Poor knowledge of the numbers of many animals in the Galapagos Islands will make the long term impact of the fuel spill very difficult to assess, says a British expert. He adds that damage to animal populations could be worse than expected because they are still recovering from the effects of the 1998 El Ni帽o.
On Thursday, winds were continuing to blow the spill away from the archipelago. But heavy 鈥榖unker鈥� fuel has been washed on to the shores of three islands.
All the invertebrates around the grounded tanker, the Jessica, are dead, and birds and sea lion colonies are at risk. But animals that feed in the inter-tidal zone, such as marine iguanas, will be particularly vulnerable, says Ken Collins of the Southampton Oceanography Centre, who has been mapping marine biodiversity in the islands.
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鈥淭he bigger iguanas will be able to dive and get below the waves for food. But the smaller ones feed in the inter-tidal zone, where oil has been deposited. In some areas, you could see a wipe out of one year鈥檚 reproduction, and the poor creatures are still reeling from the effects of the El Ni帽o,鈥� Collins told 快猫短视频.
Exactly what proportion of the Galapagos鈥檚 marine iguanas died as a result of the El Ni帽o 鈥� and how many will die as a result of the spill 鈥� is almost impossible to estimate, says Collins.
鈥淭here are decent censuses for certain animals in certain sites. But, although the Galapagos is not big, it鈥檚 got a terribly frilly coastline,鈥� he says, making it very difficult for researchers to get around. 鈥淣o one knows the numbers of sea lions, iguanas, or many other species.鈥�
The El Ni帽o caused algae, the bottom of the food chain, to blow away from the islands, causing a mass starvation of marine iguanas, crabs and other animals.
The fuel, which started leaking from a grounded tanker on January 18, will kill in two ways, says Collins. It will kill the vital algae, mainly by blocking sunlight and oxygen from the water, and it will also kill directly, if ingested.
鈥淭here鈥檚 no way they can prevent it coming ashore because the coastline is so knobbly,鈥� he says. 鈥淭he bottom line is this spill is going to break up and come ashore in drips and drabs. We won鈥檛 get mass extinctions, because the effects will be patchy. But there will be localised wiping out of algae and animal deaths.鈥�
Much of the research on marine animals in the Galapagos Islands is to assess the potential for commercial fishing, says Collins. This research will be useful in helping to assess the spill鈥檚 impact.
鈥淭here has been a lot of effort devoted to trying to get censuses of populations in fished and non-fished areas, to come up with suitable quotas,鈥� he says. 鈥淭he big hope was that sea urchins could be profitably fished. As it happens, that sort of data is from impacted areas and will be incredibly useful.鈥�
The Jessica ran aground less than one kilometre from San Cristobal island. It is thought the captain mistook a signal buoy for a lighthouse. On Wednesday, the captain and crew were arrested. They have not yet been charged, but if convicted of negligence or crimes against the environment, they could face prison sentences of up to four years.