Hello and welcome to the 3rd part of this webinar series on non-captive marine mammal medicine in the UK. In the following two talks, we're going to discuss cetacean response with a focus on dealing with smaller cetacean species, such as porpoises and dolphins. Whale strandings are even more challenging and complex and are for the moment outside of the scope of this talk.
If you are called to attend a stranded whale, we suggest you call our hotline for advice as these events attract a lot of public and media attention and hence there is some degree of pressure to ensure that you are making the right decisions. So now I can introduce the second scenario. So here, BGMLR have called and asked for assistance at your local beach where a dolphin has live stranded.
They have a team of BGMLR medics on the way, but they require a vet to attend to. So in this first talk, we're going to look at why cetacean strand and which species strand more commonly in the UK. We'll also discuss the role of the veterinary team at strandings and health and safety aspects of the work too.
In the second talk, we'll go into how to perform an assessment, the decision-making process, how a refloat is carried out, and also how to perform euthanasia. And this is all with a focus on smaller cetacean species. Firstly, just to cover what a cetacean is in case there is anyone who isn't sure, Cetaceans are animals belonging to the older Cetacea, and this consists of porpoises, dolphins and whales.
These are actually divided into two groups, the mystic City, which are the baleen whales, like the minke whale illustrated at the bottom of the slide here, but also includes species such as the humpback, fin, say, and blue whales. And the other group are the Adontota, which are the toothed whales and actually include the porpoises, and dolphins as well as whales like the sperm whale and beaked whales. So on the next few slides, we're going to look at some of the species we see more commonly in the UK.
Now there are 90 cetacean species globally, and about a third have been observed in UK waters, but obviously we'd be here quite a long time if I spoke about all of them, so we'll just focus on a handful of the more frequently seen ones. The first species we commonly see is the one on this slide here, the harbour porpoise, and they are generally quite a shy species and they're found alone or in small groups, and they're found all around the UK coast. They only grow to about 2 metres long, so they're probably the smallest cetacean species that we see here.
And they're also a coastal species which is used to navigating shallow water and tidal areas, so most often they will strand because of a health problem rather than a navigational error. Sadly, they're also quite frequently the victim of bottlenose dolphin attacks and can strand with some really severe injuries caused by those bottlenose dolphins, raking them with their teeth and slamming into them and hitting them. Next we have the common dolphin, which is probably the species we see strand most often here in the UK.
They grow to be about 2.5 metres in length and can travel in sometimes really large groups. They're frequently found in the Western English Channel, the southwest of England and Ireland.
They are a pelagic, so that means a deep water species, and they can frequently get themselves stranded in tidal river systems, for example, despite being in good health. This is one of our species which tends to be more susceptible to mass stranding. So in June 2008/70 animals were rescued by the combined efforts of BDMLR and local emergency services in the Fowl estuary in Cornwall.
Two other dolphins were put to sleep and a further 24 were already deceased when aid actually arrived. So this was the largest common dolphin mass stranding on record for the UK and it was unfortunately linked to a military exercise that was ongoing in the area at the time. Then we have the bottlenose dolphin, which is a much larger dolphin growing up to 4 metres in length and weighing hundreds of kilos.
You will probably recognise this species as they've been very frequently used in film and television and are a very popular species to keep in captivity in dolphin area. They are found in resident populations in coastal waters, such as the Moray Firth, Cardigan Bay, and the southwest of England, with also some transient populations found living offshore. Again, because they are typically a coastal species, they tend to strand more due to ill health.
The white beet dolphin grows to around 3.1 metres long and is found mainly off Scotland in the Atlantic seaboard of Britain and Ireland, and also in the northern and central North Sea. So they typically strand around Scotland and the northern North Sea coastline.
And then we move on to the long-finned pilot whale, which is moving into the larger of the species that we can successfully refloat using our specialist pontoons. They can grow up to around 6 metres long and weigh a couple of tonnes. They're found in the North Atlantic and move into British waters seasonally.
They're also well known for having incredibly strong social bonds and hence are a species at quite high risk of mass stranding. For example, a sick individual may strand due to illness, and then the rest of the pod will stay with them and end up stranding themselves too just to avoid actually having to leave each other. In recent years, BDMR has responded to several pilot whale mass strandings, mostly up in Scotland.
And those have probably been some of the more challenging situations that the charity has had to respond to. And finally, the last species I'm going to mention here is the minke whale. They're a baleen species of whale and can grow to 8.5 metres long.
They're found in the North Atlantic, the northern North Sea, and the western approaches to the English Channel. They are known to hunt in coastal environments, but they can get caught out by the tide, and refloats in the past have actually been possible in some cases. So that was only 6 out of the very large number of species that we do see in UK waters and which BGMR will respond to as live strandings.
