The lab is currently focused on two main research lines, the first one is the dynamics of small-scale fisheries in a changing climate (and includes impact of ocean acidification on abalone fisheries in Baja California, shark conservation biology and the simulation of the effect of marine protected areas), the second is the control and elimination of infectious diseases with an important environmental component in their transmission cycle (most notably schistosomiasis in Western Africa, but we are working also on the dynamics of diseases of marine organisms).
Ultimately, our goal is to foster interdisciplinary knowledge and skills within our lab group with the aim of contributing to solve some of the major challenges society has to face, from the sustainable harvesting of renewable resources in a changing climate, to the control of infectious diseases of public health importance.
Fisheries and Conservation
Multiple Stressors and Abalone Populations
Eastern boundary current systems, including the California Current Large Marine Ecosystem (CCLME), routinely experience upwelling driven low pH, low dissolved oxygen (DO) waters, with the magnitude and duration of these events increasing over the past decade. With funding from the National Science Foundation Ocean Acidification Program, we are studying the consequences of ocean acidification and other climate-related changes (DO, temperature) on near shore marine communities in the CCLME. This work allows us to better anticipate possible ecological and fishery impacts due to increasing frequency and intensity of low pH and low DO events and help to inform adaptation strategies. We utilize an individual- to population-level approach to investigate how the effects of ocean acidification on abalone, in combination with low DO and changing temperatures, will manifest at the population level, and ultimately, the services these species provide to humans. We are pursuing this goal by 1) measuring and characterizing the temporal variability of pH, DO and temperature in nearshore abalone habitat in Monterey Bay, Central California, and Isla Natividad, Mexico and using hydrodynamic modeling to predict future changes in these regimes, 2) conducting laboratory experiments to investigate the effects of multiple stressors on the reproductive success, growth, calcification, and survival of juvenile abalone, and 3) developing demographic and bio-economic models to estimate the impacts of environmental and local anthropogenic stressors on the resilience of abalone populations and to assess what management and conservation strategies, including marine reserves, may contribute to buffering the negative effects of climate change.
Resilience in Small Scale Fisheries: Baja Case Study
Small-scale fisheries employ 50 of the world's 51 million fishers and produce over half of the world's annual marine fish catch, supplying most of the fish consumed in the developing world. Despite their overwhelming social and economic importance of small-scale fisheries, these systems are poorly understood. Community-based management, co-management, and market incentives can all foster long-term stewardship and ecosystem protection, but their applicability and success to date has varied. Beginning in the 1930's, the nearshore fisheries of Baja California were organized into local cooperatives, which were granted exclusive fishing rights on local stocks, including abalone, lobsters, oysters, clams, and shrimp. Cooperatives throughout the coast operate under different permits that give them greater or lesser degrees of control over their local resources, and vary broadly in their ecological setting and in the success and sustainability of their main fisheries (primarily for lobster and abalone). Our objective is to develop an integrated framework for addressing environmental and socioeconomic processes underlying the varying success of the small-scale fisheries of Baja California. Through our involvement in these multi-disciplinary research program studying the complex biophysical and socioeconomic feedbacks within two space-based approaches to marine management and conservation, marine protected areas and exclusive fishing rights, we are hoping to be able to make significant contributions to better integrating ecological understanding into conservation of marine seascapes and associated assemblages.
Large marine protected area (MPA) effectiveness
Large MPAs (regions where fishing is restricted) have recently been established throughout the world at an unprecedented pace, yet the value of these reserves for mobile species conservation remains unclear. The rapid establishment of large MPAs, some spanning over one million km2, has nearly doubled the total area of protected ocean on Earth in just five years. However, reef shark populations continue to decline even within some of the largest MPAs, fueling debates over the ability of protected areas to aid mobile species that occasionally transit beyond MPA boundaries. We seek to better understand how mobile species may respond to MPAs of this magnitude by electronically tracking the movements of reef sharks and fishing vessels throughout the Palmyra Atoll National Wildlife Refuge, a 54,000 km2 MPA located in the central Pacific Ocean.
Human impacts on coconut crab populations
Weighing in at up to 4kg and spanning up to a meter across, the coconut crab (Birgus latro) is among the largest native land animals on many Indo-Pacific islands. This jungle-dwelling crab has been hunted for centuries, but increasing human populations and ongoing habitat destruction have recently caused substantial population declines throughout much of the species’ distribution. An improved understanding of the coconut crab's ecology and the impacts of crab hunters are critical for tailoring effective conservation measures to meet these challenges. The primary objective of this project is to improve understanding of the critical habitat, home range, and harvest rates of the coconut crab (Birgus latro). We use a combination of electronic tracking, hunter interviews, and vegetation surveys to better understand how this species interacts with the surrounding ecological community.
