Portfolio III: Fisheries and Seafood Production

Targeted Issue: Utilization of the Blue Crab
for Soft Shell Product Forms

The Issue

Maryland is one of the leading producers of soft shell crab, wherein pre-molt crabs are harvested and held until they shed their shells, then removed from the water and sold live or processed and frozen. However, the molting process is highly stressful and, in order to minimize mortality of these valuable animals, various types of shedding systems have been employed. Maryland was one of the pioneers in working with watermen to apply recirculating technology to this industry. While Extension faculty have taught many programs using fact sheets in our Softcrab Workbook Series, in recent years we have helped foster stronger relationships among researchers in the University System of Maryland who are working on closed system development for fish, and are adapting their work to recirculating systems for shedding blue crabs. With concern over the decline of blue crab populations and the high mortalities that can occur in crab shedding systems, the need for working with soft crab producers to optimize their systems has become an important issue in Chesapeake Bay.

Our Response

Recirculating system technology has been applied to the holding and shedding of soft crabs for almost two decades now. Sea Grant Extension specialists have conducted group educational programs at the local, state, and regional level; these programs have employed program facts that have been supplemented by articles in the program newsletter Maryland Aquafarmer at relevant times of the year in order to target the shedders interest. The area educators have continued to provide individualized service to those having specific problems with design and management of their systems and have served as a conduit to the research community in order to identify industry problems. This role has led to the application of more sophisticated equipment in shedding operations and has provided continuing opportunity for high quality directed research.

Managing for Success

Maryland Sea Grant funded a Marine Engineering Specialist during the investigational and growth phase of this project. The Marine Engineer helped develop recommendations for system design and gathered background data on system operations. Several national meetings were held during this period in conjunction with Virginia Sea Grant. Publications were generated that supported teaching operations of the field staff. In recent years, work in Maryland has developed ties between Maryland Sea Grant Extension and University of Maryland Eastern Shore (UMES), Maryland's 1890 institution, which is engaged in developing and refining recirculating aquaculture systems for fish. One innovative design that has seen adaptation in the crab shedding industry is the multiple unit protein skimmer, which removes dissolved organics from the system water and decreases loads on the biofilters. This is important due to the cyclical loading of the system. Educational programs have been held in conjunction with the Maryland Watermen's Association's East Coast Commercial Fisherman's and Aquaculture Trade Expo, as well as invited presentations at programs by the New Jersey Aquaculture Association and other groups. In addition, due to the web based information on crab shedding posted in the program newsletter, questions and comments about crab shedding have been fielded from eight states and five foreign nations.

Achievements

A suite of fact sheets were produced that covered topics relating to water quality management and to extending the range of chemical test kits for more precise readings. Additionally, newsletter articles have served as continuing information bulletins on topics which range from system design and operation to methods of chemically starting biofilters. Placing Maryland Aquafarmer on the web has resulted in many soft crab producers contacting Maryland Sea Grant for answers to specific problems. If these operators are located in other Sea Grant states, the responder notifies the appropriate agent or specialist in that person's state to facilitate local follow-up. Work is ongoing with the UMES in order to assist with development of graduate student thesis topics that can target problems within the soft crab production industry. Consultation with the UMES group has also led to a draft fact sheet on the construction and use of protein skimmers in crab shedding as well as other topics that may be developed into written material for industry members.

Impacts

Sea Grant and UMES efforts have helped to lower mortality rates in the shedding operation, in many cases below ten percent, and have led to better utilization of the blue crab resource. This comes at a time when there are serious questions pertaining to the actual state of the resource in Chesapeake Bay and whether additional regulations may be required in order to protect the stocks. Maryland Sea Grant has long been recognized as a leader in this technology within the state and - as demonstrated by the on-line information requests we receive - has become a significant resource in other areas as well. The ties with UMES, reflecting a continuing desire for the 1890 and 1862 Land Grant institutions to work together, have allowed additional resources to be directed at this important industry through cooperative ties, joint activities and sharing of information.