Progress 06/17/13 to 07/31/14
Outputs
Target Audience: Shellfish growers in SW Washington, Willapa Bay, Grays Harbor. State and federal regulatory agencies. Changes/Problems: State regulatory agencies had complex regulatory requirements that mandated additional amounts of fate and persistence and nontarget impact data that was well beyond the initial scope of this project. This required considerable additional expense and required several years of research to accommodate. What opportunities for training and professional development has the project provided? CO-PI attended regional and national shellfish grower research conferences. How have the results been disseminated to communities of interest? Field days, workshops, grower conferences and meetings, illustrated guide to shellfish. What do you plan to do during the next reporting period to accomplish the goals? The next phase of this project will require successfully implementing it into the grower management of Shellfish IPM practices and collecting large-scale nontarget impact and other data mandated by state regulatory agencies.
Impacts
What was accomplished under these goals?
Biological, mechanical and chemical alternatives for burrowing shrimp control were evaluated during the course of this project. After several years of research efforts, a chemistry, imidacloprid, was identified that provided efficacy at minimal environmental risk. Research to assess the non-target impacts and fate and persistence of this chemistry was done to help secure a federal registration for shrimp control. A risk assessment document and other registration support materials were provided to EPA to secure a federal registration. Additional research and documentation packages were provided to Washington Department of Ecology to secure an NPDES permit required for use of aquatic pesticides in the state of Washington. EPA issued a federal registration of imidacloprid for burrowing shrimp control in Willapa Bay in late summer 2013. Issuance of the NPDES by DOE is imminent, at which point the shellfish grower can begin implementing this alternative control for burrowing shrimp.
Publications
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Progress 06/17/13 to 09/30/13
Outputs
Target Audience: Shellfish growers in SW Washington, Willapa Bay, and Gray's Harbor. State and federal regulatory agencies, environmental interests. Changes/Problems: State regulatory agencies had complex regulatory requirements that mandated additional amounts of fate and persistence and nontarget impact data that was well beyond the initial scope of this project. This required considerable additional expense and required several years of research to accommodate. What opportunities for training and professional development has the project provided? Two Master's Theses andone PhD Thesis were written based on this research. Co-PI attended regional and national shellfish grower research conference. How have the results been disseminated to communities of interest? Communication with growers and with state and federal agencies has been integral to the registration process. In general, this has been through technical reports, direct communication,field days, workshops, grower conferences and meetings, and an illustrated guide to shellfish. What do you plan to do during the next reporting period to accomplish the goals? From the WSU research perspective, there does not appear to be a large research agenda although there may be additional information needed to obtain state level (Department of Ecology) registration. The next phase of this project will require successfully implementing it into the grower management of Shellfish IPM practices and collecting large-scale nontarget impact and other data mandated by state regulatory agencies.
Impacts
What was accomplished under these goals?
The oyster industry in the PNW lost its only control for burrowing shrimp, Sevin, in 2012. Without a viable alternative to this control (Sevin), this $60 million/yr industry would cease to exist within a few decades. This project was a collaborative research project to develop and test alternative mechanical, biological and chemical controls of burrowing shrimp. One chemical, imidacloprid, proved to be the only viable solution, and its registration for use in controlling burrowing shrimp in the Willapa Bay and Grays Harbor estuaries was secured in 2013. It commercial use is expected in 2014. As a consequence, the permanent loss of the shellfish industry because of its major pest, burrowing shrimp, is no longer a significant industry concern. Biological, mechanical and chemical alternatives for burrowing shrimp control were evaluated during the course of this project. After several years of research efforts, a chemistry, imidacloprid, was identified that provided efficacy at minimal environmental risk. Research to assess the non-target impacts and fate and persistence of this chemistry was done to help secure a federal registration for shrimp control. Compared to carbaryl, imidacloprid has substantially less (>1000 fold) off-target toxicity. A risk assessment document and other registration support materials were provided to EPA to secure a federal registration. Additional research and documentation packages were provided to Washington Department of Ecology to secure an NPDES permit required for use of aquatic pesticides in the state of Washington. EPA issued a federal registration of imidacloprid for burrowing shrimp control in Willapa Bay in late summer 2013. Issuance of the NPDES by DOE is imminent, at which point the shellfish grower can begin implementing this alternative control for burrowing shrimp.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2013
Citation:
Frew J. 2013. Environmental and Systemic Exposure Assessment for
Green Sturgeon Following Application of Imidacloprid to Control Burrowing Shrimp in Willapa Bay, WA. PhD Thesis, University of Washington.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Moore J., N. Haldeman, K. Patten. Burrowing Shrimp Recruitment Monitoring of Critical Shellfish Production Areas of Willapa Bay. 2013. Proceedings, PCSGA 2013 meetings. Pacific Shellfish Growers conference.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Patten, K.D. (2013). Burrowing Shrimp IPM with Imidacloprid - A) Management of New Recruits and B) Improving Control in Sites with Dense Eelgrass. Proceeding - Pacific Shellfish Growers Association 2013 Conference.
