Controlling gonad maturation on snakehead (Channa striata, Bloch 1793) for eliminating impact of climate change

Abstract

The consequences of climate change, in general, are changes in temperature and extreme season. Related to the fish gonad maturation, the effect of temperature can be distinguished by its effect on fish depending on the pattern of the reproduction and spawning season. In fish that spawn seasonally, rising temperatures in the tropical area signal the fish to ripen the gonads and migrate to the spawning area for ovulation in the early spawning season. Therefore, changing in the beginning and its duration of the season related to climate change will affect the maturity of fish gonads. In this paper communication, controlling gonad maturation on snakehead for eliminating impact of climate change is discussed. Observation of the gonad development on thirty mature snakehead stocks in Bogor, West Java, was conducted every month during a year. The obtained data were then compared to a similar previous study in the same area to have better insight on the impact of climate change on gonad development. To eliminate natural signal influence on the snakehead spawning, the study of gonad maturation in spawning (August to January) and out spawning season (February to July) using combination hormone of Pregnant Mare Serum Gonad (PMSG) and Anti Dopamine (AD) was done. The study used three breeders for each season, the dosage hormone of 2 mL/kg body weight was injected every month when the eggs were starting to develop, from September to November for spawning season and from May to July for out spawning season. The observed parameters were eggs diameter, fecundity, estradiol concentration, and gonadosomatic index. The results showed that reproductive performance tends to decline and fluctuate compared to the previous study done two years earlier. The highest eggs diameter, fecundity, and gonadosomatic index were in November. Hormone treatments in spawning and out spawning season were not significantly different (P>0.05) in the eggs diameter. The concentration of estradiol in the spawning season were higher than out spawning season, but they were not significantly different (P>0.05). Thus, hormone induction out the spawning season enabled to enhance breeder maturation as in the spawning season. Based on the result, hormone treatment could be used as an alternative to control maturation on the snakehead breeders from the impact of climate change.