Early development of the postcranial skeleton of the pikeperch Sander lucioperca (Teleostei: Percidae) relating to developmental stages and growth.

The early development of the postcranial skeleton (pectoral girdle, pelvic girdle, vertebral column and fins) in pikeperch (Sander lucioperca (L.)) was studied from hatching to days 47 and 43 post fertilization (dpf) at two different rearing temperatures, 15.5 and 18.0°C. Four embryonic and six larval stages were described, ranging from 3.4 ± 0.3 mm to 21.8 ± 2.1 mm in total length. The crucial point in larval development is swimbladder inflation, which enables larvae to swim energy efficiently. Until this time point, only the most essential skeletal elements to enable swimming movements have developed. As the larvae become neutrally buoyant, they grow and differentiate postcranial elements rapidly. Concurrently, swimming performance and foraging success seems to improve. A specific size is correlated with a distinct developmental stage defined by a set of traits that includes the skeletal elements. The developmental sequence of skeletal structures is temperature independent, although growth is slower and the individual developmental stages are reached later at 15.5°C than at 18.0°C.