Mackerel in the context of Fish migration

Longline fishing, or longlining, is a commercial fishing angling technique that uses a long main line with baited hooks attached at intervals via short branch lines called snoods or gangions. A snood is attached to the main line using a clip or swivel, with the hook at the other end. Longlines are classified mainly by where they are placed in the water column. This can be at the surface or at the bottom. Lines can also be set by means of an anchor, or left to drift. Hundreds or even thousands of baited hooks can hang from a single line. This can lead to the death of many different marine species known as bycatch. Longliners – fishing vessels rigged for longlining – commonly target swordfish, tuna, halibut, sablefish and many other species.

In some unstable fisheries, such as the Patagonian toothfish, fishermen may be limited to as few as 25 hooks per line. In contrast, commercial longliners in certain robust fisheries of the Bering Sea and North Pacific generally run over 2,500 hand-baited hooks on a single series of connected lines many miles in length.

Worthing (/ˈwɜːrðɪŋ/ WUR-dhing) is a seaside town and borough in West Sussex, England, at the foot of the South Downs, 11 miles (18 km) west of Brighton, and 18 miles (29 km) east of Chichester. With a population of 113,094 and an area of 12.5 square miles (32.4 km), the borough is the second largest component of the Brighton and Hove built-up area, the 15th most populous urban area in the United Kingdom. Northern parts of the borough, including the Worthing Downland Estate, form part of the South Downs National Park. In 2019, the Art Deco Worthing Pier was dubbed the best in Britain.

Dating from around 4000 BC, the flint mines at Cissbury and nearby Church Hill, Blackpatch and Harrow Hill are amongst the earliest Neolithic monuments in Britain. The Iron Age hill fort of Cissbury Ring is one of Britain's largest. The recorded history of Worthing began with the Domesday Book. Worthing is historically part of Sussex, mostly in the rape of Bramber; Goring, which forms part of the rape of Arundel, was incorporated in 1929. Worthing was a small mackerel fishing hamlet for many centuries until, in the late 18th century, it developed into an elegant Georgian seaside resort and attracted the well-known and wealthy of the day. In the 19th and 20th centuries, the area was one of Britain's chief market gardening centres.

A tuna (pl.: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: 50 cm or 1.6 ft, weight: 1.8 kg or 4 lb) up to the Atlantic bluefin tuna (max length: 4.6 m or 15 ft, weight: 684 kg or 1,508 lb), which averages 2 m (6.6 ft) and is believed to live up to 50 years.

Tuna, opah, and mackerel sharks are the only species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, and is among the fastest-swimming pelagic fish—the yellowfin tuna, for example, is capable of speeds of up to 75 km/h (47 mph).

Roe, (/roʊ/ ROH) or hard roe, is the fully ripe internal egg masses in the ovaries, or the released external egg masses, of fish and certain marine animals such as shrimp, scallop, sea urchins and squid. As a seafood, roe is used both as a cooked ingredient in many dishes, and as a raw ingredient for delicacies such as caviar.

The roe of marine animals, such as the roe of lumpsucker, hake, mullet, salmon, Atlantic bonito, mackerel, squid, and cuttlefish are especially rich sources of omega-3 fatty acids, but omega-3s are present in all fish roe. Also, a significant amount of vitamin B₁₂ is among the nutrients present in fish roes.

Bonitos are a tribe of medium-sized, ray-finned, predatory fish in the family Scombridae, which it shares with the mackerel, tuna, and Spanish mackerel tribes, and also the butterfly kingfish. Also called the tribe Sardini, it consists of eight species across four genera; three of those four genera are monotypic, having a single species each. Bonitos closely resemble the skipjack tuna, which is often called a bonito, especially in Japanese contexts.

The mackerel, tuna, and bonito family, Scombridae, includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies. All species are in the subfamily Scombrinae, except the butterfly kingfish, which is the sole member of subfamily Gasterochismatinae.

Scombrids have two dorsal fins and a series of finlets behind the rear dorsal fin and anal fin. The caudal fin is strongly divided and rigid, with a slender, ridged base. The first (spiny) dorsal fin and the pelvic fins are normally retracted into body grooves. Species lengths vary from the 20 cm (8 in) of the island mackerel to the 4.58 m (15 ft 1⁄2 in) recorded for the immense Atlantic bluefin tuna.

Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D deficiency can also be caused by inadequate nutritional intake of vitamin D; disorders that limit vitamin D absorption; and disorders that impair the conversion of vitamin D to active metabolites, including certain liver, kidney, and hereditary disorders. Deficiency impairs bone mineralization, leading to bone-softening diseases, such as rickets in children. It can also worsen osteomalacia and osteoporosis in adults, increasing the risk of bone fractures. Muscle weakness is also a common symptom of vitamin D deficiency, further increasing the risk of falls and bone fractures in adults. Vitamin D deficiency is associated with the development of schizophrenia.

