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Recruitment of oysters in Mobile Bay. Sean Powers, Kyeong Park, C-K Kim, Jason Herrmann, and Ben LaCour. Fisheries Habitat Program. UNIVERSITY OF SOUTH ALABAMA DAUPHIN ISLAND SEA LAB. Alabama Oyster Fishery. Fisheries Habitat Program. 1,200,000. 1,000,000. 800,000. Landings (kg meat).
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Recruitment of oysters in Mobile Bay Sean Powers, Kyeong Park, C-K Kim, Jason Herrmann, and Ben LaCour Fisheries Habitat Program UNIVERSITY OF SOUTH ALABAMA DAUPHIN ISLAND SEA LAB
Alabama Oyster Fishery Fisheries Habitat Program 1,200,000 1,000,000 800,000 Landings (kg meat) 600,000 400,000 50 yr average 200,000 0 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Opal (3)& Erin (2) Ethel (3) Frederic (3) Elena (3) Camille (5)
Habitat Availability: Alabama Oyster Habitat (1972) Fisheries Habitat Program Live oyster reef Buried oyster shell deposits
Addressing Restoration Challenges Larval supply Dissolved Oxygen Predation 1 2 5 200 100 10 # spat m-2 d-1 (Hoese et al. 1972) Fisheries Habitat Program
Oyster Recruitment: 2006-2007 Survey 18 sites throughout Mobile Bay every three weeks for oyster settlement. Jan 2006 – Dec 2007 Synoptic measurements of larval supply via plankton pump samples. Discrete mark & recapture experiments for post-settlement mortality Validation of a 3-D bio-physical transport model. Fisheries Habitat Program
Spat Recruitment Methods Fisheries Habitat Program
Fisheries Habitat Program Predation: Oyster Drills
Comparison to Hoese et al. 1972 14 sites, same locations in 2006-07 Concrete tile, same as 2006-2007 Horizontal plate orientation 2-3 week deployments April-November Salinity and temperature ranges were similar Plates moored using fixed pilings
Hoese et al. 1972: Spatial Pattern 1 2 5 200 100 10 # spat m-2 d-1 (Hoese et al. 1972)
CR11 CR12 CR13 Spat/m2/day Larvae/1000L 30-100 μ Larvae/1000L 100-500 μ
CR14 CR15 CR16 Spat/m2/day Larvae/1000L 30-100 μ Larvae/1000 l 100-500 μ
Transport Transport Model
Post-settlement Mortality Mark & recapture experiments with newly settled larvae 7-11 mm SH set on concrete tiles by the Auburn Hatchery. Experiments conducted for 5-7 days. Middle Bay Miss. Sound Cedar Pt. Bon Secour Dauphin Island
Average by region Summer 2007 0.08 b 0.07 b b 0.06 0.05 Portion of Spat Mortality/Day ab 0.04 a 0.03 0.02 0.01 0 Bon Secour Cedar Point Dauphin Island Middle Bay Mississippi Sound
Implications for Restoration Further support for high success of reefs in western portion of the study area. Fisheries enhancement should focus attention in these areas. Possibility for spawning sanctuaries in Bon Secour Bay. High retention possible Low post-settlement mortality
Sanctuary positioning Results of the Park and Kim biophysical transport model indicating concentrations of dye released at Shellbank (upper panel) after 6 days and Fish River Reef after 10 days. Release location is indicated by the red star.
Acknowledgements Tech Support, boat time, fishing volunteers and graduate students