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1 April 2013 Patterns of Egg Deposition and Egg Development in the Catsharks Poroderma pantherinum and Haploblepharus pictus
C. Pretorius, C.L. Griffiths
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Abstract

Patterns of egg deposition and rates of egg development were examined for two endemic South African scyliorhinid shark species: Poroderma pantherinum, the leopard catshark, and Haploblepharus pictus, the dark shy shark. P. pantherinum laid their eggs at an average depth of 18.95 m (min: 7.4 m; max: : 26.8 m) preferentially attaching their eggs singly onto sea fans Leptogorgia palma, Eunicella papillosa and Eunicella tricoronata. H. pictus laid their eggs at an average depth 3 m (min: 1 m; max: 30.7 m) and attached their eggs, predominantly in pairs, to the seaweed Bifurcariopis capensis. The average temperature at which eggs were found were similar (15°C) and eggs were laid year-round. Embryo development was observed in the laboratory under constant controlled environmental conditions of 14 and 17°C. Embryo length-age relationships were linear for both species and there were significant differences in growth rate at the two temperatures. For P. pantherinum average growth rate was 0.37 mm/day at 14°C and 0.79 mm/day at 17°C. The average incubation period was 266 days at 14°C and 125 days at 17°C. Embryos thus grew two times faster and development time was 53% shorter when the temperature was raised by only 3°C. For H. pictus, the average growth rate was 0.49 mm/day at 14°C and 0.78 mm/day at 17°C. The incubation period was 242 days at 14°C and 190 days at 17°C. The embryos thus grew 1.6 times faster and incubation time was 21.5% shorter when temperature was raised by only 3°C.

C. Pretorius and C.L. Griffiths "Patterns of Egg Deposition and Egg Development in the Catsharks Poroderma pantherinum and Haploblepharus pictus," African Zoology 48(1), 115-124, (1 April 2013). https://doi.org/10.3377/004.048.0114
Received: 12 January 2013; Accepted: 1 April 2013; Published: 1 April 2013
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