Brittany is using a combination of methods to understand the vulnerability of gulper sharks to longline fisheries in New Zealand’s South Pacific Ocean. She will be satellite-tagging gulper sharks and looking at post-release mortality (how likely are gulper sharks to survive being caught and released in fisheries?). She’ll also explore how gulper sharks respond to the stress of being caught, try to confirm a nursery ground, and describe gulper shark movement patterns as they overlap with fisheries activities. All this information will feed into improved management for these vulnerable deep-sea sharks.
I grew up in Canada in a relatively small city nowhere near the ocean. The land barrier, however, never hindered my interest in the marine environment. I still remember how excited I was when I saw my first ocean animal (a humpback whale) at the age of 12. After finishing my undergraduate degree, I moved to New Zealand and now I am never more than a walk away from the sea. Every single day, I look out the window and see the ocean – and never get tired of the view.
When I agreed to take on...
The primary objective of my project is to understand gulper shark movement patterns in the South Pacific and the sharks’ vulnerability to longline fisheries.
Gulper sharks (genus Centrophorus] are now among the most threatened of the deep-water sharks. Their sensitive biology and a lack of research and conservation effort for these sharks has led to the quiet and unnoticed disappearance of many populations around the world. In order to implement management and conservation action, improved information is required to understand gulper sharks’ ecology and the complexities of their interactions with fisheries.
Sharks are an important economic resource for fisheries. Gulper sharks are no exception and are caught as targeted catch and bycatch in small-scale and industrial fisheries. They are exploited primarily for their liver oil, which is considered the most valuable of shark liver oils. Gulper shark fisheries are known for their boom-and-bust nature over very short periods of time. What do these declines in catches mean? It could be that there was no longer a market for them and the fisheries shifted to some other marine resource, but it is more likely that the declining catches reflect a collapse in shark abundance. Despite the known vulnerability of gulper sharks, there is little to no management action in place to encourage sustainable harvesting or conserve their depleted populations. The complexity of managing these species becomes more pronounced when they are shared across nations. Targeted fishing has been banned in some areas, but gulper sharks are still at extremely high risk of capture in trawl, longline and gill-net fisheries that target other species.
Deep-water sharks often receive less attention than their inshore and pelagic counterparts due to the perceived notion that they are out of sight and out of mind – existing at depths beyond the reach of current fishing activities, they face a lesser degree of threat. As coastal fisheries have been depleted, however, there is renewed interest in expanding – or ‘unlocking’ – fisheries into deep water, where distant and less-fished locations are thought to have unexploited fish populations. Such interest in the deep sea further threatens the survival of gulper sharks. While the deficiency of data on gulper sharks provides ample opportunity for exciting scientific discoveries, it also highlights the imperative to collect information about them so that sound management and conservation decisions can be made.
The aim of this project is to understand the ecology of gulper sharks and their vulnerability to longline fisheries in the South Pacific, specifically around New Zealand. Five activities will lead to this aim:
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.