Such dramatic population plunges are not only dangerous for sharks but also for entire ecosystems. When shark populations decrease, a ripple effect can spread (pdf) throughout the rest of the ecosystem. For instance, the loss of the smooth hammerhead caused their prey, rays, to increase. The larger ray population now eats more scallops, clams, and other bivalves. This not only hurts the bivalve populations and therefore the biodiversity of the ecosystem; it also harms human fisheries. Furthermore, many coastal populations make money from the sharks that entice vacationers to their communities for ecotourism. One estimate for hammerhead sharks suggests that a live shark, over the course of its lifetime, is worth $1.6 million, which is a great deal higher than the $200 the dead shark can sell for. A recent study from the University of British Colombia projected that shark ecotourism will be worth more than the global shark fisheries in just a few years.