Dead fish laying in Philipsburg Great Salt Pond – Photo TSXM Milton Pieters
TSXM – GREAT BAY – Water quality tests were carried out by the nature Foundation in the Great Salt Pond from August 7 until August 12 in order to determine levels of pollution associated with the current fish die offs, in order to determine the level of its water quality.
Tests were carried out in order to determine Nitrate, Phosphate, Nitrogen, Dissolved Oxygen, Coliform Bacteria and pH levels. Tests were carried out using both Akton Water Quality Testing Strips and the Lamotte Water Pollution Kit.
Since July, the island has been experiencing little rainfall and on occasion calm weather. This, together with land reclamation activities in the Great Salt and Fresh Ponds has resulted in poor water circulation and a drop in dissolved oxygen (DO) levels in the ponds. The drop in DO has resulted in oxygen depleted water (a DO level close to 1 part per million is essential oxygen depleted compared to a normal level of 7 ppm) which in turn results in fish die offs. The worry is that Tilapia will be the first species to die, followed by Tarpon, Mullets and other native fish species.
Tilapia fish are an introduced species in St. Maarten, having established themselves over the last 10 to 15 years in the Great Salt and Fresh Ponds. The presence of Tilapia has to be closely studies for the effects on the native fish population, however the die-offs of a tolerant species such as Tilapia has to raise concerns about the water quality of St. Maarten.
The Nature Foundation has relocated approximately 300 tilapia from the Great Salt Pond into the Fresh Pond were oxygen levels are greater, however with the continuous hot weather these fish are also in danger of becoming threatened.
The foundation would like to echo government’s advice not to eat the fish; doing so might have some significant health consequences.
The Nature Foundation would also like to urge the public to take the necessary precautions and prepare to deal with an unpleasant smell in the Great Bay area. Although the fish are being cleaned there is a risk of a bad smell and also an increase in flies.
The Nature Foundation recommends that the levels of the ponds be continuously managed in order to reflect meteorological conditions in order to avoid further die offs.
The foundation will monitor the situation closely as they continue.