Friday, 20 September 2013

Dolphins galore!

How DO you count cetaceans when they only come to the surface irregularly, and move around a lot?

I remember reading one of Cliff's posts about a month ago where he described a super-pod of dolphins as covering 4 square kilometres. I thought no more about it until today, when we came across huge numbers (for us, anyway) of Common Dolphins just about a mile out from the "Lollipop"  outside the entrance to Milford Haven. Everywhere we looked were pods of dolphins, some comprising a few individuals, others well over a dozen. Looking at some of the video that we took on our camera, I now realise that at some stages we had six dolphins just on each side of the bows of our RIB, cresting along.

I suspect that there were well over a hundred individuals, and perhaps twice that, alternately feeding (the Gannets had a good time) and playing (sometimes with us). Slightly more accurately, I estimate that, at the peak of over an hour of activity we could see groups of dolphins easily 500 metres in any direction: a (square) kilometre of dolphins!

(Just for the record, we found this massive grouping at around an hour before low tide today,before the tide started to flow North outside the Heads of the Haven).

Thanks for this Sash... and you have hit the nail on the head when you ask how do you count dolphins? The simple answer is we can't accurately count dolphins, its impossible once you get more then a handful. Its what makes a monkey of those who talk about absolute abundance and techniques like distance sampling!
The only way we have of knowing how these animals are faring is getting out there regularly and systematically  monitoring the area of sea around our coast. In doing so we can detect patterns of behavior  breeding success and trends which should make it possible to notice problems and hopefully then analyse and try and solve them. We have been trying to do this for over ten years at Sea Trust and postings such as yours help to fill in the gaps. If only everyone who went out in boats and saw cetaceans would do the same we would know a lot more!
A general word of caution though: Please do not chase or harass animals, make sure to follow the Pembrokeshire Marine Code which you can link to via this blog, (see: Quick Links)