Low temperature exposure to post-vitellogenic channel catfish, Ictalurus punctatus extend reporductive readiness

Authors: Chatakondi, Nagaraj

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/2013
Publication Date: 2/9/2014
Citation: Chatakondi, N.G. 2014. Low temperature exposure to post-vitellogenic channel catfish, Ictalurus punctatus extend reporductive readiness. Aquaculture America Conference. P.70.

Interpretive Summary:

Technical Abstract: Channel catfish, Ictalurus punctatus.spawn annually during the spring and early summer (24 -30 °C). Environmental temperature is the main factor that controls the seasonal maturation of gonads and the timing of spawning. Temperature fluctuations can adversely affect spawning and broodfish condition, and cause spawning to cease or altered. Hormone-induced spawning of channel catfish to produce channel x blue hybrid catfish is presently practiced during the spawning season. However, paucity of gravid females during the later stages of the spawning season is a limitation. Past studies have advanced the spawning time of Atlantic salmon and Rainbow trout by temperature manipulations. Hence, the present study is based on the hypothesis that exposing vitellogenic channel catfish broodstock to cooler temperatures would condition them to extend reproductive readiness toward the end of the spawning season. Three-year old Delta strain of Channel catfish were hand selected and held in six 0.01 ha ponds. Replicated ponds were exposed to cooler waters (3 – 5 ° cooler than pond temperature) for 0, 10 and 20 days during mid-March, which coincides with the post-vitellogenic period in catfish. Normal broodfish husbandry practices were practiced in all the ponds. All the fish in a pond were seined at monthly intervals and individual fish was ranked based on secondary sexual characteristics and its potential to ovulate. Post-vitellogenic females exposed to 10 days of cooler water resulted in higher (P< 0.05) proportion of gravid females in June (extended period) compared to 0 and 20 exposure periods (Figure 1). Reproductive performance of gravid females from the three exposure periods were induced spawned at monthly intervals and compared. Research results will be discussed and implications of the findings to hybrid catfish fry production will be presented.