Researchers try to duplicate production success using alternate red king crab stock

Transcription

1 AKCRRAB News Flash, January 2011 Alaska Sea Grant January 2011 Researchers try to duplicate production success using alternate red king crab stock Large-scale red king crab (Paralithodes camtschaticus) larval culture conducted at the Alutiiq Pride Shellfish Hatchery from 2007 to 2010 has been increasingly successful. In 2009 and 2010 researchers achieved over 50% survival to the glaucothoe stage and 20% to the first juvenile stage, producing over 100,000 first stage juveniles in each year. This large-scale production success is based on hatchery rearing of Bristol Bay red king crabs. It is unclear if alternate stocks will have similar success. Female red king crab caught in the Juneau area. Courtesy of Jim Swingle. Experiments in 2011 will compare larval rearing success between broodstock collected in Bristol Bay and Juneau using identical conditions to determine if broodstock origin influences success of hatchery production. Preliminary genetic results suggest genetic differences between these two stocks. Twenty egg-bearing female red king crabs were collected in the Juneau area during Alaska Department of Fish and Game crab surveys, and an additional twenty females were collected from Bristol Bay by commercial fishing vessel FV Stormbird, owned by Lu Dochtermann and skippered by Gene LeDoux. These crabs are currently in Seward and are expected to hatch their larvae in spring. Based on previous observations, researchers expect Bristol Bay crabs to release their larvae in March, with release by Juneau crabs then or possibly earlier. Researchers are optimistic that similar success seen with Bristol Bay crabs will be achieved using Juneau stocks. AKCRRAB thanks Lu Dochtermann and ADFG for collecting crabs in fall :50:56 PM]

2 AKCRRAB News Flash, January 2011 Alaska Sea Grant 3:50:56 PM]

3 AKCRRAB News Flash, February 2011 Alaska Sea Grant February 2011 AKCRRAB conducts juvenile red king crab tagging study AKCRRAB biologists are developing methods to identify hatchery-raised king crab using physical tags. Their experiments test crab survival and retention of tags after molting for a range of juvenile crab sizes. The methods are modeled after similar efforts in Chesapeake blue crab. From October 2010 to February 2011, Alaska Sea Grant research biologist Jim Swingle conducted a tagging study using coded wire tags, visible implant elastomers, and dactyl clipping on juvenile red king crab. Each method was tested on three different size classes of juveniles (5, 10, and 15 mm carapace width) to determine the Juvenile red king crab with orange elastomer tag. Courtesy of Jim Swingle. minimum size juveniles could be effectively tagged. The experiment was run until all tagged juveniles molted at least once, so that tag retention could be measured post-molt. The findings suggest that juveniles of 10 mm CW and larger can be marked with low levels of mortality and high post-molt tag retention rates using both coded wire tags and visible implant elastomers. The mark from dactyl clipping was lost. Because the elastomers are likely to become more difficult to detect as the animals increase in size and their shells become increasingly opaque, the coded wire tags are more likely detectable over the lifetime of the animal. The experiment was conducted at the University of Alaska Fairbanks Lena Point facility in Juneau, Alaska, using juvenile crabs reared at the Alutiiq Pride Shellfish Hatchery during 2010 production experiments. These tagging methods should prove useful to researchers and resource managers interested in further exploring the feasibility and effects of a king crab stock rehabilitation program. 3:50:35 PM]

4 AKCRRAB News Flash, February 2011 Alaska Sea Grant 3:50:35 PM]

5 AKCRRAB News Flash, March 2011 Alaska Sea Grant March 2011 High school student presents red king crab research at science fair and is selected for national competition Lia Domke, a senior at Juneau Douglas High School, conducted red king crab research under the guidance of Dr. Sherry Tamone of the University of Alaska Southeast. Domke's study titled "The effect of methyl farnesoate on the molting biology of juvenile red king crab (Paralithodes camtchaticus)" was presented at the Southeast Alaska Regional Science Fair on March and was selected as one of the best at the fair. Lia used crabs that were cultured at the Alutiiq Pride Shellfish Hatchery as a part of the AKCRRAB project. She won several awards, including Juvenile red king crab used in Lia Domke's study. an Audubon Society award, an Alaska Department of Fish and Game award focused on commercial fisheries, an American Chemical Society award, and the Coeur Alaska award for presenting a science fair project for three consecutive years. Her study will advance to the Intel International Science and Engineering Fair (Intel ISEF) held in Los Angeles May 8 13, :50:16 PM]