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Progress 01/01/12 to 12/31/12
Outputs
OUTPUTS: Our group is trying to get imidacloprid certified by USEPA and the Washington Department of Ecology (WADOE) for use on burrowing shrimp in order to protect oyster cultivation in Willapa Bay and Gray's Harbor, Washington state. The compound is not as effective as carbaryl, using currently available protocols but has much lower toxicity to non-target organisms. Studies underway include additional tests of non-target organism toxicity and of persistence. PARTICIPANTS: Kim Patten, Alan Schreiber TARGET AUDIENCES: Shellfish growers, coastal environmentalists PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Carbaryl is being phased out as a control agent for burrowing shrimp and the search for a replacement has resulted in a neonicotinoid pesticide known for its relative specificity to arthropods. Many other compounds were tested but proved not suitable and many other procedures to eliminate the shrimp were tried, without success. Imidacloprid is the current best candidate for control of burrowing shrimp if it can receive registration for this use by the U.S. Environmental Protection Agency and WADOE
Publications
- No publications reported this period
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: Burrowing shrimp are a problem in the oyster industry because their burrows destabilize the substrate on which the oysters grow. A parasite has decreased mud shrimp populations but no comparable control exists for the ghost shrimp. Non-chemical methods of controlling ghost shrimp do not show much promise. Imidacloprid is the best candidate for a chemical alternative to carbaryl - its effective toxicity toward non-target species, like crab and fish, is of the order of a thousand fold less than carbaryl. Laboratory scale experiments indicated that the use of 0.5 lbs/ac would be effective but large-scale application carried out under an experimental use permit, suggested that this level was not adequate in certain terrain. Initial tests using a granular formulation suggest that this will work better. Plans are being formulated to obtain certification for imidacloprid application, to take advantage of its low toxicity toward non-target species. PARTICIPANTS: Kim Patten, Vince Hebert, Doug Walsh, Steve Booth, Steve Bollens, Chris Grue, Alan Schreiber, Dan Cheney, Chris Barker, Brett Dumbauld TARGET AUDIENCES: Oyster and other shellfish growers, federal and state regulatory agencies PROJECT MODIFICATIONS: As indicated above, the formulation of imidacloprid will need to be adjusted to get effective control in a greater number of estuary environments.
Impacts
The observation that 0.5 lb/ac imidacloprid does not effectively control the ghost shrimp in some estuary conditions has required additional testing to determine formulations that will be effective and leave acceptable levels of residue in the oyster meat. (The liquid leaves no residue so it is plausible that the granular formulation will also be acceptable.) Moving the chemical through the registration process will require additional data but imidicloprid appears to be effective against burrowing shrimp at concentrations much lower than are used for carbaryl and the data that it does not create major problems for other species appears to be solid, for species tested so far.
Publications
- No publications reported this period
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: The monitoring of pelagic and juvenile stages of shrimp and associated water quality variables in Willapa Bay was continued. There were seasonal and inter-annual variations in larval shrimp abundance, with peaks in summer of all years. There was also spatial variation in larval shrimp abundance, with peaks in the lower estuary, near Toke Point. There was near total absence of mud shrimp (Upogebia) larval detected. Ghost shrimp (Neotrypaea californiensis) larvae were present March-September, with peak abundance occurring in May. Abundances of Neotrypaea californiensis were highest during nocturnal ebb tides. Mapping the distribution of burrowing shrimp and their interaction with oyster aquaculture, sediment types, eelgrass beds in Willapa Bay was completed. The tideflats compromise 63% of the total bay. Within those tideflats 14% are populated with burrowing shrimp, 20% are in oyster production and 22% are occupied with eelgrass. Maximum age class of Neotrypaea and Upogebia was determined to be >10 years and 3 to 4 years, respectively. Ultrasound was investigated for its potential to control burrowing shrimp. It was successful in killing shrimp in the lab, but the power level required to cause death was high enough to be problematic for implementation in the field. Alternative methods to aerial applications of chemicals for burrowing shrimp control were evaluated. Several ultra-low volume spray systems showed promise, but subsurface spikewheel injection lacked consistent efficacy to be viable for the industry. A Federal EUP was obtained to evaluate large-scale application of imidacloprid for efficacy. Efficacy under these conditions was not consistent enough to satisfy the industry needs. Non-target impacts of imidacloprid to benthic invertebrates, commercial shellfish, crab and fish, compared to carbaryl, were very minor. IR4 trials indicated no imidacloprid residue in oyster meat at the 10x rate 90 days after application. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Alternative methods for control of the burgeoning populations of burrowing shrimp in Willapa Bay must be found in order to sustain the oyster farming operations in Willapa Bay. Ten percent of the human population in the county bordering the Bay depends on a livelihood from the aquaculture of oysters and clams. These studies elucidate several key component of shrimp biology, behavior and natural controls that can be integrated into a control program. In addition, we made significant progress toward the registration of an alternative insecticide, imidacloprid, which appears to have good efficacy and minimal non-target impact.
Publications
- Dumbauld, B.R., Holden, D., Langness, O. 2008. Do Sturgeon limit burrowing shrimp populations in Pacific Northwest estuaries Environmental Biology of Fishes.10.1007
- Smith, Andrew E. John W. Chapman, Brett R. Dumbauld. 2008. Population Structure and Energetics of the Bopyrid Isopod Parasite Orthione griffenis in Mud Shrimp Upogebia pugettensis Journal of Crustacean Biology 28(2):228-233.
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Progress 01/01/07 to 12/31/07
Outputs
A larval shrimp monitoring program was established to increase understanding of shrimp population dynamics and associated water quality in Willapa Bay. Neotrypaea californiensis larval were present March-September, with peak abundance in May and some inter-annual and tidal-cycle/diel-cycle variation. Seasonal patterns of salinity, as well as occasional low oxygen events, point to important interactions between Willapa Bay and the coastal ocean. Off-shore movement of larvae is from the northern edge of the range off the Canadian coast to southern edge off northern California. Populations at the edges were genetically distinct, but populations in Washington had similar profiles, so regional dispersal patterns could not be extrapolated. The distribution of burrowing shrimp and their interaction with oyster aquaculture, sediment types, eelgrass beds in Willapa Bay was mapped. Although a high percentage of ghost shrimp from different parts of the bay were infested with an
indigenous nematode, shrimp behavior or health appeared unaffected. A recently introduced parasitic bopyrid isopod, Orthione griffenis, has caused local extinctions of the mud shrimp, Upogebia pugettensis, but the indigenous bopyrid, Ione cornuta, parasitizes ghost shrimp at very low levels and is not impacting population size. Female isopods appear to produce pheromones that rapidly attract settling cryptoniscans (the pelagic stage), suggesting a potential control strategy via pheromone manipulation. Green and white sturgeon predation on burrowing shrimp was documented using stomach contents, feeding pit data, and exclosure experiments. Burrowing shrimp were 40-50% of the green sturgeon diet, but sturgeon longevity and scarcity limit their biological control potential. The effect of electroshock on ghost shrimp was examined in aquaria. 0.9-1V/cm AC caused shrimp to jerk and higher voltages caused temporary paralysis, but shrimp did not leave their burrows and recovered within a few
hours. Mortality occurred only at very large DC voltage. Suction and subsurface air bubbler harvest systems for adult shrimp were designed and evaluated; neither system appeared promising. Although commercial bait shrimpers may substantially suppress shrimp on non-producing beds, their tactics disrupt other control strategies. The shrimp industry would have to be substantially reorganized to integrate with the shellfish industry. Subsurface chemical delivery by spikewheel from a floating platform showed good potential, although topical applications were more effective, especially in beds with high eelgrass densities. The pathway towards registration of imidacloprid was pursued. Preliminary assessments of imidacloprid impact on benthic invertebrates, commercial shellfish, and fish was minimal to nil. Early life history impact on rainbow trout and sheepshead minnow were completed, also showing low LC50. IR4 residue trials at 90 days after treatment showed no contamination of oysters. An
application for a Federal Experimental Use Permit was submitted to the EPA and requirements for state permits were discussed with appropriate agencies.
