Reproduction and size at first maturity in a Mediterranean exploited <em>Callista chione</em> bivalve bed

Abstract

Summary:The smooth clam Callista chione is an Atlantic-Mediterranean species that is commercially exploited in several European countries. Several aspects of its reproduction were studied in a coastal location of the northwestern Mediterranean as a tool for sustainable fisheries management. Gonadal development was classified into 6 different stages, ranging from immature to degradation of the remaining sexual structures. Results showed that C. chione was able to reproduce throughout the year but a main spawning period occurred in spring. First records of hermaphrodites were found for this species. The mature spermatozoa measured 4. Keywords: gonads; first maturity; hermaphroditism; Veneridae; commercial mollusks. Reproducción y talla de primera madurez en un banco de Callista chione explotado en el MediterráneoResumen: La concha fina Callista chione es una especie atlántico-mediterránea comercialmente explotada en distintos paí-ses europeos. Se estudiaron varios aspectos de su reproducción en una localidad costera del noroeste Mediterráneo como herramienta para la gestión sostenible de su pesquería. El desarrollo gonadal se clasificó en 6 estadios distintos, que engloban desde individuos inmaduros a la degradación de las estructuras sexuales remanentes. Los resultados mostraron que C. chione se podía reproducir durante todo el año con un periodo de máxima puesta en primavera. Se observaron hermafroditas de esta especie por primera vez. Los espermatozoos maduros midieron 4.70±0.66 µm (sin el flagelo) incluyendo un corto acrosoma de 0.75±0.09 µm. La pieza media de los espermatozoos estaba compuesta por 5 mitocondrias. Los ovocitos maduros median entre 60-80 µm de longitud. La talla de primera maduración (SL 50

Gametogenic cycle of the rough cockle <em>Acanthocardia tuberculata</em> (Mollusca: Bivalvia) in the M’diq Bay (SW Mediterranean Sea)

“…These parameters are known to directly affect the physiological status of bivalves, regulating gametogenic cycles and spawning, among other physiological processes (Galimany et al 2015). In agreement with these studies, a strong negative correlation between temperature and seasonal variation of the OD (r=-0.67; P<0,005) was observed in this study.…”

“…Hence, the aim of this paper is to provide information on the reproductive cycle of A. tuberculata on the west Mediterranean coast of Morocco and to suggest a closed season and the minimum commercial size for a more sustainable management of this fishery. A correct estimate of the size at first maturity is a common tool for adopting the legal minimum size allowed for fishing and was succesfuly suggested by several authors to implement suitable fishery management measures (Moura et al 2008, Elhassni et al 2010, Galimany et al 2015.…”

Effects of fishing closure and mechanized clam dredging on a Callista chione bed in the western Mediterranean Sea

“…This study also revealed changes in important biological parameters for the conservation of C. chione (e.g., size, length-weight relationship, density and size structure) between 2005 and 2020. Changes in the same C. chione population were also previously reported by Galimany et al (2015) (Kenchington et al, 2003) but not in shellfish species.…”

“…It is a long-living bivalve that can live over 40 years (Forster, 1981) and its shell length can reach 100 mm (Poppe and Goto, 1993). C. chione is able to reproduce throughout the year but the main spawning period occurs in spring on the Catalan coast (Galimany et al, 2015). Its minimum legal size of capture is 60 mm length in the European Union.…”