Assessing the status of marine species and ecosystems to catalyze improved management
Marine Conservation
Sharks
Sharks are iconic marine predators, but most species are highly vulnerable to overfishing. Exploitation of these predators, both as bycatch and as direct targets for their meat and fins, has increased substantially globally over the past half century.
For two decades, Julia has conducted research examining the status of sharks, working to inform improved conservation of these species. Her research, published in Science, provided the first demonstration of regional scale declines in apex predatory sharks (Baum et al. 2003). Subsequent analyses of scientific expeditions from the 1950s revealed the near extirpation of the oceanic whitetip shark from the Gulf of Mexico (Baum & Myers 2004), while analyses of fisheries observer data and research surveys showed declines of many species in the Northwest Atlantic (Myers, Baum et al. 2007; Baum & Blanchard 2010). Julia’s work has also advanced understanding of top-down control in the ocean (Myers, Baum et al. 2007, Baum & Worm 2009). In collaboration with scientists at NOAA, she then turned to Pacific reef sharks showing that the 'human signal' is now the primary determinant of grey, whitetip and other reef shark abundances in the Pacific Ocean, overwhelming the influence of oceanographic productivity and temperature (Nadon et al. 2012). More recently, Julia has worked with students on eastern Pacific sharks and rays at Cocos Island, Costa Rica. This work showed declines of many species, suggesting suggest that this UNESCO heritage site and marine protected area (MPA) is not effectively protected (White et al. 2015), and that many species are sensitive to temperature changes associated with El Niño events (Osgood et al. 2021).
Conservation of the Fraser River Estuary
Estuaries are amongst the most important and productive marine ecosystems. British Columbia’s Fraser River Estuary (FRE) is the mouth of one of the largest salmon bearing rivers in the world, supports the highest concentration of migratory birds in Canada, and is home to half of BC’s rapidly expanding urban population. Without timely and effective conservation management, these goods and services are at risk. Water pollution and habitat loss resulting from industrial and urban development, exploitation of fish stocks, and climate change are a few of the key threats. Led by post-doc Laura Kehoe, and conducted in close collaboration with Dr. Tara Martin, our Meopar-funded project focused on identifying key management actions needed to ensure the FRE’s long-term resilience. We brought together experts in the ecology, sociology, economics and management of estuarine systems and the FRE, along with fishers and other nonspecialists with local knowledge to estimate the costs, benefits, and feasibility of different management actions for conservation of the FRE using a Priority Threat Management (PTM) assessment (Kehoe et al. 2020). See our Media page for more on this work. Together, we have also now completed a salmon focused PTM (Chalifour et al 2022), led by PhD student Lia Chalifour and in collaboration with Pacific Salmon Foundation, to identify priority management strategies for salmon conservation. Lia also worked in the Fraser River Estuary to quantify habitat use by juvenile salmon and other fishes (Chalifour et al. 2019, Chalifour et al. 2020).
Photo credits: Hammerhead shark (Unsplashed), Fisherman (Unsplashed), Grey Shark (Kristina Tietjen), Fraser River Estuary work (Misty MacDuffee), Bottom photo (Misty MacDuffee)
