To many people, fish is a huge staple in their diets, so it goes to reason that we need large fisheries to provide this food to these people who depend on it. However, most large fisheries are not doing so in a responsible way. In 2009, Dr. Worm has stated that 80% of the global fisheries are at full capacity or completely overfishing and over exploiting the fish populations in which they fish. So logically, if we know that these large fisheries are over fishing, we know that this means that they are taking out more fish than that can be regenerated. This goes without saying that its only a matter of time before these fish populations die out, and if they die out, human populations cant eat the fish, and more importantly, it can destroy and entire ecosystem that relies on these fish as part of a system. However, this being the case, Dr. Worm said that it can be over comed by managing the populations responsibly, however, its an uphill battle because the fisheries will loose profits and the growing human population has a huge demand on these fish. Whats more, is not only are they catching eatable fish, they are also catching feeder food such as krill and anchovies in large amounts to feed farm breed salmon. The effect of this is that it is taking out a main food source for the fish in these areas. Its a huge problem for these fish populations to break even.
read more: http://www.globalissues.org/article/171/loss-of-biodiversity-and-extinctions#Dwindlingfishstocks