EFFECT OF LIGHT INTENSITY AND MALE AND FEMALE EYESTALK ABLATION ON REPRODUCTION OF Penaeus stylirostris AND P. vannamei

Abstract

This 97‐day study, conducted during midwinter using a recirculating water system, was designed to evaluate the effect of light intensity and male and female eyestalk ablation on reproduction of P. vannamei and P. stylirostris. Four light intensities were established using various levels of fluorescent lighting (bright, 14.7 μEm‐2s‐1; moderate, 4.4 μEm‐2s‐1; dim, 0.6 μEm‐2s‐1; and dark, 0.0 μEm‐2s‐1) and the fifth consisted of artificial lighting supplemented with natural light through a translucent skylight (skylight, 4.7–9.3 μEm‐2s‐1). Unilateral eyestalk ablation was performed on all male P. vannamei in one of each pair of tanks within a treatment. In addition, half of the females in each tank were unilaterally ablated. Ovarian maturation, spawning, molting rate, and survival were monitored daily within each tank. Growth and gonad development were measured at termination. The optimum light intensity for P. stylirostris appeared to be lower than that for P. vannamei. P. stylirostris matured and spawned more frequently in the skylight and dim treatments than in the moderate, dark, and bright treatments. P. vannamei matured and spawned more frequently in the skylight, bright, and moderate treatments than in the dim and dark treatments. Natural light supplementation beneficially affected reproduction of both species. Male eyestalk ablation increased gonad size and doubled mating frequency of P. vannamei in comparison to unablated controls. This is the first documentation of increased penaeid shrimp reproduction by unilateral eyestalk ablation of males. Even more significant may be recognition that male gonadal development is a limiting factor in reproduction of shrimp in captivity.

Reproductive performance and offspring quality of non-ablated Pacific white shrimp (Litopenaeus vannamei) under intensive commercial scale conditions

“…vannamei have been assessed by Chamberlain and Lawrence (1981) and Palacios et al (1999b), and in other species (Santiago Jr, 1977;Emmerson, 1980;Chamberlain and Lawrence, 1981;Yano, 1984;Choy, 1987;Makinouchi and Primavera, 1987;Gendrop-Funes and Valenzuela-Espinoza, 1995). Zhang et al (1997) Lawrence 1981;Palacios et al 1999b). In addition, non-ablation did not have a significant effect on larval survival in zoea, mysis and postlarvae 1-day-old (PL1) stages (Palacios et al 1999b).…”

“…vannamei are based on the use of eyestalk ablation (Chamberlain and Lawrence, 1981;Zhang et al, 1997;Palacios et al, 1999a;FAO, 2003;Sainz-Hernández et al, 2008;Das et al, 2015). Eyestalk ablation involves the removal or constriction of one (unilateral) or two (bilateral) eyestalk through cutting, cauterizing or tying, to reduce the level of gonad inhibiting hormone (GIH) which is produced by the X-organ and sinus gland complex situated in the optic ganglia of the eyestalk (Alava and Primavera, 1979;Raviv et al, 2006;Bae et al, 2013;Treerattrakool et al, 2014).…”

Reproductive regulators in decapod crustaceans: an overview

“…For example, eyestalk removal in non-breeding adult males induces precocious spermatogenesis, and hypertrophy in the androgenic gland (Demeusy, 1953; Gomez and Nayar, 1965;Otsu, 1963). ESA of male white shrimp, L. vannamei, increased testicular size and doubled mating success (Chamberlain and Lawrence, 2009;Sreekumar and Adiyodi, 1983) suggested that ablation stimulates spermatogenesis and that inhibitory eyestalk principles (possibly GIH or MIH) play a role in the synchronized regulatory processes of reproduction and molting in Macrobrachium idella. Eyestalk removal in male Penaeus vannamei also enhanced the testicular index, spermatophore weight and total number of sperm but did not affect sperm viability (Leung-Trujillo and Lawrence, 2009).…”

Studies on Maturation, Spawning and Hatching Wild of Shrimp Penaeus monodon Fabrics, 1798 Collected from East Coast of India

“…When ablated females have been compared to non-ablated controls, the size of the spawns have been reported to be larger [34], smaller [8,35] and not different [35,36] or not different [36]. Hatch success has been reported to be lower or not different [8,34]. Some others reported deterioration in spawn quality from ablated females over time [21,35,37].…”