Nursehound
Encyclopedia
The nursehound also known as the large-spotted dogfish, greater spotted dogfish, or bull huss, is a species
of catshark
, family
Scyliorhinidae, found in the northeastern Atlantic Ocean
. It is generally found amongst rocks or algae
at a depth of 20–60 m (65.6–196.9 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fin
s placed far back. It shares its range with the more common and closely related small-spotted catshark
(S. canicula), which it resembles in appearance but can be distinguished from in having larger spots and nasal skin flaps that do not extend to the mouth.
Nursehounds have nocturnal habits and generally hide inside small holes during the day, often associating with other members of its species. A benthic predator, it feeds on a range of bony fishes, smaller sharks, crustacean
s, and cephalopod
s. Like other catsharks, the nursehound is oviparous in reproduction. Females deposit large, thick-walled egg cases, two at a time, from March to October, securing them to bunches of seaweed
. The eggs take 7–12 months to hatch. Nursehounds are marketed as food in several Europe
an countries under various names, including "flake", "catfish", "rock eel", and "rock salmon". It was once also valued for its rough skin (called "rubskin"), which was used as an abrasive
. The International Union for Conservation of Nature (IUCN) has assessed the nursehound as Near Threatened
, as its population in the Mediterranean Sea
seems to have declined substantially from overfishing
.
of Systema Naturae
. He gave it the name Squalus stellaris, the specific epithet stellaris being Latin
for "starry". No type specimen was designated. In 1973, Stewart Springer
moved this species to the genus Scyliorhinus. The common name
"nursehound" came from an old belief by English fishermen that this shark attends to its smaller relatives, while the name "huss" may have came from a distortion of the word "nurse" over time.
and Sweden
to Senegal
, including off the British Isles
, throughout the Mediterranean Sea
, and the Canary Islands. It may occur as far south as the mouth of the Congo River
, though these West Africa
n records may represent misidentifications of the West African catshark
(S. cervigoni). Its range seems to be rather patchy, particularly around offshore islands, where there are small local populations with limited exchange between them. The nursehound can be found from the intertidal zone
to a depth of 400 m (1,312.3 ft), though it is most common between 20 m (65.6 ft) and 60–125 m (196.9–410.1 ft). This bottom-dwelling species prefers quiet water over rough or rocky terrain, including sites with algal cover. In the Mediterranean, it favors algae-covered coral
.
The nursehound attains a length of 1.6 m (5.2 ft), though most measure less than 1.3 m (4.3 ft). This shark has a broad, rounded head and a stout body that tapers towards the tail. The eyes are oval in shape, with a thick fold of skin on the lower rim but no nictitating membrane
. Unlike in the small-spotted catshark, the large flaps of skin beside the nares do not reach the mouth. In the upper jaw, there are 22–27 tooth rows on either side and 0–2 teeth at the symphysis (center); in the lower jaw, there are 18–21 tooth rows on either side and 2–4 teeth at the symphysis. The teeth are Y-shaped and smooth-edged; the anterior teeth have a single central cusp, while the posterior teeth have an additional pair of lateral cusplets. Towards the rear of the jaws, the teeth become progressively smaller and more angled, with proportionately larger lateral cusplets. The five pairs of gill slit
s are small, with the last two over the pectoral fin bases.
The two dorsal fin
s are placed far back on the body; the first is larger than the second and originates over the bases of the pelvic fins. The pectoral fins are large. In males, the inner margins of the pelvic fins are merged into an "apron" over the claspers. The caudal fin is broad and nearly horizontal, with an indistinct lower lobe. The skin is very rough, due to a covering of large, upright dermal denticles. The nursehound has small black dots covering its back and sides, interspersed with brown spots of varying shapes larger than the pupil
, on a grayish or brownish background. The pattern is highly variable across individuals and ages; there may also be white spots, or the brown spots may be expanded so that almost the whole body is dark, or a series of faint "saddles" may be present. The underside is plain white.
