Reproduction and growth of Barbus haasi in a small stream in the N. E. of the Iberian peninsula
Aparicio, Enric; de Sostoa, Adolfo
Archiv für Hydrobiologie Volume 142 Number 1 (1998), p. 95 - 110
published: Apr 27, 1998
ArtNo. ESP141014201006, Price: 29.00 €
We studied age, growth and reproduction of Barbus haasi, an endemic cyprinid of the Northeast Iberian peninsula, in a small Mediterranean stream of the Llobregat river basin. The females live for 8 years (7+) while the males only live for 7 years (6+). The males grow more slowly than the females; the maximum fork lengths observed were 153 mm in males and 220 mm in females. The equation of Von Bertalanffy that defines growth is: males: LT = 208.227 [l-e-0.173(t-0.470]; females: LT = 448.897 [l-e0.085(t+0.236)]. This growth rate is one of the lowest recorded for a European barbel population. The overall sex-ratio (265 males : 185 females) differed significantly from equality. Sexual maturation occurs from the age class 0+ to 2+ in males, and from 1+ to 3+ in females. The females have multiple spawning, releasing 2 to 5 egg batches depending on their size, such that the largest females spawn more batches than the small ones. The regression between fecundity (Fa) and fork length (FL, mm) is: ln (Fa) = -7.97+ 3.26 · ln (FL). The reproductive effort of the females increases progressively with age. The timing and length of the breeding season are related to periods of high stream flow. The life history pattern of this population is characterised by reduced longevity, precocious maturity, multiple spawning and high fecundity, these features being the result of adaptation to the characteristic instability of the river systems of the Mediterranean region.