Hello and welcome back to another one of my blogs for Sairee Cottage Diving, Koh Tao. This time I will be telling you about the various ways that marine life defend and protect themselves from predators. It is important for divers and, even more so, for underwater photographers to be aware of the signs that fish are telling us to back off. Being aware of this means that we are being a safer diver and, as photographers, we can orchestrate some great shots without stressing these creatures out.
Firstly, one of the most common ways for fish to deter predators to stick together as there really is safety in numbers. By schooling together in big groups it makes it almost impossible for predators to pick out any one individual of the group. A big group means many eyes on the look out for predators and not being caught off guard. Also the odds of being picked out of such a big crowd are very small compared to being alone in open water. A large school of fish, for photographers, makes for a very dramatic shot.
Another common way that marine life evade predators is with great speed and maneuverability. If they can’t catch you they cant eat you! Many fish that grow up to be top predators use speed to hunt however, as juveniles, they are often vulnerable to predators so speed is key for survival. Examples of those that use speed to evade being eaten are, tuna, jacks, mackerels and juvenile sharks. When photographing such subjects, the shutter speed must be pretty fast. It is also important that you do not turn your strobes up too high because these fish usually have very shinny reflective bodies.
Often the best form of defense is to counter attack! Many marine species have very effective defenses. One of which is the Orange Spine Surgeon Fish, which is often found on the south east side of Koh Tao. These beautiful fish have a set of scalpel sharp spines at the base of their tail, much like stingrays, to give any potential predators a good reason to leave them alone. Photographers must keep a safe distance from these kinds of creatures. The Orange Spined Surgeon Fish and the Stingray, however, are actually very timid and are often very hard to get close to. More dangerous species that use attack as a defense are the stone fish family. These include lion fish with their flamboyant elongated dorsal spines each with a strong nero-toxin within. There are also the stone fish themselves and the closely related scorpion fish that not only have the strongest sting in the sea they are also extremely well camouflaged, yet another great form of self defense but also doubles up as a way of hiding from potential prey. This means they can strike when their prey is close and has no idea of the danger.
For many types of marine life, the safest option is to stay at home! Hermit crabs are the best at this and they do so by finding an empty sea-shell and climbing inside. Their strange shaped bodies fit into the stolen shell and they are able walk around with it. The rare time we get to see a one of these creatures without a shell is when they out grow their current home and need to upgrade to a bigger one, often by evicting another hermit crab. Other types of marine life prefer to burrow into the sand. An example of this is the Goby. The Goby is an interesting fish as it has a rare partnership with another species.. the Shrimp.
These unlikely pair keep each other safe beyond just the burrow in the sand, as many creatures also do. The Goby and the shrimp have a symbiotic relationship in which the shrimp digs out the burrow in which the Goby is unable to do itself. The shrimp, however, has very poor eyesight so the goby acts as look out so that they are both safe from predators. Any burrowing creatures such as gobys, jawfish, snakes, eels or mantas shrimp make for great photography subjects, as they don’t swim away. As long as you stay relaxed and keep your movements very slow, they will get used to you being there and they will come out of their burrow to feed or tend to their home.
In summery, those are some of the most common defense techniques used by a wide range of marine species. There are also some very bizarre and unique forms of defense used by other marine life, for example, the puffer fish. The Puffer fish, at first glance, could be considered an easy target for predators, with its un-streamlined body and clumsy movements but they do have plenty of spines that lay flat along their body that cannot be seen until the fish is stressed. Once they feel threatened they suck in water to inflate their bodies and push up all of their spines making them too big to for some predators. The sea cucumber too has an interesting defense mechanism with its toxic and extruding sticky tubes that can entangle and deter those predators thinking that they have stumbled upon an easy meal.
Every species of marine life has some kind of defense. By knowing what it is or at least being able to recognize these defense techniques means that we are able to be safer underwater and to, of course, maximize our potential for excellent photographs.