Shark Awareness Day: Plastic pollution – problematic for sharks and rays.

For Shark Awareness Day 2019 we have been chatting to a few of our elasmobranch (that’s sharks, skates and rays) researchers here the the University of Exeter! In this blog we talk to Kristian Parton one of our Masters by Research students based at our Penryn Campus. He has recently published his first research paper giving a global overview of shark and ray entanglement. Below he tells us about his research and what he has found.

Words by Kristian Parton, Masters by Research Student at the University of Exeter, Penryn Campus

Numerous shark populations around the world are under-threat from a variety human impacts, the most notable of these being overexploitation and bycatch. Plastic pollution and marine debris is also an ever-growing threat to species inhabiting the marine environment, having direct impacts on fish, sea turtles and marine mammals. There is little existing scientific knowledge on the impacts of marine debris on shark and ray species. Over the last year, I led a team of researchers from the University of Exeter seeking to investigate the impacts of anthropogenic (human-made) marine debris on elasmobranch populations across the globe. Our literature review was published this week in Endangered Species Research, in which we used novel data collection from social media site “Twitter”, as well as pre-existing data in the scientific literature. We discovered that the threat of marine debris to sharks and rays is likely underreported and is without doubt of clear animal welfare concern, although it is unlikely to have wide-ranging detrimental population level effects.

We managed to identify that “ghost fishing gear” was the category of marine debris responsible for entangling the majority of elasmobranchs. Ghost fishing gear is fishing equipment that has been discarded or lost at sea, and is distributed by ocean currents and winds. Ghost gear indiscriminately catches and kills a host of marine life, including sharks and rays.  We also discovered the majority of entangled individuals were found in the Atlantic and Pacific oceans, although recommend that more research should also be conducted in the Indian ocean – a known hotspot for elasmobranch biodiversity. In the scientific literature the most common entangled species were lesser spotted dogfish and spiny dogfish, two species regularly found off the coast of Cornwall. We highlight that sharks and rays who have specific habitat niches (e.g. those that inhabit the seafloor or species that occupy open ocean habitats), as well as those who display migratory movements may be at higher risk of entanglement in marine debris.

This Short-fin Mako Shark has been entangled in fishing rope which has caused scoliosis (deformation) of its spine. Image by Daniel Cartamil

By using a novel method of data collection via social media site “Twitter”, we were able to identify several different species of shark and ray that were a victim of entanglement, but weren’t found as entangled in the scientific literature. This included whale sharks, basking sharks and oceanic white-tip sharks. Twitter also highlighted additional entanglements hotspots that again weren’t displayed in the scientific literature.

Although not one of the major threats to sharks and rays, entanglement in marine debris still presents a risk to elasmobranchs, particularly from an animal welfare perspective. With further research on the topic, it could be revealed that this is occurring at far higher levels than we have reported. Social media has now become integrated into today’s society, so using it in a positive way to help reveal additional entanglement reports is a real bonus. With millions of users, the global reach of social media is unprecedented and scientists could now start to tap into the virtual databases that exist on the web.

From this research, we have set up an online entanglement report form in collaboration with the Shark Trust. This will allow citizen scientists across the globe to submit their shark and ray entanglement sightings, and will significantly help scientist further quantify this risk to ever declining elasmobranch populations.

Follow Kris on Twitter.

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, biological,  medical, engineering, humanities and social science fields.

Find us on: Facebook : Twitter : Instagram : LinkedIn  

If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!

Shark Awareness Day: Eye of the Tiger – Conducting Landing Surveys in Sri Lanka

For Shark Awareness Day 2019 we have been to talking to some of our elasmobranch (that’s sharks, skates and rays) researchers! Here, University of Exeter PhD student Claire Collins tells us about her research in Sri Lanka working to understand the shark fishery there so we can better manage them.

Tiger shark awaiting sale by shark traders in the early morning

Words by Claire Collins, University of Exeter PhD student.

I am 2nd year PhD student studying the socio-economic context of pelagic fisheries in Sri Lanka and India, specifically distant water vessels that target sharks (along with other large pelagics). As part of my research I will study the socio-economic value chains associated with sharks, the spatial movements of vessels and the perceptions of fishers with regards to national and international conservation regulations. To do this I will use a variety of methods including landing surveys, focus groups, household surveys and observational data. It is hoped that at the end of the project we can understand more about what motivates fishers to target sharks in distant water areas and how policy and management can be improved to benefit fishers’ livelihoods and shark populations.

Sharks are threatened globally by both targeted fisheries and through accidental capture in other large pelagic fisheries. Understanding the impact of anthropogenic activities is important and relies on accurate landings and discards data. However, for many fisheries globally the status of sharks as bycatch, and the difficulties in identifying them to a species-level means that we don’t have a clear idea of levels of fishing. The Indian Ocean has been identified as an area where populations of sharks are particularly poorly understood. As part of my PhD project I will be focusing on collecting data on landings and discards of sharks, as well as fishers perceptions of their livelihoods as shark fishers and how management and regulations effects them. One way to collect this data is through landing surveys in markets. These surveys are dual purpose for us, as we are able to collect landings data (including information on price and who is buying them) and we also get to speak to people whose job it is to understand shark movements and populations; the fishers!

Fishers with sharks caught incidentally during fishing for large pelagics such as Tuna and Billfish

Market surveys are not for the faint-hearted as they are frantic, start incredibly early (3AM at one of our sites) and the resulting smell means researchers are often unsuitable for travelling on public transport/sitting in cafes afterwards! Upon arriving at the markets researchers familiarise themselves with fishers and traders and look out for the first landings of the day. In order to understand value chains associated with sharks the team collect weight and price information for each species of shark landed that day, along with the details of which individuals are selling and buying them. Sales are conducted quickly and sharks often disappear seconds after being offloaded, therefore researchers need to be quick and rely on their good relationships with traders and buyers. Within Sri Lanka shark fisheries are considered zero wastage, therefore the team has to collect price and weight data for the sales of meat, fins, liver, teeth/jaws and skin as well as whole sharks.

Meat and fins are separated for sale on the market side.

Our research team also conduct questionnaires with fishers that are landing to the markets on the subject of their fishing behaviours, attitudes towards sharks and the economics of their recent trip. These surveys are conducted by researchers with the captains of the vessels, often in the wheel-house, and tablets are used to help speed up recording and analysis. By combining data from both types of surveys, as well as interviews with other individuals such as shark traders, we can map out socio-economic reliance on shark resources. This will help us to understand likely impacts of changes in management and policy interventions on a national and international level. It could also offer policy-makers an insight into how fishers see their industry and livelihoods and what is important to them for the future.

Fishers are regularly gone for trips of over 2 months

All images taken by the author. This work is supported by the Bertarelli Foundation as part of the Bertarelli Programme in Marine Science and is conducted in partnership with the Zoological Society of London.

You can follow Claire on Twitter.

 

#ExeterMarine is an interdisciplinary group of marine related researchers with capabilities across the scientific, biological,  medical, engineering, humanities and social science fields.

Find us on: Facebook : Twitter : Instagram : LinkedIn  

If you are interested in working with our researchers or students, contact Michael Hanley or visit our website!