Cormorant culling is the intentional killing of cormorants by humans for the purposes of wildlife management. It has been practiced for centuries, with supporters of culling generally arising from the angling community. Culling techniques may involve the killing of birds, the destruction of eggs, or both. Historically, culls have occurred to protect the interests of recreational and commercial fishermen who perceive the animals to be competing with them for their intended catch or for the prey of their intended catch. Since the 1960s, the growing aquaculture industry has undertaken cormorant culls to protect its farmed fish and crustacean stocks. Opponents of cormorant culling include conservation groups such as the National Audubon Society, Cormorant Defenders International [1] and Sea Shepherd. [2]
The target species are primarily the double-crested cormorant in North America and the great cormorant in Europe, Japan, and Australia. The little black cormorant has also been targeted in Australia. In Africa, the reed cormorant is targeted and shot.
Before Europeans became a major presence, double-crested cormorants lived throughout much of their current North American range, usually in populations far greater than 21st century observations. After birdwatching near Natchez, Mississippi in December 1820, John James Audubon reported:
“We saw to day probably Millions of those . . . Cormorants, flying Southwest—they flew in Single Lines for several Hours extremely high.” [3]
No comparable numbers of the birds can be seen today.
After a protracted period of cormorant population reduction due to expanding human settlement, breeding habitat loss, and persecution in the forms of shooting and egging, a turning point for the species was reached in 1972. The National Audubon Society listed the double-crested cormorant as a species of special concern. The state of Wisconsin declared cormorants endangered and began building nesting structures to help them return. The use of DDT, a chemical agent which was proven to thin cormorant eggs and had impacted recruitment since its introduction following World War II, was banned. Congress also signed a revised Migratory Bird Treaty Act granting cormorants federal protection. Since that time, the species has been recovering. [3]
Catfish and baitfish aquaculture have grown rapidly since the 1960s, particularly in the south-eastern United States. Open aquaculture ponds provide winter or year-round homes and food for cormorants on the species' long-established migration route. This has also led to conflict and prompted culling at aquaculture facilities. Cormorants’ effect on the aquaculture industry is significant, with a dense flock capable of consuming a harvest. Cormorants are estimated to cost the catfish industry in Mississippi alone between $10 million and $25 million annually. [3]
The double-crested cormorant is the only species appreciably found inland in the United States. [3]
Shooting is the most commonly employed and immediately effective method of cormorant culling. Sharpshooters are sometimes hired to undertake the work (Shiga prefecture, Japan) and in some jurisdictions, hunters are issued permits to allow them to kill these otherwise protected birds (South Carolina, United States). Birds can be shot on the water, on the wing, or at their breeding sites.
The smothering of eggs with food-grade corn oil is another method employed by authorized persons. Once applied, the eggs' porous surface, which allows the transport of oxygen, becomes clogged with oil. The parent birds continue to incubate the oiled eggs, which ultimately fail to hatch.
Cormorant culling has occurred in many countries including Australia, the United Kingdom, Germany, Estonia, Japan, the United States and Canada.
The culling of cormorants occurred in Australia from the 1900s [4] [5] to the 1960s [6] for the purposes of reducing competition with recreational and commercial fisheries. In some cases, bounties were offered as incentives to encourage people to hunt the birds. [5] Primary target species included the little black cormorant and great cormorant.
