Category: NOAA Teacher at Sea

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Geoff Goodenow, May 17, 2004

NOAA Teacher at Sea
Geoff Goodenow
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004

Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 17, 2004

Time: 1600

Lat: 18 24 N
Long: 157 47 W
Sky: Stratus cloud layer shielded us from the sun until longline was in then it started to break up by 1030. Sun for awhile then clouded over again by midafternoon. Thinning by evening but still a good blanket on us.

Air temp: 27.3 C
Barometer: 1011.24
Wind: 35 degrees at 7 knots
Relative humidity: 54.5%
Sea temp: 26.8 C
Depth: 4489.2 m

Sea: 2-3 foot swells; no problems

Science and Technical Log

Yesterday after picking up the line we began a westward passage toward Swordfish Seamount. It was a long way off and there was no hope of getting there last night. The line was set along our course at 18 34 N and 156 47 W at no particular oceanographic feature that I am aware of. Perhaps that is why out haul today was none too exciting — a couple escolar, a snake mackeral and two blue sharks. Only one of the blues was brought on board. We will be at Swordfish to set tonight and look forward to a more interesting catch tomorrow.

I have covered each of the areas of research going on by the science teams aboard for this cruise. Today, my focus will be on sharks. We have caught 4 species so far and that has aroused my interest in these animals. I’ll provide some general info as well as some specifics for the species we have caught. For those of you interested in more, my information comes from two sources: Smiths’ Sea Fishes by Margaret Smith and Phillip Heemstra, and Diversity of Life by E.O. Wilson.

Sharks along with skates and rays are among 700-800 species in the subclass Elasmobranchii of the Class Chondrichthyes. Like all members of the class, their skeletons are entirely cartilaginous, but Elasmobranchs are distinguished by an upper jaw that is not fused to the skull and 5-7 pairs of gill slits.

There are about 350 species of sharks ranging in adult size from the 23 cm green lanternshark to whale sharks, the largest of all fishes, which reach 13 meters. Sharks lack a swim bladder, but produce large amounts of lipids which are stored as oils in the liver for buoyancy. The liver can account for up to 25% of the animal’s total weight. Sharks maintain osmotic (water) balance by maintaining a high concentration of urea (so high as to be deadly to most fishes) in their blood and tissues thereby reducing water loss to their salty environment.

All sharks we have caught (except the bigeye thresher, Order Lamniform) belong to the Order Carchariniform. This is the largest group of sharks; it includes about 200 species. These two orders are distinguished from one another in the following ways:

Carchariniforms: purse-like egg cases or live bearing; a movable nictitating membrane (eye covering).

Lamniforms: bear live young with uterine cannibalism (now there’s an interesting bit) evident in some; no movable nictitating membrane. There are also differences between the orders in the internal structure of their intestines — very interesting but I won’t go into description.

Specifics about each species of shark we have taken follow.

Blue sharks: the most fecund of all sharks; viviparous and bear 35-135 pups per litter; 50 cm at birth; attain 3.5 m; widespread in all oceans; favor water 12-16 C.

Oceanic white tip: in all oceans; away from continental shelves; viviparous bearing 6-8 pups usually; 60-65 cm at birth; up to 3 m; abundant in tropical seas.

Silky: widespread, prefer warm water; feeds inshore and in deep water; viviparous bearing 9-14 pups; 80-85 cm at birth; up to 3 m.

Bigeye thresher: widespread in warm ocean waters; ovoviviporous (provides embyo with no nourishment beyond the original yolk); 2 pups per litter; 100-130 cm at birth; attain 4.5 meters.

Personal Log

Well, I guess you can tell what I did today, and I might have a few more tidbits about sharks to add tomorrow. I am completing the log before the line set tonight so as to take in a movie afterwards. Don’t know what’s playing tonight, but it will be free and relaxing.

Tomorrow begins our last week at sea. Little time remains for you to file your questions with me. I’m looking too for suggestions for topics to try to address so if you have ideas, please suggest. I have asked for a tour of the engine room which is a possibility for Tuesday if tickets aren’t sold out. That might give me some interesting goodies to pass along.

Question:

We have seen fish that are rather uniformly dark in color and some that are brightly colored. What are some of the roles of coloration in fishes (as well as other animals)? Describe countershading and how it serves an animal like the blue shark.

Geoff

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Geoff Goodenow, May 16, 2004

NOAA Teacher at Sea
Geoff Goodenow
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004

Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 16, 2004

Time: 1615

Lat: 18 25 N
Long: 156 13 W
Sky: A dreary morning with gray stratus clouds all around and an occasional misting of precipitation. Much brighter sky by 1300 — enough to cast shadows, but remained mostly cloudy throughout the day. A pleasent evening with clearing skies.

Air temp: 25.7 C
Barometer: 1011.61
Wind: 352 degrees at 13 knots
Relative humidity: 71.5%
Sea temp: 26.4 C
Depth: 5012.1 m
Sea: 2-3 foot swells

Scientific and Technical Log

Longline retrieval started on a bad note this morning as the line went under the ship. It caused only a short delay as maneuvers were quickly and successfully made to keep it out of the propellers. We brought up an escolar, 2 snake mackeral, and a broadbill swordfish head. A large, angry silky shark came in also. The shark was released after being tagged and “kindly” relinquishing a remora. And finally, a new species for the record, a lancetfish (Alepisaurus ferox). These guys look much like the snake mackeral, a long thin body up to 200cm, nearly cylindrical with a tall uneven dorsal fin (sail)standing perhaps 5 body widths high over nearly 2/3 of its back. The snake mackeral’s dorsal fin does not rise nearly so much. The lancet’s skin was very smooth, scaleless in fact, iridescent and rather pale. They have narrow snout with long sharp teeth.

For those interested in the studies of pelagic fishes, the Pelagic Fisheries Research Program (PFRP) publishes a newsletter which can be viewed online (I think) at http://wwwsoest.hawaii.edu/PFRP . For more on the eye work being done by Kerstin and others see Vol. 6 Number 3 (July-September 2001).

Other studies aboard the SETTE:

Melissa is a master’s program student at Virginia Institute of Marine Sciences (VIMS). She did her undergraduate study at UC San Diego. She has been collecting remoras, larvae from our plankton tows and stomach contents from some fishes, and fin clips from sharks. Here’s what it’s all about:

The remoras are being collected as a favor for her labmate’s work at VIMS. That person is looking at the phylogenetics of remoras and also that of their hosts which include sharks, billfishes, and the occasional baitfish or float. She is also collecting fin clippings from sharks of the genus Carcharhinus (e.g. oceanic white tips, silky sharks) for another labmate working on the sandbar sharks (also in the Carcharhinus genus) off of Virginia, looking at natal homing patterns.

From the plankton tows, Melissa is interested in larvae of the fish family Scombridae which incldes tunas, wahoo, bonitos, and mackeral. Can we find ways to identify them based on their genetics? Samples from all will be sequenced using their mitochondrial DNA in an attempt to find unique interspecific (between species) genetic markers. The value of this is that it would allow easier identification of larval types than does morphological identification. We might more readily then identify where and when particular species spawn and thereby attain a better understanding of their life histories. Are the genetics of a species uniform throughout the range of the fish? If there are significant genetic differences in populations then perhaps it is wise to manage fisheries of that species by area as opposed to globally (one size fits all approach) so as to preserve gene pool diversity. Answers to these questions could lead to management practices that better protect these resources.

This work also has applications in forensic studies. Fish that have been taken illegally and already filleted can be identified by genetic markers enabling better enforcement of regulations. Also, morphological identification of degraded tissue, as in stomach contents where enzymes have done their deed, is impossible.  Stomach contents collected here will be screened using genetic markers for the tuna larvae to see if the larvae are part of that particular fish’s diet.  Applications from this work could potentially aid studies of trophic levels and predator/prey relationships.

Goodenow 5-16-04 shark on cradle
Shark being lifted aboard

Personal Log

Suffered my first injury in shark wrestling today with a slight abrasion to left knee — not enough to scare me away from the next match. Nothing too news worthy to report about the day. It was a rather slow day. Not much sun, humidity was above the norm — a bit uncomfortable outside. Continued reading Wilson’s book, did wash and stewards offered a linen change today which I took advantage of.

There was a moment of excitement this afternoon when a marlin took off with a troll line. It was out of control and our two champion fisherman couldn’t handle it. Gears were stripped in the reel which actually smoked from the heat generated as line spinned off. That rod is out of action for the duration; the fish won that round.

This evening our electronics technician, John, gave me a pictorial introduction to other research cruises of the SETTE which I will share with you another time. And, relieved of longline duties tonight, I spoke with Mike and science in general and some specific regarding his work in fisheries research.

To all of my ’02-’03 Advanced Biology students, I am sorry to report that I was not able to make use of my Secchi disk nor did I even see one on the ship.

Question:

What does the term upwelling mean? Identify several general locations in the oceans where upwelling occurs. What is the biological impact of upwelling in those areas?

Geoff

Posted on

Geoff Goodenow, May 15, 2004

NOAA Teacher at Sea
Geoff Goodenow
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004

Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 15, 2004

Time: 1550

Lat: 18 52 N
Long: 155 47 W
Sky: Bright and sunny over us but the island has a layer of stratus obscuring views to top
Air temp: 26.3 C
Barometer: 1012.72
Wind: 202 degrees at 12 knots
Relative humidity: 62.4
Sea temp: 26.2 C
Depth: 2015.4 m

Sea: Rolling along with 2-3 foot swells; no big deal.

Scientific and Technical Log

Scientific name for the pomfret we caught yesterday is Brama brama and for the silky shark (caught a week or so ago) it is Carcharhinus falciformis.

Today as we trolled just off the Hawaii shoreline as we steamed south to our longline set position. Mike and Chris teamed up again to land a shortbilled spearfish (Tetraturus angustirostris) 161 cm and 17 kg, silvery body with a deep blue dorsal fin — beautiful fish. This one was kept for eye studies and other tissue samples. We pulled a nearly intact fish about 20 cm long from its stomach. The 2 man team of Chris and Mike is working smoothly and efficiently; no fish has a chance against them now.

We will set the longline tonight southeast of the southern tip of Hawaii at Apuupuu Seamount, 929 m below. (18 31N, 155.24 W). Following the set we will be doing a plankton tow.

Vision (one more time):

Another aspect of the vision studies is trying to assess the animal’s speed of vision. Electroretinography measures the response of an eye to light pulses from a flickering source. So called flicker fusion (FF) is reached when the eye loses its ability to perceive individual pulses of light. A relatively high FF value is characteristic of shallow living species compared to deeper dwellers. In the dim light the speed of light gathering is slowed similar to the need to slow a camera’s shutter speed to gather sufficient light.

In concluding this abbreviated look at the vision studies, I’ll try to draw some of the pieces together. Pop up tags show where these animals spend their time in terms of depth, light and temperature realms. We can tell how sensitive an eye is to light and how fast it works. As you will recall, some of these fishes deep dwelling fishes have heat a exchange system located in the eye which keep it warm. It has been shown that speed of vision is affected by temperature change — a warm (above ambient) eye functions more effectively. Much more goes on, but perhaps you get a sense of how different areas of study contribute to a better picture of this function in these pelagic fishes.

To other (non-vision) studies tomorrow.

Personal Log

We steamed toward Kona through the night so that we could ferry Steven to shore and flights to other places. It was great to have met him; I’m sorry he had to jump ship. I got up at 5:30 to experience sunrise (around 6 o’clock). I thought it would be nice to see it rise over the island, but didn’t count on the clouds hanging over the mountains to obscure anything that might have been spectacular; it wasn’t even good from our perspective. But it was nice to see a color that I haven’t seen (except as a flash) in over a week — green. We have been wrapped in a beautiful blue and white world (which I am sure would excite fans of the Penn State Nittany Lions and the Mifflinburg HS Wildcats), but I tend to favor green fields and forests in the mix.

Unfortunately, we didn’t get to touch the green or for that matter the briny deep as snorkeling was denied us. So it was a day of leisure on board. I spent time reading (Diversity of Life), making some journal entries and enjoying the sight of land — perhaps the last for another 9 days (not complaining). I tried to ignore the typical signatures of human presence at Kona: autos, the Big K-Mart and Lowes perched to give exiting customers a grand view across the sea, a cruise ship at anchor, shore front hotels and homes dotting the mountainside. I directed my focus on the crashing surf, blankets of exposed black lava rock interrupting the predominant green, and shear black cliffs dropping to the sea — the natural stuff. It got better the further south we moved along the coast.

