Vinegar Proves to be Solution for Crown Of Thorns Starfish

The crown-of-thorns starfish has long since been a problem for the Great Barrier Reef, and has posed a problem for marine biologists and conservationists for many years.

The crown-of-thorns is an invasive species that is considered to be one of the biggest threats to the Great Barrier Reef and has been on the rise in recent years. The Great Barrier Reef Marine Park Authority (GBRMPA) states that it is known for outbreaks about every 17 years, which the latest starting in 2010.

As the crown-of-thorns feeds on corals, when it becomes too populous it poses a problem to the overall health of the reef. Normally, a reef is considered healthy if one crown-of-thorns is recorded during a 20 minute swim. However, when it gets to a point when the crown-of-thorns is more populous, or 15 or more are recorded per hectare, and consuming corals faster than they can they can grow, you see a decline in coral cover and an increase in crown-of-thorns numbers, which is when population control comes in.

In the past years, there have been several methods used in an attempt to control crown-of-thorns outbreaks. These include injecting them with compressed air, taking them ashore and baking or burying them, injecting them with toxins (bad for the reef), injecting them with sodium bisulphate (not bad for the reef) and building underwater fences to control their movement. Early reports talk about how originally divers use to chum them up, cutting them into many pieces, thinking they were killing the starfish. Little did they know this species easily regenerates from each discarded part, creating many, many more starfish. They have since stopped the practice and have moved to more humane and effective methods.

The most recent development in the crown-of-thorns problem is a lot simpler than you’d think: plain vinegar. Household vinegar has been proven to be an effective solution to the problem, and a cheaper one at that. Researchers are using the same methods as before and injecting the crown-of-thorns starfish, but now with a much simpler solution that costs less and does not harm the surrounding reef. The single 20ml injection works by infecting the echinoderms which die and disintegrate. Starfish are unable to regulate their internal pH levels, so the vinegar, which is extremely acidic, proves lethal. And the price? About one cent per dose.

It should be noted that the crown-of-thorns normally plays an important role to the reef. It is a native species to the Indo-Pacific region, and on a healthy reef, plays a vital to the overall health of its ecosystem. In a healthy reef, the crown-of-thorns feeds on fast growing corals, leveling out the playing field and allowing slower growing corals to grow instead. This stops any one species from drowning out another and increased coral diversity, and increases the health of the reef.