The black dragonfish, with its truly scary name and appearance reminiscent of mythical dragons, is a fascinating creature of the deep sea. This article delves into the dietary habits of these formidable predators, exploring what they eat and how they hunt in the dark depths of the ocean.
Black Dragonfish: An Overview
The black dragonfish, scientifically known as Idiacanthus atlanticus, is a deep-sea fish belonging to the family Stomiidae. The name Idiacanthus atlanticus comes from the Greek phrases “idia” (“own”) and “Samantha” (“thorn”). Dragonfish are generally members of the Family Stomiidae. The order and class that they come from are Stomiiformes and Actinopterygii. Dragonfish is a name that covers a wide variety of small fish that have similar characteristics. They inhabit mesopelagic to bathypelagic waters, reaching depths of about 2000 m (6,600 ft). These fish are found in a subtropical region of the southern hemisphere, in temperate oceans between latitudes 25°S and 60°S.
These creatures are scary looking with large heads, wider than their body. Their mouths are filled with fang teeth used to capture and kill prey in a single strike. They are sexually dimorphic: females and males are extremely different in size. Adult females reach lengths of about 40 cm (16 inches), while males are significantly smaller, barely growing up to 5 cm (2 inches) in length. Also, males do not have teeth, have no barbel (structure extending from their chin). Females are believed to make a daily migration from the twilight zone to the surface of the ocean. During the daytime, they stay deeper than 500 meters (1,600 ft).
Hunting and Feeding Strategies
Black dragonfish are carnivorous and females have those extremely long fang teeth. They are cunning predators. Although they are strong swimmers, they prefer to lie in wait and ambush unsuspecting fishes and crustaceans. Their dark bodies and transparent teeth help them hide and hunt in the deep ocean.
Like many deep-sea creatures, the common black dragonfish can produce its own light. It has photophores - organs capable of bioluminescence. This light is mainly used to attract prey. Some dragonfishes dangle a luminescent lure from their chins to entice prey. When a tasty morsel comes close, their big jaws open wide, and sharp teeth snap shut.
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What Black Dragonfish Eat
Black dragonfish feed on a variety of marine organisms. While they are top predators, they also face threats from other predators. Meanwhile, they feed on marine invertebrates, algae, insects, shrimps, squids, and larvae.
Malacosteus niger Diet
Malacosteus niger, commonly known as the stoplight loosejaw, is another species of deep-sea fish belonging to the family Stomiidae, or dragonfishes. It is among the top predators of the open mesopelagic zone, and inhabits the mesopelagic and bathypelagic zones. M. niger is a circumglobal species, which means that it inhabits waters ranging from the tropics to the subarctics. While the morphology of M. niger with huge fangs and an enormous gape is typical for its family and suggests adaptations to piscivory, its diet in fact contains a substantial proportion of zooplankton. Some of its documented prey include calanoid copepods, micronekton, decapod shrimps, and other decapods. M. niger digests its prey within a diel cycle, meaning the copepods it consumes at nighttime are digested by the afternoon the following day, which requires it to be constantly feeding on these small prey to sustain its energy. It has been recorded that copepods make up around 69%-83% of M. niger's diet. This suggests that availability of large prey at these depths is often limited. It is suggested that its dominant feeding mode is searching for zooplanktonic prey (copepods in particular) using bioluminescence to illuminate a small search area, since M. niger experiences infrequent encounters with larger prey items. Current research suggests that M. niger has adopted this unique feeding habit in association with the abundance of prey. Recent studies in the eartern Gulf of Mexico indicate that large calanoid copepods are three orders of magnitude more abundant than either fish or shrimp. More research is needed within different regions to confirm this hypothesis. It is suggested that its dominant feeding mode is searching for zooplanktonic prey (copepods in particular) using bioluminescence to illuminate a small search area, with infrequent encounters with larger prey items.
Adaptations for Predation
Black dragonfish possess several unique adaptations that aid in their predatory lifestyle:
- Large Mouth and Fang-like Teeth: Their large mouths and fang-like teeth are perfectly suited for capturing and holding onto prey in the deep sea.
- Bioluminescence: Like many deep-sea creatures, black dragonfish can produce their own light through bioluminescence. This light is used to attract prey.
- Transparent Teeth: They have transparent teeth which help them hide and hunt in the deep ocean.
- Red Bioluminescence: Malacosteus niger's unique adaptation of producing red bioluminescence is only found in two other deep-sea dwelling creatures, Aristostomias and Pachystomias. This rare form of bioluminescence can reach up to 700 nm in the deep-sea and cannot be perceived by green and blue bioluminescent organisms, thus granting M. niger a considerable advantage while hunting for food.
Human Interaction
People use different baits to lure and eventually catch the dragonfish as their food. It is eaten and is often considered to be one of the top marine dishes around the globe. There is no shortage of recipes to show how to properly make dragonfish, depending on the flavor that you enjoy. For instance, one method involves removing the bone and sautéing it with spring onions, red chili paste, and garlic. Some people use it to create a barbecue flavor. The delicacy can be made in many different ways, like the one seen here. As delicious as a dragonfish may be, these fish contain poison sacs and spines that cannot be cooked. Yes.
Conservation Status
NOAA has declared these fish as “not extinct” largely. However, some of them do face the dangers of extinction. The black dragonfish falls under the “not extinct” category.
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