For example, in a short period of time, the Orange Roughy became one of the most desirable fish in the sea. The industry was determined to meet the growing demand. After several years of intense fishing, the Orange Roughy is now nearly extinct. At the time, marine biologists had not discovered the fact that Orange Roughy can live to be 150 years old and are not able to reproduce until they are sexually mature at around age 30. Consequently, their populations were never able to rebound.
Today, the world is witnessing the devastating effects of the industry’s infinite greed, as they repeatedly destabilize and exploit every ocean on the planet. The term unsustainable can be defined as using or harvesting a resource in a manner that severely depletes or permanently damages the resource itself as well as other entities that are dependent on its stability. There are two factors that make commercial fishing unsustainable. The first factor to consider is the volume of fish who are killed.
In 2006, a team of researchers from the United States, Britain, Canada, Panama and Sweden compiled the most current and comprehensive report on commercial fishing in the world. They concluded that 29% of all commercially fished species are currently in a state of population collapse-defined as populations “at least 90% below their historic maximum catch levels.”  The United Nations Food and Agricultural Organization (FAO) cited similar findings in their 2008 report-stating that 80% of wild populations are either fully exploited, over exploited, depleted or recovering from depletion.  Driven by over fifty billion dollars in government subsidies, the number of fishing fleets in the world has increased to a point of saturation.
The second factor that makes commercial fishing unsustainable involves the techniques and common practices used to catch the fish.
Trawls are extremely large nets that are dragged through open water or along the sea floor. In the process, they indiscriminately capture any and all animals who are unable to escape through the small openings. They also decimate ancient coral communities that are home to thousands of plant and animal species.
Long lines consist of thousands of baited hooks hanging at varying depths over many miles. They are usually left in the water for long periods of time and kill many species.
Gill nets are large, nearly invisible nets designed to trap fish in the open water. After swimming into the net, the fish try to swim in reverse, causing their gills to become entangled. 
After becoming entangled in nets or impaled by hooks, the fish experience prolonged pain and suffering. They tirelessly try to free themselves and are vulnerable to predation and parasitism. The nets and hooks are reeled in at a fast rate, causing rupture of the eyes and swim bladder. Most of the fish die of suffocation in the minutes after being lifted from the water and dumped into the boat.
Each of the methods described above kill far more animals than the fish they target. Referred to as “by-catch,” these animals are of no value to the industry and are simply discarded. The FAO estimates the volume of by-catch to be about 20 million tons annually.  Turtles, birds and mammals drown after becoming entangled in the nets and hooks. Many of these animals have experienced a sharp decline in population-largely due to industrial fishing. According to the World Wildlife Fund, annual by-catch includes:
- Over 300,000 small whales, dolphins, and porpoises.
- Over 250,000 endangered loggerhead turtles and critically endangered leatherback turtles.
- 300,000 seabirds-including 26 species currently threatened with extinction.
- Billions of corals, sponges, starfish, and other invertebrates. 
 Retrieved 9/25/09 from http://www.washingtonpost.com/wp-dyn/content/article/2006/11/02/AR2006110200913.html
 Retrieved 9/27/09 from http://www.fao.org/fishery/sofia/en
 Retrieved 3/2/2013 from http://oceana.org/en/our-work/protect-marine-wildlife/sea-turtles/learn-act/fishing-gear
 Retrieved 3/2/2013 from http://worldwildlife.org/threats/bycatch