Tag: central pacific

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Patricia Greene, July 13, 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 13, 2006

Old fishing nets get piled up on the pier on Green Island at Kure Atoll waiting for the marine debris crew to pick up
Old fishing nets get piled up on the pier on Green Island at Kure Atoll waiting for the marine debris crew to pick up

Science and Technology Log

One reason the Northwestern Hawaiian Islands (NWHI) are so unique is that they contain some of the most isolated, pristine, and genetically pure coral reefs in the world.  Kure Atoll is approximately 1,200 miles from the main Hawaiian Islands. It represents one of the last intact, predator-dominated reef ecosystems. It is a critically important habitat to a wide range of species including seabirds, sea turtles, monk seals, and sharks.  The earliest creatures arrived on these islands by swimming, flying, or floating for thousands of miles and then with the passage of time, evolved into genetically different species. These species are referred to as ‘endemic’ meaning they are unique to that area.

Historically, man’s greatest impact on the ecosystems of NWHI has taken two major venues; importation of terrestrial alien or exotic species and mass slaughter or over-harvesting of existing endemic species.  Understanding the past can help us protect the future of the NWHI.Hawai`i has a very high incidence of marine endemism due to the age of the islands (Kure Atoll is approximately 28 million years old) and the relative isolation from other coral reefs. The prevailing currents generally run from east to west; keeping larvae from other reefs from reaching Hawai`i. Also, the waters here tend to be cooler and the wave action intense, deterring foreign species from colonizing. The marine ecosystems have been far less impacted by man than the terrestrial ecosystems. Only 11 aquatic invasive marine invertebrate, fish, and algal specifies have been identified in the NWHI.  The magnitude of the problem of aquatic invasive species is far greater in main Hawaiian Islands than in NWHI. Endemism and diversity in the NWHI has reportedly been higher than the main Hawaiian Islands for some corals and other reef species. However, the Northwestern Hawaiian Islands have not been free from human influence.

Early influence of man can be traced back approximately 1,000 years ago when Polynesians were the first to change the natural ecosystems of the islands. They brought to the main Hawaiian Islands animals such as boars, dogs and rats. However, the first documented evidence of mammals being introduced to the NWHI occurred in 1894 when entrepreneurs from a rabbit canning industry released rabbits that literally devoured all the vegetation on some islands; Laysan, Lisianski, and Southeast Island at Pearl and Hermes Atoll. Other alien or exotic plant and insect species (those that have been brought from other areas) drastically changed the existing ecosystems by destroying or out-competing many of the native endemic species. Until very recently the exotic Polynesian rats were major predators on Kure Atoll; eating the bird eggs and killing chicks. Today all the NWHI are completely rat free.

An old Coast Guard anchor sits deep within the Verbesina, a bright yellow flowering plant in the sunflower family that is an exotic, invasive plant on many of the atolls.
An old Coast Guard anchor sits deep within the Verbesina, a bright yellow flowering plant in the sunflower family that is an exotic, invasive plant on many of the atolls.

The Verbesina encelioides that we viewed on Kure Atoll; a bright yellow flowering plant in the sunflower family, is an excellent example of an exotic, invasive plant. This weed has literally suffocated and killed native plants as well as engulfed open space used as  nesting sites. Without weeding efforts by researchers, scientists and volunteers the birds would no longer have “runways” to allow the fledgings to run, take-off, and try their wings. Approximately 312 plant species have been identified on the NWHI. Thirty-seven species are indigenous, 12 endemic, the other remaining 267 are alien or exotic species.

Of the 485 species of insects and spiders found in the Northwestern Hawaiian Islands over 300 of them have been introduced by accident. Only 100 out of 485 are indigenous and another 80 are endemic. It is estimated over 20 new species of insects are introduced accidentally to mainland Hawai`i every year. This is just one reason why strict regulations are in place to minimize the introduction of new species to the NWHI. Exotic insects have devastating effects on the natural ecosystems. Ants on Kure Atoll have plagued the seabird chicks, who are relatively immobile during their early years and stay in the same nest area. Ants also displace native insects and can have such a major influence on ecosystems that they invade, or are introduced to, that they are called “ecosystem busters.”

