Author to Contact: Safra Altman
University of Connecticut
1084 Shennecossett Road
Groton, CT 06340
Telephone: 860-405-9167
Fax: 860-405-9153
Safra.Altman@uconn.edu

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Key Words: Crassostrea gigas, aquiculture, marine reserves

Crassostrea gigas, the Pacific oyster, is a common aquiculture species valued for its fast growth in cooler waters and its resistance to disease. With the spread of aquiculture, it is not surprising that C. gigas has become a common invader of marine systems. C. gigas has been cultured in the San Juan Islands, WA for over twenty years where cold water temperatures were believed to prohibit successful spawning in the wild.

False Bay is a marine reserve on the western shore of San Juan Island, owned by the University of Washington. This bay has been studied extensively by researchers for decades. We began annual surveys of the shores of False Bay in 1989. C gigas were first found in False Bay in the summer of 1997, and were noticed on other rocky shores around San Juan Island. All animals surveyed appeared to be of one age class. This recruitment was assumed to be anomalous, associated with several summers of warm water temperatures, and it was assumed that there would be no continued recruitment of C. gigas. In the summer of 2000, we resurveyed False Bay and examined two other University of Washington reserves on San Juan Island for the presence of C. gigas. We found C. gigas at all three sites in high densities. Continuous size distributions indicated the presence of newly settled young-of-the-year to animals at least 4 years old. At False Bay, individuals ranged in size (maximal shell dimension) from 7 to 175 mm, with a mean size of 94.2 mm (n = 388, std = 38.1). The individuals at Argyle Lagoon ranged from 20 to 222 mm, with a mean size of 80.7 mm (n = 403, std = 44.9). Oysters were also found on the beach in front of Friday Harbor Laboratories in the harbor of San Juan Island, ranging in size from 10 to 135 mm and with a smaller mean size of 71.4 mm (n = 441, std = 32.4). Oysters of all year classes were present at all sites. The source of young C. gigas is not clear. There may be local spawning in the bays and harbor, or a continued spread from local aquiculture facilities. Two of the sites, Argyle Lagoon and False Bay, are embayments and the local water currents may enhance probability of invasion and settlement due to larval retention.

The impacts of C. gigas within the three reserves is unknown. The capacity for C. gigas to filter water, to cover substrate, and the high densities found in all three sites suggest that impacts on local species may be large. We noticed the elimination of native primary space occupiers typical for the intertidal zone occupied by C. gigas. This work suggests that the safety of continued aquiculture of C. gigas in the Pacific Northwest should be reassessed.

Author to Contact:
Isabel Ashton
Department of Ecology and Evolution
650 Life Sciences, SUNY, Stony Brook, NY 11794
phone (631) 632-8600
fax (631) 632-7626
ashton@life.bio.sunysb.edu

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Key Words: Mytilus galloprovincialis, eastern Pacific, invasion, ecological resistance
 

The introduction and spread of aquatic invasive species (AIS) poses a serious threat to the marine and freshwater environments of Massachusetts. The proliferation of aquatic invaders has already had a significant impact on the economy and ecology of the Commonwealth, and AIS impacts in other states and countries convey the need to develop a proactive approach to minimizing the introduction and spread of nonindigenous species. This presentation gives an overview of the steps Massachusetts has taken towards a coordinated AIS management strategy, with emphasis on problems encountered along the way (related to both science and policy) and their solutions.

In the fall of 2000, Massachusetts formed the interagency Aquatic Invasive Species Working Group. The AIS Working group has sought to coordinate the patchwork of Massachusetts AIS management activities into a cohesive AIS Management Plan with the goals of 1) educating the public about the AIS problem 2) reducing the potential for AIS introductions 3) controlling the spread of established invaders and 4) minimizing impacts from established invaders. Key elements of this plan include the identification of existing AIS management activities, identification of priority invaders (including established and threatening invaders), and development of a five-year action plan. Major products, objectives, and future management actions which were developed by the AIS Working Group include in the Plan include:
· development of criteria for the designation of priority aquatic invaders;
· identification of priority transport vectors for marine and freshwater systems;
· development of emergency response plans for major taxa of colonizing invaders (i.e. aquatic weeds, shellfish pathogens, bivalves, etc.);
· designation of research priorities for AIS species and transport vectors;
· development of a state-wide AIS database; and
· development of educational tools and programs specific to priority invaders as well as the overall AIS problem.
The Working Group faced various difficulties relating to the coordination of marine and freshwater AIS management efforts, the designation of priority species based on limited research, and the identification of roles and responsibilities of various government agencies during the development of the AIS Management Plan. Thus, the Plan represents the culmination of extensive collaborative efforts between state and federal agencies, biologists, and other natural resource managers. The AIS working group seeks to have a plan approved by the federal Aquatic Nuisance Species Task Force by the fall of 2001 and, with the help of a full time AIS coordinator, begin implementation early the following year.

