''Rhabdosargus globiceps'', the white stumpnose or go-home fish, 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 ...

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 ...

Sparidae Sparidae is a family of ray-finned fishes belonging to the order Spariformes, the seabreams and porgies, although they were traditionally classified in the order Perciformes. The over 150 species are found in shallow and deep marine waters in t ...

, which includes the seabreams and porgies. This fish is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to the waters off

Southern Africa Southern Africa is the southernmost region of Africa. No definition is agreed upon, but some groupings include the United Nations geoscheme for Africa, United Nations geoscheme, the intergovernmental Southern African Development Community, and ...

Taxonomy

''Rhabdosargus globiceps'' was first formally described in 1830 as ''Chrysophrys globiceps'' by the French

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Achille Valenciennes Achille Valenciennes (9 August 1794 – 13 April 1865) was a French zoology, zoologist. Valenciennes was born in Paris, and studied under Georges Cuvier. His study of parasitic worms in humans made an important contribution to the study of parasi ...

with its type locality given as the

Cape of Good Hope The Cape of Good Hope ( ) is a rocky headland on the Atlantic Ocean, Atlantic coast of the Cape Peninsula in South Africa. A List of common misconceptions#Geography, common misconception is that the Cape of Good Hope is the southern tip of Afri ...

in South Africa. The genus ''Rhabdosargus'' is placed in the family Sparidae within the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Spariformes Spariformes is an order of ray-finned fishes consisting of six families within the series Percomorpha. Taxonomy Spariformes was first used as a taxonomic term in 1860 by the Dutch physician, herpetologist and ichthyologist Pieter Bleeker. Trad ...

by the 5th edition of ''

Fishes of the World ''Fishes of the World'' is a standard reference for the systematics of fishes. It was first written in 1976 by the American ichthyologist Joseph S. Nelson (1937–2011). Now in its fifth edition (2016), the work is a comprehensive overview of t ...

''. Some authorities classify this genus in the subfamily Sparinae, but the 5th edition of Fishes of the World does not recognise subfamilies within the Sparidae.

Etymology

''Rhabdosargus globiceps'' has the generic name ''Rhabdosargus'' which is a combination of ''rhabdos'', meaning "stick" or "rod", an allusion to the yellow abdominal band of ''Sargus auriventris'', the type species of the genus. The second part is ''Sargos'', a name used for Sparid fish in

ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

at least as long ago as

Aristotle Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...

but in this case is a reference to ''Sargus'' as a

synonym A synonym is a word, morpheme, or phrase that means precisely or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are a ...

of ''

Diplodus ''Diplodus'' is a genus of marine ray-finned fish belonging the family Sparidae, which includes the seabreams and porgies. These fishes are found in the Atlantic Ocean, the Mediterranean Sea and the western Indian Ocean. Taxonomy ''Diplodus'' wa ...

''. 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 ...

, ''globiceps'', combines ''globus'', meaning "sphere", and ''ceps'', meaning "head", an allusion to the protuberance between the yes of this species.

Description

''Rhabdosargus globiceps'' has 11 spines and between 11 and 13 spines supporting 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 ...

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 ...

is supported by 3 spines and 10 or 11 soft rays. The body is compressed and moderately deep, its depth fitting into its

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 ...

between 2.2 and 2.4 times. The dorsal profile of the head is quite steep, with a bulge in front of the eyes, and then smoothly rounded to the origin of the dorsal fin. The flange on the

preoperculum This glossary of ichthyology is a list of definitions of terms and concepts used in ichthyology, the study of fishes. A B C ...

is scaleless. The overall colour of the body is silvery with 5 or 6 dark, vertical bars along the back. with dusky fins. This species has a maximum published

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.

Distribution and habitat

''Rhabdosargus globiceps'' is endemic to Southern Africa where it is found in the southeastern Atlantic from Angola south to the

Western Cape The Western Cape ( ; , ) is a provinces of South Africa, province of South Africa, situated on the south-western coast of the country. It is the List of South African provinces by area, fourth largest of the nine provinces with an area of , an ...

east into the southwestern Indian Ocean where it reaches as far north as

KwaZulu-Natal KwaZulu-Natal (, also referred to as KZN) is a Provinces of South Africa, province of South Africa that was created in 1994 when the government merged the Zulu people, Zulu bantustan of KwaZulu ("Place of the Zulu" in Zulu language, Zulu) and ...

