Mark Van Arsdale: Marine Debris, September 22, 2018

NOAA Teacher at Sea

Mark Van Arsdale

Aboard R/V Tiglax

September 11 – 26, 2018

 

Mission: Long Term Ecological Monitoring

Geographic Area of Cruise: North Gulf of Alaska

Date: September 22, 2018

Weather Data from the Bridge

Southeast wind to 20 knots, rain showers, 6-8 with occasional 12 feet seas

59.913 N, 144.321 W (Kayak Island)

 

Science Log

Marine Debris

The wind came up a bit today, and so did the waves, but we are far enough ahead of schedule that the captain and head scientist decided we should take a two-hour excursion to Kayak Island before taking the eighteen-hour trip into Prince William Sound.  The Tiglax has a pretty deep draft, and the waters surround Kayak Island are shallow, so the boat was anchored about a mile off shore.  The waves were pretty mellow when we departed and it was a pleasant zodiac ride to shore.

The ocean side of Kayak Island is as remote as you can get, but it is covered with human trash. Marine debris is not new, fishing lines, nets, and glass floats have been washing up on beaches for hundreds of years, but the issue changed with the advent of plastics in the 1950’s.  Plastic is buoyant, supremely durable, and absolutely ubiquitous in modern human society.

The beach we walked on faces the ocean and the intense energy of winter storms was obvious.  There were logs thrown up to the high tide of the beach that were nearly four feet in diameter.  The rocks on the beach were polished, rubbed free of their edges.  Driftwood pieces were sanded smooth by the energetic action of waves smashing against rocks.  There were all kinds of interesting things to discover, including fresh bear tracks and some rather large piles of scat.  But more than anything else, there was plastic.  Plastic bottles, plastic fishing floats, fishing line, and wide variety of other refuse.  Some of it below the high tide line, and much of it thrown far back into the dense alder and salmon berry bushes above the high tide line.  Labels and lettering indicated much of the debris was from Asia.  Some of it may have been debris from the large tsunami that hit Japan on March 11, 2011, but much of it was just fishing gear lost during ordinary storms or accidents.

The Kuroshio Current

The Kuroshio Current

So how does fishing gear from Taiwan or Japan end up on a remote Alaskan beach?  Currents is the simple answer, specifically, the Kuroshio Current that flows towards the northeast from Japan.  The Kuroshio Current is a swift moving, warm water current, and it pushes debris into the North Pacific Gyre.  A Gyre is clockwise moving merry-go-round of ocean moved by the rotation of the Earth around its axis and by the prevailing winds.  Much of the debris from Asia gets trapped in that Gyre and coalesces into a floating soup of trash known as the Great Pacific Garbage patch. Some of that debris ends up washing ashore on the islands of Northwestern Hawaiian Archipelago, and some of it takes a left-hand turn, getting caught up in the counterclockwise movements of the Gulf of Alaska Current.  Kayak Island sticks out into the Gulf of Alaska like a hitchhiker’s thumb, and does a good job of catching floating debris.

Kayak Island Alaska

Kayak Island Alaska

Marine debris is more than a problem of unsightly litter.  Fishing gear lost in the water keeps on fishing, catching fish, birds, and sea turtles.  Plastic breaks apart into smaller pieces and ends up in the bellies of seabirds, turtles, marine mammals, and fish.  It’s not uncommon to find dead sea birds in the Northwest Hawaiian Islands with bellies completely filled with human trash.  Seabirds don’t consciously eat plastic, but in lower light conditions floating plastic can look like squid or krill.  To a hungry sea turtle, plastic bags and bottles can look like floating jellies and may clog the digestive system of an animal that eats them.  Plastics also concentrate potentially toxic organic chemicals that can work their way up the food chain into the fish and seafood that we eat.

Much to the annoyance of the crew, we picked up some of the larger floats and brought them on board the Tiglax. Larger efforts have been organized to do summer clean-up work on the outer islands of the Prince William Sound, but their efforts are a drop in a very large bucket.  The problem of plastic debris is enormous and in desperate need of a global solution.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Marine debris, Kayak Island.

