Research conducted by the Arizona State University in conjunction with the University of Leeds had recorded an alarming decline of fish biomass of 45% within the their surveying period. This is a significant concern as these fish play vital ecosystem services for tropical coral reefs which form a mutualistic relationship.
Herbivorous fish are important in the maintenance of our coral reefs where for example the parrot-fish use their beak-like jaw to scrape clean the substratum of the corals providing new sites and exposing this coral substratum suitable for coral settlement and to recover from coral bleaching.
Grazers play a vital role in keeping the coral turf abundance in control which show little environmental importance and if provided with adequate levels of nutrients the turf coral will outcompete all other vegetation. An issue that had been identified in the west of Hawaii by the University of Leeds had realized that nitrogen effluent originating from sewage had put a strain onto the coral and fish populations because of the excess nutrient levels in the water. This causes domination of turf coral eliminating large quantities of other coral species. Due to high abundances of these turf corals will increase fertility rates of large grazers and predators due to less strain put onto these populations, however, due to a lack of corals (shelter, nursery etc) as well to such a high predator causes smaller fish populations will plummet. These large grazers and apex predators have very few natural predators and are classified as a type 1 on the survivorship curve. This then will result in a reduction in energy transfer between the trophic levels because most of the energy is consumed by the fish and there is little natural death and organic material which will further reduce coral populations.
These coral reefs are so integral component of the oceans as they provide the aquatic systems with a diverse genetic library. Without the maintenance of these ecosystems it would be likely that generalist species would dominate causing a lower genetic diversity library which will make it more difficult for these species to adapt to environmental change.
Coral reefs are also responsible in dispating 97% of the wind energy that would otherwise smash off the coastline. With the extreme climates predicted with climate change will cause significant damage to ecosystems in the coastline and only grasslands would likely survive. It is likely that countries like Ireland would suffer from the destruction of life and erosion of the coastlines.
