Impact of temperature and rainfall alterations on the spawning behavior of Indian major carps and consequence on fishers income in Odisha

Abstract

The present communication assessed the impact of the changes in climatic variables, viz . temperature and rainfall onthe spawning of Indian Major Carps (IMC) in the river Mahanadi, in the fish hatcheries in its plains and on the fishers’income in five districts of Odisha. The average minimum and maximum temperature throughout the state has increasedin the range of 0.1 °C to 0.9 ºC. The annual rainfall in Cuttack and Puri districts have increased by 27.78 mm and 13.20mm respectively and decreased by 18.73 mm, 16.25 mm, 7.4 mm, 86.88 mm and 11.25 mm in Angul, Balasore, Khurda,Sambalpur and Bolangir districts, respectively during 1981-2010. The fish spawn availability has decreased drasticallyin river Mahanadi in three decades from 30-43 ml net -1 day -1 to the present level of 6 ml net -1 day -1 . The study revealedthat the onset of the breeding period of the Indian major carps has advanced by one month in the hatcheries, comparedto the previous two decades. The advancement in breeding period of IMC in the fish seed hatcheries in Balasore,Khordha, Puri and Mayurbhanj districts can be attributed primarily to the effect of increased water temperature andshifting of the rainfall pattern facilitating early maturation and spawning. The respondents in the fish seed hatcheriessurveyed also perceived temperature and rainfall as the most important factors responsible for advancement of theonset of breeding of IMC.