Whiskery shark
Encyclopedia
The whiskery shark is a species
of houndshark, family
Triakidae, and the only member of its genus
. This common shark inhabits the Australia
n continental shelf
from Western Australia
to the Bass Strait
, to a depth of 220 m (721.8 ft). It is demersal in habits and prefers rocky and vegetated habitat
s. Stout-bodied and almost "humpbacked" in form, the whiskery shark can be distinguished from all other members of its family by the presence of long nasal barbels
. Its two moderately large dorsal fin
s are roughly equal in size. It is brownish gray above and lighter below, with a pattern of darker saddles and blotches in younger sharks. This species reaches 1.6 m (5.2 ft) in length.
The diet of the whiskery shark consists almost entirely of octopus
es. It is aplacental viviparous; females bear litters of 4–28 pups every other year from August to October, after a gestation period
of 7–9 months. This harmless shark is utilized for its meat, being one of the species marketed as "flake
" in Australia. It is mainly caught by a Western Australian commercial
gillnet
fishery
. Its numbers declined significantly from overfishing
in the 1970s and early 1980s, leading to the introduction of new management measures in the mid-1980s. Since then, strict fishery management has kept the whiskery shark population stable or increasing, resulting in its listing under Least Concern
by the International Union for Conservation of Nature (IUCN).
described the whiskery shark as a new genus and species, Fur macki, in a 1943 issue of the scientific journal
Australian Zoologist. As the name Fur was already in use for the genus Fur of true flies
, in 1951 Whitley replaced it with Furgaleus. The type specimen is a 50 cm (19.7 in) long immature male caught off Mordialloc in Victoria
, Australia
. Other common name
s for the whiskery shark include Mack's whiskery shark, reef shark, shakey shark, and sundowner. Sharks from the western portion of this species' range were once thought to be a separate species, F. ventralis, until comparative studies by Leonard Compagno
found that they were not significantly different from F. macki.
Based on morphology
, Leonard Compagno
grouped Furgaleus with Hemitriakis
, Iago
, and Gogolia as the tribe
Iagini within the subfamily Galeorhininae of the family Triakidae. A 2006 phylogenetic study by J. Andrés López and colleagues, based on four protein
-coding gene
sequences, affirmed that Furgaleus and Hemitriakis are sister taxa
; the study was equivocal regarding the position of Iago and did not include Gogolia.
, the whiskery shark inhabits temperate
continental shelf
waters from the North West Cape
in Western Australia
to Wynyard
in Tasmania
. It is most common in the southwestern portion of its range between Kalbarri
and Albany
, and is rare off Victoria
and Tasmania. Its range seems to encompass a single population. This species is found close to the bottom at depths of up to 220 m (721.8 ft). It favors rocky areas and kelp
beds.
. The horizontally oval eyes are placed high on the head and are equipped with rudimentary nictitating membrane
s (protective third eyelids). Beneath the eye is a prominent ridge, and behind it is a tiny spiracle
. The mouth forms a short, wide arch, and bears somewhat long furrows at the corners. There are 24–32 upper and 36–42 lower tooth rows. Each upper tooth has an angled, knife-like main cusp with smaller cusplets on the trailing side, while each lower tooth has a single upright cusp. There are five pairs of gill slit
s.
The first dorsal fin
is rather large and positioned closer to the pectoral than the pelvic fins, though its origin lies posterior to the pectoral fin rear tips. The second dorsal fin roughly equals the first in size and is positioned slightly ahead of the anal fin, which is much smaller than either dorsal fin. The caudal fin has a short lower lobe and a deep ventral notch near the tip of the upper lobe. Adults are brownish gray above and lighter below; young sharks are lighter in color and have darker saddles and blotches over the body and fins, which fade and may disappear with age. This species grows up to 1.6 m (5.2 ft) long and 13 kg (28.7 lb) in weight.
es and (to a much lesser extent) other cephalopod
s. Bony fishes, small rock lobster
s, spoon worms, and seagrass
have also been found amongst its stomach
contents. A known parasite of this species is the tapeworm Calliobothrium pritchardae.
