Hello and welcome to the 4th and final webinar in this series on non-captive marine mammal medicine in the UK. In this talk, we'll be discussing stranded cetacean, health assessment and decision making. So at the end of the last talk, I left you to think about these questions regarding the stranded dolphin that you've been called to.
So you can just about see a goldeny yellow coloured patch on the side of this dolphin, which makes this extremely likely to be a common dolphin, one of the cetacean species which strands most commonly in the UK. As I explained in the last talk, common dolphins can grow to be about 2.5 metres long.
As to why this dolphin may have stranded, you should now know that there are a whole host of reasons why a dolphin might strand, and that dolphins may strand in a healthy condition due to navigational error, disturbance, and due to close social bonds, as well as strand in an unhealthy condition due to illness, injury, or malnutrition, or possibly a combination of these factors. Extra credit to those people who remembered that common dolphins are a pelagic species and hence have a higher likelihood of stranding just due to navigational error, as they are less adept at navigating shallow and tidal waters. So I'll give you a few more details about the stranding, and then we'll go through basic cetacean health assessment and decision making before coming back to wrap it up.
So you've arrived on scene. Medics are carrying out first aid, and the medic in charge relays the following information to you. The dolphin was discovered stranded about 1 hour ago on the high tide line, and medics have been on scene performing first aid for 15 minutes.
The tide is going to be low in about 2 hours. The respiratory rate is 7 breaths per minute. There are some wounds on the pectoral fins and tail flukes which are bleeding, and the tail is trembling.
The animal is measured to be about 2 metres long. So start having a think about this scenario and just keep it in mind while we go through the following slides. I first wanted to explain basic cetacean first aid to you.
Our medics are trained in these techniques during our course, and you'll often arrive on scene with medics already carrying out these measures. The main aim of the first aid is to reduce the animal's stress and prevent severe strandings related pathology from developing, and we'll discuss this in more detail shortly. So the general advice is to support the cetacean in an upright position, remove any sharp stones they might be lying on, and if possible, move them onto a soft, supportive surface.
This might just be some seaweed stacked up to form a sort of mattress, or some medics might be carrying an airbed, for example, for this purpose. If they are lying directly on the ground, dig trenches under their pectoral fins to allow them to rest in a more natural position either side of the body. Make sure that they're kept wet.
Cover them in wet bed sheets if possible, and pour water over them regularly, making sure to not let any areas of skin dry out. Don't cover their head or blow hole, and the blowholeles should be shielded from any water running down off their body with a cupped hand again, though not disrupting air flow in or out of the blowhole. Look at the weather and decide if they need any additional protection.
If it's very sunny, they might need some shade creating, or if it's very windy, then use windbreaks to protect them from drying out, for example. Keep the atmosphere calm and quiet to reduce stress. This is really important.
So here are some photos showing first aid in progress on a number of different cetaceans. You can see teams of people working to keep them moist and kits such as airbeds being utilised to take some of the pressure off their bodies and just to keep them more comfortable. In the bottom left photo, a medic is shielding the blowhole from water running down off of the wet sheets.
The type of kit present on scene is going to vary hugely from perhaps just a bucket and a bed sheet all the way up to our specialist refloatation pontoons. We do just have to work with what we've got at the time and make use of the environment too, like, you know, for example, using the seaweed as a as a mattress, as I said before. Next, I wanted to discuss strandings related pathology, that is pathology that develops as a direct result of the stranding and hence also impacts healthy individuals as much as it might unhealthy ones.
Firstly, there may be a trauma as a result of the physical stranding process. Most often this is only going to result in superficial wounds, but it does have the potential to be more serious. For example, if stranding onto a rocky shoreline in rough seas when fractures and other major trauma will be possible.
The two photos show just some superficial damage from stranding. Then after the animal has stranded, there is the potential for quite rapid deterioration due to four main factors pressure, temperature, desiccation, and stress. Clearly, cetaceans have not been designed to live on land.