In addition to the biological invasions, man has also brought other contaminants to the Northwestern Hawaiian Islands. Even though the area is thousands of miles from human inhabitation the islands remain impacted by man’s past military occupation. Kure Atoll is still recuperating from the remains of a Coast Guard station, LORAN tower and unlined dump site on the island. Contaminants may include elevated levels of copper, nickel, lead and polychlorinated biphenyls (PCB’s). Midway contamination from military operations include; petroleum, DDT, PCB’s, and heavy metals such as cadmium, lead and mercury. Over 75 million dollars were allocated by the Department of Defense for extensive clean up efforts on Midway Atoll just prior to the Naval Air Facility’s transfer to the U.S. Fish and Wildlife Service.

The remoteness of the area does not protect the islands from the prevailing ocean currents and man's trash.
The remoteness of the area does not protect the islands from the prevailing ocean currents and man’s trash.

During the Navy’s tenure at Midway,  in an effort to protect their pilots and aircraft, they would permit the deaths of thousands of albatrosses which are large enough to cause a danger to aircraft during landing or takeoff. In the short period 1957-58, over 36,000 birds were slaughtered and unknown thousands in subsequent years in an attempt to keep a major runway clear of albatross on Sand Island. When dead albatrosses began piling up on Midway, the commanding officer ordered them dumped at sea. However, with poetic justice, the prevailing currents carried an entire barge’s contents of rotting bird carcasses back to the beach at Midway and sailors had to pick them up and bury them.In the late 1800’s and early 1900’s the Northwestern Hawaiian Islands were exploited and ravished by seal hunters, whalers, feather hunters, pearl divers and guano miners. Seals, sea turtles, seabirds, sharks and whales were slaughtered en mass. In 1824 the ship Gambiamay have taken as many as 1,500 seals. The ship’s log of the Ada (1882) reported taking 103 sea turtles in just three days. Japanese feather hunters slaughtered thousands of seabirds. In the period from 1904 to 1915 counts of 284,000, 64,000, 119,000 and 200,000 dead birds and literally tons of feathers, were confiscated from Japanese poachers. These numbers represent only a fraction of the slaughter; only those who were caught poaching; many hundreds of thousands of bird deaths went undocumented and undetected.

The black-lipped pearl oyster (Pinctada margarifera) is one of the most obvious examples of the devastation man’s exploitation may cause. Masses of oyster beds were discovered at Pearl and Hermes in 1927. Within only three years of discovery estimates of over 200,000 oysters or 150,000 tons had been harvested and the oysters almost eliminated. An act was passed in 1929 making it illegal to take pearl oysters in Hawaiian waters. Later, in 1930, an expedition was sent to determine the extent of the damage to the oyster beds; only 480 oysters were found. By 1950 only six oysters were observed, and in 1969 only one oyster was found. More recent surveys in 1969, 1996, and 2000 found only a few oysters while a comprehensive 2003 NOAA study documented sightings of over 1,000 individual oysters. However, while the latter study suggests the oyster population may be starting to recover, almost 80 years have passed and the numbers do not begin to compare to the pre-exploitation levels. The pearl oyster clearly demonstrates the damage a coral reef can sustain from over-harvesting and the inordinate length of time it may take to recover even under full protection.

Fortunately, the entire reef is partially protected from many human influences by location and strict State and Federal restrictions. Existing in such a remote location the atolls and islands do not have the typical issues of coastal pollution and eutrophication from human inhabitation, tourism, development or agriculture like the main Hawaiian Islands. For the most part, the only humans to visit this isolated wilderness are researchers and scientists and they must sign and adhere to strict government permits and quarantines. All clothing or soft goods must be frozen for 48 hours to help prevent alien insects or seeds from going ashore. All dive gear must be soaked in a bleach solution after each use. Many varieties of fresh fruits and vegetables are forbidden on the islands.

