Functional Maturity and Terminal Molt of Male Snow Crab, Chionoecetes opilio

Abstract

Bivariate and multivariate analyses of allometric relationships between chela size and carapace size of snow crab, Chionoecetes opilio, show that mature males are recognizable by morphometry. The most simple procedure is to plot logarithms of chela height (Ch) against logarithms of carapace width (Lc). Data from mature and immature males fit into two distinct ellipses with parallel major axes. The discriminant function Y = −0.78893 loge. Lc + 0.614488 logeCh + 1.76051 will assign individuals to the correct groups in 99% of cases (for mature males: Y > 0). Spermatophores are present in the vasa deferentia of all males larger than 60 mm Lc. The molt to morphometric maturity occurs later at Lc sizes ranging from 60 to 120 mm; it is identified as final. Only morphometrically mature males larger than 96 mm Lc have been observed to mate efficiently with multiparous females in intermolt and be functionally mature. In the catch, as many as 40% of males larger than the minimal legal size of 95 mm can be immature.

Maturidade sexual em Callinectes ornatus Ordway, 1863 (crustacea: decapoda: portunidae) no litoral de Ilhéus, BA, Brasil

“…A sincronia entre a maturidade fisiológica e morfológica é uma estratégia reprodutiva que pode fornecer um maior número de indivíduos adultos capazes de copular, otimizando assim o esforço reprodutivo (Cobo & Fransozo, 2005). Entretanto, nem sempre a maturidade morfológica coincide com a maturidade gonadal do indivíduo, pois alguns braquiúros podem apresentar características externas de adultos sem apresentarem ainda gônadas maturas, ou vice-versa (Sastry, 1983;Conan & Comeau, 1986;Choy, 1988). Tal padrão foi observado em fêmeas de C. ornatus por Haefner (1990) Holthuis, 1967.…”

Determinação da maturidade sexual de Ucides cordatus (Crustacea, Brachyura, Ucididae) em duas áreas de manguezal do litoral sul de Pernambuco, Brasil

“…(WENNER et al, 1974, PRASAD & NEELAKANTAN, 1990FREIRE et al, 1991), enquanto o outro é baseado no surgimento dos caracteres sexuais secundários (HAEFNER, 1990;CASTIGLIONI & NEGREIROS-FRANSOZO, 2004;PINHEIRO & HATTORI, 2006). Para algumas espécies de caranguejos o tamanho de maturidade segundo estes métodos não coincide (CONAN & COMEAU, 1986;CHOY, 1988;LÓPEZ-GRECO & RODRÍGUEZ, 1999). Assim, a determinação do tamanho na primeira maturação pode ser comprometida quando se leva em consideração apenas aspectos da morfologia externa.…”

Size at morphological maturity of Ucides cordatus (Linnaeus, 1763) (Brachyura, Ocypodidae) in the Laranjeiras Bay, Southern Brazil

“…Crab Ucides cordatus (Linnaeus, 1763) is one of the commonest species in the mangrove ecosystem of the Western Atlantic (Costa, 1979), proving to be of great economic importance for capture and consumption in different regions, especially in Northern-Northeastern Brazil (Fausto-Filho, 1968;IBAMA, 1994). Studies on relative growth for this species have been done only in relation to the carapace length (Alcântara-Filho, 1978;Castro, 1986;Branco, 1993), contrasting with studies carried out on other commercially explored Brachyura, such as the Portunidae (Davidson and Marsden, 1987;Haefner, 1990;Sumpton, 1990;Pinheiro and Fransozo, 1993;Gonzáles-Gurriarán and Freire, 1994;Knuckey, 1996;Pinheiro and Fransozo, 1998) and Majidae (Somerton, 1981;Conan and Comeau, 1986;Comeau and Conan, 1992;Paul and Paul, 1995;Sampedro et al, 1999), where a larger number of relationships were analyzed. Relative growth and size at maturity are very important aspects for the better understanding of the Brachyura reproductive process.…”