From the Denmark Strait to Cape Verde, the black scabbardfish (Aphanopus carbo) is a bathypelagic cutlassfish of the Trichiuridae family that can be found on both sides of the Atlantic Ocean and at undersea rises. Aphanopus intermedius, also known as the intermediate scabbardfish, coexist geographically with the black scabbardfish. During its life cycle, this fish migrates clockwise due to reproductive and feeding patterns.
Black scabbardfish is deep-sea organisms that can be found in abundance between 800 and 1300 meters below the surface. They’re primarily caught in mixed trawl fisheries with other deep-water species, and they’re extremely vulnerable to overfishing. This species is extremely valuable commercially, with yearly catches of up to 14,000 tonnes. In some parts of the Northeast Atlantic, this species’ high abundance is dwindling. The black scabbardfish coexists with Aphanopus intermedius, also known as the intermediate scabbardfish, in terms of space.
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The body of the black scabbardfish is extraordinarily elongated, with a height of around one-eighth of the typical length of up to 1.1 m. The nose is long and slender, with powerful fang-like fangs. There are 34 to 41 spines and 52 to 56 soft rays on the dorsal fin. Two spines and 43 to 48 soft rays make up the anal fin. In juveniles, the pelvic fins are associated with a single spine, but in adults, they are completely missing.
It’s a coppery black with just an iridescent sheen. Juveniles are thought to be mesopelagic, meaning they live in depths of 100 to 500 meters. The insides of the mouth and the cavities of the gills are black. The black scabbardfish’s short, elongated body, pointed head, and the long dorsal fin is all designed for quick swimming. For efficient predation, this fish possesses a huge terminal mouth with enormous fang-like teeth. It has a coppery-black coloring with an iridescent sheen to help it blend in. The fish’s big eyes, which measure roughly 18 percent of its head length in diameter, are large enough to aid seeing in low light.
At roughly 80 cm in length, they reach sexual maturity. The larvae and eggs are both pelagic, floating with the plankton. The black scabbardfish is an integration of various species, which means it can reproduce many times during its lifetime. It’s also a total spawner, which means it lays all of its eggs in one go throughout each breeding season. It also has determined fecundity, which means that before spawning, all of the eggs are oocytes in the ovary.
Females are believed to be able to spawn over an 8-year period, but skip spawning is possible. Females devote their energy to large-scale migration and growth when nonreproductive males are intermingled with spawning adults, and they participate in skip spawning. Adult fish that are mature and ready to spawn have only been seen in the last part of the year in a few sites, including Madeira, the Canaries, and Africa’s northwest coast.
From April through August, females are dominant, and the breeding season runs from September to December, with a high number of pre-spawning and spawning females. Most females have spawned between December and March. Males in development can be seen all year, but especially from March to August. From July through November, pre-spawning males are more plentiful.
From December through April, postspawning males are just as common as females. In general, developing females are more common in Madeiran waters in the spring, and their reproductive cycles continue there, whereas females on the mainland of Portugal begin to suffer from generalized atresia in July.
The black scabbardfish could be seen at various phases of development throughout its life in the Northeast Atlantic. During the months of October and December, the black scabbardfish spawns near the Madeira Islands and the Canary Archipelago. They are assumed to then migrate north to cooler waters to feed and grow. When they reach adulthood, they migrate south to the waters around Portugal, where they stay until they achieve reproductive maturity, at which point they migrate to their nesting sites.
Crustaceans, cephalopods, mesopelagic fish, shrimp, teleost fish, and blue whiting are all eaten by black scabbardfish.