Transcript Aslo Poster - University of Massachusetts Boston

COASTAL ECOSYSTEM MANAGEMENT IN WELLFLEET HARBOR, MA: ADDRESSING
SUSTAINABLE SHELLFISHING AND AQUACULTURE
AnneMarie Cataldo, Earth, Environmental and Ocean Science Department, University of Massachusetts Boston, [email protected]
Anamarija Frankić, Earth, Environmental and Ocean Science Department, University of Massachusetts Boston, [email protected]
ABSTRACT
Wellfleet Harbor has been well known for its oyster and quahog harvests and abundant
shellfish resources. Like many developed coastal areas, Wellfleet Harbor has been
experiencing increased population, landuse conversions, and tourism development, while
at the same time the abundance of its shellfish species has been declining. This is mainly
due to fishing pressure, habitat loss and alteration, water quality degradation and
shellfish diseases. However, Wellfleet continues to support a very active historical,
cultural and economically important shellfishing community. This project addresses how
to restore sustainable shellfishing and aquaculture development using coastal ecosystem
based management. Properly sited and established shellfish spawning sanctuaries
represent restorative and precautionary measures in fortifying the current spawning
population and increasing natural shellfish abundance. Using GIS and existing
environmental data, land use maps, and coastal and marine use zones, the site suitably
and use conflict analysis were performed (Frankic, 2003). Identified areas for potential
spawning sanctuaries were evaluated based on both environmental and Cape
socioCod
economical suitability analysis. Provided management recommendations have capacity
to forecast conflicts in a system that is evolving under both anthropogenic and climatic
forces.
Figure 1: Wellfleet Harbor
METHODS
RESULTS AND DISCUSSION
Environmental Site Suitability Analysis
According to the environmental site suitability analysis performed with available data, Wellfleet
Harbor has been classified for its ability to support the growth, survival and reproduction of the
oyster and quahog. The analysis was performed separately for the oyster and quahog, as
their environmental tolerances differ, and then the analysis results were combined for a map
displaying not suitable, suitable and optimal areas for both species (Figure 3).
• Determination of environmental conditions promoting growth, survival and
reproduction for Crassostrea virginica and Mercenaria mercenaria
•The generation of maps in ESRI’s ArcGIS 9.1 of selected environmental
parameters in Wellfleet Harbor using available data
•Classification of environmental parameters: a) not suitable for growth survival
and reproduction, b) suitable for growth survival and reproduction, and c)
optimal for growth survival and reproduction;
•Environmental data available from monitoring studies used in the analysis are:
Salinity, Temperature range, Spawning temperature, Dissolved Oxygen,
Bathymetry, and Fecal Coliform concentration;
• Using multiple criteria analysis in ArcGIS 9.1, performing the environmental
site suitability analysis of Wellfleet Harbor based on the not suitable, suitable
and optimal classification of environmental parameters;
Figure 3: Results of the environmental suitability analysis
Massachusetts
Cape Cod
Considering the initially suggested sites (Figure 2) it is clear that the site suitability analysis
has shown that most of these sites are not suitable for shellfish spawning sanctuaries (Figure
5). According to the analysis, only two sites: a) the deep water site and b) the creek north of
the Audubon Sanctuary, should be further considered as potential sites for spawning
sanctuaries. The deep water site is predicted to be environmentally optimal for both species
and without use conflict. The creek north of the Audubon Sanctuary is predicted to be
environmentally suitable for oysters, optimal for quahogs and without use conflict.
Figure 5: Results of the use conflict analysis combined
with the environmental suitability analysis
INTRODUCTION
Figure 2: Sites Suggested for spawning sanctuaries
Adding socio-economic factors in the use conflict analysis of the area resulted in expansion of
not suitable areas for spawning sanctuaries (purple polygons in Fig. 3).
Further considerations should be given to the adjacent land uses and current resource
management at the two potential sites: a) the creek site that is adjacent to the Audubon
Sanctuary is also close to residential zones. While the sanctuary would not create a problem,
residential zones create the potential for tenure disputes as well as runoff problems in the
adjacent coastal area.
Wellfleet Harbor
The draft of the 2002 Wellfleet Harbor Shellfish Management Plan suggested
several changes to the current management regime for the shellfish resource.
As part of an ecosystem based approach, the establishment of 6-10 small
mixed shellfish species spawning sanctuaries were proposed in this plan, with
six specific sites identified (Figure 2). The present study has set out to evaluate
if these suggested sites are suitable for the establishment of mixed species
spawning sanctuaries (Mercenaria mercenaria and Crassostrea virginica)
considering both environmental and socioeconomic factors of existing data for
the harbor. Considering environmental parameters, sites selected for spawning
sanctuaries must be conducive to the growth and reproduction of the two
shellfish species being considered. For socio- economic factors, a use conflict
analysis will need to identify areas that avoid use conflict with social and
economic activities occurring in and around Wellfleet Harbor. The present study
of site suitability analysis for spawning sanctuaries of Crassostrea virginica and
Mercenaria mercenaria will test for both environmental suitability and use
conflict in Wellfleet Harbor. Additional management considerations will also be
discussed so as to provide an easily understandable range of management
options for the decision maker.
Results on the Figure 3 shows that most of the harbor has environmentally optimal conditions
for both species. This optimal area occurs predominantly in the deeper parts of the harbor. A
large part of the harbor is also displayed as environmentally not suitable. This area covers
most of the intertidal flats. The main environmental indicator for the unsuitable classification is
the low temperatures and frequent ice cover during the winter that causes high mortality for
oysters in particular. Two other sites were selected as environmentally suitable for oysters
while optimal for quahogs, and environmentally suitable for both species.
Use Conflict Analysis (part of the Socio-economic considerations)
•Identifying and mapping present and future planned uses/activities in Wellfleet
Harbor (ArcGIS 9.1) (Figure 4)
• Selection of not suitable, suitable and optimal uses:
Not Suitable: Aquaculture, Mooring areas, Dredged areas and the Marina
Suitable: Areas of the harbor not being used for the previous purposes
Optimal: Areas of Subaquatic Vegetation (SAV)
• Using multiple criteria analysis in ArcGIS 9.1, and performing the use conflict
analysis to select suitable sites for shellfish spawning sanctuaries
Figure 4: Uses of Wellfleet Harbor
b) In order to use the deep water selected site for sanctuary the current shellfish management
and feasibility study must be considered. Because this part of the harbor is abundant in
commercially important shellfish and dredging is the main harvest method. Therefore, this
might be a potential future use conflict to establish a sanctuary in a dredging area for
commercial shellfishing. .
In conclusion, while spawning sanctuaries are proved to be one of the precautionary and
restorative measure for improving shellfish populations, they must be placed based on
environmental and socio-economic considerations in order to be effective. In Wellfleet Harbor
more scientific data can help in the decision making process (e.g. currents, benthic habitats,
non point sources of pollution, freshwater inputs). This approach and analysis identified gaps
in knowledge about the area as well as needed scientific data and monitoring needed in the
Wellfleet Harbor area.
REFERENCE:
Frankić, A. 2003. Integrated Coastal Management & Sustainable Aquaculture Development in the
Adriatic Sea, Republic of Croatia. Virginia Institute of Marine Science.
ACKNOWLEDGEMENTS: Town of Wellfleet Shellfish Department, Wellfleet
Health and Conservation Department, WHOI Sea Grant/ Cape Cod Cooperative
Extension, Massachusetts Division of Marine Fisheries