Pathways and Prevention : Marine Bait
What is the Problem?
Live marine worms are used as bait in sport fishing. The polychaete or segmented worms are packed in a brown seaweed (Asphyllum nodosum) and shipped throughout the country. Other species may survive the journey and become introduced in new locations.
Photo: Tessa Getchis, Connecticut Sea Grant
The use of live marine worms for bait in sport fishing is common practice all over the world. Various species of worms are harvested from tidal mud flats, packed into larger containers called "flats," and shipped around the world. In the Northeast U.S., the bait worm industry is small but significant.
In the state of Maine, the focus of the live bait problem is on the pileworm Nereis virens and the bloodworm Glycera dibranchiata. Flats of 125 to 250 harvested worms each are packed with a brown seaweed commonly known as "wormweed" (Ascophyllum nodosum) and shipped to distributors, who then ship the flats to retail operations on the Atlantic or Pacific coasts, or to Europe. Individual bait dealers and retail operations then divide the contents of the larger flats among smaller boxes or bags for retail sale. Sport fishermen purchase the live bait in the boxes for use during their fishing activities.
What are we concerned about?
The seaweed used as packing material to keep the worms moist and alive during shipping may be harboring other live organisms, including juvenile shellfish, small crustacea (crabs, amphipods, and isopods), snails, and other worms. Cohen et al. (2001) report that 38 distinct species were found among samples of baitworm shipments arriving in California in addition to the baitworms and seaweed used for packing material. If the seaweed is discarded into the water at any point along the distribution path or during the end use by an angler, those organisms will also be discarded.
Results of a survey of anglers indicated that they discard at least 30% of the seaweed packing into the water or the intertidal zone (Lau 1995). It is possible that some could survive and become established. If the ecosystem into which they were discarded is not their native ecosystem, they could become an introduced species. Scientists believe that three invasive species on the Pacific coast may have been introduced via this pathway: the European green crab (Carcinus maenas), the periwinkle (Littorina saxatilis), and the green seaweed known as Green Fleece or Deadman's Fingers (Codium fragile tomentosoides) (Cohen et al. 1995).
What are the solutions?
There are several possible ways to "interrupt" this pathway of introduced species. One way is to find acceptable alternatives for packing the live worms. The use of shredded newspaper and salt water has been explored (NEED REF). A second way is regulatory, with individual states (or countries) banning the use of fresh seaweed as a packing material for live marine worms. A third means is through education of the end-users of the bait, the anglers. Educational messages in the form of placards in bait dealer shops and stickers on individual bait boxes can serve to remind anglers to "protect their fishing waters". By simply disposing of bait boxes and the associated seaweed packing material in the trash, not in the water, fishermen can help prevent unintentional introductions of organisms to a body of water.
Cohen, A.N., Weinstein, A., Emmett, M.A., Lau, W., Carlton, J.T. 2001. Investigations into the introduction of non-indigenous marine organisms via the cross-continental trade in marine baitworms. Report for the U.S. Fish and Wildlife Service, Sacramento CA. 29pp.
Cohen, A.N., Carlton, J.T., Fountain, M.C. 1995. Introduction, dispersal and potential impacts of the green crab, Carcinus maenas, in San Francisco Bay. Marine Biology 122:225-237.
Crawford, S. 1999. Live rockweed (Ascophyllum) used as a shipping medium for the live transport of marine baitworms from Maine. Marketing and Shipping Live Aquatic Products. Proc. 2nd Intl. Conference and Exhibition, Seattle WA. (Paust, B. and A. Rice, eds.)Univ. Alaska Sea Grant Report No. AK-SG-01-03, p. 95-98.
Lau, W. 1995. Importation of baitworms and shipping seaweed: vectors for introduced species? Pp. 21-38 in: Sloan, D., M. Christensen, and D. Kelso (eds.), Environmental issues: from a local to a global perspective. Environmental Sciences Group Major, University of California, Berkeley, CA.
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