The population biology of pike, Esox lucius L., in two gravel pit lakes, with special reference to early life history.

Abstract

The population biology of pike in two gravel pit lakes of contrasting habitat type were studied. The density of pike (I+ and over) in November 1987 in the Main Lake was 7.7 fish ha^-1 (19 kg ha^-1) and in St Peter's was 71 fish ha^-1 (53 kg ha^-1). The age distribution showed that recruitment was consistent in St Peter's but variable in the Main Lake. The main factor causing this difference in recruitment is abundance of aquatic vegetation. Survival up to November 1987 of 0-group pike in the Main Lake was 0.00175% from potential egg deposition, producing 6.6 fish ha^-1 (0.83 kg ha^-1). In St Peter's survival was 0.00315%, producing 23 fish ha^-1 (3.04 kg ha^-1).