caa a22 4500 606226761 CHVBK 20210128101154.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s10641-014-0231-1 doi (NATIONALLICENCE)springer-10.1007/s10641-014-0231-1 Reproductive traits of the western Pacific gizzard shad Nematalosa come [Elektronische Daten] implications for conservation and management in a population at its distributional margin [Masato Uehara, Katsunori Tachihara] Accurate descriptions of reproductive profiles are important for effective conservation and stock assessment efforts. We examined the reproductive traits of an Okinawan population of western Pacific gizzard shad (Nematalosa come) using histological analyses. The observed lengths at 50% maturity were approximately 180mm standard length (SL) for females and 130mm SL for males, which corresponded to 4-year-old fish for females and at least 2-year-old fish for males. The spawning season was estimated to occur from January to August, peaking from March to June, with active spawning occurring during an increase in seawater temperature. The lipidosomatic index of both sexes decreased until June, presumably as the fish expended energy to spawn. The fecundity (F) of females, tested using 62 ovaries, was related to SL: F = 3.471 × 10−2 × SL3.122. The Okinawan population of N. come had a longer spawning season and a higher fecundity than other populations for which these data are available. Such favorable traits may contribute to the persistence of this population at the species' distributional margin. Our findings indicate that the spawning seasons of Okinawan populations of N. come and Nematalosa japonica overlapped, implying that hybrid production occurs under natural conditions. Around Okinawa Island, however, the extent of shallow waters is rapidly decreasing because of recent land reclamation. We suggest the diminution of suitable sites as a possible factor for narrowing spawning opportunities and promoting the recent appearance of natural hybrids. Shallow habitats should be conserved to preserve healthy populations of the species. Springer Science+Business Media Dordrecht, 2014 Gizzard shad nationallicence Sexual maturity nationallicence Reproductive cycle nationallicence Distributional margin population nationallicence Uehara Masato Graduate school of Engineering and Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, 903-0213, Nakagami-gun, Okinawa, Japan aut Tachihara Katsunori Laboratory of Fisheries Biology and Coral Reef Studies, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, 903-0213, Nakagami-gun, Okinawa, Japan aut Environmental Biology of Fishes Springer Netherlands 98/1(2015-01-01), 1-10 0378-1909 98:1<1 2015 98 10641 https://doi.org/10.1007/s10641-014-0231-1 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10641-014-0231-1 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Uehara Masato Graduate school of Engineering and Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, 903-0213, Nakagami-gun, Okinawa, Japan aut NATIONALLICENCE 700 1- Tachihara Katsunori Laboratory of Fisheries Biology and Coral Reef Studies, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara-cho, 903-0213, Nakagami-gun, Okinawa, Japan aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Springer Netherlands 98/1(2015-01-01), 1-10 0378-1909 98:1<1 2015 98 10641