Effects of breeder reuse on the reproductive potential of the signal crayfish (Pacifastacus leniusculus Dana. Astacidae) in culture

Abstract

The aim of this work was to evaluate the reproductive potential of the signal crayfish (Pacifastacus leniusculus Dana) in the second cycle under culture conditions. The experiment was carried out using 5,653 animals placed in six earthen ponds in August. Three treatments were performed, each in two ponds: breeder reuse (males and females used in the former reproductive cycle), female reuse (new males from the wild and females used in the former reproductive cycle) and new breeders (males and females from the wild). In April, close to hatching, egg-bearing females were transferred to the hatchery. Mortality of the reused breeders (around 30% of females and 41.4% of males) was significantly higher than that of the new breeders (11.4% of females and around 19.5% of males). The proportion of berried females close to hatching was significantly higher for the new ones (77.4% of the initial number), and the percentage of new females with a large quantity of eggs (63.6%) was higher than that of the reused females (25.6 and 20.9%). Differences among the percentages of females without eggs in the new breeders (11.2%) and the rest of the treatments (30.7 and 39.6%) were significant. The reproductive capacity of reused females was not improved by providing new males. Considering the number of females initially stocked into ponds, mean yield per new female was greater than that of the reused females, mainly due to the higher mortality recorded in the reused broodstock. Although the yield that can be obtained using the same breeders in two reproductive cycles drops in the second one, the production was not negligible.

The effect of male absence on the larval production of the spider crabMaja brachydactylaBalss, 1922

“…These results suggest that the presence of males has a negative effect on female fitness, and consequently, on seed production. Similarly, female mortality of the signal crayfish caused a decrease in the juvenile production when females were kept during two consecutive reproductive cycles in the presence of males (Celada, Antolin, Carral, Perez & Saez‐Royuela ). In the aquaculture context, reducing the mortality of females would extend the production lifetime of the broodstock, and would therefore optimize hatchery resources.…”