However, there are many more, and they do include some of the largest species on Earth, such as sperm whales and fin whales. And you can see there's a fin whale photographed here, which stranded on Valentine's Day in 2020 in Cornwall, and it was actually 19 metres long. As I said earlier, our response to animals of this size differs greatly to that of the smaller species.
And for the purposes of this webinar series, we are going to stay focused on the response to the smaller species. But you can, however, quite clearly see that our options for an animals such as the one in this photo are going to be very limited. And good communication with the public and media are of critical importance to help people understand this.
Very often people will ask why they can't be dragged back to the water by vehicles and such. But without the understanding that firstly these animals are likely to already be unwell, hence why they're stranded, or the effects of the stranding itself on their body will mean they're already irreparably damaged. That's without of course even mentioning the severe trauma and stress that would be caused by trying to toe these animals and also the immense danger that anyone would be facing trying to attach anything to a tail this big where it could literally just crush you.
It's just, it's just very difficult for people to accept that there is little that we can do, particularly when even humane euthanasia is extremely hard to achieve. And hence, why I guess that the role of the vet at these strandings is such a challenging one. So, anyway, moving on to discuss why cetaceans live strands in the first place.
So strandings can be very roughly divided into two groups, one's where the animals strand in a healthy condition and ones where they strand in an unhealthy condition. I'm sure that you can all look at these two photos and determine which of these common dolphins is looking in better condition than the other, even ignoring the very obvious old injury the dolphin has to its dorsal fin in the bottom photo. Now body condition is not always this obvious and can in fact be really difficult to judge, but we will discuss that more in the next talk.
For now, just notice how well rounded the dolphin at the top is and how sunken the dolphin below it is, particularly looking at the muscle ventral to the dorsal fin where you can see the concavity there. Firstly, let's look at why healthy animals might strand. So what on earth would drive a healthy dolphin to end up stranded on land and to probably be in the most vulnerable position that it will ever be in?
There are actually many reasons as to why this might happen, and I've listed some of the more common ones here. So first we have animals that make navigational errors, which results in them stranding. Some will navigate by following the Earth's geomagnetic contours.
And when these cross a beach or an outcrop of land, for example, they can accidentally strand. Others may get caught out by gently shelving beaches where their echolocation is reputed to not work as effectively or even by falling tides, particularly when they've entered a tidal river system. Some simply get lost in areas unfamiliar to them or get distracted by chasing prey and accidentally ending up in shallow water.
Other times strandings of healthy animals can occur for social reasons. I mentioned earlier mass stranding sometimes occurring when one sick individual strands and the other healthy pod members follow, for example. Of course it's not always a sick individual that's the reason for the stranding, but it's the fact that they stay together as a group, which means that they all end up in trouble.
And the final reason that I've listed here is the very broad category of disturbance. This will mostly be due to human activity which might scare animals onto land or into shallow waters, or perhaps noise will drown out their communication between each other, for example. And then there are animals which strand due to ill health of some sort, and this is probably the more common reason for cetacean strandings overall.
Some sort of health issue leads to the animal, becoming weakened and disorientated, and hence you know, more likely to strand. These issues commonly include infections, trauma and malnutrition, but I'm also going to mention gas bubble disease and net entanglement as issues to be aware of. Of course there could also be a combination of these factors involved too.
So over the next few slides we'll go through each of these in turn. Serious infections are commonly found as a primary reason for cetacean strandings. They can suffer from bacterial infections caused by species such as E.
Coli and salmonella, and the others that I've listed here leading to pneumonias, peritonitis, hepatitis, gastroenteritis, meningitis, and septicaemia. The bottom photo is actually the brain of a striped dolphin, and you can see the cloudy cerebrospinal fluid indicative of a meningitis. So this was caused by a Bruucella setti infection, which is a common finding in striped dolphins in particular, and a good example of a potentially zoonotic disease that these animals can carry.
The top photos from a harbour porpoise with a severe lung worm infection illustrating the types of parasitic infections that cetaceans can suffer from. And then we will see animals with viral infections too. Morbilla virus is worthy of note for having caused many epidemics in different cetacean species worldwide.
For example, in bottlenose dolphins on the Atlantic coast of the USA in the late 1980s. It's not so much associated with live strandings, but they have occurred and generally it causes encephalitis and pneumonias, with a marked immunosuppression. A cetacean can suffer trauma as a result of a whole host of reasons.
For example, intra-specific trauma, where a member of one species is attacked by another member of the same species, this has been witnessed in some species in the form of infanticide, for example. There's also interspecific trauma where a member of one species is attacked by a member of a different species. And as I mentioned earlier, we see this not infrequently in the form of bottlenose dolphins attacking smaller species.
