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Volume 43 - Number 1 - 2008

Spatial and temporal variation of length and sex composition of the narrownose smooth-hound Mustelus schmitti Springer, 1939 in the trawl fishery off the oceanic coast of Uruguay during 2004

Inés Pereyra1, Luis Orlando1, Walter Norbis1 y Laura Paesch1


1Dirección Nacional de Recursos Acuáticos (DINARA), Departamento de Biología Pesquera, Constituyente 1497, C. P.: 11200-P.O. Box 1612, Montevideo, Uruguay



This study analyses the seasonal fisheries and sexual proportion of the narrownose smooth-hound Mustelus schmitti from the Uruguayan oceanic coast. The maximum catches took place during the fall. Of a total of 2105 individuals, 1483 were males and 622 females, being females larger than males. Females were dominant at maximum depths of 50 m (inner shelf), whereas males occupied major depths of 50 m (outer shelf). The great proportion of mature females on the inner shelf during spring and summer, and mature males in summer are related to the mating, ovulation and delivery time as previously proposed for this shark in this area. The length in which 50% of the females were retained was below or on the length of sexual maturity of the narrownose smooth-hound, indicating that these are more affected by the fishing activity. Nevertheless, an important fraction of the population that distributes on the inner and outer shelf during the time of parturition, ovulation and mating would be protected in spring and summer by the establishment of fishing bans of the fishes Cynoscion guatucupa and Merluccius hubbsi.

Key words: Coastal shark, size composition, fishery, Uruguayan coastal shelf, southwestern Atlantic




1Laboratorio de Zooplancton, Instituto de Ciencias del Mar y Limnología,Universidad Nacional Autónoma de México. A. P. 70-305, 04510 México, D. F. México
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