The streamlined spinefoot (''Siganus argenteus''), also known as the forktail rabbitfish, schooling rabbitfish or silver spinefoot, is a species of marine

ray-finned fish Actinopterygii (; ), members of which are known as ray-finned fish or actinopterygians, is a class of bony fish that comprise over 50% of living vertebrate species. They are so called because of their lightly built fins made of webbings of sk ...

, a

rabbitfish Rabbitfishes or spinefoots, genus ''Siganus'', are perciform fishes in the family (biology), family Siganidae. It is the only Extant taxon, extant genus in its family and has 29 species. In some now obsolete classifications, the species having ...

belonging to the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Siganidae Siganidae, the rabbitfishes, are a small family of ray-finned fishes in the order Perciformes. The only extant genus is '' Siganus'', the rabbitfish and spinefoot. However, a number of genera are known from fossils. The extant species are marine ...

. It is found in the

Indo-Pacific The Indo-Pacific is a vast biogeographic region of Earth. In a narrow sense, sometimes known as the Indo-West Pacific or Indo-Pacific Asia, it comprises the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the ...

region.

Taxonomy

The streamlined spinefoot was first formally described in 1825 as ''Amphacanthus argenteus'' by the French

naturalists Natural history is a domain of inquiry involving organisms, including animals, fungi, and plants, in their natural environment, leaning more towards observational than experimental methods of study. A person who studies natural history is cal ...

Jean René Constant Quoy Jean René Constant Quoy (10 November 1790 in Maillé, Vendée, Maillé – 4 July 1869 in Rochefort, Charente-Maritime, Rochefort) was a French naval surgeon, zoologist and anatomist. In 1806, he began his medical studies at the school of naval ...

and

Joseph Paul Gaimard Joseph Paul Gaimard (31 January 1793 – 10 December 1858) was a French naval surgeon and naturalist. Biography Gaimard was born at Saint-Zacharie on January 31, 1793. He studied medicine at the naval medical school in Toulon, subsequen ...

with the type locality given as

Guam Guam ( ; ) is an island that is an Territories of the United States, organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. Guam's capital is Hagåtña, Guam, Hagåtña, and the most ...

in the

Marianas The Mariana Islands ( ; ), also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fifteen longitudinally oriented, mostly Volcano#Dormant and reactivated, dormant volcanic mountains in the northwestern Pacific Ocean ...

. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

''argenteus'' means "silvery", a reference to the silver colour of the cheeks and lower body.

Description

The streamlined spinefoot has a body which is oval, compressed, slender and

fusiform Fusiform (from Latin ''fusus'' ‘spindle’) means having a spindle (textiles), spindle-like shape that is wide in the middle and tapers at both ends. It is similar to the lemon (geometry), lemon-shape, but often implies a focal broadening of a ...

, the body has a

standard length Fish measurement is the measuring of individual fish and various parts of fish anatomy, their anatomies, for data used in many areas of ichthyology, including Taxonomy (biology), taxonomy and fishery biology. Overall length Standard length (SL) is ...

which is 2.4 to 3 times its depth. The small head does not have a steep dorsal profile byt has a pointed snout. The front nostril has a flap which extends past the rear nostril. There is a procumbent spine at the front of the

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

which is enclosed in the skin of the nape. The dorsal fin contains 13 spines and 10 soft rays while the

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

has 7 spines and 9 soft rays. The

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

has a deep fork. This species attains a maximum

total length Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured f ...

of , although is more typical. The colours of this species are that blue on the upper body with a silvery lower body. They frequently have variable markings, spots and curved lines, particularly on the lower flanks. The eye has a silvery-yellow iris. The axil of

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

is yellow and there is normally a yellow stripe along the base of the dorsal fin. There is also a dark brown bar on the upper edge of the operculum. This fish changes colour when alarmed or asleep to pale and dark brown mottling, with dark areas forming 7 diagonal zones across the flanks and the fins becoming mottled.

