Best management practices for the control of blister worm on oyster farms

Best management practices for the control of blister worm on oyster farms

Summary

Blister worm is a polychaete worm that burrows into the shells of oysters; infestations create visible pockets or blisters of mud and fecal waste that mar the oyster’s appearance when served on the half-shell. If these blisters are broken the resulting off-flavor causes catastrophic impacts on market value of farmed oysters. Reducing the impact of disease-causing and pest species has been a top priority for oyster growers in the Northeast. Our research and education program targets the onset of pest infestation to eliminate the need for costly treatment of infested oysters. During this reporting period, we worked closely with three oyster farms in Maine affected by blister worm. At each farm, we applied treatments designed to reduce the initial colonization of oysters by blister worm. We are currently compiling and analyzing the data from this research. We presented the preliminary results of our work at an international meeting in Massachusetts in October 2015 and plan to present the results at two winter meetings attended by oyster growers in Maine and Connecticut and an international meeting of aquaculturists in Las Vegas. We will also use these meetings as an opportunity to disseminate information on our blister worm impact survey and the education/training aspects of our project, most of which will take place in the summer of 2016.

Objectives/Performance Targets

Twenty northeastern oyster farms with annual aggregate sales of about $4 million will each implement a comprehensive polychaete pest management plan. This will reduce pest prevalence and improve crop quality compared to prior years, avoiding an estimated $4 million aggregate loss in annual sales.

Accomplishments/Milestones

1. 1000 members of the East Coast Shellfish Growers Association receive updated on-line survey on the impact, prevalence and distribution of blister worm and invitation to participate n bluster worm education program. In progress – there were delays in getting industry comments back on the draft of our survey. We plan to begin distributing the survey electronically and at regional meetings January to March 2016.
2. 100 oyster growers return survey (10% return rate), and 80 express interesting in joining education program. Expected completion May 2016.
3. Research component of project testing preventative treatments for blister worm established at two oyster farms in Maine. Workers at these farms receive training in monitoring for blister worm larval abundance (plankton sampling), settlement, and reproduction. Due to delays in receiving funding, this research was conducted between May and November 2015. We expect to complete our analyses and distribute full project results by March-April 2016.
4. Participants in blister worm education program receive regular email/blog updates on project progress and efficacy of preventative treatments. October 2016.
5. 40 farmers attend first workshop at the Milford Aquaculture Seminar on blister worm biology, reproduction and settlement, receive update of project goals and progress and begin development of best management plans for blister worm prevention. February 2017.
6. Second year of activities testing preventative treatments for blister worm established at two oyster farms in Maine. March-April 2016.
7. Fact Sheet on blister worm biology, reproduction, and population dynamics, and preventative treatments for blister worm distributed to 1000 members of the East Coast Shellfish Growers Association. Completed September 2015.
8. 60 farmers attend site visit at either of our two grower-participant farms to receive hands on training in blister worm prevention. July 2016.
9. Additional 40 farmers attend second workshop at the Northeastern Aquaculture Conference and Exposition on blister worm biology, reproduction and settlement, receive update of project goals and progress and begin development of best management plans for blister worm prevention. December 2016.
10. Twenty farmers utilize educational opportunities, outreach materials or site visits to develop, adapt and adopt best management protocols resulting in reduction of blister worm impacts on market viability of oysters. October 2017.

Impacts and Contributions/Outcomes

The research portion of our project was originally targeted for two oyster farms in Maine that have been impacted repeatedly by blister worm. We had the opportunity to expand to a third farm, with each farm located on a different estuary/river, providing us with increased replication and the ability to assess whether the same types of treatments work well in different waters. All three farmers provided us with access to their farms, assisted us with deploying cages, provided the oysters that were deployed in the caging system, and granted taped-interviews explaining their role in the project. We plan to edit the latter to provide an additional form of on-line training material on managing blister worm. Based on the results from an initial experiment we conducted in 2014, all three farmers have shown great interest in or have actually begun to use at least one version of our proposed treatments on their farms. Thus, we can compare our project results to the incidence of blister worm in their regular operations and use the comparison in our training materials. We also saw progress on the education portion of our project. We accelerated our work on a FACT SHEET on blister worm and have made this document available on-line (http://www.seagrant.umaine.edu/files/Dana%20Morse/PolydoraFactSheet_Web_101515.pdf), although at present we do not have an accounting of the number of downloads. We have developed the farmer survey and received some feedback on the survey content. It has taken longer than anticipated to prepare this survey but we expect to distribute this survey broadly at the beginning of 2016. This survey will also serve as one of our major recruiting tools for our training and education activities during 2016.

• Blister Worm FACT SHEET for growers

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