About the Gulf of Maine

Right Whales — on the Brink

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Current Threats to Right Whale Recovery

The same characteristics which made the right whales easy to hunt — their slow speed and surface habits — also make them vulnerable to other human threats.

Vessel Collisions

Right whales are found resting, socializing and feeding near the surface in coastal areas of high vessel density. Designated navigation routes overlap right whale habitat and collisions with vessels are a known cause of right whale mortality. It is estimated that collisions with vessels have accounted for the mortality of at least 13 right whales since 1976, one third of all documented right whale deaths. Scientists believe this number represents only a portion of the total number of whales struck by vessels, because many whales that die in these collisions drift out to sea and are never found.

Entanglements in Fishing Gear

When whales and other marine mammals become entangled in fishing gear, they may not be able to feed or may be held underwater by the nets, unable to breathe. There have been 16 recorded encounters between right whales and fishing gear in the North Atlantic between 1975 and 1989. Three whales are known to have died from entanglements. Photographs show that 57% of the catalogued whales have scars and injuries resulting from rope and net cuts.

Ecosystem Changes

General degradation of coastal marine habitats is also an important factor affecting the whales’ recovery. Untreated sewage and wastewater, silt, gas, oil and other pollutants in the ocean can affect the whales’ health directly, and may also have an impact on the populations of crustaceans they feed on. Toxins in the crustaceans can build up in the tissues of whales in a process called bioaccumulation. Ship traffic and other operations may also disturb the whales and interfere with their communication.

Inbreeding

Genetic studies show that the current population of right whales descend from a small number of unrelated females. This small breeding pool may affect how often and how successfully the whales reproduce. Inbreeding may also produce more still births and a lowered survival rate in the offspring. Scientists have indeed noted that the interval between calves appears to be increasing.