No Evidence for Intercohort Cannibalism in Mixed‐Size Cultures of Food‐Size and Fingerling Channel Catfish × Blue Catfish Hybrids Grown in Ponds

Abstract

Female Channel Catfish Ictalurus punctatus × male Blue Catfish I. furcatus hybrids are normally harvested by seining single-batch pond or split-pond production systems in fall or winter. Ponds are typically restocked with fingerlings without draining. There is concern that without completely draining the pond after harvest, food-size hybrids that escape seining may cannibalize restocked fingerlings. The purpose of this study was to determine if such hybrid fingerlings stocked after the fall harvest would be cannibalized by the larger carryover fish during winter or the following growing season. Three 0.04-ha ponds were each stocked on November 25, 2013, with 100 food-size hybrid catfish averaging 1.07 kg. Those three ponds and an additional three ponds were then stocked on November 27, 2013, with 300 hybrid catfish fingerlings averaging 14.8 g. The fish were not fed over winter. Mean survival of the fingerlings after 4 months at 91.9% and 92.9% was not significantly different between treatments. Survival of the food-size fish was 99.7%. Four ponds stocked with fingerling and food-size hybrids and an additional four ponds stocked with just fingerlings in April 2014 were harvested in October. Survival of the fingerlings was not significantly different between ponds with (88.8%) and without (90.3%) food-size fish. We found no significant intercohort cannibalism by food-size hybrid catfish on understocked fingerlings either overwinter or during the following growing season.

Effect of Grading Fingerling Hybrid Catfish (♀ Channel Catfish × ♂ Blue Catfish) on Growth, Production, Feed Conversion, and Food Fish Size Distribution

“…Survival averaged 90.0% overall (Table ); although survival was slightly higher in ponds stocked with graded fingerlings, it was not significantly different between treatments ( P = 0.11). Previous research with hybrid catfish has shown no evidence for intracohort cannibalism (Torrans and Ott ); therefore, we assumed that this difference was a random effect unrelated to treatment. The survival seen in this study was within the range of survival rates reported in other studies of hybrid catfish (Green et al.…”

Age Determination of Hybrid Catfish and Channel Catfish from Commercial Catfish Farms

“…(1999) reported numerous instances of cannibalism in tanks and ponds when fingerlings were stocked with larger Channel Catfish up to 374 g. There has been limited published research conducted on the foraging habits of hybrid catfish in commercial ponds due to their relatively new introduction to the catfish industry (Torrans and Ott 2016). A study conducted by Torrans and Ott (2016) stocked hybrid catfish fingerlings with market‐sized fish that were missed from the first production cycle and found no instances of cannibalism. Mortality rates were similar to fingerlings stocked in ponds without larger fish.…”

Split Ponds Effectively Overwinter Golden Shiners

“…To our knowledge, no overwinter studies have been published on hybrid catfish, ♀ Ictalurus punctatus × ♂ Ictalurus furcatus , in split ponds. Farmers attempt to harvest all hybrid catfish from these systems before the onset of winter (Torrans and Ott ). However, it is known that catfish in traditional ponds often lose weight overwinter, especially when not fed (Okwoche and Lovell ; Nanninga et al ).…”