Authors to Contact:
Jason Baker
Nonpoint Monitoring Coordinator
Massachusetts Coastal Zone Management
251 Causeway St. suite 900
Boston, MA 02114-2136

Jan Smith
Director
Massachusetts Bays Program
251 Causeway St. suite 900
Boston, MA 02114-2136
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Key Words:  Marine Molluscs; Pest Management; Eradication; Maoricolpus roseus; Mytilopsis sp.

Twenty six species of introduced marine molluscs have been identified in Australian waters (Chad Hewitt, CSIRO, personal communication). Pest management options have been assessed for two of these species - Mytilopsis sp., the 'black-striped mussel' that arrived in Darwin in 1998 and Maoricolpus roseus, the New Zealand screwshell, that arrived in Tasmania in the 1920s and now forms dense beds on Australia's Southeast continental shelf. Mytilopsis sp. was detected within 6 months of its arrival and the decision made to eradicate it as soon as possible. Eradication was achieved rapidly and effectively as Mytilopsis sp. was restricted to two (perhaps three) marinas that could be closed off from the adjacent marine environment and poisoned with chemicals. However, continued entry of Mytilopsis sp. is occurring - indeed the indications are that entries are increasing - suggesting that we have not seen the last of this mussel. Maoricolpus roseus, on the other hand, was not detected by the scientific community until 40 years after its arrival, although scallop fishers had noted its presence many years earlier. Maoricolpus roseus now extends across Australia's eastern continental shelf from southern Tasmania to Sydney 1,300 km to the north and from MLW to at least 100 m depth. Control opportunities are limited - the obvious management opportunity is to restrict anthropogenic spread of the screwshell upcurrent and to the west. I use the case histories of these two mussels to examine Australia's responses to marine pest invasions and detail the scientific support that is needed to increase the effectiveness of those responses.

Author to contact: 
Nicholas J. Bax
CSIRO Centre for Research on Introduced Marine Pests
GPO Box 1538, Hobart, Tasmania 7001, Australia
phone 61-3-62325341
fax 61-3-62325485
Bax@marine.csiro.au

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Key Words: Mytilus galloprovincialis/trossulus, temperature, salinity, comparative physiology, stress response

To successfully invade a habitat and establish a viable population, an invasive species must be physiologically poised to cope with the physical environment. However, we know very little about the contribution of physiological adaptation to the success of invaders. The bay mussels in the genus Mytilus provide an ideal system for examining differences in physiological strategy between a native and an invasive species because they are closely related and inhabit the same sites. The native species (M. trossulus) and the invasive species (M. galloprovincialis) have an evolutionary distance of only 3 million years (Vermeij, 1991) and they co-occur, along with hybrids between the two species, in a hybrid zone from Monterey to Cape Mendocino, California. Within the hybrid zone, the proportion of each genotype is variable and the variability does not correlate with a strict latitudinal gradient (Sarver & Foltz, 1993; Rawson, et al., 1999). Mosaic hybrid zones such as this one are thought to be associated with differential physiological adaptation to physical conditions at each site. In the Mytilus hybrid zone, the distribution of genotypes correlates with both the salinity and, to a lesser extent, the temperature differences between the sites (Sarver & Foltz, 1993). Through a combination of laboratory experiments and environmental monitoring, I will investigate the connections among physiological adaptation, population genetics and environmental variability at each site. In this talk, I will discuss 1) the variability of the thermal environment of various sites within the Mytilus hybrid zone and 2) results from laboratory experiments looking at the differential response of each of the three genotypes to thermal stress and 3) the implications of these results for the observed pattern of invasion and distribution of Mytilus in this region.

Literature Cited:
Rawson, P. D., V. Agrawal, and T. J. Hilbish. (1999) Hybridization between the blue mussels Mytilus galloprovincialis and M. trossulus along the Pacific coast of North America: evidence for limited introgression. Marine Biology, 134:201-211.
Sarver, S. K. and D. W. Foltz. (1993) Genetic population structure of a species' complex of blue mussels (Mytilus spp.). Marine Biology, 117:105-112.
Vermeij, G. (1991) The anatomy of an invasion: the trans-arctic interchange. Paleobiology, 17: 281-307.

