Identifying Robust Proxies of Gonad Maturation for the Protandrous Hermaphrodite Tridacna maxima (Röding, 1798, Bivalvia) from Individual to Population Scale
|Author(s)||Menoud Mathilde1, 2, Van Wynsberge Simon1, 3, Le Moullac Gilles2, Levy Peva2, Andrefouet Serge, Remoissenet Georges4, Gaertner-Mazouni Nabila1|
|Affiliation(s)||1 : Univ Polynesie Francaise, Lab Excellence CORAIL, UMR EIO 241, BP 6570, Faaa, Tahiti, Fr Polynesia.
2 : IFREMER, Lab Excellence CORAIL, UMR EIO 241, BP 7004, Taravao 98719, Tahiti, Fr Polynesia.
3 : Univ Reunion, CNRS, Lab Excellence CORAIL, Inst Rech Dev,UMR ENTROPIE 9220, 101 Promenade Roger Laroque,BP A5, Noumea 98848, New Caledonia.
4 : Direct Ressources Marines & Minieres, Fare Ute, Immeuble Caill, BP 20, Papeete, Tahiti, Fr Polynesia.
|Source||Journal Of Shellfish Research (0730-8000) (Natl Shellfisheries Assoc), 2016-04 , Vol. 35 , N. 1 , P. 51-61|
|WOS© Times Cited||12|
|Keyword(s)||giant clam, marine bivalve, reproduction, spawn, Tatakoto atoll, histology, Tridacna maxima|
|Abstract||Monitoring gonadmaturation for protandrous and functional hermaphrodite species such as the giant clamTridacna maxima is difficult due to the juxtaposition and relative proportion ofmale and female tissues in the gonad [gonadal sex ratio (GSR)]. Here, the relevance of the widely used gonadosomatic index (GSI) as proxy of giant clam gonad maturation is tested with a large dataset (n = 265). Gonadosomatic index is compared with other indices, namely the proportion of the male part harboring spermatozoids, the proportion of empty oocyte follicles, the mean oocyte diameter, and the oocyte elongation. At gonad scale, high index variability highlighted partial spawning. At individual scale, male and female maturation proxies were contrasted, showing either asynchronous emissions of male and female gametes or contrasted spermatogenesis and oogenesis duration. The GSI was mostly driven by the number and diameter of oocytes and therefore it is recommended here as primary proxy for female maturity. Except for the oocyte elongation, all indices were affected by the GSR, which ruled out drawing conclusions at population scale. These results highlight the need for maturation stage proxies that are optimized for functional hermaphrodite species.|