Discarded Gill Nets Dangerous To Ocean Life

Discarded Gill Nets Dangerous To Ocean Life

Gill Nets are a mesh net used to catch massive amounts of fish.  The size of the fish caught is determined by the size of the mesh openings.

Gill Nets are designed so that when the fish swims into the net, its head goes through the mesh hole and traps the fish.  When the fish tries to back out of the net, its fins are caught, thus holding the fish.

Gill Nets are made of multifilament nylon, monofilament or multimonofilament fibres.  They do not rot.

Ghost Fishing

When a gill net is lost or discarded by the fishers, it continues to fish.  This is called 'ghost fishing'.  As ocean debris,  the gill net entraps innocent turtles, sharks and even seabirds.

 Known as 'bycatch', the entrapped wildlife eventually dies.

Gill Net Facts

*  More whales, dolphins and porpoises die every year by getting entangled in fishing gear than from any other cause. Researchers at Duke University and the University of St. Andrews in Scotland estimate a global annual average of nearly 308,000 deaths per year - or nearly 1,000 per day. (1)

*  Because of their feeding behavior and their habit of overwintering in shallow waters, Loggerhead Turtles, together with Lepidochelys, is more prone to capture by shrimp trawlers and gillnets (mainly shark-nets). In recent years, in Atlantic waters of the USA, around 32,000 loggerheads were caught annually and nearly 21% of them died by drowning; in addition, more than 10,500 turtles were trapped annually in the Gulf of Mexico by the same types of gear, and approximately 29.8% of them were killed during trawling. The majority were late juveniles and subadults, while adults were relatively few. Also the records of the "Sea Turtle Stranding and Salvage Network" from the east coast of the USA show that loggerhead turtles were the most frequently stranded (73%) of the five Atlantic species, with a total of 2,373 individuals registered during 1987.

The blasting of old petroleum platforms is another cause of high sea-turtle mortality, especially of loggerheads. This kind of mortality is also reported for Mexico, Australia, South Africa, Japan, China, and wherever the loggerhead lives. The extent of the mortality needs to be evaluated in all these and other areas such as the Mediterranean Sea and the southern coast of the Arabian Peninsula. (2)

Seabirds are also caught in derelict gillnets.  They are attracted to fish and squid caught in the nets and dive several feet below the surface to get the fish.  Albatross, Northern Fulmars and Shearwaters are known to regularly get fish this way.  Many times the seabirds are trapped in the nets.  The mortality rate is huge. (3)

Sources:

(1)  CetaceanByCatch.org

(2) FAO.org

(3) EarthTrust.org

Resources: 

 United Nations Fisheries & Aquaculture Dept.

Seawatch.org

Ocean Studies Board of the National Academies