Research

Effects of ocean acidification on declining Puget Sound calcifiers

Increasing temperatures and ocean acidification are expected to have important and broad ranging effects on the marine environment. Accurate predictions of these effects are not possible due to a dearth of biologically meaningful empirical data to inform models. Nowhere is the need for information greater than in the inland and coastal marine waters of Washington, one of the first regions likely to experience the effects of ocean acidification on important marine calcifiers due to local upwelling events and the low buffering capacity of seawater in this region.

Seawater temperature, pH and carbonate saturation states are influenced by release and increase of atmospheric carbon through the burning of fossil fuels. The molluscan larval stage is already highly vulnerable to biotic and abiotic stressors, and their response to stress is likely be exacerbated in an acidified and warmer marine environment. Lower pH and elevated temperature alone and in combination can reduce shell calcification in mollusc larvae and can also affect pathogen-host dynamics by enabling pathogen proliferation and decreasing host response.

Larval development strategies differ among species, and we seek to understand the relative advantages and disadvantages of larval life history strategies under current and predicted temperature and pH conditions among three marine mollusks that are currently in decline. The tools needed to address the problem of ocean acifidication inherently demand both traditional and modern techniques across disciplines. We will work with a team of collaborators (biology, pathology, genomics, oceanography and aquaculture) to investigate effects of marine water pCO2, pH and temperature on the larval stage of sentinel primary consumers.

Our overall research objective is to:

Characterize the relationship between altered environmental conditions and health of larval molluscs under controlled conditions.
Specific objectives are to:

  1. Characterize responses observed in early life stages of four marine molluscan species to multiple stressors, which include increased dissolved pCO2, varying temperature and the pathogen V. tubiashii in controlled laboratory studies.
  2. Characterize molecular responses to selected stressors for future use under field conditions as predictors of environmental stressors experienced.
  3. Compare responses between two species with similar larval strategies.

Personnel

Funding provided by Washington Sea Grant Program 2010-2013

Threat to bivalve aquaculture and fisheries: The influence of emerging diseases and environmental change

Shellfish are a critical component of our marine ecosystems, an environment that is increasingly threatened by environmental change. In the Pacific Northwest the environment has changed in a manner that has contributed to increase mortality of bivalve larvae in hatcheries and also appears to have decreased natural recruitment. Several local shellfish hatcheries, upon whom nearly the entire bivalve culture industry relies, have experienced up to 59-80% losses during the post two years. Several factors have been attributed to this problem including temperature, acidification, and re-emerging pathogens. Given the large-scale environmental change observed in our marine ecosystems and the relationship of host stress response and pathogen virulence with environmental conditions, it is necessary to examine the problems facing bivalve larvae from a regional perspective that systematically assesses how the environment influences the spread of disease and the ability of oysters to effectively respond to stress. The goal of this proposal is to characterize the factors that threaten the aquaculture industry and wild shellfish. The primary approaches that will be undertaken involve both a series of laboratory experiments and environmental sampling. We will examine the impact of environmental stressors (elevated temperature and reduced pH) on disease expression (e.g. vibriosis and or OsHV) and larval bivalve survival. More specifically we will test the impact of single and multiple biotic and abiotic stressors on larval bivalves with a focus on the most economically important regional species, the Pacific oyster Crassostrea gigas.  In order to assess the impact of biotic and abiotic environmental factors on bivalve health, we will also assess the abundance of oyster and other larvae in Willapa, Dabob, and Netarts Bays in relation to water quality parameters (pH, temperature, DO, salinity, alkalinity, chlorophyll A, and pathogen load). The specific research objectives of this collaborative research (with PI Steven Roberts and co-PI Ralph Elston) are to:

  1. Characterize the interrelationship of altered environmental conditions, pathogen, and oyster response under controlled conditions.
  2. Identify factors in Pacific northwest hatcheries and in the wild that are associated with poor oyster larvae survival.

Upon completion of this research we will have a better understanding of how environmental change will impact our marine ecosystem. This information will allow us to better predict mortality events, improve hatchery practices, manage wild populations, and develop improved broodstock. Furthermore, bivalves are an excellent sentinel species for environmental perturbation and bio-monitoring procedures developed in this project could easily be transferred to other systems.

