Men of Excellence
banner

cluster maritime français

 

Scientist Area

This page is not a biology course, it aims two goals. The first is to introduce the species we meet during our missions. The second is to make a brief inventory of the dangerous sources for these animals, including noise pollution.

 

What is a Marine Mammal?

Mammals frequenting water. Vertebrate animals characterized by the presence of udders. As mammals, they are breathing air and they can't live without it. They need to come regularly breathing at the surface. They carry their young in their belly (viviparous) and are nursing them.

Marine mammals are divided into several groups:


Marine Mammals totally depending to water

1 - Cetaceans (carnivorous mammals) which consist of:

1.1 - Mysticetes (baleen whales have no teeth), which include whales, rorquals, grey whales and humpback whales. Mysticetes feed on plankton and other tiny prey.

1.2 - Odontocetes (have teeth), which include: the sperm whales, killer whales, the dolphins, beaked whales, the beluga and narwhal.

2 - Sirena (phytophagous mammals) which include:
- The manatees,
- The dugongs.


Animals partially related to water

1 -Pinnipeds. These carnivorous mammals go out of the water to rest or to bring their young into the world. They collect three families:

1.1 Phocidea:
- The true seals (including the elephant seals and the leopard seal),

1.2 Otaridae:
- Seals (including sea lions).

1.3 Les Odobenidae:
- Walrus,
- Sea Otter and Marine Otter.

 

Other species

1 - Turtles.


Threats

1 - Fishermen

Marine mammals have been massively driven up, some species extermined as the Steller’s Sea Cow . Since the 1950s, the hunting of cetaceans has been reduced, while hunting seals, walruses and sea lions didn’t slow until the end of 1970s. For fishermen, these animals, almost all carnivores with the exception of Sirenia, competitors, and as such, are badly perceived. The accidental capture of cetaceans by fishing is a threat to the conservation of the species.


2 - Sonar

Experts believe that the sonar average frequency may cause a whales deafness and encourage them to run aground on the shore. Military sonars with low frequency are also accused.

3 - Explosions

Seismic data acquisition is the technique used by the producers of oil in the context of the prospecting. This method used at sea entails risks for marine mammals because explosions are likely to temporarily or permanently damage hearing and balance organs.

4 - Pile driving

The pile-driving produces sound waves that disperse in the water over a radius of several kilometres. The piling with hydraulic hammers produced a strong noise which endanger marine mammals and fish, located around the site.

 

5 - Ship strikes

Every year, dozens of marine mammals are killed in collisions with ships.