Blood, Bait, & Birds: The Horseshoe Crab, A Multiple Use Resource

Transcription

1 Blood, Bait, & Birds: The Horseshoe Crab, A Multiple Use Resource Mary-Jane James, PhD Graduate School of Oceanography University of Rhode Island mjjamespirri@uri.edu

2 Older juveniles and young adults migrate to deeper water. Young juveniles reside on intertidal flats. Life Cycle Female Males After adults reach sexual maturity (9-10 years), they return to beaches to spawn in late spring to early summer. Males intercept females at spawning beaches as they come ashore to spawn. Photo courtesy of Jane Brockman Larvae hatch in 2 to 4 weeks. Male Female Females dig a nest in sand and deposit eggs. Males the fertilize eggs. Females may spawn multiple times laying up to 80,000 eggs. Eggs develop in a nest on a beach.

3 Development Juveniles live & forage in mud at low tide Photo: E Hogan molts and 9-10 years to become adults Molting juvenile Limulus Slide courtesy of Jane Brockman 3

4 The Resource: Shorebirds At least 11 species of shorebirds feed on horseshoe crab eggs in Delaware Bay during the final legs of their northward migration. Slaughter Beach, DE Horseshoe crab eggs are an important source of food in Delaware Bay where there are high surface densities of eggs on the beaches. They provide essential energy and are important to the survival and reproduction of shorebirds. Photo: K. Tuxbury

5 The Resource: Ecotourism Over 1 million shorebirds converge on Delaware Bay each spring. Thousands of tourists visit the Bay to watch the horseshoe crab spawning/shorebird phenomena. Ecotourism related to horseshoe crabs provides millions of dollars annually Virginia: $108 million New Jersey: $87.5 million Maryland: $83 million Delaware: $11.5 million

6 The Resource: Biomedical Industry Limulus Amebocyte Lysate (LAL), a biochemical constituent, is produced from horseshoe crab blood. o LAL detects bacterial pyrogens fever causing endotoxins that are pathogenic to humans; o LAL is the standard test used to screen all medical equipment that comes in contact with blood or spinal fluid; o New applications include detection of bacterially contaminated food ml of animal s blood is taken via cardiac sinus puncture (total blood volume is ml). ~30% mortality rate associated with bleeding and handling stress. FDA mandates that bled crabs be returned to where they were captured within 72 hrs (new MA regulations allow bled crabs to be sold for bait). Multimillion dollar industry (LAL can cost upwards of $5,000 per quart) Annual revenues $60 million. Four LAL producing companies in US. One on Cape Cod, three in Delaware Bay area.

7 The Resource: Fertilizer & Animal Feed Commercial fisheries for fertilizer & animal feed 1850 s to 1950 s Peak harvests in Delaware Bay - 4 million crabs annually (1870 s & 1920 s to 1930 s) Harvests declined to 100,000 crabs by the 1950 s Decline due to: -Declining catches - Competition with commercial fertilizers - Public health concern Between 1950 to 1980 under reduced fishing pressure spawning populations slowly recovered

8 The Resource: Bait Fishery Commercial Fishery for Bait 1980 s to present Bait for American eel and whelk (conch) Eel fishery targets egg-bearing females 1990 s the commercial fishery increased dramatically mostly in the Mid-Atlantic but also in New England Fishery has historically lacked coordinated, coast-wide monitoring, and regulation Coast-wide landings have reached levels attained during fertilizer and animal feed fishery Whelk American eel

9 Fishery Regulations Prior to 1998 STATE DC, CT, GA, ME, NC, PA, Federal waters RI, MA, NY, FL VA NJ NH DE MD SC REGULATIONS No harvest regulations, no reporting No harvest regulations; no reporting; license required License required; no limit; trawling & dredging prohibited Reporting & license required; no limit; Delaware Bay only hand harvesting allowed Reporting & license required; 10 crabs/day/person Reporting & license; seasonal closures; vessel limit of 1500/day Reporting & license required; annual quota 750,000 lbs; seasonal closures; 25 crabs/day/person Reporting & license required; harvest limited to biomedical, scientific & educational purposes; minimum crab size & gear requirements

10 Atlantic States Marine Fisheries Commission (ASMFC) Management Concerns 1. Horseshoe crab populations declined under heavy harvesting from Harvesting levels for eel & whelk bait in 1990 s were similar to those during fertilizer & animal feed fishery. 2. Crabs are easily harvested with minimum of financial investment. This makes them susceptible to over-harvesting. 3. Long maturation rates (9-10 yrs) creates a lag for population recovery. 4. Population data (trawl & spawning surveys, egg counts) existing prior to 1998 lacked standardization and were of little informative value. 5. No regulations in many of the states where they are harvested.