Their bodies are designed to be constantly supported by the water. This means when on land, their bodies suffer as they slowly start to effectively crush themselves under their own weight, with this impacting the larger species much more quickly. There will be muscle damage, pooling of blood where circulation is compromised, and this circulatory collapse also leads to ischemia of the kidneys and other organs.
Also, also rather sorry, renal damage occurs as a result of myoglobin release from the damaged muscles too. So altogether it's a pretty potent cocktail of issues that will arise from this. As well as the effects of pressure, these animals suffer quickly from hypothermia out of the water, and again this is more severe in larger species.
Although hypothermia is much more often the concern at cetacean strandings, hypothermia is also possible, for example, in emaciated or very young animals. They are also at risk of drying out. Their skin is extremely delicate and will quickly start to wrinkle, peel, and crack out of the water.
There's quite a risk of significant amounts of skin being lost, and this will lead to dehydration and the possibility of secondary bacterial infections. And finally, stress itself can have a big impact on these animals and their chances of recovery, hence why we do everything we can to try and lessen it. Not all strandings related pathology is easy to detect, but it's worth keeping in the back of your mind as a reason why an animal may not have a successful refloat, for example, myocardial degeneration.
This table gives you a rough guide as to the length of time different sizes of cetacean can survive when stranded. You can see while a porpoise or a dolphin may be able to survive more than 12 hours with good support, large whales may only survive a few hours, and for sperm and beaked whales this may only be a couple of hours. You'll notice that the toothed whales are impacted to a greater degree than baleen whales.
This is because they are a much more heavily muscled, sort of group of animals and more likely to suffer from the effects of pressure and overheating. So you can see from this information that it's important to try and determine how long a cetacean has been stranded as part of the process of making an assessment and to help inform decision making. A member of the public may have seen it strand or can at least tell you when they first observed it stranded, or you might be able to use tidal information to assist you.
For example, if you can see it's stranded on the high tide line. So as part of your assessment of the animal, it's important to first do some information gathering, which will help you with your decision making later on. So firstly, if not already done, make sure that you're confident which species it is and record an accurate length if possible.
A medic on scene should hopefully have their handbook which has a species ID section, or you could send photos off to head office for identification. Then, as I said on the previous slide, try to determine the length of time the animal's been stranded by talking to the member of the public who called a BDMR in the first place if they're still there, or look for environmental clues such as the position in relation to the tide. If someone did witness the actual stranding, it's really worth asking what its behaviour was like pre-stranding.
So uncoordinated movements and listing in the water, for example, might indicate that the animal was already unwell before stranding. This photo was taken a few minutes before the dolphin at the bottom right of the image decided to turn and swim quite purposefully into the shallows and strand itself near where I'm standing on the left. We had been monitoring it and another dolphin which had become trapped up this river at low tide, and their behaviour seemed normal at first, but it became increasingly agitated and stressed as the water became more shallow.
So it was really interesting to witness that firsthand and also a comfort to me later that I knew that they could both swim normally and with some strength. And that obviously gave me a bit more confidence that a refloat, once the tide was high again, was the right decision. It's also really important to determine if the animal could still be maternally dependent.
Signs of an animal being a very young calf include the presence of an umbilical remnant, of course, as in other species, but you can also see foetal folds, which you can see as pale sort of vertical lines on this common dolphin calf in the left photo, which form when the animal is actually curled up in the womb. Lingal papillae, which are the sort of nodular structures protruding around the edge of the tongue in the middle photo, help calves to latch on for suckling milk. And then you have the neonatal hairs, such as the ones in the picture on the right here which form on the calve's rostrum and disappear after around 2 to 3 weeks.
If there are no obvious signs of an animal being a very young calf, you should measure their body length and check the information provided in the BDMLR handbook or call head office to ensure that they are likely to be weaned and not still dependent. Sadly, it's often the case that lone stranded maternally dependent calves do need to be euthanized and should never be refloated unless you are absolutely certain that there are members of the same species in the nearby area. Without their mother, they're not going to survive and are most likely just going to starve, so it is in their best interests to put them to sleep.
