Ongoing projects

Impacts of Marine heatwave persistency on Prince William Sound herring population


Understanding Prince William Sound Pacific Herring population dynamics

Branch Lab 

Dias et al. 2022. Influence of environmental and population factors on Prince William Sound herring spawning phenology. DOI:

In Prince William Sound, Pacific herring is a key forage species that once supported commercial and subsistence fisheries for many decades, but collapsed in 1993 and has yet to recover. Our results are a critical first step towards assessing how changes in spawning phenology impact first-year survival of herring offspring and potentially contribute to persistent poor recruitment that has inhibited the recovery of the Prince William Sound population. 

Past projects

Juvenile great white shark range expansion due to climate change: Incorporating citizen science and environmental data. 

Monterey Bay Aquarium Great White Shark Research

Tanaka et al. 2021. North Pacific warming shifts the juvenile range of a marine apex predator. Scientific Reports. 

During the 2014–2016 North Pacific marine heatwave, unprecedented sightings of juvenile white sharks (Carcharodon carcharias) emerged in central California. We have found that thermal suitable habitat for juvenile sharks declined and was at its lowest in 2015 at the peak of the heatwave. Here we discuss this opportunity to engage the public on climate change through marine megafauna.   

Evaluating fishing effort reduction and habitat restoration as management strategies for anadromous forage fish.

Dias et al. 2021. Contrasting fishing effort reduction and habitat connectivity as management strategies to promote alewife (Alosa pseudoharengus) recovery using an ecosystem model.

Recently more attention has been paid to the management of forage fish, including anadromous river herring (Alewife Alosa pseudoharengus, blueback herring A. aestivalis) and American shad (A. sapidissima) due to their status and historical ecological and economic role. Little is known about the impact of their biomass loss on marine food webs, and what management practices are likely to be successful in promoting their recovery. We derived the potential productivity from historical habitat estimation, considering full river to ocean connectivity. We then used Ecopath with Ecosim simulation tool to analyze the management strategies that focused on anadromous forage fish, by creating scenarios of fisheries reduction and habitat restoration. 

Opening the tap: Increasing river to ocean connectivity in the Northeast US Marine Ecosystem.

Habitat loss is signaled to be one of the biggest threats to wildlife. Aquatic species also have been impacted by the loss of habitat, and connectivity between water bodies. For some species, like anadromous fish that depend on fresh and sea water to complete their life-cycle, the construction of dams and other barriers had a big impact on their populations. 

The goal of my project is to use historical data to look at the impact of river to ocean connectivity in marine food webs, with focus on small anadromous (alewife, Alosa pseudoharengus). These fish are the main food for marine birds, orcas, seals, and big fish. Think of them as the hot dogs of the sea. The results to this project show benefits to increasing the connectivity, making the marine food web more resilient to changes. 

Developing tools for the best use of the bucks on species of concern conservation and monitoring. 

Marine Protected Areas (MPAs) are used as a measure to protect and conserve marine resources and ecosystem. In a recent study, Gill et al. (2017), showed that MPAs conservation impacts were negatively impacted by reduced staff and financial resources. Limited funds is a high concern for Marine Protected Areas, and new methodologies to reduce costs associated with monitoring activities are welcome. 

To address the question of how to create an effectively monitoring program while having limited budget, I developed a suitability model focused on manatees, estuarine dolphins and sea turtles. This information will help the RESEX Soure, a multi-use protected area in Northern Brazil, to develop their monitoring plan for species of concern. 

Sea turtle records at the Environmental Protection Area of Algodoal-Maiandeua, Para State, Brazil. 

The Para State Coast, in Northern Brazil, is well known for its dynamic environment and high primary productivity as the Amazon and Tocantins rivers meeting the Atlantic Ocean (de Matos & Lucena 2006). Despite fishermen reports of sea turtle occurrence along the coast (Brito et al. 2015), there is a lack of documentation and publications regarding sea turtles in the area. This study is the first peer review published documentation.

Mark and recapture of green sea turtles in Baja California Sur, Mexico.

The Pacific coast of Baja California Sur is a key forage ground for juvenile Eastern pacific green sea turtles (Chelonia mydas) from rookeries in the Eastern Pacific. Green sea turtles have suffered severe overexploitation, resulting in a population decline of over 90% between the 1950-70´s. Today, despite a total ban on fishing and trade of sea turtle goods, bycatch and poaching remain major threats in Mexican waters. 

Assessing the status of juvenile green sea turtles in foraging zones is required to develop effective conservation strategies, thus multi-year population ecology data is needed. Our study aimed to determine the status of juvenile green sea turtles at four coastal lagoons in Baja California Sur, Mexico, under different management rules. 

Master's thesis in Spanish

Picture by Maisa Fernandez
Picture by Maisa Fernandez