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Patricia Greene, July 19, 2006

NOAA Teacher at Sea
Patricia Greene
Onboard NOAA Ship Hi’ialakai
June 26 – July 30, 2006

Mission: Ecosystem Survey
Geographical Area: Central Pacific Ocean, Hawaii
Date: July 19, 2006

A large green sea turtle basking in the sand.
A large green sea turtle basking in the sand.

Science and Technology Log

Unlike the spinner dolphins, we have observed the Hawaiian green sea turtles tend to be rather shy and elusive. We managed to catch just glimpses of them from a distance.  Based on past slaughters by man it is no wonder these creatures would avoid contact with humans. Historically, from the late 1800’s until 1970’s these creatures were slaughtered and harvested. Finally, in 1978 turtles were recognized under the U.S. Endangered Species Act however, they are still harvested in many parts of the world.

Several adaptations make the green sea turtle well suited for life in the ocean. Special lachrymal glands in the eye assist in the regulation of salt in the turtle’s body, preventing it from becoming dehydrated. When sea turtles shed tears they are actually removing salt from their bodies. Sea turtles are capable of storing large amounts of oxygen in their blood and muscle tissue, and lungs are adapted for rapid exchange of oxygen. Green sea turtles can stay under water up to five hours. Modified forelimbs give the sea turtle an efficient forward power-stroke. Protective coloration in the form of counter shading and blending gives the sea turtles camouflage. The underneath of the shell is cream color so the turtle blends with the sky and water to anything looking up and has a dark top shell for any predator looking down.Our luck changed on Southeast Island at Pearl and Hermes Atoll in the Hawaiian Islands National Wildlife Refuge. While circumnavigating the island we viewed a large adult green sea turtle pulled out and basking on the beach. After lunch we viewed from a distance two more green sea turtles basking and swimming in the surf. Researchers told us that they often observe 10 to 20 turtles pulling out at sunset and sleeping on the beach at night. It is more common in the Northwestern Hawaiian Islands than the main Hawaiian Islands for green sea turtles to exhibit this basking behavior. It is thought the behavior may be an adaptation to the cooler waters (i.e., a mechanism of thermoregulation, or a predation avoidance strategy due to the high populations of tiger sharks).

Three endangered Hawaiian green sea turtles bask on Southeast Island in the Hawaiian Islands National Wildlife Refuge.
Three endangered Hawaiian green sea turtles bask on Southeast Island in the Hawaiian Islands National Wildlife Refuge.

Green Sea turtles reach sexual maturity at approximately 25 to 30 years and reach a weight in excess of 200 lbs. Green sea turtle’s breeding behaviors demonstrate great stamina. Pairs may remain coupled for 10 to 12 hours and both sexes have multiple partners throughout the mating season. Adult males can be distinguished from females by their longer tails and curved claws on their flippers.  After the hatchling breaks out of the shell it must then reach the surface. Hatchlings demonstrate “protocooperation” meaning they work together as a group for several days in a joint effort to reach the surface. The hatchlings take turns digging and resting. Once they are near the surface the heat of the day will immobilize them and they will not continue their escape until the evening temperatures have cooled the sand. In this way they avoid heat stress and predators.Green sea turtles are oviparous (lay eggs externally) in a sand pit on the beach. Nesting starts in May and continues through August. Critical components of the nest site must include: lack of predators, a moist substrate, and suitable temperatures and be located beyond the high tide mark. Typically the green sea turtle will lay 75 to 150 eggs at night, in a clutch and lay multiple clutches during the breeding season. Incubation takes 50 to 70 days depending upon ambient temperatures. Sex of the hatchlings is not determined at the time of fertilization or conception (no sex chromosomes) but dependent upon the temperature of the sand and individual position of the egg in the nest. This is called “TSD” or Temperature-Dependent Sex Determination. The pivotal temperature for the green sea turtle is 28.26 degrees Celsius (82.9 degrees Farenheit). This is the temperature at which equal number of male and female hatchlings will be produced. If the temperature falls below this number more males will be produced; above more females will be hatched.

Now the hatchlings must find their way to ocean, avoiding the ghost crabs of the night. It is thought they employ a variety of visual clues, “wave compass” and perhaps a “magnetic compass” in their effort to reach the ocean. Scientists believe the wave compass allows the hatchlings to get orientated directly against the incoming waves. The magnetic compass refers to the magnetite found within their brains that may align them with earth’s magnetic fields. Once they arrive at sea, they will dog paddle to open water; hiding in algae, drift lines or other floating debris.