So now moving on to the actual physical assessment of the animal. One of the most important factors to assess is body condition, as this is often a good indicator of health and suitability for a refloat. However, as always, there are going to be exceptions to this, and animals suffering from an acute onset condition may present in good condition, but not be suitable for a refloat.
We have 3 pictures of cetaceans here at varying levels of body condition from good on the left to poor on the right. So we advise positioning yourself down at the animal's level and looking down their body, allowing a good view of the musculature ventral to the dorsal fin. An animal in good condition should be convex in shape and well rounded.
A concave shape indicates poor condition, and the animal on the right is actually pretty emaciated. Of course, then you'll have a range of animals in between these extremes, and that's where it can get tricky. Sending photos like these to head office will allow us to assist you with the assessment.
Do always remember that because these animals are on land, their body mass is being pushed upwards artificially by the pressure against the floor, so condition may actually appear better than it really is. Animals in poor condition unfortunately should be euthanized and not refloated. Next, you should make sure to carry out a thorough respiratory assessment as pneumonias are really common.
Respiratory rates vary between different species, and they typically get slower in larger animals. You can see from the table here that dolphins and porpoises tend to have a normal rate of between 2 and 5 breaths per minute, and deep diving whales like a sperm whale may only take a breath every 20 minutes. The respiratory rate should be monitored regularly, and medics are trained to do this, as it's a great way of determining if first aid measures are making a difference to the animal's stress levels.
Normal breaths are quite explosive and fast due to the nature of how sed cetaceans ventilate, but a gap between expiration and inspiration, a bad smell or a discharge from the blowhole, and certainly coughing and sneezing are all indicators of an underlying respiratory condition. Listen carefully to the lungs, bearing in mind that they will sound normally noisier than domestic species, and listen for areas of consolidation, crackles and wheezes, etc. To assess the cardiovascular system, check the mucous membrane colour, which should be pink or pale pink.
The capillary refill time should be between 1 and 2 seconds, and it's normal for them to have a marked sinus arrhythmia when listening to the heart. Signs of shock are common in stranded cetaceans. Hopefully first aid measures will have prevented the skin from drying out, but make sure you look over their whole body to assess the extent and severity of any skin damage that is present.
And also dehydration can sometimes be detected by palpating the animal's flank and feeling a loss of tone or sponginess when normally they should feel very firm and springy almost. Now, some animals are very passive and non-vocal on the beach and therefore assessing their level of consciousness can actually be quite difficult. Checking reflexes and tone can help with this, and I've listed some of the things you can check here, including the palpibril and pupillary light reflex, the menace response, and the blowhole reflex, and that's where the blowhole tightens on touching its edge.
You can also assess jaw tone carefully, and if you gently pull on a pectoral fin, you should feel the animal resisting you when conscious. So this information can just help give you an idea of how conscious a quiet animal is. Others might be, you know, moving their tail and vocalising, etc.
Which obviously makes this then less important. Ensure you also check for any obvious signs of internal bleeding, such as blood coming from the blow hole, mouth, anus, or genital slip. While checking for this, you can also see what gender the animal is.
In cetaceans, this is pretty easy because females have two mammary slits which lie laterally on either side of the genital slit. Males obviously don't have these, and instead you'll just see one genital slit cranially and the anus cordially. Obviously, if you see any injuries, then you're going to want to have a good look at them and decide if they're severe enough to prevent a refloat from occurring.
Stranding's damage is very common and usually superficial as we saw earlier, and usually won't prevent a refloat from going ahead. However, more serious injuries such as fractures or deep wounds from boat strikes, for example, may mean an animal needs to be euthanized. I've put the image of the porpoise with the bottlenose dolphin rakes here again, as although it had much more severe injuries, you can see how deep these wounds alone were going right down into the muscle.
