Life history traits of the endangered Iberian cyprinid Anaecypris hispanica and their implications for conservation

Abstract

The ecology and life history strategy of the endangered cyprinid fish species Anaecypris hispanica in the intermittent streams of the Guadiana River catchment in Southern Portugal were examined. A. hispanica occurs mainly in smaller streams with high dissolved oxygen concentrations (>9 mg/L), coarse substratum (gravels and cobbles), shallow depth (<60cm), and a water temperature below 25 °C. The species is short lived (maximum three years old) achieving a small size (<60mm fork length) with rapid growth (= 40 mm) to maturity in its first year of life, and little growth thereafter (10-15 mm/yr). The species spawns for the first time early in its second year of life (April-May period). Owing to the different maturing oocyte sizes in ovaries, it seems to be a fractional spawner, laying a small number of oocytes (<100) in each batch. The species has adopted a r' selected life history strategy to survive the variability of the environmental conditions prevalent in intermittent streams. However, alterations to habitat, flow regime through abstraction and river regulation, pollution and the introduction of exotic fish species have contributed to the demise of the species across its natural range in southern Iberia. Concerted action is needed to conserve the few remaining habitats where the species survives, and rehabilitation of the degraded rivers where the species used to exist is discussed.