Rock sole
Encyclopedia
The rock sole, Lepidopsetta bilineata, is a flatfish
of the family Pleuronectidae
. It is a demersal fish that lives on sand and gravel bottoms at depths of up to 575 metres (1,886.5 ft), though it is most commonly found between 0 and 183 m (0 and 600.4 ft). Its native habitat is the temperate waters of the northern Pacific
, from Baja California
to Alaska
, the Aleutian Islands and southeastern parts of the Bering Sea
. It grows up to 60 centimetres (23.6 in) in length and can weigh up to 1.8 kilograms (4 lb), and has a maximum recorded lifespan of 22 years.
and the rock sole, Lepidopsetta bilineata, were considered to be a single species under the genus
Lepidopsetta
, but work by Orr & Matarese published in 2000 reorganised the genus into three separate taxa
.
As a result of this reclassification and renaming, the rock sole may be referred to as the "southern" rock sole, in order to avoid confusion with the Northern rock sole L. polyxystrata.
.
organisms such as molluscs, crustacean
s, brittle star
s, marine worm
s and other fish.
s, Alaska pollock
, yellowfin sole
, Pacific halibut
and Pacific cod
.
in winter through to early spring. Eggs are demersal and stick to the surface on which they are laid; hatching takes from 6 to 25 days.
fisheries
in the Bering Sea and Gulf of Alaska
. Although it was overfished
in the 1960s stocks have recovered, and the biomass
of rock sole in the Bering Sea and Aleutian Islands fishery is now estimated to be very high, at twice the level required to support maximum sustainable yield
. In 2008 the estimated rock sole biomass in the Gulf of Alaska fishery was some 161,617 tons, compared to catches ranging from 1,468 tons in 2004 to 4,260 tons in 2007. Alaska accounts for the majority of the worldwide harvest of this fish, catching over 52,000 tons of rock sole in 2008.
Rock sole fishing off the coast of the United States is managed by the Pacific Fishery Management Council and the North Pacific Fishery Management Council, two of eight U.S. Regional Fishery Management Councils
.
Flatfish
The flatfish are an order of ray-finned fish, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migrating through and around the head during development...
of the family Pleuronectidae
Pleuronectidae
Righteye flounders are a family, Pleuronectidae, of flounders. They are called "righteye flounders" because most species lie on the sea bottom on their left side, with both eyes on the right side. The Paralichthyidae are the opposite, with their eyes on the left side.Their dorsal and anal fins are...
. It is a demersal fish that lives on sand and gravel bottoms at depths of up to 575 metres (1,886.5 ft), though it is most commonly found between 0 and 183 m (0 and 600.4 ft). Its native habitat is the temperate waters of the northern Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, from 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...
to Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
, the Aleutian Islands and southeastern parts of the Bering Sea
Bering Sea
The Bering Sea is a marginal sea of the Pacific Ocean. It comprises a deep water basin, which then rises through a narrow slope into the shallower water above the continental shelves....
. It grows up to 60 centimetres (23.6 in) in length and can weigh up to 1.8 kilograms (4 lb), and has a maximum recorded lifespan of 22 years.
Taxonomy and Nomenclature
Prior to 2000 the Northern rock soleNorthern rock sole
The Northern rock sole, Lepidopsetta polyxystra, is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on sand, mud and gravel bottoms at depths of up to , though it is most commonly found between...
and the rock sole, Lepidopsetta bilineata, were considered to be a single species under the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Lepidopsetta
Lepidopsetta
Lepidopsetta is a genus of fish in the Pleuronectidae family.Since it was erected by William Orville Ayres in 1862 it has taken in Platessa bilineata, Platichthys umbrosus, Isopsetta isolepsis, Lepidopsetta mochigarei, Lepidopsetta bilineata, Lepidopsetta bilineata bilineata, Lepidopsetta bilineata...
, but work by Orr & Matarese published in 2000 reorganised the genus into three separate taxa
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
.
As a result of this reclassification and renaming, the rock sole may be referred to as the "southern" rock sole, in order to avoid confusion with the Northern rock sole L. polyxystrata.