Personnel

Funding provided by the Saltonstall-Kennedy Program of NOAA 2010-2012 and UW School of Aquatic and Fishery Sciences

Understanding the roles of competing bacterial endosymbionts in abalone health, management, and restoration

Successful ecosystem-based management requires an in depth understanding of functional roles that different organisms play within ecosystems. This is especially important for potential pathogens of keystone species such as abalones, herbivores that inhabit intertidal and subtidal waters off California. Of the eight resident haliotid species, three are Species of Concern (pinto, green and pink abalones) and two are Endangered (white and black abalones). Two rickettsial bacteria (RLOs) are known from California abalones, but only one (the WS-RLO) is known to cause withering syndrome (WS) in Haliotis spp. All 7 of 8 California abalones examined are susceptible to infection, yet different species develop varying levels of WS and mortality, ranging from little to catastrophic. The WS-RLO is distributed from Crescent City, California south into Baja California, Mexico, yet clinical signs of disease are most severe at temperatures >17oC. We recently observed a new RLO in California abalones that infects the same tissues as the WS-RLO and, in a recent experiment with black abalone, was statistically related to tissue pathology & mortality. Yet, mortalities of juvenile black abs infected with both the WS- and new RLOs appeared to be delayed & significantly reduced relative to previous studies with the WS-RLO suggesting that the new RLO competes with the WS-RLO and reduces associated losses. It is crucial to identify and characterize the impact and distribution of the new RLO on abalone for effective ecosystem management and promotion of a successful abalone aquaculture industry.

We have developed a collaborative project with co-PI Glenn VanBlaricom and collaborators Pete Raimondi (UCSC), members of the California Abalone Aquaculture Industry and California Sea Grant Marine Extension Representatives to investigate the role of the new RLO in abalone health. Our overall research objectives are to understand the role of host-parasite relationships under varying environmental conditions. Our specific objectives include: 1. Identification of the new RLO using microbial and molecular methods; 2. Development of molecular tools to identify and quantify all RLOs known in California; 3. Determination of the geographic distribution of the RLOs by surveying wild abalone populations, farms and seawater; 4. Testing the pathogenic potential of the new RLO alone or in combination with other RLOs under varying thermal regimes via controlled laboratory and on-farm experiments. We have a 5th educational goal: to relay our findings to managers, scientists, students, NGOs and other interested parties through a workshop in year 3.

Personnel

Funding provided by California Sea Grant Program 2010-2013, UW School of Aquatic and Fishery Sciences and collaborators from the California Aquaculture Industry

Developing tools to control and diagnose Withering Syndrome in abalone

We have developed several PCR assays to detection and or quantify the WS-RLO in abalone tissues, seawater and other sample types. We are in the process of formally validating these assays for both analytical and diagnostic sensitivity and specificity.

Personnel

Funding provided by California Sea Grant Program, UW School of Aquatic and Fishery Sciences and NOAA Protected Resources Division, Long Beach, CA

Restoration of the pinto abalone, Haliotis kamtschatkana, in Washington State

In a threatened species, initial efforts to rehabilitate a species should be focused on obtaining the necessary information for a species recovery plan. This plan should examine the potential for rehabilitation first. If intervention is deemed necessary, supplementation should only proceed following research into the prospective impact of such a program on the wild target populations (Waples 1991). Our intention is to obtain the baseline information necessary to make informed decisions on whether and how a supplementation program for pinto abalone should proceed. This information includes derivation of the population demographics around the San Juan Islands (diver surveys and genetic analyses), examining and testing culture methods that maximize both the genetic variation and the survivability of outplanted individuals, and soliciting the opinions of stakeholders through workshops.

Since 2003, with our collaborators (WDFW Abalone Dive Team; NOAAs NWFSC-Mukilteo Field Station and Protected Resources Division; Taylor Resources, Inc.; Puget Sound Restoration Fund; Jamestown S’Klallam Tribe, Shannon Point Marine Laboratory of WWU) we have:

  1. Developed molecular tools for high throughput detection of target species presence in seawater samples.
  2. Characterized larval behaviors under experimental mesocosm conditions.
  3. Calculated juvenile and adult abalone abundances at index sites.
  4. Characterized the influence of rearing method on abalone behavior.
  5. Developed a pinto abalone hatchery and are assessing culture methods for optimal survival in the wild.