Distribution and habitat

The streamlined spinefoot has a wide Indo-Pacific distribution from the Red Sea south to Mozambique and Madagascar and east into the Pacific Ocean as far as Pitcairn Island, north to Japan and south to Australia. In Australia it is distributed from the area of

Shark Bay Shark Bay () is a World Heritage Site in the Gascoyne region of Western Australia. The area is located approximately north of Perth, on the westernmost point of the Australian continent. UNESCO's listing of Shark Bay as a World Heritage S ...

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

to the

Ashmore Reef The Territory of Ashmore and Cartier Islands is an uninhabited Australian external territory consisting of four low-lying tropical islands in two separate reefs (Ashmore and Cartier), as well as the territorial sea generated by the islands ...

in the

Timor Sea The Timor Sea (, , or ) is a relatively shallow sea in the Indian Ocean bounded to the north by the island of Timor with Timor-Leste to the north, Indonesia to the northwest, Arafura Sea to the east, and to the south by Australia. The Sunda Tr ...

, and on the east coast from the northern

Great Barrier Reef The Great Barrier Reef is the world's largest coral reef system, composed of over 2,900 individual reefs and 900 islands stretching for over over an area of approximately . The reef is located in the Coral Sea, off the coast of Queensland, ...

near Cape York south to

Moreton Bay Moreton Bay is a bay located on the eastern coast of Australia from central Brisbane, Queensland. It is one of Queensland's most important coastal resources. The waters of Moreton Bay are a popular destination for recreational anglers and are ...

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

, it also occurs on reefs in the

Coral Sea The Coral Sea () is a marginal sea of the Pacific Ocean, South Pacific off the northeast coast of Australia, and classified as an Interim Biogeographic Regionalisation for Australia, interim Australian bioregion. The Coral Sea extends down t ...

and at the

Cocos (Keeling) Islands The Cocos (Keeling) Islands (), officially the Territory of Cocos (Keeling) Islands (; ), are an Australian external territory in the Indian Ocean, comprising a small archipelago approximately midway between Australia and Sri Lanka and rel ...

. It has been recorded once in the Mediterranean Sea off Libya but how this specimen reached there is uncertain. At remote islands such as Rapa, Pitcairn and the

Line Islands The Line Islands, Teraina Islands or Equatorial Islands () are a chain of 11 atolls (with partly or fully enclosed lagoons, except Vostok and Jarvis) and coral islands (with a surrounding reef) in the central Pacific Ocean, south of the Hawa ...

this species may be the only rabbitfish present. It occurs at depths down to in lagoons, on reefs, and in seaweed and seagrass beds.

Biology

The streamlined spinefoot is normally found in large, fast swimming schools on the water column clear of the seabed, every now and again they all dive down to the substrare to feed. Juveniles and adults may be encountered in small schools of 2–100 individuals near coral reefs, usually in the surge zone on the edge of the reef. Juveniles inhabit the water close to the surface in dense schools as far as several kilometres offshore, moving on to reef flats just before metamorphosis. The streamlined spinefoot has a diet made up of red and green

macroalgae Seaweed, or macroalgae, refers to thousands of species of Macroscopic scale, macroscopic, Multicellular organism, multicellular, ocean, marine algae. The term includes some types of ''Rhodophyta'' (red), ''Brown algae, Phaeophyta'' (brown) and ...

and it is one of the few herbivorous fishes that is able to eat the chemically rich macroalgae '' Chlorodesmis fastigata'', however, this algae may only be eaten opportunistically and is likely a minor part of the total diet. They have spines which can inject venom into an attacker. Unusually for a rabbitfish, the streamlined spinefoot is a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

spawner and has a relatively long

larval A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

stage and a unique prejuvenile stage. These long developmental stages allow it to disperse widely and makes the species less vulnerable than its congeners to overfishing.

Fisheries

Streamlined spinefoot are frequently recorded in markets in parts of their range, both as juveniles and adults. The pre-juveniles are taken as they migrate to reef flat areas in a brief but important part of local fisheries, e.g. in Guam. They are consumed fresh, pickled in brine, or made into fish paste.

References

External links

* {{Taxonbar, from=Q1044087 Siganidae Fish of the Indian Ocean Fish of the Pacific Ocean Fish described in 1825 Taxa named by Jean René Constant Quoy Taxa named by Joseph Paul Gaimard