The gulper shark (Centophorus granulosus) is a deep water shark that tends to live at depths of between 200 and 1200 meters. They are known to reach 5 feet as a maximum length, and feed mainly on small fishes and crustaceans. The gulper shark was previously thought to be common, and can be found in many of the worlds seas, although now it is becoming more and more threatened due to a combination of factors.
One of the adaptations that the gulper shark has made in order to live at deep depths is that it has distinctively large eyes. These are greenish in color, and are reflective in most kinds of light, enabling the shark to capture all the light it can in dark water. Being able to see better than many species is probably how the shark hunts its prey, sneaking up and then suddenly attacking with a burst of speed.
Due to the fact that the gulper shark lives at great depths, it doesn’t tend to breed as often as shallow water species of shark. Also the gestation period of the gulper shark is about two years, which is a long time for a species of its relatively small size. This basically means that when members of the species are killed by unnatural means, such as fishing, that the species as a whole is more affected. The faster a species can breed and so make up its number, then the less the effect of hunting will be.
Like many deep water species, the fact that they don’t breed very often does have its benefits for the gulper shark as well. They tend to live longer than shallow water species for example, and also tend to have fewer predators due to the lower concentrations of species at greater depths. Also the long gestation period means that the young are born live, and are ready to hunt by themselves immediately. This also reduces the amount of young that are eaten by predators, or killed before reaching maturity due to being born in a more vulnerable state.
The main reason that gulper sharks are becoming more threatened is due to the fact that they are fished heavily in a number of countries. Due to the fact that they are a deep water species, they also don’t tend to have as much support from public opinion or protection of other species such as cod or crabs, which have strict quotas.
Similarly being a shark, many people tend to feel less support for gulpers than for other kinds of fish due to the fact that some sharks are dangerous. Because of this people may feel more obliged to kill them, or not to mind that they are begin killed, thinking that they are making people safer. In reality upsetting the balance of life even at great depths often has dire consequences for other species in the food chain.
In some countries the gulper shark is caught to be eaten, particularly in Asian markets, although this has not been as widely adopted in the United States or Europe. Other than for eating, the gulper shark is also caught for processing as fishmeal and fish oil. Having a comparatively large liver, the gulper shark is valued for use in making fish oil.
.Gulper sharks live exclusively at depths too great for them to ever encounter human divers or swimmers. If they ever did meet humans however, they would be far too small to pose any kind of threat, and would likely shy away from anything so large in the water. In the wild, larger creatures in the water are usually predators , and so most species will tend to avoid them if they can. The gulper shark is also only suited to catching very small prey, probably no larger than a couple of feet long.
Despite the fact that the gulper shark is being widely and heavily fished, relatively little is known about it and its behaviors in the wild. This is mainly due to the fact that it is difficult to observe in its natural environment. Similarly although they are known to be Ovoviviparous (give birth to live young), little else is known about their mating migrations, or even if they have any.