Such as the harbour porpoise, and you can see that's sadly what's happened in the two photos on the left at the bottom of the screen. You can see the deep rake marks on the left photo, and those are spaced about 1 centimetre apart, which is consistent with a rake from a bottlenose dolphin. The wound in the middle photo is thought to have been caused by a blunt trauma purely from the sheer force of such a large animal ramming into it and literally splitting the soft tissues.
You can imagine that these animals can suffer some pretty severe internal injuries too as a result of the attack, and it's no surprise that they end up stranded. Animals can also become entangled in marine litter, most often discarded or lost fishing gear, otherwise known as ghost gear, and this can cut into soft tissues over time. And as with the entangled seals, they can suffer from the impact of carrying around sometimes large volumes of net which impairs their ability to swim and hunt.
Boat and propeller strikes aren't as common, but are seen on occasion and can cause some serious injuries. All these different types of threats and trauma can lead to various severities of wounds, fin fractures and dislocations, spinal and muscle damage, and internal organ damage and haemorrhaging too. Malnutrition and starvation can be seen in animals with a chronic disease or due to old age, or in the case of maternally dependent calves, separation from their mother.
These two photos sadly show emaciated common dolphin calves which have become separated from mum. The bottom photo was a particularly interesting case because this calf also had rake marks on it, but these were more consistent with intraspecific aggression and suggesting it had actually been attacked by another common dolphin, and this is actually, you know, quite an unusual observation for this species. Gas bubble disease in marine mammals is akin to decompression sickness or the bends in human divers.
It's something that you might have heard of, but for those who don't know, decompression sickness happens when nitrogen dissolves into the blood at high pressures, such as during a deep dive, and then on an ascent, which is too rapid, it comes out of solution as the pressure decreases and will actually form bubbles. And these can form in any part of the body and will actually cause a whole host of different and potentially serious problems. An acute form is seen in deep diving whale species and is hypothesised to happen when their regular dive pattern is interrupted.
So that is sort of shallow compensatory dives that are taken after long deep dives, and that allows for nitrogen off gassing. Military sonar has been implicated as a factor leading to this interruption and then mass strandings of beaked whales occurring as a result of this. And the last topic I wanted to mention was net entanglement.
It's most common that animals that are by-caught or entangled at sea will unfortunately drown and strand dead rather than alive, but it's not impossible for them to live strand with ghost gear still attached to them. These animals could be in a poor condition and unwell if that material has prevented them from feeding, for example. Sometimes you'll see animals that have signs of a previous entanglement like the common dolphin here, and with its very clean linear cut encircling its head, and it can be quite difficult to determine if that entanglement contributed to its eventual stranding.
So moving on to looking at what the role is of the veterinary team at Cetacean strandings, I emphasise here that this is the veterinary team, not just the vet. So I'm also including veterinary nurses who will of course also have invaluable skills to bring to the scene, and I speak from previous experience when I say that it can be really helpful and comforting to have a professional colleague to work alongside and bounce ideas off. Vets will also find having a nurse present extremely useful when they're attempting to attach a satellite tag, for example, as ideally you want your assistant to understand, prepare and be comfortable working in an aseptic environment.
So the veterinary team are on scene to perform a patient assessment, decide on whether a refloat should be attempted or not. If so, and if a tagging kit is on scene, attach a satellite tag then and supervise the refloat. Otherwise, if the animal isn't suitable for refloat, then they're gonna be responsible for overseeing the animal's euthanasia.
BGMLR will always work hard to try and ensure that a vet attends the animal, as we believe this is extremely important, but sometimes this just isn't physically possible due to the location, and then our veterinary consultants will attempt a basic assessment over the phone with the lead medic and any photos. But we aren't ever going to significantly delay a refloat just to wait for a vet, especially when there are strong indicators that the animal is in good health and will hopefully survive. There's a photo here of one of these satellite tags.
We have 8 tagging kits located strategically all around the country. And they're designed to help us with post-release monitoring of refloated cetaceans. It's not always possible to get a tagging kit on scene quickly enough to actually fit one, and we never want to again delay a refloat longer than we have to.
But when we can fit one, we should, as they are important, an important part of ensuring that animals' welfare is safeguarded. For example, we're going to want to know about it if a refloated dolphin actually ends up stranding again somewhere else nearby and needed to be reassessed and helped again. All the tagging kits come with a detailed tagging protocol which you can follow on scene with myself as your contact call if you do have any problems.
