Life history pattern of the endangered Valencia toothcarp, Valencia hispanica (Actinopterygii: Valenciidae) and its implications for conservation
Caiola, Nuno Alberto; Vargas, Maria Josep; de Sostoa, Adolfo
published: Jan 20, 2001
ArtNo. ESP141015003007, Price: 29.00 €
The life history pattern of the most northern population of an endangered endemic fish from the Iberian Peninsula, Valencia hispanica, was studied in Catalonia. Maximum observed ages were 4+ in females, and 3+ in males. The seasonal growth period started in June and continued until October. Females lived longer and reached larger sizes than males. The largest sizes found were 71 mm versus 67mm for females and males, respectively. V. hispanica is a multiple spawner that releases small batches of oocytes (varying from 10 to 30) between April and July. The release of oocytes is greatest in May and June. After reproduction, the number of parental individuals decreased. The relationships between fecundity (F) and total length (Lt, mm), total weight (Wt, g) and gonad weight (Wg, g), were: F = 15.735 Lt - 432.91; F = 111.70 Wt + 101.17; F = 717.36 Wg + 220.80. To examine the drastic regression of this species, its life history tactics were compared with those of another protected endemic cyprinodontid species (Aphanius iberus) which still inhabits areas once occupied by the two species. The biology of the Valencia toothcarp is characterised by slow growth, low reproductive effort, relatively late maturity, high longevity and multiple spawning. This seems to be an inappropriate life history strategy for small fish species in unstable environments with high human pressure, such as Mediterranean estuaries (where the species was once abundant) which are characterised by high, variable or unpredictable adult mortality. Some conservation measures and suggestions for a recovery programme are discussed.