Short-term storage of ova of common carp and tench in extenders

In a study of the effect of short-term storage on the hatching rate of comm on carp Cyprinus carpio and tench Tinca tinca ova in vitro in various exten ders at 21 degreesC under aerobic conditions, the best extender for 30 min storage for common carp appeared to be Dettlaff 1. This gave the same hatch ing rate, as controls without extender (55% v. 56%). For 60 min storage of ova, the best extenders were Dettlaff 2 (24% hatching rate) and Dettlaff 3 (30%), but hatching was significantly lower than in the control (58%). In c arp ovarian artificial fluid (CAF) extender, the hatching rate of common ca rp ova was also high after 10 min, but decreased to 12% after 30 min. In te nch, the hatching rate of ova increased after 10 min storage in Dettlaff 5 extender (44%) compared to the control (41%) without extender. However, it was significantly lower after storage in Dettlaff 1, 2, 3, 4, 5 and CAF ext enders for 20, 30 and 60 min, compared to controls. Malformations (10-50%) were observed in the tench second control groups without extender after 10, 20 and 30 min storage of ova. (C) 2001 The Fisheries Society of the Britis h Isles.