Basic characteristics of the population dynamic and state of exploitation of Moroccan white seabream Diplodus sargus cadenati (Sparidae) in the Canarian archipelago

Abstract

Summary Moroccan white seabream Diplodus sargus cadenati (n = 603) were caught off the Canary Islands from April 2000 to March 2001. Total length ranged from 46 to 404 mm. The subspecies was characterized as being dygynous with partial protandry. Overall ratio of males to females was 1 : 2.9. The reproductive season extended from December to May, with a peak in spawning activity in January–February. Fifty per cent maturity was reached at 201 mm total length in males and 216 mm in females. The length–weight relationship for all individuals was described by the following parameters: a = 0.000023, and b = 2.96, when length is given in millimeters and weight in grams. Fish of 0–12 years in age were found. The von Bertalanffy growth parameters for the entire population were: L∞ = 467 mm, k = 0.143 year−1 and t0 = −2.14 year. Growth parameters differed between males and females. For all fish, instantaneous rates of mortality were Z = 0.68 year−1, M = 0.31 ± 0.6 year−1 and F = 0.37 ± 0.6 year−1; the exploitation ratio was E = 0.54 ± 0.9. Length at first capture for all individuals was 173 mm. The stock exploited above is an assumed optimum.

Population structure, length-weight relationship and growth of white seabream, Diplodus sargus sargus (Linneaus, 1758), in Beymelek Lagoon, Turkey

“…Most were between 13 and 16 cm total length and smaller than 90 g in weight. These values were less than those of the Balearic Islands and the Iberian coast (western Mediterranean) (Morey et al., ), off the Canary Islands (Pajuelo and Lorenzo, ) and in the Gulf of Tunis (Mouine et al., ). Thus lagoon coastal area populations show different age structures, affecting the overall sex ratio.…”

“…This species behaves as a ‘cyclic migrant’, entering into lagoons after metamorphosis and spending the early stages of their life cycle in these environments. Juveniles recruit to shallow areas (<5 m), whereas adults are more abundant in the surf zone (Pajuelo and Lorenzo, ) in depths between 10 and 50 m, depending upon substrate availability (Harmelin‐Vivien et al., ). The adults are present in a diverse variety of habitats, including coastal rocky reefs, sandy bottoms and seagrass beds (Domingues et al., ).…”

Spatial variation in demography of an estuarine teleost: implications for population and fishery assessments

“…The Sparidae is a diverse family of fish exploited in fisheries in tropical and temperate waters worldwide (Gonçalves et al 2003, Grandcourt et al 2004, Pajuelo & Lorenzo 2004, Vitale et al 2011. A. australis occupies various habitats in estuaries and coastal waters across 20 degrees of latitude (19−30°S; 2200 km) along the east coast of Australia (Kailola et al 1993, Gray et al 1996, Kingsford 2002.…”

Age and growth of the sharpsnout seabream Diplodus puntazzo (Cetti, 1777) inhabiting the Canarian archipelago, estimated by reading otoliths and by backcalculation

“…This rise in water temperature could introduce changes in the metabolic activity of the individuals during spring and summer and could be the main factor responsible for opaque zone deposition. Pajuelo and Lorenzo (2001, 2002, 2003a, 2004, Buxton (1993, 1996) and Mann and Buxton (1997) also found that the opaque rings formation in the otoliths of different Diplodus species takes place during the rapid growth season. The available data suggest that the increase in seawater temperature affects the physiology of otolith growth of the Diplodus species and results in the formation of the annulus.…”