If you practice diving you can encounter the most diverse species of animals, thanks to the incredible diversity of the deep sea. p>
Many believe that scuba diving is an extreme sport, but the truth is that it leaves you with wonderful sensations, where nature surrounds you while you discover unique landscapes. Next we are going to talk about marine curiosities...
Types of feeding
The diet of fish is very diverse. According to their eating habits we can basically classify them into three groups:
- Herbivores: They are very few, both in fresh and marine waters. They eat algae and marine plants.
- Carnivores: are those that feed on worms, crabs, other fish or insects and mollusks. They are sharks or tunas, among others.
- Omnivores: those that feed on animals and plants.
The feeding regime of larvae or juveniles is usually very different from that of adults. Most larvae feed on zooplankton, mainly rotifers, copepods and cladocerans.
Dietary strategies
Depending on the quality or way of eating food, we can also talk about filter-feeding, predatory and detritivorous fish.
- Predators actively pursue their prey to capture them. They are carnivorous animals with a series of characteristics in common; They are fast species, with a hydrodynamic body, they have well-developed vision and smell and, without a doubt, good teeth. Tuna, bonito, barracudas and many sharks are good examples of large predators, devouring large quantities of sardines and similar fish.
- Detritivores feed on organic remains deposited on the seabed. The term detritivores therefore designates omnivores that feed on decomposing plants and animal particles. There are many detritivores among the species that populate the ocean floors, where food is scarce.
- The filters feed on plankton that they separate from the water and concentrate, thanks to certain filtration methods. Among the typical filter feeders we find sardines and anchovies. They have gill rakers, formations derived from the gills with an appearance similar to that of spines that structure a filter where the plankton is retained. The largest fish on our planet, the whale shark (Rhicodon typus), is also a filter feeder. It does not have real teeth like most sharks, but rather they have been reduced and the gill arches are provided with thin lamellae that act as a filter.
Hunting strategies
Some predators prefer to act alone, such as pike - freshwater fish - (Esox lucius), but there is no shortage of those that hunt in groups, such as tunas (Thunnus thynnus), which gather together to chase the fish. schools of fish.
Others, however, prefer to go unnoticed and stalk their prey. The scorpions and scorpionfish are perfectly camouflaged among the rocks, where they wait motionless for a prey to pass nearby and, in this way, catch it by surprise.
Some have the ability to generate electrical discharges, such as the torpedo (Torpedo torpedo) or eels (Electrophorus electricus) among others, in order to defend themselves or stun prey.
To attract their victims, there are fish that use lures, such as the anglerfish (Lophius piscatorius), which has the first dorsal fin very reduced and modified so that when shaken it looks like a worm. The rat (Uranoscopus scaber) is a sedentary fish that lives buried in the seabed, leaving only its eyes and a mouth tentacle exposed, which it uses to attract its prey.
Abyssal species usually have special organs, called photophores, which have the ability to emit light. These photophores are often strategically arranged in the mouth or sensory barbs to attract other fish.
Curious ways to obtain food
There are a large number of species that associate with others to obtain some benefit. The remora, for example, has a suction cup on the dorsal part of its head, which allows it to stick to sharks or other large fish, so that it can take advantage of the remains of shark food for free. Remoras can also feed on the external parasites of the sharks, which benefits them mutually.
The cleaner fish (Labroides dimidiatus) are some small fish, belonging to the wrasse family, that feed on the external parasites of other fish. They can even enter the mouths of fish much larger than them without the risk of being eaten. A fish that needs the cleaning services of this species either spreads its fins or opens its mouth to show it the area to be cleaned. However, there is a fish, the false cleaner (Aspidontus taeniatus), which imitates the colors and movements of the real one, so that other fish waiting to be cleaned receive, On the contrary, bites on their fins.
Locate the food
Fish have developed a wide variety of mechanisms to detect food or to attract their prey, some of them really curious.
Fish have a sixth sense, the lateral line, special scales to which nerve endings reach and which inform the fish of the vibrations of the water. With it they can detect possible predators or preythat are around them from a certain distance. It is an especially useful organ in environments with poor visibility.
Some fish such as the mullet (Mullus surmuletus) have a pair of sensory barbs in their mouths that they use to search the bottom in search of something appetizing. Smell and hearing also play an important role in detecting prey.
