Diversification

Diversification for the Hard Clam Aquaculture Industry Through Investigation of Blood Ark and Ponderous Ark Culture and Marketability

Investigators:
Dr. Bob Degner, University of Florida, Food and Resource Economics Department
Jose Nunez, University of Florida, Department of Fisheries and Aquatic Sciences, The Whitney Lab
Leslie Sturmer, University of Florida, Cooperative Extension Service
LeRoy Creswell, University of Florida, Florida Sea Grant Program
Dr. Shirley Baker, University of Florida, Department of Fisheries and Aquatic Sciences
Randal Walker, University of Georgia, Marine Extension Service
Alan Power, University of Georgia, Marine Extension Service

Funding:
U.S. Department of Agriculture, Cooperative State Research, Education, and Extension Service

Time Period:
2001-2005

Objectives:
The goal of this research is to determine the feasibility of establishing a commercial aquaculture industry for producing the blood ark, Anadara ovalis, and the ponderous ark, Noetia ponderosa. The overall objective of this project is to investigate the aquacultural and market potential of both ark clams, and to educate shellfish aquaculture industry members, in particular hatchery operators and wholesale dealers, as to the seed rearing requirements and market attributes of these alternative molluscan shellfish species.

Our specific objectives are:

To histologically determine the gametogenic cycles of the blood ark and ponderous ark off the east and west coast of Florida, respectively.
To develop reliable spawning and larval rearing techniques for the production of blood ark and ponderous ark.
To define and evaluate culture techniques to optimize survival of both ark clams at settlement (metamorphosis).
To monitor the production performance (survival and growth) of ark clams during the field nursery and growout phases using culture techniques similar to those for hard clams.
To assess the magnitude of the potential domestic market for both ark clams.
To determine product attributes desired by the seafood trade, especially size, color, shell appearance, taste, nutritional analyses, and shelf life in customary refrigerated storage.

This project will contribute to solving a current problem with the lack of diversification in the hard clam industry by evaluating two marine bivalve species. These species could supply alternative or supplementary products for the shellfish aquaculture industry in the Southeast. Further, a partnership among the clam farming community, the UF Institute of Food and Agricultural Sciences and the UGA is developed to focus and leverage available resources to enable the sustainable development of shellfish aquaculture.

Accomplishments To Date:
Spawning, Larval Rearing, Nursery and Growout Culture
An experimental molluscan shellfish hatchery was established during 2001 at the UF Whitney Lab near St. Augustine by retrofitting existing laboratory space. The 288-sq. ft. room contains the following components: 1) spawning table; 2) larval rearing area, consisting of four conical bottom larval rearing tanks of 150 gallons capacity each; 3) post-set rearing area, consisting of two 100-gallons raceways and appropriately sized downwellers; 4) aeration unit, provided by a linear piston air pump; and, 5) phytoplankton culture area, containing six 45-gallons Kalwall algal culture tubes, eight 5-gallons carboys, and fluorescent lights on a timer with a total production capacity of 310 gallons of algae. Seawater from the Atlantic Ocean is obtained by an existing pump station and is pre-filtered through 25,10, 5 and 1 micron filters before being sterilized by an ultraviolet sterilizer. During 2003, an experimental land-based nursery, consisting of fiberglass tanks and wellers, was constructed at the same location. A submersible pump system provides unfiltered water from the Intracoastal Waterway to the nursery system.

Adult blood and ponderous arks were collected from wild populations around the Ponce de Leon Inlet, Mosquito Lagoon and Cedar Key area and held in existing facilities at the Whitney Lab for use as broodstock in spawning and larval rearing trials conducted during 2001-3. Upon examination of gonadal development, animals were either induced to spawned or held in maturation tanks for later spawning efforts. During the same time period, monthly samples of live blood ark and ponderous ark clams and water quality conditions at the collection sites were provided to UGA faculty at the Shellfish Lab in Savannah for determining histologically the gametogenic (spawning) cycle of these bivalve species. In a separately funded project (Florida Sea Grant), researchers at the Florida Atlantic University documented the embryological development of ark clams during the spawning trials.

To date, preliminary data indicates that both species can be raised to juvenile stage. Spawning of ark clams was induced by temperature cycling. The time from fertilization to setting varies from 21 to 28 days in the ponderous ark and from 16 to 21 days in the blood ark. Further studies on improving the setting rate are needed and will be addressed during the spring of 2004. To evaluate growout methods, 10,000 blood ark clams have been planted in both polyethylene bags and polyester (clam) bags at commercial densities in the field.

A final report describing the gametogenic cycle, embryological development, and results from spawning, larval rearing, nursery and growout trials of the ponderous ark and blood ark is in preparation by researchers at UF and UGA. Since nothing is known about the biology of these populations in Florida’s coastal waters, these efforts will assist the commercial interests in developing reliable production techniques.

Marketability
A market survey developed by Dr. Degner with the UF Agricultural Market Research Center was sent to 2,134 certified wholesalers identified through the FDA’s Interstate Shellfish Shippers List in 2002. Results from the nationwide survey quantified the shellfish wholesaler trade's present awareness and acceptance of ark clams, and, in turn, were used to assess the magnitude of the potential domestic market for these alternate molluscan species. The survey revealed extremely limited trade awareness of the two species of ark clams. Over 90 percent of all shellfish dealers were unfamiliar with them. Only one percent of responding firms reported selling these species of clams at present, and sales were very limited. Unfortunately, these results did not capture the presumed demand by both Asian and Hispanic ethnic groups for these bivalves. However, nearly one-third of all respondents were willing to evaluate product samples of both species.

The second phase of the marketing study was initiated in 2003. After obtaining appropriate shipping materials and developing another survey, "marketable" sizes of ponderous arks and blood arks were obtained from respective test sites in Cedar Key and in St. Augustine and New Smyrna Beach. A shellfish wholesaler in Cedar Key assisted in processing, tagging, and cold storing the arks after harvest. In November samples of live product were sent via overnight courier to 92 shellfish wholesalers throughout the nation who expressed interest in the initial survey. Results from the second survey will be assessed to determine the product attributes desired by the seafood trade. A final report will be made available to interested shellfish wholesale dealers.

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