Personal Log

Big Wave Riders

A rainbow visible as we left Kayak Island.

A rainbow visible as we left Kayak Island.

It doesn’t take long for waves to build in the Gulf of Alaska.  Within an hour and a half, the waves had risen to six feet with occasional ten foot monsters cresting just off the beach.  You could see white caps and even a mile away on the beach you could see the Tiglax bobbing up and down.  Marin, our ever-calm skiff driver, told us in a pleasant voice that the ride would be a little bumpy and that we might be “uncomfortable.”  In reality, it was a harrowing fifteen minutes that seemed to take much longer. I was sitting in front of the zodiac and was thrown several feet in the air more than once as we crested waves much larger than our boat. While on the beach I had discovered an intact 500-watt red lightbulb, used as a squid attractor by fishermen in Asia.  We had seen some of these floating on the surface the last few days, and to me it was the perfect piece of marine debris to take back to my classroom.  Unfortunately, that meant I was riding the bucking bronco that was our zodiac with a very fragile piece of glass in my left hand.  As I was getting air going over each wave, I was very conscious of the potential laceration I was risking to my hand or worse to the rubber zodiac.  Somehow we made it back to the boat, light bulb intact.  For the last two weeks, the Tiglax has grown to feel quite small, even confining, but as we approached the boat it seemed gigantic, dwarfing our skiff with its large steel hull crashing up and down in the waves like a giant hammer.  We tossed our bow line to the crew waiting on the back deck and they held us marginally in place as each of us timed our climb up a safety line with a rising wave.  “Don’t jump, take it slow, wait for the next wave if you need to,” said the captain.  The three other passengers on the zodiac did just as instructed.  The last passenger out, I grabbed the safety line with my right hand, but was unable to climb because of the glass treasure in my left hand. I jumped, skidding onto the back deck as if it was home plate, light bulb still in my left hand.

[Postscript: That lightbulb survived a trip across the Pacific Ocean, washing ashore on a rocky beach, and a trip to the Tiglax by a possibly foolish collector.  However, it only survived 24 hours in my classroom, smashed by an unknown student while I was visiting the bathroom.  Just so you know, high school students are rougher than the Pacific Ocean.]

Red Light Bulb Marine Debris

Red Light Bulb Marine Debris

We all managed to get back on board safely.  The experience and training of the crew really showed through.  When asked later if that was crazy, they answered with a casual dismissal, “just another day at the office.”

We got underway in large seas, six to eight feet, with the occasional twelve-footer.  I don’t know the techniques used to calculate such things, but some of those waves were huge.  As we positioned the boat perpendicular to the waves, each dip into a trough sent spray crashing over the bow of the boat.  I went up to the flying bridge, held on tight to a railing, and enjoyed the ride. The waves were wild and beautiful.  The sun occasionally peaked out from the clouds and the seas reflected a diverse assortment of blue and grey hues.

At the end of Kayak Island there stands the sharp cliffs of Point Elias, a lighthouse at its base, and a rock spire called Pinnacle Rock in front of it.  I’ve seen pictures of this place. It’s an iconic Alaskan image.   I felt lucky to be watching it as we rounded the point and headed into Prince William Sound for the last leg of our trip.

Did you know?

The size of a wave is determined by the multiplication of three variables.  The speed of the wind, the duration the wind blows, and the fetch (distance the wind blows.)  Increase any of those three and waves get bigger.  The size of waves can also be impacted by changing tides or currents and the specific topography of a shoreline.