. In captivity, these sharks are gregarious and tend to rest in groups, though the individuals comprising any particular group changes frequently. This species is less common than the small-spotted catshark
.
The nursehound feeds on a variety of benthic organisms, including bony fishes such mackerel
, deepwater cardinalfishes, dragonet
s, gurnard
s, flatfish
es, and herring
, and smaller sharks such as the small-spotted catshark. It also consumes crustacean
s, in particular crab
s but also hermit crab
s and large shrimp
, and cephalopod
s. Given the opportunity, this shark will scavenge
. Adults consume relatively more bony fish and cephalopods, and fewer crustaceans, than juveniles. Known parasites of this species include the monogenea
ns Hexabothrium appendiculatum and Leptocotyle major, the tapeworm Acanthobothrium coronatum, the trypanosome
Trypanosoma scyllii, the isopod Ceratothoa oxyrrhynchaena, and the copepod
Lernaeopoda galei. The netted dog whelk
(Nassarius reticulatus) preys on the nursehound's eggs by piercing the case and extracting the yolk.
Like other members of its family, the nursehound is oviparous. Known breeding grounds include the River Fal
estuary
and Wembury Bay
in England
. Adults move into shallow water in the spring or early summer, and mate only at night. The eggs are deposited in the shallows from March to October. Although a single female produces 77–109 oocyte
s per year, not all of these are ovulated
and estimates of the actual number of eggs laid range from 9 to 41. The eggs mature and are released two at a time, one from each oviduct
. Each egg is enclosed in a thick, dark brown case measuring 10–13 cm (3.9–5.1 in) long and 3.5 cm (1.4 in) wide. There are tendrils at the four corners, that allow the female to secure the egg cases to bunches of seaweed (usually Cystoseira
spp. or Laminaria saccharina
).
Eggs in the North Sea
and the Atlantic take 10–12 months to hatch, while those from the southern Mediterranean take 7 months to hatch. The length at hatching is 16 cm (6.3 in) off Britain, and 10–12 cm (3.9–4.7 in) off France
. Newly hatched sharks grow at a rate of 0.45–0.56 mm (0.0177165354330709–0.0220472440944882 in) per day, and have prominent saddle markings. Sexual maturity is attained at a length of 77–79 cm (30.3–31.1 in), which corresponds to an age of four years if hatchling growth rates remain constant. This species has a lifespan of at least 19 years.
Nursehounds are generally harmless to humans. However, 19th-century British naturalist
Jonathan Couch
noted that "although not so formidable with its teeth as many other sharks, this fish is well able to defend itself from an enemy. When seized it throws its body round the arm that holds it, and by a contractile and reversed action of its body grates over the surface of its enemy with the rugged spines of its skin, like a rasp. There are few animals that can bear so severe an infliction, by which their surface is torn with lacerated wounds." This shark is displayed by many public aquarium
s and has been bred in captivity.
The rough skin (called "rubskin") of the nursehound was once used to polish wood
and alabaster
, to smooth arrow
s and barrel
s, and to raise the hairs of beaver hat
s as a replacement for pumice
. Rubskin was so valued that a pound of it was worth a hundredweight
of sandpaper
. The liver
was also used as a source of oil
, and the carcasses cut up and used to bait crab traps. The meat of this species is marketed fresh or dried and salted, though it is considered "coarse" in some quarters. In the United Kingdom
(UK}, it is one of the species sold under the names "flake
", "catfish", "rock eel", or "rock salmon
". In France, it is sold as grande rousette or saumonette, as after being skinned and beheaded it resembles salmon
. This species is also sometimes processed into fishmeal, or its fins dried and exported to the Asian market. In European waters, commercial production
of this species is led by France, followed by the UK and Portugal
; it is caught using bottom trawls, gillnet
s, bottom set longlines, handlines and fixed bottom nets. In 2004, a total catch of 208 tons was reported from the northeastern Atlantic.
