The Influence of Sperm Activation Methods and Oocyte Collection on the Reproductive Effects of Northern Pike (Esox lucius)

This study compared the quality of northern pike eggs collected using traditional methods (hand stripping) and pneumatic methods (air stripping). The effects of different activation solutions (0.4% NaCl, 0.8% NaCl, and hatchery water) on egg fertilization under controlled conditions were also investigated. After egg collection, the Pseudo-Gonado-Somatic Index (PGSI) was measured; the PGSI values in the samples obtained using the pneumatic method (13.8 ± 3.9%) were lower, but did not differ statistically from those obtained by hand stripping (16.5 ± 5.4%). The 0.4% NaCl solution proved to be the most effective for sperm activation, as assessed by the Computer-Assisted Sperm Analysis (CASA) system, compared to the 0.8% NaCl solution. The pneumatic method achieved a higher egg collection efficiency (93.7% occlusion) than the traditional method, with significant differences observed in groups activated with water. The average hatching percentage of larvae was 89.5% in groups using the pneumatic method, compared to 71.2% in the traditional groups, highlighting the advantages of this modern approach. The application of the pneumatic method and 0.4% NaCl for the artificial fertilization of northern pike resulted in higher fertilization and hatching rates compared to other techniques, making this method a promising option for the artificial reproduction of other fish species.