And of course this gives the clue that internal injuries are likely as well. The images on the right are of the fin whale from 2020 again. You can see strandings related damage around its eye, and sadly the wounds on its tail are mostly from it beating its tail up and down against the rocks once it is stranded.
We also want to be aware of anything indicating the animal has an infection of some sort, and I know that sounds a very vague thing to ask, but in particular I mean assessing wounds for signs of infection and respiratory signs such as a blowhole discharge. I also wanted to mention parasites briefly. We regularly see an ectop parasite called whale lice, which is photographed here at the top, and they will latch on to healing wounds on cetaceans, and a heavy burden can indicate that an animal is debilitated because they tend to be able to hold on more easily to slower moving animals.
So that can be quite a nice little clue that the cetacean might already be unwell. Cetaceans often carry worm burdens in the lungs and stomach, though it's rare to attend a strand stranding where these are being expelled from the body. If so, the animal is, you know, fairly likely to be, you know, pretty unwell, and in a poor overall condition.
Now it used to be that we'd advise using rectal probes to take the temperature of stranded cetaceans, but actually they give very inaccurate readings and need inserting over 30 centimetres in most animals to reach the location that it needs to be in. So they end up being both inaccurate and stressful, which clearly isn't ideal. So nowadays we actually prefer to just palpate the tail flukes and pectoral fins to get a rough manual indication of their body temperature.
And of course we know most of the time hyperthermia is more of a concern than being too cold. This is the last slide on assessment, and it's basically just to say that blood sampling is possible and can be really useful for helping to determine an animal's prognosis by looking at PCV and renal values and muscle enzymes in particular. However, very often, it just isn't practical to collect a sample, transport it to a lab and get a result back in time to actually be of use.
And as I said before, we really don't want to delay a reflow attempt if we're fairly confident that the animal is well enough. We're aware of devices like the ISA, which can be taken into the field for blood sampling, but you know, obviously the, the costs of such items are very high. But just so you're aware, blood samples are usually taken from the central tail veins, which travel down either side of each tail fluke, and you can see, that demonstrated on the bottom left image here.
So now we move on to looking at how cetaceans can be stabilised at strandings. We've already looked at first aid measures and how they're designed to reduce the effects of pressure, heat, desiccation, and stress. To mention stress again, we like to try and ensure any members of the public and potentially crowds that gather are kept well informed but a suitable distance away from the animal.
We also try to only have the minimum number of people required in close contact with the animal at any one time. And we keep our voices low and calm and avoid walking around right in front of their head at ground level. And certainly I can't really emphasise enough just how critical it is to minimise stress for them.
Just like the skin, the eyes are also at risk from being out of the water. If possible, when you have some, use an ocular lubricant to help prevent this happening, or you can just flush them regularly with some saline, and just obviously remember to do that gently. Superficial corneal ulcerations may occur due to stranding, and you can consider applying an antibiotic drop on scene to try and help prevent infection.
Also just to note that it's quite normal to see quite a bit of clear viscous discharge coming from the eyes of stranded cetaceans, as in this top photo here. Superficial and non-significant wounds can be cleaned and flushed. Topical preparations tend to just wash off really quickly, so it might not be worth doing.
Suturing wounds is definitely not advised. Wound dehiscence is very likely, and of course you'll have no control over the wound post-release. We used to recommend giving stranded cetaceans oral fluids via an orogastric tube to counteract the shock many of them are experiencing, but nowadays we advise using intravenous fluids instead wherever possible.
This is per the International Fund for Animal Welfare's marine mammal rescue and Research Protocol for live stranded cetaceans. Fluids can be administered via the central tail vein as seen earlier, and generally a proportion of a shock dose is given and then the animal reassessed and more fluids given as needed. If you're at a stranding and would like further information on this technique, then please call head office and ask to speak to a veterinary consultant for the correct volumes to give, etc.
