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Doctoral Thesis
DOI
https://doi.org/10.11606/T.21.2006.tde-15082006-103247
Document
Author
Full name
Luiz Miguel Casarini
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2006
Supervisor
Committee
Petrere Junior, Miguel (President)
Cergole, Maria Cristina
Menezes, Naercio Aquino
Silva, Antonio Olinto Avila da
Wongtschowski, Carmen Lucia Del Bianco Rossi
Title in Portuguese
"Dinâmica populacional de raias demersais dos gêneros Atlantoraja e Rioraja (Elasmobranchii, Rajidae) da costa sudeste e sul do Brasil"
Keywords in Portuguese
crescimento
mortalidade
pesca
raias
rendimento
Abstract in Portuguese
Analisaram-se as proporções de Rioraja agassizi, Atlantoraja cyclophora, A. platana e A. castelnaui na categoria “raias-emplastros", nos desmbarques de 11 embarcações da pesca comercial, de arrasto duplo de portas e de parelhas, totalizando 358 lances realizados em 20 viagens. Elas atuaram entre as isóbatas de 10 e 430 m e entre os paralelos 23° S (Estado do Rio de Janeiro) e 31° S (Estado do Rio Grande do Sul), de 1995 a 1997 e de 2001 a 2003. Entre as espécies estudadas, A. cyclophora foi a mais freqüente nos lances realizados entre 60 e 265 m de profundidade, com ampla distribuição entre 23° 30’ S e 27°20’ S. As análises das pescarias sugerem que a profundidade e a latitude, entre outras variáveis, foram importantes apenas na captura de A. cyclophora. As carcaças foram desembarcadas em três tipos de cortes, a partir dos quais o peso corporal foi estimado. Também foram avaliadas as estruturas populacionais das quatro espécies. Os estimadores dos parâmetros de crescimento, largura de disco (LD) de primeira maturação sexual e taxa de mortalidade natural (M) foram calculados para machos e fêmeas, respectivamente: R. agassizi LD = 289 mm e 425 mm; K= 0,142 e 0,078 ano-1; t0= -1,653 e -1,811 anos; LD50 = 270 e 330 mm, M = 0,061 e 0,052 ano-1; A. cyclophora LD = 478 e 518 mm; K= 0,077 e 0,073 ano-1; t0= -4,518 e -4,485 anos; LD50 = 355 e 415 mm, M = 0,085 e 0,085 ano-1; A. platana LD = 733 e 823 mm; K= 0,057 e 0,052 ano-1; t0= -1,267 e -1,225 anos; LD50 = 500 e 550 mm, M = 0,061 e 0,021 ano-1; A. castelnaui LD = 794 e 1004 mm; K= 0,066 e 0,046 ano-1; t0= -1,978 e -2,235 anos; LD50 = 670 e 740 mm, M = 0,069 e 0,047 ano-1. Em alguns anos, o modelo relativo de rendimento-por-recruta resultou em valores próximos ou superiores aos pontos de referência biológica para machos de R. agassizi, e fêmeas de A. platana e de A. castelnaui. As taxas de explotação e mortalidade por pesca de A. cyclophora foram crescentes entre 2001 e 2003.
Title in English
Populational dymanics of skates genera Atlantorala and Rioraja (Elasmosbranchii, Rajidae) of Southeastern and Southern Coastal of Brazil
Keywords in English
fisheries
growth
mortality
skates
yield
Abstract in English
The proportions of the skates Rioraja agassizi, Atlantoraja cyclophora, A. platana and A. castelnaui landed by commercial fishing boats were analyzed. Data were collected from 358 hauls of 20 trips made by 11 double-otter trawlers and pair-trawlers. Fisheries were carried out between 10 and 430 m deep and from 23° S (State of Rio de Janeiro) to 31° S (State of Rio Grande do Sul) between 1995-1997 and 2001-2003. A. cyclophora was the most frequent in all hauls between 60 and 265 m deep among the studied species, with a wide distribution between 23°30’ S and 27°20’ S. The analyses of the fisheries suggested that depth and latitude, along with other variables, have importance only for A. cyclophora catches. The skates carcasses were landed in three types of cuts from which the body weight was estimated. The population structures of the four species were also evaluated. The growth parameters estimates, the disc width (DW) at first sexual maturation and the instantaneous natural mortality rate (M) for males and females were, respectively: R. agassizi: DW = 289 mm and 425 mm; K= 0,142 and 0,078 year-1; t0 = -1,653 and -1,811 years; DW50 = 270 and 330 mm, M = 0,061 and 0,052 year-1; A. cyclophora: DW = 478 and 518 mm; K= 0,077 and 0,073 year-1; t0= -4,518 and -4,485 years; DW50 = 355 and 415 mm, M = 0,085 and 0,085 year-1; A. platana: DW = 733 and 823 mm; K= 0,057 and 0,052 year-1; t0= -1,267 and -1,225 years; DW50 = 500 and 550 mm, M = 0,061 and 0,021 year-1; A. castelnaui: DW = 794 and 1004 mm; K= 0,066 and 0,046 year-1; t0 = -1,978 and -2,235 years; DW50 = 670 and 740 mm, M = 0,069 and 0,047 year-1. In some years, the relative yield-per-recruit model resulted values similar or higher than the biological reference points estimated for males of R. agassizi and females of A. platana and A. castelnaui. The exploitation ratio and the instantaneous fishery mortality rate for A. cyclophora increased between 2001 and 2003.
 
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Publishing Date
2006-08-28
 
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