The impact of fishing activities on the nursehound is difficult to assess as species-specific data is generally lacking. This species is more susceptible to overfishing
than the small-spotted catshark because of its larger size and fragmented distribution, which limits the recovery potential of depleted local stocks
. There is evidence that its numbers have declined significantly in the Gulf of Lion
, off Albania
, and around the Balearic Islands
. In the upper Tyrrhenian Sea
, its numbers have fallen by over 99% since the 1970s. These declines have led the International Union for Conservation of Nature (IUCN) to list the nursehound under Near Threatened
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of catshark
Catshark
Catsharks are ground sharks of the family Scyliorhinidae, with over 150 known species. While they are generally known as catsharks, many species are commonly called dogfish....
, family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Scyliorhinidae, found in the northeastern Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. It is generally found amongst rocks or algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
at a depth of 20–60 m (65.6–196.9 ft). Growing up to 1.6 m (5.2 ft) long, the nursehound has a robust body with a broad, rounded head and two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s placed far back. It shares its range with the more common and closely related small-spotted catshark
Small-spotted catshark
The small-spotted catshark or lesser spotted dogfish, Scyliorhinus canicula, is a cat shark of the family Scyliorhinidae found on the continental shelves and uppermost slopes off Norway and the British Isles south to Senegal, including the Mediterranean between latitudes 63° N and 12° N. Its...
(S. canicula), which it resembles in appearance but can be distinguished from in having larger spots and nasal skin flaps that do not extend to the mouth.
Nursehounds have nocturnal habits and generally hide inside small holes during the day, often associating with other members of its species. A benthic predator, it feeds on a range of bony fishes, smaller sharks, 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, and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s. Like other catsharks, the nursehound is oviparous in reproduction. Females deposit large, thick-walled egg cases, two at a time, from March to October, securing them to bunches of seaweed
Seaweed
Seaweed is a loose, colloquial term encompassing macroscopic, multicellular, benthic marine algae. The term includes some members of the red, brown and green algae...
. The eggs take 7–12 months to hatch. Nursehounds are marketed as food in several Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
an countries under various names, including "flake", "catfish", "rock eel", and "rock salmon". It was once also valued for its rough skin (called "rubskin"), which was used as an abrasive
Abrasive
An abrasive is a material, often a mineral, that is used to shape or finish a workpiece through rubbing which leads to part of the workpiece being worn away...
. The International Union for Conservation of Nature (IUCN) has assessed the nursehound as Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
, as its population in the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
seems to have declined substantially from overfishing
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....
.
Taxonomy
The first scientific description of the nursehound was published by Carl Linnaeus, in the 1758 tenth edition10th edition of Systema Naturae
The 10th edition of Systema Naturae was a book written by Carl Linnaeus and published in two volumes in 1758 and 1759, which marks the starting point of zoological nomenclature...
of Systema Naturae
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
. He gave it the name Squalus stellaris, the specific epithet stellaris being Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for "starry". No type specimen was designated. In 1973, Stewart Springer
Stewart Springer
Stewart Springer, was a world renowned expert on shark behavior, classification , and distribution of shark populations. There are more than 35 species of sharks, skates, rays, and other animals either classified originally by him or named after him.-Education:Springer was a field naturalist,...
moved this species to the genus Scyliorhinus. The common name
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
"nursehound" came from an old belief by English fishermen that this shark attends to its smaller relatives, while the name "huss" may have came from a distortion of the word "nurse" over time.
Distribution and habitat
The nursehound is found in the northeastern Atlantic from southern NorwayNorway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...
and Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
to Senegal
Senegal
Senegal , officially the Republic of Senegal , is a country in western Africa. It owes its name to the Sénégal River that borders it to the east and north...
, including off the British Isles
British Isles
The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...
, throughout the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, and the Canary Islands. It may occur as far south as the mouth of the Congo River
Congo River
The Congo River is a river in Africa, and is the deepest river in the world, with measured depths in excess of . It is the second largest river in the world by volume of water discharged, though it has only one-fifth the volume of the world's largest river, the Amazon...
