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

The ecology and life history strategy of the endangered cyprinid fish speci es Anaecypris hispanica in the intermittent streams of the Guadiana River c atchment 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 (<60 cm), and a water temp erature below 25<degrees>C. The species is short lived (maximum three years old) achieving a small size (<60 mm fork length) with rapid growth (<appro ximate to>40 mm) to maturity in its first year of life, and little growth t hereafter (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 oo cyte 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' selec ted life history strategy to survive the variability of the environmental c onditions prevalent in intermittent streams. However, alterations to habita t, flow regime through abstraction and river regulation, pollution and the introduction of exotic fish species have contributed to the demise of the s pecies across its natural range in southern Iberia. Concerted action is nee ded to conserve the few remaining habitats where the species survives, and rehabilitation of the degraded rivers where the species used to exist is di scussed.