Mating and spawning of freshwater crayfish, Austropotamobius pallipes Lereboullet, under laboratory conditions

Abstract

The study includes mating and spawning data of freshwater crayfish, Austropotamobius pallipes Lereboullet, obtained in four consecutive years (1987)(1988)(1989)(1990). A total number of 586 wild-caught female A. pallipes in the 21-65 mm to 45-60mm carapace length (CL) size were held under laboratory conditions at different dates in September-October. Initial densities at mating time were 21 and 24 erayfish/m' with a 1:2 malc:female ratio. High percentages of mating were obtained (97 4-100%) exeept in 1989 (57-5%). ln all years, most of the maiings (90%) were concentrated in a period of 8-12 days with mean water temperatures between 12''C and 13 5°C. Spawning took place a few days after mating (minimum 2 days, maximum 14 days) at mean water temperatures between H^^C and lO-B^C. In the firet 3 years, almost 100% of mated females spawned. However, in the fourth year (1990), when the mean size of erayfish was smaller, only 72-4% of mated females spawned. The mean number of pteopodal eggs was 64 (maximum 220, minimum 18). Egg diameter ranged between 2-30 and 3 25 mm (mean value 2-78 mm). Pleopodal egg number was positively correlated with earapaee length (r = 0 72). Correspondence: Dr Jos<S M. Carral. Departamento dc Producci6n Animal, Universidad de Lc6n. Campus de Vegazana. 24071 Le6n, Spain. 721 722 J.M. Carral et al.

The Relationship Between Female Size and Egg Size in the Freshwater Crayfish Austropotamobius Torrentium

“…Values of correlations between measured parameters are shown in Table III while the relations between females and their eggs are shown on Figures 1a, b, c, and d. The existence of positive correlation between female size and total number of eggs they produce is known from the literature (HUNER and LINDQVIST, 1991). Contrary to HARLIOĞLU (1996) andHARLIOĞLU andTÜRGÜLÜ, (2000), and similar to RHODES and HOLDICH (1982), BREWIS and BOWLER (1985), KÖKSAL (1988), TAUGBØL, SKURDAL and FJELD (1988), CARRAL et al (1994, 2004, STUCKI (1999), and EVERSOLE et al (2002, we found positive correlation between female size and number of eggs. Correlation coefficients reported by RHODES and HOLDICH (1982), BREWIS and BOWLER (1985) and CARRAL et al (1994) showed a great variability (0.39-0.93).…”

“…Contrary to HARLIOĞLU (1996) andHARLIOĞLU andTÜRGÜLÜ, (2000), and similar to RHODES and HOLDICH (1982), BREWIS and BOWLER (1985), KÖKSAL (1988), TAUGBØL, SKURDAL and FJELD (1988), CARRAL et al (1994, 2004, STUCKI (1999), and EVERSOLE et al (2002, we found positive correlation between female size and number of eggs. Correlation coefficients reported by RHODES and HOLDICH (1982), BREWIS and BOWLER (1985) and CARRAL et al (1994) showed a great variability (0.39-0.93). CARRAL et al (2004) explains that probable cause of correlation coefficient variability is related to the different number of animals, the number of populations, number of reproductive season and the phase of embryonic development taken into consideration.…”

“…(MANKAMPA and CHAISEMARTIN, 1996) that eggs attached to the pleopodal appendages present a good basis for estimation of potential young production, and that low biotic potential observed within some females is a consequence of poor trophic niche, and abiotic factors (temperature, pH) (ABRAHAMSSON, 1966). Also females lose their eggs during the egg-bearing period due to poor egg attachment, disturbance, fungal infections and aggressive contacts with other crayfish (CARRAL et al, 1994;REYNOLDS, 2002;MAGUIRE et al, 2002, CARRAL et al, 2004. As a result, including females with just a few eggs attached to their pleopodal appendages into the analyses would not yield realistic results.…”

“…Freshwater crayfish, especially astacids, have low fecundity, with values usually fewer than 250 eggs (BROWN and BOWLER, 1977;MOMOT, 1991;CARRAL et al, 1994;REYNOLDS, 2002;POLICAR, 2004). Fecundity is generally proportional to female size and number of eggs can differ markedly between different populations of the same species due to environmental conditions (REYNOLDS, 2002;SKURDAL and TAUGBØL, 2002).…”

“…In crayfish reproduction, one of the main factors affecting fecundity is egg size. It is known that an increase in egg size causes decrease in fecundity (RHODES and HOLDICH, 1982;BREWIS and BOWLER, 1985;CARRAL et al, 1994;CARRAL et al, 2004), but it is not known what is the relation between female size and egg size. Therefore, in this research we dealt with this question.…”