Animals seen today

  • Stellar Sea Lions
  • Sea otter
  • Lots of birds including Haroquin ducks, double crested cormorants, gulls, common murres, and a blue heron

Nikki Durkan: Global Commons, June 13, 2015

NOAA Teacher at Sea
Nikki Durkan
Aboard NOAA Ship Oscar Dyson
June 11 – 30, 2015

Mission: Midwater Assessment Conservation Survey
Geographical area of cruise: Gulf of Alaska
Date: Saturday, June 13, 2015

Weather Data from the Bridge:
Wind speed (knots):  14.16
Sea Temp (deg C):  8.97
Air Temp (deg C):  8.06

Science and Technology Log

During my first several days in Kodiak, I spent as much time as possible exploring the island on foot.  I hiked up Pillar Mountain to the wind turbines which now help to make Kodiak virtually 100% renewably powered; 14% comes from these turbines while the bulk of the electricity is generated by Terror Lake hydro-power facility located within the interior of the island.  The hydro and wind generation replaced a diesel powered generator and resulted in many benefits to the town and our atmospheric global commons.

View from Pillar Mountain

View of turbines from Pillar Mountain

The idea of a global commons is one I spend a lot of time discussing in the first days of my environmental science course.  The Global Commons includes resources or regions outside the political reach of any one nation state:  the Atmosphere, Outer Space, Antarctica, and you guessed it…the High Seas!

June is National Ocean Month – and the theme for this week is marine debris.  I recently learned a new doctrine of mare liberum (free sea for everyone), but I’d like to add the latin word for responsibility, officium.  Dumping wastes is commonplace with the mantra of “dilution is the solution to pollution” and this practice continues to create challenges in our oceans.  Plastics pose a major threat to our marine life and NOAA is taking significant steps toward reducing plastic pollution through a variety of educational campaigns.  Plastic marine debris can come from a variety of industrial and domestic products, as well as lost or discarded fishing equipment.

While exploring the lovely little town of Kodiak, I came upon the rare plastic Iqaluk (Iñupiaq word meaning fish):

Sculpture constructed from collected marine debris

Sculpture constructed from collected marine debris

Another challenge facing our Global Commons includes over fishing in the High Seas.  Have you eaten Fish sticks, Filet-o-fish, Imitation-crab….otherwise known as Alaskan Pollock?  My mother often told me she craved McDonald’s fish sandwiches while pregnant with me; perhaps those sandwiches somehow led me to this spot 20 miles off the Aleutian Islands?  One of the main reasons we are on the Oscar Dyson for the next three weeks is to gather data on the Alaskan Pollock populations so that the fishery can be maintained at a sustainable level.  This Alaskan Pollock commercial fishery is one of the most economically valuable and well managed fisheries in the world.  Part of this success is due to the implementation of the MSA (Magnuson-Stevens Fishery Conservation and Management Act) that set up a system governing the EEZ (Exclusive Economic Zone – waters three to 200 miles offshore), and also established NMFS (National Marine Fisheries Service) under NOAA (you better know what this means).  The UNCLOS (UN Convention on the Law of the Sea) provides international guidelines and law for our oceans.  Acronyms…scientists and the military love them.  I will learn to love them.

 Personal Log

On the topic of marine debris, there are often jokes made on the bridge about the too-fat-to-fly puffins. They furiously flap their little wings in front of our ship.

Tufted Puffin

Tufted Puffin Photo credit: NOAA image gallery

Apparently cribbage is the game to play on the Oscar Dyson and thanks to Emily Collins (fisheries biologist), I now have another card game to add to my repertoire.  Ever tried to ride a stationary bike on a ship?  The feeling is hard to describe and I must have a sensitive stomach because occasionally I feel as if I am on a roller coaster! Currently I am sitting in my stateroom listening to the sloshing ocean that gurgles and surges with the swell against the wall; the sounds are 95% soothing and 5% terrifying.  I will not get sea sick and I will do my best not to become marine debris….
Did You Know?  In the event that I have to abandon ship, my “Gumby suit” will help me survive the frigid waters of the Gulf of Alaska.
Donning my Immersion Suit!

Donning my Immersion “Gumby” Suit!

 

Taylor Parker, April 27, 2009

NOAA Teacher at Sea
Taylor Parker
Onboard NOAA Ship Oscar Elton Sette
April 19-29, 2009 

Mission: Hawaii Bottom fish Survey
Geographical Area: South side of Oahu
Date: April 27, 2009

Weather Data 
Partially cloudy.
Minimal Winds.
Air temp: 75F.