, though these West Africa
West Africa
West Africa or Western Africa is the westernmost region of the African continent. Geopolitically, the UN definition of Western Africa includes the following 16 countries and an area of approximately 5 million square km:-Flags of West Africa:...
n records may represent misidentifications of the West African catshark
West African catshark
The West African catshark, Scyliorhinus cervigoni, is a cat shark of the family Scyliorhinidae found from the eastern Atlantic between latitudes 20° N and 17° S, at depths between 45 and 500 m. Its length is up to 67 cm...
(S. cervigoni). Its range seems to be rather patchy, particularly around offshore islands, where there are small local populations with limited exchange between them. The nursehound can be found from the intertidal zone
Intertidal zone
The intertidal zone is the area that is above water at low tide and under water at high tide . This area can include many different types of habitats, with many types of animals like starfish, sea urchins, and some species of coral...
to a depth of 400 m (1,312.3 ft), though it is most common between 20 m (65.6 ft) and 60–125 m (196.9–410.1 ft). This bottom-dwelling species prefers quiet water over rough or rocky terrain, including sites with algal cover. In the Mediterranean, it favors algae-covered coral
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
.
Description
Nictitating membrane
The nictitating membrane is a transparent or translucent third eyelid present in some animals that can be drawn across the eye for protection and to moisten it while maintaining visibility. Some reptiles, birds, and sharks have a full nictitating membrane; in many mammals, there is a small...
. Unlike in the small-spotted catshark, the large flaps of skin beside the nares do not reach the mouth. In the upper jaw, there are 22–27 tooth rows on either side and 0–2 teeth at the symphysis (center); in the lower jaw, there are 18–21 tooth rows on either side and 2–4 teeth at the symphysis. The teeth are Y-shaped and smooth-edged; the anterior teeth have a single central cusp, while the posterior teeth have an additional pair of lateral cusplets. Towards the rear of the jaws, the teeth become progressively smaller and more angled, with proportionately larger lateral cusplets. The five pairs of gill slit
Gill slit
Gill slits are individual openings to gills, i.e., multiple gill arches, which lack a single outer cover. Such gills are characteristic of Cartilaginous fish such as sharks, rays, sawfish, and guitarfish. Most of these have five pairs, but a few species have 6 or 7 pairs...
s are small, with the last two over the pectoral fin bases.
The two dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
s are placed far back on the body; the first is larger than the second and originates over the bases of the pelvic fins. The pectoral fins are large. In males, the inner margins of the pelvic fins are merged into an "apron" over the claspers. The caudal fin is broad and nearly horizontal, with an indistinct lower lobe. The skin is very rough, due to a covering of large, upright dermal denticles. The nursehound has small black dots covering its back and sides, interspersed with brown spots of varying shapes larger than the pupil
Pupil
The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
, on a grayish or brownish background. The pattern is highly variable across individuals and ages; there may also be white spots, or the brown spots may be expanded so that almost the whole body is dark, or a series of faint "saddles" may be present. The underside is plain white.
Biology and ecology
Primarily nocturnal, nursehounds spend the day inside small holes in rocks and swim into deeper water at night to hunt. Sometimes two sharks will squeeze into the same hole, and several individuals will seek out refuges within the same local area. In one tracking study, a single immature nursehound was observed to use five different refuges in succession over a period of 168 days, consistently returning to each one over a number of days before moving on. Nursehounds may occupy refuges to hide from predators, avoid harassment by mature conspecifics, and/or to facilitate thermoregulationThermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different...
. In captivity, these sharks are gregarious and tend to rest in groups, though the individuals comprising any particular group changes frequently. This species is less common than the small-spotted catshark
Small-spotted catshark
The small-spotted catshark or lesser spotted dogfish, Scyliorhinus canicula, is a cat shark of the family Scyliorhinidae found on the continental shelves and uppermost slopes off Norway and the British Isles south to Senegal, including the Mediterranean between latitudes 63° N and 12° N. Its...
.
