Authors: MEVLÜT AKTAŞ, METİN KUMLU
Abstract: The effects of eyestalk ablation on maturation, moulting and spawning in Penaeus semisulcatus were investigated in this study. Twelve males and 12 eyestalk-ablated and 12 non-ablated, all individually marked females were stocked into a 12-ton maturation tank. All the ablated females moulted in 9.08±1.68 days and first spawning occurred 16.75±3.41 days following eyestalk ablation. While all the ablated females spawned, producing an average of 177.000 ±133.340 eggs, only three non-ablated females spawned, producing average of 23.216±16.957 eggs during a period of 45 days (P<0.05). Throughout the experiment, the average number of spawnings per female was 3.17±1.40 for ablated and 1 for non-ablated ones. Multiple spawning (up to four times) occurred within the same moulting cycle in ablated females. Irrespective of the ablation treatment, the average fertility rate of the eggs was high, ranging between 84 and 87% (P>0.05). Average nauplii production per female was 81.574±55.126 for ablated and 13.397±11.535 for non-ablated ones (P<0.05). This study demonstrates that eyestalk ablation is necessary to induce maturation and spawning of P. semisulcatus in captivity. By eyestalk ablation and management of environmental conditions, it should be possible to obtain seeds for shrimp farms to head-start on-growing in the early spring under the subtropical conditions of Turkiye.
Keywords: Penaeus semisulcatus, maturation, spawning, moulting, broodstock
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