Biological Control of Marine Pests Author(s): Kevin D. Lafferty and Armand M. Kuris Source: Ecology, Vol. 77, No. 7 (Oct., 1996), pp. 1989-2000 Published by: Ecological Society of America Stable URL: http://www.jstor.org/stable/2265695 Accessed: 10-06-2015 23:59 UTC Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at http://www.jstor.org/page/ info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Ecological Society of America is collaborating with JSTOR to digitize, preserve and extend access to Ecology. http://www.jstor.org This content downloaded from 128.111.90.61 on Wed, 10 Jun 2015 23:59:30 UTC All use subject to JSTOR Terms and Conditions Ecology, 77(7), 1996, pp. 1989-2000 ? 1996 by the Ecological Society of America BIOLOGICAL CONTROL OF MARINE PESTS1 KEVIN D. LAFFERTY AND ARMAND M. KURIS Department of Biological Sciences and Marine Science Institute, University of California, Santa Barbara, California 93106 USA Abstract. Biological control, as used in terrestrial systems, may hold promise for use against exotic marine species. We first review some marine pests, displaying their diversity, the damage they cause, and possible controls. We then contrast approaches for marine and terrestrial pest control, providing guidelines for adapting terrestrial controls to the marine environment. Although several of the same principles apply in terrestrial and marine en- vironments, marine systems differ with respect to the types of control agents available, the degree of pest-population reduction needed for effective control, the spatial scale over which biological control must operate effectively, the practicality of implementation, and the nature and degree of concern over safety. As an example, we propose a strategy for developing a biological control program against the European green crab, Carcinus maenas, which has had substantial negative impacts where previously introduced (New England, Atlantic Canada, South Africa, south Australia) and which has recently been introduced to central California, and to Tasmania. We conclude that biological control may be possible for some marine pests, but that existing strategies and expectations will require modification. Key words: biological control; biocontrol agents, safety testing of; Carcinus maenas; green crab; host specificity; introduced species; marine pests, biological control of; natural enemies; parasitic castrator; recruitment, importance of; Rhizocephala. INTRODUCTION of natural enemies (parasitic castrators, specialized predators, and pathogens of adults) that might normally Some species, often those that are introduced from control their abundance in their native regions (Lafferty elsewhere, are "pests" to the extent that efforts have and Kuris 1994). The resultant, extremely high popu- been made to control them in terrestrial and freshwater lation densities attained by alien species is what usually environments. Prior to the advent of chemical pesti- leads to economic damage (Nichols et al. 1990). cides, use of natural enemies of these pests was an important area of applied research, particularly in ag- There have been several recent calls for research on riculture. We now recognize the unfortunate environ- biological control of marine pests (Miller 1985, Moyle mental damage caused by some of these pesticides and 1991, Buttermore et al. 1994, Lafferty and Kuris 1994). we have repeatedly witnessed the development of ge- Australia's CSIRO (Commonwealth Scientific and In- netic resistance of pests. Hence, interest in biological dustrial Research Organization) Division of Fisheries control has been renewed. We now have an extensive has recently taken the lead in marine pest problems by body of practical and theoretical knowledge concerning establishing the Centre for Research on Introduced Ma- biological control, and a track record that includes rine Pests (CRIMP) in Hobart, Tasmania. CRIMP plans many successful applications interspersed with some a pro-active approach to marine pests in the style of notable failures. Biological control for these pest prob- Australia's historically aggressive and innovative use lems has involved the deployment of herbivores, pred- of terrestrial biological control. To stimulate further ators, parasites, or diseases. dialogue on control of marine pests, particularly intro- In marine environments, introductions are also com- duced species, we first briefly consider some marine mon and damaging (Carlton 1987, 1989, Zibrowius pests in U.S. waters. We illustrate the highly diverse 1991), but efforts at pest control have been limited to nature of these