Every year since 2011, stranding of whales, dolphins and porpoises on the Irish coast have become extremely high compared to historical levels so that we now record twice as many as this time 10 years ago. Unfortunately, it feels like Groundhog Day now – we say the same thing every year and mostly it feels like not many people care
One live stranded sick whale on a beach will get more attention than 50 dead dolphins – and we are nearly at that number already.
It is only the 9th of February and so far we have 43 strandings reported this year which is the highest ever recorded, and already 2018, 2017 and 2019 are the years (in order) with the highest numbers of strandings in Ireland.
The high numbers are almost exclusively due to massive increases in numbers of dead common dolphins washing ashore during January and February mostly. For example, before 2011, it would have been normal to have around 30 common dolphin strandings per year – in the last few years, that figure has risen to around 110!!!! Based on some research in France, it is estimated that less than 10% of dead animals that die at sea may wash ashore and be recorded so that 110 figure may represent c.1000 dead animals.
We already have 20 common dolphin strandings in 2020 and February has become a bad month for this species so who knows what the next few weeks will bring.
Common dolphin with pectoral and part of tail fin cut off, Garryvoe, Co. Cork, 8 Feb 2020. Amanda Whyler
With a number of dead dolphins showing typical signs of bycatch in fishing net (broken beaks, cut fins etc) it is interesting to note that most strandings are currently in Cork and Kerry. A look at AIS vessel finder shows that much current fishing effort off our coast is also off the southwest, not by Irish vessels but mostly large French, Spanish and Dutch vessels. The owners of these vessels would say they are not finding dolphin bycatch an issue, and indeed, observers onboard a percentage of vessels are recording little if any bycatch of cetaceans. Yet, the signs on our beaches are saying something different – 3 dead dolphins in just over a week on Derrynane Beach in Co. Kerry for example, at least two of which were juvenile. Post-mortem reports on common dolphins in Mayo in 2014 did show a link to bycatch and as some of the dolphins had been feeding on horse mackerel, the inference is a connection to that fishery.
There is a new twist to this story in 2020 as apart from dead common dolphins washing ashore, there are unusual numbers of live strandings, again in the southwest. A single common dolphin live stranded at Coumeenole, Co. Kerry on 31 December, five at Cloghane, Co. Kerry on 2 February, two at Ventry, Co. Kerry on 7 February, eleven at Cloghane (again) on 7 February and two at Smerwick Harbour, Co. Kerry on 8 February. In recent years, the Marine Institute and NPWS funded a necropsy scheme to look at the causes of death in common dolphins, striped dolphins and harbour porpoises. This scheme ended in December 2019 so currently, no animals are removed for post mortem examination. After nearly ten years, it now seems that what was, at the time, an unusual spike in common dolphin strandings has become an unacceptable ‘norm’ and judging from the first 5 weeks of this year, may even be getting worse.
Mick O’Connell,
IWDG Strandings Officer