The topic of habitat destruction is an interesting topic to me especially when we relate it to tropical fish or really fish in general.
The reason is, we hardly ever think about it!
I mean seriously, I bet when you read habitat destruction, you were thinking about Gorillas in Virunga National Park (of Congo, and the other parks bordering Rwanda and Uganda)
or Orang Utans of Borneo,
or maybe the Chimpanzees of West Africa.
You would never have thought of fish along your nearest coast right?
Well that, ladies and gents is the reality and why its quite a huge mess.
Humankind just loves living by some body of water. Perhaps its some kind of innate need to be near water for those that are rich enough to have piped water.
For others who cant afford it, or just dont have it, it simply is a necessity to be near water, be it for the food in terms of the fish and other creatures in the water or for the daily needs of drinking and washing and what have you.
So there we have it, loads of humanity have some sort of abode, permanent or not, brick or wooden, somewhere nearby or along the edges of bodies of water everywhere.
Its a huge statement for habitat destruction, especially for fish, tropical or not.
See its one thing to like living near bodies of water but what we generally dont think about as well is the effect of having that abode near water.
I mean does anyone do some sort of study of how building
a house by the river or by the sea will result in habitat destruction of the fish in the water? Heck no! Thats probably the last thought in peoples minds.
Maybe in some European or American cities, there may be some laws to look at that but generally, not really.
So whats the problem you ask?
Well other than us humans not thinking about it, chances are those places are also the same places where fish breed.
If its not where they breed, it most definitely is where their nurseries are, where they grow up to become big fish that we need for our food or for the aquarium enthusiast to have in their aquariums.
Thats right, much of the nursery areas of fish, tropical or not, are along the coasts or along some stretch of land near water. Mangrove Forests, where the water is fresh and salty at the same time are important fish nursery areas in the tropics.
In the northern climes, these can be sea grass areas or places like fjords. So where we cause habitat destruction in such places, we also remove the places where the fish breed and grow up, and so presto! there is no more fish.
So that was just about normal individual houses. What about other man made structures then?
Docks, dockyards, ports or just a row of shops that put concrete on that piece of real estate? Think you get my drift, theres just massive habitat destruction going on along bodies of water everywhere.
I remember very well a place that I used to go with my cousins, really near to the town they were living in. It was just a short stretch of beach, an area with pure white sand and when the tide went out, there was a an adjacent muddy area.
You could literally go there whenever you liked and either dig up (very near to the top layer of the beach), tiny shellfish on the beach (Locally called 'Remis'. They basically look like small clams but with shells elongated like Mussels).
If you were slightly more adventurous, get yourself knee dip in the muddy area and go for the bigger clams that tend to be in such areas everywhere in the world.
Guess what? fast forward 20 years, there is no trace of that beach now :|
In front of it, there is now in fact a reclaimed island with a brand new dock and a large housing area to boot. The beach itself is now just another cemented area with a couple of shops and bars.
And that ladies and gents is probably the story of many a man-made structure we see anywhere now, anywhere in the world.
How could agriculture cause fish habitat destruction you ask,
doesnt seem to make sense right? Well its a huge problem, everywhere in the world.
A real good example is the association of the destruction of parts of the Great Barrier Reef due to excessive agricultural runoff from mainland Australia. Basically whats happening is excess fertilizer flows into rivers that eventually drain into the sea and ends up near the Great Barrier Reef.
This excess (which is a smorgasbord of chemicals yet again) causes imbalances in the water and essentially kills off the reef. Habitat destruction again, so a dead reef means no food and shelter for coral
fish, no fish means no predatory fish and so everything dies.
A lesser known situation is a bit north, not exactly tropical but a situation that may be repeated, albeit on a smaller scale anywhere in the world, that is the fate of the Aral Sea.
The Aral Sea was a huge body of water in the ex-Soviet Republics of
Kazakhstan and Uzbekistan. It had a thriving fishing industry,
industrial fishing boats were prevalent in this huge inland freshwater
Then, the Soviets decided to divert the 2 rivers that fed
this lake, the Amu Darya and the Syr Darya, to provide irrigation for
agriculture in the surrounding desert. Mostly for cotton but also for
The result was the lake shrunk significantly, causing salinity also to increase and so not only all the fish went, but basically all the original life. For a time they began to stock whatever water was left with sea fish.
The good story there is that at least part of this lake (a small part proportionately) is coming back with the recent building of a dam. Habitat destruction at its worse! (but an interesting case study
where a dam actually helps to bring back life rather than obstructing it).
Its not exactly habitat destruction but we might as well call it that since migration routes tend to be needed for spawning which means the creation of new fish.
If we block or remove that, we are causing habitat destruction. Of course the changing of the rivers rhythm by changing water flow, water speed and that type of thing is a form of habitat destruction too.
The famous related story is of course the Great Salmon runs of the Western Coast of the United States. There are untold number of dams all along the Salmon rivers, restricting their swim up to their spawning
The untold stories of various fish populations all over the tropic that rely on migration are suffering the same fate, albeit silently and without much understanding or knowledge from anybody.
A current topic of interest here is the planned damming of the Mekong River. As it is, a few dams are already in process upstream in China but several more are planned in Laos as well.
These dams will affect migration routes of many fish and therefore adversely affect the lives of millions of people downstream. This is quite a tinderbox of a topic.
A very famous lake in Malaysia was already affected by agriculture activities surrounding the lake.
Then in the name of tourism, a dam was created to 'increase the water level' of the river that fed it so that it would be 'easier to navigate into the lake' from this river.
Apparently the water level in the river gets pretty low during the dry season.
The result was that the water level of the lake itself changed, rising and lowering at odd times, causing the surrounding vegetation to die off, changing the water chemistry of the lake and causing untold havoc to the fish and other creatures in the lake.
Lets not even talk about the potential problem of the dam itself in terms of blocking any fish migrations. Thats the silly kind of habitat destruction for you.
So there you have it, all kinds of ways we as humans disrupt the places where fish live, breed and swim.
This is a harder topic. Whenever the situation is a 'human vs animal' situation, undoubtedly the animal always loses.
Some things that people are doing all over the world and have shown successes include:
1) Dismantling of dams! While the developing world (mostly in the tropics) are building dams and calling it 'green technology', the developed world like the US is slowly dismantling dams. This is especially true in cases where fish migration is known for those dammed rivers. Still a slow fight though.
2) Designation of 'No Fishing Zones'. I have already written about this under the overfishing section but it ties in to the topic of habitat destruction as well since the idea is that trawlers are also banned
from such locations.
Trawling tends to scrape every last thing off the sea floor and thus essentially destroying the habitat fish require. Its now being shown all over the world that having such zones not only allow for these areas to recover over several years but they also help to 'seed' surrounding areas and therefore allow for more fish catches for fishermen.
3) Creation of new habitats. This idea started many many years ago especially in terms of the creation of artificial reefs. It started with dumping unused tires into the seas, followed by cement balls and other
structures whereby providing corals places to hold on to and therefore creating new coral ecosystems.
There is even an innovative project out in Indonesia where they experiment using low voltage electricity to stimulate faster Coral growth (essentially having an electric cable from the land into the sea and attaching coral on metal fencing). They then transplant the corals to artificial reefs and again create habitat.
4) Recovery of old habitats. The idea of replanting mangrove areas with mangrove tree saplings and getting communities involved in the process.
I suppose this is probably more of an educational point, how can we make it humans 'living together with fish' rather than 'versus fish'. Education would be the best route to tackle this sort of thing so if you
dont know already, I am glad you read this far. So now you should go out and learn some more and spread the word around and maybe even get your toes wet as well (excuse the pun :) )