6 AKCRRAB News Flash, April 2011 Alaska Sea Grant April 2011 Production of red and blue king crab at Alutiiq Pride Shellfish Hatchery Larval rearing is well under way at the Alutiiq Pride Shellfish Hatchery as red and blue king crabs release their larvae. St. Matthew Island blue king crabs were the first to hatch larvae, which are being reared in large-scale tanks to investigate temperature effects on survival and rearing duration. The ovigerous female blue king crabs were collected off St. Matthew Island in the commercial fishery by the F/V Destination. Red king crabs from Bristol Bay and southeast Alaska are being reared at the hatchery to determine if broodstock origin impacts hatchery production success. Previous Adult female blue king crab. Carapace width is 15 cm, and weight is 2 kg. hatchery success was achieved using red king crabs from Bristol Bay, and biologists are eager to duplicate that success with different stocks. The F/V Stormbird collected the Bristol Bay crabs in the commercial fishery, while southeast Alaska crabs were obtained by the Alaska Department of Fish and Game during the fall crab survey. Biologists are hopeful that similar production success can be achieved with the southeast Alaska crabs. Biologists hope to improve on previous experiments and refine hatchery protocols to maximize production. When blue king crabs reach the juvenile stage, a nursery rearing experiment will test the effects of diet and density on growth and survival. King crab juveniles produced at the hatchery will be used in experiments by NOAA and University of Alaska Fairbanks researchers to better understand early juvenile king crab biology. 3:49:50 PM]

7 AKCRRAB News Flash, April 2011 Alaska Sea Grant 3:49:50 PM]

8 AKCRRAB News Flash, May 2011 Alaska Sea Grant May 2011 Biologists culture southeast Alaska red king crab at Alutiiq Pride Shellfish Hatchery Alaska Sea Grant biologists have successfully cultured red king crab larvae from females collected in southeast Alaska. Previous success was achieved using red king crabs from Bristol Bay, and this experiment aimed to determine if broodstock origin impacts hatchery production success. Culturing protocols developed for Bristol Bay crabs were applied to larvae from southeast Alaska broodstock. Survival from stocking to the postlarval (glaucothoe) stage was 43% for Bristol Bay crabs and 60% for southeast Alaska crabs. The improved Southeast Alaska red king crab glaucothoe. survival of the southeast Alaska crabs suggests that hatchery protocols for rearing red king crabs can be applied to stocks outside Bristol Bay. This is an important finding as future stock enhancement programs may require broodstock from specific areas that are targeted for releases. The ability to culture crabs from different locations is critical for statewide enhancement. In this effort, we took broodstock from southeast Alaska, which is not currently a target for enhancement, so that we might use the resulting juvenile crabs in summer field studies to evaluate predation effects on hatchery-cultured juveniles. Juvenile red king crabs cultured at the hatchery will also be used in laboratory experiments at the NOAA Alaska Fisheries Science Center Behavioral Ecology Lab in Newport, Oregon, to better understand early juvenile king crab biology. 3:49:24 PM]

9 AKCRRAB News Flash, May 2011 Alaska Sea Grant 3:49:24 PM]

10 AKCRRAB News Flash, June 2011 Alaska Sea Grant June 2011 AKCRRAB ships juvenile red king crabs to Juneau Ultimately, the success of a fishery rehabilitation effort for Alaska king crabs will hinge on the ability of released hatchery-reared individuals to be competent able to compete for resources, find shelter, and avoid predation. AKCRRAB scientists at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences are increasing their research into factors that may affect competency of hatchery-raised juveniles in the wild. In June 2011, researchers shipped 4,400 juvenile red king crabs from the Alutiiq Pride Shellfish Hatchery in Seward Juvenile red king crab (1.8 mm carapace width). to the Juneau Center of the UAF School of Fisheries and Ocean Sciences. The juveniles were hatched and reared from ovigerous females collected in the Juneau area during the Alaska Department of Fish and Game 2010 fall crab survey. The juvenile crabs are being returned to Juneau for field experiments, to develop successful release strategies and improve understanding of potential environmental impacts of releasing hatchery-cultured crabs into the wild. Little is currently known about predation on newly settled red king crabs, but predation is expected to be a major factor in post-release survival. Experiments using scuba and underwater video cameras will determine if body size or seasonal differences in release time impact predation rates, helping to identify the time periods and sizes at which juvenile crabs may be most vulnerable. 3:48:59 PM]

