A major goal of my research is to determine how fish and invertebrate species respond to both anthropogenic and natural perturbations. My dissertation work stressed experimental and modeling approaches, giving me a solid background in empiricism, quantitative techniques, and statistical analyses. I approach problems using multiple methods of inquiry (e.g., models, manipulative experiments, field observations, etc.) in order to achieve a thorough understanding of the system under study, and whenever prudent I collaborate across disciplines. Much of my research occurs in nearshore marine habitats, which are influenced by a suite of interacting natural- and human-derived pressures (physical disturbance, hypoxia, invasive species, and climate disruption and acidification) that in turn may impact aquaculture and shellfisheries.

 

An ecosystem modeling approach to investigate direct and indirect effects of geoduck aquaculture expansion in Washington State

Geoduck clam aquaculture operations involve procedures that may disturb ecological communities, habitats, and ecosystem processes. Rapid expansion of intertidal geoduck aquaculture operations in Puget Sound has raised concern among managers, conservation organizations, and the public regarding industry practices that may alter nearshore ecosystems. Despite increased understanding of the ecological effects within or near farm sites, key uncertainties remain regarding the broader ecosystem effects of continued geoduck aquaculture expansion. We will synthesize five years of data collected at geoduck aquaculture sites and reference beaches. Our objectives are as follows: (1) to evaluate direct and indirect ecosystem effects in scenarios involving future increases in the extent of geoduck aquaculture; (2) to identify appropriate indicator species that reflect the broader status of ecosystem health in response to geoduck aquaculture expansion; (3) to determine gaps in data to guide future research; and 4) to provide a tool for managers to aid in screening policy options. We will integrate empirical field data into a published food web model of central Puget Sound, developed in the Ecopath with Ecosim (EwE) software. Once the ecological effects are represented in the model, we will devise scenarios (guided by stakeholder input) in which we perturb the system by incrementally increasing the total biomass of geoducks, at levels up to, including, and surpassing projected intensity of geoduck aquaculture. In order to engage stakeholders and increase management value, we will convene an advisory group of local, state, and tribal representatives to develop model scenarios to be explored. In follow up meetings, model outputs will be discussed to develop recommended strategies for future geoduck aquaculture development.

 

Crab Team: citizen science monitoring for invasive European green crab in Puget Sound

The European green crab (Carcinus maenas) was first detected in Washington waters in 1998 after warm El Niño currents spread larvae of California populations as far north as Vancouver Island. Because of perceived risks to coastal resources, the green crab was designated a deleterious species in Washington State, which among other actions, mandated monitoring and control of the species in state waters. Green crab recruiting to coast estuaries failed to establish large populations, and none were found in inland waters of Puget Sound; consequently, monitoring and control efforts were curtailed. However, in 2012, Canadian wildlife officials discovered a population of green crab in Sooke Inlet near Victoria, British Columbia, well within the Strait of Juan de Fuca. The purpose of the present study is to design and implement a habitat-specific, volunteer-based monitoring program for inland waters of Washington State. To this end, we have produced a habitat suitability map for all shorelines using coarse physical, biological, and access characteristics observable in aerial and satellite imagery. Current effort focuses on recruiting and training volunteers to monitor for the species, testing and refining a robust yet practical protocol for high-risk habitats, and developing strategies to sustain the program. Current projects include testing the efficacy of different baits, assessing the educational effectiveness of training, and evaluating marketing and outreach strategies.

More information here.

 

Using bioenergetics models to evaluate ecological and fishery impacts of climate change on Dungeness crab

Dungeness crab are culturally and economically important in Washington State. Yet there exists little information that could be used to assess potential climate effects on populations. The goal of the study is to understand the role of current and future climate change-driven changes in physical and trophodymaic conditions on the distribution, ecology, and fishery for Dungeness crab in coastal and inland Washington waters. Climate change will likely impact crab throughout their life-cycle. We aim to evaluate one of the most immediate direct potential impacts of climate change on Dungeness crab and the reliant fishery; climate-driven changes to post-settlement growth, distribution, reproduction, and fishery size at age. In order to evaluate climate impacts we will estimate growth from temperature specific bioenergetics models for Dungeness crab and competitive conger, graceful crab. In particular we aim to (1) conduct experimental feeding trails to determine the effect of temperature and weight on crab foraging rates, (2) use experimental results to parameterize bioenergetics models for Dungeness crab and graceful crab, (3) use hindcasts of the models in conjunction with existing climate and benthic data to understand the role of temperature in determining past and current crab growth rates and population productivity, and (4) conduct management strategy evaluations using model estimated growth rates and down-scaled IPCC climate forecasts to gauge future impacts of climate change on Dungeness crab fisheries and the benthic ecosystem and explore potential fishery management measures for mitigate for climate impacts and adapt to changing conditions.

 

Evaluating the effects of climate, predators and prey, and management actions on data-poor species: application of qualitative network models to blue king crab

The Pribilof Island blue king crab (Paralithodes platypus) stock, closed in 1998 and declared overfished in 2002, is the only overfished Alaskan stock.  Despite no directed fishing, the stock has not improved since 2002. The reasons for the decline and lack of recovery are unknown.  As part of a recently completed data rescue project (NPRB Project 1321), we recovered cruise data from 1983-84 that quantified the density and habitat associations for every life-history stage of the blue king crab from larvae to adults. Because comparable contemporary data are unavailable, there is little information with which to quantitatively consider management options or evaluate response of the blue king crab stock to environmental change. We propose to combine information from published studies, recovered data, and stakeholder input to develop robust qualitative models that can be used to help: 1) evaluate the strength of interacting climate, biological, and human-mediated drivers of historical decline; 2) identify management tools likely to promote stock recovery; and 3) understand how the stock and associated ecosystem might respond to perturbations, such as climate change. Qualitative network models (QNM) represent a mathematically formalized conceptual modeling approach for linking changes in blue king crab to key ecological and environmental variables. The QNM framework will allow us to make qualitative predictions about response of the stock to management actions and environmental changes. The results will yield information for prioritizing data needs in future quantitative investigations. Moreover, QNM can incorporate stakeholder input and Local Ecological Knowledge (LEK), and we will engage a variety of groups in workshops to develop models, test scenarios, and evaluate outcomes. In addition to QNM results, the work we propose here will enhance ocean literacy through targeted education and outreach activities, including development of K-12 classroom education materials and senior undergraduate thesis research and training.