Acta Ichthyologica et Piscatoria 36(2): 105-112, doi: 10.3750/AIP2006.36.2.03
Grow-out of northern pike (Esox lucius L.) larvae under uncontrolled conditions
expand article infoB. Wolska-Neja, Z. Neja
Open Access
Background. This study aimed to determine survival rate, extent of cannibalism, and growth rate of northern pike (Esox lucius L.) larvae fed live zooplankton during a grow-out period, i.e., the time prior to when fish become valuable as stocking material. An attempt was also made to assess the food conversion ratio (FCR) with respect to the natural food applied. Materials and methods. Grow-out operations began with 1-day-old pike larvae and involved experimental in-ground tanks with no artificial aeration, forced water flow, artificial circadian lighting, or temperature control. Differently structured habitats (black polyethylene foil, vascular plants, or plastic netting) were placed in all the tanks to separate larvae and provide cover. Feeding live zooplankton to the larvae began on day 3 and food was administered such that larvae were always surrounded by a zooplankton "cloud." Results. The survival rate during the first- (days 1-7) and second (days 8-27) stage of culture was 92.3% and 95.7%, respectively. Highest survival rates were associated with tanks with polyethylene foil habitats, while lowest survival rates were associated with tanks containing plastic netting. No cannibalism was observed in any tank. During the growout period, the total length of larvae increased by an average of 20.88 mm. Although the length increase observed in the three experimental treatments was similar; the significantly highest (P
fish, pike, Esox lucius, larvae, larval grow-out, crustacean diet