In New South Wales, a bounty was in place for a number of years prior to 1919. It was discontinued as inland cormorant populations continued to be replenished via migration and it was proven to be ineffective in preventing fish losses. During the bounty period approximately 44,000 cormorants were killed. [7]
Since the development of the aquaculture industry, cormorants have been responsible for some stock losses including at commercial prawn farms. In Bowen, Queensland, the use of non-lethal methods to deter the animals from settling on farm ponds and feeding on farmed prawns has been adopted in favor of culling. [8]
In April 1905, the South Australian government inaugurated a bounty of 1d per head of cormorant or freshwater turtle. Prior to May 1908, 25,537 cormorant heads were paid for, and 89,333 turtles. Most of the cormorants came from Kangaroo Island and Franklin Harbor rookeries and the turtles were caught in the Murray River and its lakes. [9]
In the year 1909–1910, 3183 cormorants were destroyed in South Australia, with bounties paid for their heads. During the same period, 18,706 turtles were also culled as both animals were considered 'enemies' of fish. The total combined bounty paid was £91 4/. [10]
Opponents of the cull argued that cormorants were responsible for keeping toadfish and leatherjacket numbers in check on Kangaroo Island, and that these fish, feeding on the larvae of other fish, likely had a greater impact on reducing quantities of preferred target species than the cormorants' own fishing practices. They argued that the animals should be protected, not hunted. [11]
In Tasmania in 1954 a bounty on the heads of cormorants was proposed at 5/ per head. The proposal was supported by anglers, who expressed their concern at the animal's impact on trout populations inland. [12] The bounty was raised from 3/6 to 5/- to encourage people to hunt the birds. Tasmania's Northern Fisheries Association responded by planning a special 'black cormorant day' of hunting. [13]
In New Brunswick, cormorants are classified as a varmints. As such, holders of a varmint hunting license can kill them in unlimited numbers between early March and late September each year. [14]
On Middle Island in Lake Erie, the double-crested cormorant population is managed by the Canadian government. The first three breeding pairs were seen on the island in 1987, and over the following twenty years their population increased to over 5,000 pairs. [1] In 1998, a group of fishing guides undertook an unauthorized cull, shooting cormorants on Little Galloo Island in Lake Ontario. Estimates of the scale of the cull range from 800 [1] to 2000 birds. Eventually the perpetrators were brought to justice. [3] Nonetheless, as of 2014, increasing pressure on the island and lake's other species via competition, habitat alteration and predation has created the case for culling as a management strategy. [1]
In 2013, the Japanese population of great cormorants, Phalacrocorax carbo , was estimated to be over 100,000 birds. Conflict between increasing great cormorant populations and the ayu (or ayu sweetfish Plecoglossus altivelis ) has led the Japanese government to implement cormorant culling. The ayu is one of the most popular species for commercial and recreational fisheries in Japan.
In Shiga prefecture, great cormorants have been responsible for impacts to forests (through alteration of habitat and guano deposition) and fisheries (through predation). At the Lake Biwa rookeries, between 10,000 and 25,000 cormorants were shot annually between the years 2004 and 2012 (with the exception of 2008, during which no birds were shot). Since 2009, sharpshooters have been employed by the government to undertake the culling, replacing hunters. [15]
In 2010, 2000 cormorants were culled in the United Kingdom under special licences according to the Royal Society for the Protection of Birds. The animals have been protected from arbitrary killing in the UK since 1981. [16] A cull for environmental protection purposes is underway at Haweswater, United Kingdom where cormorants are killed for the protection of schelly, an endangered whitefish species.
In thirteen states of the United States, aquaculture producers may shoot cormorants which feed on their stock in private ponds. They may also call upon government wildlife managers to shoot birds found roosting nearby. Local managers in twenty-four states are allowed to suffocate cormorant eggs with oil, destroy their nests, or kill cormorants that threaten public resources, such as wild fish, plants, and other birds’ nesting areas. [3]
Individuals and states are permitted to kill a total of 160,000 cormorants each year. An average of about 40,000 cormorants are reported killed each year—perhaps amounting to 2 percent of North America's population. The kill statistics do not include the tens of thousands of eggs oiled annually. [3]
In 2000, an unauthorized cull was undertaken on Little Charity Island in Saginaw Bay, Michigan that killed more than 500 cormorants. Despite lacking the required permits to kill the protected species, the perpetrators were not brought to justice. [3]
In the span of one month, commencing in February 2014, hunters culled 11,653 double-crested cormorants during a licensed action in South Carolina. 1,225 permits were issued to hunters to kill cormorants during this period. One hunter alone reported killing 278 birds. Similar hunts occurred in Indiana, Michigan, Minnesota, New York, Ohio, Vermont, and Wisconsin in 2013, resulting in a combined total cull of 21,312 cormorants. The culling was unsuccessfully opposed by the Audubon Society. [17]
A cull of 16,000 double-crested cormorants along the Columbia River in Oregon has been proposed to commence in 2015 and is intended to reduce pressure on salmon stocks. [2]
The long-term ecological effects of cormorant culling are uncertain and disputed. Cormorant numbers are effectively reduced during culls, but the targeted species remain in recovery after centuries of arbitrary killing and habitat loss. A paucity of dietary studies also means that the impact cormorants have on commercially important species (with the exception of pond-based aquaculture) are difficult to estimate. One unintended consequence of cormorant culling is that managers who enter nesting grounds to cull or oil eggs may cause more harm to other bird species in the process than the nesting cormorants do themselves. [3]
The primary justification for the culling of cormorants is to reduce pressure on wild or farmed fish populations. It has been suggested that humans have caused the damage to fisheries and aquatic ecosystems through overfishing, introduction of exotic species and pollution. It has been further suggested that money spent trying to manage cormorants could be better used in reducing coastal pollution, securing conservation land and marine preserves, and assisting aquaculture producers and fishermen to develop new bird conservation practices. [3]
Fish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environments. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia.