However, the remoteness of the area does not protect the islands from the prevailing ocean currents and man’s trash. Currents in the North Pacific carry plastics and marine discards to the island shores. A portion of this debris may be terrestrial in origin while much of it obviously originates from fishing ships. As we walked along the shores of Kure Atoll we observed thousands of articles of domestic or household origin and items that were clearly from marine origins such as floats, nets, and other equipment connected with the industry. Based on past and current marine removal operations it is estimated that over 1,000 tons of debris has accumulated in the NWHI. Yearly accumulation rates are estimated at 40-80 tons. These amounts will continue indefinitely unless we educate and reduce the sources.

Legally, acts have been passed since the early 1900’s in attempts to protect the fragile creatures of the NWHI. Earliest efforts by Teddy Roosevelt (1909) attempted to protect the seabirds from the feather hunters by establishing the Hawaiian Islands Reservation. This reservation granted protections from Nihoa to Kure Atoll (minus Midway Atoll which at the time was owned by the U.S. military).  Since sea turtles travel from the NWHI to feeding grounds throughout the main Hawaiian Islands full protection did not occur until 1973 with the Endangered Species Act. Wild dolphins are protected under the Marine Mammal Protection Act, while the Hawaiian Monk Seals are protected under both the Endangered Species Act and the Marine Mammal Protection Act. The NWHI are of critical importance to monk seals and the sea turtles. The majority of the monk seals in existence live in the NWHI. Over 90% of green sea turtles depend upon the French Frigate Shores for their breeding grounds.  Researchers take surveys and collect information on the life cycles of the animals in an attempt to aid recovery of the populations and ensure that any of these species will not become extinct. Data is collected on monk seals, spinner dolphins, seabirds, and turtles by researchers in the NWHI.

Most recently, President Bush changed the designation of the marine area from a coral reef ecosystem reserve to include the islands as a Marine National Monument to effect more immediate change. By doing this the eight fishing permits that currently exist for the area will be phased out in five years and the entire Northwestern Hawaiian Islands will fall under more stringent long term protection.

However, legislation and presidential actions will not stop the debris that is carried from thousands of miles by ocean currents and deposited on the shores of these islands or correct some of the more subtle impacts of man that remain. We need to look deeply into the past, reflect upon our trespasses, and learn from our mistakes. Only education, protection and careful scrutiny of our environment and natural resources will accomplish this and provide future protection. Prevention is a better solution than attempts to clean-up. History tells us we must be better care-takers of our fragile coral ecosystems.

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Dena Deck, July 12, 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 12, 2006

A map integrating backscatter map with bathymetry, showing the seafloor in rich detail
Integrating backscatter with bathymetry, showing the seafloor in rich detail

Science and Technology Log

When soldiers from Napoleon’s army found the Rosetta Stone, it was a breakthrough discovery. Carved in ancient Egypt, it contained pieces of a message in known languages and also a language that had been dead for centuries. Without any link to other known languages, historians had been unable to decipher this language until the stone was found, which provided the necessary clues to translate it. Modern day ocean mappers are looking for their own Rosetta Stone that will allow them to link backscatter data to other ecological information.

A backscatter map, indicating substrate characteristics. Dark areas represent a harder seafloor, while lighter areas are indicative of a soft, sandy bottom.
A backscatter map, indicating substrate characteristics. Dark areas represent a harder seafloor, while lighter areas are indicative of a soft, sandy bottom.

Our ship, the NOAA ship Hi`ialakai, has a set of three sonars that, when used in conjunction, can provide accurate data about the seafloor. When emitted by a sonar, a “ping” comes back bringing two pieces of information with it: travel time and strength. The two-way travel time (the time it took from emission, bouncing off the seafloor and return back to the ship), coupled with the measured velocity of sound in the specific water location where the ship is traveling in, gives mappers a bathymetric view of the seafloor, revealing the depth of each of its points. (See “Painting the Seafloor” article.)

