The spotted handfish (''Brachionichthys hirsutus'') is a rare Australian fish in the handfish family, Brachionichthyidae, classified as critically endangered on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

2020. It has a highly restricted range, being found only in the

estuary An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environm ...

of Derwent River,

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

, and nearby areas, with the main threat to its existence being an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species adv ...

, the

Northern Pacific seastar ''Asterias amurensis'', also known as the Northern Pacific seastar and Japanese common starfish, is a seastar found in shallow seas and estuaries, native to the coasts of northern China, Korea, far eastern Russia, Japan, Alaska, the Aleutian Isla ...

(''Asterias amurensis''). The spotted handfish is an unusual fish, in that it has highly adapted

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s, which appear like hands (hence the name) and allow it to walk on the sea floor.

Description

The spotted handfish is a rare species in the handfish

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

, Brachionichthyidae. The handfishes are a unique, Australian family of

anglerfish The anglerfish are fish of the teleost order Lophiiformes (). They are bony fish named for their characteristic mode of predation, in which a modified luminescent fin ray (the esca or illicium) acts as a lure for other fish. The luminescence ...

, the most speciose of the few marine fish families endemic to Australia. Handfish are unusual, small (up to in length), slow-moving, fishes that prefer to 'walk' rather than swim. Their pectoral fins are leg-like with extremities resemblant of a sort-of hand (hence their common name). The females are believed to reach sexual maturity after two to three years at lengths of to .

Habitat

The spotted handfish It is a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

fish usually found at depths of to , with overall sightings varying from a minimum of to a maximum of deep. It chooses habitats based on the microhabitat features. It tends to prefer complex habitats with features such as depressions and ripple formations filled with shells to avoid predators.

Reproduction

CSIRO ScienceImage 11186 The Endangered Spotted Handfish

The species spawns sometime during September and October. Females lay a number of eggs varying from 80 to 250 eggs on a variety of vertical objects, including

sea grass Seagrasses are the only flowering plants which grow in marine environments. There are about 60 species of fully marine seagrasses which belong to four families ( Posidoniaceae, Zosteraceae, Hydrocharitaceae and Cymodoceaceae), all in the ...

es,

sponges Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

, macrophytic algae, polychaete worm tubes, and stalked ascidians. The eggs are large in diameter measuring approximately 3–4 mm. Handfish have a short

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...

larval period; their eggs hatch after 7–8 weeks as fully formed juveniles (6–7 mm SL).

Diet

Little is known regarding their diet, but they have been reported to prey on small

shellfish Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater env ...

, shrimp, and

polychaete Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are ...

worms in the wild. When captive in aquaria, spotted handfish eat

mysid shrimp Mysida is an order of small, shrimp-like crustaceans in the malacostracan superorder Peracarida. Their common name opossum shrimps stems from the presence of a brood pouch or "marsupium" in females. The fact that the larvae are reared in this ...

, amphipods, and small live fish. Newly hatched handfish have been observed to do quite well on a diet of small amphipods. Brachionichthys hirsutus RLS

Conservation

In 1996, the spotted handfish was the first marine fish to be listed as critically endangered in the

, and is still classified as such (, last assessed 2018). It has the same classification under Australia's ''

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...

'' (EPBC Act), and as Endangered under Tasmania's ''

Threatened Species Protection Act 1995 The ''Threatened Species Protection Act 1995'' (TSP Act), is an act of the Parliament of Tasmania that provides the statute relating to conservation of flora and fauna. Its long title is An Act to provide for the protection and management of t ...

''.

Attribution 4.0 International (CC BY 4.0)
licence. All handfish species are protected under the Tasmanian ''Living Marine Resources Management Act 1995'', which prohibits their collection in State waters without a permit. CC-BY icon

Attribution 3.0 Australia (CC BY 3.0 AU)
licence. The most urgent matter concerning the survival of the species is to address the threat posed by the presence of an introduced species of seastar, the

(''Asterias amurensis''), which prey on not only the fish eggs, but also on the sea squirts ( ascidians) that help to form the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

that the fish spawn on. Since the seastar, native to Japanese waters, was established in the Derwent River and

in the 1980s, efforts have been made to control its spread in Australia.

References

General source

External links

* * (1999) {{DEFAULTSORT:handfish, spotted spotted handfish Endemic fauna of Tasmania spotted handfish