11 AKCRRAB News Flash, June 2011 Alaska Sea Grant 3:48:59 PM]

12 AKCRRAB News Flash, July 2011 Alaska Sea Grant July 2011 Undergraduate researcher compares growth of juvenile red and blue king crabs Jaspri Sylvan completed her freshman year at Brown University and returned to her hometown to assist Miranda Westphal, fisheries graduate student at the University of Alaska Fairbanks, Juneau Center. Sylvan hopes to learn how growth patterns vary in juvenile blue and red king crabs. This is of interest because red king crabs have moved into areas previously occupied by blue king crabs in the Pribilof Islands, and interactions between the two species may limit recovery of blue king crabs. Crabs were cultured at the Alutiiq Pride Shellfish Hatchery in 2008 and 2009 and shipped to Juneau as recently settled instars. Westphal reared both species individually Two-year-old juvenile blue (left) and red (right) king crabs reared under identical conditions. Photo by Ben Daly. under identical laboratory conditions and photographed each molt, and Sylvan is analyzing the blue king crab photos. Results suggest that juvenile red king crabs are much larger than blue king crabs of the same age two-year-old juvenile red king crabs are about 49 mm carapace width, while blue king crabs are about 18 mm carapace width. Thus, blue king crabs of the same age might be vulnerable to red king crab predation. Sylvan has been involved with AKCRRAB research for the past three years. Her plans include attending graduate school and conducting research in Alaska. Future AKCRRAB studies will examine interactions between red and blue king crabs, which may be important to population recovery and potential restoration efforts. 3:48:32 PM]

13 AKCRRAB News Flash, July 2011 Alaska Sea Grant 3:48:32 PM]

14 AKCRRAB News Flash, August 2011 Alaska Sea Grant August 2011 Undergraduate student assists in field study investigating juvenile red king crab predation Tim White of the University of California Los Angeles is participating in the Research Experience for Undergraduate (REU) program, funded by the National Science Foundation and hosted at the University of Alaska Southeast. The REU program allows undergraduates to do research during the summer to gain experience and refine their interests. White is assisting Ben Daly, fisheries graduate student at the University of Alaska Fairbanks, Juneau Center, in a field study that will help develop successful release strategies and improve understanding of Tim White at experiment site. Photo by Ben Daly. potential environmental impacts of releasing hatchery-cultured crabs into the wild. Little is known about predation on newly settled red king crabs, but predation is expected to be a major factor in post-release survival. Age-0 red king crabs cultured at the Alutiiq Pride Shellfish Hatchery in Seward are being tethered for 24-hour trials in southern Lynn Canal near Juneau. Scuba and underwater video cameras are used to assess survival and interactions with predators. Results will determine if body size or seasonal differences in release time impact predation rates. White is majoring in marine biology at UCLA and has been involved in research in Tahiti investigating effects of nutrient limitation on growth of macroalgae. He is entering his senior year of college, and plans to attend graduate school in the future. 3:48:10 PM]

15 AKCRRAB News Flash, August 2011 Alaska Sea Grant 3:48:10 PM]

16 AKCRRAB News Flash, September 2011 Alaska Sea Grant September 2011 AKCRRAB reports research progress to fishing industry AKCRRAB scientists and Steering Committee representatives presented information on the AKCRRAB program to the crab industry at the Bering Sea Crab Science Symposium IV, hosted by Alaska Bering Sea Crabbers at the Leif Erikson Lodge in Seattle, August 24, Heather McCarty and Dr. David Christie gave an introduction to the AKCRRAB program, and Jeff Hetrick provided an overview of culturing methodologies at the Alutiiq Pride Shellfish Hatchery. Dr. Ginny Eckert described advances in king crab biology on growth, life history, habitat, and predation studies at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences, while Dr. David Tallmon provided results from the Red king crab juvenile (~1 year old, ~15 mm carapace length) in the wild in Juneau, June Photo by G.L. Eckert. University of Alaska Southeast on king crab genetic structure and genetic considerations for enhancement. Dr. Bob Foy outlined research projects under way at the National Marine Fisheries Service Kodiak lab on king crab habitat, culturing technologies, and ocean acidification. Sue Aspelund and Ron Josephson summarized the process that Alaska Department of Fish and Game is developing, to regulate shellfish/invertebrate enhancement projects. The presentations were well received, and participants indicated their interest to continue support for AKCRRAB-related research. Presentations are available on the Alaska Sea Grant website. 3:47:38 PM]

