Balloon shark
Encyclopedia
The balloon shark is a species
of catshark
, family
Scyliorhinidae, endemic to the southwestern Indian Ocean
off South Africa
and Mozambique
. Benthic in nature, it is found over sandy and muddy flats at depths of 40–600 m (131.2–1,968.5 ft). This thick-bodied species has a broad, flattened head and a short tail; its distinguishing traits include narrow, lobe-like skin flaps in front of the nostrils, and a dorsal color pattern of faint darker saddles on a light grayish background.
Befitting its common name
, the balloon shark can inflate itself with water or air as a defense against predators. It feeds on a variety of crustacean
s, cephalopod
s, and fish
es. Reproduction is oviparous, with females producing egg cases two at a time. This species is caught incidentally
in bottom trawls but does not seem to be threatened by fishing pressure, hence its assessment as Least Concern
by the International Union for Conservation of Nature (IUCN).
Annals and Magazine of Natural History. He placed the species within the subgenus Cephaloscyllium
, which later authors have elevated to the rank of full genus. The type specimen measures 75 cm (29.5 in) long and was collected 24–35 km (14.9–21.7 mi) away from the mouth of the Umvoti River in South Africa
.
of KwaZulu-Natal
and Mozambique
. Additional records from the Gulf of Aden
and off Vietnam
appear to represent different, yet-undescribed species. This common, bottom-dwelling shark inhabits the continental shelf
and upper continental slope, at depths of 40–600 m (131.2–1,968.5 ft). It favors sandy and muddy substrates
. There appears to be geographical and/or depth segregation by age: generally only juveniles are found off KwaZulu-Natal at depths of 40–440 m (131.2–1,443.6 ft), suggesting that most adults may be found in deeper and/or more northerly waters.
s (protective third eyelids) and placed rather high on the head. Above and below each eye are ridges, and behind is a small spiracle
. The capacious mouth forms a wide arch and lacks furrows at the corners; the upper teeth are exposed when the mouth is closed. There are around 60 upper and 44 lower tooth rows; each tooth has a strong central cusp flanked on either side by 1–2 tiny cusplets. Of the five pairs of gill slit
s, the third pair is the longest.
The first dorsal fin
is positioned about opposite the pelvic fins; the second dorsal fin is much smaller and placed opposite the anal fin. The pectoral fins are large and broad. The pelvic fins are low; adult males have rather short, thick claspers. The anal fin is smaller than the first dorsal fin but much larger than the second, and is relatively deep. The tail is short, with a deep caudal fin that bears a small lower lobe and a ventral notch near the tip of the upper lobe. The skin is thick and roughened by well-calcified
dermal denticles; each denticle is triangular and pointed. This species is light grayish brown to purplish above, including the upper surface of the pectoral fins, and paler below. A series of 6–7 faint darker saddles are present along the back and tail, which are more obvious in younger sharks. The fins lack obvious lighter margins.
with water or air as a defense mechanism. A juvenile 48 cm (18.9 in) long has been found in the stomach of a coelacanth
(Latimeria chalumnae). The diet of the balloon shark consists mainly of lobster
s, shrimp
s, and cephalopod
s, while bony fishes and other elasmobranchs may also be consumed. It is oviparous, with females producing encapsulated eggs two at a time, one per oviduct
. Deposited eggs have yet to be recovered, implying that spawning occurs in deeper and/or more northerly waters that are frequented by the adults. Young sharks hatch at roughly 20–22 cm (7.9–8.7 in) long; both sexes mature
at approximately 70–75 cm (27.6–29.5 in) long.
and discarded by commercial
bottom trawlers operating in parts of its range, though its population does not yet appear to have been negatively impacted. As a result, the International Union for Conservation of Nature (IUCN) has listed this shark under Least Concern
, while recommending that relevant fisheries
be carefully monitored.
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, endemic to the southwestern Indian Ocean
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
off South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
. Benthic in nature, it is found over sandy and muddy flats at depths of 40–600 m (131.2–1,968.5 ft). This thick-bodied species has a broad, flattened head and a short tail; its distinguishing traits include narrow, lobe-like skin flaps in front of the nostrils, and a dorsal color pattern of faint darker saddles on a light grayish background.
Befitting its 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...
, the balloon shark can inflate itself with water or air as a defense against predators. It feeds on a variety of 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, 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, and fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...
es. Reproduction is oviparous, with females producing egg cases two at a time. This species is caught incidentally
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...
in bottom trawls but does not seem to be threatened by fishing pressure, hence its assessment 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...
by the International Union for Conservation of Nature (IUCN).
Taxonomy
British ichthyologist Charles Tate Regan described the balloon shark as Scyliorhinus sufflans in a 1921 issue of the scientific journalScientific 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...
Annals and Magazine of Natural History. He placed the species within the subgenus Cephaloscyllium
Cephaloscyllium
Cephaloscyllium is a genus of catshark, family Scyliorhinidae, commonly known as swellsharks because of their ability to inflate their body with water or air as a defense against predators. These sluggish, bottom-dwelling sharks are found widely in the tropical and temperate coastal waters of the...
