Consulta: subjectFacets:"Tridacna maxima"
Registros recuperados: 3
Data/hora: 06/06/2024 17:22:53

Understanding consequences of adaptive monitoring protocols on data consistency: application to the monitoring of giant clam densities impacted by massive mortalities in Tuamotu atolls, French Polynesia
Provedor de dados: 5
Autores: Georget, Stephane; Van Wynsberge, Simon; Andrefouet, Serge.
During long-term monitoring, protocols suitable in the initial context may have to change afterward because of unforeseen events. The outcome for management can be important if the consequences of changing protocols are not understood. In Tuamotu Archipelago atolls, French Polynesia, the density of giant clams (Tridacna maxima) has been monitored for 12years, but massive mortalities and collapsing densities forced to shift from a line-intercept transects and quadrats (LIT-Q) method to a belt-transect (BT) method. We investigated with a simulation approach the conditions (density, size structure, aggregation of giant clam populations) under which the two methods provided different results. A statistical model relating the BT density to the LIT-Q density was...
Tipo: Text
Palavras-chave: Belt-transect; Ecological monitoring; Fishery; Line-intersect transects; Mass mortality; Quadrats; Sampling methods; Time series; Tridacna maxima.
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00516/62717/69556.pdf

Identifying Robust Proxies of Gonad Maturation for the Protandrous Hermaphrodite     Tridacna maxima     (Röding, 1798, Bivalvia) from Individual to Population Scale
Provedor de dados: 5
Autores: Menoud, Mathilde; Van Wynsberge, Simon; Le Moullac, Gilles; Levy, Peva; Andrefouet, Serge; Remoissenet, Georges; Gaertner-mazouni, Nabila.
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...
Tipo: Text
Palavras-chave: Giant clam; Marine bivalve; Reproduction; Spawn; Tatakoto atoll; Histology; Tridacna maxima.
Ano: 2016
URL: http://archimer.ifremer.fr/doc/00333/44441/44111.pdf

Changes in fatty acid composition in the giant clam Tridacna maxima in response to thermal stress
Provedor de dados: 5
Autores: Dubousquet, Vaimiti; Gros, Emmanuelle; Berteaux-lecellier, Veronique; Viguier, Bruno; Raharivelomanana, Phila; Bertrand, Cédric; Lecellier, Gael J.
Temperature can modify membrane fluidity and thus affects cellular functions and physiological activities. This study examines lipid remodelling in the marine symbiotic organism, Tridacna maxima, during a time series of induced thermal stress, with an emphasis on the morphology of their symbiont Symbiodinium. First, we show that the French Polynesian giant clams harbour an important proportion of saturated fatty acids (SFA), which reflects their tropical location. Second, in contrast to most marine organisms, the total lipid content in giant clams remained constant under stress, though some changes in their composition were shown. Third, the stress-induced changes in fatty acid (FA) diversity were accompanied by an upregulation of genes involved in lipids...
Tipo: Text
Palavras-chave: Thermal stress; Fatty acids; Differential expression; Antioxidant; Symbiodinium; Tridacna maxima.
Ano: 2016
URL: https://archimer.ifremer.fr/doc/00361/47195/79514.pdf