Monday, February 25, 2013

For what porpoise?

We walked the length of Sandwich Bay this weekend on the Beached Bird Survey. There were few bird carcasses to record and little evidence of oil pollution. Well and good. It was bitingly cold in the NE wind, so I'm glad we walked the route from Prince's Golf Club towards Deal and not vice versa, with the wind and sleet beating at our backs rather than on our faces.

Sandwich Bay in winter is a rather forbidding place. Flat and pretty bleak, there's no hiding place from whatever the weather wants to throw at you. Apart from the usual flotsam and jetsam of the tideline; plastic, seaweed and lots of whelk eggsacs blowing about in the wind like tumbleweed, there was little to see on the shore, until we came across this.


It was once a harbour porpoise, a protected marine mammal. This carcass was about 2½ feet long.  

Harbour porpoises are delightful, endearing mammals, which feed on small fish, like sprats (as do I and buy them from the local fishermen on Deal beach). The word porpoise is derived from the Latin porcus, pig and piscus, fish. Although I don't see the resemblance myself.

Natural History Museum.Taken in 2007 by Hy'Shqa on Flickr. 
Used under a CC BY-NC-ND 2.0 license. Original here http://tinyurl.com/akq5sr7

It's a species, as its name suggests, of coastal waters, found in the cool North Atlantic, including the UK and northern European coastline.

Range map for harbour porpoise from Wikipedia. 
Used under a Creative Commons license. Original here http://tinyurl.com/alx3odk

Here's what an intact dead harbour porpoise looks like. This one was washed up on the US north eastern seaboard so it's a harbor porpoise.

Harbour porpoise washed up on the US coast (I believe) in March 2012 by chester08057 on Flickr. 
Used under a CC BY-NC-ND 2.0 license. Original here http://tinyurl.com/b4jvblq

And here's the Sandwich Bay porpoise; sans flippers, sans dorsal fin, sans tail fin. It's also had its belly cut open; the intestines were hanging out on the other side. I don't need to be a CSI to know this animal has been intentionally mutilated. I can only hope it was post-mortem.


I suspect this was done at sea and the body tossed overboard. Here are close ups of some of the injuries: sliced off dorsal fin & tail fin.



I'd not heard of marine mammals being mutilated like this, but found a reference to exactly this type of incident on the Dutch coast (Wietse Van Der Werf, 2009 writing for Sea Shepherd). The mutilation is believed to be by fishermen to hide evidence of the illegal killing of harbour porpoises; the cutting and gutting being a crude attempt to make the carcass sink to the sea bed. As over a 100 similarly mutilated corpses were washed up on the Dutch coast, this doesn't seem to be very effective method of hiding illegal activity.

We don't make it easy for marine mammals. Not only have we poisoned their food with toxic chemicals. We overfish reducing available food. Plastic in all shapes and sizes pollutes the sea. We dredge the sea bed and destroy habitats. And we're noisy. The Channel is one of the busiest shipping lanes in the world. Porpoises are social animals and hunt using sonar. How do they cope with the cacophony of sound in the Channel? As if all that is not enough they might also be injured directly by boats and other leisure craft.

And of course, they may get entangled in fishing nets. A porpoise needs to come to the surface to breathe so can drown trapped in nets. If accidentally caught, the correct procedure is to cut the animal from the net carefully and release it unharmed back into the sea. Not, cut up the animal, mutilate it and then chuck it back. The more responsible thing to do is to fit nets with sonic pingers to warn animals of danger so they don't get caught in the first place.


I believe the Sandwich Bay porpoise either drowned and was then mutilated to hide the fact it was by-catch, or, to save damaging the nets, was killed and mutilated. This is to keep profits high and prevent discovery. Whatever happened, it stinks.

How do I know the fish I eat is being caught sustainably? How do I know how fishermen behave if they accidentally capture a porpoise? Even a short walk down the coast indicates we use the sea as a big dumping ground for all manner of rubbish. Out of sight, out of mind.

In 1991 the UK signed the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas; ASCOBANS. Signatories oblige themselves to protect the habitats of small cetaceans, collect data for scientific studies, decrease pollution and spread information. Is this agreement being enforced?

So what can I do to make a difference for porpoises?
1. Buy fish only from sustainable fisheries. Make informed decisions. Use the Marine Conservation Society buyer's guide

2. Don’t pollute the sea. I don’t drop litter but there's no lack of litter for me to pick up. Take a bag when walking on the beach. Apparently plastic bags can look like squid so it’s good to get these items off the beach. It's a tiny effort compared to the problem, but if we all did it…

3. Support marine NGOs. Join the Marine Conservation Society (MCS) and support Sea Shepherd, Hugh's Fish Fight, British Divers Marine Life Rescue...

4. If you find a live stranded cetacean, call for help. The Coastguard is on 112. The British Divers Marine Life Rescue Hotline is 01825 765546 during office hours, 07787 433412 out of office hours. Put these numbers in your mobile phone. Note the place, state of the tide and any injuries you can see without getting close. The rescue team will tell you what to do. Always make sure your mobile is fully charged before taking a walk down the coast!

5. Report dead cetaceans to the Coastguard. Animals can be autopsied to find cause of death. I didn't know this when I was out on Sandwich Bay so reported it today. And I can report they emailed me back within minutes. You can rely on HM Coastguard. The email for reports is row@mcga.gov.uk or your nearest CG station.

6. You can report any marine mammal sighting online. The Marine Sightings Network is pretty comprehensive (and not just for cetaceans). There's also the Natural History Museum Stranding Project with reporting info here (although I'm having a dastardly time trying to read the form with Adobe!). And in that regard it's wise to learn some ID skills. A camera is indispensable of course.

7. If you do go out to sea to watch marine mammals, do so with respect. Check trip organisers follow an approved code of conduct.

8. Raise awareness & celebrate the 11th International Day of the Baltic Harbour Porpoise on May 19 2013.

Bibliography
ASCOBANS webpage. Species leaflet here. How to make a difference here

Wietse Van Der Werf (March 17, 2009) Fishermen Eager to Hide Evidence of Illegal Porpoise Killings. Sea Shepherd International.

Arne Bjorge and Krystal Tolley (2008) 'Harbor porpoise, Phocoena phocoena' in Encyclopedia of Marine Mammals. Academic Press, 2nd Edn. Pages 530-32 available on Google Books here.