Negative effects of commercial shrimping and fishing on sea turtles - Final

This discussion topic submitted by Maura McCarthy (mauramc@hotmail.com) at 2:18 pm on 7/28/99. Additions were last made on Wednesday, May 7, 2014.


I. Introduction

A. Fishing is the most important source of human-associated mortality to all four protected species of sea turtles occurring of the U.S. Atlantic and Gulf Coasts.


1. The four species include the loggerhead, Kemp's ridley, green turtle, and hawksbill turtle.

2. Three other species of sea turtles include the olive ridley native to India, the flatback turtle native to Australia, and black turtles who are confined to the Eastern Pacific.


B. Reason for my interest in the topic:

1. I watched a documentary which followed a female turtle through a brief period of time in her life:

a. Early into the show she gained the sympathy of the viewers as she was denied a mating partner with the surrounding males choosing other females.

b. When she finally "hooked" a mate she nearly drowned by the shear weight of the male on her back.

c. Later, she was caught in bouancy devices of Costa Rican shrimpers such as empty milk jugs and bleach bottles attached by a rope.

d. The turtle's shining moment on screen was finally completed when she swam directly into a fisherman's net only to be considered bycatch by the men who encountered her. When she was brought to the surface with the rest of the catch, she was stripped of her eggs and released into the water to ultimately perish with the traumatizing last words of the narrator, "our turtle will never return to the shores of her birth."


II. Shrimping

A. Detriments

1. Before implementation of protective measures in the late 1970's, direct mortality of an estimated 5,000 to 50,000 loggerheads and 500 to 5,000 Kemp's ridleys was was believed to occur yearly as a result of drowning in shrimp trawls.

2. Turtles are in danger with shrimping because, if forcibly submerged in any type of restrictive fishing gear, they will eventually suffer fatal consequences from prolonged lack of oxygen or seawater taken into the lungs.

3. The proportion of dead or comatose turtles are 0% for the first 50 minutes of capture and rises to 70% after 90 minutes.

B. Development of TED and Implementation of protective legislation.

1. 1978 - The U.S. National Marine Fisheries Service and the Sea Grant Program began to develop trawl modifications in the form of TEDs or Turtle Excluder Devices that allow captured sea turtles to escape the trawl through an escape hatch.

2. 1987 - Regulations required seasonal TED use in offshore shrimp trawlers from North Carolina to Texas. These regulations were not finalized and fuly enforced until September of 1989.

3. 1994 - Legislation was passed requiring year-round use of certified TEDS by U.S. shrimpers from North Carolina to Texas.

4. TED use in South Carolina is believed to have reduced loggerhead capture and subsequent drowning by 44% annually. However, repeated capture may cause mortality despite TED utilization.


C. Need for international use of TEDs

1. Because sea turtles are highly migratory, effective protection must be enforced by all shrimping nations.

2. In 1993, Mexico began to enforce the use of TEDs in the Atlantic and Carribean zones.

3. The U.S. National Marine Fisheries Service is currently providing bycatch and TED advisory service to Pacific Rim and Indian Ocean fishing nations.


III. Fishing

A. Detriments

1. Sea turtles are also vulnerable to capture in longline, paired trawls, and gill net fisheries as well as lobster and crab pots and hook and line fishing.

2. However, mortalities are only 10% of those from shrimp trawling.

3. Unattended nets other than shrimping nets are the second largest source of mortality to sea turtles.


B. Two prevalent fishing methods.

1. Longline - Consist of miles of fishing line with baited hooks at approximately four foot intervals. These may cause entanglements and mutilation. They are especially dangerous to soft shelled turtles who become impaled on the hooks. Longlines usually use chemical lightsticks to lure target species to the bait and end up attracting turtles.

a. Leatherbacks are usually found entangled in longline sections.

b. Loggerheads, greens, and Kemp's ridleys are more likely to suffer direct damage from the hooks.

2. Gill nets - Large nets, up to 2 kilometers long and 30 meters deep, made of monofilament fiber that is nearly invisible when in the water. Whilefish, in their attempt to swim through the net, become caught at the gills and drown, turtles are simply caught and drown or suffer severe physical damage.


D. In India, four new fishing quays have generated up to 2,00 annual deaths of olive ridleys yearly as a result of aphyxiation or being clubbed to death by fisherman. The government has banned fishing 5 kilometers to 20 kilometers off the shoreline. Wildlife groups are currently campaigning for the area to be made into a UN Biosphere Reserve and World Heritage Site.

CONCLUSION:
- We must continue to utilize TEDS and create new protective innovations.
- We must utilize legislation effectively.


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