Induction of early spawning of channel catfish in heated earthen ponds

Document Type

Article

Publication Date

1-1-2003

Abstract

The spawning of channel catfish Ictalurus punctatus in earthen ponds is limited to the spring and early summer (late April through June) in North America, when water temperatures range from 24°C to 30°C. Temperature appears to be the primary factor that influences the timing of spawning in channel catfish. The heating of ponds will allow the spawning season to begin early. During the late winter and spring (February to early May) of 1997, 1999, 2000, and 2001, 0.03-ha earthen ponds containing male and female channel catfish broodstock (1.3—4.1 kg, 440680 mm total length) were heated at about 2°C/d by adding geothermally heated water (36°C) and then maintained within the range of 24-30°C. Four spawning containers were added to each pond and checked for eggs at 3-d intervals. Eggs were removed and evaluated for fertilization percentage. Over the 4 years, spawning in heated ponds occurred from 20 to 62 d in advance of spawning in unheated (control) ponds, and the period of egg production possible within one season was doubled. Spawning usually commenced within 1-2 weeks of the observation of nesting activity, and 2-4 weeks were required to collect a total of four masses (our criterion for the full onset of egg production in a heated pond). Fertilization was 87% ± 8% (mean ± SD) in spawns collected before the onset of spawning in unheated ponds (N = 67 masses) and 87% ± 5% in spawns collected during the normal season (N = 26 masses). There were no significant differences in the weight (P = 0.08) and fertilization percentage (P = 0.88) of egg masses collected early and during the normal spawning season. Problems encountered included disease outbreaks of Cleidodiscus sp., Ichthyophthirius multfilis, and Flexibacter columnaris in broodstock. Future studies should evaluate methods to reduce the added costs of heating ponds and incubating egg masses. © The American Fisheries Society 2003.

Publication Source (Journal or Book title)

North American Journal of Aquaculture

First Page

73

Last Page

81

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