Population Structure, Growth And Reproduction
(Almeida, Eduardo Machado de)
Population structure, growth and reproduction of Maurolicus stehmanni Parin & Kobyliansky, 1993 (Teleostei: Sternoptychidae) in south-eastern and south Brazilian economic exclusive zone.Maurolicus is a genus of mesopelagic fish very abundant in thesouth-eastern and south Brazilian Economic Exclusive Zone. The materialof this study was sampled by mid water trawl during cruises of R/VAtlântico Sul in winter of 1996, autumn of 1997 and spring of 1997,between 100 and 1500 meters depth, from latitudes of 22° to 35° S. Themeristic and morphological analysis of 120 specimens collected in 4distinctive points, has indicated the occurrence of M. stehmanniParin & Kobyliansky, 1993 in the area. Through the vertical andhorizontal distribution of the catches it was verified that thisspecies is associated with the shelf break, staying in depths higherthan 200 m during the day, migrating to lower depths at night as theluminous intensity falls. The length frequency and the proportionbetween youngs and adults showed that the recruitment occured duringthe periods surveyed. By means of young-adult proportion by length avalue of L50 about 32 mm was estimated. The study ofgonadossomatic relationship, gonadal maturity frequency and ?K(difference between total and somatic condition factor) indicated that M. stehmannipresented reproductive activity in the area during all the sampledseasons. There is a linear relationship between the standard length andthe otolith radius, however the periodicity of the zone formation wasnot identified, which did not permit appropriate estimates of thegrowth parameters. The L? of 53 mm and k of 0,9 year?1 were estimated using ELEFAN I routine (FISAT) based on length frequency data, indicating that M. stehmanni attains maturity around its first year of life.
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