NOAA Teacher at Sea Donna Knutson NOAA Ship Oscar Elton Sette September 1 – September 29, 2010
Mission: Hawaiian Islands Cetacean and Ecosystem Assessment Survey Geograpical Area: Hawaii Date: September 9, 2010
Green Sea Turtle Rescue
Mission and Geographical Area:
The Oscar Elton Sette is on a mission called HICEAS, which stands for Hawaiian Islands Cetacean and Ecosystem Assessment Survey. This cruise will try to locate all marine mammals in the Exclusive Economic Zone called the “EEZ” of Hawaiian waters. The expedition will cover the waters out to 200 nautical miles of the Hawaiian Islands.
Also part of the mission is to collect data such as conductivity for measuring salinity, temperature, depth, chlorophyll abundance. Aquatic bird sittings will also be documented.
Science and Technology:
Latitude: 24○ 45.4′ N
Longitude: 163○ 04.2′ W
Clouds: 6/8 Ci, Cu,
Visibility: 10 N.M.
Wind: 12 Knots
Wave height: 2-3 ft.
Water Temperature: 26.2○ C
Air Temperature: 25.8○ C
Sea Level Pressure: 1022.0 mb
Green Sea Turtles are very ancient animals. These reptiles were around when the dinosaurs still walked the Earth. Their top and bottom shell is actually much harder than other turtles. Another difference between the Green Sea Turtle and its “cousins” is that the Green Sea Turtle cannot pull its head into its shell.
Even though the streamlined shell is extremely tough, it is very lightweight. They do not have feet, but rather flippers which allow them to be graceful swimmers without much effort. They usually swim one mile per hour but can reach thirty-five miles per hour when need be.
Sea animals all need a system to dispose of the increased salt content in their bodies, and the Green Sea Turtle is no exception. It has a salt gland behind each eye. The turtle will shed extra salty tears when it needs to remove the excess salt. So when the turtles seem to “cry” they are only keeping their bodies chemistry in check.
Four of the seven species of sea turtles live in the water surrounding Hawaii. The four types are the Green Sea Turtle, the Hawksbill, the Leatherback and the Olive Ridley. The most common is the Green Sea Turtle.
Adult Green Sea Turtles are herbivores and eat mainly sea grass. The young turtles are carnivorous and eat mainly jellyfish and other invertebrates. The adults can weigh up to five hundred pounds and are usually found around coral reefs. The young turtles wander the sea until they are old enough to mate.
In the wild Green Sea Turtles grow slowly and can take ten to fifty years to reach their sexual maturity. This is one reason the popuation, once depleted, can take many years to recover. Their life span is unknown.
Adult females and males look similar with one exception. The male’s tail is much longer and thicker than the female’s short stubby tail. All the juveniles look the same, so determining sex by outside appearance is not possible.
Females return to nest on the same beach they left as a small turtle out of their eggl. It is unknown how they find their way back much like other animals that seem to have similar senses.
Hawaii’s Green Sea Turtle migrates as far as eight hundred miles from their feeding sites along the coast. The males and females migrate together, mate and return. The females do not mate every year. Ninety percent of the Hawaiian Green Sea Turtles lay their eggs on French Frigate Shoals which is area North of Kauai and in the southern part of the Northwestern Hawaiian Islands. It is estimated that only one percent of hatchling turtles survive to mating age.
Green Sea Turtles have only two predators, man and sharks. People hunt the turtles for their meat, particularly for soup, their shells for souvenirs, and also for their eggs. Depending on their location, Green Sea Turtles are either threatened or endangered. They are threatened in Hawaii and endangered in Florida.
Thousands of Green Sea Turtles die every year by other sources as well. Thousands die in nets and other discarded gear. Plastics are harmful to turtles because once ingested they may clog their digestive systems. Green Sea Turtles have also been suffering from a disease discovered in 1980 that causes tumors. These tumors although harmless may block the throat and cause starvation or grow inside around internal organs.
Little is known what causes the tumors. It is speculated that they might be associated with changes in the ocean environment by pollution, or change in water temperature or increased ultraviolet rays.
While on the flying deck Eddie Balistreri, an observer, noticed something floating about 300 m from the ship. Abbie Sloan, mammal observer, and Scott Mills, bird observer, spotted a turtle in the floating debris. Juan Carlos Salinas, mammal observer, called to the bridge and asked the helmsman to turn the ship inorder to check out the turtle. While the ship was turning the scientists lost track of the tangled turtle.
I felt the ship turning and heard mention of a turtle on the ship’s radio and quickly got to the deck. Just as I looked down there it was, they had found it, a turtle struggling to keep its head up in the floating mass. You could tell it was alive because it was moving its neck back and forth and bubbles where seen when the turtle submerged.
By this time all sixteen people of the science crew were watching the trapped turtle. They were concerned with its fate because so many of these animals die in nets. It was decided that this was a worthwhile rescue mission and a small boat was launched. Abbie and Ernesto Vazquez, mammal observer, were assigned for this mission. Ray and Mills, both deck hands that have been on every small boat launch, were ready to help the turtle also. The scientists tell me it is very rare to do such a thing on these mammal cruises, and no one had done anything like it on previous cruises. In other words, I was receiving a great bonus! Everyone was eager to help out an animal in need.
The small boat did not have to go far before it came to the turtle. It was trying desperately to break free of the fishing net. There were crabs and barnacles also clinging to the net. It is possible the turtle thought it could get an easy meal and accidently got trapped. The turtle seemed healthy judging by the amount it was struggling when the small boat crew pulled the net into the boat.
Ray and Abbie cut the turtle lose and identified it as a Green Sea Turtle. Ray gently lowered the turtle back into the water. The size wasn’t measured but I was told it was the size of a large pizza. I asked Juan Carlos to guess how old the turtle was, and he estimated it was less than five years old.
The science crew on the flying deck knew when the task was done and the turtle was free because we saw the “high fives” in the small boat. Then it was our turn to cheer! Saving this threatened animal was very rewarding! Hopefully the little Green Sea Turtle will go on to help populate its species.