Effects of climate change on pejerrey (Odontesthes bonariensis) reproduction.

MIRANDA, L.A., ELISIO, M., CHALDE, T.

Buenos Aires

Simposio; Satellite Symposium-7th International Symposium on Fish Endocrinology - 7ISFE; 2012

Comité Internacional

Analysis of the mean daily temperature in Pampas region (Chascomús county) over the last 45 years indicated an increase of 1.3º C. The aim of this research was to study how high water temperature impairs the reproductive activity of an emblematic fish from this region, the pejerrey Odontesthes bonariensis. Fish exposed at high water temperature fluctuation (over 23º C) during few days quit spawning, presenting clear signs of gonadal regression. At endocrine level, GnRH-I and FSH-β in both sexes, LH-β and GPH-α in males and FSH-R, LH-R and cyp19a1a in females decreased significantly in treated fish. Also, a strong reduction in plasma sex steroids levels was found for both sexes. In vitro assays demonstrated that ovary functions are directly disrupted by high water temperature independent of the brain-pituitary axis, being the inhibition of aromatase expression and consequently E2 synthesis a primary effect provoking female reproductive impairment. Temperature increase as consequence of global warming, coupled with the mechanisms of high-temperature sensitivity shown in this study, may be one of the reasons for the decline in pejerrey populations observed in this region over recent decades.