Many fish species get shelter and protection from coral reefs, as a return to which fish offer urine to the ecosystem.

A latest research, which appeared in the journal Nature Communications, disclosed that inadequate fish urine is responsible for the insufficient nutrients around corals in waters where occurrence of commercial fishing usually takes place.

Typically, fish take shelter in and around corals in the daytime and urinate vital nutrients. During night they find food in and around the reef.

As a result of this setup, both fish and corals get benefits. On peeing, fish discharge phosphorus and nitrogen in ammonium form via their gills, serving as significant nutrients for growth of coral reefs.

Coral reefs’ health and growth are affected by any change in the level of nutrients. A previous study has demonstrated that growth of coral reefs with healthy fish populations is faster in comparison to the ones having smaller fish population.

Jacob Allgeier, study researcher from the University of Washington's School of Aquatic and Fishery Sciences, mentioned about the significance of animals in coral reefs, as they help in the movement of the nutrients around.

Fish possess a huge part of the nutrients in a coral reef in their tissues, thus they also play a significant role in their recycling. It means removal of fishes also removes nutrients from the ecosystem.

Allgeier said, “Simply stated, fish biomass in coral reefs is being reduced by fishing pressure. If biomass is shrinking, there are fewer fish to pee”.

During the research, Allgeier along with his colleagues calculated the nutrient levels at different corals reefs and discovered that the level of important nutrients was more in reefs having greater predatory fish population, while the reefs with only some huge fishes possessed poor nutrient levels.

According to a report in Tech Times by Rhodi Lee, "The setup offers mutual benefit for both fish and corals. When fish pee, they release phosphorus and nitrogen in the form of ammonium through their gills, which serve as important nutrients for coral reefs to grow."

For the new research, Allgeier and colleagues measured the nutrient levels at various corals reefs and found that the level of vital nutrients is higher in reefs with greater population of predatory fish, while the reefs with few big fishes have poor nutrient levels.

"We suggest that in addition to well-acknowledged conservation targets such as biodiversity protection, a broader perspective that incorporates predictable impacts of fishing pressure on nutrient dynamics is imperative for effective coral reef conservation and management," the researchers wrote in their study, which was published on Aug. 16.

A report published in Washington informed, "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."

“Fish hold a large proportion, if not most of the nutrients in a coral reef in their tissue, and they’re also in charge of recycling them. If you take the big fish out, you’re removing all of those nutrients from the ecosystem.”

The researchers determined that, despite the substantial reduction in fish-mediated nutrients, fishing didn’t substantially reduce the number of fish species present. Instead, the large reductions in fish pee were driven by the reduction of large-bodied fish and predator fish such as grouper, snapper or barracuda that occurs through selective fishing practices.