Scomber scombrus Linnaeus, 1758, Atlantic Ocean.
OTHER COMMON NAMES
French: Maquereau commun; Spanish: Caballa del Atlantico.
Maximum fork length is 22 in (56 cm), commonly to 19 in (30 cm). Body fusiform, tapering rearward to a very slim caudal peduncle and anteriorly to a pointed snout. Eyes large with socalled adipose eyelids covering front and hind margins of the eye except for a slit over the pupil. Mouth large, filled with small, sharp, conical teeth in upper and lower jaws. Gill rakers, 30–36 on lower limb of first gill arch. Two widely separated dorsal fins, the first with 11–13 spines, the second with 11 or 12 rays. Both second dorsal and anal fins followed by five finlets. Entire body covered with small scales. Swim bladder usually absent. Vertebrae, 31. Upper surface dark steely to greenish blue. Body barred with 23–33 dark transverse bands; belly unmarked.
North Atlantic Ocean, including the Baltic, Mediterranean, and Black seas. Replaced by other species of Scomber in other oceans.
An epipelagic and mesodemersal species, most abundant in cold and temperate shelf areas.
Mackerel are swift-moving, swimming with very short sidewise movements of the rear part of the body and the powerful caudal fin. They need so much oxygen that they must swim constantly to bring sufficient water across their gill filaments. Mackerel gather in dense schools of fish that are approximately the same size and age. They overwinter in moderately deep water along the continental shelf and move inshore and northward in the spring.
FEEDING ECOLOGY AND DIET
Atlantic mackerel are opportunistic carnivores that swallow their food whole. Food is captured by active pursuit or by passive filtration with the gill rakers. Juveniles feed on zooplankton. Adults also eat crustaceans but add squids and small fishes to their diet.
In the western North Atlantic, spawning takes place from Chesapeake Bay to Newfoundland, beginning in the south in spring and progressively extending northward into the summer. Most spawning occurs within 10–30 mi (16–48 km) of shore. Mackerel do not begin spawning until the water has warmed to approximately 46.4°F (8°C). The chief production of eggs takes place at temperatures of 48.2–57.2°F (9–14°C). Maturity is attained at 2–3 years of age. Estimates of fecundity range from 285,000 to 1.98 million eggs for females 12–17 in (307–438 mm) fork length. The eggs are 0.04–0.05 in (1.09–1.39 mm) in diameter, have one oil globule, and generally float in the surface water layer above the thermocline.
SIGNIFICANCE TO HUMANS
Mackerel are delicious fish but do not keep as well as fishes that have less oil in their tissues. There are important fisheries in the northwest Atlantic, northeast Atlantic, and Mediterranean and Black seas. FAO catch statistics for 1991–2000 show catches of 6.16–9.42 thousand tons (5.59–8.55 thousand metric tons) per year by 36 countries. Atlantic mackerel are caught mainly with purse seines. Mackerel also are taken by anglers; the all-tackle world record is a 3-lb (1.2-kg) fish taken off Norway.
Copyright © 2016-2017 Animalia Life | All rights reserved