Like other houndsharks, the whiskery shark is aplacental viviparous; the developing embryo
s are sustained by yolk and probably also maternally produced histotroph. Males can mate every year, while females have a biennial reproductive cycle. Mating
takes place in August and September; females store sperm
until late January to early April of the following year, when the ova
are ready to be ovulated
into the uterus
. After a 7–9 month long gestation period
, litters of 4–28 (average 19) pups are born between August and October. The litter size increases with the size of the female. The newborns measure 22–27 cm (8.7–10.6 in) long. Juveniles are rarely caught by commercial fishers, suggesting that the nursery areas may be found in deeper water or other unfished habitats. Pups double to triple in size in the first 15–17 months of life, and continue to grow rapidly until they are 3–4 years old. Sexual maturity
is attained at a length of 1.1–1.3 m (3.6–4.3 ft) for both sexes, corresponding to around five years of age for males and seven years of age for females. Mature sharks exhibit negligible growth rates, perhaps due to resources being diverted towards reproduction. The maximum lifespan is estimated to be 15 years.
for its meat, which is sold fresh. It is one of the shark species marketed as "flake
". Along with the dusky shark
(Carcharhinus obscurus) and the gummy shark
(Mustelus antarcticus), it is targeted by a shark fishery operating off Western Australia, currently managed as the Western Australian Joint Authority Southern Demersal Gillnet and Demersal Longline Fishery (JASDGDLF). The fishery began in the 1940s with a small number of demersal longline vessels. The whiskery shark was not caught in substantial numbers until the 1970s, with the introduction of monofilament gillnet
s, hydraulic net haulers, and additional vessels. Catches peaked in the early 1980s, when 400–600 tons were taken annually. Overfishing
reduced the population to <30% of pre-exploitation levels by the mid-1980s, prompting the Western Australian government to enact a management plan that stabilized the population at 25–30% of pre-exploitation levels.
In 1995, the management advisory committee for the Western Australian shark fishery recommended that the whiskery shark stock
be rebuilt to 40% of pre-exploitation levels by the 2010/11 season, through a series of fishing effort reductions. Although this target was not met because the effort reductions were not completed until 2000/01, preliminary catch per unit effort
(CPUE) data indicate that the population is increasing. In 2004/05, this species made up 12% (153 tons) of the fishery by weight. The whiskery shark is also a minor catch of the Southern Shark Fishery (SSF), which does not threaten the species overall. Since its population is stable and regularly monitored, and the fisheries that affect it are well-managed, the International Union for Conservation of Nature (IUCN) has assessed this species as Least Concern
.
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 houndshark, 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...
Triakidae, and the only member of its 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...
. This common shark inhabits the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n 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,...
from Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
to the Bass Strait
Bass Strait
Bass Strait is a sea strait separating Tasmania from the south of the Australian mainland, specifically the state of Victoria.-Extent:The International Hydrographic Organization defines the limits of the Bass Strait as follows:...
, to a depth of 220 m (721.8 ft). It is demersal in habits and prefers rocky and vegetated habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s. Stout-bodied and almost "humpbacked" in form, the whiskery shark can be distinguished from all other members of its family by the presence of long nasal barbels
Barbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
. Its two moderately large 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 roughly equal in size. It is brownish gray above and lighter below, with a pattern of darker saddles and blotches in younger sharks. This species reaches 1.6 m (5.2 ft) in length.
The diet of the whiskery shark consists almost entirely of octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
es. It is aplacental viviparous; females bear litters of 4–28 pups every other year from August to October, after a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of 7–9 months. This harmless shark is utilized for its meat, being one of the species marketed as "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...
" in Australia. It is mainly caught by a Western Australian commercial
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...
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...
fishery
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,...
. Its numbers declined significantly 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....
in the 1970s and early 1980s, leading to the introduction of new management measures in the mid-1980s. Since then, strict fishery management has kept the whiskery shark population stable or increasing, resulting in its listing under Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
by the International Union for Conservation of Nature (IUCN).
Taxonomy and phylogeny
Australian ichthyologist Gilbert Percy WhitleyGilbert Percy Whitley
Gilbert Percy Whitley was a British-born Australian ichthyologist and malacologist who was Curator of Fishes at the Australian Museum in Sydney for about 40 years. He was born at Swaythling, Southampton, England, and was educated at King Edward VI School, Southampton and Osborne House...
described the whiskery shark as a new genus and species, Fur macki, in a 1943 issue of the scientific journal
Scientific journal
In academic publishing, a scientific journal is a periodical publication intended to further the progress of science, usually by reporting new research. There are thousands of scientific journals in publication, and many more have been published at various points in the past...
