Mercury and heavy metals are being added to the oceans at alarming rates. Adding mercury to the ocean at even low concentrations has a massive effect on the final concentration of mercury in fish due to tropic feeding (food fed at regular amounts in regular intervals. Pregnant women or childbearing women should be especially careful of eating fish such as tuna, swordfish, and other species that may contain mercury or other contaminants.

Check out the Eco Friendly/Earth Friendly Seafood Guide to make both safe and ecologically responsible seafood choices.

With our technology, we can now fish anywhere, at any depth, and any species. But instead of large predators, we now focus on much smaller fish, which imbalances the food chain for the larger prey. Poorer countries rely almost entirely on fish to meet basic food needs, and because of our over-fishing, these countries are being seriously hurt with few alternatives for relief. All because of our greed for fish.

We now have a 90% decline in top predators. 75% of the ocean fisheries are either at their limits or are over-fished, yet the government uses taxpayer money to subsidize the fishing industry and build more fishing ships. On a global scale, these subsidies run up to $50 billion/yr, subsidies that are completely unnecessary.

Some birds and mammals that depend on fish have declined as over-fishing depletes their food source:

• • Off the Alaskan coast, Steller sea lions declined by 82% from 1960 to 1989.
• • In the Eastern Aleutian Islands, the count dropped from 50,000 to 3,000.

These declines are accelerating, with such creatures now considered endangered species.

Fish farming in fish pens causes an increased occurrence of contaminated seafood as they are all cramped together in a disease-ridden environment. Excretion and defecation by fish contained in shoreline pens add nitrogen and phosphorus to the ocean that stimulates the growth of phytoplankton, and eventually leads to anoxic (no oxygen) bottom waters.

The incidental damage caused by fishing is a substantial (and tragic) problem:

• Trawling & Dredging
  Bottom trawling and dredging are considered the most damaging. Nets with weights are dragged over the ocean floor, and over 70% of the catch is thrown back into the water (after it has been maimed, hurt, or destroyed). The amount of the ocean floor that is destroyed by trawling affects an area 150 times greater than the global area of forests cut down each year.
• Cyanide Fishing
  Cyanide fishing is a method of collecting live fish involving spraying a sodium cyanide mixture into coral reefs in order to stun the fish. The affected fish are incapacitated, some floating to the surface and some sinking to the bottom. Some of the ones scooped up survive the initial poisoning, while the rest die. The corals reefs themselves are also damaged. Almost 80% of marine aquarium fish sold internationally comes from the Philippines, most of which are caught using cyanide fishing.
• Dynamite Fishing
  Dynamite fishing destroys the coral and obliterates the fish. A single blast can destroy thousands of years of coral growth. It stuns, injures, and kills fish due to the immense pressure caused by the detonation. Some fish will float to the surface where they are scooped out.
• Longline Fishing
  Longline fishing has thousands of baited hooks stretching over 100 miles long. These lines are left in the ocean for 1-2 days. The hooks sometimes catch swordfish, tuna, sharks, sea birds (albatross diving for food), and turtles, that are thrown dead back into the water.
  • An estimated 180,000 birds die on longline hooks each year, some of which are endangered and nearing extinction.
  • 10% of the world’s endangered albatross population is killed each year by longlines.
  • Sharks have also been several impacted, with thousands killed each year by longline fisheries. Sharks have a slow growth and reproductive rate, which makes them particularly vulnerable.
• Chemical Runoff from Agriculture to Ocean (Dead Zones)
  Nitrogen fertilizer application has dramatically increased over the past 20 years with serious consequences as it enters streams, lakes, and coastal oceans. This increased load creates exceptionally large algae growth that eventually dies and sinks to the bottom of the ocean. It then becomes a food source for bacteria, which consumes the oxygen and creates near zero oxygen levels (hypoxic) or zero oxygen levels (anoxic) in the bottom waters. In these areas, a "dead zone" is created.
  
  Very large dead zones now exist as a result of fertilizer usage (e.g. the Gulf of Mexico). No organism requiring oxygen can survive in these zones.