A second piece of data obtained from each ping is the strength of the signal. When sound hits a surface, above water or below, some of it is absorbed and the rest bounces back in what we experience as an echo. The strength of this echo depends on the hardness of the material that the sound is bouncing from. This is a very convenient fact of nature that is used when mapping to compliment the bathymetric map that provides the depth. The acoustic hardness of a substrate, or ocean bottom, affects the strength of the ping coming back to the sonar. In a real sense, the loudness of the echo changes if it is bouncing off sand or rock. Sand, being soft and full of small holes in between grains, will absorb quite a bit of sound. A more solid surface like a rock will provide a bigger echo for each ping that hits it.

A diver armed with a camera is towed from a boat, obtaining many pictures that will be used to groundtruth mapping data.
A diver armed with a camera is towed from a boat, obtaining many pictures that will be used to groundtruth mapping data.

This strength of the signal coming back is called “backscatter” and provides mappers with a second view of the seafloor. While bathymetry is a measure of the depth, backscatter gives us a clue about the nature of the seafloor being mapped. Since coral reefs, with their calcium carbonate, provide a much harder surface than a sandy sea bottom, the two will appear differently in the backscatter map. Values of intensity range from low intensity, showing up as white and representing soft, sandy bottom, to high intensity, represented as dark areas for harder substrate in the backscatter gray scale map.

When the backscatter map shows up binary data – white and black – it is easy to infer on the type of substrate being mapped. The challenge is presented with all of the gray areas in the map. Does light gray represent coarse sand? Is dark gray indicative of sand over rocks, or thousands of coral polyps? Or maybe just rock covered by sand? Every shade of gray has a value that can indicate a type of substrate.

Mapping
Mapping

Backscatter alone cannot give you these answers. With so many variables present in the mapping process, data needs to go through a “ground-truthing” process, or compared to visual observations of the sites. To do this, researchers collect video, photographs and perform actual dive observations of many of the sites that are mapped. These video and images need to be analyzed by a person. It’s a tedious process that cannot be automated – it requires having a person able to classify types of substrate from watching hour after hour of video data or many photographs. And all of these data needs to be “geo-rectified,” or coupled with GIS information to know exactly where each video segment and photograph was taken. Sometimes the payoff for “groundtruthing” backscatter is unexpected: wrecks or rich coral beds can be discovered.

We do not have yet a backscatter “signature” for each type of substrate, or sea bottom, yet. This would be the Rosetta Stone of mapping, a development which will allow mappers to correctly identify some of the ecological characteristics of each area mapped. For instance, mappers are working towards refining their backscatter analysis to allow them to tell apart live coral from bleached ones.

The NOAA Coral Reef Conservation Program has built a pilot data set from the French Frigate Shoals, consisting of large amounts of video footage, observations, and other data. They are in the process of compiling all of this information with their backscatter maps they have for the area, and study how they relate, trying to find meaning to each gray area in these maps.

When mapping, additional and unexpected discoveries can take place. Sometimes what we think of as featureless terrains are revealed to have rich topographies. In 2004, an ocean area off the island of Oahu in Hawai`i, thought to be featureless and plain, was discovered to have sand dunes and ridges, providing important habitat to the marine fauna. Interpretation of backscatter data has improved in quality over the years, and when combined with videos and photographs, remote characterization of sea floor habitats becomes possible.

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Dena Deck, July 11, 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 2, 2006

A NOAA ship using the sonar system.
A NOAA ship using the sonar system.

Science and Technology Log

The first part in appreciating what we have is to know exactly what we have to begin with. Biologists conduct species census in both terrestrial and marine environments, and spend a great deal of time studying each species. But to gain a fuller understanding of an ecosystem, it is also necessary to know the physical characteristics of the environment that provides the foundation for these ecosystems. This is one of the main reasons why we map the seafloor.

