About sea lion sightings on Mexican Pacific beaches

During the winter months there are several sightings of sea lions on the beaches of the Mexican Pacific, so here is an interview with an expert on pinnipeds. Dr. Fernando Elorriaga Verplancken.

What are the differences between a seal and a sea lion?

They belong to different families (Phocidae and Otariidae). Sea lions have ears, seals do not. Sea lions move on land with their front and hind flippers; while seals cannot do this and rather "crawl", like a caterpillar moves.

What is the common habitat of sea lions and seals? Do they only live in cold areas like the North Pole?

Seals (e.g. harp, leopard, and crabeater seals) are more common in cold areas such as the poles. While sea lions and fur seals are more common in temperate and tropical habitats. In warmer sites, where there is occasionally sufficient food, sea lions such as the California, Galapagos, and South American fur seals inhabit.

In Mexico, what is the common habitat of sea lions and seals, and in what areas or regions do they rest, breed and feed?

In Mexico, the California sea lion, Guadalupe fur seal, northern elephant seal, and common seal inhabit. Their settlements are found in the northwestern part of the country, especially on islands off the Baja California Peninsula and in the Gulf of California. On these islands, they breed, molt and rest. They feed around the islands; except for adult elephant seals that migrate to the northern Pacific Ocean.

Do sea lions live in packs or are they solitary?

Sea lions form large aggregations, especially on the beaches of the islands where they live, due to the reduced space. The packs on the islands are larger during the summer because they gather to reproduce. In the sea, it is also common to observe sea lions feeding in groups, surrounding large schools of fish such as sardines.

The individuals that can be seen in the open sea, are they lost, are they old or young, what is their purpose of travel?

In most cases, they are immature animals (juveniles or sub-adults) that are not as experienced as adults. Their main purpose is to search for prey. When there is anomalous warming or cooling of the sea (e.g. "El Niño" and "La Niña"), they may disperse more and there may be unusual records, either because food is scarce or because conditions related to their food are more extended than usual.

If a sea lion is observed on a beach in southern Mexico, is this an alarming situation?

Not necessarily. Sometimes they are just passing through, resting after a long journey at sea. They may leave the place by themselves after a few days. The best thing to do is to report the case to the authorities and give them their space, do not disturb them, and be careful with pets. There may be a health problem involved, so reporting and monitoring by the authorities are important.

What characteristics or conditions would a wolf seen on a beach have to show to be a health concern?

a) That it presents clear injuries, such as those caused by fishing nets, boat propellers, blows, and gunshots, among others. b) That it does not react or does not move even though it is still alive. c) That its body is observed as "very skinny", being very evident in its ribs and spine. It is also alarming that a sea lion or seal seen on a beach is stressed by the surrounding people or their pets.

How is a sea lion stranding defined?

If the animal is dead or alive but does NOT react or CANNOT move, being unable to return to the sea on its own. The reasons for a stranding can be illness, injury or stroke, lack of food, or some other condition that afflicts the normal condition of the individual.

In a stranding situation, what can civil society do and what should they NOT do?

It is best to keep your distance and not attempt to touch or feed. Live animals can hurt a person because they are stressed. They can also transmit disease. Dead animals pose a risk to human health. It is advisable to record the scene and take photographs or video if possible. And notify the authorities (911).

Who are the experts or authorities that should be notified to attend to a situation that compromises the health of a sea lion?

The Procuraduría Federal de Protección al Ambiente (PROFEPA) in conjunction with the Red Local de Atención a Varamientos (Local Stranding Attention Network), formed by specialists in marine mammals. In the case of a protected natural area, the National Commission of Natural Protected Areas (CONANP) should also be notified.

We thank Dr. Fernando Elorriaga for giving us some of his time and sharing his knowledge about this great marine creature. Source: Buena Mar No.9, University of Colima.