Phalacrocoracidae is a family of approximately 40 species of aquatic birds commonly known as cormorants and shags. Several different classifications of the family have been proposed, but in 2021 the International Ornithologists' Union (IOU) adopted a consensus taxonomy of seven genera. The great cormorant and the common shag are the only two species of the family commonly encountered in Britain and Ireland and "cormorant" and "shag" appellations have been later assigned to different species in the family somewhat haphazardly.
The double-crested cormorant is a member of the cormorant family of water birds. It is found near rivers and lakes and in coastal areas and is widely distributed across North America, from the Aleutian Islands in Alaska down to Florida and Mexico. Measuring 70–90 cm (28–35 in) in length, it is entirely black except for a bare patch of orange-yellow facial skin and some extra plumage that it exhibits in the breeding season when it grows a double crest in which black feathers are mingled with white. Five subspecies are recognized. It mainly eats fish and hunts by swimming and diving. Its feathers, like all cormorants, are not waterproof, and it must dry them out after spending time in the water. Once threatened by the use of DDT, the numbers of this bird have increased markedly in recent years.
The great cormorant, known as the black shag or kawau in New Zealand, formerly also known as the great black cormorant across the Northern Hemisphere, the black cormorant in Australia, and the large cormorant in India, is a widespread member of the cormorant family of seabirds. The genus name is Latinised Ancient Greek, from φαλακρός and κόραξ, and carbo is Latin for "charcoal".
The yellow perch, commonly referred to as perch, striped perch or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Samuel Latham Mitchill from New York. It is closely related, and morphologically similar to the European perch ; and is sometimes considered a subspecies of its European counterpart.
The ayu sweetfish, ayu or sweetfish, is a species of fish. It is the only species in the genus Plecoglossus and family Plecoglossidae. It is a relative of the smelts and other fish in the order Osmeriformes.
The Laysan albatross is a large seabird that ranges across the North Pacific. The Northwestern Hawaiian Islands are home to 99.7% of the population. This small gull-like albatross is the second-most common seabird in the Hawaiian Islands, with an estimated population of 1.18 million birds, and is currently expanding its range to new islands. The Laysan albatross was first described as Diomedea immutabilis by Lionel Walter Rothschild, in 1893, on the basis of a specimen from Laysan Island.
The loggerhead sea turtle is a species of oceanic turtle distributed throughout the world. It is a marine reptile, belonging to the family Cheloniidae. The average loggerhead measures around 90 cm (35 in) in carapace length when fully grown. The adult loggerhead sea turtle weighs approximately 135 kg (298 lb), with the largest specimens weighing in at more than 450 kg (1,000 lb). The skin ranges from yellow to brown in color, and the shell is typically reddish brown. No external differences in sex are seen until the turtle becomes an adult, the most obvious difference being the adult males have thicker tails and shorter plastrons than the females.
The green sea turtle, also known as the green turtle, black (sea) turtle or Pacific green turtle, is a species of large sea turtle of the family Cheloniidae. It is the only species in the genus Chelonia. Its range extends throughout tropical and subtropical seas around the world, with two distinct populations in the Atlantic and Pacific Oceans, but it is also found in the Indian Ocean. The common name refers to the usually green fat found beneath its carapace, not to the color of its carapace, which is olive to black.
