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Abstracts
Workgroup: Oyster Fisheries Management and Restoration
Oyster Harvest Efforts in Pre-Diversion Barataria Bay During a Decade of Salinity Shifts, 1990-99
Principal Investigator(s):
Earl J. Melancon, Jr., Biology Department, Nicholls State University, Thibodaux, LA, biol-em@nicholls.edu
Co-Investigator(s):
Eric Swenson, Louisiana State University; Peter Vujnovich, Jr., Captain Pete's Oyster Company, Port Sulfur, Louisiana.
Funding Period: 2001-03 (on-going)
We have delineated four oyster microhabitat areas in Barataria Bay based on summarizing commercial harvest records from an oyster vessel over the decade, 1990-99. As the bay's salinity habitat shifted during wet and dry climate periods, the oysterman correspondingly shifted his fishing efforts up and down bay to where oysters had set and survived to commercial size, generally „65mm in shell length. The microhabitat areas are being referenced against the 1990-99 semi-annual wet-dry climatic classification index for the bay system as developed by Swenson and Turner (1998); Detailed methods can be found in their publication. Semi-annual mean isohalines in 5-ppt increments are also being generated for the bay to correlate with fishing effort and the climatic classification index. We have also collected monthly oyster dredge samples during the period summer to fall 2002 to profile the oyster populations within each area and to correlate with prevailing salinity conditions in the bay; Oyster parameters measured were population size frequency distribution, condition index, gonad index, and sex ratio.
Area 1 is the most down-estuary, and highest salinity site, and preliminary results indicate a good correlation with wet-year estuary conditions which are conducive to oyster survival. Area 2 is adjacent to and up-estuary from area 1, and corresponds to habitat where some oysters survived regardless of wet or dry estuary conditions. Area 3 also has oysters to survive in wet-dry conditions, but is more up-estuary than Area 2. Area 4 is far up-estuary and conducive to oyster spat settlement and survival when salinities increase due to drought or near-drought conditions. Area productivity generally lagged one to three years behind salinity shifts that allowed for oysters to set, survive and grow to commercial size. The research is on going.
IMPACTS and/or BENEFITS:
The primary goal is to relate the pre-diversion natural shifts in commercial utilization of oyster leases within Barataria Bay to post-diversion shifts in salinity habitat. The ultimate goal is to investigate how habitat shifts affect an oysterman's ability to make a living and how wise utilization of diversions, within the context of wetlands management, may reduce negative fishery impacts.
PROJECT PUBLICATIONS:
No referred journal publications have yet been generated by this research.
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