Scallop Restoration News Flash

Recent News on Bay Scallop Restoration

Recent Marine Scene newsletter articles have highlighted efforts to survey bay scallop populations in southwest Florida and efforts to restore scallop abundance to levels not seen in several decades. The hope is that improved water quality and recovery of seagrass beds will set the stage for a recovery in local scallop populations.

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Scallop larvae ready to release. Photo courtesy Bay Shellfish Co.
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An adult scallop, ready for spawning, shows its characteristics blue 'eyes.' Photo courtesy Bay Shellfish Co.
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Scallop food. In these tanks are microscopic algae raised in the hatchery and fed to the scallop larvae. Photo courtesy Bay Shellfish Co.
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Booms are in place, ready for deployment of larvae.Larvae are also released outside of the booms. Photo by John Stevely
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Betty Staugler, Charlotte Co. Sea Grant Extension Agent, deploys larvae into the waiting booms. Photo courtesy Mike Braun
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Jim Culter of Mote Marine Laboratory deploys larvae into waiting booms. Photo by Jay Leverone

Experimental releases of scallop larvae raised in a hatchery are now underway. Scallops have been spawned and then cultivated for about 10 days until they reach the point where the swimming larvae are ready to settle out of the water and take up a bottom-dwelling existence. The hope is that by reducing their two-week free swimming larval stage, a much higher percentage of scallops will survive to settle.

Also, since they will not be floating about in the water for weeks they should settle out close to the release point and enable us to conduct surveys to see if the released larvae truly result in adult scallops. As part of the experiment, booms have been placed to temporarily constrain the larvae and hopefully ensure they settle where we can look for them when they have grown to a larger size. As part of the monitoring process, spat collectors have been placed to see if the young scallops settled near the release point. Spat is a term that refers to tiny scallops that have changed from the free- swimming stage to the bottom- dwelling stage that settles in seagrasses.

Scallop researchers have been busy in recent weeks. Earlier in December, scientists and volunteers with the Sarasota Bay Estuary Program, Sarasota Bay Watch and Mote Marine Laboratory have conducted larvae releases in Sarasota Bay and have plans for an additional release. Also, Betty Staugler, Charlotte Co. Sea Grant Extension Agent was out Sunday afternoon (Dec. 16,2012) with volunteers conducting releases in Charlotte Harbor. Funding for this work was provided by the West Coast Inland Navigation District.  Approximately 4-8 million scallop larvae were released at each event.

It must be remembered that this work must be considered experimental at this time. Although results of a similar release years ago were promising, we must conclusively demonstrate that released larvae successfully produce adult scallops capable of spawning. If there is success, we can try and gear up for larger scale releases. Millions of scallop larvae may sound like a lot, but only a very small percentage may survive and grow to be adult spawning scallops.

Years ago, attempts to transplant scallops from northern Florida proved to be unsuccessful. It is difficult and very expensive to transplant adult scallops on a large enough scale. Great care must be taken during hot summer conditions to ensure that scallops are not stressed. Even if they arrive alive, due to stress incurred during transport, their long-term survival and ability to spawn is in jeopardy.

There are no guarantees of success and that is why scientists are proceeding on an experimental basis. In the words of Albert Einstein, “If we knew the results before we started, we wouldn’t call it research.”

Keep your fingers crossed.

One Response to Scallop Restoration News Flash

  • John –

    Great article! Thanks for helping to keep Sarasota’s scallop restoration activities in the public eye. Community awareness and participation is the keystone of our restoration project.

    One of our strengths is that by banding together individuals, businesses and local organizations can make a difference and have a significant positive impact on the health and well being of the bay. To date our community has donated some $38,000 to scallop restoration! The long-term viability of the project depends on continued community support to sustain the multi-year effort that is needed if we are to succeed.

    Additionally, the outpouring of interest and support has been a spark for collaboration with Mote Marine Laboratory, Sarasota Bay Estuary Program and FWRI to wrap scientific expertise and data collection around community-driven restoration. It is a great pairing of interests – one where the scope of the coalition exceeds the reach of its individual constituents. I think that this could be a restoration model for other communities to emulate.

    To underscore the success of the collective effort, one needs look only as far as the accomplishments of the last 12 months:

    * Approximately 20 million scallop larvae released;

    * in various locations from Big Pass north to Sister Keys, encompassing the whole of Sarasota Bay;

    * using a diversity of release techniques (low density free releases, high density free releases and boom-contained releases);

    * near passes for good water flow and away from passes to minimize potential red tide challenges (as well as to diversify nutrient risks, predation risks, water parameter risks, poaching risk, etc.); and

    * with volunteers and marine scientists working together to do pre-release dive assessments of release sites, larval and juvenile spat collector deployment and boom placements.

    It should be noted that of the 20 million scallop larvae released to date about 20% have been in boom containment. When a boom is used we now are releasing 500,000 to 1 million into one boom, while another boom is left empty as a control, and the remaining larvae of the batch are free released at single point, or within a small area, in the vicinity of the booms.

    Here is a summary of our releases to date:

    Jim Culter of Mote Marine Laboratories is the keeper of scientific data (pre-release dive assessments, GPS points, temperature readings, red tide assessment, larval counts, larval spat collector counts, etc.) Sarah Stephenson (FWRI) is coming to Sarasota on January 8th to train people here in juvenile spat collector data collection.

    Finally, given our progress in releasing a substantial number of scallop larvae it is hoped that beds of adult scallops soon may be established locally. SBW feels that we, as well as other stakeholders, should endeavor to educate people that scallops cannot be harvested in our waters. Poaching, whether intentional or inadvertent, is a little known and widely misunderstood issue, one that constitutes a substantial threat to scallop restoration success. It would be great if you, in future articles, would add a sentence or two to help underscore this point.

    Thanks again for your continued interest in, and support of, this project. It is important and exciting for many reasons and to many people.

    Larry W. Stults, Ph.D., J.D.
    President of the Board
    Sarasota Bay Watch

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