Mass stranding of common dolphins on Achill Island, Co. Mayo UPDATE

25th Apr 2013

Update 25 April 2013

IWDG welcome the post-mortems carried out at the Athlone Regional Veterinary Laboratory of the Department of Agriculture, Food and the Marine on the common dolphins stranded on the northwest coast in January/February this year. The commissioning of post-mortems by suitably qualified vets has been a recommendation of the IWDG for many years and without this key information the cause of death of cetaceans washed up on the coast cannot be determined. IWDG congratulates the NPWS for taking this initiative.

Although IWDG have not yet seen the reports it is clear that the dolphins were drowned in fishing nets.  Presence of lesions on their bodies and fish in their stomach confirmed they had been caught in pelagic trawls. A large number of Irish and foreign vessels fish pelagic species in Irish waters but IWDG believes it was the large foreign freeze trawlers that were responsible for this bycatch. The large Irish vessels were fishing off north Scotland during March and the smaller vessels were sheltering from the storms hitting Ireland during that period. 

All fisheries in Europe with vessels larger than 15m are required to carry independent observers to quantify the bycatch of cetaceans and identify those fisheries with high bycatch rates. This Bycatch Regulation 812/2004 sets out the number of vessels in the fishery to be monitored and fishing areas where observers must operate.  Fisheries with high bycatch rates will be required to adopt mitigation measures such as the use of acoustic deterrents.

The Irish pelagic fleet have been collaborating with cetacean bycatch studies over the past two seasons with no cetacean bycatch reported. There is no information available on the bycatch rates of these large foreign vessels fishing in Irish waters and the IWDG wish to see the Irish government request all foreign vessels of a certain size and in certain fishery be compliant with this regulation.  

The Irish government is required to protect all species of cetacean in Irish waters and if a fishery is identified which has a high bycatch rate then all steps possible must be taken to reduce this bycatch to minimal levels. The problems of cetacean bycatch are international but Ireland must put pressure on the EU to ensure all EU fleets are compliant. 

Bycatch monitoring is difficult and bycatch a rare event but by systematically monitoring key fisheries those with a bycatch problem can be identified.  Failure to do this is in the opinion of the IWDG against the legal obligations of the Habotats and other EU Directives.

IWDG published a Commercial Fisheries Policy Document in 2006 oputl;ining this and other initiatives intended to reduce the impact of fishing activity on cetaceans (http://www.iwdg.ie/downloads/Commercial%20fishing%20policy%20document.pdf)

We hope NPWS will continue to use the services of the veterinary labs in the future to identify causes of death of future unusual stranding events as identified by the IWDG Cetacean Stranding Scheme.

 

Dr Simon Berrow

IWDG Executive Officer

 

Update 10 February 2013

Over the last ten days have been unprecedentednumbers of  cetaceans stranded in Ireland and the biggest number, by far involves common dolphin Delphinus delphis. Between 30 January 2013 and 8 February 2013, a minimum of 21 common dolphins were found dead on the shores of counties Mayo (16), Kerry (3), Donegal (1) and Waterford (1). In Mayo, the principle stranding sites were the Mullet Peninsula (6) and Achill Island where eight animals are recorded although local reports suggest that as many as 13 may have actually washed ashore. To put this in some perspective, we can compare these numbers to the same period in 2012 (which was the year with the highest total number of cetacean strandings on record) when two common dolphins were recorded as stranding, in 2011 there were four records received and in 2010 no common dolphins were recorded between 30 January and 8 February.

The number of common dolphin strandings recently is worryingly high. It is evident that all of the animals washed/blown ashore were already dead and were in variable condition. It is remarkable to have so many of one species stranding, either singly or in small groups over such a short space of time at relatively localized locations. In the case of one common dolphin, it was found on 5 February on Cuas Crom, a small beach near Caherciveen, Co. Kerry in the company of two dead pilot whales Globicephela melas. One would also have to wonder at how many other dead cetaceans, and especially common dolphins remain unrecorded due to either washing ashore in remote/inaccessible locations or simply not washing ashore at all.

As of now, we have a lot of questions – is the current peak of strandings over? what caused it?, can it be prevented from happening again? In recognition of the unusual nature of current stranding events in Ireland, the National Parks and Wildlife Service (NPWS) has recovered several stranded specimens for post-mortem examination and tests are ongoing to determine cause of death with results available within the next couple of weeks.

Mass stranding of common dolphins on Achill Island, Co. Mayo

Over the last two days at least eight common dolphins Delphinus delphis have been found dead on the beaches of Achill Island, Co. Mayo. Unconfirmed reports suggest that there is another dead dolphin on a nearby island and another may have been buried on the beach.

IWDG don't have full details to hand as yet but photos sent to us by local people show most of the dolphins died very recently although there are no reports of any live strandings there over the last few days. So far, dead common dolphins are confirmed at Keel Beach, Keem Beach and Dookinella. While there are occasionally live strandings involving groups of dolphins, it is very unusual in this country to see this number of dead dolphins washed ashore over a 10km area. Updates will be added here as and when we have further information.

Mick O'Connell,

IWDG Stranding Officer