Age and growth of an Iberian cyprinodont, Aphanius iberus (Cuv. & Val.), in its most northerly population

Abstract

Age and growth of an Iberian cyprinodont, Aphanius iberus (Cuv. & Val.), in its most northerly population, La Rubina lagoon (Alt Emporda wetlands, NE Spain), was studied. The age groups for this Mediterranean population ( O + , 1 + and 2 + ) agree with those reported for the Atlantic population (R. Guadalquivir marshes), in the southern limit of the species distribution in the Iberian peninsula. Differences in age structure between these populations and the one previously studied in La Tancada lagoon (R. Ebro delta marshes) can be attributed to age estimation bias. Male A . iberus data appear to fit similarly to a Gompertz growth function and to a von Bertalanffy growth function, but L , was clearly underestimated. A Gompertz growth function was not a good fit for females, perhaps because female growth is clearly faster and less attenuated than male growth. The life history and growth pattern ofthis species is similar to that in other cyprinodontiform fishes, typified by a short longevity. The growth model of this species does not seem to fit types I and I1 of Sebens's classification, which are characteristic of fish.

Biology of the endangered cyprinodontidAphanius iberusin a saline wetland (SE Iberian Peninsula)

“…The population structure of A. iberus in Marchamalo wetland was formed by three age groups (0+, 1+ and 2+) in both sexes, similar to that observed in the most northerly population located in the Alt Empordà wetlands (García-Berthou & Moreno-Amich 1992). In the Ebro delta, however, the maximum age observed was 1+ (Vargas & De Sostoa 1997).…”

Interaction between the introduced eastern mosquitofish and two autochthonous Spanish toothcarps

“…Increases in orientations towards conspecifics were coincident with peaks of reproductive activity of both wild populations and the captive stocks of both species (Fernández-Delgado et al, 1988;García-Berthou & Moreno-Amich, 1992;Risueño et al, 1999a, b;Caiola et al, 2001). Furthermore, the observations well matched the descriptions of the initial stages of their courtship (Checa, 1982;P.…”

“…data). This is not a consequence of captivity or holding conditions for the same occurs in all wild populations studied so far (Fernández-Delgado et al, 1988;García-Berthou & Moreno-Amich, 1992;Vargas, 1993;Vargas & de Sostoa, 1997).…”

Food of an endangered cyprinodont (Aphanius iberus): ontogenetic diet shift and prey electivity

“…It originally inhabited a wide range of lowland waters but now-a-days its distribution is reduced to brackish and hypersaline waters in salt marshes and coastal lagoons. This is due to the impact of invasive species such as the poeciliid fish Gambusia holbrooki, habitat destruction by wetland desiccation, and water pollution (Garcı´a-Berthou & Moreno-Amich 1992;Doadrio 2001;Rinco´n et al 2002). The Atlantic populations of the Spanish toothcarp have recently been distinguished as a new species (A. baeticus) because of differences in morphometrics and genetics (Doadrio et al 2002).…”