Description
The rock sole is a right-eyed flounder. Its upper surface is grey to olive to dark brown or black, lighter or darker mottling, and is sometimes marked with yellow or red spots; the underside is light. Its dorsal and anal fins have dark blotches or bars, and near the tail fins may be yellowish. The caudal fin is convex - rounded or broadly v-shaped. It has a small mouth with fleshy lips, and teeth are more strongly developed on the underside.Role in ecosystem
The rock sole occupies a moderately high trophic level in the food chainFood chain
A food web depicts feeding connections in an ecological community. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs...
.
Diet
The diet of the rock sole consists mainly of zoobenthosBenthos
Benthos is the community of organisms which live on, in, or near the seabed, also known as the benthic zone. This community lives in or near marine sedimentary environments, from tidal pools along the foreshore, out to the continental shelf, and then down to the abyssal depths.Many organisms...
organisms such as molluscs, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, brittle star
Brittle star
Brittle stars or ophiuroids are echinoderms in the class Ophiuroidea closely related to starfish. They crawl across the seafloor using their flexible arms for locomotion. The ophiuroids generally have five long slender, whip-like arms which may reach up to in length on the largest specimens...
s, marine worm
Marine worm
Any worm that lives in a marine environment is considered a marine worm. Marine worms are found in several different phyla, including the Platyhelminthes, Nematoda, Annelida , Chaetognatha, Hemichordata, and Phoronida....
s and other fish.
Predators
Rock sole are eaten by marine mammals and other fish, including sharkShark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, Alaska pollock
Alaska pollock
Alaska pollock or walleye pollock is a North Pacific species of the cod family Gadidae. While related to the common Atlantic pollock species of the same family, the Alaska pollock is not a member of the same Pollachius genus.The Norwegian pollock , a rare fish of Norwegian waters, may actually be...
, yellowfin sole
Yellowfin sole
The yellowfin sole, Limanda aspera, is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on soft, sandy bottoms at depths of up to , though it is most commonly found at depths of around...
, Pacific halibut
Pacific halibut
The Pacific halibut is found on the continental shelf of the North Pacific Ocean and Bering sea. They are demersal, living on or near the bottom. The halibut is among the largest teleost fish in the world. Halibut are strong swimmers and are able to migrate long distances...
and Pacific cod
Pacific Cod
The Pacific cod, Gadus macrocephalus, is an important commercial food species. It is also known as gray cod, gray goo, gray wolf, grayest or grayfish. It has three separate dorsal fins, and the catfish-like whiskers on its lower jaw. In appearance, it is similar to the Atlantic Cod...
.
Reproduction
Rock sole reach reproductive maturity at between 4 and 7 years old, and spawnSpawn (biology)
Spawn refers to the eggs and sperm released or deposited, usually into water, by aquatic animals. As a verb, spawn refers to the process of releasing the eggs and sperm, also called spawning...
in winter through to early spring. Eggs are demersal and stick to the surface on which they are laid; hatching takes from 6 to 25 days.
Commercial fishing
The rock sole is fished commercially, and forms an important part of two trawlTrawling
Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net that is used for trawling is called a trawl....
fisheries
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
in the Bering Sea and Gulf of Alaska
Gulf of Alaska
The Gulf of Alaska is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, where Glacier Bay and the Inside Passage are found.The entire shoreline of the Gulf is...
. Although it was overfished
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
in the 1960s stocks have recovered, and the biomass
Biomass (ecology)
Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms,...
of rock sole in the Bering Sea and Aleutian Islands fishery is now estimated to be very high, at twice the level required to support maximum sustainable yield
Sustainable yield in fisheries
The sustainable yield of natural capital is the ecological yield that can be extracted without reducing the base of capital itself, i.e. the surplus required to maintain ecosystem services at the same or increasing level over time. This yield usually varies over time with the needs of the...
. In 2008 the estimated rock sole biomass in the Gulf of Alaska fishery was some 161,617 tons, compared to catches ranging from 1,468 tons in 2004 to 4,260 tons in 2007. Alaska accounts for the majority of the worldwide harvest of this fish, catching over 52,000 tons of rock sole in 2008.
Rock sole fishing off the coast of the United States is managed by the Pacific Fishery Management Council and the North Pacific Fishery Management Council, two of eight U.S. Regional Fishery Management Councils
U.S. Regional Fishery Management Councils
The eight U.S. regional fishery management councils are the primary forums for developing conservation and management measures for U.S. marine fisheries. The regional councils recommend management measures for fisheries in the Exclusive Economic Zone ; which are subject to approval and implemented...
.