Australian Zoologist. As the name Fur was already in use for the genus Fur of true flies
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
, in 1951 Whitley replaced it with Furgaleus. The type specimen is a 50 cm (19.7 in) long immature male caught off Mordialloc in Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. Other 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...
s for the whiskery shark include Mack's whiskery shark, reef shark, shakey shark, and sundowner. Sharks from the western portion of this species' range were once thought to be a separate species, F. ventralis, until comparative studies by Leonard Compagno
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization of the United Nations.-Career:*Ph.D,...
found that they were not significantly different from F. macki.
Based on morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, Leonard Compagno
Leonard Compagno
Leonard Joseph Victor Compagno is an international authority on shark taxonomy and the author of many scientific papers and books on the subject, best known of which is his 1984 catalogue of shark species produced for the Food and Agriculture Organization of the United Nations.-Career:*Ph.D,...
grouped Furgaleus with Hemitriakis
Hemitriakis
Hemitriakis is a genus of houndshark in the family Triakidae.-Species:* Hemitriakis abdita Compagno & Stevens, 1993 * Hemitriakis complicofasciata Takahashi & Nakaya, 2004...
, Iago
Iago (genus)
Iago is a genus of houndshark in the family Triakidae.The name comes from the villain in Shakespeare´s Othello.-Species:* Iago garricki Fourmanoir & Rivaton, 1979 * Iago omanensis...
, and Gogolia as the tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
Iagini within the subfamily Galeorhininae of the family Triakidae. A 2006 phylogenetic study by J. Andrés López and colleagues, based on four protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
-coding gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
sequences, affirmed that Furgaleus and Hemitriakis are sister 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...
; the study was equivocal regarding the position of Iago and did not include Gogolia.
Distribution and habitat
Endemic to AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, the whiskery shark inhabits temperate
Temperate
In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...
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,...
waters from the North West Cape
North West Cape
North West Cape is a large peninsula of land in the north west coast of Western Australia. Cape Range runs down the spine of the peninsula and Ningaloo Reef runs along the western edge...
in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
to Wynyard
Wynyard, Tasmania
Wynyard is a rural town on the north-west coast of Tasmania, Australia. It lies west of Burnie on the Bass Highway at the mouth of the Inglis River....
in Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
. It is most common in the southwestern portion of its range between Kalbarri
Kalbarri, Western Australia
Kalbarri is a coastal town in the Mid West region located 592 km north of Perth, Western Australia. The town is found at the mouth of the Murchison River and has an elevation of...
and Albany
Albany, Western Australia
Albany is a port city in the Great Southern region of Western Australia, some 418 km SE of Perth, the state capital. As of 2009, Albany's population was estimated at 33,600, making it the 6th-largest city in the state....
, and is rare off Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
and Tasmania. Its range seems to encompass a single population. This species is found close to the bottom at depths of up to 220 m (721.8 ft). It favors rocky areas and kelp
Kelp
Kelps are large seaweeds belonging to the brown algae in the order Laminariales. There are about 30 different genera....
beds.
Description
The whiskery shark has a moderately stout build, with an almost "humpbacked" appearance. The short snout is rounded or wedge-shaped when viewed from above. This species is the only houndshark in which the flaps of skin preceding the nostrils are elongated into thin barbelsBarbel (anatomy)
A barbel on a fish is a slender, whiskerlike tactile organ near the mouth. Fish that have barbels include the catfish, the carp, the goatfish, sturgeon, the zebrafish and some species of shark...
. The horizontally oval eyes are placed high on the head and are equipped with rudimentary nictitating membrane
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...
s (protective third eyelids). Beneath the eye is a prominent ridge, and behind it is a tiny spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
. The mouth forms a short, wide arch, and bears somewhat long furrows at the corners. There are 24–32 upper and 36–42 lower tooth rows. Each upper tooth has an angled, knife-like main cusp with smaller cusplets on the trailing side, while each lower tooth has a single upright cusp. There are 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.
The first 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...
is rather large and positioned closer to the pectoral than the pelvic fins, though its origin lies posterior to the pectoral fin rear tips. The second dorsal fin roughly equals the first in size and is positioned slightly ahead of the anal fin, which is much smaller than either dorsal fin. The caudal fin has a short lower lobe and a deep ventral notch near the tip of the upper lobe. Adults are brownish gray above and lighter below; young sharks are lighter in color and have darker saddles and blotches over the body and fins, which fade and may disappear with age. This species grows up to 1.6 m (5.2 ft) long and 13 kg (28.7 lb) in weight.