A curious Hawaiian green sea turtle approaches underwater at Puako in the main Hawaiian Islands.
A curious Hawaiian green sea turtle approaches underwater at Puako in the main Hawaiian Islands.

During this pelagic stage they are carnivores and feed on plankton. They will remain at sea in this hatchling/early juvenile stage for years, sleeping with their flippers folded over their back to diminish their chance of becoming a morsel for some predator. This stage is a period of rapid growth; perhaps 8 to 10 cm the first year. The young turtles will re-appear in coastal waters where they will continue to grow, graze on algae and become life-long herbivores. The green sea turtle has specialized microorganisms in the hind gut that digest the cellulose in the plant material. It is possible that juveniles establish this flora by practicing “scatophagy” or the ingestion of adult turtle feces.

Another concern for the green sea turtle population has been the appearance of fibropapilloma tumors. Tumors on the eyes, throat, lungs, kidneys, liver and intestines have been documented. Scientists believe a Herpes-type virus may be responsible. The disease is quite common in the mainland Hawaiian Islands but relatively rare in the Northwestern Hawaiian Islands. These tumors may blind the turtle or choke them depending on the location of the tumor.  Fortunately, we did not observe any tumors while we have been in the Northwestern Hawaiian Islands.Typically sea turtles thrive on sea grasses, seaweeds and algae. Depending upon where they live their diets may vary; for example green turtles of the Pacific Ocean are more dependent upon algae and seaweeds than the sea turtles of the Atlantic Ocean that thrive on the sea grasses such as turtle grass. The diet of the green sea turtles at Kure Atoll consist of an algae called Codium edule. In the main Hawaiian Islands invasive alien species of algae in the marine ecosystems have displaced the native species of algae that the turtles have traditionally fed on. This has caused widespread damage to the coral reef habitats.

The Northwestern Hawaiian Islands are extremely important to the green sea turtles. It is one of the last places where turtles are not affected by man’s desire for beach front property; no issues of coastal development, domesticated predators, recreational activities, artificial lights, high speed boat traffic, or general coastal degradation of the habitat. Over 90% of Hawaii’s green sea turtles return to nest at the French Frigate Shoals. Turtles come from the far north end of the Northwestern Hawaiian Islands chain (Kure, Pearl and Hermes, Midway Atolls) and from outreaches of the main Hawaiian Islands to lay their eggs at French Frigate Shoals.

Special thanks to the Hawaiian Islands National Wildlife Refuge, United State Fish and Wildlife Service, Department of Interior for access to Southeast Island and an opportunity to spend a day with the NOAA Fisheries biologists to learn more about the spinner dolphin research they conduct during their field season.

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Dennis Starkey, July 18, 2006

NOAA Teacher at Sea
Dennis Starkey
Onboard NOAA Ship Miller Freeman
July 16 – August 4, 2006

Mission: Pollock Survey
Geographical Area: Bering Sea
Date: July 18, 2006

“Way Out There!” 

Science and Technology Log 

We are now 529 nautical miles out into the Bering Sea.  I thought there would be an occasional sea bird of some kind.  I was mistaken.  There are tons of sea birds to see!  The U.S. Fish and Wildlife Service is also conducting a survey of the density of bird life in the Bering Sea. Tamara, our bird Biologist, spends daily shifts on the Captain’s deck recording the birds that she sees in a 300-foot swath in front of the ship’s path.  She has been busy. She enters the species and numbers of birds on a computer program that works in conjunction with the ship’s radar. Some of the common species are, Northern Fulmars, Murres, Kittiwakes, and my favorite, Puffins.  The results give an impression of the density, or how many of each kind in a specific section, for the Bering Sea area. Tamara informed me that the last survey of this kind was in the 1980’s.  The weather looks calm and “beautiful sailing” conditions prevail.  There is a stratus cloud cover, but the sun has peeked out on occasion.  The temperature is currently 8 degrees Celsius.  The overall temperature range has been a bit warmer than this and has been comfortable to dress in a sweatshirt.

“How Do You Know There Are Fish Down There?” 