Author to contact: Caren E. Braby
Hopkins Marine Station
Oceanview Boulevard
Pacific Grove, CA 93950
phone: (831) 655-6238
fax: (831) 375-0793
e-mail: cbraby@leland.stanford.edu

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Key Words: Cancer productus; clams; Nuttallia obscurata; physical-biological coupling; predator-free space; soft sediment communities

A soft-shelled non-indigenous clam, Nuttallia obscurata, has invaded coastal soft sediment habitats of the northeastern Pacific. In a survey of 35 sites within the San Juan Islands, Washington, USA, Nuttallia was found almost exclusively in sandy substrates, higher in the intertidal than most native clams (> 1m above Mean Lower Low Water). Nuttallia's distinctive distribution suggested that tidal height and sediment composition may be important physical factors that control refuges available to Nuttallia, regulating its exposure to predation and ultimately the success of its invasion. I tethered Nuttallia for 24 hours in the high intertidal where it is typically found and in the low intertidal at an elevation where it was never found. Clams restrained to the surface suffered high mortality from crab predation at both tidal heights, whereas control clams with unrestricted movement exhibited high mortality rates only in the low intertidal. In a second experiment I transplanted sediment within and between the two intertidal heights to measure effects of tidal height and sediment type on Nuttallia's survival and burial depth. At both tidal heights all clams placed on mud-cobble substrate, naturally common in the low intertidal, suffered high mortality rates (> 60% in 24 hours). Nuttallia on loosely packed sand substrate, naturally found in the upper intertidal, however, survived much better because they buried deeper than in the tightly packed mud. Caged control clams at both tidal heights suffered no mortality. Apparently native predators are mitigating community level impacts of an invader by excluding Nuttallia or relegating it to a zone not often inhabited by native species, thereby reducing potential competitive interactions. These findings illustrate that a physical characteristic can mediate biotic resistance to an invader and thus control invasion success and community-level impacts. Generally, such physical-biological interactions may explain some of the reported site-to-site variability in invasion success.

Author to contact: James Byers
Friday Harbor Laboratories
620 University Rd.
Friday Harbor, WA 98250
jbyers@u.washington.edu
Fax: (206) 543-1273

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Key Words: Volunteers, 4-H, youth, citizen engagement

Overview
A novel approach for enlisting citizen help with the control of purple loosestrife has been successfully instituted. Classroom curriculum teaching students to raise and release Galerucella beetles was adapted for the nonformal youth audience. The curriculum was pilot-tested in three states with 4-H youth groups. The 4-H youth, their leaders, extension educators, and technical experts evaluated the curriculum. Their feedback was used to improve the final curriculum.

Background
Citizen groups are often looked to for assistance when the scope and magnitude of nonindigenous species infestations exceeds the capacity of professionals. Adults are usually enlisted to assist professionals but youth, under the direction of classroom teachers, are occasionally utilized. The guidance of a dedicated teacher with the time and other resources necessary to help control nonindigenous species infestations can be a great benefit to professionals. Due to the increased pressure to teach specific science standards, however, teachers often find it difficult to implement these projects and give time to studies outside the mandated subject matter that they must teach. Many teachers are also finding it increasingly difficult to take their students on the field trips that are required when working with invasive species. Furthermore, unless a school system has year-around-school class may not be in session when the fieldwork needs to be done. For these reasons project personnel decided to look to the nonformal audience for assistance with control of an invasive, nonindigenous species.

Procedure
The nonformal curriculum was based on and adapted from two excellent classroom teaching resources (The Purple Loosestrife Project Cooperator's Handbook (Chapman, D., et. al) and Biodiversity, Wetlands, and Biological Control: Information and Activities for Young Scientists. Purple Loosestrife: A Case Study, Teacher Training manual (Jeffords, M.R. et al.)). Because of the scientific and technical nature of the information it was necessary to use a network that would allow for training, dissemination of information, and continued contact with project groups. The U.S.D.A. Extension system, particularly the 4-H youth component, met these criteria. 4-H youth groups exist in every state. Extension educators guide the work in collaboration with state specialists located at land grant universities and working with other professionals (such as Sea Grant and Departments of Natural Resources). This network provides contacts for information dissemination, feedback, university expertise, and continuing support.

