caa a22 4500 477116817 CHVBK 20180405111624.0 cr unu---uuuuu 170330e19961001xx s 000 0 eng 10.1007/BF00005037 doi (NATIONALLICENCE)springer-10.1007/BF00005037 Temperature effects on sex differentiation of two South American atherinids, Odontesthes argentinensis and Patagonina hatcheri [Elektronische Daten] [Carlos Strüssmann, Josue Calsina Cota, Germano Phonlor, Hiroyuki Higuchi, Fumio Takashima] Synopsis: The present study investigated the effects of water temperature (18, 21, and 25 °C) on the histological process of gonadal sex differentiation of two commercially important atherinid fishes from South America, Odontesthes argentinensis (sea pejerrey) and Patagonina hatcheri (Patagonian freshwater pejerrey). In both species, female gonadal sex differentiation began with the formation of lateral stromal cell outgrowths and the appearance of meiotic oocytes. The male gonads remained quiescent for about twice as long as the female gonads, with differentiation becoming evident by the formation of the main sperm duct and of cysts of germ cells at the periphery of the gonads. Meiosis in males occurred relatively long after somatic differentiation of the testis. The ovaries of O. argentinensis differentiated at 28 days (20.3 mm) at 25 °C, 42 days (24.0 mm) at 21 °C, and 56 days (23.8 mm) at 18 °C. In the males, differentiation was observed at 98 days at 25 and 21 °C (39.4 mm and 40.4 mm, respectively), but at 112 days under 18 °C (40.7 mm). In P. hatcheri, differentiation of females occurred at 21 days (17.8 mm) at 25 °C, 28 days (20.8 mm) at 21 °C, and 35 days (23.2 mm) at 18 °C. Male differentiation became evident at 56 days under 25 and 21 °C (30.8 and 32.7 mm, respectively), and at 70 days (37.7 mm) at 18 °C. The sex-ratios of O. argentinensis reared at 18 or 21 °C were female-biased whereas those at 25 °C were not; groups reared at 18 °C had significantly more females than groups from the same progeny reared at 25 °C. In contrast, the sex-ratios in all groups of P. hatcheri did not differ significantly from 1:1 and no significant differences were found between groups of the same progeny reared at different temperatures. These results suggest the occurrence of thermolabile sex determination (TSD) in O. argentinensis whereas in P. hatcheri gonadal sex appears to be strongly genetically determined. Kluwer Academic Publishers, 1996 Sex determination nationallicence ESD nationallicence TSD nationallicence Pejerrey nationallicence Fishes nationallicence Gonads nationallicence Histology nationallicence Strüssmann Carlos Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut Calsina Cota Josue Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut Phonlor Germano Department of Oceanography, Rio Grande University, Rio Grande, RS, Brazil aut Higuchi Hiroyuki Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut Takashima Fumio Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl 47/2(1996-10-01), 143-154 0378-1909 47:2<143 1996 47 10641 https://doi.org/10.1007/BF00005037 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00005037 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Strüssmann Carlos Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut NATIONALLICENCE 700 1- Calsina Cota Josue Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut NATIONALLICENCE 700 1- Phonlor Germano Department of Oceanography, Rio Grande University, Rio Grande, RS, Brazil aut NATIONALLICENCE 700 1- Higuchi Hiroyuki Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut NATIONALLICENCE 700 1- Takashima Fumio Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato, 108, Tokyo, Japan aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl/ 47/2(1996-10-01), 143-154 0378-1909 47:2<143 1996 47 10641 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer