MERHAB 2007: Project Summaries

Institution: NOAA Center for Coastal Fisheries and Habitat Research and Northwest Fisheries Science Center

Investigators: W. Litkaer, P Tester, V. Trainer, T. Stewart

Abstract

Identification of the toxins produced by harmful algal bloom (HAB) species directly from environmental samples is currently a critical field of active research. Public health officials, marine resource and water quality managers, researchers, and shellfishermen all desire rapid, inexpensive and sensitive assays capable of detecting these toxins. This proposal outlines the development of a novel field test for domoic acid that can be performed by resource managers without the need for special training or laboratory equipment. Domoic acid (DA) is produced in the coastal waters of the United States by several diatom species in the genus Pseudo-nitzschia. DA is a neurotoxin which accumulates in the food chain resulting in mortalities of invertebrates, fish, birds and marine mammals, including sea otters and sea lions. Further, the accumulation of DA by shellfish represents a public health concern. Consumption of high levels of DA can result in amnesic shellfish poisoning, with mild to severe neurological symptoms and in rare cases, death. Significant economic losses to coastal communities due to lost shellfish harvests and reduced coastal tourism also result from toxic events.

The work outlined in this proposal builds on the accomplishments of a prior MERHAB proposal which successfully demonstrated a laboratory-based quantitative enzyme-linked immunosorbent assay (ELISA) for DA. This NOAA assay has been adapted to a commercial format and kits are currently being tested by academic, tribal, NGO and state agencies on the U.S. West Coast. The assay gives results that are comparable in sensitivity and accuracy to HPLC in approximately 1.5 hours and will likely prove useful in making regulatory decisions in the future. Though highly accurate, the NOAA ELISA assay requires a trained technical staff and approximately $20,000 in laboratory equipment. Resource managers and state health officials have been favorably impressed with the speed and sensitivity of the assay, however, they are requesting further development of the assay to a format that can be used reliably in the field. This proposal is in response to the need for an affordable semi-quantitative methodology for measuring DA concentrations in field samples without specialized equipment or extensive training for test kit users. 

Development of a "dip stick' type ELISA assay is now possible because of recent advances in computer controlled deposition of fluids such as antibody solutions on membranes via an inkjet printer. This technology has been successfully used to develop an analogous commercial field assay for mercury which has been approved for use by the EPA. The readout from the proposed DA 'dip stick' assay will be colorimetric, will require no specialized instrumentation, and has an anticipated price of ~$8.00 per sample. The target users for the assay include resource managers, public health officials, commercial fishermen wishing to spot check seafood for elevated levels of DA and citizen monitoring groups. We are working closely with MERHAB funded groups in California and Washington to incorporate toxin detection methods into HAB monitoring programs. These groups are willing to adopt cost-effective monitoring techniques for DA into their routine monitoring efforts. The DA 'dip stick" test kit we propose addresses a primary objective of the 2007 MERHAB request for proposals for improved diagnostic techniques for detecting and monitoring of HAB toxins.

Institutions: Oregon State University, University of Oregon, Oregon Departments of Fish and Wildlife and Agriculture, and NOAA NOAA Fisheries Newport Oregon

Investigators: P. Strutton, M. Wood, M. Hunter, W. Peterson

Related Links:

http://oregonstate.edu/dept/ncs/newsarch/2007/Sep07/habgrant.html

http://www.dfw.state.or.us/MRP/shellfish/razorclams/plankton.asp

Abstract

Phycotoxins associated with algae producing saxitoxin and domoic acid have had a significant impact on Oregon coastal communities and their economy for decades. For example, in 2003, the Oregon Department of Fish and Wildlife (ODFW) estimated that the cost of domoic acid-related closure of the razor clam fishery at Clatsop Beach alone cost the local communities $4.8 million. Even so, very little is known about the oceanographic conditions that promote the growth of toxin-producing organisms, the mechanisms of delivery of phycotoxins to harvestable shellfish, or the environmental signals that help predict the end of HAB events. At present, closure of shellfish beds in Oregon is based on monthly or bi-weekly sampling of sentinel invertebrate species for the presence of toxins and there is no comprehensive event response plan in place to help minimize the impact of HAB events on coastal communities. The sampling strategy for shellfish monitoring is based on a pragmatic approach that targets months and locations that have been identified as “hot spots” in previous years. This project is designed to provide the scientific data needed to understand the ecological mechanisms underlying the occurrence of HABs in Oregon. By partnering researchers from state universities and NOAA with representatives of agencies responsible for the state’s monitoring programs we will also be able to use the scientific understanding and methods developed for this project in a more ecosystem-based approach to HAB monitoring and event response in Oregon.

The goals of this project are to 1) use remote sensing, ship-based field sampling, RADAR derived current data and autonomous underwater vehicles (gliders) to confirm the role of upwelling and cross-shelf transport in the population dynamics of HAB species off Oregon, 2) to sample sedimentary environments in coastal Oregon to determine the distribution of resting stages of saxitoxin-producing dinoflagellates, and to obtain data needed for a temperaturedependent model of germination dynamics for these resting stages, 3) to combine data from the oceanographic research component of the project with data from ongoing plankton and shellfish monitoring programs to develop a streamlined ecosystem-based HAB monitoring and event response program for Oregon, 4) to use educational outreach and regular meetings of all involved personnel to determine the essential components of rapid event response programs for Oregon. Our vision is that this event response plan will involve a cadre of trained professionals and stakeholder volunteers with real-time access to information from glider deployments, satellite imagery, surface currents from coastal RADAR and other interpreted environmental data. While extensive research has been conducted on the causes and patterns of HAB events in California and Washington, the Oregon coast has generally been ignored even though it represents a key transition zone in west coast oceanography. This project will play a key role in filling that gap while simultaneously improving Oregon’s capacity for HAB monitoring and event response.