Some vets recommend giving cetaceans a long-acting antibiotic before release, even if they appear well, just in case the stress of the stranding and any associated injuries, etc etc. Precludes an infection starting up. Generally we advise not to give sedatives or opioids as they can be very potent in citations and their duration of action extended to a point where a refloat might not even be possible.
We also advise against steroids and antomenttics. NSA can be of value, but you should use them with caution in animals that aren't fully rehydrated, which, of course, often is the case in these animals. And these drugs should typically be given IM into the area highlighted here on the diagram beneath the dorsal fin.
Going subcu is extremely difficult and most often you'll just end up injecting into the blubber layer where drug absorption is poor and abscess formation possible. So after completing a full assessment and doing what you can to stabilise the animal, keeping in mind there might not always be the resources there to give IV fluids or take blood samples, for example, it's time to start considering the decision that you're facing, and this can sometimes be incredibly difficult. The reason it's so hard is because you're looking at two extremes in the UK.
We can either hope for a successful refloat back into the sea or the cetacean is going to be euthanized. Rehabilitation of cetaceans is absolutely not possible in the UK at present. We have no existing facilities that can support such a costly and difficult operation as trying to rehab a cetacean, and we also have to look at the success rates of other rehab centres around the world, which are actually very low indeed, and consider if it's worth the cost and challenges for such a small number of animals.
To attempt a refloat of a cetacean, we want it to be in good or fair body condition with no significant injuries or illness and no other issues of concern, for example, you know, being a maternally dependent calf, and just overall to have what we think is a good prognosis for long term survival in the wild. In animals with poor body condition, significant injuries or illness, or if they've re-stranded multiple times or had a poor response to refloatation, then sadly the best option for the sake of the animal's welfare is to put them to sleep. This can be really hard, heartbreaking decisions to make, and that's why we try to make decisions a, a sort of team effort as much as possible to try and take the load off of any one person.
You know, certainly as I've said before, just don't ever be afraid to ask for help from head office. Photographed are two common dolphins I attended. The one in the top photo was in good condition and just seemed to be lost at the tidal river.
So, here we are loading it into a small boat to be released back out in deeper water, which actually went really well. And in the bottom photo, this dolphin unfortunately required euthanasia due to its very poor condition, but that was, you know, absolutely the right thing to do for the animal. OK, so here we are again, back with the dolphin that is stranded nearby to your practise and the details which the lead medic on scene had passed on to you.
So it was discovered on the on the high tide line about an hour ago. Low tide is due in 2 hours. The respiratory rate was 7 breaths per minute.
It's 2 metres long and has some bleeding wounds. Now here are the results of your assessment. So you've determined this is a common dolphin which has been probably stranded for approximately 4 hours, as it was found on the high tide mark and low tide is now about 2 hours away.
It's 2 metres long, so is an adult and definitely not maternally dependent. On examination, you've seen that it's a male in good body condition. Its lungs sound clear and the mucous membranes are pink, and its respiratory rate is now 5 breaths per minute, and the tail is trembling less.
The breathing rate has now returned to normal, which is usually between 2 and 5 breaths per minute, indicating that the first aid is helping, and also indicated by the reduction in tail trembling, which I've seen, commonly in stress cetaceans. So, I hope you'd agree that this animal is suitable for a trial reflotation. We still can't guarantee that this is gonna be successful, but at the moment these signs are good.
And once the decision has been made to trial a refloat and hopefully a satellite tag has been attached where possible, the BGMLR medics on scene will be able to step in. They're trained to safely load dolphins onto tarpaulins and transport them into the water. They're gonna be carried in up to about waist deep water and gently supported in the water while keeping the blowhole above the surface.
They will gently rock the animal from side to side, which helps them to get back their equilibrium with the water and restore their circulation. Cetaceans must never ever be dragged or moved by their tail, dorsal fin or pectoral fins. It can cause serious stress and damage to the animal.
