The giant trevally (ulua) reaches sexual maturity at 54 to 61 cm in length and 3 to 4 years of age, although many authors narrow this down to 60 cm and 3 years of age. Sex ratio estimates from the Hawaiian Islands suggest that the population is slightly skewed toward females, with the male:female ratio being 1:1.39. Spawning occurs during the warmer months in most locations, although the exact dates differ by location. In southern Africa this occurs between July to March, with a peak between November and March; in the Philippines between December and January with a lesser peak during at June; and in Hawaii between April and November with a major peak during May to August. Lunar cycles are also known to control the spawning events, with large schools forming in certain locations at specific phases of the moon in Hawaii and the Solomon Islands. Locations for spawning include reefs, the reef channels and offshore banks. Sampling of schools prior to spawning suggests the fish segregate into schools of only one sex, although the details of this are still unclear. Observations in the natural habitat found spawning occurred during the day immediately after and just before the change of tide when there were no currents. Giant trevally gathered in schools of over 100 individuals, although ripe individuals occurred slightly deeper; around 2 to 3 m above the seabed in groups of 3 to 4, with one silver female being chased by several black males Eventually a pair would sink down to a sandy bottom, where eggs and sperm were released. The fish then diverged and swum away. It appears that that each individual spawns more than once in each period, with only part of the gonads ripe in spawners. Fecundity is not known, although females are known to release several thousand eggs on capture during the spawning process. Eggs are described as pelagic and transparent in nature.

The giant trevally is a powerful predatory fish, and is an apex predator in most environments; from the estuaries it inhabits as a juvenile to the outer reefs and atolls it patrols as an adult. Hunting appears to occur at different times of the day in different areas of its range; off South Africa it is most active during the day, especially at dawn and dusk, while off Zanzibar and Hong Kong it is said to be nocturnal in its habits. The species diet has been determined in several countries and habitats, with this research finding the diet generally varies slightly between locations and age. In all but one study (which was of juveniles), the giant trevally dominantly takes other fishes, with various crustaceans, cephalopods and occasionally molluscs making the remainder of the diet. In Hawaii the species has a predominantly fish based diet consisting of Scaridae and Labridae, with crustaceans, including lobsters, and cephalopods (squid and octopus) making up the remaining portion of the diet. The large number of reef fishes suggests that it spends much of its time foraging over shallow-water reef habitats, but the presence of squid and the schooling carangid Decapterus macarellus indicates exploitation of more open-water habitats as well. Off Africa the diet is similar, consisting mostly of fish including eels, with minor squid, octopus, mantis shrimps, lobsters and other crustaceans. Younger fish inside Kaneohe Bay, Hawaii showed the only instance when crustaceans were preferred over fish; stomatopods, shrimps and crabs were the most common prey taken at 89% of stomach content by volume, with fish, mostly of the family Blennidae, making up only 7% of the stomach contents. Estuarine fish in both Hawaii and Australia have mostly fish-based diets, with crustaceans such as prawns and amphipods also of importance, and are known to take more novel prey such as spiders and insects in these habitats. There have also been reports of juvenile turtles and dolphins being found within the stomach contents of larger giant trevally. Studies of different size classes of fish have found the diet does change with age in some locations, with the changes relating to an increased volume of fish taken.

The crevalle jack is one of the largest members of Caranx, growing to a known maximum length of 124 cm and a weight of 32 kg, although are generally rare at lengths greater than 60 cm. Unverified reports of fish over 150 cm may also be attributable to this species. The crevalle jack is morphologically similar to a number of other deep bodied carangids, having an elongate, moderately compressed body with the dorsal profile more convex than the ventral profile, particularly anteriorly. The eye is covered by a well-developed adipose eyelid, and the posterior extremity of the jaw is vertically under or past the posterior margin of the eye. The dorsal fin is in two parts, the first consisting of 8 spines and the second of 1 spine followed by 19 to 21 soft rays. The anal fin consists of 2 anteriorly detached spines followed by 1 spine and 16 or 17 soft rays. The pelvic fins contain 1 spine and 5 soft rays while the pectoral fins contain 20 or 21 soft rays. The caudal fin is strongly forked, and the pectoral fins are falcate, being longer than the length of the head. The lateral line has a pronounced and moderately long anterior arch, with the curved section intersecting the straight section midway below the second dorsal fin. The straight section contains 23 to 35 very strong scutes, with bilateral keels present on the caudal peduncle. The chest is devoid of scales with the exception of a small patch of scales in front of the pelvic fins. The upper jaw contains a series of strong outer canines with an inner band of smaller teeth, while the lower jaw contains a single row of teeth. The species has 35 to 42 gill rakers in total and there are 25 vertebrae present.

