Sharks; 'Heading for Troubled Waters'

In today's newspaper, there was an article titled "Heading for Troubled Water", a study done by Dal Housie and the depletion on the worlds sharks. Many of the worlds sharks are near extinction and it is thought that this extinction is causing a serious/dangerous ripple effect in the marine food-chain. A study has been done, and it shows that there is a disappearance to depletion of other marine species. The species that sharks use to prey upon are now having a huge boom since there is not as many sharks around to prey on them.It has been shown that there is an increase in about a dozen smaller sharks, rays and skates and this has caused a cascading effect throughout various ecosystems because they are depleting the limited amount of nutrient sources, which is altering natures complex food webs. It is thought that since the larger animals are being disproportionately hit by overfishing, that it is effecting everything beneath them in the food web. This is restructuring the oceans food web and how it operates.
Scientists are now thinking that the shark populations are lower then what was previously thought. One of the main sources for this huge decline is the practice of finning the sharks then throwing the carcasses back overboard. Since there is such a huge decline in the top predators, there are not enough of them around to be fulfilling their roles in the food web and therefor no longer controlling the species below them. Not only is this having effects in the oceans, but it is having effects for communities that depend/thrive on healthy fisheries. Scientists are not yet sure of what this means for the oceans food web, but they do think that the greater increase in other species will disrupt the wider natural order in all the oceans world wide. It is estimated that the population of the rays alone has increased about ten percent.
Scientists only thought that this could happen in smaller ecosystems like ponds, but seeing it in the marine environments has become very alarming. Scientists are now seeing why one species, like the sharks, can be so important to the entire world and how it can disrupt the flow of energy.
Now that scientists know, they should be spreading the word around and start enforcing laws so that the populations in the oceans can get back to normal and their is not a mass extinction like what happened with the dinosaurs.
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~ http://thechronicleherald.ca/NovaScotia/567675.html