Life-history of the meagre Argyrosomus regius in the Gulf of Cádiz (SW Iberian Peninsula)

Argyrosomus regius is an important fishing resource in the Gulf of Cádiz and from the Gulf of Guinea to the Bay of Biscay, including the Mediterranean Sea. Large adult meagres, c. >110-cm total length (LT), apparently reproduce in coastal brackish waters. The objective of this study was to analyse maturity and growth in this species, and together with the analysis of landings, formulate a conceptual model of its life-history along the Spanish coast of the Gulf of Cádiz. Large A. regius were landed near estuaries from March to August, all of which were mature. Small (20–70 cm LT) A. regius were landed all year round; females were immature, whereas 26% of the males presented precocious maturation. The estimated length-at-first maturity was 61.6 cm for males and was inferred to occur within the 70–110 cm range in females. The estimated growth constant k and L∞ of the von Bertalanffy model were 0.15 year−1 and 171.9 cm LT respectively. Estimates of relative yield-per-recruit suggest that growth overfishing is likely to occur under the current absence of regulations. According to the proposed conceptual model, A. regius spawns in estuaries from March to August. Early stages inhabit the estuaries and then recruit to coastal waters where they stay during the first 2–3 years of life. Thereafter, intermediate–size A. regius (70–110 cm LT) become unavailable to the local fishery. Once they mature, they migrate back to spawn, and to be fished again by the fishery.