Contribution to the Biology and Fishery of the Deep-Water Red Crab, Chaceon Affinis (A. Milne-Edwards & Bouvier, 1894) (Decapoda, Brachyura, Geryonidae) in Deep Waters of the Canary Islands (Central-East Atlantic)

Abstract

Two exploratory trap fishing surveys were carried out from February to April and from June to July 2003, respectively, at depths ranging between 300 and 1200 m, with the objective to assess deep fishery resources of the Canary Archipelago. Despite the fact that the deep-water red crab, Chaceon affinis is a virtually unknown species for the artisanal fishermen of the islands, it was relatively frequent in catches, as an indication of its abundance in deep waters off the archipelago. This crab was captured in the whole range of depths sampled, although its highest abundance was found between 600 and 800 m, on muddy-rocky bottoms. Moreover, significant differences were observed in the average weight and length, according to depth of capture, island of origin, and date of survey. In general, the b parameter of length-weight relationship indicates a negative allometric growth pattern, although in some cases it was not statistically different from isometry, particularly in males. Males were heavier, larger, and more abundant in catches than females. RESUMENSe realizaron dos campañas de pesca exploratoria de febrero a abril y de junio a julio de 2003, respectivamente, entre los 300 y 1200 m de profundidad con el objeto de evaluar los recursos pesqueros profundos del Archipiélago Canario. A pesar de que el cangrejo rey (Chaceon affinis) es una especie prácticamente desconocida para los pescadores artesanales de las Islas, fue relativamente frecuente en las capturas, prueba de su abundancia en las aguas profundas del Archipiélago. Este cangrejo fue capturado en todo el rango de profundidades muestreado, aunque su mayor abundancia se encontró entre los 600 y 800 m de profundidad, tanto sobre fondos fangosos como rocosos. Además, se observaron diferencias significativas en los pesos y tallas medias, según la profundidad de captura, isla y fecha de la campaña. En general, el exponente b de la relación talla-peso indicó un patrón de crecimiento alométrico negativo, aunque en algunos casos éste no fue estadísticamente diferente de la isometría, particularmente en machos. En las capturas, los machos fueron más pesados, grandes y abundantes que las hembras.

First record and preliminary information on the biology of the deep sea African crab, Chaceon gordonae (Ingle, 1985) (Brachyura: Geryonidae) in Saint Peter and Saint Paul Archipelago, Brazil

“…Males were more frequent than females in the present study, concurring with many studies on geryonids (Fernández-Vergaz et al, 2000;Pinho et al, 2001;López-Abellán et al, 2002;Guerrero & Arana, 2009;Castro et al, 2010), (Taggart et al, 2004). Additionally, sampling bias probably also exists with regard to male size, since smaller crabs are less likely to enter traps when large males are present (Taggart et al, 2004).…”

“…The unimodal size frequency for both males and females, however, appears to be a general pattern of the Geryonidae. According to López-Abellán et al (2002) and Castro et al (2010), this kind of length-frequency distribution in females may be due to a shorter period of moulting in immature specimens, when compared to those after maturing.…”