Sustainable Fishery Sustainable Habitat Managing Oysters in Delaware Bay David Bushek, Kathy Alcox & Lisa Calvo
Philadelphia Baltimore Wilmington HSRL Delaware Bay is (geographically) DC Delaware Bay superior to Chesapeake Bay Chesapeake Bay Atlantic Ocean
Celebrating 10 years Provides students with authentic research and restoration experience in the Delaware Bay o o o o o o Community-based oyster restoration In-school enrichment Field trips Curriculum Guides Teacher workshops Stewardship opportunities for all ages
Intensive Oyster Aquaculture Photo: B Hollinger Small, but large potential, many challenges: - Regulatory - User conflicts - Endangered species Report: hsrl.rutgers.edu
Benefits of a sustainable harvest: Restoration does not create a sustainable harvest, but creating a sustainable harvest provides ecological restoration
Fishing vs Farming According to FAO/USDA/NOAA/NJ DEP: Aquaculture is understood to mean the farming of aquatic organisms including fish, molluscs, crustaceans and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, protection from predators, etc. Farming also implies individual or corporate ownership of the stock being cultivated.
The Fishery Aquaculture gradient Open Fishery Extensive Aquaculture Semi-intense Aquaculture Intensive Aquaculture Low Intensity Care Low Production Costs High Intensity Care High Production Costs Examples: Salmon fishing salmon ranching salmon pens Catfishing stocking lake/river catfish ponds Shrimping capturing PL s spawn & rear Oystering plant shell/seed rack & bag culture Collect seaweed removing grazers catch spores for raceways
Delaware Bay Oyster Landings 3.5 Millions of bushels 3 2.5 2 1.5 1 0.5 0 1880 1890 1900 1910 1920 1930 1940 Time 1950 1960 1970 1980 1990 2000 2010 2020
Delaware Bay Oyster Landings Millions of bushels 3.5 3 2.5 2 1.5 1 0.5 0 Statewide 1880 1890 1900 1910 1920 1930 Delaware Bay MSX 1940 1950 1960 1970 1980 DERMO 1990 2000 2010 2020 Disease major factor in limiting harvest Landings at 1% historic harvest Landings Population Not all bushels are equal Population roughly ~15% of maximum levels we can confidently estimate, which we believe are close to carrying capacity Fishery has adapted and evolved to remain sustainable MSX = Haplosporidium nelsoni Dermo = Perkinsus marinus
Population controlled by survival/disease Fishing controlled by us 36 Live Oysters % Oyster Death 100% 32 90% Number of Oysters (billions) 28 24 20 16 12 8 4 Major MSX outbreak MSX invasion Low MSX Dermo 80% 70% 60% 50% 40% 30% 20% 10% Oyster Percent Dead 0 0% 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 Year 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 Throughout this period, Delaware Bay oyster fishery has been sustainably managed
Delaware Bay Oyster Population 10ppt Oysters exist throughout Bay with highest abundance in upper bay natural or seed beds Additional oysters exist in tributaries and marshes Closed waters = natural sanctuaries Oyster recruitment, growth, condition and quality all increase with salinity 28ppt Oyster predation & mortality increase with salinity
Traditional Bay Season Fishery 10ppt Oyster recruitment, growth, condition and quality all increase with salinity Bay divided into natural beds and planted grounds Oysters transplanted during bay season for cultivation on leased grounds 28ppt Additional oysters imported from out of state to increase production
Different Management Different Landings Bay Season Direct Market
Long-term data highlight role of disease 1x10 +11 Abundance 100% Mortality Oyster Abundance (log scale) 1x10 +10 1x10 +9 80% 60% 40% 20% Percent Natural Mortality 1x10 +8 0% 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 MSX High MSX Low MSX Dermo onset -- adjustment Oyster abundance in Delaware Bay is inversely related to mortality, which is largely controlled by disease.
Long-term data indicate population change in not linked to fishing Oyster Abundance (log scale) 1x10 +11 1x10 +10 1x10 +9 Abundance Fishing 100% 80% 60% 40% 20% 1x10 +8 0% 1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 2007 2009 2011 2013 Percent Fishing
Mortality as Fraction of Oyster Stock 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 Fishing mortality (aka exploitation) has been a small fraction of total annual mortality. Less than 2% Natural 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 Exploitation High mortality rates, driven up by persistent disease pressure requires precautionary fishing rates other fisheries often operate at 10, 15 or 20%.