Sea Star Wasting Disease
In the summer of 2013, sea stars off the Washington coast began "falling off the rocks - dead by the thousands." When similar reports came in from Alaska to Baja California, it became clear this was not an isolated event. Sea star wasting disease (SSWD) is characterized by the appearance of lesions surrounded by decaying tissue, typically followed by rapid disintegration and death, often within a few days. It appears to be caused by a virus, possibly in association with high water temperatures, but the pattern of disease occurrence does not match a typical "traveling wave" scenario with disease incidence spreading from an initial case. As an alternate hypothesis, we have developed a novel model which links both infectious processes and environmental drivers via the initial dispersal of an asymptomatic infection followed by a symptomatic disease outbreak triggered by accumulated temperature stress.
Eel Management Software
The Eel management software (EMS) has been developed in order to provide a user-friendly tool to assess the effectiveness of management plans for the endangered European eel (Anguilla anguilla). This software allows evaluating both production (i.e. escapement to the sea) of silver eels and fishermen catches in a specific site, in different conditions as actual, pristine (i.e. unaffected by antropogenic impacts) and potential ones as required by the European Regulation EC 1100/2007. The flexibility of the tool allows the user to consider several environmental and management scenarios by defining the characteristics of the site, the exploitation level of the stock and the management plan constraints, and eventually comparing the results obtained under different scenarios.
Although the EMS is based on the most trustworthy and up-to-date knowledge about eel population dynamics, it is just an approximation of reality; therefore, the outputs of the model should not be considered reliable in absolute terms. In contrast, the great usefulness of this software is that it allows the user to compare the effects of different management actions, to evaluate the advantages or disadvantages (in terms of silver eels escapement and fishermen catches) of adopting different management policies and to assess the effectiveness of different management plans.
Disease Ecology and Health
The Upstream Alliance
The Upstream Alliance is a partnership among scientists and citizens on four continents, working together to reduce schistosomiasis, a Neglected Tropical Disease and a disease of poverty. At The Upstream Alliance, we are creating solutions to naturally reduce schistosomiasis, while helping to fight hunger and alleviate poverty. Together, our partners are restoring prawns to their native waterways and developing a new sustainable prawn-farming enterprise for the health and well being of the local communities. Water projects like dams and irrigation schemes support agricultural expansion to feed the growing human population, now topping 7 billion worldwide. But these water projects come with costs in the form of degradation of ecosystems and in some cases, of human health. In West Africa, the Diama Dam, built on the Senegal River in the 1980’s, was followed by a massive outbreak of schistosomiasis, a waterborne parasitic disease that causes debilitating symptoms in humans. The dam blocked the migration of freshwater prawns, predators of the snails that carry the parasite. Without prawns, the snail populations exploded, and so did the disease. The changing distribution of fresh water and the loss of prawns upstream due to dam building has caused a rising burden of schistosomiasis in the developing world. Prawns are voracious predators of the snails that carry the schistosome parasite. So, more prawns equal fewer snails and less risk of parasites in the water. And that translates to healthier children and communities. Our disease control approach is to restore natural snail predators (prawns) within the aquatic ecosystems where schistosomiasis has emerged, especially in managed ecosystems like irrigation schemes throughout the developing world where some of the highest parasite transmission sites exist today.
The Program for Disease Ecology, Health and the Environment
The Program for Disease Ecology, Health and the Environment works with experts in public health, ecology, engineering, computer science, medicine and the social sciences to find sustainable environmental interventions for a range of diseases.
It expands on an initial keystone project called the Upstream Alliance, a multi-institution initiative seeking environmental interventions to curb the spread of schistosomiasis, a waterborne parasitic disease affecting about 250 million people. This project is featured in a new video by California Academy of Sciences, where the team’s reintroduction of native prawns at river access points at field sites in Senegal led to fewer disease-carrying snails and reduced transmission of schistosome parasites to people.
The Program for Disease Ecology, Health and the Environment is a joint initiative with the Stanford Woods Institute for the Environment and the Center for Innovation in Global Health at Stanford University’s School of Medicine. Its mission: To discover ecological solutions to humanity’s health challenges and to develop the next generation of planetary health innovators.