The dolphin may need supporting like this in the water for a long time, depending on the animal, and can eventually be released when they are attempting to swim and holding themselves in the water. Once released, they should be monitored really carefully for as long as possible for abnormal signs such as tremors, body flexion, or listening to one side, not lifting the head to breathe, or just moving in an uncoordinated or weak fashion. Some animals may be caught and assessed again in the water, and then some of these signs may disappear with some more time, but multiple re-strandings is a real concern and indicates that there is an underlying serious problem.
Now with your dolphin that you saw earlier, we'll keep it as a happy ending and assume that he went off fine back into the sea and he had no problems at all and lived a long, happy life. However, it is a sad reality that a lot of the time these animals strand with significant health concerns and will require euthanasia. And of course the veterinary team needs to know how to go about doing that safely.
Again, this is still focusing very much on small cetacean species rather than thinking about whales, for example. So actually it can be a very simple and smooth procedure. You're just injecting pentobarbital into the central tail veins, that I showed you earlier.
And it's at a dose rate around equivalent to that of which you'd give a dog. Though I find often you don't really need quite as much as that. Make sure the tail is adequately restrained before injecting as a tail, to the face can do some real damage, even in a small dolphin.
I tend to use 1 to 2 inch 18 to 21 gauge needles and have found inserting a butterfly needle on an extension line helpful in case the animal starts flinching or moving partway through the injection. The central tail veins can be accessed dorsally or ventrally, but I prefer the dorsal approach, as in this photo. And sometimes you can actually see the vein itself.
Other times it's a bit of a fishing trip, but keep in mind that the vessel is really quite superficial. You can also try to access the caudal peduncle on the underside of the tail stock just off the midline, or vessels centrally in the dorsal fin. Or you can go, IP as a last resort.
Most of the time euthanasia is very smooth, but you can see bad reactions as you do in other species. And I would advise some sedation IM beforehand if you have it, for example, some midazolam. To estimate the animal's weight, refer to the BGMLR handbook or call the hotline, and you should be able to get a rough estimate of weight based on body length and species.
So here are some common dolphin weights, for example. So your 2 metre long common, probably weighed around 125 kg. You do also have shooting as an option for smaller cetaceans.
Sometimes it is carried out if a vet can't attend or if the vet didn't have any drugs with them, or sometimes if a body can't be recovered after chemical euthanasia will choose to shoot instead to save contaminating the environment. Clearly there are big issues here around health and safety and public perception too. We'll generally inform the police if this is happening and they may choose to attend the scene as well and help with moving crowds away.
However, this is fairly rare overall, and most of the time small cetaceans will be euthanized chemically. The shot is usually taken in front of the animal, aiming at a 45 degree angle through the blowhole towards a line midway between the pectoral fins and at a distance of no more than 1 metre. Head office are normally going to be quite actively involved if firearms are needed at a stranding.
And so that brings us to the end of this webinar series. So over 4 talks we've explored how to assess and stabilise rescued seal pups and learned about the problems that they commonly present with. We've also learned about why cetaceans strand, what role the veterinary team plays at strandings, and how we can perform a basic assessment and what goes into the critical decision making for these animals.
I really, really hope that you've enjoyed learning about some of the marine mammal work that goes on in the UK, particularly with British divers Marine Life Rescue, and hopefully learn some useful and practical information that you can take away with you and maybe put into practise one day when you're faced with a real life seal pup or dolphin. If you're interested, please do go over to our website and read about our marine mammal medic courses. We're always looking for more veterinary support across the country and we'd love to have you join the charity as a qualified medic.
The course covers some of the elements that we've been through in these webinars, but goes into much more detail in regard to rescue skills. And of course we have our famous practical sessions with our life-size seal pups, dolphins and whales. We're also developing further learning and training resources for our veterinary members, so watch this space as there are some exciting things to hopefully come.
Many thanks for listening.