The nursehound feeds on a variety of benthic organisms, including bony fishes such mackerel
Mackerel
Mackerel is a common name applied to a number of different species of fish, mostly, but not exclusively, from the family Scombridae. They may be found in all tropical and temperate seas. Most live offshore in the oceanic environment but a few, like the Spanish mackerel , enter bays and can be...
, deepwater cardinalfishes, dragonet
Dragonet
Dragonets are small, perciform, marine fish of the diverse family Callionymidae . Found mainly in the tropical waters of the western Indo-Pacific, the family contains approximately 186 species in 18 genera. The Draconettidae may be considered a sister family, whose members are very much alike,...
s, gurnard
Gurnard
-Fish:*Sea robin, fish of the family Triglidae, including:**Bluefin gurnard**Tub gurnard**Red gurnard**Grey gurnard**Scaly gurnard**Eastern spiny gurnard**Spotted gurnard...
s, flatfish
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...
es, and herring
Herring
Herring is an oily fish of the genus Clupea, found in the shallow, temperate waters of the North Pacific and the North Atlantic oceans, including the Baltic Sea. Three species of Clupea are recognized. The main taxa, the Atlantic herring and the Pacific herring may each be divided into subspecies...
, and smaller sharks such as the small-spotted catshark. It also consumes 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, in particular crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
s but also hermit crab
Hermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
s and large shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
, and cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s. Given the opportunity, this shark will scavenge
Scavenger
Scavenging is both a carnivorous and herbivorous feeding behavior in which individual scavengers search out dead animal and dead plant biomass on which to feed. The eating of carrion from the same species is referred to as cannibalism. Scavengers play an important role in the ecosystem by...
. Adults consume relatively more bony fish and cephalopods, and fewer crustaceans, than juveniles. Known parasites of this species include the monogenea
Monogenea
Monogenea are a group of largely ectoparasitic members of the flatworm phylum Platyhelminthes, class Monogenea.-Characteristics:Monogenea are very small parasitic flatworms mainly found on skin or gills of fish....
ns Hexabothrium appendiculatum and Leptocotyle major, the tapeworm Acanthobothrium coronatum, the trypanosome
Trypanosoma
Trypanosoma is a genus of kinetoplastids , a monophyletic group of unicellular parasitic flagellate protozoa. The name is derived from the Greek trypano and soma because of their corkscrew-like motion. All trypanosomes are heteroxenous and are transmitted via a vector...
Trypanosoma scyllii, the isopod Ceratothoa oxyrrhynchaena, and the copepod
Copepod
Copepods are a group of small crustaceans found in the sea and nearly every freshwater habitat. Some species are planktonic , some are benthic , and some continental species may live in limno-terrestrial habitats and other wet terrestrial places, such as swamps, under leaf fall in wet forests,...
Lernaeopoda galei. The netted dog whelk
Nassarius reticulatus
Nassarius reticulatus, common name the "netted dog whelk" is a species of small European sea snail, a marine gastropod mollusc in the family Nassariidae, the dog whelks or nassa mud snails.- External links :*...
(Nassarius reticulatus) preys on the nursehound's eggs by piercing the case and extracting the yolk.
Life history
River Fal
The River Fal flows through Cornwall, United Kingdom, rising on the Goss Moor and reaching the English Channel at Falmouth. On or near the banks of the Fal are the castles of Pendennis and St Mawes as well as Trelissick Garden. The River Fal separates the Roseland peninsula from the rest of...
estuary
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
and Wembury Bay
Wembury
Wembury is a village on the south coast of Devon, very close to Plymouth Sound. Wembury is also the name of the peninsula in which the village is situated. The village lies in the administrative district of the South Hams within the South Devon Area of Outstanding Natural Beauty . The South West...
in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. Adults move into shallow water in the spring or early summer, and mate only at night. The eggs are deposited in the shallows from March to October. Although a single female produces 77–109 oocyte
Oocyte
An oocyte, ovocyte, or rarely ocyte, is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in the ovary during female gametogenesis. The female germ cells produce a primordial germ cell which undergoes a mitotic...
s per year, not all of these are ovulated
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
and estimates of the actual number of eggs laid range from 9 to 41. The eggs mature and are released two at a time, one from each oviduct
Oviduct
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...
