Basking sharks galore...UPDATE

10th May 2007 Although the work of the IWDG is firmly focused on recording cetaceans (whales, dolphins and porpoises) in Irish waters, we do accept, validate and disseminate basking shark records in the same manner as we treat cetacean sightings. We will continue to do so until such time as a national recording scheme is established which can handle these sightings data.


The following is a brief synopsis of basking shark (Cetorhinus maximus) sightings and trends based on records reported to and validated by the IWDG sighting scheme over the last few years.

Despite the often sensationalist media headlines every summer that sharks have been seen around our coasts; Irish waters are home to at least 13 shark species, of which the basking shark is by far the largest. In fact the basking shark is very much at home in Irish waters and indeed areas of the Irish Sea around the Isle of Man are considered to provide some of the best habitat anywhere in the world, for the second largest fish species in the world.



A quick analysis of sightings over the past three years does throw up some interesting trends. For instance the numbers of sightings reported in the following years were:

2004 - 39 records

2005 - 37 records

2006 - 38 records

.....and so far in 2007 up to 10th May we have received 25 sightings, and we're only one third into the shark season. This represents a 200% increase in sightings so far, based on figures for the same period during the previous three years.

Another interesting fact is the strong seasonal trend in the distribution of sightings. For instance, if we take a look at the dates between first and last sightings in the same years we see that there is a strong May-June peak in sightings:

2004: 28th Mar - 4th Sept

2005: 19th Mar - 10th Aug

2006: 18th Apr - 20th Aug

2007: 6th Apr -

You would think that with all the land and boat based watch effort along the south coast, that the Celtic Sea would claim the biggest concentration of sightings. But contrary to the somewhat curious commentary on Mooney Goes Wild 11/5/07 suggesting that once again West Cork and even places like Loop Head, Co. Clare are the best places to observe them; the facts suggest otherwise. Data collated over the years consistantly shows the North coast and North Channel produce significantly more basking shark sightings than other sectors such as the Irish sea, Celtic Sea, southwest and west Coasts.



That said, this is a species that can turn up anywhere, so keep your eyes peeled, especially on those calm early summer days, when you have the best chance of having an encounter with one of the least understood of our gentle giants.

For entensive analysis of basking shark and indeed any cetacean species in Irish waters, you can use the "advanced search" facility on www.iwdg.ie which will enable you interrogate all validated sightings and strandings by species, time frame and location.

We hope you find this facility of value.

Read on for a report on a wonderful encounter of a large aggregation of basking sharks along the west Waterford/east Cork coast last week......

Report 3rd May 2007

IWDG have received a report of the 1st large aggregation of basking sharks this year, with a minimum of 20 sharks off Capel Island area, on 3rd May, reported by Tom Power.

While fishing for Mackeral within 2-3 miles of Capel Island, they initially observed 8-9 basking sharks and then saw other smaller groups of 4-5, and more were seen by others in the area. The sharks which are plankton feeders appeared to be feeding in areas with high densities of sma