California yellowtail, Seriola lalandi (Biology – distribution- conservation and aquaculture) – Video

This short clip was taken at the Sea World, California, USA
Source: Description: Abdel Rahman El Gamal

Introduction: The California yellowtail, Seriola lalandi has several common names including Yellowtail Kingfish, Amberjack, Yellowtail Amberjack and more names. The yellow caudal fin of the species is behind several of the common names. This fish has a distinctive golden brown stripe running laterally from the snout to the tail. While it is common to find fish of about 12 years, there are specimens of about 30 years of age. Yellowtail is a highly prized game fish.

Description: The species are long with streamlined bodies of greenly blue color on the dorsal surface shading to silvery white beneath. Fish fins are yellowish. The Yellowtail Kingfish can grow up to 2.5 m as total length and can weigh up to 70 kg with records close to 100 kg. However, most caught off piers are fish under 5 kg in weight.

California yellowtail are solitary or they may occur in small groups. The schools of juveniles are generally found in offshore waters, often near or beyond the continental shelf. The species is a powerful swimmer that is adapted to a pelagic life style and hence is prized by anglers.

These fish are equipped with sensory cells (neuromasts) which are located separately on fish body surface or in lateral line canals. This sensory system gives fishes a distant touch sense, and enables the detection and reaction to moving items in the water and coordinates fish movements during the schooling.

Distribution and habitats: The Yellowtail Kingfish are widely distributed in tropical and temperate waters of the southern hemisphere and the northern Pacific. The species prefers warmer water (18-24°C) although they are occasionally found in cooler water.
The Yellowtail Kingfish is a pelagic, schooling fish, usually seen as adults in small to large numbers. In general they inhabit rocky reefs and adjacent sandy areas in coastal waters and occasionally enter estuaries. They are found from shallow water down to depths of around 50 m, although have been caught from over 300 m.

Feeding Habits: California Yellowtail are opportunistic and carnivore daytime feeders. The feed on variety of species whereas sardines, anchovies, mackerels, squid, crab, and smelts are common in the yellowtail’s diet. California yellow tail feeds predominantly in the morning and late afternoon.

Reproduction and life history: Yellowtail fish becomes sexually mature at about 2-3 years of age. California Yellowtail form spawning aggregations in offshore waters which makes them vulnerable to fishermen gears. Young brood female may spawn only once during the spawning season while older females spawn several times during the spawning season. Fecundity as calculated as number of eggs/female increases with the female size and would range from about 400,000 up to about 4 million eggs for larger/older fish of about 15-kg female. It may worth mentioning that the hatchery technology has been developed where the farming of the species does exist.

California yellow tail aquaculture: The rapid growth rate of California yellowtail coincided by the high demand stimulated the investments in aquaculture projects. Fish can reach marketable size of 3 kg in 12–15 months. California yellowtail, Seriola lalandi proved to be a suitable candidate for marine aquaculture. Because the juveniles of California yellowtail are not easily available from the wild, hatchery produced juveniles are produced for aquaculture projects whereas the largest operations do exist in Australia. Aquaculture initiatives have been attempted in cages and land-based systems in New Zealand supported by hatchery-produced fingerlings. Japan is the key importer and consumer of California yellowtail whereas the species is also cultured and consumed as sashimi.

Conservation measures: Even though it does not seem there is serious conservation measures applied to the species, the species overfishing called for some governing regulations especially related to the commercial fishery of California yellowtail. For example, minimum size of caught yellow tail has been stated to be 70 cm. Moreover, the catch limit of the species has been limited to 200 kg/person during the period from May 1st through August 1st which coincides with the spawning season. The regulation is applied also to the California recreational fishery, there is a 10 fish bag limit, and 5 of these fish must be larger than 60 cm. In general, it is believed that most world fishery resources are largely unregulated.

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