. Each egg is enclosed in a thick, dark brown case measuring 10–13 cm (3.9–5.1 in) long and 3.5 cm (1.4 in) wide. There are tendrils at the four corners, that allow the female to secure the egg cases to bunches of seaweed (usually Cystoseira
Cystoseira
Cystoseira is a genus of brown algae in the order Fucales.-Description:Cystoseira is characterized by highly differentiated basal and apical regions and the presence of catenate pneumatocysts ....
spp. or Laminaria saccharina
Laminaria saccharina
Saccharina latissima is a brown algae , of the family Laminariaceae. It is also known by the common name sea belt. It is found in the north east Atlantic Ocean and the Barents Sea south to Galicia in Spain. It is not found in the Bay of Biscay but is common round the coasts of the British...
).
Eggs in the North Sea
North Sea
In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...
and the Atlantic take 10–12 months to hatch, while those from the southern Mediterranean take 7 months to hatch. The length at hatching is 16 cm (6.3 in) off Britain, and 10–12 cm (3.9–4.7 in) off France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
. Newly hatched sharks grow at a rate of 0.45–0.56 mm (0.0177165354330709–0.0220472440944882 in) per day, and have prominent saddle markings. Sexual maturity is attained at a length of 77–79 cm (30.3–31.1 in), which corresponds to an age of four years if hatchling growth rates remain constant. This species has a lifespan of at least 19 years.
Human interactions
Naturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
Jonathan Couch
Jonathan Couch
Jonathan Couch was a British naturalist, the only child of Richard and Philippa Couch, of a family long resident at Polperro, a small fishing village between Looe and Fowey, on the south coast of Cornwall.-Biography:...
noted that "although not so formidable with its teeth as many other sharks, this fish is well able to defend itself from an enemy. When seized it throws its body round the arm that holds it, and by a contractile and reversed action of its body grates over the surface of its enemy with the rugged spines of its skin, like a rasp. There are few animals that can bear so severe an infliction, by which their surface is torn with lacerated wounds." This shark is displayed by many public aquarium
Public aquarium
A public aquarium is the aquatic counterpart of a zoo, housing living aquatic species for viewing. Most public aquariums feature tanks larger than those kept by home aquarists, as well as smaller tanks. Since the first public aquariums were built in the mid-19th century, they have become popular...
s and has been bred in captivity.
The rough skin (called "rubskin") of the nursehound was once used to polish wood
Wood
Wood is a hard, fibrous tissue found in many trees. It has been used for hundreds of thousands of years for both fuel and as a construction material. It is an organic material, a natural composite of cellulose fibers embedded in a matrix of lignin which resists compression...
and alabaster
Alabaster
Alabaster is a name applied to varieties of two distinct minerals, when used as a material: gypsum and calcite . The former is the alabaster of the present day; generally, the latter is the alabaster of the ancients...
, to smooth arrow
Arrow
An arrow is a shafted projectile that is shot with a bow. It predates recorded history and is common to most cultures.An arrow usually consists of a shaft with an arrowhead attached to the front end, with fletchings and a nock at the other.- History:...
s and barrel
Barrel
A barrel or cask is a hollow cylindrical container, traditionally made of vertical wooden staves and bound by wooden or metal hoops. Traditionally, the barrel was a standard size of measure referring to a set capacity or weight of a given commodity. A small barrel is called a keg.For example, a...
s, and to raise the hairs of beaver hat
Beaver hat
A beaver hat is a hat made from felted beaver fur. They were fashionable across much of Europe during the period 1550-1850 because the soft yet resilient material could be easily combed to make a variety of hat shapes...
s as a replacement for pumice
Pumice
Pumice is a textural term for a volcanic rock that is a solidified frothy lava typically created when super-heated, highly pressurized rock is violently ejected from a volcano. It can be formed when lava and water are mixed. This unusual formation is due to the simultaneous actions of rapid...