The major challenge in adapting the curriculum for the nonformal audience was the need to reduce the depth and breadth of information presented in the original classroom curriculum. 4-H groups meet much less frequently than conventional classes, sometimes on a weekly, or even monthly, basis. Furthermore, the volunteer leaders working with the youth come from a wide variety of backgrounds. They may have very little scientific training or they may be professional scientists themselves. The amount and depth of material to be presented and discussed must be clear and concise. Although this constraint is seen as problematic to some professionals there are two offsetting features of the 4-H youth audience that make it possible to be successful: first, the volunteer leaders and youth want to do the project and are interested in being involved. The have voluntarily chosen to participate, they are not forced to listen because it is a science class with tests and exams to worry about. Secondly, 4-H uses a "hands-on" approach that many learners find much more interesting and educational than traditional classroom teaching.

Curriculum manuals were developed for a high school aged audience. Youth manuals contain ten "learn by doing" activities. A leader's guide contains the same activities with the correct (or suggested) answers, background information, suggestions for working with high school aged youth, and additional resources.

Draft curriculum was usually presented at a training workshop for volunteer 4-H leaders although in two cases 4-H leaders did not receive training before using the manuals. The workshop included an overview of the problems caused by the invasive species (particularly purple loosestrife), possible control methods, and an introduction to the curriculum. The 4-H leaders used the youth manual and leader's guide in their club meetings with 4-H youth in a number of different ways. Two 4-H leaders used the manuals with existing 4-H clubs (an Entomology and a Soil & Water Conservation club). They included the purple loosestrife biological control activities as an add-on to their existing programming. Another leader, a former high school teacher new to 4-H, started a new project group that focused only on biological control of purple loosestrife. This leader sparked the interest of the local media and had three write-ups in local papers. The youth manual and leader's guide were also used in a summer camp setting with youth ranging in age from upper elementary through middle school and by a parent working at home with her daughter. These leaders reported a high level of youth interest and involvement and in all but one club the youth developed educational displays for their county fairs.

The leaders, extension educators, and youth provided feedback both formally and informally about the usefulness of the manuals, the training workshop, and support they had during the pilot-test phase of the project. Technical experts (Sea Grant and the Natural History Survey) also reviewed the draft manuals and provided feedback. All feedback was used to make improvements to the curriculum. The final curriculum will be submitted to National 4-H for juried review. If accepted by National 4-H the curriculum will be made available to 4-H members and leaders nationwide.

The specific steps that were used in the curriculum development were:
· Connection with people working with biocontrol of nonindigenous species for content, presentation methods, and techniques
· Adaptation of classroom materials for a nonformal audience
· Pilot-test of draft materials in 3 states (IN, IL, MN) through the Extension system (4-H Youth Development)
· Compilation of feedback, evaluation of feedback with project personnel, incorporation of suggestions into the curriculum
· Professional design and layout of curriculum
· Dissemination of materials

The linkage of Sea Grant program experts and the Cooperative Extension system of county educators, 4-H volunteer leaders, and youth offered a unique approach to involving citizens in controlling a local invasive species. Technical and youth development expertise was necessary to create, pilot-test, evaluate, and update the curriculum materials. The collaboratation worked very well in producing a high quality, nonformal curriculum for high school aged youth.

References:
Chapman, D., Corlew, M., Dann, S., Francke, L., Haas, M., Heidemann, M., Hesselsweet, A., Klepinger, M., Landis, D., Parker, J., Potter, J., Sebolt, D., The Purple Loosestrife Project Cooperator's Handbook, Michigan State University, Teacher Training manual (in progress).
Jeffords, M.R.; Post, S.L.; Wiedenmann, R.N.; Voegtlin, D.J., Biodiversity, Wetlands, and Biological Control: Information and Activities for Young Scientists. Purple Loosestrife: A Case Study, Teacher Training manual (in progress). Collaborating entities: Illinois Natural History Survey, Chicago Wilderness, U.S. Fish & Wildlife Service, and the Illinois Department of Natural Resources.

Author to contact: Natalie Carroll, PhD
4-H Youth Development Department
1161 Agricultural Administration Building
Purdue University
West Lafayette, IN 47907-1161
Phone: (765) 494-8433
Fax: (765) 496-1152
E-mail: ncarroll@purdue.edu

