Collaboration is key to reducing whale entanglements in Scotland
An entangled sub-adult female minke whale off Bressay, Shetland
Research published last month shows the extent of whale entanglements in fishing gear around Scotland and has identified potential solutions to reduce entanglements in the future.
Entanglement is a global problem and is the single largest cause of death for minke and humpback whales in Scottish waters. The extent of the issue was not previously well understood, but a ground-breaking study run by the Scottish Entanglement Alliance (SEA) bought together government, academia, NGOs and the fishing industry to better understand the impacts and risks of entanglement in creel lines in Scottish waters.
Commercial creelers from all around the Scottish coast were interviewed and their contribution allowed researchers to better understand the nature and extent of entanglements in Scotland’s waters.
This information was analysed alongside sightings and strandings data from the long-term data collection programs run by HWDT (Whale Track and Silurian) and our colleagues at Scottish Marine Animal Stranding Scheme (SMASS), Whale and Dolphin Conservation (WDC Shorewatch), British Divers Marine Life Rescue (BDMLR), Sea Watch Foundation (SWF), and Cetacean Research and Rescue Unit (CRRU), and the distribution of creel fishing effort was assessed using data collected from HWDT’s research vessel Silurian.
The analysis estimated six humpback whales and 30 minke whales become entangled in creel fishing ropes in Scottish waters every year.
The analysis of data from Silurian showed very low densities of humpback whales in the waters off western Scotland, but the opportunistic sightings data suggest numbers are increasing. The estimated number of annual humpback whale entanglements also shows an increasing trend.
The findings have been published in the journal Endangered Species Research (https://doi.org/10.3354/esr01214).
“There is now a legal obligation in Scotland for fishers to report entanglements, which will improve our understanding of the issue. Our current understanding of the extent of entanglements in Scottish waters only became apparent through this study and the valuable contribution made by the fishermen who participated. This collaborative approach means that we now understand so much more about how entanglements occur, which has led us to be able to develop strategies for how to reduce entanglements in the future. There are many cases globally where the problem of marine animals becoming accidentally caught in fishing gear is very hard to solve. But here in Scotland, we can see a way forward, and the key to our success is working together with fishers.”
As well as estimating the number of animals that may become entangled, in collaboration with the fishers, the study also identified some possible solutions. A high proportion of entangled whales had become caught in the groundline, the rope that links creels together on the seabed. The groundline is usually made from rope which floats, and can form arches in the water between creels which basking sharks or whales can get caught round their mouths, flippers or tails.
If the groundline is made of rope which sinks rather than floats, it will lie on the seabed, and will not pose an entanglement risk. Whale and Dolphin Conservation (WDC) are now working with the fishing industry to conduct trials of sinking groundline in Scottish creel fisheries to understand if this is feasible for fishers and what benefits it could have for the marine environment and reducing entanglements in Scotland.
“It’s great to see Scotland’s fishermen are at the forefront of understanding and addressing the issue of marine animal entanglement and we hope to continue the collaborative approach in partnership with government, NGOs and researchers. We really want to trial solutions, and look forward to the next stage in this work.”
HWDT are proud to be part of the Scottish Entanglement Alliance and we continue to work with our partners to better understand the threat of entanglement.
We’d like to extend a huge thanks to everyone who contributed to this work from the fishers who took the time to talk to SEA to our supporters and reporters who contributed to our data collection over the past 30 years. Together, we will continue to work towards healthy Hebridean seas for whales, dolphins, porpoises and people.