11 ASMFC Mandatory Compliance Interstate Fishery Management Plan for Horseshoe Crab (ASMFC 1998) Regulations for commercial fisheries (bait & biomedical harvests) Monitoring programs Law enforcement to implement regulations Annual reports on fishery Reduce 2000 bait landings by 25% below levels (MA, RI, CT, NY, NJ, DE, MD) The National Park Service has supported research ( ) to survey spawning horseshoe crabs and investigate movement patterns. at several coastal parks (Cape Cod NS (MA), Fire Island NS (NY), Gateway NRA (NY) & Sagamore Hill NHS (NY). At the same time, other agencies (Fish & Wildlife Service, MA Div. Marine Fisheries, MA Audubon) also started monitoring programs.

12 Cape Cod NS Pleasant Bay Monomoy NWR Department of the Interior (USFWS & NPS) & the Lawsuit Horseshoe crabs had been harvested for biomedical uses & bait on Cape Cod (MA) within Pleasant Bay & Monomoy NWR since the 1970 s The Department of Interior (Cape Cod NS & Monomoy NWR) re-evaluated their position on the horseshoe crab harvest within their boundaries Cape Cod NS & Monomoy NWR closed their waters to horseshoe crab fishing Department of Interior was sued by biomedical harvester & biomedical company (Associates of Cape Cod). But why did the Department of Interior stop the harvest...

13 Federal Regulation Regulation 36 CFR* Shellfishing by permit from the appropriate town is permitted in accordance with applicable Federal, State, and local laws. Regulation 36 CFR Prohibits the taking of wildlife except as authorized by hunting. Prohibits feeding, touching, teasing, frightening or intentional disturbing of wildlife nesting or breeding. Prohibits possessing unlawfully taken wildlife or portions thereof. Authorities and Exceptions Commercial Activities: Engaging in or soliciting any business in park areas, except in accordance with provisions of a permit, is prohibited. Research: A specimen collection permit may be issued if: Official Representative of scientific organization or educational institute; For purpose of research, monitoring; Only to meet park management goals. *CFR: Code of Federal Regulations

14 I m not a fish or What shellfish I am am wildlife! I? Is a horseshoe crab fish or shellfish? Photo: C. Roman Taxonomy Kingdom: Animalia, Phylum: Arthropoda, Subphylum: Cheilcerata, Class: Merostomata, Order: Xiphosurida, Family: Limulidae, Genus: Limulus, Species: polyphemus Technically horseshoe crabs are neither fish, shellfish, or crustacean (Class Crustacea) they are more closely related to spiders and scorpions than true crabs. Massachusetts Definition of Shellfish & Fish M.G.L. Chapter 130: Defines Shellfish' as clams, conchs, limpets, mussels, oysters, periwinkles, quahaugs, razor clams or razor fish, scallops, sea clams, sea quahaugs, sea scallops and winkles. Defines Fish'', any animal life inhabiting the ocean or its connecting waters including any crustacean or marine fish, whether free swimming or free moving, and any shellfish or sea worms, whether or not imbedded in the soil. All provisions of the chapter relative to fish shall, so far as apt, apply also to lobster meat and crab meat after the same has been taken from the shell. Federal definition for Wildlife Wildlife means any member of the animal kingdom and includes a part product except fish. Fish means any member of the subclasses Agnatha, Chondrichthyes or Osteichthyes or any mollusk or crustacean found in saltwater.

15 Horseshoe Crab Research At Coastal National Parks Funded ( , , ) by the National Park Service MA Sagamore Hill NHS NJ Cape Cod Bay Nauset Estuary Monomoy NWR Pleasant Bay CT NY Gateway NRA (Jamaica Bay unit) Cape Cod NS Fire Island NS (Great South Bay) Atlantic Ocean Photo: J. Balliett Spawning surveys conducted on Cape Cod (2000 to 2010); and at Long Island NPS units ( ) in collaboration with other agencies. Traditional tagging & acoustic telemetry were used to determine movement patterns of crabs in Nauset Estuary, Pleasant Bay (Cape Cod, MA), Great South Bay (NY) & Jamaica Bay (NY)

16 US Fish & Wildlife Cooperative Tagging Program Female crab Measure prosomal (carapace) width Male crab Record sex Attach tag with a unique tag number, record date and tagging location Re-sighted tagged crab at Fire Island NS When a tagged horseshoe crab is seen, the public can report the tag number either online or call the toll-free number: LIMULUS Pewter reward pin

17 Beach Surveys Spawning surveys are done during the full and new moon high tides in May & June, during the day & at night. Data collected includes number of spawning crabs (by sex), cluster size (number of crabs in a cluster), and single crabs. The time and length of the surveys are standardized so an Index of Spawning Activity (ISA) can be calculated.

