Size composition, monthly condition factor and morphometrics for fishery-dependent samples of Rioraja agassizi (Chondrichthyes: Rajidae), off Santos, Southeast Brazil

• Autor(a) principal: Oddone,M. Cristina
• Data de Publicação: 2007
• Outros Autores: Amorim,Alberto F. de, Mancini,Patrícia L., Norbis,Walter
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Neotropical ichthyology (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1679-62252007000300021
• topic: Skates; Depth; Total length; Elasmobranch; Sex ratio

Specimens of Rioraja agassizi were collected monthly off Santos, Southeast Brazil, between latitudes 23º37'S and 27º40'S, from March, 2005 to March, 2006. A total number of 278 males and 1023 females were captured. Observed depth range was 10-120 m, being the species absent above 120 m. Sex ratio significantly favored females. The entire length range of R. agassizi was observed. Females ranged in length from 16.0 to 59.4 cm and males from 13.0 to 47.2 cm. Mean female length was significantly higher than that of males. For grouped length distributions, asymmetry patterns were observed in both sexes. Length-width functions were sexually dimorphic. Males with lengths < 24.5 cm were relatively wider than females. Length-total weight curves were significantly different than length-gutted weight ones, in both sexes. Females were heavier than males for a given TL class. The angular coefficient b was significantly &lt;3 (negative allometry) in the males, and also for the females with exception of spring when b was >3 (positive allometry). The monthly variation of the condition factor showed significant differences in both sexes.