The red handfish (''Thymichthys politus'', formerly ''Brachionichthys politus'') is a species of

handfish Handfish are any anglerfish within the family Brachionichthyidae, a group which comprises five genera and 14 extant species. These benthic marine fish are unusual in the way they propel themselves by walking on the sea floor rather than swimmi ...

in the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Thymichthys ''Thymichthys'' is a genus in the handfish family Brachionichthyidae. Like other handfishes, they move by means of walking on their pectoral fins, which resemble hands. ''Thymichthys'' is distinguished by its wart-like protuberances, strongly d ...

,'' found in

Frederick Henry Bay Frederick Henry Bay is a body of water in the southeast of Tasmania, Australia. It is located to the east of the South Arm Peninsula, and west of the Tasman Peninsula. Towns on the coast of the bay include Lauderdale, Seven Mile Beach, Dodges ...

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

Description

The red handfish is distinguished by its small, flattened wart-like protuberances that cover its body and red colouration. Two colour morphs exist, a bright red morph with red colour on both body and fins, with a black line separating the white fin edges and a mottled morph with pink body covered in many red patches, with translucent pink fins expressing some bright red patches. They

measure Measure may refer to: * Measurement, the assignment of a number to a characteristic of an object or event Law * Ballot measure, proposed legislation in the United States * Church of England Measure, legislation of the Church of England * Mea ...

an average standard length of 61.4 mm (2.4 in) and an average total length of 80.1 mm (3.2 in). Like other handfishes, they have large developed

pectoral fins 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 se ...

, which they use to walk along the sea floor.

Distribution

Historically, the species was found in multiple subpopulations in Tasmania, including Port Arthur,

Fortescue Bay Fortescue Bay or Baje Dolomien is a bay in southeast Tasmania, Australia. It is located east of Port Arthur, Tasmania, and makes up part of Tasman National Park. Within the bay are two smaller nested bays, Canoe Bay and Bivouac Bay. History T ...

, the

Actaeon Island The Actaeon Island, part of the Actaeon Island Group, is a dolerite island and game reserve located at the southern entrance to the D'Entrecasteaux Channel between Bruny Island and the mainland, that lies close to the south-eastern coast of Tas ...

D'Entrecasteaux Channel The D'Entrecasteaux Channel is a body of water located between Bruny Island and the south-east of the mainland of Tasmania, Australia. The channel is the mouth for the estuaries of the Derwent and the Huon Rivers and empties into the Tasman S ...

, and the

Forestier Peninsula The Forestier Peninsula is a peninsula located in south-east Tasmania, Australia, approximately by the Arthur Highway, south-east of Hobart. The peninsula is connected to mainland Tasmania at East Bay Neck, near the town of at its northern e ...

. Currently, the species has been found only on 2 small reefs in Frederick Henry Bay. These species typically reside in reef sand junctions, where there is an abundance of sand and rocks. These reefs measure a circular area of no more than 75 meters and 50 meters in diameter. It is found at depth ranges from 1 m up to 20 m.

Threats and conservation

General threats to red handfish include small, very fragmented populations and local increases in density of native purple urchins. Native purple urchins overgraze the seaweed habitat required for shelter and spawning for the red handfish. Summer observations of low seaweed on urchin barrens suggest that loss of seaweed habitat might represent a key threat to long term viability of the population In addition, the close vicinity of urban development increases the risk of nutrient runoff, pollution, siltation, and turbidity. This results in habitat degradation through the ruin of the red handfish's preferred seaweed habitat. The red handfish is classed as Critically Endangered under the Australian ''

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 cultu ...

'' (EPBC Act) and by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

, 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 th ...

''. Red handfish may face severe pressure due to direct environmental consequences of warming coastal waters, including potential implications on reproduction, egg development, feeding, and escape reaction, which are currently unknown.

Footnotes

References

* Graham J. Edgar. (2017). New opportunities for conservation of handfishes (Family Brachionichthyidae) and other inconspicuous and threatened marine species through citizen science. ScienceDirect. 174-182. . * Jemima, Smith. (2020). Conservation challenges for the most threatened family of marine bony fishes (handfishes: Brachionichthyidae). ScienceDirect. * Lynch, Tim. (2015). Diver towed GPS to estimate densities of a critically endangered fish. ScienceDirect. These sources are from the science citation index. Specifically, they were found through the University of Illinois at Chicago database. {{Taxonbar

red handfish The red handfish (''Thymichthys politus'', formerly ''Brachionichthys politus'') is a species of handfish in the genus ''Thymichthys,'' found in Frederick Henry Bay, Tasmania. Description The red handfish is distinguished by its small, flatten ...

Endemic fauna of Tasmania Marine fish of Tasmania