank most of migrations were observed to take place to and from the offshore and inshore waters. Most of the cod on St. Pierre Bank were believed to remain in the area. Although some exchanges with the Grand Bank cod population were noted, the level of this migratory process which was variable from year to year seemed generally low

Approche de la dynamique de stocks accessoires : le cas des lingues (Molva sp.) exploitees par la flotille industrielle lorientaise

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc