Biological movement increased larval retention near the spawning area, thus providing a favorable condition for local recruitment of oysters. A persistent gradient decreasing from west to east in the model results at time scales of overall average, season, and each survey in 2006 suggests that the larval supply may be responsible for the corresponding gradient in oyster spat settlement observed over the past 40 years. The model reasonably reproduced the observed gradient in oyster spat settlement and bivalve larval concentration, although the model results were less dynamic than the data, probably owing to the simplified biological conditions employed in the model. Site- and larval-specific conditions, including spawning location, spawning stock size, spawning time, and larval period, were determined based on the previous studies. A hydrodynamic model was used to simulate physical transport, and biological movement was parameterized as a function of swimming and sinking velocity of oyster larvae. A three-dimensional larval transport model accounting for physical transport, biological movement of larvae, and site- and larval-specific conditions was developed. Here we conducted a field and modeling study to investigate the larval transport of eastern oyster, Crassostrea virginica, in Mobile Bay and eastern Mississippi Sound, Alabama. The buoy is one of the first devices of its type in France, but after its first contact with this new technology, the shellfish farming sector is already thinking of measuring additional parameters, such as chlorophyll and pollutants.Among the various factors affecting recruitment of marine invertebrates and fish, larval transport may produce spatial and temporal patterns of abundance that are important determinants of management strategies. The Auray-Vannes FLAG played a key role by supporting the application for CLLD funding and coordinating the project partners. This would in turn lead to more efficient spat collection and increased oyster production. This would allow them to analyse the changes in the oyster’s natural environment and work out the best time to collect the spat. Hence, the Regional Shellfish Farming Committee of South Brittany submitted a project proposal to install a high-frequency multi-sensing buoy to gather data on these parameters. Studies carried out locally by the national marine research institute Ifremer linked environmental conditions, such as temperature and salinity, to oyster spawning, which directly impacts spat settlement quality and quantity. Oyster spawning is becoming less predictable, which is making it harder to collect spat for cultivation. The wild oyster stocks, the main source of spat for breeding this species in captivity, are increasingly threatened by climate change and human action, which worsen water quality and give rise to large temperature fluctuations. In France, the two main flat oyster collection areas are Brest Bay and Quiberon Bay, both in Brittany. This creates tiny larvae, which after 2-3 weeks grow legs and ‘settle’ by attaching themselves to a solid surface, where they are known as ‘spat’. Oysters breed by releasing their eggs and sperm into the water, where fertilisation takes place.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |