Monthly Archives: June 2006

Brenton Burnett, June 30, 2006

Posted on by Teacher at Sea

NOAA Teacher at Sea
Brenton Burnett
Onboard NOAA Ship David Starr Jordan
June 26 – July 6, 2006

Mission: Shark Abundance Survey
Geographical Area: California Coast
Date: June 30, 2006

Weather Data from Bridge 
Visibility:  10 nautical miles (nm)
Wind direction:  250 degrees
Wind speed:  9 kts
Sea wave height: <1
Swell wave height: 1-2’
Seawater temperature: 17.6 degrees C
Sea level pressure:  1015 mb
Cloud cover: Clear

Russ Vetter and Rand Rasmussen position a blue shark so they can measure its length and remove the hook.

Russ Vetter and Rand Rasmussen position a blue shark so they can measure its length and remove the hook.

Science and Technology Log 

Today was a slower day in terms of numbers of sharks—we only caught three. But the mood was good because each of the sharks caught was large enough to accommodate satellite tags.  And, we caught one of each species of shark that we anticipate seeing—a blue, a thresher and a mako.  The mako was particularly lively giving a good kick as it left the shark trough. Any of the sharks tagged on this trip, or others in the same effort, can be monitored here. On this cruise we have attached SPOT tags to two makos (on Tuesday #60986 and today, #60998), a blue (#60989) and a thresher (#53797). Note: I’m told that all four of these MAY be listed as blues on the website until the website is fully updated, but the tracks of all four sharks should be viewable right now!

All sharks are in the phylum Chordata.  They, along with rays and skates, and a strange and even more ancient group of fish called chimera, make up Class Chondrichthyes, which are the fish with skeletons made of cartilage.  The only bony material in a shark is its teeth and for this reason very few shark fossils beyond teeth are found.  The other classes of chordates are the jawless fishes (hagfish and lamprey), the bony fishes (minnows, mola, cod, seahorses, etc.), amphibians, reptiles, mammals and birds.

The goblin shark—perhaps the ugliest shark ever!

The goblin shark—perhaps the ugliest shark ever!

Each class is divided up into orders, and there are eight orders of sharks— one order includes the sawsharks, another the whale shark and wobbegong, and another the angelsharks (which have some resemblance to rays).  The frilled and cow sharks make up another order, the bullhead sharks another, and there is an order for the dogfish sharks (including the spiny dogfish which might be the most numerous of all shark species—closer to shore, we may hook one).  All of these orders are sharks but when people think of sharks they typically envision either mackeral sharks, which include great whites, makos, tigers and threshers, or the ground sharks, which include leopard sharks, hammerheads and blue sharks.

The 16 species of mackeral sharks are among the most specialized of sharks. Many, like the mako, are swift swimmers.  Threshers have a tail that is as long as the rest of their body is. It is believed that they use this tail to “corral” fish and then slap the fish to stun them.  The goblin shark lives in the dark of the deep and has a strange snout jaw structure that makes it arguably the ugliest shark.  The first of these was caught in 1897 near Japan.  A scientist there delivered it to Professor David Starr Jordan, for whom the National Oceanic and Atmospheric Administration ship we are on is named.

The DAVID STARR JORDAN awaits the return of its Zodiac boat.

The ship awaits the return of its Zodiac boat.

With over 200 species, the ground sharks are the most diverse and varied order of sharks. The blue shark is a generalist living in open waters in nearly all of the world’s oceans. Others, like the catsharks are benthic, or bottom-dwelling.  Most are small and harmless but some are the largest of predatory sharks. All of them have what’s called a nictitating eyelid which covers the eyes to protect them as the shark bites.

Personal Log 

During today’s afternoon set, we inadvertently lost a buoy that was intended to be clipped to the longline. Fortunately, such a mishap is occasion to let loose the ship’s two engine Zodiac.  Myself, Stephanie Snyder (an intern with NOAA), Miguel Olvera, and crewmembers Chico Gomez and David Gothan, set out to retrieve it.  The buoy was dropped early in the set so we had to travel a couple miles out.  On the way, we briefly saw four molas.  Later a sea lion passed by.

An adventure here, an adventure there—the fifth day is as interesting as the first!

Chris Harvey, June 30, 2006

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NOAA Teacher at Sea
Chris Harvey
Onboard NOAA Ship Oscar Elton Sette
June 5 – July 4, 2006

Mission: Lobster Survey
Geographical Area: Central Pacific Ocean, Hawaii
Date: June 30, 2006

Science and Technology Log

“Finish well.”

-Terry Harvey, my mother

-Larry Harvey, my father

(Strange they both offer the same advice!)

Everyone’s spirits seem to be up this afternoon, for good reason. The work is finally done and we are on our way back to Honolulu! The last two days I have risen from my sleepless sleep before sunrise to drink a cup of tea before work. Recently the sunrises have paled in comparison to the sunsets, and have been followed by an inundation of rain at the same time we were set to begin hauling traps. Yesterday there was lightning and thunder so heavy that some people were actually hesitant to go outside. I cooed a gentle sigh at the sign the thunderstorm, as it was a friendly reminder of summer back home in Jacksonville. It rains hard every day for about an hour around 4-5 in the afternoon, and I usually find a way to curl up in bed and listen to the storm outside. After that, the skies clear and life goes on.

We worked through the rain both mornings. From my position yesterday as a cracker I was forced to wear foul weather gear to keep me warm and dry underneath. Again, images of an orange Gumby come to mind. But it worked and, despite the rain, we finished on time. Today I ran traps between the crackers and the stackers, though I accepted the cool rain as refreshment instead of something to be avoided.

Being on the subject of finishing, I always use the quote, “Finish well” near the beginning of the semester to try to get my kids focused on the idea of completing a task to the best of their ability. I find from my own experience, as my mother constantly reminds me, I have always struggled with the idea of finishing well. Usually I find that the last part of any given task is the hardest. Most commonly, this final segment of work is the cleaning up part. And who likes to clean up anything?

It is fun to start projects. Everyone loves a fresh chance to earn good grades, do well in an athletic season, or learn how to perform well at a new job. But very few of us enjoy finishing a semester that we did not do particularly well in, participating in an athletic event that does not matter whether we win or lose, or finishing up those last two weeks after we have put in notice of quitting a job.

Those tend to be the hardest moments, in my opinion, because our heart is no longer in whatever we are doing. If we are finishing a mediocre semester of school, our mind is either on the break between semesters or on the next semester already. If we are playing in that last sporting event and we have no chance of going into the postseason, we are probably thinking about how much free time we will have available to us or how we will begin preparing for the next season. In quitting one job, most of us would already have our minds set on our next job, or at least be thinking about how to make ends meet in the time between jobs.

So I remind my kids at the very onset of the semester, especially in the fall when they are beginning their first year of high school, to finish well. Although they have four months between the first and last day of class, each day in between contributes to whether or not they finish the semester well. Franklin Covey would tell you to “Begin with the end in Mind.” In either case, it is good to think about how you plan to finish a particular task. If you plan on finishing poorly, what is the point of even beginning the undertaking in the first place?

We are nearing the end of this cruise and have completed most of the hard work. However, there are still three days separating us from land and there are still the tasks of cleaning up and packing. Already I have found myself in denial of the fact that we still have to clean up. Kenji, our chief bosun, blasted an air horn when we hauled in the last buoy. Everyone in the pit let out their own sigh, or scream, of relief at having finished our hauling for the trip, and then cleaned up and went to lunch. I was content to let this cruise be finished, and to take these last three days as the beginning of my summer vacation. Yet as I sat in the galley eating lunch, the sound of my mother’s voice came to my head. “Finish well,” she said.

We have agreed to take the rest of the afternoon off and finish cleaning everything up tomorrow. That is good because no one is in the mood to work now anyway. The sun is finally shining outside and I think I will go take a nap in its rays, listening to my music, and thinking about nothing in particular.

Brenton Burnett, June 29, 2006

Posted on by Teacher at Sea

NOAA Teacher at Sea
Brenton Burnett
Onboard NOAA Ship David Starr Jordan
June 26 – July 6, 2006

Mission: Shark Abundance Survey
Geographical Area: California Coast
Date: June 29, 2006

Weather Data from Bridge 
Visibility:  10 nautical miles (nm)
Wind direction:  306 degrees
Wind speed:  15 kts
Sea wave height: 1-2’
Swell wave height: 2-3’
Seawater temperature: 19.8 degrees C
Sea level pressure:  1017 mb
Cloud cover: Partly cloudy

The beaks of a variety of squids and a fisheye lens found in a blue shark’s stomach.

The beaks of a variety of squids and a fisheye lens found in a blue shark’s stomach.

Science and Technology Log 

While today’s catches were lighter than yesterday’s, there were some very interesting new sights to see. One blue shark that made it up on deck, threw up some of its stomach contents.  Out came the remains of a pelagic (open water) crab and a number of squid beaks. The largest of these beaks was three centimeters (just over an inch) in diameter and the smallest less than a half a centimeter. Blue sharks are perhaps the most widely distributed shark, living in all oceans except in the polar latitudes. As such, they are generalists and eat squid, fish, smaller sharks and even birds. Jacques Cousteau even filmed blues shepherding virtually invisible krill into balled clusters so they could swim through the ball to feast. While setting the afternoon line, I saw a curved tip dorsal fin break the surface off the starboard bow. Then it disappeared under a wave.  Moments later as we caught up to it, a large disc of a fish could be seen below the fin—a mola!!  Molas are the largest bony fish though they are not the largest of all fishes. That honor belongs to the docile plankton-eating whale shark. Molas can reach a length over 4 m (13 feet), though the one we saw was closer to 2 m (6 feet).  Whale sharks, however, can grow to over 20 m (70 feet) long.

Bottlenose dolphins porpoising in front of the bow of the DAVID STARR JORDAN.

Bottlenose dolphins porpoising in front of the bow

Later, as we hauled the afternoon set, another mild surprise—a pelagic stingray was caught on our line! Once aboard, the highest priority was to disarm the poisonous spine projecting from the base of the stingray’s tail.  While Sean Suk, another Southwest Fisheries Science Center (SWFSC) researcher, held the ray down, Suzy Kohin was able to clip the spine disabling the ray, but not harming it. Rays and skates evolved flattened bodies as an adaptation as benthic, or bottom feeders. Rays and skates, or batoids as they are called collectively, have a mouth positioned on the bottoms of their bodies so they can best feed along the bottom of the ocean. Pelagic rays, as their name implies, live in the open ocean. So the pelagic ray has evolved a unique style of feeding. When approaching a school of fish, this ray will turn upside down and curl its wings above it forming a funnel.  This funnel shape directs the fish right to its mouth.

In the evening, after our work was done for the day, a few of us were on the stern deck when a school of dolphins approached. Soon they surrounded the ship and a group of six or seven stayed with us porpoising at our bow for close to thirty minutes!  “Porpoising” is the arched jumping above the water as dolphins swim. This behavior allows these mammals to breathe while maintaining their pace.  Porpoising should not be confused with breaching which is a more vertical jump from the water. Breaching behavior has been observed in a number of whale species, but also in some sharks.  The two shark species best known for breaching happen to be the two species we are most interested in on this cruise—makos and threshers.  Scientists are not certain why whales breach, nor are they entirely certain why sharks breach.  At least a partial answer may be that they are making an attack on prey.  Many sharks, not just blues, are known to eat sea birds, and makos, specifically, have been seen jumping from the water in attempts to attack floating sea birds. White sharks, the larger cousins of makos, are known to breach but in False Bay near Dyer Island off South Africa, this behavior could even be described as common.  The unique seafloor topography there forces the southern fur seals to repeatedly swim from surface to seafloor as they make their way to the island (if they didn’t they would be eaten by the sharks outright). Researchers have discovered that as the great whites pursue the seals from the depths their momentum takes them up and fully out of the water in spectacular breaches.

Personal Log 

Every day on board brings something new to this mountain man.  On deck, when critters aren’t appearing on board or in the sea, there are always science folks to answer questions. Of course, that is when they aren’t watching World Cup soccer via the satellite TV.  ‘Til, tomorrow…

Brenton Burnett, June 28, 2006

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NOAA Teacher at Sea
Brenton Burnett
Onboard NOAA Ship David Starr Jordan
June 26 – July 6, 2006

Mission: Shark Abundance Survey
Geographical Area: California Coast
Date: June 28, 2006

Weather Data from Bridge 
Visibility:  10 nautical miles (nm)
Wind direction: 300 degrees
Wind speed:  17 kts
Sea wave height: 2-3’
Swell wave height: 3’
Seawater temperature: 19.6 degrees C
Sea level pressure:  1015 mb
Cloud cover: Scattered clouds

A National Marine Fisheries Service (NMFS) tag and insertion tool.

NOAA Fisheries tag and insertion tool

Science and Technology Log 

Dr. Kohin, our chief scientist, tapped me to assist on the shark platform this morning!  This means I helped remove the hook from sharks’ mouths and helped with the tagging.  Note: I didn’t get bit once nor was I lost overboard.  And the sharks did well, too. There are many tasks that lead up to shark tagging and hook removal.  As the long line is drawn in by electric winch, one member of the science team unclips the gangion (or the buoy) and passes it on to others for stowing. If no catch was made on that hook (which is the case most of the time), the bait has to be removed before stowing.  If there is a shark, however, it is walked “on its leash” to the stern (back) of the ship to the shark platform where Russ Vetter and Rand Rasmussen  (and often Suzy Kohin though she is also busy coordinating the efforts of everyone) work to collect data and release the animal.  Others record data and provide the materials necessary for tagging.  As is often the case when conducting scientific research, much of this work can be repetitive.  But when something comes in on the line, or when something unexpected happens like when a gangion is twisted on a line, there is lots of activity and excitement.

A ROTO tag clamp.

A ROTO tag clamp.

To be sure, the most excitement is on the shark platform.  This 4 foot by 8 foot (approximate) platform is connected along its long side to the shark trough. The shark platform is accessed from the deck by a large chute that is as wide as the platform is long.

The shark trough is lowered just under the water until the shark (still on the line) can be maneuvered into the shark trough by Russ.  Once there, Russ and Rand are quick to hold down the shark so that they can safely work on it.  Rand uses a small thick blanket to cover the shark’s mouth and sharp teeth.  Before releasing the animal, however, he needs to remove the hook.  While the two of them hold the shark, another person (which was me this morning) cuts the hook or wire lead. By this time the sex of the shark has been determined.  This is easily accomplished by observing the rear underside of the shark— two finger like “claspers” near the pelvic fins are present if the shark is a male.  The last step before releasing the shark is to measure its length.  A meter stick along the edge of the trough makes this an easy task.

SPOT tags being programmed for use.

SPOT tags being programmed for use.

If the shark is a mako or a thresher, however, a number of other tasks are undertaken before hook removal and release of the shark. First, a National Marine Fisheries Service (NMFS)”spaghetti tag” is attached just forward and to the side of the dorsal fin. These are “conventional tags” which give the animal a number and provide an address to send the tag to if the animal were recaught.  The spaghetti tag is barely more than a plastic wire attached to a pointed piece of metal.  To insert it, a small incision is first made in the shark’s back.  Then, using an awl shaped tool, the metallic portion of the tag is wedged through the incision just under the skin. Because these tags may not stay in for life, a backup tag is also used.  These are called ROTO tags and they are attached directly to the dorsal fin. Sharks returned with ROTO tags also indicate to researchers that oxytetracycline has been injected into the shark. These tags, like others, contain reward information for the return of specimens or information about them.

For larger and healthier sharks, satellite tags, of which there are two, may be attached to the shark. The SPOT tag (smart position and temperature tag) is a bit thinner and smaller than a computer mouse.  Attached to the dorsal fin (in lieu of the ROTO tag), the SPOT tag has two metal washers on its exterior.  If the shark rises to the surface, with its dorsal fin out of the water, these washers dry long enough to disrupt the electrical current that normally passes between them through the water.  This cues the tag to transmit the shark’s position to a satellite.  Using these tags costs more than $2,000 each, so it is important to use them with animals that are large enough to receive them and ones who are in good health.

PAT tags ready for use.

PAT tags ready for use.

If a shark receives a SPOT tag, a PAT tag (popoff and archival tag) will also be attached. The PAT tag records water temperature, depth and light levels at one minute intervals. After a few months or some other specified time, the tag is designed to pop off and float to the surface.  At that time the tag transmits a summary of its data collection to researchers via satellite.  If the PAT tag can actually be recovered, the full set of data at its full resolution can be retrieved.

It is interesting to note that light levels act as a proxy for time of day given that noon and midnight can easily be determined from them.  And, in turn, this information can be translated into a longitudinal position as one notes the shift of day time from the location of tagging. Light level can also be used to determine latitude as on all days except those nearest the equinoxes, the length of day is dependent upon how far one is north or south.

Between the SPOT and PAT tags, the horizontal as well as vertical movement of the animal can be tracked over a period of time.  Using only conventional tags, only one additional location can be mapped, and that only with a recatching of the animal. With these methods, it is hoped that the travels of these young makos and threshers, will be better understood as they feed and breed.

Personal Log 

Every day has been exciting, but today helping on the shark platform has topped it all.  I was lucky, too, as that set was the most productive, so far.  We caught 57 sharks on 202 hooks—a pretty good batting average.  And five of these were makos.  We also caught a larger thresher shark, rare out this far.  I was thrilled to think I’d get to see this guy up close, but alas it was not to be. The thresher threw the hook and escaped—the big one got away! Fortunately, later in the trip we’ll likely be more in thresher waters!

Patricia Greene, June 28, 2006

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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: June 28, 2006

Science and Technology Log

We awoke with anticipation at approximately 5:30 a.m.  Today we were scheduled to arrive at Kure Atoll and with any luck would have our first snorkel experience in the Northwestern Hawaiian Islands.  We have been in transit twenty-four hours a day for six days onboard the NOAA Ship Hi’ialakai.  We have covered a distance equal to traveling from Houston, Texas to Reno, Nevada.

Our snorkel gear is placed on deck near the loading area at 6:45 a.m. and after a quick breakfast we go up on deck with anticipation of our first view of Kure’s Green Island.  Two shade trees are in the middle of the island and appropriately a rainbow drapes the north end.  Birds; albatrosses, terns, and frigate birds fly out to greet us, while spinner dolphins play in the spray at the bow of our ship.  What an awesome welcome!

At last we are instructed to load and we pull away from the Hi’ialakai, excited and anxious to see this underwater realm that we have all been reading, researching and immersed in the last six days while transiting.At 7:30 a.m. the dive and snorkel team meet on the fantail and receive one last safety meeting from the Chief Boatswain and Dive Saftey Officer, Mark L. O’Conner.  Protocol on the ship is that the Maritime Archeology dive boat, the H1, is loaded first with supplies and people then lowered by crane into the ocean.  Next the research vessel Ahiwith the University of Hawaii and NOAA mapping crew will enter the water, also by hydraulics.  Lastly our snorkeling boat, an inflatable zodiac with a 50hp 4 stroke will be placed in the water.  The only difference is our boat is not loaded so therefore we pass supplies into the boat and then we will need to climb down a Jacob’s ladder on the side of the Hi’ialakai in order to enter the boat.

Our first reward is the sight of a Hawaiian monk seal on one of the sand spits.  Ordinary Seaman, Jason Kehn, our coxswain, is careful to take the boat far around the area so as to not disturb this rare, endangered species.  The monk seal is apparently oblivious to our presence and only when we see a flipper move and his head rise, are we sure he is not dead.

After last minute safety instructions and advice to “look predators in the eye,” we are ready to enter the reefs.  The water around us is a collage of vibrant shades of blue and turquoise.  We open our eyes and are surrounded immediately by a huge school of chubs; seemingly curious and unafraid of us.  The visibility is phenomenal, probably 80ft.; the water crystal clear with no turbidity.Jason competently maneuvers to our dive site; we are grateful that he knows the area because our GPS is telling us we are still 21 miles from the site! We tie up to a CREWS (Coral Reef Early Warning System) buoy; one that transmits temperature, turbidity, and other environmental data that can detect significant impacts to the coral reef ecosystem.

Fishes are numerous in Kure Atoll’s lagoon. Smaller species dominated our survey area. This may be explained by the coral reef habitat.  Coral cover was around 80 percent, with finger coral (Porites compressa) being the dominant species.  Living finger coral provides many hiding holes for the juveniles and adults of smaller species, and this may be the reason for the great abundance of smaller species of fish.

Ellyn, our naturalist from Hawai`i, observed that overall there is greater diversity in the fish species in the NWHI than on the main Hawaiian Islands, however, in general the fish were smaller in size for their species.  Patty, our Teacher-at-Sea from the Florida Keys noted that overall the coral appeared much healthier that many of the reefs in the keys and noted the absence of the soft corals and brain coral so common in the keys. Finger coral may be an endemic species and is quick growing, often out competing other coral species for space.  Massive continuous heads created yards of living reef on our survey site.  We observed that the sheer weight of the massive heads often forced large pieces of living reef to break off and form rubble fields below the living reef.  These rubble fields provide highly desirable substrate onto which other species of corals recruit and create many tiny hiding holes, very desirable homes for larval fish to recruit into from the water column.  Homes for the adults, homes for the recruiting juveniles…what a perfect place to live!

Jessica Schwarz, June 28, 2006

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NOAA Teacher at Sea
Jessica Schwarz
Onboard NOAA Ship Rainier
June 19 – July 1, 2006

Mission: Hydrographic Survey
Geographical Area: Alaska
Date: June 28, 2006

The ship is underway, heading across the Gulf for Kodiak and to be honest the more I type the queasier my stomach feels so I’m keeping this entry short.

The seas are not rough today, I think they said between 5-7ft. swells, but the rocking of the ship has me feeling sick to my stomach a little bit.  I guess the more time you spend up top of the ship, the worse you might feel.

I went up to see the action in the bridge while we’re underway.  Able-Bodied Seaman (AB) Leslie Abramson let me take the helm for a few minutes.  There are several compasses to watch, basically all at one time, telling you the course you are on as well as your degrees of course change. Since we are in open ocean there were no useful landmarks to point towards to help me stay on course.  It was a very neat experience to be at the helm of the RAINIER.  She is a huge ship and it’s pretty incredible to feel her move with such small turns of the helm.

Okay, that’s all I’ve got. I’m not feeling too well and probably should find some motion sickness medication.  I’m eating my words of my last log and caving.  I’ve decided being a zombie beats feeling sick.

Just so ya know 

I threw up my dinner after finishing this log and with the garbage can at my bedside I slept quite well.  So, even after having taken sea sickness medication, I’m still puking…what’s up with that?  I guess there’s just no preventing these things  sometimes.

Brenton Burnett, June 27, 2006

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NOAA Teacher at Sea
Brenton Burnett
Onboard NOAA Ship David Starr Jordan
June 26 – July 6, 2006

Mission: Shark Abundance Survey
Geographical Area: California Coast
Date: June 27, 2006

Weather Data from Bridge 
Visibility: 10 nautical miles (nm)
Wind direction: 350 degrees
Wind speed: 9 kts
Sea wave height: 1’
Swell wave height: 2-3’
Seawater temperature: 20.0 degrees C
Sea level pressure: 1012.7 mb
Cloud cover: Cloudy

The mako sharks we catch are one to two years old and are between 70 cm and 140 cm (around 3 feet) long.

