So just what is the plankton bloom all about?It is the accumulation of algae/phytoplankton in a water system.Many factors induce this rapid increase of the microscopic organisms.but it all leads down to the basic 4 requirements of algae; Sunlight,warm temperatures and availability of oxygen as well as a high concentration of nitrates.
As a fisherman and a fellow environmental and aquarium enthusiast I'm here to represent my views of the current situation that has caused a devastation and a mass killing of hundreds of fishes primarily in the eastern parts of Singapore(Sembawang,West coast,Woodlands not as affected).This has definitely caused a halt to all fishing activities for us Saltwater anglers.
There was a video that featured the chairman of aquaculture of Singapore, Philip Lim,being interview in regards to the situation that fish farmers were facing out at sea to sustain a healthy livestock.
He had mentioned several good points such as landfill and dredging works done by the various environmental agencies( to ensure that sand erosion was prevented) which played a role in water pollution.also there was lots of ranting on how AVA was not playing a part in ensuring that the algae bloom was controlled or prevented altogether.
He stated that the kelongs were sustaining the ecology and that the environmental agencies weren't.I see many issues with this one sided argument and began to form my own views about this matter.
It takes 2 hands to clap and definitely both are at fault which had inevitably started all this.
So I'm here to list down 4 reasons on how the surrounding kelongs had played a part to cause this catastrophy as well.
1) Harvesting of shellfish
on a large scale.Every week we go out to sea and realise that the mussels along the barrels at Pasir Ris seem to have been scraped off.rocks are often wiped clean of any form of shellfish as well.how is there a link to any of this?Shellfish are filter feeders and are known to be introduced in certain countries to relieve the plankton population in water bodies.the consume large amounts of plankton an other substances such as heavy metals.they are known to be voracious filter feeders which can wipe clean an aquarium if introduced.A drastic reduction of them was seen throughout the days counting down to the bloom.
2)Harvesting of crustaceans
harvesting of crustaceans such as crabs and prawns from the sea.I've been told by many that kelongs are responsible for the drastic removal of these scavenges of the sea bed with an average haul of 5kg on a bad day to 8kg on a good day.what does that equate to?a build up in dead matter on the sea bed.which leads up to a concentration of ammonia and nitrites in the water.the same components that encourage algae growth in many aquariums.We learn from aquarium keeping that nitrates are eventually removed with consistant water changes.though it is true that the sea easily replenishes itself in an instant,this is not the case of Pasir Ris which is known to have a slow undercurrent and a poor exchange of water during the low and high tide.this would also explain why Pasir Ris was hit the hardest.
3)Drift Netting
drift nets are used by kelongs excessively to bring up wild caught fishes such as snappers,barramundi,breams and feeder fish which are lucrative in the market. It is also the cheapest method of obtaining food for their livestock. Bycatch is always an issue with this method of fishing as undesirable fishes are tossed back into the ocean with a 10%-20% survival rate after being trapped in the nets for a long time as well as being in the nets on board the farms for a long duration.this adds to the loss in biodiversity in the waters.feeder fishes are also reduced significantly from the environment which leads to a reduction in the bigger sized fishes.Net are everywhere in the east.places which are permitted and even some which aren't which challenges the integrity of some farmers.they stretch as fair as a 100M and trap anything in it's path.
4)The Structure Itself
Kelongs hold up to a few hundred fishes at a time as most of you saw the video of the dead fishes floating in the containment nets.what does this mean?a concentration of fish waste.Fishes with big appetites and even bigger waste.this concentration of waste helps promote algae growth with a combination of Singapore's humid weather it is a recipe for disaster.
but they've been doing this trait for such a long time so how does this make sense?the sudden increase in the amount of kelongs in Singapore's waters especially around Ubin and Pasir Ris.a few years ago there weren't as many of them as there were lets face it.This year was one of the worst blooms ever.However it might just be a coincidence. I grew up in Pasir Ris and kelongs were quite an interesting sight which has now become an anglers most hated thing.more kelongs means more netting therefore there is almost nothing significant that ventures near to shore(in terms of fishes)
thanks for taking the time to read this post!once again these are just personal opinions!
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