A marine biologist from the University of North Carolina published a research that brings bad news. We all know that coral populations are in danger and their numbers have been alarmingly decreasing. It appears that the predators in the Caribbean have no better fate than corals.
John Bruno is the marine biologist that noticed the absence of the predators that once were flourishing around coral reefs. Sharks, barracudas, grouper, or other big fish that used to roam the reefs are now mostly gone.
This is why he decided to start his research and discovered that up 90 percent of the predators in the Caribbean disappeared because of overfishing. Coral reefs no longer have big species to prey around and this can have huge consequences on the ecosystem.
Bruno explained that the absence of any predators can have the same effects on the coral ecosystem that the disappearance of wolves had in forests. If predators are gone, their prey can eat freely from the grass (or coral, respectively). Thus, the ecosystem is no longer in balance and the habitat of smaller species is affected.
For instance, when a crippling disease massively reduced the numbers of sea stars, their prey sea urchins reproduced too quickly and caused smaller fish to lose their hiding places. Also, since they reached such high numbers, sea urchins ended up starving.
Besides the ecological value, sharks also have a touristic value. The Caribbean islands gather thousands of tourists that come every year for snorkeling and watching of sharks. Only one live shark is worth around one million dollars in revenue.
Thus, John Bruno, together with researchers Abel Valdivia and Courtney Cox, decided to begin their study in an extreme way. They went to visit 39 reefs around Mexico, Belize, Bahamas, Cuba, and Florida, submerged into water and started counting the predators that circled them.
They compared the numbers recorded in reefs full of life to the typical reefs. This is how they discovered that almost 90 percent of predators have vanished, and they suspect the main cause is overfishing.
One reef that flourished with life was situated off the Cuban coast, Jardines de la Reina. They explained that fishing usually took place off the coast of the main island, and those people who reached the area of the reef were usually trying to escape to Florida.
The researchers stressed the idea that these reefs should be protected and fishing should be limited. At such rates, there is a risk that predators should disappear completely if we do not take action.
Image Source: Wikimedia Commons