The primary goal, as far as mapping is concerned, is to have 100% of all shallow coral reefs mapped. The group mapping the Northwestern Hawaiian Islands is a large team comprised of staff from NOAA Fisheries Coral Reef Ecosystem Division, and the University of Hawai`i. They have an exemplary set of tools at their disposal to do their work. Aboard the NOAA shipHi`ialakai, they employ two sonar systems. Used in conjunction, these sonar systems are slowly giving us a detailed account of the submerged geological features that make up the Hawaiian archipelago.

A bathymetry map showing a 15-meter drop off from several angles. Colors indicate relative depth
A bathymetry map showing a 15-meter drop off from several angles. Colors indicate relative depth

The primary objective of this mission is to produce benthic (sea bottom) habitat mapping of Kure and Pearl & Hermes Atolls. We are filling in a doughnut-shaped gap on both Kure and Pearl & Hermes Atolls, finishing a painting of the seafloor that started several expeditions ago. Coral reefs around the world are receiving increased attention because of the many threats that they face (coastal development, overfishing, climate change), and the U.S. Coral Reef Task Force has produced a number of goals and mandates relating to these ecosystems in America. Among these goals is a call for better management of these resources, and to learn more about them. Mapping all U.S. coral reefs puts Hawai`i at the center stage of this effort with its large chain of islands and atolls stretching across vast distances and volcanic islands found at every stage of geological development, from birth to eventual demise.

The research vessel Ahi operating in Kure atoll. Note the AC cabin to operate the computer equipment required for the sonar.
The research vessel operating in Kure atoll.

The two sonars that we have aboard the ship perform the same task, but each is best suited to work in different conditions. That is because they employ different frequencies which have different rates of penetration. Let’s go back to the analogy of painting a wall. If you have a large wall to paint, you can use a broad brush (or even better, a roller), to cover large areas at every stroke. But within this wall you also have edges that need to be painted more carefully. Let’s say there is a light switch placed in the middle of the wall. Using a painting roller will invariably leave white spaces in between (either that, or you end up also painting the light switch!). So for this light switch, you would use a smaller brush, allowing you to carefully get close to it, eventually covering the entire surface of the wall without painting over it. In this analogy, each light switch in the wall represents an atoll of the archipelago.When a ship maps the ocean floor, it needs to slowly cover swath areas under it. The process is very much like painting a wall with a brush. A wall cannot be painted all at once, of course. The painting is accomplished one stroke at a time, where each passing of the brush needs to slightly overlap the previous one, as to not leave any white spaces in between. When mapping the seafloor, the ship, with its sonar as a giant brush, needs to carefully cover every bit of seafloor surface, as to not leave any area between passes, or swaths, blank and unmapped.

A recently completed bathymetry map superimposed with satellite imagery of Kure atoll. Red indicates lowest depth, and blue deepest. Satellite image has white around edge indicating the exposed reef ring.
A completed bathymetry map superimposed with satellite imagery of Kure atoll. Red indicates lowest depth, and blue deepest. White indicates exposed reef ring.

I am going to use the example of sunlight traveling through water to illustrate the way that the ship’s sonar works, both light and sound are waves.  Sunlight has many frequencies, frequencies that readily break out into all colors by raindrops or a prism. Red color has the highest frequency and, much like the 3002 kHz sonar, is the first absorbed by water. The color red is the first one to disappear underwater. Take anything cherry-colored down a few meters of water, and it will quickly loose all its brilliance, turning into a dull-looking color, an effect that is magnified with the scarcity of light at nighttime. Fish also know this very well. Many fish which are active at night tend to have a red color. Soldierfish, with their large eyes and flame-red color, are perfectly suited for the night environment.Painting over a light switch would mean running the ship into the reef! So mappers have a set of “ paint brushes” in the form of three sonars that allow them to carefully map each area. There is one low-frequency sonar (using a 300 Kilohertz (kHz) frequency) that has a long wavelength that can map between 100 meters (about 328 feet) and 4,000 meters (about 13,421 feet) – this is the ship’s big roller. There is another, high-frequency sonar (using a frequency of 3002 kHz) that can map when the seafloor is less than 100 meters (about 300 feet) from the surface – this is like a mid-sized brush. There is a third sonar, mounted on a smaller, 25-foot research vessel Ahi (which stands for Acoustic Habitat Investigator), with a sonar working at an even higher frequency, which can get really close to the reef – up to places which are 10 meters in depth (quite shallow, at 30 feet). This little boat is like the small brush used to cover areas right at the edge of what needs to be mapped.