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Recent findings give reason to call into question the current analysis of the problem of nonindigenous species and the efficacy of the regulations adopted to deal with the international transport of pathogens. We propose to identify and discuss this problem, demonstrate why the current approach may be ineffectual and suggest a methodology to analyze the problem and develop an effective regulatory solution. The transport of pathogens, organisms that produce disease in plants or animals, as well as nonindigenous species has been recognized and documented within the past few years .
A study recently released by the Smithsonian Environmental Research Center reported that fifteen ships traveling from European and Mediterranean ports to ports in the Chesapeake Bay tested positive for pathogenic viruses and bacteria . Until now, the focus in the United States has been on the ecological consequences of bio-invasions by exotic species with virtually no consideration of the public health implications of the introduction of pathogens. The identification of pathogens among those species being transported now brings into question certain assumptions that have been the foundation of interim measures adopted such as at sea exchange of ballast water. The National Invasive Species Act of 1996 (NISA) directed the Secretary of Transportation to promulgate regulations that (a) require vessel masters to report their ballast water management practices when entering United States waters from beyond the 200 mile Exclusive Economic Zone (EEZ) and (b) describe a regime of voluntary ballast water management practices for use by such vessels. The voluntary guidelines include holding ballast water on board and open-ocean exchange of ballast tanks that will be discharged in United States waters. The purpose of the prescribed management practices was to (1) minimize the transfer of non-indigenous species in ballast water of ships and (2) reduce the risk of exotic species invasions associated with the release of ballast water. Except for one brief mention in the Congressional Record, pathogens were virtually ignored in the discussions of NISA and the regulations adopted pursuant thereto. While it was noted that ballast water capable of transporting mussels and fleas can also transport a human bacterial pathogen such a Vibrio Cholera, neither the Act or the following regulations focused on the public health implications of coastal water contamination by ballast water.
The Interim Report of the National Ballast Information Clearinghouse recently reported that only 20.8% of the vessels that entered United States waters from outside the EEZ filed mandatory reports with the Clearinghouse and of the 3,560 vessels that reported an intention to discharge ballast water only 21.4% reported having conducted a complete mid-ocean exchange of the volume of water to be discharged. It appears that the regulations, which clearly were not intended to deal with pathogens, are being honored in the breach. We suggest that it is necessary to establish a methodology to deal with the problem of pathogens in ballast water using sound scientific principles and effective legal controls.
The current available knowledge is limited to the following: pathogens are being transported in the ballast water of ships; these organisms pose a health threat to many species including humans, marine mammals, fish, mollusks and shell fish; and, these organisms are able to survive in ballast water despite adverse conditions. Increased scientific knowledge is essential before an adequate solution can be formulated. Solutions will require techniques that must rely on complementary scientific and legal disciplines.
Proposals that have been made to date have not been successful in removing pathogens from ballast water or for that matter truly addressing the problem of the transport of other non-indigenous species. Some have suggested that at sea exchange, the only solution attempted to be implemented thus far, is less than 100% effective in removing organisms from ballast water, can pose a significant threat to the crew and cargo of ships in heavy seas and may also deposit contaminated ballast into high speed ocean currents with the potential of causing increased dispersal at areas located "downstream" of reballasting areas. Several individual states have passed statutes that were not based on scientific knowledge or sound technology and present a complex regulatory labyrinth, which interferes with international trade. Currently, research is being conducted to define mechanisms that will decrease the numbers of pathogens and invasive macro species in ballast. We propose that acceptable scientifically sound standards must be established as the foundation of regulations that will encourage the development and application of technological solutions. Until scientific methodology has determined the nature and extent of the problem and the appropriate standards have been developed and codified, no enforcement process can be set in place. Then and only then will an environment be established that will encourage the development of scientifically sound technology.

Author to contact: Gloria A. Casale
Health Resources and Services Administration
Center for Quality
Parklawn Building
5600 Fishers Lane
Rockville, MD 20857
(301) 443-6205
gcasale@hrsa.gov

Hugh H. Welsh
One World Trade Center, 67 East
New York, NY 10048
(212) 435-6915
hwelsh@panynj.gov

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KEY WORDS: Exotic, Introduction, Interspecific competion, Japanese Shore Crab, Green Crab

