Happy National Dolphin Day! In honour of this awareness day for one of the world's most endearing animals, it'd be appropriate to look at some of the risks that are facing our marine mammal friends.
The fact that dolphins generally still boast some fairly good population numbers means that people don't immediately associate them with being as species under threat...but they are.
Being a marine mammal, Dolphins rely very heavily on their hearing sense to get around, to hunt and to communicate with their fellows. That's because sound travels extremely well in water, 4.5 times faster than in air in fact, while visibility is often greatly reduced. Hearing therefore is a vital part of their survival and any interference with that is a big issue.
Here's the crux of one big threat to the dolphin world then, the amount of sound pollution that is thrown about in our oceans. Noise from ship engines, sonar and radar and marine construction greatly interferes with Dolphin echolocation, putting their survival at risk. As technology is advancing, with ship engines and navigation systems becoming more efficient and less disruptive, this threat is reducing somewhat, but the threat isn't retreating anywhere near as fast as it should.
This disruption to the dolphin's watery world alters their behaviour in a number of ways. Firstly, it can affect their own navigation methods which affect migration and breeding and even could cause such disasters as beaching. Beachings of cetaceans generally, not just dolphins, has seemingly increased in recent years and the interference with echolocation has been pointed at as a potential reason. This is one problem that human technology could sort out quickly and efficiently.
Thanks to the likes of SeaWorld, the humble dolphin and killer whale (which is a type of dolphin) get an awful lot of conservation coverage. They're just one of those animals that people like, like pandas and polar bears. Despite their huge intelligence and all this attention though, they're still threatened by those oldest and most notorious of sea threats. Commercial Fishing and Pollution.
In the case of pollution, it is believed to be the main cause of the extinction of the Yangtze River Dolphin in China. This species, unique to a system of rivers in China, is believed to have gone extinct in the last ten to fifteen years. It so happens to coincide with a huge boost in industrial activity on or around the river systems in which it lived. Extra waste toxicants and pollutants were pumped heavily into these rivers where it lived, clouding up visibility, suffocating the nutrients and fish and as a result, killing off the Yangtze River Dolphin.
Out in the big wide ocean, this is a problem too, as plastic pollution continues to be vast problem. The amount of floating debris gets into the oceans ecosystem by being consumed by fish, which are then consumed by the dolphins, moving all sorts of toxicants and pollutants into their bodies that are not naturally occurring at all. We have this problem too, as we eat a huge amount of fish, much of which may well have had a diet of microbeads and other fragmented pieces of plastic. The larger pieces that might be confused with food, well, they would simply choke a hungry dolphin to death.
Pollution is a great threat to all ocean species, but as dolphins are an indicator in many ways of the health of overall oceans, we'd noticed its effects with them before many others. As a top predator, it's somewhat easier to spot dangers to the food chain when you examine them.
To help reduce this big plastic problem, The Ocean Cleanup has started developing a way to clean the oceans of plastic. This would benefit the entire ocean food chain, including ourselves and the dolphins. This is a problem that affects us as well, and being humans we tend not to care much about things until they affect us. Well, this pollution one does so let's crack on with it. A blog went up on Into The Wild about The Ocean Cleanup, so for more info on that, see here...
Huge movements have been undertaken in recent years to stabilize how we fish our oceans too. By targeting more abundant species so others can repopulate, by trying to farm in a more environmentally friendly way, or by indeed fishing with methods that are less damaging. From whatever angle, it's a big issue. Many larger ocean creatures are affected by this, including the dolphin, as there's a huge amount of what's called 'Bycatch'. Bycatch refers to animals that are caught as a result of the fishing that the fishermen didn't intend to catch. Dolphins are a victim of this, as well as sharks, turtles and huge amounts of fish of a variety of species. With trawling nets that stretch for miles, bycatch is a real issue for the sustainability of the oceans, especially as much of what's caught is just dumped overboard.
Fishing economically would benefit the dolphin hugely as it would a) decrease bycatch and prevent dolphins from being trapped in nets and b) re-stabilize the populations of fish that the dolphins feed on.
This all may seem like a grim reality for one of our fan favourites from the animal kingdom, but it's not all bad news. We're lucky that dolphins are as intelligent and adaptable a species as they are otherwise their populations might be going in the same direction as sharks: sinking.
Whether we decide to help them, or decide to help ourselves and as a result help Dolphins too, it's a glaring point that our oceans need a helping hand. Try in vain as we do to save many species, surely one as popular as the dolphin will get the attention it deserves? Let's hope National Dolphin Day can kick start that process.
You can do your bit by getting involved in conservation and awareness, volunteering and contributing to scientific research. Here's a link to Frontier's Tenerife Whale and Dolphin Conservation project.
By Guy Bezant - Online Journalism Intern
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