GSMFC Special Oyster Session: Louisiana. Patrick Banks Gulf States Marine Fisheries Commission Annual Meeting October 13, 2016

Transcription

1 GSMFC Special Oyster Session: Louisiana Patrick Banks Gulf States Marine Fisheries Commission Annual Meeting October 13, 2016

2 Current Status of Public Oyster Seed Grounds

3 Louisiana is #1 in U.S. Oyster Production Extensive Estuaries System of Public Oyster Areas and Private Leases Public Seed Grounds and Reservations: ~1.7 million acres Private Leases: ~400,000 acres

4 Public Seed Ground Management Activities: Goals: -Conserve/Promote wise utilization of oyster resource -Maintain/Improve seed and market oyster production Methods: -Biological Monitoring -Cultch Planting -Harvest Monitoring -Season Openings/Closures -Gear Regulations

5 Biological Monitoring: -Monthly Dredge Sampling -24 inch dredge -80 stations -two, 3 minute dredge tows per station -Goals: -Monitor recruitment, mortality, size frequency dist.

6 Biological Monitoring: -Annual Stock Assessment Sampling -Square meter sampling in July -107 stations -5 plots per station Oyster Stock Size = (density/m 2 ) x reef acreage

7 Biological Monitoring: Reef Mapping 2015:

8 Public Oyster Ground vs Private Lease Harvest Public harvest increased to 12% in 2016 from 5% in 2015

9 LA Oyster Management: Main Issues -Reef Improvement/Maintenance: Statewide -Most reefs degraded -Implementing Sustainable Oyster Shellstock Model -Political hurdles to conservative management -Changes in Hydrologic Regimes -Calcasieu Lake: increasing salinities/oyster drill predation -Breton Sound: decreasing salinities/no evidence of reproduction -Mississippi Sound Mortality Event: Several Interacting Factors -Late summer stressors: -Hypoxia -Elevated Dermo infection rates -Oyster Drill predation -Flood effects (decreased salinities for ~ 1 week) -Low energy reserves due to reproduction and summer stressors -Mortality Induced by Seasonal low-salinities -Barataria Bay, Vermilion Bay, Sabine Lake

10 LA Oyster Management: Main Issues Calcasieu Lake: Breton Sound: % seed -77.9% sack -27.7% total MS Sound Mortality: Seed: 83% Market: 94%

11 Deepwater Horizon NRDA Conclusions: -Primary impacts to Louisiana oyster populations: -Mortality and reproductive impairment of intertidal oyster populations through direct exposure -Mortality resulting from response (prolonged exposure to decreased salinities from freshwater diversions) Restoration Approaches: Currently Updating Strategic Oyster Plan Including: -Cultch Plants: proven large scale method of oyster restoration -Supplementing Natural Production with Hatchery Products -Remote Setting -Promoting Alternative Oyster Culture -Constructing Network of Spawning Stock Reefs -Locate using larval transport models: maximize cultch plants -Maintain reproduction during adverse hydrologic events -Appeals to multiple user groups -Additional Mapping of Oyster Resources Using Side-scan Sonar -Living Shorelines? Poor success for oysters in LA, expensive

12 Restoration Approaches: Remote Setting Process Broodstock Reef Network Concept Remote Setting Facility: Under Construction

13 Louisiana Hatchery Activities:

14 Potential for Oyster Aquaculture in Louisiana: -Currently any leaseholder can apply for an alternative oyster culture (AOC) permit. -Abundant area available: -Most private leases currently available -Review suitability maps (navigation/infrastructure) -Seasonal DHH closure areas Issues: -Still a new concept -Remoteness of oyster production areas (concern over theft) -Currently expanding AOC permit to include private waters -Will greatly expand potential aquaculture areas -Industry concern over spat availability -Few sources of spat/seed, hatchery production issues -Michael C. Voisin Oyster Hatchery main source -Currently LDWF only allow imports from: Auburn University Shellfish Lab, Dauphin Island, AL -LDWF concern over imports: -Florida: invasive green mussel (Perna viridis) -Eastern US: MSX disease

15 Future Oyster Fishery Threats -Political hurdles to sustainable oyster management -The answer can not always be more cultch -Need more conservative seasons to rebuild/maintain reefs -Primary Concern: Proposed Mississippi River Sediment Diversions -Part of State Coastal Master Plan (fight erosion, build land) -Much larger than existing diversions -Substantial Hydrologic Alteration to Major Oyster Production Areas -Operation plan must either: -minimize impacts to existing populations (pulses) -allow populations to shift down estuary -Concern inconsistent operation will drastically fluctuate optimal oyster production salinity zones QUESTIONS?