an example is the eastern scotian shelf ecosystem that suffered from overfishing of cod and other ground fish and consequently became dominated by crustacean and small planktivorous fish in the early s frank et al despite the ban on fishing since the ecosystem on the eastern scotian shelf has failed to recover to its former composition of fish thus both fisheries and climatic perturbations may have important consequences for the composition in ecosystems including the seabed community composition and biodiversity worm et al these losses occur at two levels depleted fish stocks imply that the cost of finding and catching the fish is higher that it needs to be and fleet overcapacity means that the economic benefits of fishing are dissipated due to redundant investment and operating costs the cumulative economic loss to the global economy over the last three decades associated with overfishing is estimated to be in the order of usd trillion fao a