A healthy microbiome is key to fitness in sharks and rays, but increasing amounts of heavy metals in the ocean could disrupt these microbes and impact shark and ray immune systems. Miguel wants to understand shark microbiomes because impaired immunity will make already threatened sharks and rays more susceptible to environmental stress. His project will sample gut microbes from smooth hammerheads and giant electric rays in the Gulf of California, Mexico. By describing the microbiome in these sharks and rays from both polluted and unpolluted sites, Miguel hopes to understand if heavy metals lower microbial diversity.
I was born in La Paz in southern Baja California, Mexico, where we are privileged to be surrounded by pristine beaches and incredibly rich marine fauna. As my father was a marine biologist, when my brother and I were young we spent a lot of time at sea, where he taught us to appreciate and protect all marine animals. Naturally, this led me to study marine biology too. But while I really loved field trips and ecological studies, at some point I realised that I was more interested in understanding marine life at a deeper level. So I shifted from...
To describe the gastro-intestinal microbiome of sharks and rays from a site with high levels of heavy metals and from two other unpolluted sites. With this information we will attempt to determine whether heavy metals induce lower diversity in the microbial composition and to identify potential biomarker communities.
The gastro-intestinal microbiome in animals is a crucial factor in their health and their response to the environment. Heavy metals can disrupt microbial communities with deleterious effects on the host’s metabolic capacity or immune system, resulting in the host being more susceptible to disease or environmental fluctuations. This project will provide baseline information about the microbiome diversity in a pelagic shark and a demersal ray and will identify changes in the composition of their microbiomes due to heavy metal pollution.
The microbial community present in the gastro-intestinal tract of animals plays a pivotal role in food digestion and nutrient uptake. The composition of the gastro-intestinal microbiome of terrestrial and marine animals can be affected by the presence of heavy metals; either the diversity of bacteria may be reduced or the abundance of metal-resistance bacteria may be increased. Such structural shifts in the microbial composition can be used as bio-indicators when monitoring the health status of elasmobranchs. However, there are still no comprehensive studies that describe the core microbial composition of sharks and rays. It is therefore important to first characterise the microbiome composition of the gut in species with different lifestyles and diets and then determine whether heavy metal pollution induces a shift from the ‘normal’ composition to a low-diversity microbiome community.
The Gulf of California in Mexico has a rich diversity of elasmobranch species, resulting in an important small-scale fishery that targets sharks and rays. Moreover, the coastal region around Santa Rosalia, inside the Gulf of California, is known to have high levels of heavy metals due to historical copper-mining activities. In particular, high levels of copper, zinc, cobalt, manganese, lead and uranium have been identified in sediments and have led to an important accumulation of these metals in several invertebrates. As top predators, sharks and rays are particularly vulnerable to the bio-accumulation of heavy metals, since the most important route of heavy metal uptake is through food. Previous studies have already detected the presence of heavy metals in the tissue of sharks and rays from the Santa Rosalia basin. In this project we aim to find out whether microbial diversity is lower in sharks and rays from a site with high levels of heavy metals in relation to sharks and rays from unpolluted sites.
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.