Preprint volume - SIBM

Pre-print Volume –Posters
Topic 4: THE ELASMOBRANCHS
were present in the ovary (see Fig. 1b). The male was 162 cm total length; and 17,5 kg
weight. Both sharks showed a dorsal surface grey-brown, ventral surface light. Brown
vertical bars are present although not evident as in juveniles.
Conclusions – The species lives on shelf bottom over a restricted area (1,500 km of
coastline) of the Southwest Atlantic. Neonates are typically found off beach between 1
and 5 m depth, juveniles are found in inshore waters between 15 and 50 m, and adults
are found down to 50 m up to 250 m (Soto, 2001b). According to the literature gravid
females migrate to the coast at less than 20 m depth to give birth in October-December.
After they reach depth between 20 and 50 m, where mature males occur for mating.
The gestation period lasts 11-12 months. This endemic species occurs at low densities.
Trawl surveys carried out in north Argentina and Uruguay showed that biomass indices
decreased by 96% from 1994 to 1999. There is serious concern regarding further
declines in the absence of conservation and enforced management measures. In 2002
M. fasciatus was classified as a species threatened with extinction. The maximum size
reported for M. fasciatus are 147 cm TL in males and 158 cm TL in females (Soto,
2001a; Soto and Mincarone, 2004). The sizes of the specimen reported in this note are
the largest of the literature (female 177 cm, male 162 cm). The findings of very large
individuals just three years ago seem in contrast with the much depleted status assessed
for the stock. This contrasting result might be interpreted as the effect of an increase in
fishing efficiency to explore/exploit wider and wider fishing-grounds.
Aknowledgements - We are grateful to the following fisherman: Carlos Sena, Julio Sevallos, Nestor
and Danubio Oliveira, Punta del Diablo, Rocha, Uruguay. We also thank to Mr. Wilson Enrique
Veiga who provided the first specimen.
References
COMPAGNO L.J.V. (1984) – FAO Species Catalogue. Vol. 4. Sharks of the World. An annoted and
illustrated catalogue of shark species know to date. Part 2. Carcharhiniformes FAO Fish. Synop.
(125), 4, 2: 251-655.
SADOWSKY V. (1977) – Primeiro registro de ocorrencia de especimes adultos de cação-malhado,
Mustelus fasciatus (Garman, 1913). Ciencia e Cultura (Suppl.), 29 (7): 801.
SOTO J.M.R. (2001a) – Annotated systematic checklist and bibliography of the coastal and oceanic
fauna of Brazil. I. Sharks. Mare Magnum, 1 (1): 51-120.
SOTO J.M.R (2001b) – Distribution and reproductive biology of the Striped smooth-hound Mustelus
fasciatus (Garman, 1913) (Carcharhiniformes, Triakidae). Mare Magnum, 1 (2): 129-134.
SOTO J.M.R., MINCARONE M.M. (2004) – Collections of the Museu Oceanografico do Vale do
Itajai: 1 Catalog of Cartilaginous Fishes. (Mixini, Cephalaspidomorphi, Elasmobranchii,
Holocephali). Mare Magnum, 2 (1-2): 1-125.
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