Scientists deploying the CTD

Scientists deploying the CTD

Science and Technology Log 

Similar to the smaller CTD that we dropped from the SAFE boats, there is a much larger one on the Sette that is dropped almost nightly. The large CTD is different in several ways: it drops to a depth of 6800 meters while the smaller one will only go 600 and the larger CTD can measure many more components. It determines conductivity, temperature, salinity, dissolved oxygen, and flourescence. Conductivity is the amount of electrical current allowed within the sample, salinity is then measured by the conductivity and temperature, dissolved oxygen is the amount of oxygen found within between the water molecules and fluorescence is, well, exciting. Flourescence is the measurement of chlorophyll at different depths; to do this a little LED light is shone into the water to see the excitability of the algae. Determining the amount of chlorophyll, and subsequently the amount of algae, helps to, among other things, measure the amount of the oceans ability to absorb greenhouse gases.

Prior to the departure of the cruise, the scientists set up sampling sites along transects on a grid system near shore off the Kona coast. They are compiling data over the years to analyze changes in the physical characteristics of the ocean. This part of the research aboard the Sette is really interesting and the impacts of the data are obvious. However, there wasn’t much for me to do with this other than take photos of the Science Techs do their job and ask them questions. That is quite alright though; I lost a couple hooks while bottom-fishing but I don’t think that I want to be responsible for losing that big piece of equipment.

A Sample of the Marine Debris Encountered

A Sample of the Marine Debris Encountered

Earlier in the day, I was participating in the routine I/K trawl and we came across a slick that had perfect conditions for the billfish we were looking for. We dropped the net and slowly came upon the slick. We set everything in the water and even put the safety line across up. Within ten minutes the entire trawl was filled with marine debris, it was filled with trash. Debris accumulation is apparently normal for slicks; along with being an area where small fish can be found, the same ocean currents bring planktonic debris. And, according to the scientists who study billfish, it is good habitat for fish larvae. Not this time. This time the whole net was filled with trash and very little of anything else. We started going through it and found a crab and a shrimp and pounds of plastic. We collected everything and dropped the net in again hoping to keep it down there longer. While the remaining trawls were less trashy, there were still significant amounts of litter strewn about.

Personal Log 

The large CTD required trained professionals so I sat back and watched the two techs maneuver the large instrument. I spoke with them after to understand what they were doing. What I found most interesting was the use of the fluorometer to help measure the ocean’s ability to absorb greenhouse gases. Considering the challenges facing our planet and oceans, this is incredible data that they are collecting and when the results are analyzed, I can’t wait to see what they read.

Sargassum fish

Sargassum fish

Another challenge is one that we faced when trying to run I/K trawls. The amount of litter in the oceans is staggering. I have worked on many beach cleanups and have run tons of classes, educating hundreds of kids about the importance of watershed responsibility. Seeing the garbage floating freely in the water, clogging the runways of slow currents in the oceans is depressing. Talking with the other scientists they suggested I take a look at NOAA’s Marine Debris Program. This is a very useful and informative website describing the many factors of trash in the ocean: awareness and information about hazards, education, removal projects, etc. This is a very pressing problem considering debris, and specifically small plastics that look like food, is found everywhere where the ocean touches shore.

Animals Seen Today 
Like I said, we were picking up mostly trash in our trawls and the CTD doesn’t pick up many animals. One of the small boats did happen to pick up a kind of Frogfish called a Sargassum fish (Histrio histrio). I was reading about them and apparently they have one of the smallest brains in proportion to their body and they are highly cannibalistic. 

Jacob Tanenbaum, October 12, 2008

NOAA Teacher at Sea
Jacob Tanenbaum
Onboard NOAA Ship Henry Bigelow
October 5 – 16, 2008

Mission: Survey
Geographic Region: Northeast U.S.
Date: October 12, 2008

Science Log

Here is a sample of what has come up in the nets overnight.