The intentional or accidental introduction of exotic species into North America is a great threat to the integrity of natural communities of plants and animals and to the preservation of endangered species (Carlton 1995). The effects of exotic species in marine systems have not been as well studied, but are potentially of such a magnitude that they may result in profound ecological changes in the structure ocean communities (Carlton and Geller 1993). Long Island Sound has a long history of maritime commerce and it is likely that it's species composition changes yearly because of the release of exotic species that are taken up in this manner. There are more species in Long Island Sound this year than last (Carlton 1985). Hemigrapsus sanguineus is now well established and rapidly expanding it's range along the Atlantic coast of the United States from Chesapeake Bay to Cape Cod (Carlton 1995). Williams and McDermott (1990) first recorded Hemigrapsus sanguineus in the United States on 24 September 1988 during an invertebrate biology course field trip at Townsends Inlet, Cape May County, New Jersey [39o 07'06''N 70o 43'00"W]. Twenty months later (28 May 1990) an immature female was recovered (McDermott 1991). This second finding suggested that the first record of the species in New Jersey was representative of a population already established in U.S. waters. This discovery provides a unique opportunity to document a major introduction to U.S. waters (McDermott 1991).
Hemigrapsus sanguineus is now extremely abundant on the Connecticut coastline. H. sanguineus is thought to exploit different, but overlapping habitats on cobble and boulder shores in rocky inter-tidal habitats (Fukui 1988). In areas where the Green crab (Carcinus maenas Linneus), used to be abundant H. sanguineus is the most common observed species. Few Carcinus maenas are now found. Changes in abundance and/or distribution may be the result of inter-specific competition between the two species for food and habitat. The focus of this study was to determine the relative abundance of H.sanguineus at two specific sites on the Connecticut coastline. The possible inter-specific competition between H. sanguineous and C. maenas was determined through studying each species' population density and distribution along the rocky inter-tidal zone at each site.
Two study sites were selected based on their central locality along the Connecticut shore and the large percentage of rocky inter-tidal shoreline, which Carcinus maenas and Hemigrapsus sanguineus seem to prefer. The two sites chosen were Outer Island, Stony Creek and Hammonasset State Park, Madison
Three transects were laid out at each sampling site delineating each tidal zone: the high inter-tidal zone, middle inter-tidal zone, and low inter-tidal zone. Each transect ran parallel to the water line. Both at Outer Island and Hammonasset State Park each transect were divided into quadrants measuring 1m2. The location of these stations was marked with stakes and through marking specific boulders with paint. Five quadrats at each station were randomly selected for each sampling period at Hammonasset State Park, where at Outer Island each quadrant was sampled at each sampling period.
Sampling at each station was conducted where all the boulders within the quadrant to the underlying gravel within a depth of approximately 5 cm were turned over to hand capture both H. sanguineus and other native crab species including C. maenas. Crabs were placed in labeled jars upon capture field preserved in a 10% buffered formalin solution until analyzed. The number of crabs for each species recovered from each quadrat was determined. Each crab species was identified through the Guide to the Atlantic Seashore (Gosner) and measured to the nearest 0.1mm with vernier calipers. Each crab species was recorded as a member of relative size categories determined by Yasuo Fukui (1988): less than 9mm were considered juveniles, 9.1mm-18.0mm-small, and 18.1+mm-large (adult). Crabs were then sexed and ovigerous females were determined. Temperature and Salinity for each sampling period at each site were recorded at the beginning of the sampling period using a YSI salinometer.
Results presented in this study clearly showed that H. sanguineus is numerically dominant in most areas of the intertidal zone at the sites studied. C. maenas were observed but in extremely low numbers at both sampling sites were historical data indicates they were once abundant. No other crab species were found at either Outer Island or Hammonasset with the sampling areas used for the duration of the study. H. sanguineus were found in areas of very high concentrations of amphipods throughout the mid and low tidal zones, although whether they have been using these amphipods as a food source is unknown. In areas of dense Fucus sp. cover results showed no medium to large male and female size classes of H. sanguineus were not found. However, C. maenas were present in Fucus sp. occupied areas.
The highest total numbers of H. sanguineus were distributed from the low to the mid tidal zone at both sampling sites for the May and June sampling periods. A spatial shift towards the mid tidal range was observed during July, August and September sampling periods where numbers were extremely high. For the same period, numbers of crabs in the lower tidal zone decreased. This could be a result of the colder water temperatures in September. This suggests that the largest number of crabs in each size class would shift to higher zones because of possible lack of tolerance for the colder water temperatures. Male and female crabs of the larger class sizes showed little or no spatial preference for any portion of the intertidal region during any sampling period. This could be a result of a higher tolerance for temperature changes as crabs mature and grow larger. There were no differences between larger crab sizes and sex (male vs. female), however with the smaller size classes males were numerically dominant early in the year with females becoming dominant towards September. There were small correlation's between smaller size classes and rock sizes varying between 80-100mm. Here small trends were noticed. As rocks became larger there was absolutely no correlation.

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Author to contact: Casanova, Tara.
Cedar Island Marina Research Laboratory
Clinton, CT 06413
Telephone: 860-669-8681 ext. 19
Fax: 860-669-4157
Taracimrl@aol.com

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