Biology and ecology
The whiskery shark is an active and highly specialized predator, with some 95% of its diet consisting of octopusOctopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...
es and (to a much lesser extent) other 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. Bony fishes, small rock lobster
Rock lobster
Jasus edwardsii, the southern rock lobster, red rock lobster, or spiny rock lobster, is a species of spiny lobster found throughout coastal waters of southern Australia and New Zealand including the Chatham Islands. This species is commonly called crayfish or crays in New Zealand and in Māori...
s, spoon worms, and seagrass
Seagrass
Seagrasses are flowering plants from one of four plant families , all in the order Alismatales , which grow in marine, fully saline environments.-Ecology:...
have also been found amongst its stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
contents. A known parasite of this species is the tapeworm Calliobothrium pritchardae.
Like other houndsharks, the whiskery shark is aplacental viviparous; the developing embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s are sustained by yolk and probably also maternally produced histotroph. Males can mate every year, while females have a biennial reproductive cycle. Mating
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
takes place in August and September; females store sperm
Sperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
until late January to early April of the following year, when the ova
Ovum
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...
are ready to be 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...
into the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
. After a 7–9 month long gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
, litters of 4–28 (average 19) pups are born between August and October. The litter size increases with the size of the female. The newborns measure 22–27 cm (8.7–10.6 in) long. Juveniles are rarely caught by commercial fishers, suggesting that the nursery areas may be found in deeper water or other unfished habitats. Pups double to triple in size in the first 15–17 months of life, and continue to grow rapidly until they are 3–4 years old. Sexual maturity
Sexual maturity
Sexual maturity is the age or stage when an organism can reproduce. It is sometimes considered synonymous with adulthood, though the two are distinct...
is attained at a length of 1.1–1.3 m (3.6–4.3 ft) for both sexes, corresponding to around five years of age for males and seven years of age for females. Mature sharks exhibit negligible growth rates, perhaps due to resources being diverted towards reproduction. The maximum lifespan is estimated to be 15 years.
Human interactions
Harmless to humans, the whiskery shark is fished commerciallyCommercial 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...
for its meat, which is sold fresh. It is one of the shark species marketed as "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...
". Along with the dusky shark
Dusky shark
The dusky shark is a species of requiem shark, family Carcharhinidae, occurring in tropical and warm-temperate continental seas worldwide. A generalist apex predator, the dusky shark can be found from the coast to the outer continental shelf and adjacent pelagic waters, and has been recorded from...
(Carcharhinus obscurus) and the gummy shark
Gummy shark
The gummy shark, Mustelus antarcticus, is a shark in the family Triakidae. It is a slender grey shark with white spots along the body and flat plate-like teeth for crushing its prey. It has a maximum length of between 157 cm and 175 cm . It feeds on crustaceans, marine worms, small fish...
(Mustelus antarcticus), it is targeted by a shark fishery operating off Western Australia, currently managed as the Western Australian Joint Authority Southern Demersal Gillnet and Demersal Longline Fishery (JASDGDLF). The fishery began in the 1940s with a small number of demersal longline vessels. The whiskery shark was not caught in substantial numbers until the 1970s, with the introduction of monofilament 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, hydraulic net haulers, and additional vessels. Catches peaked in the early 1980s, when 400–600 tons were taken annually. 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....
reduced the population to <30% of pre-exploitation levels by the mid-1980s, prompting the Western Australian government to enact a management plan that stabilized the population at 25–30% of pre-exploitation levels.
In 1995, the management advisory committee for the Western Australian shark fishery recommended that the whiskery shark stock
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...
be rebuilt to 40% of pre-exploitation levels by the 2010/11 season, through a series of fishing effort reductions. Although this target was not met because the effort reductions were not completed until 2000/01, preliminary catch per unit effort
Catch per unit effort
In fisheries and conservation biology, the catch per unit effort is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species' true abundance...
(CPUE) data indicate that the population is increasing. In 2004/05, this species made up 12% (153 tons) of the fishery by weight. The whiskery shark is also a minor catch of the Southern Shark Fishery (SSF), which does not threaten the species overall. Since its population is stable and regularly monitored, and the fisheries that affect it are well-managed, the International Union for Conservation of Nature (IUCN) has assessed this species as Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.