Blue, at the other end of the visible light spectrum, has a low frequency. Its large wavelength is the last one to be absorbed by particles in the water, and penetrates deep in the ocean. If you are able to go down deep enough, say 100 meters (328 feet), all around you will look blue. I once went on a submarine ride with my sister, and when we reached 45 meters (150 feet) in depth, the entire inside of the submarine was bathed by blue light. I took her picture and, with no camera tricks, it showed how everything had acquired a sapphire hue (see picture).

When the pings return back to the ship from their very quick trip to the ocean floor, the sonar measures (or “listens”) to how long it takes for them to return, and how strong their signals are. To do this accurately, there are over 100 arrays of receivers in the sonar on the bottom of the ship, each carefully calibrated to listen carefully to each echo of a new ping. The pings coming back carry with them two bits of important information: how long they take (known as the “Two-Way Travel Time”) and the strength of the signal. The time it takes for the ping to return depends on how far it needs to travel (of course!) and how fast sound is traveling in the water.Now, how exactly does sonar work? The sonar unit emits sound, actually given the descriptive term of “ping.” This ping can be at either the low or high frequency described above. After the ping is emitted the sonar unit “listens” for it to come back. Sonar, therefore, has two essential components: the first one that emits the ping, and the second one that listens for it coming back from the seafloor. This is because when sound hits a surface, some of it is absorbed while the rest bounces back. (If you have many large walls around you, you can hear almost all of your sound coming back at you, this is the echo you hear.) The denser, and flatter the surface, the more of the sound that bounces back.

Adding a bit of complexity to this process, the speed of sound is not immutable like the speed of light. In water, it depends on the temperature of the water, its salinity, and depth (all of them affecting the density of water), so careful and constant measurements need to be taken regularly. A large array of devices, collectively known as CTD, are routinely lowered from the main ship into the water. Armed with this information, and by carefully measuring the time it took for the ping to complete its travel, we can know how far each ping had to go. If you do this many times over, you have something called “bathymetry,” a picture of the seafloor.

Putting together shallow and deep water mapping, we soon end up with a seafloor that has been completely painted, full of colors representing depths. An accurate map is essential as a base layer upon which other information can be overlaid, such as bottom cover type – coral, rocks, sand, etc. Mapping, combined with bottom characterization allows us to monitor long-term trends and changes in the marine habitat. This long-term observation is an essential tool for management of the resources. It can serve as one of the indicators for the effectiveness of the conservation efforts, allowing us to make “sound” management decisions.

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Patricia Greene, July 7, 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 7, 2006

Science and Technology Log

The majority of the Hawaiian monk seals are found in the Northwestern Hawaiian Islands from Nihoa Island to Kure Atoll with a small number on the main Hawaiian Islands.  Traditionally Monk seals have been killed for food by early sailors.  The species was declared depleted under the Marine Mammal Protection Act in 1976 following a 50% decline in beach counts.  Monk seals were also classified as “endangered” under the Endangered Species act in 1976.  Undersized female pups from the French Frigate Shoals were rehabilitated and released on Kure from the 1980’s until 1995 in an attempt to re-establish populations.