Impacts
Alternative methods for control of the burgeoning populations of burrowing shrimp in Willapa Bay must be found in order to sustain the shellfish industries of Willapa Bay and Grays Harbor. These studies focused on further investigations of burrowing shrimp biology and ecology, as well as the potential of biological, mechanical, and chemical controls, with the goal of developing and implementing a fully integrated program. However, at this juncture, only imidacloprid shows the potential for implementation before a 2012 deadline. Significant progress has been made towards determining the appropriate use protocols and efforts to register the compound will continue.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Several pesticide chemistries were tested with subsurface application using a spikewheel injector system. Using this device, injection of imidacloprid was the most effective in controlling the shrimp. Additional trials were performed across a range of conditions, timings, and rates. The 0.4 lbs ai/ac rate of imidacloprid was the lowest effective rate across all sets of conditions. In contrast to broadcast applications, spikewheel applications were especially effective when a tidal flat was covered with eelgrass. Risk assessment of imidacloprid is now underway at the WSU Food and Environmental Quality Laboratory (FEQL). A high-volume waterjet sled and a deep penetrating harrow were evaluated as a mechanical method of shrimp control. Towing these implements from an oyster barge proved problematic and their efficacy was limited. Underwater subsurface shaking of high volumes of air as a means to remove and trap adult shrimp from their burrows did not work. With respect to
the electrofishing aspects of the project, the configuration of the electrical field necessary to kill the ghost shrimp was determined and laboratory trials are underway. The role of biologically based tactics for control of the shrimp is also being pursued. Nematodes and bopyrid isopods are being studied as natural controls of the shrimp populations. Shrimp populations across the bay were surveyed for nematode and the bopyrid isopod, Ione cornuta. There was considerable variation in the population of shrimp infested with nematode. Infestation with Ione, however, was uniform but very low (<1%). Work on these biological-based tactics continues. The role of large predators, crab and sturgeon, as a potential control was investigated. Adult Dungeness crabs enclosed in large pens in the bay were not able to reduce shrimp burrow density. The turnover dynamics of what are most likely sturgeon caused "burrowing shrimp feeding pits" was studied. Shrimp density was slightly reduced in feeding
pits, and pit turnover was high. Underwater video efforts failed to confirm that the pits were made by sturgeon. Additional quarterly sampling of a range of fish species, along with microscopic analysis of their stomach contents, is being undertaken to determine other potential predators of burrowing shrimp. Biweekly monitoring of the water column at a number of sites in Willapa Bay is yielding data on the distribution of larval burrowing shrimp and their stages in the Bay relative to water quality conditions (e.g., temperature, salinity, chlorophyll, etc.). These data and other relevant estuary processes are being added to improve GIS mapping of the Bay for use in burrowing shrimp management.
Impacts
Alternative methods for control of the burgeoning populations of burrowing shrimp in Willapa Bay must be found in order to sustain the oyster farming operations in Willapa Bay. Ten percent of the human population in the county bordering the Bay depends on a livelihood from the aquaculture of oysters and clams. It is possible that the application of the alternative to carbaryl spraying, the spikewheel application of imidacloprid, or the application of one or more of the natural controls, either separately or as part of an integrated pest management strategy (IPM), will solve the problem.
Publications
- No publications reported this period
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