Seriola dumerili commonly known as amberjack, is a fish belonging to the order Caragniformes, and within this to the family Carangidae. It is a species that lives in open water but close to the coast, and can be found at depths of up to 300 meters. Generally juveniles tend to be in shallow waters (up to 10 meters) and associate with floating Sargassum algae or drifting objects, and it is the adults that will be more frequently sighted between 20 and 70 meters depth. The geographical distribution of Seriola dumerili includes the waters of the Mediterranean Sea, the Atlantic Ocean (from South Africa to Great Britain, and from Nova Scotia to Brazil) and in the Pacific (Australia, China, Japan and Hawaii).
Seriola dumerili is a species that can reach very considerable sizes. There are records of specimens up to 188 cm in total length and up to 80.6 kg in weight. Although this is true, it is normal to find specimens of 70-110 cm. It is a very fast and agile fish, with an elongated body, moderately low in height and slightly compressed laterally. The dorsal profile of the body is noticeably more convex than the ventral edge of the body. As for the head, it is slightly rounded, and we find a mouth that extends to about the vertical line of the middle of the eyes.
As for the fins of Seriola dumerili, it has two dorsal fins. The first one is short and consists of 7 spiny rays. Generally the first and last spiny ray of this first dorsal fin are in adult specimens embedded in the body of the individual and can go unnoticed. The second dorsal fin, much longer than the first, has one spiny ray followed by between 29 and 34 soft rays. If we move to the anal fin, we find that it is formed by two small isolated spines, followed by 1 spiny ray and 18 to 22 soft rays. The soft region of the anal fin is shorter in length than the soft region of the second dorsal fin, and the beginning of the anal fin is offset in the horizontal with respect to the beginning of the second dorsal fin. As for the caudal fin, the upper lobe is slightly smaller than the lower one.
The coloration of the body of the specimens of Seriola dumerili, we find that the body adopts a blue-grayish to green-grayish coloration in the upper dorsal part of the body, and this color gradually turns into a silvery white on the sides and completely on the ventral part. It is common to find an amber or dark stripe running diagonally from the mouth, across the eyes, to the back of the head and origin of the first dorsal fin. The caudal fin tends to adopt dark or brownish colors and has a narrow lighter colored posterior margin. It is common for the end of the lower lobe of the caudal fin to be much lighter in color than the rest of the fin, or even white. In juveniles we find 6 irregular dark bands on the body.
The diet of Seriola dumerili consists predominantly of small fish that it hunts solitarily or in small hunting groups. Occasionally, it may also feed on invertebrates.
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