Wednesday, October 7, 2009

Problems of the Month--October

Back Home At Last!

Loggerhead Sea Turtle General info:
Size: Typically 2.5 to 3.5 feet in carapace length (73-107 cm).

Weight: Adult weigh up to 350 pounds (159 kg).

Diet: Primarily carnivorous and feed mostly on shellfish that live on the bottom of the ocean. They eat horseshoe crabs, clams, mussels, and other invertebrates. Their powerful jaw muscles help them to easily crush the shellfish.

Habitat: Prefer to feed in coastal bays and estuaries, as well as in the shallow water along the continental shelves of the Atlantic, Pacific and Indian Oceans.

Nesting: Nest at intervals of 2, 3, or more years. They lay 4 to 7 nests per season, approximately 12 to 14 days apart. Lays average of between 100 to 126 eggs in each nest. Eggs incubate for about 60 days.

Status:U.S. - Listed as Threatened (likely to become endangered, in danger of extinction, within the foreseeable future) under the U.S. Federal Endangered Species Act.International - Listed as Endangered (facing a very high risk of extinction in the wild in the near future) by the International Union for Conservation of Nature and Natural Resources.

Threats to Survival: The greatest threat is loss of nesting habitat due to coastal development, predation of nests, and human disturbances (such as coastal lighting and housing developments) that cause disorientations during the emergence of hatchlings. Other major threats include incidental capture in longline fishing, shrimp trawling and pollution. Incidental capture in fisheries is thought to have played a significant role in the recent population declines observed for the loggerhead.
Population Estimate: 44,560 nesting females.

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On September 19, the National Aquarium in Baltimore released a Loggerhead Sea Turtle that had been in their care for over a year. The turtle was back home at last!

1. When the turtle was rescued it couldn’t swim or dive properly (both skills are needed for catching food). Part of the reason for his impairment was the 10 pounds of hitchhiking barnacles, mollusks, and sea grass that had attached themselves to the turtles shell. Once the 10 pounds of “hitchhikers” were removed they found the turtle was severely underweight! Weighing only 64 pounds with a clean shell, what percent of his weight at capture was due to the “hitchhikers”? Express your answer to the nearest tenth.

2. Once the turtle’s shell was cleaned off he was able to swim and dive properly which allowed him to catch food and enabled him to reach a healthy weight. Upon release, the turtle weighed 90 pounds, which is an ideal weight for the turtle!! By what percent did the turtle’s weight (without the hitchhikers) increase while in rehabilitation? Express your answer to the nearest thousandth.

3. To track where the turtle goes and how he is doing after his release, researchers attached a tracking device to his shell that will naturally fall off after a while. From the morning of September 19, 2009 to the morning of September 24, 2009, the turtle had swum 76.4 miles. If the turtle slept 10 hours each day, what was his average swimming speed in miles per hour during the times in which he was awake? Express your answer as a decimal to the nearest hundredth.