18 Mean egg abundance Spawning Index Pickering Beach, DE Spawning & Egg Densities In Delaware Bay large congregations of spawning crabs are common. Egg densities are high. Photo: Jane Brockman In Southern New England spawning indices and egg densities are much lower. 1 Spawning Index (# females m -2 ) Talisman Beach, Fire Island, NY Cape Cod Long Island, NY Jamaica Bay,NY Delaware South Carolina Pleasant Bay, MA Egg Density Deep sediments (5-20cm) Surface sediments (0-5cm) Cape Cod Long Island, NY Jamacia Bay, NY Delaware

19 Percent female Cape Cod Bay Nauset Estuary Pleasant Bay Monomoy NWR CT NY Jamaica Bay Cape Cod NS Talisman Atlantic Ocean Site Spawning Sex Ratios (the ratio of females to males on spawning beaches) Historic (1950 s) 2000 to 2002 Recent ( ) Cape Cod Bay (MA) 1 to to 2.9 1: 1.7 Monomoy NWR (MA) -- 1 to 1.9 1: 1.8 Nauset Estuary (MA) -- 1 to 1.6 1: 1.3 Pleasant Bay (MA) 1 to to 5.8 1: 8.1 Jamaica Bay (Brooklyn, NY) : 3.8 Talisman (Fire Island, NY) : Percent females on spawning beaches at other Cape Cod areas Pleasant Bay (MA) has highly male skewed sex ratios Other Cape Cod sites have sex ratios of 1 female to 1-3 males Delaware Bay, Long Island spawning sex ratios are 1 female to 2-4 males Unharvested populations (ME, FL) are 1 female to 2 males 0 Historic, 1950s

20 Tagging In Pleasant Bay, MA Evidence for a localized population Percent of recaptures 2027 crabs tagged in Pleasant Bay by URI/NPS in % overall recapture rate; 12% live recapture rate (324 tags re-sighted). 88% of recaptures found within 2.5km of original tagging location. All recaptures, except 1, were observed in Pleasant Bay. No crabs tagged in other areas (Monomoy NWR, Cape Cod Bay) have been reported as recaptured in Pleasant Bay Pleasant Bay Recaptures Photo: K. Medeiros Same site Less 2.5km greater 2.5km Same site Less 2.5km greater 2.5km Photo: K. Medeiros Recaptured in same year Recaptured in subsequent years

21 Tracking crabs underwater with acoustic telemetry Sonar tracking tag on crab Transmitter emits a unique acoustic signal; Crabs tracked using a hydrophone and continuously tracked with Submersible Ultrasonic Receivers (SUR); Transmitters can be detected up to 500m (about 1/3 of a mile) detection in shallow water is ~50-100m; SURs scan for signals at 1-2 min intervals and store data; Some crabs also tagged with continuous depth & temperature data logger tags; All crabs tagged with US Fish & Wildlife button tags. Listening for sonar signals in Pleasant Bay SUR buoy Sonar tracking tag & button tag on crab

22 Impact of Biomedical Bleeding on Horseshoe Crab Movement and Physiology Rate of movement (m min -1 + SE) Tracked bled and unbled crabs with acoustic telemetry in summer 2001: Bled crabs had a random movement patterns (disoriented behavior). Control crabs had directional movement patterns. No difference in rate of movement, but trend for bled crabs to move slower. Evidence from another bleeding study indicates protein concentration of hemolymph (blood) remains significantly lower in bled and handled crabs than in unbled control crabs. 5 Bled crabs Control crabs No detections Bled Control

23 Crab # 128 Horseshoe Crab Movement In Pleasant Bay Released Last detection Crab # 127 Released May 2009 June 2010 Released May 2009 Aug 2009 April 2010 June 2009 June 2009 Sept-Oct 2009 Oct-Dec 2009 July-Sept 2009 Sept 2009 Location of SURs (Submersible Ultrasonic Receivers)

24 Crab # 156 Released May 2009 Horseshoe Crab Movement In Pleasant Bay May-June 2010 Released Last detection Crab # 162 Released May 2009 April 2010 May 2010 June 2009 June 2009 Oct-Nov 2009 Aug 2009 Oct-Dec 2009 May 2010 June 2010 July 2009 Sept 2009 Location of SURs (Submersible Ultrasonic Receivers)