pests and focus on the type of damage conventional pesticides. Recent studies on mechanisms they cause and on considerations for their control. The of transport and establishment indicate that ballast wa- heart of our paper contrasts the general nature of marine ter, as a larval conveyance, is the most important means vs. terrestrial pest control, and we provide some guide- of dissemination (Carlton 1985, 1989). Since most such lines for the adaptation of existing biological control introductions arrive as larvae, they generally come free strategies to the unique challenges of the marine en- vironment. Finally, we present a case study of the in- I For reprints of this Special Feature, see Footnote 1, p. 1963. troduced European green crab, Carcinus maenas. Since 1989 This content downloaded from 128.111.90.61 on Wed, 10 Jun 2015 23:59:30 UTC All use subject to JSTOR Terms and Conditions 1990 SPECIAL FEATURE Ecology, Vol. 77, No. 7 this has been recognized as a serious pest and is a well- which may complicate the use of grazers as natural studied animal, we outline a general approach to its enemies. The high productivity of these introduced spe- control. cies on some reefs raises drag and causes the eventual loss of reef material (Russell 1992). On a positive note, SOME MARINE PESTS both species are now significant food sources for glob- The introduction of marine pests to new habitats is ally endangered green sea turtles, Chelonia mydas as old as nautical experience. Recall that Sir Francis (Russell and Balazs 1994). Drake had to rebuild the Golden Hind in California in Jellyfish.-Although it is apparently native, the sum- 1579, probably because it was riddled with (mostly) mer jellyfish, Chrysaora quinquecirrha, becomes pe- Atlantic shipworms. It is quite possible that this first riodically abundant in the Chesapeake Bay region, ship served to introduce a marine pest to California. reaching pest proportions. Its relatively powerful sting- So it is not surprising that introduced species such as ing nematocysts are responsible for intense burning Mytilus galloprovincialis and the western Atlantic pop- reactions among swimmers and those who must work ulations of the European green crab have planted them- around the water. Its presence has a negative but un- selves so firmly on our shores that most ecologists ac- measured impact on tourism in that area, as swimming cept them, without concern, as a naturalized part of the is often avoided. Jellyfish have sometimes become so biota. Many other introductions, particularly poly- abundant that they clog nets and block water-intake chaetes and amphipods, are cryptic and have been con- pipes (Ruppert and Fox 1988). Hyperiid amphipods sidered species with natural cosmopolitan distributions might be possible control agents. These generally host- (Chapman 1988). The following subsections describe specific amphipods act as parasitoids, parasites, or par- and discuss a series of well-known marine pests. asitic castrators on gelatinous zooplankton (Kuris Red and brown tides.-Red tides result from blooms 1974). However, biological control in this case may of marine dinoflagellates. For many years, these di- have risks. In Chesapeake Bay, C. quinquecirrha preys noflagellates have been considered cosmopolitan, and on, and may control, the ctenophore Mnemiopsis leidyi the increasing frequency of blooms a result of coastal (Feigenbaum and Kelly 1984). The cascading release eutrophication. Now it appears that some species have of M. leidyi from predation could lead to the sorts of been transported by ballast water (Hallegraeff 1993) or problems that occur now in the Black Sea, where M. with shellfish for mariculture (Shumway 1989). Red leidyi was introduced in 1982 (Vinogradov et al. 1989). tides can cause massive fish mortality, with consequent Achieving incredible densities there, it has altered the pollution of beaches and losses to fisheries. When algal food chain and led to the collapse of fisheries by con- toxins build up in edible shellfish, humans can die of suming a large proportion of the zooplankton (Harbison paralytic shellfish poisoning. Massive brown-tide and Volovik 1994). Ironically, two jellyfish from the blooms caused by chrysophytes have also caused heavy Black Sea have recently invaded San Francisco Bay mortalities of invertebrates and eel grass beds and have (Mills and Sommer 1995). severely impacted scallop fisheries. Algal consumers, Nemerteans.-Egg predators in the genera Carci- such as planktonic ciliates and heterotrophic dinoflag- nonemertes and Pseudocarcinonemertes can cause very