Our changing global climate is bound to impact the ocean’s top predators, but how exactly do we know what the outcome will be for sharks? Eloise is keen to zoom in to understanding the genetic diversity of four understudied shark species to answer this question. She is studying the genes associated with the shark immune system, and assessing how they are linked to sharks’ survival in different environments. The information from this project should help manage important ocean ecosystems in the future, with an understanding of how sharks adapt to their changing environment.
I grew up in Honduras, Central America, about two hours from the Pacific Ocean and eight hours from the closest beach on the Caribbean coast, so my exposure to anything marine-related was very limited. It wasn’t until I relocated to Florida with my family and visited the Miami Sea Aquarium at the age of 12 that I decided I wanted to work with marine animals when I grew up. Even then, my plan to become a marine biologist didn’t become concrete until I entered college. As an undergraduate I majored in biology, focusing on all the courses relating to marine...
To determine how sharks adapt to their environment and to measure the effects of climate change on the distribution of locally adapted shark populations.
Elasmobranchs are keystone predators in most marine food webs, so declines in populations can have catastrophic effects on the health of marine ecosystems. Successful management at an ecosystem level requires an understanding of how elasmobranchs adapt to climate change, which we can measure by addressing the diversity of functionally important genes. This project is important to shark conservation because it studies immune system genes and their role in the survival and distribution of shark populations.
Elasmobranchs have various physiological and behavioral features that have enabled them to survive in diverse environments. This study will focus on developing and applying novel genetic tools to identify local adaptation to environmental conditions and climate variability. Local adaptation gives a population higher fitness at its native site compared to individuals introduced to that site. But elasmobranchs are a difficult animal model in which to measure local adaptation for two reasons: firstly, the difficulty of keeping them in captivity for laboratory experiments that examine adaptation; and secondly, because they are long lived, mature late, produce few young and reproduce at long intervals, it is impractical to study local adaptation in the next generations. Therefore, candidate genes that potentially respond to environmental stressors are the next best thing to determine whether non-model organisms like sharks adapt to their local environment. A particular region in the elasmobranch genome that is a target for local adaptation is the major histocompatibility complex (MHC), which is part of the adaptive immune system that evolved to deal with pathogens encountered via new prey types and to protect large, live-born offspring. In general, the more diversity in the MHC leads to a more effective immune system, but if the population is locally adapted to its environment, then there is likely to be lower MHC diversity but potentially unique MHC variants that are specific to that environment. Thus, understanding differences in MHC diversity within populations will enable us to identify the species/populations/habitats that are most vulnerable and to model future shifts in habitat distribution and dispersal patterns. By approaching conservation in this way, we can not only focus on the organism itself, but also determine how ecosystem health will promote population genetic diversity and survival.
Incredible progress made in the field of shark genomics, a field severely understudied and not widely applied to conservation.
Outside the USA, The Bahamas is the only place where Critically Endangered smalltooth sawfish can reliably be found. Tristan wants to ensure that protection measures in The Bahamas are understood and enforced as far as sawfish are concerned to close the current gap between policy and the people. He’ll be using aerial surveys, sonar and BRUVs, combined with interviews that draw on local knowledge, to identify essential sawfish habitats that need protection. Engaging with the community through workshops and by training students and meeting with government, Tristan intends to advocate for smalltooth sawfish protection throughout The Bahamas’ territorial waters.
Steven and Kevin are using genetic techniques to understand how Caribbean reef shark populations are connected across the extent of their range. Populations of this Endangered shark are in decline generally, but where they are managed and there is effective protection, their numbers are stable. With the integration of the correct information, Steven and Kevin are convinced that we can give Caribbean reef sharks a better shot at recovery and population stabilisation. They will also explore any barriers to connectivity, looking to the future recruitment and recovery of these sharks.
With very little information available about Endangered sicklefin devil rays, their seasonal aggregations at sea mounts in the Azores give Sophie an opportunity to learn more about their lives. She will be collecting satellite-tracking data that show how they move in the Azores’ exclusive economic zone. The information she collects will be used to develop maps of how the rays are using the zone and to identify essential areas that multiple species use. With this information at hand, Sophie hopes her work can contribute to a network of marine protected areas.