Greenback Horse Mackerel

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.

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

To about 50 cm total length; common 35 cm.

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.

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).

Adults are elongate and slightly compressed, and have a primary lateral line with 71-89 scutes, and a secondary lateral line reaching to below dorsal-fin rays 7-9 (Ref. 33616).

Irona Infestation. Parasitic infestations (protozoa, worms, etc.)

Codonophilus Infestation. Parasitic infestations (protozoa, worms, etc.)

Eggs and sperm are released amongst schooling fish, possibly deep in the water column near the edge of the continental shelf. Eggs are distributed between the surface and the thermocline and larvae are carried inshore by currents.

Dorsal spines (total): 9; Dorsal soft rays (total): 29 - 35; Analspines: 3; Analsoft rays: 24 - 29; Vertebrae: 24

Commonly found near the bottom, in midwater and occasionally at the surface (Ref. 9258) in continental shelf waters (Ref. 27930). They form pelagic schools for most of the year but may move close to the sea bed during winter (Ref. 27931). Generally found at less than 300 m water depth with temperature less than 16° C (Ref. 9072). Juveniles inhabit coastal and estuarine waters although they may sometimes be found offshore (Ref. 27930). Feed mostly during the day mainly on krill and other planktonic crustaceans, light fish (Sternoptychidae) and lantern fish (Myctophidae) at the edge of the continental shelf (Ref. 27933).Seasonal patterns in the presence of surface schooling jack mackerel are thought to be a response to water temperature rather than evidence of migration, as surface schools are not generally found in water temperature above 17°C (Ref. 27933). Jack mackerel form schools of similar sized fish and there is evidence from demersal trawl surveys that the size of fish tends to increase with increasing depth of water (Ref. 5868).

Adults are commonly found near the bottom, in midwater and occasionally at the surface (Ref. 9258) in continental shelf waters (Ref. 27930). They form pelagic schools for most of the year but may move close to the sea bed during winter (Ref. 27931). Generally found at less than 300 m water depth with temperature less than 16° C (Ref. 9072). Juveniles inhabit coastal and estuarine waters although they may sometimes be found offshore (Ref. 27930). Adults feed mostly during the day mainly on krill and other planktonic crustaceans, light fish (Sternoptychidae) and lantern fish (Myctophidae) at the edge of the continental shelf (Ref. 27933).

fisheries: highly commercial; gamefish: yes; bait: usually; price category: very high; price reliability: reliable: based on ex-vessel price for this species

The greenback horse mackerel or greenback scad (Trachurus declivis) is a species of jack in the family Carangidae, found around western and southern Australia, and around New Zealand, from the surface to depths of 460 m. Its length is up to 64 cm.

Its common name derives from the legend that other smaller species of fish could ride on its back over great distances. It is an important commercial fish and sports fishing quarry although it has strong tasting flesh.