From Wikipedia, the free encyclopedia Taxonomy and phylogeny The crevalle jack is classified within the genus Caranx, one of a number of groups known as the jacks or trevallies. Caranx itself is part of the larger jack and horse mackerel family Carangidae, a group of percoid fishes in the order Perciformes. The species belongs to [...]

The crevalle jack, Caranx hippos (also known as the common jack, black-tailed trevally, couvalli jack, black cavalli and yellow cavalli) is a common species of large marine fish classified within the jack family, Carangidae. The crevalle jack is distributed across the tropical and temperate waters of the Atlantic Ocean, ranging from Nova Scotia, Canada to Uruguay in the west Atlantic and Portugal to Angola in the east Atlantic, including the Mediterranean Sea. The crevalle jack is distinguishable from similar species by its deep body, fin colouration and a host of more detailed anatomical features including fin ray and lateral line scale counts. It is one of the largest fish in the genus Caranx, growing to a maximum known length of 124 cm and a weight of 32 kg, although is rare at lengths greater than 60 cm. The crevalle jack inhabits both inshore and offshore waters to depths of around 350 m, predominantly over reefs, bays, lagoons and occasionally estuaries. Young fish dispersed north by currents in the eastern Atlantic are known to migrate back to more tropical waters before the onset of winter; however if the fish fail to migrate, mass mortalities occur as the temperature falls below the species tolerance limits.

The wahoo (Acanthocybium solandri) is a scombrid fish found worldwide in tropical and subtropical seas. It is best known to sports fishermen, as its speed and high-quality flesh make it a prize game fish. In Hawaii, the wahoo is known as ono. Many Hispanic areas of the Caribbean and Central America refer to this fish as peto.
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Cobia (Rachycentron canadum)—also known as black kingfish, black salmon, ling, lemonfish, crabeaters, aruan tasek, etc.—are perciform marine fish, the sole representative of their family, the Rachycentridae.

Description

Attaining a maximum length of 2 metres (78 inches) and maximum weight of 68 kilograms (150 pounds), cobia have elongate fusiform (spindle shaped) bodies and broad, flattened heads. Their eyes are small and their lower jaw projects slightly past the upper jaw. On the jaws, tongue and roof of the mouth are bands of villiform (fibrous) teeth. Their bodies are smooth with small scales, their dark brown coloration grading to white on the belly with two darker brown horizontal bands on the flanks. These may not be prominent except during spawning when cobia lighten in colour and adopt a more prominently striped pattern. The large pectoral fins are normally carried horizontally (rather than vertically as shown for convenience in the illustration), so that, as seen in the water they may be mistaken for a small shark. When boated, the horizontal pectoral fins enable the cobia to remain upright so that their vigorous thrashing can make them a hazard. The first dorsal fin is composed of six to nine independent, short, stout, and sharp spines. The family name Rachycentridae, from the Greek words rhachis meaning “spine” and kentron meaning “sting,” is an allusion to these dorsal spines. Mature cobia have forked, slightly lunate tail fins with most fins being a dark brown. They lack air bladders.

White croaker (Genyonemus lineatus) is a species of croaker occurring in the Eastern Pacific. White croakers have been taken from Magdalena Bay, Baja California, to Vancouver Island, British Columbia, but are not abundant north of San Francisco. White croakers swim in loose schools at or near the bottom of sandy areas. Sometimes they aggregate in the surf zone or in shallow bays and lagoons. Most of the time they are found in offshore areas at depths of 3 to 30 meters (10 to 100 feet). On rare occasions they are fairly abundant at depths as great as 200 meters (600 feet).

Scomberomorus commerson, is a mackerel of the Scombridae family. It is found in a wide ranging area centering in South-east Asia but as far west as the east coast of Africa and from the Middle East and along the northern coastal areas of the Indian Ocean, and as far east as Fiji in the South West Pacific ocean. They are common down both sides of Australia as far south as Perth on the west coast and Sydney on the east coast. They are also found as far north as China and even Japan.

Menticirrhus americanus – Southern Kingfish: This species grows to 20 inches (51 cm) in length. Seven to eight dark bands mark the sides which shade from dusky above to almost white on the belly. They are found from the Western Caribbean Sea to Cape Cod and most of South and Central America’s east coast, over sand or mud in depths of at least 5 feet (1.5 m). This species is prized for its flesh, and is fished both commercially and recreationally.