May is for minke whale…

Almost a year ago our then MSc Marine Mammal Science students were treated to an impromptu necropsy of a minke whale that washed ashore almost at our door step in St Andrews….. below is what happened this year…This whale arrived a little too early while students were still in the middle of exam preparations but such a great opportunity was not lost on them…..so Pablo and Lacey report on whale stranding 2.0:

On May 5th, the students of the MSc Marine Mammal Science were able to assist the Scottish Marine Animal Strandings Scheme (SMASS) team with a minke whale necropsy. A juvenile female of almost 6m in length had stranded and died on the sandy beach on the southern edge of Tentsmuir forest, across the river Eden from West Sands and St Andrews.

Minke whale and necropsy team on the beach (photo: Sanne Bakkers)

Getting to the location was a little tricky, with cabs and cars making their way along back country roads to find the location with beach access on foot. There was some thought that the minke whale might be the same one that had live-stranded in the nearby Firth of Forth recently, and had been re-floated successfully by the BDMLR strandings response team. It was understood that the previously rescued whale had a unique hole in its pectoral fin, so it was a matter of flipping this dead whale over to check. Teams of tuggers assisted by diggers set to work and pulled on ropes to try and roll the whale over. It soon became obvious that this whale had its fins intact, so it turned out to be a different whale.

Moving the whale (photo: Laura Palmer)
Minke whale flipper (photo: Lauren Arkoosh)

The near perfect external state of this whale was surprising (and appreciated!). We got the chance to behold external features such as the short baleen plates, the groove for the internally located reproductive organs and the consistency of the fins. After taking external measurements the SMASS team then proceeded to slice open the whale: underneath the dark skin the white blubber layer appeared and was measuerd to be less than 2 inches thick. Next, the layers of dark red muscle below were removed. As the necropsy progressed, samples were stored in containers filled with formalin or ethanol and labelled, their destinations being different labs around the world.

Students getting into the whale – quite literally (photo: Laura Palmer)

As Andrew (the lead vet)’s knives were revealing organs, he was naming them for us. It was fascinating to watch the inner workings of a whale and the important traits for whale diving physiology. The colour of the muscle, rich in myoglobin, was relatively light for a whale but darker than anything we had ever seen before [the intensity of colour in the muscle indicates how much myoglobin there is which relates to how long a species dives –  minke whales don’t dive for that long or deep]. As we moved to the organs in the digestive system, we started to note quite a lot of parasites: anisakis (nematodes) and Bolbosoma sp. (thorny-headed worms) in the digestive tract, and liver flukes (a type of parasitic flat worm).

They look like spaghetti….. nematodes from the whale’s stomach (photo: Sanne Bakkers)

While we were holding surprisingly heavy whale ribs and feeling the –still very warm- insides of the whale, a sneaky grey seal arrived on the beach to check us out from a distance. The seal stole the show for a couple of minutes – a live marine mammal beats a dead one any time…..But soon we were back to the inner workings of the minke whale: the heavily congested lungs (filled with fluid) indicated that the whale had stranded alive (and laboured to breath as its weight squashed its lungs), but the cause for the actual stranding was not easily discernible……. We were curious about what could have caused an apparently healthy looking individual to strand alive (this is particularly relevant to us as we were preparing for exam questions related to potential threats to marine mammals for our MSc conservation and management course). Perhaps opening the head would reveal an inflammation in the brain or other compromising injury. Unfortunately we could not stay until the end of the necropsy to find out, but before having to return to books and exam revisions we got to measure the small intestines: all 30 meters thereof! Apparently that’s short for a baleen whale, but it surely looked impressive to us to see the guts laid out on the beach. We also noticed that the stomach and intestines were empty of food remains but quite full with parasites….. potentially a serious burden for the whale and possibly a contributing factor to its demise.

Tug of war with intestines…. whale guts are long! (photo: Lauren Arkoosh)

This experience was a great chance to bring to life many of the subjects we have studied over the past 9 months, from physiology to causes of death and whale conservation. The good state of the animal, the expertise of the SMASS team and the whale’s proximity to St Andrews all aligned –almost suspiciously- to grant an afternoon of great outdoor learning. We all left feeling more aware of the active role we are called to play in marine mammal research and conservation…..