According to statistics from the Fish & Wildlife Foundation of Florida , about 2,000 cetaceans wash up on beaches around the world each year . In most cases, the consequences are lethal for the animal, and although they are rare enough not to pose a serious risk to the species, they can be red flags indicating that something is not right ; that something is causing these strandings that could be dangerous for the populations.
Among the causes that can lead a cetacean to be trapped on the beach, many are natural, but there are also others of human origin; actions or events for which humanity is responsible, which could be preventable.
Natural causes
Among the reasons why a dolphin or a whale ends up stranded is, first of all, the environment. At the bottom of the ocean there are valleys and mountains, plains and cliffs, just like on land. But in addition, there are currents that in the aquatic environment are much stronger than those that occur in the atmosphere.
A cetacean, in adverse weather conditions, can easily be overwhelmed by the environment and end up washed up on the beach. If you go into shallow water, and the tide goes out, it is easy to become disoriented and end up running aground. In some regions, the tide can recede horizontally for several kilometers, and it is not uncommon for animals that are there at that time to be exposed. Natural disasters, such as tsunamis or volcanic eruptions, can accentuate these events.
However, the most common natural cause of stranding is for health reasons. It is not uncommon for a sick or injured cetacean to come ashore and end up stranded. With certain health problems, the whales run out of strength to return to the high seas and are victims of the currents. On the other hand, very old cetaceans can become senile, become disoriented and wander into shallow water by mistake.
On other occasions, simply the relationship of cetaceans with other animals is what leads them to stranding. Be it dolphins escaping from a predator, or killer whales trying to hunt down prey in shallow waters. When this happens, the killer whales have a certain ability to return to the sea taking advantage of the waves, but they do not always succeed.
When the fault is ours
However, human activities are included among the most relevant causes of stranding of cetaceans. Our behaviors that can lead these animals to the agony of being trapped on dry land.
The overcrowding of people on the beaches or motorized boats, particularly those with sonar, generate a great deal of noise pollution that can disorient perfectly healthy cetaceans and cause them to enter shallow waters from which they can no longer get out. Sometimes, since sounds are much louder underwater than in air, they can cause damage to your hearing. A cetacean with this problem will not be able to submerge successfully, it will be difficult for it to feed and it will weaken, letting itself be carried away by the currents. Other reasons for similar weakening are the crashes of boats against these animals and the injuries that their propellers can cause.
In addition, for centuries humans have used the oceans as garbage containers . Abandoned fishing nets and lost fishing lines can become entangled in the body of cetaceans, trapping, immobilizing or incapacitating them. And we already know what happens if the animal cannot feed properly.
Speaking of fishing, the overexploitation of this resource on the high seas pushes cetaceans, which need to eat, to get closer to the coasts, where not only all kinds of garbage abound, but it is also easier for them to end up stranding.
Chemical contaminants or microplastics have been found with some frequency in the bodies of stranded animals. However, in this regard, it is difficult to establish a cause and effect relationship, and correlation does not always imply causation. It could be that the greater presence of pollutants in the body is not the cause of the stranding, but that both events share a common cause, which is proximity to the coast.
What if I find a stranded cetacean?
It is not easy, and on many occasions, despite good intentions, people act irresponsibly. First of all, you have to check if the animal is still alive and call the emergency services —whether it is or not. If the animal has died, it is best not to approach it and let the authorities take care of it; the scientific information that can be obtained from such an animal is incredibly extensive, and the evidence could be contaminated. On the other hand, you never know what diseases it could transmit.
If the animal is alive, the scenario is very different. The action of the emergency services must be facilitated as much as possible . It is essential to avoid crowding. While the emergency services arrive, we can do a few things for the animal, as long as we can access it. Two or three people can carefully cover the animal’s skin with damp towels to prevent sunstroke, without covering the spiracle , that is, the breathing hole. The areas that should be cooled the most are the fins, where the animal perspires, but always with the precaution of not harming it. Those towels may heat up faster, and need to be changed more often. If possible, installing some umbrellas nearby so that it is in the shade is not a bad idea.
In general, touch them as little as possible , but above all, be very careful with the fins; They are very sensitive areas . If you find remnants of fishing nets or fishing lines, and you have a cutting tool at hand, you can try to remove them, taking extreme precautions. In case of doubt, it is better to let the professionals take care of it.
In any case, in no case return the animal to the water , even when it is a small cetacean that can be carried. A sick and weakened animal will beach again even if you return it, and handling it can hurt it, especially if its fins are grabbed.
There will be times when the authorities, after an evaluation, return it to the ocean; this is done using special stretchers if the animal is small, or waiting for the tide to rise and helping it return to the water on its own if it is very large. But sometimes, before being returned to the natural environment, they may need a veterinary check-up, or even a period of quarantine and recovery in a specialized center. At other times, you will not be able to return and your only chance will be to enter a center. If he is lucky and succeeds, he will have a new life there and will provide us with a lot of scientific knowledge that we can use for his benefit and that of his peers.
REFERENCES:
Fernández, A., Arbelo, M., et al. 2013. No mass strandings since sonar ban. Nature, 497(7449), 317-317. DOI: 10.1038/497317d
Grammatica, K. 2019, agosto 14. Why Do Whales Beach Themselves? Fish and Wildlife Foundation of Florida. https://wildlifeflorida.org/
Jiménez Cáceres, A. 2019. Living blue: in our hands. Books.com.
Stonehouse, B., Camm, M., et al. 1998. Whales: a visual introduction to whales, dolphins, and porpoises. Facts On File.
