Studies on the captive breeding of the Knysna seahorse, Hippocampus capensis
Authors: Lockyear, J.; Kaiser, H.; Hecht, T.
Source: Aquarium Sciences and Conservation, Volume 1, Number 2, 1997 , pp. 129-136(8)
Abstract:Seahorse populations throughout the world are vulnerable to exploitation for use in traditional Chinese medicines. Various captive breeding ventures have been established in attempts to meet the demand and to reduce the pressure on the natural populations. Many of these programmes have relied on the capture of wild pregnant males which then give birth under captive conditions. This would however limit production during the non- breeding season. In this study Knysna seahorses, Hippocampus capensis, were bred in captivity during the non-breeding season (winter) using photothermal manipulation. Three constant photoperiods (20L:4D, 16L:8D & 12L:12D) were tested in combination with three temperatures (22 °C, 25 °C & 28 °C). All combinations tested were successful in extending the breeding season of H. capensis. The frequency of pregnancies as well as the number of young produced/pregnancy was not affected by the different photoperiod/temperature combinations. Each male gave birth to 39.38 ± 20.81 juveniles every 34.03 ± 17.25 days during a four month period. The mean juvenile weight and length was influenced by the photoperiod and/or temperature regimes. Juvenile length decreased with increasing temperature (p ≤ 0.0001), while an increase in the light phase of the photoperiod regime at 20L:4D resulted in a significant increase (p ≤ 0.0006) in length when compared to the 16L:8D and 12L:12D photoperiods. Juvenile weight decreased with increasing temperature, while the combination of photoperiod 16L:8D and the lowest water temperature (22 °C) yielded the highest mean weights. Further studies are necessary to determine whether mean juvenile weight or length influences juvenile survival
Document Type: Regular Paper
Affiliations: Department of Ichthyology and Fisheries Science, Rhodes University, PO Box 94, Grahamstown, 6140 South Africa
Publication date: January 1, 1997