Most pups are born between February and July with the peak in April and May.  The newly born pup is totally black and weighs approximately 20 to 30 lbs.  By the time they are weaned (30 to 40 days) they will increase their weight to over 100 lbs.  Monk seals in the Northwestern Hawaiian Islands tend to wean their pups sooner at approximately 30 days, while seals on the Hawaiian Islands tend to nurse longer; as many as 60 days. Northwestern Hawaiian Island pups tend to be smaller in size as a result.  Females give birth on beaches with shallow water to protect their pups from sharks.  A female will not give birth until they reach five to ten years of age.  By the time the researchers arrive on Green Island most female seals will have already pupped.Approximately 90% of the monk seals remain at the island where they were born for life.  During our recent visit to Green Island, I interviewed monk seal researchers Tracy Wurth and Antonette Gutierrez from the National Marine Fisheries Service.  Tracy and Antonette have been in the field on Green Island since May 16, 2006 collecting data on the monk seal population.

Field researchers from the National Marine Fisheries Service on all the Northwestern Hawaiian Islands keep careful track of each seal in the colony; identifying individuals with applied tags and bleach marks as well as natural markings or scars.  Every seal is photographed by taking photos of all sides and flippers and are documented in a digital photo library.  New pups are tagged as soon as they are weaned at 30 to 40 days.  Plastic “temple” tags are applied to each rear flipper and injected with a micro-chip pit tag.  Flipper tags are color specific to each island; Kure uses grey tags, while Pearl and Hermes uses light blue tags.  The letter assigned will tell researchers what year the pup was born.  One pup with a bleach mark “Z26” swam close enough to our boat for us to read his marks.  Later the researchers knew exactly what seal we had seen and told us it was a “weaner;” a pup born is this year that had already weaned.Tracy and Antonette conduct seal patrols on Green Island on a daily basis.  They walk the beach collecting information on each seal observed.  Approximately every fourth day they conduct an atoll count, which is a standardized seal patrol that is time sensitive and basically captures a “snapshot” of the population at a given time.  For their atoll counts the seal team start their survey on Green Island at 1:00 pm and when finished take their boat to Sand islet and conduct a survey there.  Atoll counts take the researchers approximately three hours.

Researchers also collect marine debris such as nets on shore or in shallow water and move it to a secure location to be picked up at a later date by the National Marine Fisheries Coral Reef Ecosystem Division.  The collection of marine debris is extremely important because monk seals can become entangled in the nets.During the field season information is collected on injuries, wounds, illnesses, abnormalities, as well as deaths/disappearances, births, and any unusual events.  If a dead seal is found a necropsy is performed and samples from organs and tissues are collected.  Researchers also collect specimens of scat and spew (vomitus) in an effort to analyze the monk seal’s diet.  Tissue plugs are taken from tagged pups for DNA analysis to determine maternity.  Priorities for the Kure researchers include all of the above, while male aggression and shark predation mitigation is not a significant problem here at Kure Atoll.  However, researchers are concerned about the future seal population due to low juvenile survival.  As the current breeding females get older or die there will not be younger seals to take their place in the breeding population.

At Kure Atoll, the adult seal population in 2005 was 86 individuals with 23 pups born.  The population at Kure has been slowly decreasing over the last several years.  One major factor is the low juvenile survival rate due to lack of nutrients and resulting emaciation.  However, this year their numbers show an increase in juvenile survival with a re-sight rate of over 60 percent.  In the past the re-sight rate has been closer to only 30 percent.

While on Kure Atoll, the researchers enter their data in the field database system. When the researchers return from their assignment they will file their final report.  This information will be summarized in published papers and used by various institutions such as the Hawaiian Monk Seal Recovery Team.

The future of the protected monk seal is unclear. Today, researchers estimate the total monk seal population in existence is approximately 1,300 to 1,600 seals. Researchers are concerned if the population continues to decline the total number could fall below 1,000 within the next five years. Scientists and researchers work together to find solutions to aid the recovery of the Hawaiian monk seal.

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Patricia Greene, July 6, 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 6, 2006

Science and Technology Log

We arrived on Green Island at Kure Atoll and observed thousands of Laysan Albatross, (Phoebastria immutabilis),chicks and fledglings.  As we walked the island we noted dead birds among the living.  To some extent this may be a natural occurrence.  Only one egg is laid and both parents nurture the chick.  In the early stages the parents return often with frequent feedings.  As the chick matures and becomes older the feedings become less frequent; at this age perhaps just once a week.  The parents may travel hundreds, even thousands of miles across the Pacific Ocean far as the Aleutian Islands to forage.  Meanwhile, the chicks wait close to their hatching spot for a parent to return.