Sea stars and baby invertebrates

Sea stars and baby invertebrates

Here are several different types of sea-stars. I am always amazed by the wide variety of these creatures that exist in the ocean.

a brachiopod

a brachiopod

This little fellow might not look like much, but it has an interesting history. This creature is called a brachiopod. It belongs to one of the oldest family of creatures on earth. There have been brachiopods in the sea for at least 550 million years. That is long before there were even plants on land, let alone animals and dinosaurs. It is a simple shelled animal that has a single stalk that helps is stay attached to the rocks around it. Click here to learn more about this amazing creature.

a brachiopod

a sea cucumber

Here is a sea cucumber. They live at the bottom of the sea and can be found all over the world. They are used to make medicine in some countries in Asia.

Sargassum up close

Sargassum up close

Remember that large raft of sargassum weed we saw yesterday? Some came up in the nets today. Here is what it looks like close up. She the little pockets that hold air? They help the sargassum stay afloat.

This is a sea spider.

This is a sea spider.

And of course, there is always garbage. We keep getting bits and pieces each time the nets come up. Here is a sampling. We found one entire Butterfinger candy bar with the chocolate still inside (no, we did not eat it), as well as some rope. How do you think it got here?

Let take a closer look at a sensor called a CTD. That stands for conductivity, temperature and depth. Remember the drifter buoy that we released a few days ago? It measures temperature on the top of the water and it can drift all over the ocean taking readings. A CTD takes its measurements as it descends through the water column and can go all the way to the bottom.

Trash pulled up with the rest of it

Trash pulled up with the rest of it

Have you ever seen barnicles move? They do. We found these huge barnicles in our net and we put them in water to encourage them to come out. Check out this video!

A lot of people have asked me about sea-sickness. Sea Sickness happens when your brain and body, which are constantly working to keep you balanced, get confused by the rocking of the ship. It is a terrible feeling, and I’m glad I have not been sea-sick at all on this trip. Some people do better than others on boats. I do not tend to get sea-sick unless the waves are very high, and I am used to the rocking of the ship now. The other night I was working on deck and I caught sight of the moon moving quickly across the sky. I wondered why it was moving so fast until I realized it was my ship that was moving in the sea and me with it. The moon only seemed to move. I guess that means I’m used to the rocking back and forth and hardly notice it now.

——————–

More marine debris

More marine debris

MLL, SPL and MCL, Snuggy and Zee are having a great time and none of us are sea-sick. I put more information about it in the upper part of the blog entry. Thanks for writing.

SQ, CS, KM and VM: It is nice fall weather. Not too hot, not too cold. I love it. I have not felt uncomfortable even when I am working out on the wet deck of the ship.

GG: It is not hard to sleep at all most nights. There was only one night where the waves were high and I bounced around too much to sleep well. The rest of the nights were fine. The ship rocks me to bed at night. I do miss WOS. See you soon.

Dena Deck, July 20, 2006

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

Mission: Ecosystem Survey
Geographical Area: Central Pacific Ocean, Hawaii
Date: July 20, 2006

Science and Technology Log

Because of their remoteness, the largely uninhabited, and dynamic ecosystems of the Northwestern Hawaiian Islands are often thought of as pristine environments. A more accurate term is “near-pristine,” because this isolated archipelago acts as a giant filtering comb in the middle of the Pacific Ocean, picking up debris that float from afar. Signs of trouble are not immediately apparent to the casual observer, but a closer look reveals ghost nests (discarded or lost fishing nets) caught on the reefs, debris of all sorts on the beaches, and plastics inside the skeleton of albatrosses. Even here, pollution has left its mark. But it is not an indelible mark, and there are devoted groups working hard to erase it from the map of the Northwestern Hawaiian Islands.

The majority of the debris that accumulates on these islands is fishing gear, and lots of it. In addition to destroying the coral upon which it settles, derelict fishing gear can also cause entanglement for the highly endangered Hawaiian monk seal, the threatened green sea turtle, fish, invertebrates, and seabirds.

