Report - Crown of Thorn clean up campaign West Efate, Sunday 18th November
Sunday 18 November: COTs - N.W. Efate Frontal line Report #2
Last Sunday we had 6 divers in the water doing 2 dives each, comprising 2 staff from Big Blue Dive, a Pele Island diver, French & Aussi volunteers and 1 x Sailaway diver.
We concentrated on the area found last week between Paul's Rock and the coastline, between 8 - 15 m depths, and up to 150 m offshore. We found some aggregations where they were really thick on the ground, with many in hiding during daylight hours under shelves or plate corals.
First dive at: Lat 17 deg 39.91 min; Long 168 deg 11 min, we collected 286 COTs in 22 flour bags. Lunch and a 2 hour surface interval followed.
Second dive at: 17 deg 39.88 min; 168 deg 10.99 min, we collected 338 COTs in 26 flour bags. Total for the day = approx 620 COTs, which were taken ashore.
So, in 2 working days we have removed over 1000 COTs , such that an area of 200m radius is now almost clear.
Our radius at this second anchorage extended out 150 metres and it could be seen the Frontal Line had moved further Northeast and in 15 m depths could in fact be closer to Mangaliliu Village than we previously thought, even though snorkelling on the fringing reefs out from the Survivor Beaches shows no sign of COTs as yet.
Next Sunday, we shall move our anchorage further NorEast to better define the Frontal Line and then work back from there to SouthWest.
Any volunteers are welcome to join us. We look to be making a difference, but realise the effort must be continued well into the future, to be effective.
Interestingly, Big Blue Dive have noticed that in areas of Mele Bay which had heavy concentrations of COTs say 2 years ago, that there is now an increase in opportunistic Drupella sea-snails which move in after a COTs outbreak and mop up any remaining live corals. In the past 30 years, we have never had a problem with snails on Vanuatu reefs, although on the GBR Drupella snails had been a big concern to Reef Check (& possibly still are?)
We are still not sure what chemical would be most cost effective to kill spawn-water collected in the bilge of the dinghy, but expect Ammonia or Bleach would be suitable as it can be injected into COTs to kill them, and the NH3 is environmentally friendly, breaking down into salts in seawater.
Cheers, Peter @ Sailaway.
Tel: 23802; 7723802