While it may seem that there are plenty of fish in the sea, it's a different story just below the surface. Overfishing, lack of effective management and our own consumption habits are just a few factors contributing to a decline in wild fish.
Evidence of these problems abounds. Overfishing has resulted in nearly all commercial fish populations being well below natural levels. In just the past decade, Atlantic populations of halibut, bluefin tuna, swordfish, haddock and yellowtail flounder all joined this list of species at all-time lows. The cod fishery, once a backbone of the North Atlantic economy, collapsed completely in the early 1990s. The breeding population of Atlantic bluefin tuna has been declining steeply and may disappear completely in a few years without significant, immediate management changes. Other harmful effects of fishing—some of which are preventable with modifications to gear—impact the oceans, including the accidental catch of unwanted species (bycatch) and habitat damage from fishing gear.
How Did We Get Here?
One reason is the advent of industrial-scale fishing, which began in the late 1800s and has been accompanied by significant declines in the size and abundance of fish. By the 1980s, these fishing practices had made it impossible for natural fish stocks to keep up. Seventy percent of the world's fisheries are now exploited, overexploited or have collapsed. Meanwhile, demand has continued to rise, to about 110 tons in 2006—over eight times what it was in 1950. It's estimated that by 2030, the world will need an additional 37 million tons of farmed fish per year to maintain current levels of consumption.
Out of Sight, Out of Mind?
Because the oceans seem so vast and their resources limitless, these threats are often "out of sight, out of mind." But overfishing issues are not just for future generations to endure; they're very real problems threatening our current seafood supply and the health of our oceans. The good news is that there is much we can do—if we act now.
Learn which seafood to buy or avoid
You can also learn more about the Seafood Watch criteria for wild-caught seafood. 
Overfishing: Simply put, we're removing fish from the ocean faster than they can reproduce. More boats on the water and more effective fishing practices have worked together over the last 60 years to shift the advantage to fishermen. Decades of overfishing have driven fish populations to levels so low that recovery, when possible, is a long-term proposition.
Learn more about overfishing
Illegal fishing: Experts estimate that illegal, unreported or unregulated fishing—sometimes called pirate fishing—accounts for a quarter of the world's total catch of wild fish. Many fisheries that may otherwise be sustainable ignore and violate regulations, leading to overfishing.
Learn more about illegal fishing
Habitat damage: The habitat that fish need to survive can be destroyed by some types of fishing gear, for instance when large nets or trawls are dragged along the seafloor, sweeping up everything in their paths.
Learn more habitat damage
Bycatch: The process of bringing a fish to market can be messy. Large nets and longlines intended for one species often catch others by mistake. Fish, sea birds, turtles and marine mammals are included in this "bycatch," and are usually thrown back dead or dying.
Learn more about bycatch
Management: Worldwide, regulation of the fishing industry is weak, non-existent or not well-enforced. Rules intended to deal with overfishing, illegal fishing and the related issues of bycatch and habitat damage are ignored, and species like tuna that travel long distances are not managed consistently over their range.
Learn more about management