The Northwestern Hawaiian Islands are in the path of the North Pacific Subtropical Convergence Zone, which stretches from Japan to the West Coast of the US. This zone is a large, shifting line that is the product of ocean currents and wind interactions where areas of the surface waters meet. The convergence of different water masses result in the aggregation of trash, being carried by each water mass and deposited along this zone. The subtropical convergence zone can actually be observed from a thousand feet in the air as a semi-continuous line of trash, earning its nickname as “East Pacific Garbage Patch.”

The group charged with the removal of these pieces from these remote atolls and islands is the Marine Debris Project, part of the Coral Reef Ecosystem Division, under the NOAA Fisheries, Pacific Islands Fisheries Science Center. The group recently completed a large-scale project over the course of the last five years (which just ended in 2006) to remove as much of the derelict fishing gear in the Northwestern Hawaiian Islands as possible. Going out on missions stretching up to four months at a time, two liveaboard mother vessels would carry eight divers each. As the seasons change, the subtropical convergence zone can be observed performing an annual dance in the North Pacific Ocean ballroom. When in the winter this line shifts south and passes the Northwestern Hawaiian Islands around January and February, the large, fractured atolls become a giant comb, trapping these floating debris from all around the North Pacific rim. During the summer, this convergence zone shifts north again.

After reaching a predetermined location, the Marine Debris Project has two methods for covering an area. In shallow reef areas, they snorkel, with the boat nearby. In deeper areas, they do “towboarding,” which involves a small board attached to the boat, which is running on average of between 1-2 knots. Inhaling deeply, and with a quick maneuver of the board, the free diver pairs can then go to the bottom, covering it in a serpentine fashion. Each diver covers a transect of 7.5 meters apiece, checking both sides of this transect while staying within visual range of the divers on either side. The distance among divers varies according to the visibility, but it’s never more than 15 cumulative meters, or approximately 45 feet, between the combined diver pair.

One of the initial efforts undertaken in 1999 at Lisianski Island and Pearl & Hermes Atoll recovered 14 tons of derelict fishing gear. Most of this gear came from trawl netting, followed by mono-filament gillnet, and maritime line. This effort also showed this gear to affect the coral reef ecosystem of the Hawaiian Archipelago (Donnohue et al., 2001). To ensure that the whole swath is observed, divers take a daily visibility measurement by placing a small piece of net underwater, and determining from how far away this net can be seen. Surveys are then conducted, with a slight overlap among each swath to ensure full coverage. When derelict debris is found, they release the board, go to the surface, and raise their hand. At this point, the towing boat turns back, obtain latitude and longitude with a GPS unit, and help the diver retrieve the fishing gear.

The Marine Debris Project, having completed their focused clean up activities on the Northwestern Hawaiian Islands, has now entered into a maintenance phase. This will help them estimate the accumulation rates at repeated zones, which will allow them to determine the frequency of future clean up efforts, and the amount of funds needed. All of this to ensure that trash does not become constant stain in an otherwise vibrant and healthy environment. Since 2002, about 200,000 lbs of net have been recovered this way each year. Many of these pieces can be retrieved by one or two divers, but occasionally a particularly large net is found. One particular net had a weight in excess of 5,000 lbs, and took all divers working together to cut it into sections and pull it out of the water. Over the years, the group has found sharks, sea turtles and monk seals trapped in these nets. One even had a portion of a whale’s spine, apparently having caught the animal in the high seas.

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.

Patricia Greene, July 17, 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 17, 2006

Spinner dolphins in the lagoon around Green Island at Kure Atoll, State Wildlife Refuge.