. The white stumpnose is found over sandy substrates, the juveniles are found in estuaries while the adults can be found as deep as .

Biology

''Rhabdosargus globiceps'' are found on shallow reefs down to depths of in the summer while in the winter, at

Agulhas Bank The Agulhas Bank (, from Portuguese for Cape Agulhas, ''Cabo das Agulhas'', "Cape of Needles") is a broad, shallow part of the southern African continental shelf which extends up to south of Cape Agulhas before falling steeply to the abyssal pla ...

they are found in waters as deep as on reefs and loose sediments. The juvenile fish are common in inshore waters of estuaries and bays where they may be found in the surf zone, in seagrass beds and in coastal lagoons. There is a subpopulation of the white stumpnose in the Langebaan Lagoon on the Atlantic coast of the Western Cape and these fishes are found in tidal channels and over sandy substrates. The adults in this subpopulation disperse offshore during the winter and in summer they concentrate in areas of less than depth, responding to oceanographic conditions of the summer. Tagging studies have shown that this population is rather mobile, spending midwinter in

Saldanha Bay Saldanha Bay () is a natural harbour on the south-western coast of South Africa. The town that developed on the northern shore of the bay, also called Saldanha, Western Cape, Saldanha, was incorporated with five other towns into the Saldanha Bay ...

and the rest of the year in the Langebaan Lagoon where they are rather sedentary but will commute daily to preferred sites. This fish is predatory, feeding largely on crustaceans and molluscs with the larger adults being able to crush clams, mussels and snails while the juveniles feed on

amphipod Amphipoda () is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphipod species cur ...

isopods Isopoda is an Order (biology), order of crustaceans. Members of this group are called isopods and include both Aquatic animal, aquatic species and Terrestrial animal, terrestrial species such as woodlice. All have rigid, segmented exoskeletons ...

ostracods Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant) have been identified,Brandão, S.N.; Antonietto, L.S; Nery, D.G.; Santos, S.G.; Karano ...

and filamentous algae. The longest this fish is known to have lived is 21 years. The white stumpnose is a rudimentary hermaphrodite, with less than 1% of individuals hiving both

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

and

testes A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of androgens, primarily testosterone. The ...

. They

spawn Spawn or spawning may refer to: * Spawning, the eggs and sperm of aquatic animals Arts, entertainment and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** ''Spawn: Armageddon' ...

between September and March and sexual maturity occurs at around 1.5 to 3 years old and fork lengths of to for males and for females.

Fisheries and conservation

''Rhabdosargus globiceps'' is an economically important species, large numbers are caught by net fishers and anglers in the Cape of Good Hope region, often catching the fish inshore at night. It is also a sought-after sporting fish for recreational fishers using light tackle. It is taken as bycatch by trawlers and beach seine fishers. In some areas where it was caught by beach seiners the stock has collapsed. As the population of this species has declined by more than 30% over 3 generations the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

has classified this species as Vulnerable. In South Africa minimum sizes and bag limits have been imposed and there are

Marine protected area A marine protected area (MPA) is a protected area of the world's seas, oceans, estuaries or in the US, the Great Lakes. These marine areas can come in many forms ranging from wildlife refuges to research facilities. MPAs restrict human activity ...

s which protect this fish, including the

West Coast National Park The West Coast National Park lies north of Cape Town in the Western Cape province of South Africa. The park is found inside of the Cape West Coast Biosphere Reserve, part of the UNESCO Man and the Biosphere Programme. It is bordered by the Atl ...

which contains Langebaan Lagoon.

References

Sources

* ''Sea Fishes of Southern Africa''. Rudy van der Elst & Dennis King. 2006. ISBN 978-1-77007-345-6. * ''Gids tot die kusgebiede van Suid-Afrika''. Jacana Media. 2007. ISBN 978-1-77009-215-0. * ''Coastal Fishes of Southern Africa''. Phil & Elaine Heemstra. 2004. ISBN 1-920033-01-7

External links

* http://www.fishbase.org/summary/Rhabdosargus-globiceps.html {{Taxonbar, from1=Q2054332 globiceps