Brown catshark
Encyclopedia
Brown catsharks, Apristurus brunneus, (originally, Catulus brunneus) are commonly found in the Pacific ocean, ranging from the northern Pacific waters off the coast of British Columbia
and down to the Baja California
peninsula
in Mexico
. It is believed that they may live as far south as Ecuador
and Peru
. Brown Catsharks are deep water sharks that live on the outer continental shelf
and the upper slope. They have been known to live in depths ranging from 30 to 650 m and live on the bottom, usually in muddy or sandy areas.
, however they live most of the year near the edge of the continental shelf.
Communication specific to brown catsharks is unknown. However, as with most other sharks, including other members of the family Scyliorhinidae, it is believed that they have a well-developed sense of smell, and that they are electroreceptive, which allows them to detect electricity emitted by other animals, and may also allow them to detect magnetic fields, which aides in navigation
.
.
It is believed that brown catsharks are preyed on by larger sharks and fish species, however these species are currently unknown.
. Egg cases are usually about 5 cm long and 2.5 cm wide. The egg cases are transparent and have long tendrils that are probably used to attach them to hard structures. The incubation period is possibly a year. In Canadian waters females carry egg cases from February to August, however, the carrying time for warmer waters is unknown.
, the U.S. Federal List, or the CITES list. They are not known to be a vulnerable
or threatened species. They are, however, listed on the IUCN list as needing to be reclassified.
The only known negative impact that brown catsharks have on humans is the frequent bycatch
of deepwater fishing trawlers, which while not economically significant can cause damage to nets as well as time lost in removing the bycatch from the viable catch.
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
and down to the Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
peninsula
Peninsula
A peninsula is a piece of land that is bordered by water on three sides but connected to mainland. In many Germanic and Celtic languages and also in Baltic, Slavic and Hungarian, peninsulas are called "half-islands"....
in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It is believed that they may live as far south as Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
and Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
. Brown Catsharks are deep water sharks that live on the outer continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
and the upper slope. They have been known to live in depths ranging from 30 to 650 m and live on the bottom, usually in muddy or sandy areas.
Physical description
Brown catsharks have long, slender bodies with broad, bell-shaped snouts. They are dark brown with light colored markings on the posterior margins of their fins. Their bodies are soft and flabby, with a weak skin that can easily be harmed. Brown catsharks have two dorsal fins that are the same size and do not have spines. The first dorsal fin originates to the front of the pelvic fin and the second dorsal fin is located in front of the anal fins insertion. They typically reach a maximum size of 68 cm in total length, however they average between 30 and 60 cm.Behavior
Very little is known about the behavior of brown catsharks, however they are believed to be solitary, nocturnal creatures. It is believed that they are migratoryFish migration
Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres...
, however they live most of the year near the edge of the continental shelf.
Communication specific to brown catsharks is unknown. However, as with most other sharks, including other members of the family Scyliorhinidae, it is believed that they have a well-developed sense of smell, and that they are electroreceptive, which allows them to detect electricity emitted by other animals, and may also allow them to detect magnetic fields, which aides in navigation
Navigation
Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
.
Food habits and predation
Brown catsharks feed on many bottom-dwelling species, including small true shrimps, euphausiids, squids, and small fishes. It is unknown whether brown catsharks are important predators within their ecosystemEcosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
.
It is believed that brown catsharks are preyed on by larger sharks and fish species, however these species are currently unknown.
Reproduction
Reproduction in brown catsharks is oviparous with a single egg at a time per oviductOviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
. Egg cases are usually about 5 cm long and 2.5 cm wide. The egg cases are transparent and have long tendrils that are probably used to attach them to hard structures. The incubation period is possibly a year. In Canadian waters females carry egg cases from February to August, however, the carrying time for warmer waters is unknown.
Conservation status and economic impact
Brown catsharks are not listed as endangered on the IUCN Red ListIUCN Red List
The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...
, the U.S. Federal List, or the CITES list. They are not known to be a vulnerable
Vulnerable species
On 30 January 2010, the IUCN Red List of Threatened Species identified 9694 Vulnerable species, subspecies and varieties, stocks and sub-populations.-References:...
or threatened species. They are, however, listed on the IUCN list as needing to be reclassified.
The only known negative impact that brown catsharks have on humans is the frequent bycatch
Bycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
of deepwater fishing trawlers, which while not economically significant can cause damage to nets as well as time lost in removing the bycatch from the viable catch.