We are currently:

  1. Examining the biological relevance of genetically divergent ‘pinto’ abalone found in Northern Puget Sound.
  2. Developing optimal outplant methods to introduce and or aggregate abalone in Washington state to supplement declining populations.

Personnel

Funding provided by Washington Sea Grant Program, Washington Department of Fish and Wildlife, SeaDoc Society, NOAA Protected Resources Division, Russell Family Foundation, Taylor Resources Inc. and UW School of Aquatic and Fishery Sciences

Assessment of potential interactions between cultured and wild geoduck clams in Washington State

Geoduck clams (Panopea generosa) are an exceptional species for continued aquaculture development. Their large size (1 kg at harvest), rapid growth (4-6 year growout), high per-hectare biomass (80,000 kg/ha), and strong demand from Asia are contributing to the rapid growth of geoduck aquaculture. The extreme longevity of geoducks (up to 168 years) is another important factor: low mortality and natural recruitment necessitate a fishery exploitation rate well below demand, thus creating more market opportunity for cultured geoduck.

As geoduck aquaculture increases, we are examining the potential interactions between cultured and wild geoduck clams in Puget Sound with an emphasis on disease and genetic interactions. Via collaborations with the Pacific Shellfish Institute (PSI) and geoduck culture industry, we are also examining different predator exclusion methods to reduce environmental impacts of culturing these clams. In collaboration with Taylor Resources, Inc. and PSI, we are also developing hatchery methods to induce sterility to obviate genetic interactions between cultured and wild geoducks.

Personnel

Funding provided by National (2007 to 2010) and Washington Sea Grant Programs (2007-2009 and 2009 to 2011), Washington State 2009 to 2011), and the Saltonstall-Kennedy Program of NOAA(2010-2012) and UW School of Aquatic and Fishery Sciences

Herpes-like viral infections of Pacific oysters

The Ostreid herpes virus (OsHV) infects several bivalve species globally, especially the Pacific oyster Crassostrea gigas. Since the discovery of this pathogen in California in 2002, we have developed molecular tools and seed and larval challenge methods to further our understanding of the host-parasite relationship. Via the development and application of qPCR and rt-qPCR assays we have gained a better understanding of viral infection dynamics. This work was conducted in conjunction with OsHV research being done by collaborators: the Reece lab at VIMS, Elston lab at Aquatchnics, and Renault lab at IFREMER-La Tremblade, France. Currently, in conjunction with Steven Roberts’ laboratory, we are examining the host response to infection via sequence analysis of the transcriptome and differential display analyses. We are in the process of developing a suite of rt-qPCR assays to better understand how the host responds to infection. In addition, we are working with members of the California aquaculture industry, California Sea Grant Extension Service and the Bodega Marine Laboratory to assess the potential development of resistance to OsHV. See graduate student Colleen Burge web page.

Personnel

Funding provided by National (2001 to 2009) and California Sea Grant Programs (2008-2009), and UW School of Aquatic and Fishery Sciences

Transmission strategies of Ichthyophonus sp., a parasite of walleye pollock in the Bering Sea and Northeast Pacific

Infection with I. hoferi has been associated with mortality and reduced product quality in Chinook salmon (Oncorhynchus tshawytscha) and a decrease in mean age of Pacific herring (Clupea pallasii) in the North East Pacific. Ichthyophonus infections have also been reported in walleye pollock (Theragra chalcogramma), an important fished species that represents~70% (1.566 million metric tons) of the groundfish catch in Alaskan waters. This valuable fishery (~2 billion dollars per annum) is an important revenue source in the North Pacific. Although, mortalities of walleye pollock due infection by Ichthyophonus have not been reported, infections influence product quality. The taxonomy, prevalence, geographic range and reservoir of Ichthyophonus have not been characterized. In a collaborative project led by the Morado laboratory at the NOAA Alaska Fishery Science Center, we are developing molecular tools (real-time quantitative PCR assay) to identify and quantify Ichthyophonus in fish, seawater and plankton samples in an effort to better understand the ecology of this important parasite..

Personnel

Funding provided by the NOAA Alaska Fisheries Science Cetner and UW School of Aquatic and Fishery Sciences