But I'm afraid we don't have time to discuss the tags in, in detail here. As well as those main aims around animal care, the veterinary team also have other duties at strandings. They are, of course, responsible for any controlled drugs that they've brought onto the scene for euthanasia purposes and also for the safety of the volunteers who may be working around them in regard to those drugs.
It's best to keep them in a secure container on your person at all times, and if you can remember to bring a mini sharp's bin and somewhere to dispose of your used syringes and any other sort of contaminated materials, then that would be brilliant. You also need to ensure that you're communicating effectively with other team members, which may include a wide variety of people such as BGMLR medics or BGMLR local area coordinators and emergency services as well, such as the RNLI, the Coast Guard, and police. So you can see in this photo, the, minke whale, which sadly stranded recently in the Thames, and our team, being assisted by the RNLI at the time.
Identify who the lead medic is on scene and make sure that you're keeping them well informed of your findings and your thoughts as you go along. They may have a lot more experience at strandings than yourself, and although they might not be veterinary trained, they can still offer a whole wealth of knowledge based on their previous experiences, which is definitely worth keeping in mind. Finally, it's fantastic if you are able to help us fill in our paperwork regarding the stranding.
It's not a very glamorous job, but it is critical that we note down as much information as we can about these strandings so we can learn from them and contribute to research. A veterinary professional's input in terms of clinical exam findings and information regarding the euthanasia is really invaluable and greatly appreciated. These forms are called mark forms, that's Marine Animal Rescue Coalition forms, and someone on scene should have a copy for you to contribute to.
Excellent teamwork is absolutely essential for ensuring that animals get the very best of care at strandings. We promote strong communication, mutual respect and a supportive atmosphere at all times. Vets and veterinary nurses clearly bring a very specialised skill set and a huge amount of knowledge with them to these events, but they also need to recognise that they are part of a wider team of people, all with different skills and experiences to bring to the table.
And although medics are aware that a vet's decision regarding euthanasia, for example, should always be respected, we try to ensure that everyone is on a level playing field and treats one another with respect, no matter what their background is. And I know I've said this a few times over these talks, but once again, BGML our head office and our veterinary consultant team will be available over the phone to assist you when needed, so please don't hesitate to get in touch if you have any questions or concerns. And now to look at the final topic for this talk, which is health and safety at cetacean strandings.
So there is potentially quite a list of risks to be aware of when attending attending a stranding. First, there is the risk of exposure to a zoonotic disease, most notably is brucella SEI, which I mentioned earlier and has been shown on very rare occasions to infect humans that have been exposed to cetaceans. Then there is the risk of injury, which is much higher when working with larger species.
Generally just take care when handling the mouth, as their teeth can be quite sharp and avoid stepping over or walking too close to the tail, which even in small species could easily knock you off your feet or potentially cause you some serious damage if it is a larger species. You can see in this photo, two firemen trying to restrain the tail of a whale by leaning on it. This is definitely not advised and if the animal wanted to move them, it would have absolutely no problem doing that.
You also need to be aware of any environmental hazards you might be exposed to. This might be as simple as working on slippery rocks or in thick mud, or it might mean planning escape routes if the tide is starting to come in, or just dressing appropriately to avoid hypothermia if the weather is cold or if you're going to go in the water, etc. Lastly, be aware of what controlled drugs you have on your person and have a plan if yourself or someone else is accidentally exposed to them.
It can be helpful to take the data sheets along with you just in case to refer to. And here are some of the ways to alleviate these risks. PPE comprising of gloves and an FFP3 mask are essential for working around cetaceans.
If you don't have an FFP3 mask, it's likely someone else on scene will have one for you to use. Avoid the tail, as discussed, and if you're entering the water, you must wear a life jacket. Again, we should be able to provide this and you should also have adequate thermal protection.
Ideally, this would be a dry suit, but a wetsuit is OK for short durations of time. Watch out for signs of hypothermia in yourself and others, and sometimes you'll see we do have to swap people in and out during long refloats to keep everyone comfortable. Move carefully around the environment, particularly if it's slippery.
These events can be quite stimulating and exciting, but it's definitely not a good time to try and run and end up injuring yourself, and effectively add another casualty to the scene. As with seals, we generally advise you to not work in close contact with cetaceans if you are pregnant or immunocompromised. And that concludes this first talk on cetacean strandings.
I bring you back now to the dolphin which has stranded on your local beach and wanted to pose a few questions for you to think about before starting the next talk. Now I know this isn't the best photo, but I've done that a little bit on purpose because often we'll be sent photos that aren't ideal from members of the public to try and assess animals from. But regardless, what species do you think this is, how long can adults of that species grow to, and can you list reasons why this dolphin may have stranded?
Thank you very much for listening and I'll speak to you in the next talk.