The mako sharks we catch are one to two years old and are between 70 cm and 140 cm (around 3 feet) long.

Science and Technology Log 

Our first full day of setting and hauling netted 68 sharks. In the morning we caught 21 blues and 5 makos, and in the afternoon 39 blues and 3 makos.  Unfortunately, one mako and one blue did not survive and were brought aboard for sample collections.  Though everyone involved understands that the work being done here is ultimately about helping these sharks survive and thrive in the wild even when an animal dies, there is, among everyone, a definite sense of loss and regret when an animal is lost. The data collection process involves a great deal of care for that reason.

Studies have been done to look at the stress related hormone levels of sharks caught on long lines, and the length of “soak times” used in this project follow those recommended guidelines—three to four hours from the start time of setting the line to the start of hauling it in. The design of long line helps to maximize survival, too. The gangions, which are the lead and hook assembly that attach to the long line, are about three meters long which gives these sharks room to swim while hooked.  This is important for blues and makos as they, like many other sharks, need to keep in constant motion so fresh, oxygen-rich water is always moving through their gills.

Another challenge is that, on occasion, a shark will swallow the hook, so whenever possible a “circle hook” is used that will not hook in the stomach or esophagus, but only on a “corner” of some kind.  If a circle hook is swallowed it will get pulled out by the shark’s movement away from the line but when the animal turns away, the circle hook will catch in its mouth.  Even if a hook, like a J-hook, cannot be removed from an animal because it was swallowed, this does not necessarily mean it will die.  Sharks with hooks in them have been released and recaught years later. When a shark does die, its body is utilized to understand sharks better.  This is especially true for the mako sharks.  Dr. Jeff Graham and two of his students, Dovi Kacev and Noah Ben-Aderet, as well as Miguel Olvera, another graduate student, are collecting a number of tissue samples for themselves and others at their home universities.

The gills of the mako sharks are of interest because makos are a high-performance, speedy, shark. A comparative anatomy study is being done to compare the design of their gills to that of tunas, another high-performance fish, though tunas are in the class of bony fishes, Osteichthyes, and sharks are cartilaginous being members of Class Chondrichthyes.  For this reason, the gills of available specimens are being collected.

Shortfin makos (and, incidentally, common thresher sharks which also might be seen on this trip) are among the very few warm-blooded species of shark.  Higher temperatures facilitate their higher energy usage as the fastest sharks in the ocean.  Makos achieve higher body temperatures, in part, because their “red muscle” tissue is located close to the spinal column and not, as in most other sharks, close to the skin.  This red muscle is responsible for maintaining prolonged periods of powerful movement.  This muscle works in tandem with the circulatory system to create a heat exchange system called countercurrent circulation. The internal location of the red muscle and the countercurrent circulation work to preserve heat and even warm the blood before it reaches the heart.  For these reasons, studies are being conducted on the red muscle versus white muscle are being sampled for later examination.

Because of the mako’s high performance, and the relation of that performance to the circulatory system, heart tissue is also being collected. The vertebrae of the makos is being collected, too, for the purposes of trying to determine the ages of the animals.  This was discussed some yesterday in the discussion of oxytetracycline injections.

Finally, a cutting from a fin is also being collected to later extract DNA.  Relatively little is known about the movement of makos (hence our tagging of them).  By examining the genetic relationship of makos sampled, researchers will be able to determine if makos off the California coast are related to makos in other parts of the Pacific, including the southern hemisphere.

Personal Log 

Aside from the critters at hand, there have been lots of other activity to feed our curiosities. We’ve been seeing whale spouts, probably fin or blue whales, and Risso dolphins. Ann Coleman, an aquarist with Monterey Bay Aquarium and another member of the science team, suggested we might even see some molas!  Molas are the largest bony fish in the world reaching 1500 pounds and a record of 14 feet in total length!  We can hope!

Thankfully, I’ve had zero issues with seasickness.  In fact, I’ve rather enjoyed being rocked to sleep at night. And, thankfully, the food has been plentiful and quite yummy!  That’s all for now…

Brenton