. Rubskin was so valued that a pound of it was worth a hundredweight
Hundredweight
The hundredweight or centum weight is a unit of mass defined in terms of the pound . The definition used in Britain differs from that used in North America. The two are distinguished by the terms long hundredweight and short hundredweight:* The long hundredweight is defined as 112 lb, which...
of sandpaper
Sandpaper
Sandpaper, also known as glasspaper, is a heavy paper with abrasive material attached to its surface.Sandpaper is part of the "coated abrasives" family of abrasive products. It is used to remove small amounts of material from surfaces, either to make them smoother , to remove a layer of material...
. The liver
Liver
The liver is a vital organ present in vertebrates and some other animals. It has a wide range of functions, including detoxification, protein synthesis, and production of biochemicals necessary for digestion...
was also used as a source of oil
Shark liver oil
Shark liver oil is obtained from sharks that are caught for food purposes and are living in cold, deep oceans. The liver oil from sharks has been used by fishermen for centuries as a folk remedy for general health...
, and the carcasses cut up and used to bait crab traps. The meat of this species is marketed fresh or dried and salted, though it is considered "coarse" in some quarters. In the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
(UK}, it is one of the species sold under the names "flake
Flake (fish)
Flake is a term used in Australia to indicate the flesh of any of several species of small shark, particularly Gummy shark. The term probably arose in the late 1920s when the large-scale commercial shark fishery off the coast of Victoria was established. Until that time, shark was generally an...
", "catfish", "rock eel", or "rock salmon
Rock salmon
Rock salmon refers to either of two kinds of fish:The first, also called rock eel, flake, and huss in the UK, is any one of many species of small shark, including the spiny dogfish or the bull huss .Rock salmon is consumed in many European countries and is often sold by fish and chip shops in the...
". In France, it is sold as grande rousette or saumonette, as after being skinned and beheaded it resembles salmon
Salmon
Salmon is the common name for several species of fish in the family Salmonidae. Several other fish in the same family are called trout; the difference is often said to be that salmon migrate and trout are resident, but this distinction does not strictly hold true...
. This species is also sometimes processed into fishmeal, or its fins dried and exported to the Asian market. In European waters, commercial production
Commercial fishing
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions...
of this species is led by France, followed by the UK and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
; it is caught using bottom trawls, gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
s, bottom set longlines, handlines and fixed bottom nets. In 2004, a total catch of 208 tons was reported from the northeastern Atlantic.
The impact of fishing activities on the nursehound is difficult to assess as species-specific data is generally lacking. This species is more susceptible to overfishing
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....
than the small-spotted catshark because of its larger size and fragmented distribution, which limits the recovery potential of depleted local stocks
Fish stock
Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters are the only significant factors in determining population dynamics, while extrinsic factors are considered to be insignificant.-The stock concept:All species have geographic limits to their...
. There is evidence that its numbers have declined significantly in the Gulf of Lion
Gulf of Lion
The Gulf of Lion is a wide embayment of the Mediterranean coastline of Languedoc-Roussillon and Provence in France, reaching from the border with Catalonia in the west to Toulon.The chief...
, off Albania
Albania
Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...
, and around the Balearic Islands
Balearic Islands
The Balearic Islands are an archipelago of Spain in the western Mediterranean Sea, near the eastern coast of the Iberian Peninsula.The four largest islands are: Majorca, Minorca, Ibiza and Formentera. The archipelago forms an autonomous community and a province of Spain with Palma as the capital...
. In the upper Tyrrhenian Sea
Tyrrhenian Sea
The Tyrrhenian Sea is part of the Mediterranean Sea off the western coast of Italy.-Geography:The sea is bounded by Corsica and Sardinia , Tuscany, Lazio, Campania, Basilicata and Calabria and Sicily ....
, its numbers have fallen by over 99% since the 1970s. These declines have led the International Union for Conservation of Nature (IUCN) to list the nursehound under Near Threatened
Near Threatened
Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...
.