Unraveling Whale Entanglements
Disentanglement Teams Rescue Marine Mammals From Ocean Debris
Disentanglement teams work in partnership with agencies like the Coast Guard to free marine mammals like whales that become entangled in debris and old fishing gear
Care of marine mammals is entrusted in the United States with the National Marine Fisheries Service (NMFS) which is part of the National Oceanic and Atmospheric Agency (NOAA). Marine debris poses an imminent danger to marine mammals like whales, seals, and dolphins. Entanglement in things like fishing gear lead to the establishment of a Disentanglement Network linking first response personnel for the first time across the United States and Canada. It is estimated that 50% of whale fatalities are caused by ship strikes or entanglements. In Alaska, 65% of Humpback whales bear scars from entanglement encounters.
Disentanglement Teams - First responders are members of regional disentanglement teams that operate under permit from the Federal government to handle protected and endangered marine mammal. The Northern Right whale would be one example. Teams are charged with assessing successful opportunities for freely marine mammals from entanglements and documenting the effect of marine debris on the animals. Responders may attach satellite tracking buoys to whales with entanglement problems to follow their movements and plan for gear removal in a more favorable location or conditions. Coast Guard assets are often used to quickly assist rescue teams in incidents that are often far from shore.
Technique - Modifying a practice of old whalers, the standard method of disentanglement entails attaching large floats or buoys to gear entangling the whale called kegging. Attaching floats to the whale increases the buoyancy of the debris entangling the animal and slows it down. Once a whale is tired and not moving freely, the ensnaring gear can safely be cut free. Buoys used in the rescue are designed to be easily released in the event of an unsuccessful attempt to remove the debris. Freeing marine mammals from entanglements requires specialized training and equipment. The public should avoid attempting a rescue on their own initiative that can place them and the animal at risk.
Rescuers use small rigid hulled inflatable boats to approach animals in the water. These craft are very maneuverable and less threatening to the animal. Disentanglement team members do not enter the water to assist in rescues. The danger posed by rescuer entanglement in the same offending gear is too great and just a slight movement of a whale can easily injure a diver. Special cutting grapples first designed by rescuers in New England are used to remove gear after the whale has slowed down.
Marine Mammal Entanglements and Strandings - These incidents can make one of these presentations:
- The animal is moving with gear or lines attached to it
- The animal is entangled in gear or line and is not moving
- The animal is diseased or ill
- The animal is dead and cause of death needs to be determined
The rescue of individual whales is deemed important by marine mammal experts. Populations are diminishing and there is the importance of individuals in the whale social structure. An example is Killer whales that live in matrilinear groups and pass cultural knowledge down from grandmother to granddaughter whales. The knowledge and contribution of one whale can affect the livelihood of the greater group. The Endangered Species Act requires the Federal Government to pursue a variety of methods to preserve at risk animal populations, disentanglement is one of many options employed by natural resource managers.
