Alepes

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Alepes
Fossil range: Miocene to Present[1]
Razorbelly scad
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Suborder: Percoidei
Superfamily: Percoidea
Family: Carangidae
Genus: Alepes
(Swainson, 1839)
Type species
Trachinus melanoptera,
Swainson, 1839
Species
Synonyms
  • Trachinus Swainson, 1839

Alepes is a genus containing five extant species of tropical marine fishes in the jack family, Carangidae. They are commonly known as scads, a term applied to many genera of carangid fishes. Their body form, however, differs from these other scads by being much more ovate in shape, more similar to the larger jacks taken as game fish, although scads are generally much smaller. They are found in coastal waters throughout the Indo-West Pacific region.

Contents

[edit] Taxonomy and phylogeny

Alepes is a genus containing five extant and one extinct species. It is part of the jack family, Carangidae, a group of perciform fish in the suborder Percoidei. Recent phylogenetic studies using molecular information have placed Alepes in the subfamily Caranginae (or the tribe Carangini).[2] The most comprehensive study suggests the genus is basal to all other 'scads' and 'horse mackerels' of the genera Trachurus, Decapterus, and Selar, whilst still being closely affiliated with larger members of Caranginae such as Caranx.[3]

Alepes was first created in 1839 by the English naturalist William Swainson, after he initially proposed it to be a subgenus of Trachinus, which he had created to accommodate Trachinus melanoptera, a species he had just described.[4] Trachinus was invalid, however, as it was already in use for a genus of weevers. This makes A. melanoptera the type species of the genus. The other species currently placed in Alepes were not directly classified in the genus, but were transferred from other, often distantly related genera. Many of these species have numerous junior synonyms.[5] "Alepes" comes from the Greek word alepis, 'without scales'.[6]

A single species has been identified from the fossil record; Alepes pin, described from the Lower Miocene in eastern Crimean Oblast. This area was once part of the Indian Ocean which extended well into Europe at the time.[7]

[edit] Species

Smallmouth scad, Alepes apercna
Smallmouth scad, Alepes apercna

[edit] Biology

The species in Alepes are all relatively small fish, with the largest, A. vari, growing to 56 centimetres (22 in).[6] The other species are much more often encountered at sizes below 20 centimetres (8 in).[8] They have strongly compressed ovate to oblong shaped bodies, with fin arrangements much like the rest of the Carangidae. They have two dorsal fins, the first consisting of weak spines and the second of a single spine followed by a number of soft rays. The anal fin has two detached spines anterior to the main section which consists of one spine and a number of soft rays.[8] Their lateral lines have a moderate to strong anterior curve, with scutes present on the straight section of the lateral line. They are all a blue-green-grey above, fading to silvery white below. Only one, A. kleinni has bands or markings.[9]

The fish in Alepes are all predators, taking a range of crustaceans including copepods, decapods, prawns and shrimp, as well as small fish.[8] At least one species shows a change in feeding intensity over the period of a year.[10] The reproduction of most species is unstudied, except for A. kleinii. This species spawns on a single event over a period of a few months, releasing small transparent, pelagic eggs.[11] Natural spawning behavior in the genus is unknown.

[edit] Distribution and habitat

The members of Alepes are all distributed in the tropical to subtropical regions of the Indo-West Pacific region. Their ranges overlap along the Indian, Asian and Indonesian coastlines, although some are distributed as far south as South Africa and northern Australia, while others extend as far north as Japan.[6] Two species, A. djedaba and A. kleinii are known to inhabit the Red Sea, and have passed into the Mediterranean Sea through the Suez canal as part of the Lessepsian migration.[12] They are all coastal species, not found in the open ocean.

[edit] Relationship to humans

The species of Alepes are not of major commercial interest, although Alepes kleinii appears to be taken in substantial enough numbers in India to warrant extensive research. They are taken by a variety of fishing methods including hook and line, trawls and a variety of netting methods.[8] Their flesh is of good quality, and some regions regard various species as high quality and market them fresh, or dried and salted.[13] They are of no interest to recreational fishermen, although occasionally taken as bait or bycatch.

[edit] References

  1. ^ Sepkoski, Jack (2002). "A compendium of fossil marine animal genera". Bulletins of American Paleontology 364: 560. 
  2. ^ Zhu, Shi-Hua; Zheng, Wen-Juan; Zou, Ji-Xing; Yang, Ying-Chun; Shen, Xi-Quan (2007). "Molecular phylogenetic relationship of Carangidae based on the sequences of complete mitochondrial cytochrome b gene". Acta Zoologica Sinica 53 (4): 641–650. 
  3. ^ Reed, David L.; Kent E. Carpenter and Martin J. deGravelle (2002). "Molecular systematics of the Jacks (Perciformes: Carangidae) based on mitochondrial cytochrome b sequences using parsimony, likelihood, and Bayesian approaches". Molecular Phylogenetics and Evolution 23 (3): 513–524. USA: Elsevier Science. doi:10.1016/S1055-7903(02)00036-2. 
  4. ^ Swainson, W. (1839). The natural history and classification of fishes, amphibians, & reptiles, or monocardian animals. London: Spottiswoode & Co, 176, 248. 
  5. ^ Lin, Pai-Lei; Shao, Kwang-Tsao (1999). "A Review of the Carangid Fishes (Family Carangidae) From Taiwan with Descriptions of Four New Records". Zoological Studies 38 (1): 33–68. 
  6. ^ a b c "Alepes". FishBase. Ed. Ranier Froese and Daniel Pauly. October 2007 version. N.p.: FishBase, 2007.
  7. ^ Bannikov, A.F. (1985). "A Find of the Genus Alepes: Teleoisti in the Miocene Crimean Oblast, Ukrainian-SSR USSR". Paleontologicheskii Zhurnal 1 (1): 101–107. ISSN 0031-031X. 
  8. ^ a b c d Carpenter, Kent E.; Volker H. Niem (eds.) (2001). FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 5. Bony fishes part 3 (Menidae to Pomacentridae). Rome: FAO, 2684. ISBN 92-5-104587-9. 
  9. ^ Randall, John E. (1995). Coastal Fishes of Oman. Honolulu: University of Hawaii Press, 183. ISBN 0-8248-1808-3. 
  10. ^ Kalita, Binod; Jayabalan, N. (2000). "Food and feeding habits of the golden scad Caranx kalla (Cuv. & Val.) along Mangalore coast". Environment and Ecology 18 (4): 869–873. ISSN 0970-0420. 
  11. ^ Venkataramani, V.K.; Natarajan, R. (1984). "Breeding biology of carangid fishes Carangoides malabaricus (Bloch and Schn.) and Alepes kalla (Cuv. and Val.) along Porto Novo Coast". Indian Journal of Marine Sciences 13 (1): 14–18. ISSN 0379-5136. 
  12. ^ Adam, B.T. (1966). "Red Sea Fishes Recently Found in the Mediterranean". Copeia 1966 (2): 254–275. doi:10.2307/1441133. 
  13. ^ Davidson, Alan (2004). Seafood of South-East Asia: A Comprehensive Guide with Recipes. Ten Speed Press, 63. ISBN 1-58008-452-4. 

[edit] External links