17 AKCRRAB News Flash, September 2011 Alaska Sea Grant 3:47:38 PM]

18 AKCRRAB News Flash, October 2011 Alaska Sea Grant October 2011 Researchers at NOAA Alaska Fisheries Science Center in Kodiak examine red king crab cannibalism Red king crabs are highly cannibalistic, which is a problem for mass culture and may reduce post-release survival. During the last two summers Jessica Popp and Laura Whitefleet-Smith, undergraduate recipients of the NOAA Hollings Scholarship, conducted experiments to reveal how predator size affects predation at different prey densities and in different habitats. They were mentored by Dr. Chris Long and Kathy Swiney at the NOAA AFSC Kodiak Lab. Predators (age-1 and age-2 red king crabs) and prey (young-of-the-year red king crabs) at a range of densities An age-1 red king crab hunts for younger crabs in an experimental container. Photo courtesy of NOAA Fisheries. (2, 5, 10, 18, 25, 35, 50 crabs per tank) were placed in containers with habitats of different structural complexities (bare sand, sand with shell hash, sand with shell, algal mimic). In low structure habitats (bare sand, sand with shell hash), proportional predation by age-1 crabs was greater at low prey densities, while age-2 crabs consumed almost all the prey at all densities. In high structure habitats (sand with shell, algal mimics) proportional predation by age-1 crabs was reduced at all prey densities, while predation rates by age-2 crabs increased with prey density. Results indicate that habitat complexity reduces predation, and suggest that releases should target habitats with complex structure at low densities (i.e., fewer than 30 crabs per m 2 ). Also, stocking in alternate years in a given area may minimize cannibalism among year classes. 3:47:08 PM]

19 AKCRRAB News Flash, October 2011 Alaska Sea Grant 3:47:08 PM]

20 AKCRRAB News Flash, November 2011 Alaska Sea Grant November 2011 Blue king crab rearing yields high survival at Alutiiq Pride Shellfish Hatchery Juvenile blue king crabs had an 85% survival after a 10 week nursery grow-out period at the Alutiiq Pride Shellfish Hatchery in Seward. The blue king crab larvae were hatched from ovigerous females collected in the commercial fishery off St. Matthew Island, and were reared to the first juvenile stage at NOAA Fisheries in Kodiak. The juveniles were then shipped to Seward and reared at a density of 200 crabs per square meter a low density compared to previous years. With identical diet and temperature, juvenile blue king crab rearing in 2008 yielded 50% survival at a density of 1,300 crabs per Juvenile blue king crab, about 3 mm carapace width. Courtesy Jim Swingle. square meter for seven weeks. Juvenile red king crabs reared at the hatchery from 2008 to 2010 at higher densities had even lower survival. For example, red king crabs reared at 4,000 crabs per square meter had 21% survival after eight weeks. Stocking density undoubtedly has strong effects on hatchery survival. Future studies are needed to determine what combination of survival rate and density could maximize production per unit effort for blue king crab, especially when considering floor space and cost of pumping, filtering, and heating seawater. 3:46:05 PM]

21 AKCRRAB News Flash, November 2011 Alaska Sea Grant 3:46:05 PM]

22 AKCRRAB News Flash, December 2011 Alaska Sea Grant December 2011 Blue king crab broodstock arrive from St. Matthew Island Ovigerous female blue king crabs have arrived at the Alutiiq Pride Shellfish Hatchery in Seward. The commercial fishing vessel Seabrooke, owned by Scott Campbell Sr. and skippered by Scott Campbell Jr., collected the 19 crabs as an in-kind contribution to AKCRRAB. The crabs were caught near St. Matthew Island during the 2011 commercial fishery and delivered to Dutch Harbor, and then shipped to Seward. The small geographic range of blue king crab, hazardous weather, and limited shipping opportunities have made acquiring blue king crab broodstock difficult in previous years, Ovigerous (with eggs) female blue king crab. Courtesy of Ben Daly. which makes their successful delivery this year especially important. Blue king crab larvae have been more challenging to rear at the hatchery compared to the success of red king crab production, but AKCRRAB biologists are optimistic that conditions customized to blue king crabs will yield improved survival and growth rates in Blue king crab larvae are expected to hatch in winter/spring 2012 and will be used in large-scale experiments focused on improving culture techniques for larvae, glaucothoe, and juveniles. AKCRRAB biologists are excited to work with the St. Matthew blue king crabs and are looking forward to the 2012 production run. To hear an interview with Ben Daly about last month's News Flash story, go to 3:45:12 PM]

23 AKCRRAB News Flash, December 2011 Alaska Sea Grant 3:45:12 PM]