You see, we are not catching tons of fish. We do this on purpose.  In the past, fishermen would report catch amounts and that information would be analyzed and that was about all. This left speculation as to many variables that were not consistent.  Reports were not always accurate, locations were not disclosed, and weights weren’t reliable.  By having a research vessel conduct the survey, the results can have reliability and consistency measures.

To go out into the Bering Sea and drag nets all over the place does not make economic sense. A better solution is to find traditional fishery areas in the Bering Sea and survey those areas. Those areas happen to be along the continental shelf.  This is a comparatively shallow area of the ocean where currents of warmer and cooler water converge and circulate, allowing ideal conditions for life to flourish.  This is an area rich in phytoplankton (plants or algae) that are producers of food, which can feed lower end primary consumers (krill), that feed secondary and tertiary consumers and so on.  The Pollock find this area a favorable habitat for this reason.

So, you can’t catch them all, especially with one or two boats, so what do you do? Use technology! The computers, program software, and technology devices used make the survey possible. Echo sound is proving to be a fantastic way to find and quantify data.

Consider this scenario: It works sort of like this: You are in your bedroom reading when you hear a truck outside. You think, “It’s a big truck,” based on the type of sound and your experience listening to sounds. You knew it was a truck even though you never saw it. In order to confirm what you were hearing was a truck, you tell your mother to look out the window and let you know if it is a truck.  She might yell back, “It’s a fire truck at the neighbor’s house next door!” After she physically sees it, she can provide you with the details by providing color, length, and function of the truck.  The echo-scientists can’t exactly see each individual fish as we go by at 12 knots, but what they can do is be reasonably sure that different sound frequencies bounce back to the sonar equipment in a predictable fashion based on species. I’m informed that the fish’s swim bladders are the telltale sign. They do see a mass of colors and bunches on the computer monitor, but you can’t measure that information yet until confirmed.  Even jellyfish have their own particular patterns as do krill, and whales for that matter. The next step is to have a system to indeed find out for sure that the fish are there.

This is the part where mom is your eyewitness.  Fisheries scientists then return to the site by using satellite technology to where the characteristic patterns are detected.  Then a trawl net is lowered and dragged. What is caught is recorded.  My experience here in four trawls has shown 100% accuracy each time!  We take the collected specimens and put them on a 10ft x12ft x10-inch table for sorting.  We sort by species, gender, weight, and other collectable characteristics requested by the lead biologist. We now have the specifics of the truck, and the Pollock for that matter, based on circumstantial and physical evidence. Sounds a bit like CSI doesn’t it? A sample of less than four hundred fish is desired to make the data collection a success.  Often we get more.  The sorted data is entered in the computer and the information is combined with the cumulative data of the survey to demonstrate trends and density results for the Walleye Pollock.

Personal Log 

The MILLER FREEMAN doesn’t turn off the engine.  This diesel-powered ship runs all the time!  As we transect the grid course day in and day out, the boat maintains a rate of about 12 knots. The only time it slows is during trawl operations.  Trawling occurs when the chief scientist feels it would be good to get a sample of what she sees on the four sonar frequencies. The result to your ears is comparable to a commercial jet airliner from inside the coach.  I’d say the crew is totally used to it.  It actually seems to help me sleep!

I have participated in four Pollock hauls now.  They have all been successes!  It takes about two, to two and a half hours to conduct the scientific processing of a catch.  It is pretty slimy business!

Did You Know? 

British Scientists are researching the slime found on fish to develop a drug that would defend the body against diseases. The hope is to replicate the protection properties that fish provide to trout on our bodies. Could you imagine your roll on slime dispenser? I’m sure that’s not what they have in mind!

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David Riddle, July 17, 2006

NOAA Teacher at Sea
David Riddle
Onboard NOAA Ship Albatross IV
July 13 – 28, 2006

Mission: Sea scallop survey
Geographical Area: New England
Date: July 17, 2006

A seahorse that came up with the dredge
A seahorse that came up with the dredge

Science and Technology Log

It’s almost halfway through my watch now, and I have a little down time.  The day started with several stations that were close together, which kept us busy. Now the sampling stations are farther apart, and I’ve had time to work on some photographs of shells.

