During my time in British Columbia this summer, I attended a training event on marine mammal entanglement, strandings and necropsies at the Department of Fisheries and Oceans Canada.
Sadly, marine mammals all too frequently get themselves tangled up in our rubbish that drifts in the ocean. Seals and sea lions get their head stuck in the loops of plastic wrapping, such as beer can rings or packaging straps. Larger whales can get fishing nets (including the buoys) wrapped around their mouths, fins and tails. It is thought that up to 80% of the plastic marine debris in the ocean is from land-based sources and the problem is getting worse. Disentangling marine life is important, but it wise to leave this to the professionals. Whales are large creatures and sea lions have sharp teeth, and they are likely to be pretty unhappy! There are many people in the UK who are trained to disentangle marine life and so the best thing to do is report it to the British Divers Marine Life Rescue. In British Columbia, it is the job of the Marine Mammal Response Network.
Marine mammals can strand themselves on the beach, sometimes as individuals because they are lost or sick, but sometimes in large numbers (see a previous blog on mass stranding http://www.naturebureau.co.uk/news-blogs/mass-strandings.html). When a whales strands rescue teams will often jump into action and head to the beach. The BBMLR in the UK do an amazing job and successfully return countless cetaceans and pinnipeds to the ocean every year.
Sadly, there is not always a happy ending. Sometimes marine mammals wash ashore already dead, or die whilst stranded. In these cases, a necropsy may be carried out in order to learn more about the cause of death. This gives scientists a greater understanding of what is happening in the environment and how we can help to protect their populations in the future. In the case of marine mammals, necropsies can happen in the lab if the animal is small, like a seal or a porpoise. But if the animal is large, like a sperm whale, sometimes it might have to be done right on the beach with just samples taken back to the lab! Ever tried lifting a sperm whale?! Not an easy task!
I was lucky enough to be trained on assisting in necropsies. We performed the training on a river otter (OK so not a marine mammal but it was a bit more manageable than a sperm whale!) that had died in 2013 and been in the deep freeze since then.
We were able to confirm that the death was the result of a blunt force trauma on the abdomen that had resulted in a large amount of internal bleeding. Conducting the necropsy was incredibly fascinating and insightful, and we were lucky to conduct ours outside in the fresh air. It is certainly not a task for the squeamish or faint-hearted!
This was an excellent training event and something that I hope to get more involved in on my return to the UK in August.
For more information on what to do if you see a marine mammal entangled or live stranded, please contact the British Divers Marine Life Rescue: http://www.bdmlr.org.uk/index.php. Rescue hotline: 01825 765546 during office hours (07787 433412 out of office hours). Remember to make a note of the place, the state of the tide and any injuries you can see without getting close.
If you come across a dead marine mammal or want more information on necropsies, please go to the UK Cetacean Strandings Investigation Programme: https://www.zsl.org/science/research/uk-cetacean-strandings-investigation-programme-csip