One of the most unique and fascinating creatures a Scuba diver can come across on a dive, is the rarely spotted peculiar looking sawfish. With a long snout interspersed with sharp saw-like toothy scales, the sawfish is a creature difficult to not identify.
Sawfish though they may resemble a shark with a saw nose; they in fact belong to the family of Rays. They are also considered one of the more highly endangered marine species in existence, and are now protected under the highest protection level of the Endangered Species list. Often growing up to a length of 7m (23ft) and with a lifespan of 25-30 years, the numbers of this species has dwindled over the centuries due to excessive hunting for traditional medicine and souvenirs.
Sawfish are found primarily in the tropical and sub tropical waters of the Atlantic and the Indo-Pacific . 5 out of the 8 different species of sawfish are found in Australia, and are known to live in fresh water river estuaries and large lakes most notably known to be found in Lake Nicaragua.
The saw like teeth located on the Sawfishes rostrum (nose) is in fact a kind of scale known as denticles that the sawfish uses to dig up its prey of crustaceans buried in the sea bed. It’s real set of teeth are located in its mouth that the sawfish uses to devour its prey. The strange looking rostrum or snout also contains motion- and electro-sensitive pores that allow sawfish to detect movement of prey buried in the ocean floor.
The Sawfish is a nocturnal predator, feeding on mainly a diet of crustaceans, prawns, crabs, and other invertebrates, and may sometimes feed on smaller fish, slashing at them with its saw-like snout before devouring them. Being able to traverse between brackish and fresh water, sawfish are often found hidden in the muddy bottom of river estuaries making them a rather unique marine creature.
If you are looking to Scuba Dive with Sawfish, the chances you will ever come across one are highly unlikely, being firstly endangered and nocturnal creatures often lying buried in the seabed during the day. The best chance of spotting a sawfish is in Australia’s Queensland, the Northern Territory and Western Australia, where currently the largest existing population of sawfish are known to exist. In freshwater, the sawfish is known to be most commonly sighted in Lake Nicaragua, where overfishing had caused the population to drastically decline until the government outlawed the hunting of sawfish from the lake.
Photos from flickr by: greyloch, tricky ™, istolethetv
This really brings back memories, I used to swim with these guys in the Daly River, Northern Territory. We were about 200 kms from the river mouth, in absolute freshwater, and there were two of them that were pretty permanent residents in the area. They were the gentlest creatures – absolute sweethearts, and a delight to swim with!
Lucky you! Most of us are lucky enough if we spot a sawfish in an aquarium.
They shared that part of the river with freshwater stingrays, salt and fresh water crocodiles, huge water pythons, giant freshwater prawns and giant barramundi, some over 6 ft in length. And also with the subject of my research studies, the pig nose turtle, which grows to over 1/2 a metre in size. It was a very busy river