''Ranina ranina'', also known as the Huỳnh Đế crab, (red) frog crab or spanner crab, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

found throughout

tropical The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...

and

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones immediately to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Ge ...

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

s. It is often fished for its meat.

Description

It may grow up to long, and may weigh up to . The

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

is wider at the front, reddish brown in color, with ten white spots. ''Ranina ranina'' is mainly

nocturnal Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

, and remains buried in the

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

during the day. ''Ranina ranina'' is easily distinguished from other crab species in its habitat due to its red carapace and elongated midsection.

Distribution and ecology

Spanner crabs inhabit coastal waters along the east coast of Australia, from Yeppoon in Queensland to the North coast of New South Wales. There is also a population to the north of Perth in Western Australia. ''Ranina ranina'' is abundant in the coastal waters of south-western Mindanao, Philippines. These crabs are also found in the eastern coast of Africa, across the Indian Ocean to Indonesia, Japan and Hawaii and Vietnam.Juliana C. Baylon & Oliver D. Tito (2012) “Natural diet and feeding habits of the red frog crab (''Ranina ranina'') from southwestern Mindanao, Philippines” Philip. Agric. Scientist Vol. 95 No. 4, 391–398. ''Ranina ranina'' inhabits depths of on sandy-smooth substrata in which they bury themselves from where they attack small bottom-dwelling fish.Sydney Fish Market, “Species information: Spanner Crab” (2013) www.sydneyfishmarket.com When waiting for prey, ''Ranina ranina'' will cover itself with sand, but leave its eye and mouthparts sticking out to help detect its food. Offshore areas within this range in a subtropical or tropical environment serves as a habitat for ''Ranina ranina'', but they must have ample sand for ''Ranina ranina'' to flourish, as covering themselves in sand is instrumental in their method of catching prey. The Ranina Ranina crab is a popular species of crab that gets fished, in Australia, 96% of the female crab doesn’t get fished. In one location during spawning season, the decrease in females being hunted doesn’t apply. Meaning that the specific area of Tallows Beach is the focus of spawning migration.

Fishery

The species is commercially exploited over much of its

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

, but the largest fishery is in Australia, where the annual commercial catch an estimated at .Queensland Fisheries (2010) “Stock Status of Queensland's Fisheries Resources 2009-10” Queensland Australia: Queensland Department of Employment, Economic Development and Innovation. 65 In

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 ...

, only adults above

length may be landed. In the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

in 2008, prices for ''Ranina ranina'' were around 200–300 pesos per

kilogram The kilogram (also spelled kilogramme) is the base unit of mass in the International System of Units (SI), equal to one thousand grams. It has the unit symbol kg. The word "kilogram" is formed from the combination of the metric prefix kilo- (m ...

. ''Ranina ranina'' populations have been surveyed to avoid

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

and are currently stable.J. McGilvray, I. Brown, E. Jebreen & D. Smallwood (2006) Fisheries Long Term Monitoring Program Summary of spanner crab (''Ranina ranina'') survey results: 2000-2005. Department of Primary Industries and Fisheries, Queensland, QI06095, Brisbane, Australia. Although ''Ranina ranina'' is a target of commercial fishing operations, little is known about the species' biology, population dynamics and ecology. Attempts have been made to grow ''Ranina ranina'' in captivity, but have so far been met with little success.

Culinary use

''Ranina ranina'' is a regional specialty in some regions of the Philippines where it is known as ''

curacha ''Ranina ranina'', also known as the Huỳnh Đế crab, (red) frog crab or spanner crab, is a species of crab found throughout tropical and subtropical habitats. It is often fished for its meat. Description It may grow up to long, and may wei ...

''. It is generally eaten steamed as ''

halabos ''Halabós'' is a Filipino cooking process consisting of fresh shrimp, crab, or other crustaceans cooked in water and salt. Modern versions of the dish commonly add spices and use carbonated lemon drinks instead of water for a sweeter sauce. ...

'', or cooked in coconut milk as ''

ginataan ''Ginataan'' (pronounced: ), alternatively spelled ''guinataan'', is a Filipino language, Filipino term which refers to food cooked with ''gatâ'' (coconut milk). Literally translated, ''ginataan'' means "done with coconut milk". Due to the gene ...

''. A notable variant of the latter is the ''

curacha Alavar ''Curacha Alavar'', sometimes referred to as ''curacha con salsa Alavar'' ("Curacha with Alavar sauce") in Chavacano a Spanish-based creole language, is a Filipino dish made from spanner crabs (''curacha''), garlic, ginger, salt, and Alavar sau ...

'' of

Zamboanga City Zamboanga City, officially the City of Zamboanga (; ; Subanen languages, Subanen: ''Bagbenwa Sembwangan''; Sama–Bajaw languages, Sama: ''Lungsud Samboangan''; ; ; ) is a Cities of the Philippines#Legal classification, highly urbanized city i ...

. In Vietnam the species is named as "Huỳnh Đế crab", literally means "emperor crab". The names refer to the fact that ''R. ranina'' is one of the favorite high-ranked cuisine of historical Vietnamese monarchs. It is the delicacy harvested in the provinces Bình Định and

Quảng Ngãi Quảng Ngãi () is a city in central Vietnam. It serves as the capital city of Quảng Ngãi Province. Quảng Ngãi City borders Tư Nghĩa District to the South and West, Sơn Tịnh District to the Northwest and Bình Sơn District to the ...

, and is hailed "monarch of all the crab".

References

External links

* * {{Taxonbar, from=Q2219121 Crabs Marine fauna of Eastern Australia Edible crustaceans Commercial crustaceans Crustaceans described in 1758 Taxa named by Carl Linnaeus