Food and Agriculture Organization of the United Nations Fisheries and for a world without hunger Aquaculture Department

Species Fact Sheets declivis (Jenyns, 1841)

Trachurus declivis: (click for more) Trachurus declivis: (click for more)

Synonyms Caranx declivis Jenyns, 1841: 68 (original description).

FAO Names En - Greenback horse , Fr - Chinchard dos vert, Sp - Jurel verde. 3Alpha Code: HMG Taxonomic Code: 1702300415

Diagnostic Features Body elongate, fairly compressed. Head large; posterior end of upper jaw reaching anterior margin of eye; lower jaw projected. Maxilla large, wide, not covered by lacrymal. Adipose eyelid well developed. Small nostrils closely situated each other, anterior nostril oval and posterior nostril crescent. A distinct notch on posterior margin of opercle. Dorsal accessory lateral line terminating below soft dorsal rays 15-17. Gillrakers, including rudiments, 36-44 on lower limb of first gill arch; total gillrakers 50-57. First dorsal fin with 8 spines and I + 29-34. Anal fin with I + 25-31 preceded by 2 strong spines. Pectoral fin with 18-21 rays. Pelvic fin (I,5) moderate in size, originating below end of pectoral fin base. Scales in curved lateral line 35-42. expanded dorsolaterally and scute-like, in straight lateral line 38-45 scutes; total scales and scutes 74-84.

Geographical Distribution

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Southern Pacific. Princess Royal Harbor, King George Sound, Western Australia and New Zealand waters.

Habitat and Biology Generally found at less than 300 m water depthwith temperature less than 16° C. Commonly found on the bottom, in midwater and occasionally at the surface.Feeding primarily on crustaceans (copepods), shrimps, but also small fishes and squid.

Size To about 50 cm total length; common 35 cm.

Interest to Fisheries Greenback horse mackerel are an important commercial species with the main fishing grounds off the west coast of the North of New Zealand. Caught commercially with trawls, purse seines, traps and on line gear. The total catch reported for this species to FAO for 1999 was 15 529 t. The countries with the largest catches were Ukraine (15 306 t) and Russian Federation (223 t).

FAO Fisheries and Aquaculture Department Global Capture Production for species (tonnes) Source: FAO FishStat 150k

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Trachurus declivis

Local Names English : Australian jack mackerel , Common jack mackerel , Greenback scad , Horse mackerel , Jack mackerel , Tasmanian jack mackerel . Polish : Ostrobok australijski .

Remarks The Peruvian jack horse mackerel or Southern jack mackerel (Trachurus murphyi ) is almost identical in appearance to the Greenback horse mackerel (T. declivis ). The best characteristics for differentiating betwen the two species are total number of gillrakers (51-65 in T. murphyi and 50-57 in T. declivis ) and the number of scales and scutes in the lateral line (89-113 in T. murphyi and 74-84 in T. declivis ) and their relative heigths.

Bibliography Ayling, T. & G. J. Cox. - 1982Collins Guide to the Sea Fishes of New Zealand. William Collins Publish. Ltd., Auckland, Sydney, London: 343 pp. Ben Salem, M. - 1988 Taxinomie numérique des espèces du genre Trachurus Froese, R. and D. Pauly. Editors. 2003. FishBase. World Wide Web electronic publication. www.fishbase.org Pullen, G., H. Williams & P. Last. - 1989Sout American fish found off Tasmania. Australian Fisheries (Research briefs), june, 1989: 35. Rafinesque, 1810 (Poissons, Téléostéens, ). Cybium, 12 (1): 45-58.

FAO Fisheries and Aquaculture Department