Vitamin D can be synthesized in the skin under exposure to UVB from sunlight. Oily fish, such as salmon, herring, and mackerel, are also sources of vitamin D, as are mushrooms. Milk is often fortified with vitamin D; sometimes bread, juices, and other dairy products are fortified with vitamin D. Many multivitamins contain vitamin D in different amounts.

Hemiramphidae is a family of fishes that are commonly called halfbeaks, spipe fish or spipefish. They are a geographically widespread and numerically abundant family of epipelagic fish inhabiting warm waters around the world. The halfbeaks are named for their distinctive jaws, in which the lower jaws are significantly longer than the upper jaws. The similar viviparous halfbeaks (family Zenarchopteridae) have often been included in this family.

Though not commercially important themselves, these forage fish support artisanal fisheries and local markets worldwide. They are also fed upon by other commercially important predatory fishes, such as billfishes, mackerels, and sharks.

Trolling is a method of fishing where one or more fishing lines, baited with lures or bait fish, are drawn through the water at a consistent, low speed. This may be behind a moving boat, or by slowly winding the line in when fishing from a static position, or even sweeping the line from side-to-side, e.g. when fishing from a jetty. Trolling is used to catch pelagic fish such as salmon, mackerel and kingfish.

In American English, trolling can be phonetically confused with trawling, a different method of fishing where a net (trawl) is drawn through the water instead of lines. Trolling is used both for recreational and commercial fishing whereas trawling is used mainly for commercial fishing.

Mackerel is an important food fish that is consumed worldwide. As an oily fish, it is a rich source of omega-3 fatty acids. The flesh of mackerel spoils quickly, especially in the tropics, and can cause scombroid food poisoning. Accordingly, it should be eaten on the day of capture, unless properly refrigerated or cured.

Drammensfjord (English: Drammen Fjord) is a fjord in along the border of Akershus and Buskerud counties in Norway that connects to Ytre Oslofjord on the west side. It stretches about 30 kilometres (19 mi) to the north and northeast. The Drammenselva river discharges into the head of the fjord. The fjord shares its name with the city of Drammen, which is located at the head of the fjord. Drammen Municipality is located on its west and north sides. The land on the east side of the fjord is called Hurumhalvøya or the Hurum peninsula and this is located in Asker Municipality. The peninsula lies between the Drammensfjord and the Oslofjord.

The fjord narrows to a strait at Svelvik on the west side and Verket in Asker on the east side. The strait is crossed by an automobile ferry. This narrowing, some 200 metres (660 ft) broad and 10 metres (33 ft) deep, combined with the large freshwater inflow from the river Drammenselva (one of Norway's largest rivers) and from the river Lierelva, results in the water north of the strait being brackish. On the surface the water is fairly fresh, resulting in bathing areas that are free of jellyfish, while deeper the water has a higher salt concentration, with saltwater fish such as cod, pollock, flounder, and mackerel.

The race-built galleon was a type of war ship built in England from 1570 until about 1590. Queen's ships built in England by Sir John Hawkins and his shipbuilders, Richard Chapman, Peter Pett and Mathew Baker from 1570 were galleons of a "race-built" design. The description derived from their "raced" or razed fore-and aft-castles, which, combined with their greater length in relation to their beam, gave them a purposeful, sleek look. Their builders described them as having "the head of a cod and the tail of a mackerel". These ships were purposely designed and built to the new design, not razeed older galleons.

In 1570, Hawkins began a partnership with Richard Chapman to build or rebuild warships for the Queen's Navy Board at Deptford Dockyard. The prototype of these new style galleons was the 295-ton Foresight in 1570, built by Chapman. Her success was followed in 1573 by the 360-ton Dreadnought (built by Matthew Baker) and 350-ton Swiftsure (built by Peter Pett). In 1577 the 464-ton Revenge was built, together with the smaller (132-ton) Scout. Following Hawkins's appointment as Treasurer of the Navy in 1578, further vessels along similar lines emerged during the next decade, as the Dainty in 1588. All these ships were to do sterling service during the fight against the Spanish Armada.

Oily fish, also known as blue fish or fatty fish, are fish species with oil (fats) in soft tissues and in the coelomic cavity around the gut. Their fillets may contain up to 30% oil, although this figure varies both within and between species. Examples of oily fish include small forage fish such as sardines, herring and anchovies, and other larger pelagic fish such as salmon, trout, tuna, swordfish and mackerel.

Oily fish can be contrasted with whitefish, which contain oil only in the liver and in much less overall quantity than oily fish. Examples of whitefish are cod, haddock and flatfish. White fish are usually demersal fish which live on or near the seafloor, whereas oily fish are pelagic, living in the water column goes from the bottom.

The Atlantic bonito (Sarda sarda) is a large mackerel-like fish of the family Scombridae. It is common in shallow waters of the Atlantic Ocean, the Mediterranean Sea, and the Black Sea, where it is an important commercial and game fish.