A diversity of colorful, beautifully patterned species lives in tandem with coral reefs around the world, having adapted their appearance, body structure and lifestyle to take refuge in the folds of spiny, spongy, slippery reefs. Recent studies suggest that coral reefs, however, are just as dependent on these fish for key nutrients that help coral grow. When fish urinate, they release phosphorus into the water. This phosphorus, along with nitrogen excreted as ammonium through the gills of fish, is crucial to the survival and growth of coral reefs. A new study takes this a step further, finding that in coral reefs where fishing occurs, nearly half of these key nutrients are absent from the ecosystem. Paper co-authors surveyed 143 fish species at 110 sites across 43 Caribbean coral reefs that varied in the amount of fishing pressure sustained—ranging from marine preserves that banned all fishing to heavily fished reefs where large predator fish are almost gone. The researchers found that reefs with more large, predator fish had healthy levels of nutrients, while reefs depleted of large fish had nearly 50 percent fewer nutrients, including phosphorous and nitrogen, essential to their survival. http://phys.org/news/2016-08-big-fishand-peeare-key-coral.html