Our catches turn up lots of interesting creatures.  Some I recognize from my college invertebrate zoology course (oh, so many years ago!)  Others I’ve only seen pictures of.  There are occasional sea squirts, bulbous little creatures that squirt a stream of water when squeezed.  We find an occasional “sea mouse”, a polychaete worm, bristly-looking on the backside and shaped sort of like, well, a mouse.  Underneath you can see the segments.  Hermit crabs are abundant; many of them simply abandon their shells when they’re dumped onto the deck. This is probably not a good survival strategy, since they get dumped back overboard only to drift slowly to the bottom without any protection at all. Oh well, most everything in the ocean is somebody else’s lunch anyway. We find other species of crabs as well.  The larger ones are set aside and are sitting in a bucket which has seawater continually being pumped through it to keep them alive. I wonder whose lunch they’ll turn out to be?  We’ve caught a few small dogfish sharks, under two feet in length.  I’m told on some of the ground fish surveys they catch tons of them (literally). Considerably smaller were two needlefish, about 6 inches long and ••• inch wide.

I find myself wondering things like, “What must it be like to be that small, living in this huge ocean?”  Them I’m reminded of our little planet’s location in our galaxy, and the Milky Way’s tiny place in a universe with millions of other galaxies.  OK. Humility is a good thing.

Then too, I’m reminded that small is not always equivalent to unimportant.  Do you like breathing?  Well, consider that roughly 3 out of every 4 breaths you take come to you courtesy of the phytoplankton in the oceans of the world.  There they are, soaking up the sunshine and the carbon dioxide and pumping out huge quantities of oxygen every single daylight hour. They’re microscopic, but their importance in the overall scheme of life on this planet is enormous. I suppose it would be helpful to remember, while we’re busy saving the whales, we should take care of the little guys too.  But then, how would “Save the Plankton” look on a T-shirt or bumper sticker?

On a more practical note, we’re due to reach our turn-around point in 5 more stations.  We will have reached our southernmost latitude, which will put us due east of the North Carolina-Virginia border.  Then we’ll begin making our way back up the coast, stopping at the stations in shallower waters.  I flew to Boston from my home in western NC to take part in this Teacher at Sea experience.  So this is the closest to home I’ll be for the next 12 days.

I keep thinking I’m done with my log for the day and then something else happens.  At station 99 we caught a seahorse!  The depth was 24 fathoms, and I seriously doubt it was on the bottom, but when the dredge came up, there it was on deck.

Sightings: The osprey was still here this morning, but as of late afternoon it was gone.

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Dennis Starkey, July 17, 2006

NOAA Teacher at Sea
Dennis Starkey
Onboard NOAA Ship Miller Freeman
July 16 – August 4, 2006

Mission: Pollock Survey
Geographical Area: Bering Sea
Date: July 17, 2006

Science and Technology Log 

We made a krill trawl today to check the sonar equipment.  It was a check on one of the primary food sources of the Pollock and it helps the echo-integration specialists hone their skills at identifying Pollock versus other schools of marine organisms.  The trawling device was designed to catch a small bucket of krill of which it did. The specimens were weighed and then photographed on a scanner for later base study analysis. The greatest thing about the cruise so far is the warm, helpful welcome I received on board and the willingness of everyone to spend some time with me to share conversation, and bring me up to speed on what is taking place.

Members of the fisheries biology staff begin to count out and weigh the Walleye Pollock from the sorting table.
Members of the fisheries biology staff begin to count out and weigh the Walleye Pollock from the sorting table.

Personal Log 

I had a few days to visit Dutch Harbor while the scientific staff rotated and the ship restocked. The most impressive observation for most people living in the lower forty-eight states must be the abundance of our national bird, the Bald Eagle.  They congregate here for the free fish that spill overboard at one of the many fishing plants. They are rather like pigeons here. The harsh climate does not suit trees well so the eagles perch on the hillsides and, more often, on the store rooftops and streetlights right in town.

Living on the 205ft MILLER FREEMAN takes some getting used to.  I am not accustomed to the small living quarters on board yet.  I am rooming with the two Russian scientists in a “cozy” 54 sq. ft. bunkroom. I sleep on the top bunk and have been pleasantly lulled to sleep by the drone of the engine the past two nights.  The sea has been calm but overcast.  I have had the chance to see Minke whales, Dall’s porpoises, fur seals, and incredible amounts of sea birds!  I have been getting used to the many hatches, decks, and stairways. I still find myself laughing out loud when I come to a dead end or the wrong deck just trying to get to my room.