, which later authors have elevated to the rank of full genus. The type specimen measures 75 cm (29.5 in) long and was collected 24–35 km (14.9–21.7 mi) away from the mouth of the Umvoti River in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
.
Distribution and habitat
The range of the balloon shark is likely restricted to the waters off the South African provinceProvinces of South Africa
South Africa is currently divided into nine provinces. On the eve of the 1994 general election, South Africa's former homelands, also known as Bantustans, were reintegrated and the four existing provinces were divided into nine. The twelfth, thirteenth and sixteenth amendments to the constitution...
of KwaZulu-Natal
KwaZulu-Natal
KwaZulu-Natal is a province of South Africa. Prior to 1994, the territory now known as KwaZulu-Natal was made up of the province of Natal and the homeland of KwaZulu....
and Mozambique
Mozambique
Mozambique, officially the Republic of Mozambique , is a country in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west and Swaziland and South Africa to the southwest...
. Additional records from the Gulf of Aden
Gulf of Aden
The Gulf of Aden is located in the Arabian Sea between Yemen, on the south coast of the Arabian Peninsula, and Somalia in the Horn of Africa. In the northwest, it connects with the Red Sea through the Bab-el-Mandeb strait, which is about 20 miles wide....
and off Vietnam
Vietnam
Vietnam – sometimes spelled Viet Nam , officially the Socialist Republic of Vietnam – is the easternmost country on the Indochina Peninsula in Southeast Asia. It is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, and the South China Sea –...
appear to represent different, yet-undescribed species. This common, bottom-dwelling shark inhabits the 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 upper continental slope, at depths of 40–600 m (131.2–1,968.5 ft). It favors sandy and muddy substrates
Substrate (marine biology)
Stream substrate is the material that rests at the bottom of a stream. There are several classification guides. One is:*Mud – silt and clay.*Sand – Particles between 0.06 and 2 mm in diameter.*Granule – Between 2 and 4 mm in diameter....
. There appears to be geographical and/or depth segregation by age: generally only juveniles are found off KwaZulu-Natal at depths of 40–440 m (131.2–1,443.6 ft), suggesting that most adults may be found in deeper and/or more northerly waters.
Description
Reaching 1.1 m (3.6 ft) long, the balloon shark has a stout, firm body and a broad, flattened head. The snout is short and rounded, with each nostril divided by a narrow lobe on its anterior rim. The horizontally oval eyes are equipped with rudimentary nictitating membraneNictitating 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) and placed rather high on the head. Above and below each eye are ridges, and behind is a small 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 capacious mouth forms a wide arch and lacks furrows at the corners; the upper teeth are exposed when the mouth is closed. There are around 60 upper and 44 lower tooth rows; each tooth has a strong central cusp flanked on either side by 1–2 tiny cusplets. Of 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, the third pair is the longest.
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 positioned about opposite the pelvic fins; the second dorsal fin is much smaller and placed opposite the anal fin. The pectoral fins are large and broad. The pelvic fins are low; adult males have rather short, thick claspers. The anal fin is smaller than the first dorsal fin but much larger than the second, and is relatively deep. The tail is short, with a deep caudal fin that bears a small lower lobe and a ventral notch near the tip of the upper lobe. The skin is thick and roughened by well-calcified
Calcification
Calcification is the process in which calcium salts build up in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification.-Causes:...
dermal denticles; each denticle is triangular and pointed. This species is light grayish brown to purplish above, including the upper surface of the pectoral fins, and paler below. A series of 6–7 faint darker saddles are present along the back and tail, which are more obvious in younger sharks. The fins lack obvious lighter margins.
Biology and ecology
Like other members of its genus, the balloon shark is capable of greatly inflating its stomachStomach
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...
with water or air as a defense mechanism. A juvenile 48 cm (18.9 in) long has been found in the stomach of a coelacanth
Latimeria chalumnae
West Indian Ocean coelacanth is a species of coelacanth, known for its vivid blue pigment. It is the better known of the two extant species.-Biological characteristics:...
(Latimeria chalumnae). The diet of the balloon shark consists mainly of lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...
s, 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...
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, while bony fishes and other elasmobranchs may also be consumed. It is oviparous, with females producing encapsulated eggs two at a time, one per 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...
. Deposited eggs have yet to be recovered, implying that spawning occurs in deeper and/or more northerly waters that are frequented by the adults. Young sharks hatch at roughly 20–22 cm (7.9–8.7 in) long; both sexes mature
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...
at approximately 70–75 cm (27.6–29.5 in) long.
Human interactions
The balloon shark has almost no economic value, though the skin may be utilized. It is regularly caught incidentallyBycatch
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...
and discarded by 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...
bottom trawlers operating in parts of its range, though its population does not yet appear to have been negatively impacted. As a result, the International Union for Conservation of Nature (IUCN) has listed this shark 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...
, while recommending that relevant 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,...
be carefully monitored.