Additional supply of decapsulatedArtemiacysts for various periods in intensive rearing of juvenile crayfish (Pacifastacus leniusculus, Astacidae)

Abstract

Key-words: astacid crayfish, juvenile, feeding, stocking densityThe additional supply of live feeds such as Artemia remains indispensable in juvenile astacid rearing from the start of independent life. Considering that cost and work could be reduced by restricting this supply, a 100-day experiment was carried out with stage 2 Pacifastacus leniusculus to evaluate the effects of different administration periods of decapsulted Artemia cysts as supplement to a dry diet at two stocking densities. Using a bifactorial design, six treatments differing in the time at which the cysts were withdrawn (after 20, 30 or 50 days of experiment) and the stocking density (100 or 200 crayfish·m −2 ) were conducted. Survival rates did not show significant differences among groups, with final figures averaging 81%. Crayfish receiving cysts up to day 50 showed faster growth (around 13.8 mm carapace length and 610 mg weight at the end of the experiment) than the rest, significant differences being recorded from day 60 of experiment onwards. The 20-day and 30-day supplies resulted in similar growth values. There were no significant differences in survival or growth between 100 and 200 crayfish·m −2 . This study shows that decapsulated Artemia cysts can be withdrawn at day 20 (allowing to feed a dry diet as the sole food thereafter) and that faster growth can be obtained if cysts are supplied up to day 50. Furthermore, a stocking density of 200 crayfish·m −2 can be advised under the mentioned feeding conditions.

Effect of Different Feed and Stocking Density on Survival and Growth Performance of Astacus leptodactylus (Esch., 1823) Juveniles

“…According to the results of these studies, the researchers advised to use the live feed as supplement from the onset of external feeding to guarantee the viability of juvenile crayfish. González et al (2008), supplementing a dry diet with live Artemia nauplii in excess, obtained good results (1283 mg weight, 4459 % weight gain and 3.82 % SGR) for juvenile Pacifastacus leniusculus. González et al (2011) indicated that the juvenile crayfish (P. leniusculus) receiving decapsulted Artemia cysts up to day 50 as supplement to a dry diet showed a faster growth (averaging 13.8 mm carapace length, 610 mg weight 3.05 % day −1 SGR) at the end of the experiment.…”

“…Zaikov et al (2000), used four different diets for A. leptodactylus during up to 1 month of age under 4 diet variants: zooplankton, feed mixture, meat and soyabean meal, and reported the best results of SGR in A. leptodactylus fed with zooplankton diet (3.56 %) and fed mixture diet (3.15 %). González et al (2008), supplementing a dry diet with live Artemia nauplii in excess, obtained 3.82 % SGR for juvenile P. leniusculus.…”

“…González et al (2008), supplementing a dry diet with live Artemia nauplii in excess, obtained good results (1283 mg weight, 4459 % weight gain and 3.82 % SGR) for juvenile Pacifastacus leniusculus. González et al (2011) indicated that the juvenile crayfish (P. leniusculus) receiving decapsulted Artemia cysts up to day 50 as supplement to a dry diet showed a faster growth (averaging 13.8 mm carapace length, 610 mg weight 3.05 % day −1 SGR) at the end of the experiment. In contrast to these results, the commercial trout feed used in the present study resulted in a better growth performance (28.68 mm total length and 653 mg alive weight) than live feed.…”

“…Several studies have been carried out under controlled conditions to evaluate the effect of feed on growth and survival of crayfish juveniles and a wide variety of foods have been tested in juveniles from the onset of exogenous feeding. Artemia, Chlorella, chironomid larvae, Daphnia, earthworms, fresh fish meat, aquatic plants and vegetables have been tried by Köksal (1985), Celada et al (1989Celada et al ( , 1993, Taugbol and Skurdal (1992), Köksal et al (1992), Blake et al (1994), Oliveira and Fabiao (1998), Verhoef et al (1998), Verhoef and Austin (1999), Zaikov et al (2000), Sáez-Royuela et al (2001, 2007, Savolainen et al (2003), González et al (2008). Besides the exogenous feeding, commercial feeds for crustacean and fish species (Taugbol and Skurdal, 1992;Celada et al 1993;Sáez-Royuela et al 1995, 2001Mazlum 2007) and experimental dry pellets for crayfish and crustaceans (Celada et al 1989;Savolainen et al 2004;Ulikowski et al 2006), have been used in feeding of crayfish juveniles.…”

Determining an effective density regime for rearing juvenileAustropotamobius pallipesin a small-scale closed system hatchery

“…These include Australian crayfish species (Cherax spp. ; Jones & Ruscoe, 2000;Naranjo-Páramo, Hernandez-Llamas, & Villarreal, 2004;Rodgers, Saoud, & Rouse, 2006); American red swamp crayfish (P. clarkii; Figiel & Miller, 1995;McClain, 1995); plus astacid species such as the signal crayfish (P. leniusculus; Ahvenharju, Savolainen, Tulonen, & Ruohonen, 2005;González et al, 2011a;Harlioğlu, 2009;Ulikowski, Krzywosz, & Śmietana, 2006), and noble crayfish (Astacus astacus, Linnaeus 1758), (Keller, 1988;Pursiainen, Jarvenpaa, & Westman, 1983).…”