25 Horseshoe Crab Movement In Pleasant Bay Crab # 110 Released Last detection Crab # 155 Released May 2009 Released May 2008 May 2010 July 2009 June 2010 Nov 2009 June 2008 May 2010 Aug 2010 July 2010 Aug 2009 Oct 2009 Aug 2010 Aug 2009 Sept 2009 Location of SURs (Submersible Ultrasonic Receivers)

26 25-Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May-10 Depth (m) Temperature C Depth-temperature & telemetry data for crab #134 Crab overwintered in Pleasant Bay F. Found dead on spawning beach 29 May 2010 C D E B F A A: Tagged Marsh May 2009 B: E Hog Is. 7 July 2009 C: Lower Pleasant Bay 23 Sept-7 Oct 2009 Temperature E: Pochet Inlet 23 & 29 May 2010 D: W Hog Is. 19 May 2010 Depth Full moon New moon C: Lower Pleasant Bay 21 Nov 2009 C: Lower Pleasant Bay 24 April-2 May SURs out of water for winter James-Pirri, M.-J Seasonal movement of the American horseshoe crab (Limulus polyphemus) in a semi-enclosed bay on Cape Cod, Massachusetts (USA) as determined by acoustic telemetry. Current Zoology 56: (invited paper, special issue on horseshoe crab behavior).

27 Important Research Findings Related to Resource Management Biomedical bleeding may alter normal behavior and may long lasting (several weeks) impacts on physiology. Spawning hot spots Three beaches (two of them in Pleasant Bay) represented 57% of total spawning on Cape Cod. Evidence from Long Island also indicates spawning hot spots. Spawning sex ratios are skewed in Pleasant Bay Historical (1950 s) sex ratios were lower (1:2.5 female to male) compared to ratios observed over past 10 years, and are different from other areas of Cape Cod. Possibly related to the long history of harvest in the bay. Evidence for localized populations on Cape Cod Sex ratios differed among regions High percentage of crabs recaptured at or near (within 2km) of original tag location Evidence for spawning site fidelity Little movement among bays Crabs overwinter in Pleasant Bay This may be the model for SE New England populations in semi-enclosed Bays (Great Bay, NH; Pleasant Bay, MA) Localized populations require different management techniques to maintain sustainable populations (regional vs. local stocks).

28 Thanks! National Park Service Cape Cod NS, Sagamore Hill NHS, Fire Island NS, Gateway NRA NPS Park and Regional staff NPS Bio Technicians Student Conservation Association Interns The many volunteers and others who helped

29 Questions?

30 The Lawsuit a timeline 1999 Cape Cod NS & Monomoy NWR (Dept. of Interior- DOI) made aware of illegal harvesting of horseshoe crabs (spring) Fishery is closed & active protection of horseshoe crab as a wildlife species is implemented in federal waters (spring) DOI is sued by biomedical harvester & biomedical company (Associates of Cape Cod, ACC) over fishery closure Court injunction allows biomedical harvester to collect crabs in federal waters Courts rule in favor of the DOI (horseshoe crabs are wildlife), fishery closure within NPS was legal. ACC withdrawals lawsuit. But Monomoy NWR had unresolved issues regarding authenticity of their boundaries. Court injunction allows biomedical harvester to harvest crabs within USFWS Refuge Biomedical harvester appeals decision in Superior Court, but it is sent back to District Court because of Monomoy NWR s boundary issues to Monomy NWR resolved boundary issues. Fishery remains closed in federal waters State closes Pleasant Bay to bait harvest, biomedical harvest still allowed in nonfederal waters MA instituted more conservative regulations - harvest prohibited during peak spawning, minimum size limits. Present Federal waters closed to harvest, Pleasant Bay closed to bait harvest, biomedical harvest is allowed in non-federal waters.

31 Passive Acoustic Telemetry Number of transmitter detections over time 91% of crabs detected, ~58,000 detections, 922 crab-days or daily detections Percent of daily detections Spawning 2009 (May-June) 31 crabs detected <10% Post-spawning 2009 (July-August) 35 crabs detected 10-20% 20-30% <30% Fall 2009 Sept-Dec 23 crabs detected X Number of crabs Spawning 2010 (Late-April-June) 26 crabs detected

32 But Some horseshoe crabs do move out of the Bay Crab #78: Stayed in upper bay in June, 2008 Passed into lower bay on June 30, 2008 Recaptured by trawler on July 21, 2008