2014 Escapade jumps aboard the Vanuatu Crown of Thorns Starfish Control Programme
Crown of Thorns Starfish are a problem across many coral reefs in the South and North Pacicifc oceans. Whilst in Vanuatu, race entrant Escapade, will be doing some volunteer work to assist the programme by providing sighting information to help control the outbreaks.
How Cruising Yachties could Assist with Vanuatu's COTs Control Program:
The Crown of Thorns Starfish (COTs) is eating out coral reefs right across the South & North Pacific oceans, from the Cook Islands to the Great Barrier Reef (GBR). Vanuatu has also seen infestations in different areas, usually starting around areas of mankind habitation causing: effluent outflow; over-fishing; logging or large scale agricultural usage: or following large port dredgings or massive cyclone damage to reefs. ie: where the immune system of the oceans has been compromised by mankind or nature in some way. Small numbers of COTs in such areas take the advantage of spawning millions of eggs and the subsequent larvae are not being eaten by the weakened, unhealthy corals or a depleted fish population. Once an aggregation is underway, it is most difficult to stop and several generations of Starfish could remain in an area for 10 or so years, reducing the coral cover dramatically and thus affecting the whole marine food chain. The GBR has lost half its coral cover in just the last 30 years. Likewise for Vanuatu, partially due to cyclones but more recently due to COTs.
Since 2005, Scuba Operators and village communities have been active in culling COTs infestations, especially where they impact on healthy reefs which visiting Tourists wish to see on snorkelling or scuba diving tours.
We have developed several COTs-culling techniques, depending on whether they are used by snorkellers or divers at different depths.
The hook and flourbag technique is useful for divers or snorkellers to gently hook the COT from under corals and feed them into the flour bag which can take about 12 large ones, or 20 smaller ones, before tying off the drawstring at the top and leaving the bag in the water for 1 day. The COTs require water flow over their bodies to absorb life-giving oxygen. So, inside a bag they quickly die from oxygen deprivation, as do any spawn released during their dying moments. The next day the COTs can be released from the bags for fish to eat.
For very large aggregations, where the COTs are roaming the reefs by day or night, GBR scientists have developed a *one shot* injection system, using acidic chemicals which kill the COT within one day, due to changing the internal pH value of the COT. Ox-bile-salts are the most recent injection liquid used on the GBR, but this is difficult to obtain in Vanuatu. French scientists have come up with an alternative which is equally effective, cheap to obtain and which doesn't affect other marine life nearby.
How can visiting cruising yachties help in this COTs control initiative?
The Department of Fisheries is setting up a Database of COTs sightings throughout the islands of Vanuatu. If yachties are sailing around the islands and doing some snorkelling here and there, if they see signs of actual COTs or white coral skeletons which indicate COTs have fed there in the past week, then this information could be passed on to a Database within a new Fisheries website being constructed.
Info needed, includes Position (Lat & Long or which Island and closest village); Depth seen in; Size range of the COTs measured across the flattened critter; How many seen per 50m x 50 m square; were they on coral rubble or healthy, colourful reef? Hiding under corals or openly feeding on the top of reefs?
The idea is to determine where the COTs are at present, what sizes, and in what quantities. We could then target COTs-SWAT teams to go in and significantly reduce numbers before the next spawning season, Oct - Feb.
We can't hope to protect all the islands, but Tourism-sensitive or especially healthy reefs could be protected by active cullings by villagers, scuba operators and possibly yachties, especially those with scuba facilities.
The Vanuatu Tourism Office is currently having a Yachties' microsite compiled by Kiwi yachties, the aim of which is to provide useful info for incoming yachts, including a list and details of cultural events planned for each year in the outer islands. We also expect to have a segment in the website, whereby yachties can send COTs sightings & relevant details, directly to the Fisheries database.
At the moment (early May 2014), we have a secondary outbreak about to begin on Emao Island, North Efate Is. and some residual mopping up to do on Moso Island.
But major infestations were seen in 2013 in the Maskelyne Islands, Southwest Bay on Malekula Is. and likely travelling up the West coast of Malekula and emerging at the offshore islands of South Espiritu Santo. eg; Aore, Malo, Bokissa and moving up the East coast of Santo.
During the winter months, the COTs are mainly in hiding by day and don't eat too much by night. But as the spawning season approaches and the tradewinds drop, seas calm down and warm up, the COTs put out pheromones (chemicals) which alert other COTs in surrounding areas to aggregate together to increase chances of fertilisation of the millions of eggs released. Only about 10% of eggs are thought to be fertilised and of those larvae so produced, probably only 10% survive predation by healthy corals and fishlife. Many more larvae survive if the reef systems have been degraded by previous outbreaks. The larvae eat algae and nest in the coral rubble for about 18 months before emerging as juveniles to start consuming the coral polyps of healthy plate or staghorn or scelecterian corals. And so the cycle continues until there is virtually no live coral left.
Extreme care must be taken in handling COTs, as their spines are poison-tipped. You really do not want to get pricked. It is very painful. Hot water and bleach can neutralise the poison, but the sharp spine-tip breaks off under the skin and can fester if not removed early on. Hence, use of gloves is recommended and people who are a bit clumsy underwater should not even attempt to collect COTs by snorkelling or diving.
|Mama and juvenile COTs, showing 50cm long hook-stick used to remove them from coral.|
|COTs often hide under corals by day, but are nocturnal and roam the reefs by night to feed.|
Around 16 legs and hundreds of suction-pad tube-feet allow the COTs to climb anywhere. Stomach is extruded through the central hole, overlaying the coral and absorbing the polyps.
|As the COT is removed from the coral, it curls up to protect its undersides and can then be slipped into a flour bag, which would take 12 large ones like this.|
|When full, the bag is tied off and left in the water for one day, after which the COTs have died from lack of oxygen. Bags are then emptied and fish eat the freshly-dead COTs from the underside.|
|Approaching the spawning season, the COTs aggregate in a *love-fest* to increase chances of fertilisation of millions of eggs ....|
|A typical COTs-SWAT team with hooks, gloves and bags, geared-up for a culling session.|
|New system for large aggregations = simple plastic sheep drench gun, with nozzle & needle attached. Use I.V. Drip Bag or larger squeezable bottle in BCD pocket. Blue dye (as an indicator) is mixed with chemical.
The COT is held down firmly by the hook-stick, whilst 2 or 3 injections of 5ml are made, equi-spaced into the *shoulders* (upper base of arms).