Spinner dolphins in the lagoon around Green Island at Kure Atoll

Science and Technology Log

The first creatures we experienced at Kure Atoll were the spinner dolphins. These creatures delight in playing in the wake of our bow; doing somersaults, spins, and jumps; crisscrossing fearlessly in front of our boat, then losing interest when we slow down. Scientists are not sure what make spinner dolphins exhibit this type of behavior. Interestingly, scientists have observed that spinners in the Northwestern Hawaiian Islands have a different social structure than those around the main Hawaiian Islands. In the Northwestern Hawaiian Islands, dolphins demonstrate group cohesion and typically stay together in the same group socializing in the lagoons or when they feed offshore. In the main islands a spinner dolphin may join a different feeding group every night; scientists have dubbed this behavior “fission-fusion,” since groups form and split repeatedly.We observed mothers with calves at their side; the babies easily keeping up and enjoying the sport as much as the adults. During the day the dolphins are relatively inactive and take group naps but at night they leave the atoll to forage and feed.

Cynthia Vanderlip and her team conduct spinner dolphin surveys in the lagoon around Green Island at Kure Atoll.

Cynthia Vanderlip and her team conduct spinner dolphin surveys in the lagoon around Green Island at Kure Atoll.

We observed a large group of spinner dolphins at Kure; approximately 70, although they swam so rapidly they were difficult to count. Other pods or groups have been identified at Pearl and Hermes and Midway. Typically, crossover between these groups in the Northwestern Hawaiian Islands is rare. Recently we visited Southeast Island at Pearl and Hermes and interviewed NOAA Fisheries monk seal researchers; Hugh Finn, Jessie Lopez, and Kennedy Renland regarding their spinner dolphin research. Basically, the dolphin research is done at the same time as they do the atoll counts for the monk seals; approximately every third day if the weather cooperates. If winds exceed 15 knots, safety becomes a concern and researchers will not go out in the small boats. During an atoll count day the researchers leave camp at 9:00 am and return at approximately 4:00 pm. For safety reasons, only two researchers go out in the boat at a time; one person remains on shore and monitors the radio in case assistance is needed. During an atoll count they will visit North Island, Seal Kittery, Grass Island, and various sand spits to assess the population.

Majestic Hawaiian spinner dolphins in the clear lagoon waters of Kure Atoll, State Wildlife Refuge.

Majestic Hawaiian spinner dolphins in the clear lagoon waters of Kure Atoll, State Wildlife Refuge.

Dolphins at Pearl and Hermes Atoll usually travel in groups or pods of 50 to 60. Mothers with calves are often seen at this time of year. Researchers explained that the age of the calf can often be estimated by the existence of “fetal folds.” The female dolphin has a 12-month gestation period and while inside the mother the calf develops creases in its body.  These “fetal folds” will exist until the calf is two or three months of age.Dolphin surveys involve taking digital photographs of as many dolphins as possible. This year the Pearl and Hermes Atoll researchers have taken approximately 2,000 photographs to date. These digital images will be forwarded to Dr. Lezek Karczmarski at Texas A&M and fed into a database for his research. Individual dolphins usually have distinctive cuts, scars or marks that help identify them. Researchers also take small biopsy samples from the dolphins. This is accomplished by using a crossbow type instrument with a dart that removes a tiny piece tissue from the skin.

During a dolphin survey, researchers record the start and end times, initial and final GPS coordinates, swell, water depth, water temperature and bottom type. They assess the numbers and ages of any calves observed and record the numbers of juveniles and adults.  Total number of digital images taken and any ID ratio is also recorded. The Northwestern Hawaiian Islands spinner dolphin pods have a habitat relatively free from typical human interference. Threats to dolphins in more populated areas include collisions with vessels, entanglement in fishing nets and other marine debris, and acoustic disturbances. In the Northwestern Hawaiian Islands few of these threats exist. Spinner dolphins are protected under the Marine Mammal Protection Act. Exact population numbers worldwide are unknown.Spinner dolphins have a wide range; found in tropical waters, subtropical, the Pacific, Atlantic and Indian Oceans. They feed on mesopelagic fish, squid, and shrimp. The females reach sexual maturity at 7 to 10 years, and give birth to a single calf every other year. Calves are weaned at seven months. Spinner dolphins may have a life span exceeding 20 years.

Special thanks to the Hawaiian Islands National Wildlife Refuge, United States 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.