Fichefet, J., De Loose, E., Dudley, R., Martin, G., Tully, O., Berrow, S. Assessing the risk of whale entanglement in pot fisheries in Irish waters. Front. Mar. Sci.13, 1749710. (2026). https://doi.org/10.3389/fmars.2026.1749710
A latest research by Fichefet and colleagues mapped the place whales and pot fishing gear are most definitely to overlap in Irish waters, revealing hotspots of entanglement risk and the place conservation efforts could matter most.
Pot Fishing and Whale Entanglement
Pot fishing is a business and leisure fishing technique that makes use of baited cages or baskets, typically made of wire or wooden, to lure shellfish and fish on the seafloor. These traps permit animals to enter simply however make escape troublesome or inconceivable. Compared to massive trawls, which might end result in vital bycatch, pot fishing could seem comparatively innocent.
However, pot fishing is passive. The baited cages sit on the seafloor, and fishers later retrieve them utilizing ropes that join them to floor buoys (often known as vertical strains). Depending on the dimensions of the pot fishing operation, traps could also be set individually or linked collectively in long strings by different ropes known as groundlines.
While the ropes make it simple for fisherman to relocate their cages, these identical ropes create a vertical maze in the water. Large whales can grow to be entangled in these strains, with rope wrapped round their fins, tails, or mouths, particularly in areas the place their feeding grounds overlap with fishing exercise. Entanglement can limit motion, result in critical harm, and typically in the end demise.
Although business whaling protections have allowed whale populations to recuperate and increase, fishing exercise has additionally expanded over time. These simultaneous will increase end result in a growing risk of entanglement for giant whales.
Whales in Irish Waters
Large whales play a key function in the setting. In the coastal waters of Ireland, whale populations are dispersed throughout the island. So far, 26 totally different cetacean species have been recorded in Irish waters, however the three whale species that dominate are minke, fin, and humpback whales. These whales use the Irish waters to feed; nonetheless, the energetic fisheries in the Irish waters create an overlap of whales and gear.
Understanding Entanglement Risk
Previous research have assessed whale entanglement risk in Irish waters, however many have ignored a key issue: small boats. Boats much less than 12 meters in size make up about 85% of the Irish fleet, and they usually use pot fishing gear. However, in contrast to bigger vessels, they aren’t required to hold Vessel Monitoring Systems (VMS), which makes their exercise more durable to trace.
To overcome these gaps, Fichefet and their workforce mixed a number of datasets, together with bigger vessel information and different landings info, to estimate fishing effort. Following the work of earlier research, they then calculated the “risk of entanglement measure (REM).” The REM index in the end identifies the areas the place whale presence and fishing exercise overlap most strongly and may result in entanglement.
So the place are the whales?
Using whale sighting information from 2005 – 2022, researchers discovered that the best whale densities occurred off Ireland’s south and southwest coasts for humpback, minke, and fin whales (Figure 1). Minke whales had been discovered to be probably the most considerable. While all three whale species had been current year-round, the height seasons differed by species. Humpback whales peaked July – September, minke whales peaked May – July, and fin whales peaked September – November.
And the place is the fishing taking place?
The researchers then checked out each fishing effort, measured as hours spent fishing per yr, and accessible density of pots per kilometer squared. Between each approaches to quantify fishing, the outcomes agreed that effort was highest in Ireland’s north coast, east coast, and southwest coast (Figure 2).
Mapping Entanglement Risk
By combining whale density with fishing effort, the REM index revealed clear hotspots of entanglement risk. Ireland’s southwest coast confirmed the best total risk, significantly for boats over 12 meters in size (Figure 3). Minke whales had a broader risk distribution, stretching into the northern and jap waters in comparison with the opposite whale species. Humpback whale risk was concentrated in the southwest and south, and fin whales confirmed elevated risk alongside the south coast. Similarly, for vessels underneath 12 meters in size, the trends had been very related (Figure 4). Overall, the areas of highest entanglement risk intently matched areas with each high whale density and high fishing exercise.
Implications for Conservation
Importantly, the research discovered that areas with high REM values typically overlapped with Areas of Interest (AoI) recognized for potential Marine Protected Areas (MPAs) for cetaceans (Figure 5). Entanglement risk was highest in late spring and summer time, with the southwest coast of Ireland rising as a precedence space for potential mitigation methods. These outcomes point out that entanglement risk must be a key consideration in future MPA planning. By mapping the place whales and fisheries overlap, this analysis offered a number of instruments that can be utilized to information smarter and more efficient conservation methods in Irish waters.
Acknowledging Data Gaps
Nevertheless, like many large-scale ecological research, this work relied on some opportunistic information, which does introduce bias. Whale sightings are more common in coastal and well-traveled areas, and offshore areas stay under-sampled. Because fin whales floor much less incessantly, they could be more durable to detect and could also be underreported. At the identical time, humpback whales have been reported to outlive some entanglements, in contrast to the smaller minke whales. In addition, Ireland presently lacks a post-mortem program to find out trigger of demise in cetaceans, and the entire fishing effort, particularly from smaller vessels, is probably going underestimated.
Despite these limitations, the research highlights the growing worth of citizen science and opportunistic sighting information in marine analysis in addition to alternatives to reform fishing efforts to gather significant information.
Cover image is a humpback whale breaching in the Hawaiian Islands Humpback Whale National Marine Sanctuary. Photograph was taken by Stan Butler and obtained from the NOAA Public Domain Library.
I’m a Ph.D. Candidate on the University of Connecticut–Avery Point learning the marine carbonate system in the Arctic Ocean. My analysis focuses on biogeochemical adjustments occurring within sea ice because the Arctic continues to heat. Outside of my analysis, I get pleasure from mountain climbing, working, aerial gymnastics, paddleboarding, touring, and spending time with household and associates.
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