Ship Groundings Crush Coral Reefs

Ship groundings, instances when boats crash into and get stuck on coral reefs, are dangerous both to the ships’ passengers and to coral reefs.

A ship grounded on a coral reef. Photo Courtesy of JustinIs/Flickr.

Groundings sometimes occur as a result forces beyond human control, such as stronger-than-predicted tides, but they also occur as a result of carelessness and human error. Given the abundance of sea-faring navigation technology and maritime traffic regulation that exists today, groundings are one threat to coral reefs that can be prevented.  On a basic level, ship groundings harm coral reefs because they physically break or crush them. However, groundings can also have less obvious, residual impacts on the health of coral reefs.

In April of 2010, a large Chinese ship carrying coal became grounded on Australia’s Great Barrier Reef.  According to Maria Kamenev, for a TIME magazine article entitled “Grounded Ships Not Great Barrier Reef’s Only Threat,” the enormous vessel “plowed at full speed” into a pristine, protected area of the the Great Barrier Reef. The ship utterly demolished a chunk of the Douglas Shoal at the Great Barrier Reef Marine Park equivalent in area to the size of five football fields.   The result was “ a vast, empty plain of sand where a healthy coral community had hosted a variety of unique plants and animals.”

To further the tragedy, the ship, which left a 3,000 m by 260 meter “scar” in the reef, was carrying 65,000 tons of coal and 950 tons of fuel oil. According to Kamenev’s article, the equivalent of 2,000 to 5,000 liters of heavy fuel oil seeped into the water with the collision.  For video coverage, and more information on this grounding, see the video below.

Sadly, vessel groundings of ships carrying fuels and other toxic materials continue to occur. Often times, these instances are the result of human error, and could have been prevented.  According to Kamenev, The Great Barrier Reef suffered three major groundings in 2010. In the case of the grounding at the Douglas Shoal, it was reported that the ship’s captain “had only 2½ hours of broken sleep over the 37-hour period before the crash.”

Damage sustained by coral reefs as a result of ship groundings is not limited to physical crushing of the reef structure.  Added risks come from materials that leak into the sea upon grounding.  One of these materials is a type of paint often used on the hulls of ships. When shipping vessels crash into reefs, heavy metals and other toxins are often left behind.  This can lead to further damage to the coral that actually survives the initial impact of the grounding.

In their article, “Understanding ship-grounding impacts on a coral reef: potential effects of anti-foulant paint contamination on coral recruitment” Negri, et. al, write, based on a case study of a grounding on a reef off of Malaysia, that “The recovery of reefs from ship-groundings is often very slow and in many cases may take decades (Precht, 1998).”  They argue that “apart from acute and chronic toxicity towards sessile adult invertebrates such as corals, anti-foulant contamination has the potential to impact on the recruitment of invertebrates to the damaged site, therefore slowing subsequent ecosystem recovery.”  Thus, the impacts of ship groundings on coral reefs seem to be greater than the immeditate damage sustained given that contaiments from anti-foulant paints can slow the recovery of the reef.

Small vessel groundings can also cause physical damage to reefs. It doesn’t take an oil tanker to physically damage a coral reef. Coral reefs are so delicate that even small boats can crush and seriously damage coral colonies.  Recreational and professional boaters alike should take care to stay in marked channels, pay attention to maritime regulations, and treat the process of captaining a boat as seriously as one would treat driving any other type of vehicle.