Wolf hunting is the practice of hunting wolves. Wolves are mainly hunted for sport, for their skins, to protect livestock and, in some rare cases, to protect humans. Wolves have been actively hunted since 8,000 to 10,000 years ago, when they first began to pose a threat to livestock of Neolithic human communities. Historically, the hunting of wolves was a huge capital- and manpower-intensive operation. The threat wolves posed to both livestock and people was considered significant enough to warrant the conscription of whole villages under threat of punishment, despite the disruption of economic activities and reduced taxes. The hunting of gray wolves, while originally actively endorsed in many countries, has become a controversial issue across the globe. Most people see it as cruel, unnecessary and based on misconceptions, while proponents argue that it is vital for the conservation of game herds and as pest control.
Culling is the process of segregating organisms from a group according to desired or undesired characteristics. In animal breeding, it is removing or segregating animals from a breeding stock based on a specific trait. This is done to exaggerate desirable characteristics, or to remove undesirable characteristics by altering the genetic makeup of the population. For livestock and wildlife, culling often refers to killing removed animals based on their characteristics, such as their sex or species membership, or as a means of preventing infectious disease transmission.
The environmental impact of fishing includes issues such as the availability of fish, overfishing, fisheries, and fisheries management; as well as the impact of industrial fishing on other elements of the environment, such as bycatch. These issues are part of marine conservation, and are addressed in fisheries science programs. According to a 2019 FAO report, global production of fish, crustaceans, molluscs and other aquatic animals has continued to grow and reached 172.6 million tonnes in 2017, with an increase of 4.1 percent compared with 2016. There is a growing gap between the supply of fish and demand, due in part to world population growth.
The Sea Turtle Restoration Project (STRP), founded in 1989, is a project of Turtle Island Restoration Network (TIRN), a United States 501(c)(3) nonprofit environmental organization with a goal of protecting endangered sea turtles from human-caused threats at nesting beaches and in the ocean.
Overpopulation or overabundance is a phenomenon in which a species' population becomes larger than the carrying capacity of its environment. This may be caused by increased birth rates, lowered mortality rates, reduced predation or large scale migration, leading to an overabundant species and other animals in the ecosystem competing for food, space, and resources. The animals in an overpopulated area may then be forced to migrate to areas not typically inhabited, or die off without access to necessary resources.
Huckleberry Island is an island in Long Island Sound and part of New Rochelle, New York. It lies approximately three-fourths mile (1.2 km) east of Davids Island. The 10 acres (4.0 ha) island consists primarily of deciduous forest with virtually no shrubs or herbaceous growth under the canopy. The rocky shoreline supports a marine rocky intertidal community comprising one of the most southerly occurrences of this community type on the North Atlantic Coastline.
The aquaculture of salmonids is the farming and harvesting of salmonid fish under controlled conditions for both commercial and recreational purposes. Salmonids, along with carp and tilapia, are the three most important fish groups in aquaculture. The most commonly commercially farmed salmonid is the Atlantic salmon.
Castle Rock National Wildlife Refuge is 0.5 miles (0.80 km) offshore from Crescent City in northern California. This coastal rock covers approximately 14 acres (57,000 m2), and rises steeply 335 feet (102 m) above sea level. The refuge provides an important sanctuary for the Aleutian cackling goose and nesting seabirds.
Gravel Island National Wildlife Refuge is a National Wildlife Refuge located off the Door Peninsula in Wisconsin. Founded in 1913, the refuge consists of two Lake Michigan islands that act as nesting grounds for native bird species. It is inhabited by large colonies of shore birds and waterfowl in addition to hosting a pair of great black-backed gulls, one of farthest westward breeding sites of the species.
The fauna of Louisiana is characterized by the region's low swamplands, bayous, creeks, woodlands, coastal marshlands and beaches, and barrier islands covering an estimated 20,000 square miles, corresponding to 40 percent of Louisiana's total land area. Southern Louisiana contains up to fifty percent of the wetlands found in the Continental United States, and are made up of countless bayous and creeks.
Seal culling in South Australia was strongly advocated for in 2015 in response to increasing interactions of Arctophocaforsteri, the indigenous long-nosed fur seal, with the state's fishing industry. In the 19th century, both fur seals and Australian sea lions were hunted for their hides. During the 20th century, seals were sometimes culled on the assumption that they were competing with fishermen. As of 2018 seal culling is illegal, but remains a topic of public debate. All pinnipeds in South Australia remain fully protected under the National Parks and Wildlife Act 1972 as listed Marine Mammals. As of 2016, there were an estimated 100,000 long-nosed fur seals in South Australian waters.