MARINE DEBRIS - Marine Pollution: What Everyone Needs to Know - page 53

protected and endangered species. It is estimated that about
5,000 crab pots are lost annually from the Alaskan crab fishery
alone. Abandoned or lost fishing gear can be a navigation haz-
ard and have significant economic impacts. In a study of lost
gillnets in Puget Sound, Washington, scientists estimated the
daily catch rate of a single lost gillnet, which still catches crabs,
and developed a model to predict overall mortality. They cal-
culated that over 4,000 Dungeness crabs would be entangled
during the lifetime of a single derelict net, which is a loss of
over $19,000 to the fishery, compared to a cost of only $1,358 to
remove the net. Scientists recovered almost 32,000 derelict blue
crab pots from Chesapeake Bay that had trapped 40 differ-
ent species and over 31,000 organisms. Blue crabs themselves
were the most common species in lost pots with an estimated
900,000 killed each year, a potential annual loss to the fishery
of $300,000.
Entanglement of the monk seal in Hawaii, an endangered
species, is the major impediment to the species' recovery.
Monofilament line is single-strand, high-density nylon line on
fishing reels. Used line discarded into aquatic environments
can damage boat motors and wildlife. Marine animals can-
not see discarded monofilament line, so it is easy for them to
become entangled and starve, drown, or lose a limb. Illegal
driftnets in the Mediterranean Sea are a major hazard to
marine mammals, reptiles, and fish. The use of driftnets has
been banned by the UN for 20 years and the EU more recently,
but an estimated 500 vessels from Morocco, France, Italy,
Turkey, Algeria, and Tunisia continue to use them, inadver-
tently killing whales, dolphins, sharks, and sea turtles.
Australia is home to six of the world's seven threatened spe-
cies of marine turtles. During a recent cleanup of ghost nets on
beaches, 80% of the animals found in trapped in the nets were
marine turtles, including Olive Ridley, Hawksbill, Green, and
Flatback turtles. Getting tangled in ghost nets is one of the
most common causes of death for marine turtles in Australia.
Scientists used data on the number of ghost nets found during