In a perfect world untainted by man, our chick’s diet would consist of fish and fish eggs, squid, and octopus.  Yet in our world and the “age of plastics” the chick will likely be fed some amazing indigestible, synthetic products. The parent albatross has a perilous journey.  On the way one or both of parents may fall victim to long line fishing or nets, power lines, planes, sharks or other predators.  If one parent is killed, the other parent will probably not be able to provide enough food to sustain the chick; the chick will sit and wait for the parents; eventually starve to death, or if it is old enough and ready, it may try its wings and fledge.

Although a chick may be fed plastics, once they reach fledgling age they are usually able to regurgitate the indigestible material and cleanse their bodies of the plastic.  However, if the pieces are too large or in this case, large, sharp and piercing, the bird may die an agonizing death; totally impacted and/or the lining punctured.  As we walked the paths of Green Island we observed many young dead albatross.  After viewing this incredible necropsy we contemplate how many of these young birds may have met a similar fate to the one we necropsied.  Our specimen was chosen at random, selected only because we realized it had died within the last few hours.On July 1, 2006, Cynthia Vanderlip conducted a necropsy of a chick that had expired a few hours previous.  The “chick” had a wing spread of 5 to 6 feet and weighed approximately 5 lbs.  The contents of the bird’s stomach amazed and shocked the teachers and scientists.  The dead chick was severely impacted and literally full of plastics.  Some pieces were approximately 6 inches long and several were sharp and jagged.  We could conclusively state this bird was killed by the plastic debris because of the observed puncture in the lining of the proventriculus.  We removed the plastic from our bird and counted an excess of 306 pieces of plastic!

Typically, Laysan Albatrosses have a larger volume of ingested plastic than any other seabird because their favored food, flying fish eggs, are attached to floating debris, and in our modern world most of this debris is plastics, where it used to be wood or pumice.  Floating is one of the properties of plastics.  The most recent research that we had available to us on the island regarding plastics and albatross chicks was published in 1995.  According to this research by Auman, Ludwig, Geis, and Colburn: “ingested plastic probably does not cause a significant direct mortality in Laysan Albatross chicks, but likely causes physiological stress as a result of satiation and mechanical blockage.  Resulting problems may include; starvation, suppressed appetite, reduced growth rate, lower fledgling masses, obstruction of the gut, and decreased fat deposition.”

Interestingly, much of the plastic found in the Northwestern Hawaiian Islands is of Japanese origin.  As we walked the beach we observed many plastic articles with Japanese writing on them.  In the boli from chicks we observed Japanese cigarette lighters and in our specimen there was a piece of plastic with Japanese writing on it.  Some of the debris may be from Japanese fishing boats or perhaps from the warm Kuroshiro current that flows from Japan.Research suggests there is an upward trend in the volume and mass of plastics found in the Laysan Albatross chicks.  In 1966, 74% of 91 chicks contained some plastic, with 8 pieces being the greatest number found and the average mass only 1.87 grams.  In the 1994/1995 study 18.1 grams and 23.8 grams respectively.  From our recent experience, we could only imagine what the numbers look like now in 2006.

In a few days, our bird will be gone; devoured by the decomposers and scavengers.  At night the ghost crabs will come out of their burrows and feast on him; beetles and fly larvae will clean up the remains.  Soon the bird will be reduced to just a pile of feathers but the plastics we found will remain for years.Another concern is when the albatross eats burned or melted plastic parts.  These are especially toxic because of release of organochlorines; polychlorinated biphenyls (PCB’s) and phospholipid foams, which can be absorbed and harmful to both the adult birds and their chicks.  Many pieces of burnt plastics were observed on the island and in the chick Cynthia conducted a necropsy on.