Some aspects of the reproductive biology of albacore Thunnus alalunga from the western Mediterranean Sea
Saber, S.; Ortiz de Urbina, J.; Gómez-Vives, M.J.; Macías, D. (2015). Some aspects of the reproductive biology of albacore Thunnus alalunga from the western Mediterranean Sea. J. Mar. Biol. Ass. U.K. 95(8): 1705-1715. https://dx.doi.org/10.1017/S002531541500020X In: Journal of the Marine Biological Association of the United Kingdom. Cambridge University Press/Marine Biological Association of the United Kingdom: Cambridge. ISSN 0025-3154; e-ISSN 1469-7769, more Also appears in:Sukhotin, A.; Frost, M.; Hummel, H. (Ed.) (2015). Proceedings of the 49th European Marine Biology Symposium September 8-12, 2014, St. Petersburg, Russia. European Marine Biology Symposia, 49. Journal of the Marine Biological Association of the United Kingdom, 95(8). 1517-1721 pp., more |  |
| Keyword | | | Author keywords | Size distribution, sex ratio, gonadosomatic index, histology, sexual maturity, spawning season |
| Authors | | Top | - Saber, S.
- Ortiz de Urbina, J.
- Gómez-Vives, M.J.
- Macías, D.
| | |
| Abstract | Thunnus alalunga is an important commercial tuna species widely distributed in the three major oceans and the Mediterranean Sea. The Mediterranean population is currently classified as a data-poor stock and little is known about its basic life history parameters. This study provides the first detailed information on some aspects of the reproductive biology of T. alalunga from the western Mediterranean Sea. A total of 16 104 specimens were measured between 2005 and 2012. The overall sex ratio of females to males was 1.1:1, although the ratio was female biased in fish <70 cm fork length (L F ) and male biased in those >75 cm L F . Histological analysis of the ovaries (N = 587) and the monthly variation of the gonadosomatic index for both sexes showed that spawning occurred from June to August, which is a much shorter period than the 7 months reported for T. alalunga in tropical oceanic waters. Thunnus alalunga caught during June and July are capable of spawning daily. The gonadosomatic index values for T. alalunga from the western Mediterranean were up to eight times higher than those of T. alalunga from other oceans. Histological examination of the ovaries showed that the minimum length at sexual maturity of females was 56 cm LF, which is considerably smaller than those estimated for other stocks. |
|