Delaware Bay Oyster Resource Management New Jersey DEP Haskin Shellfish Research Lab NJ Oyster Industry & Shellfish Council
Key Management Strategies: 40% Rule harvest control point (biological reference pt) Area Management spreads harvest Quantitative Survey key component Abundance Based Quota closely controls harvest Direct Marketing avoids lower bay losses to predation, disease and fouling
18 th Annual New Jersey Delaware Bay Oyster Stock Assessment Haskin Shellfish Research Laboratory February 9-11, 2016
New Jersey s annual oyster stock assessment is a formal, peer-reviewed, cooperatively managed process. The Haskin Shellfish Research Lab monitors oysters throughout the year culminating in a spatially explicit population assessment each fall. Survey and other program results are presented at a Stock Assessment Workshop (SAW) and are evaluated by a Stock Assessment Review Committee (SARC) The SARC has 9 rotating positions that include academicians, resource managers, and industry members from New Jersey and elsewhere.
Group Members Duties NJDEP Biologists Managers Statisticians Enforcement Administrators Approves all decisions impacting public oyster resource. Lead/coordinate management activities. Monitor harvest/enforce regulations. Collect, maintain & disperse industry imposed harvest taxes. Rutgers Haskin Shellfish Research Laboratory (HSRL) HSRL faculty and staff Design & analyze stock assessment. Execute surveys with industry and NJDEP assistance. Address science needs. Host and facilitate SAW. Prepare SAW report. Shellfish Council Industry Select harvest rate & area mgmt. activities from SARC recommendations. Plan and approve disbursement of industry imposed harvest taxes. Oyster Industry Science Steering Commiqee HSRL Shellfish Council NJDEP Prioritize science agenda and management strategies. Nominate SARC membership Stock Assessment Review Commi<ee (SARC) Academics: 1 RU + 2 external. Managers: 2 NJ + 2 external. Industry: 1 Council + 1 Peer review of assessment. Recommend harvest rates & area management by region. Provide science advice
Stock Assessment Design Resurvey: Update/Re-Map the Distribution of Oysters Stock Assessment Survey: Quantify the Number of Oysters in Each Region Review Other Relevant Regional Metrics: Mortality, Disease, Recruitment, Shell Budget, Fishery Statistics Ask SARC to Evaluate: 1.) Abundance Relative to Reference Points 2.) Stoplight Diagram of Regional Metrics Calculate Error: Estimate Uncertainty in Regional Indices SARC Provides Quota Recommendations For Each Region: Choose Between Available Exploitation Rates Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations
Stock Assessment Design Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations Strata designations (grids ~25 acres each) High Quality Medium Quality Low Quality Excluded from Survey Results in conservation
Stock Assessment Design Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations - High and medium strata-specific abundance estimates are summed for each bed. - The abundance estimates on each bed are summed within a each management region.
Stock Assessment Design Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations Recruitment Shell Budget Disease and Natural Mortality Fishery Statistics
Stock Assessment Design Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations Region-Specific Targets and Thresholds (Biological Reference Points) 9.0E+8 8.0E+8 7.0E+8 6.0E+8 Number of Oysters 5.0E+8 4.0E+8 3.0E+8 2.0E+8 1.0E+8 0.0E+0 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 Year - Baseline time period used to calculate Target/Threshold is 1989 2005. - Target is the median (green). - Threshold is ½ of the median (red). Stoplight Table: Abundance -Based Metrics, Disease and Mortality, and Recruitmen t
Stock Assessment Design Resurvey Stock Assessment Survey Estimate Uncertainty Review Metrics BRPs / Stoplight Quota Recommendations Harvest (# of oysters) 4.2E+7 3.6E+7 3.0E+7 2.4E+7 1.8E+7 1.2E+7 6.0E+6 0.0E+0 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year 2013 Quota Table Fishing rates based 1996-2006 harvests, a period of conservative fishing during Dermo era, that did not impact abundance Calculate the percent of the population harvested = exploitation rate These rates available to calculate quota Quota divided equally among licenses = catch share management Adding a license decreases every catch share
Delaware Bay direct market fishery has stabilized at an average of ~76,000 bushels.
Oysters build habitat Fishery harvests habitat Photo Credit: Jay Flemming Ecosystem health depends upon healthy reefs Local economy depends on healthy oyster fishery Managers must balance these needs
Shell planting is primary restoration tool. Presently, entirely industry funded by selfimposed bushel tax Plant ~150,000 bu/yr
Shell planting increases: oyster abundance oyster habitat oyster harvest Summer 2004 Spring 2005 Fall 2005 Fall 2003 Estimated economic impact is 25:1 on average Limitations: Funding, shell, regulations, labor
Observation Fishing Interests Farming Interests Conservation Interests
Oysters beget oysters Fishing Farming More Oysters in the Bay Conservation
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