By: Matthew Lombardo
The Sperm Whale:
A summary of the Recovery Plan for the Sperm Whales and their current endangered status
The Sperm whale is a unique species of marine mammal. It gets its name from the large organ in its blunt snout that is filled with spermaceti oil. This organ acts as a very strong sonar system that allows the sperm whale to use echolocation to catch its prey. Sperm whales are mainly dark grey in color, with white areas on their belly and flanks. They have a disproportionately large head - about one quarter to one third of their total body length - that contains the largest brain of any animal on Earth. In their lower jaw, they have 20-26 pairs of teeth. They have a very similar ear anatomy to the Bottlenose dolphin, which allows them to be receptive to ultrasonic sounds. Sperm whales produce several types of clicking sounds that are used for social communication, locating their food during dives, and for mating. The adult male sperm whales can grow to over 18 meters and 57 metric tons, while the females can are 12.5 meters and 24 metric tons. The males can live to at least 60 years of age, and the females have been known to reach 80 years.
Sperm whales can be found dispersed
around the world in the Atlantic, Pacific, and Indian Oceans, although adult
male and female whales have remarkably different migratory patterns throughout
their lives. Male sperm whales tend to migrate toward colder waters in the
summer feeding season and then return to warmer waters to breed. Both females
and young males are found throughout the tropical and temperate seas. The sperm
whale’s main food source is large squid, but they also eat sharks, skates, and
fishes. The availability of food sources - impacted by fishery operations,
human-caused environmental deterioration, or natural processes - may strongly
affect the size and distribution of the sperm whale population.
The sperm whale was originally listed
under the Endangered Species Conservation Act of 1969, and remained on the list
of Endangered Species after the passage of the Endangered Species Act (ESA) in
1973. Although the original listing did not state a specific explanation, it
was widely understood that the reason for listing is that most populations of
sperm whales had been depleted by commercial whaling. Whaling of the sperm
whale ended in 1988 when a moratorium was put into place by the International
Whaling Commission (IWC). While it is assumed that the worldwide population of
sperm whales has increased since the moratorium was put into place, there is
insufficient data on the population structure and abundance of the inhabited
ocean basins to accurately determine population trends. Despite
the fact that the main threat to sperm whales was addressed by the IWC
moratorium, many other threats remain. Among the current threats to sperm
whales are collisions with ships, reduced availability of food due to climate
change, illegal whaling, pollution, contamination of the environment, and the
effects of increasing anthropogenic ocean noise.
The
primary purpose of the Recovery Plan is to identify and take actions to
minimize or eliminate the effects of human activities that are detrimental to
the recovery of sperm whale populations. The immediate goal is to get sperm
whales downlisted from the Endangered Species list to the Threatened Species
list; however, the ultimate goal is to promote their recovery to the point that
they aren’t on either of the lists. An important part of the plan is to
determine the population structure of the species in order to get an accurate
assessment of population size and trends in abundance. The recovery plan also
includes actions to maintain international regulation of whaling, protect their
habitat, reduce human-caused injury and mortality, and determine any
detrimental effects of anthropogenic noise in the oceans. The estimated cost of
this recovery plan is $174 million and the anticipated date of recovery is
2035.
The Sperm whale is a unique species of marine mammal. It gets its name from the large organ in its blunt snout that is filled with spermaceti oil. This organ acts as a very strong sonar system that allows the sperm whale to use echolocation to catch its prey. Sperm whales are mainly dark grey in color, with white areas on their belly and flanks. They have a disproportionately large head - about one quarter to one third of their total body length - that contains the largest brain of any animal on Earth. In their lower jaw, they have 20-26 pairs of teeth. They have a very similar ear anatomy to the Bottlenose dolphin, which allows them to be receptive to ultrasonic sounds. Sperm whales produce several types of clicking sounds that are used for social communication, locating their food during dives, and for mating. The adult male sperm whales can grow to over 18 meters and 57 metric tons, while the females can are 12.5 meters and 24 metric tons. The males can live to at least 60 years of age, and the females have been known to reach 80 years.
Sperm whales can be found dispersed
around the world in the Atlantic, Pacific, and Indian Oceans, although adult
male and female whales have remarkably different migratory patterns throughout
their lives. Male sperm whales tend to migrate toward colder waters in the
summer feeding season and then return to warmer waters to breed. Both females
and young males are found throughout the tropical and temperate seas. The sperm
whale’s main food source is large squid, but they also eat sharks, skates, and
fishes. The availability of food sources - impacted by fishery operations,
human-caused environmental deterioration, or natural processes - may strongly
affect the size and distribution of the sperm whale population.
The sperm whale was originally listed
under the Endangered Species Conservation Act of 1969, and remained on the list
of Endangered Species after the passage of the Endangered Species Act (ESA) in
1973. Although the original listing did not state a specific explanation, it
was widely understood that the reason for listing is that most populations of
sperm whales had been depleted by commercial whaling. Whaling of the sperm
whale ended in 1988 when a moratorium was put into place by the International
Whaling Commission (IWC). While it is assumed that the worldwide population of
sperm whales has increased since the moratorium was put into place, there is
insufficient data on the population structure and abundance of the inhabited
ocean basins to accurately determine population trends. Despite
the fact that the main threat to sperm whales was addressed by the IWC
moratorium, many other threats remain. Among the current threats to sperm
whales are collisions with ships, reduced availability of food due to climate
change, illegal whaling, pollution, contamination of the environment, and the
effects of increasing anthropogenic ocean noise.
The
primary purpose of the Recovery Plan is to identify and take actions to
minimize or eliminate the effects of human activities that are detrimental to
the recovery of sperm whale populations. The immediate goal is to get sperm
whales downlisted from the Endangered Species list to the Threatened Species
list; however, the ultimate goal is to promote their recovery to the point that
they aren’t on either of the lists. An important part of the plan is to
determine the population structure of the species in order to get an accurate
assessment of population size and trends in abundance. The recovery plan also
includes actions to maintain international regulation of whaling, protect their
habitat, reduce human-caused injury and mortality, and determine any
detrimental effects of anthropogenic noise in the oceans. The estimated cost of
this recovery plan is $174 million and the anticipated date of recovery is
2035.
Works Cited:
- Picture 1 http://upload.wikimedia.org/wikipedia/commons/b/b1/Mother_and_baby_sperm_whale.jpg
- Picture 2
http://us.whales.org/sites/default/files/styles/content_full/public/species/maps/map_sperm_w.png?itok=0-M73dgs
- Picture 3
http://theseamonster.net/wp-content/uploads/saving-sperm-whale-from-net-Alberto-RomeoMarine-Photobank.jpeg
- Picture 4
http://images.nationalgeographic.com/wpf/media-live/photos/000/113/cache/sperm-whale-eating-jumbo-squid-mouth_11399_600x450.jpg
- Picture 5
http://3.bp.blogspot.com/-rGcI5bHVdk4/TnXufLDIh9I/AAAAAAAACN8/Zeb6PjWE33A/s1600/Whale+Hunting.jpg
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