Many shark species are referred to as apex predators, meaning that they are at the top of a food chain. The importance of sharks as apex predators cannot be overstated. With the decline or extinction of shark species that have existed for millions of years, the delicate balance of aquatic ecosystems could be thrown into chaos. Many scientists theorize a 'top-down' effect, in which each subsequent species on the food chain would affect the one below it. Like an aquatic version of falling dominoes, extinction of shark species would cause an explosion of seals and other shark prey species, which would cause a severe reduction in fish preyed upon by seals. This top-down shift would continue to affect species down to the smallest creatures in the ecosystem, such as zooplankton. Therefore, the most important beneficial trait in sharks is simply their existence.
As well as being apex predators, sharks also have non-predatory symbiotic relationships with other species in their ecosystems. A symbiotic relationship occurs between two different species in which each benefits from the presence of the other. The symbiotic relationship between sharks and remoras and other cleaner fish is mutually beneficial in the way that the cleaner fish gains nutrition from the parasitic animals on the skin of some shark species, while the shark benefits from the removal of the parasites.
Shark ecotourism, like whale watching before it, is an industry that is beneficial to sharks as well as humans. More and more, shark diving tours have begun appearing all over the globe, offering tourists a chance to swim with these beautiful creatures. Increased shark tourism not only boosts coastal economies, but also shifts the focus from charter fishing of these animals to observing them in their natural environment. It has been estimated that shark diving has contributed millions of dollars to economies like Palau. As a result, the life of just one shark could potentially be worth millions of dollars.
The study of the unique skin of sharks has enhanced technologies in naval engineering. Because the skin of some shark species resist parasitical accumulation, such as barnacles and algae, scientists have developed a surface coating for sea-going vessels that mimic the properties of shark skin. The impact of this development is both enormous and far-reaching. The shark skin coating applied to the boats will prohibit the presence of parasites and in turn will lessen drag and make the vessel more energy efficient. When applied to naval ships it eliminates the need to remove vessels from the water to remove parasites. With a ship as large as an aircraft carrier, the cost of removal and cleaning of just one carrier numbers in the millions.