Dan guided Kylie and me through filleting of the spearfish this afternoon. Between the three of us (and the catch team, of course) we secured a good bit of food for the crew. This evening I split spool duty with Kerstin then took a chair from which to watch the rest of the set, read and talk with super fisherman Chris.

It’s a great night back in the world of blue and white.

Question:

Can you find the point on the sea where you would be most distant in any direction from land?

Posted on

Geoff Goodenow, May 14, 2004

NOAA Teacher at Sea
Geoff Goodenow
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004

Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 14, 2004

Time: 1600

Lat: 18 40 N
Long: 158 14 W
Sky: Sunnny with widely scattered cumulus
Air temp: 26.4 C
Barometer: 1011.26
Wind: 172 degrees at 12 knots
Relative humidity: 61.4%
Sea temp: 26.4 C
Depth: 888.5 m

Sea: A few white caps out there; swells in 1-3 foot range — easy going today.

Science and Technology Log

A fairly exciting morning on the longline. Several escolar, a barracuda, and a pomfret (a laterally flattened fish about 30cm long but only 2-3 cm in width with a fine set of sharp teeth). Samples taken from all. We also had a blue shark from which samples were taken and an oceanic white tip shark which was tagged and released. I got to wrestle both. Picked up a few remoras from the sharks. We think we have at least two species of remoras.

This afternoon we passed over Cross Seamount and traversed it several times as we trolled but to no avail. There will be no longline set tonight since we have a date in Kona to drop off one of the current scientific party.

I want to fill in with more of the vision story this evening if I can stay coherent long enough to convey it sensibly. I will touch on the work of Steven, Kerstin, and Rickard.

I have been collecting samples of fish lenses. They vary in size, as you would expect, among different sized fishes. What makes the lenses different from those of most vertebrates is that they are spherical rather than oval in cross section. The cornea of fish is also optically non-functional. Since it has the same refractive index as water, focusing is done by moving the lens back and forth in the eye rather than by changing the shape of the lens as our eye muscles do.

Steven uses laser light to determine the focal point for different colors of light. He suspends lenses in a fluid medium then turns on a laser beam that makes two vertical passes through the diameter of the lens. You can watch light’s path change as the beam migrates. Computer analysis then determines focal point.

Kerstin and Rickard must have live cells from the retina for their studies. Among other things, they are looking at the sensitivity of these cells to different light intensities. Live retina cells convert light to electrical signals which travel via the optical nerve to the brain to produce an image. By attaching electrodes to tissue samples about 1 cm square in size and subjecting the cells to different intensities of light electrical responses of different strengths can be detected and measured. They appear as a wave pattern on a screen. As light intensity is increased, the amplitude of the wave pattern increases. So a flat line (no response) becomes one with small amplitude waves which grow as light intensity increases to a point where more light produces no greater effect.

Lets compare two species, mahi mahi, which stay nearer well lit surface and bigeye tuna which like deeper environs. Which eye would you expect to be more light sensitive? The bigeye. Their cells are stimulated by much lower intensities of light than the mahi’s. They (bigeye) have to be able to detect their prey under minimal light conditions and need the more sensitive eye to do that. Big eyes, big pupils (fish pupil size is fixed) and a “super” sensitive set of retinal cells are adaptations of these fish to their deep environment.

I’ve had enough (as I suppose you have too). I will wrap up the vision story tomorrow or Sunday.

Personal Log

We are headed for Kona. Although we probably will not get any shore time, it has been suggested that there might be an excursion to a place where we can swim/snorkel for awhile. I am hoping very much this it true as are others. A plunge into this element (I guess I should say compound) that we have bobbed around on top of for the past 13 days would be a pleasant change in the routine and scenery.

Reading E.O. Wilson’s The Diversity of Life.

I would like to thank, Ron, a fellow teacher from Michigan who I have never met, for writing a note to tell me that he has been enjoying the logs and also to pose a question. Much appreciated!

Questions:

Sunrise here today is at 6AM and the great yellow ball sets here at 7PM. What time is it rising and setting in your area at this time of year? Find out sunrise and sunset times for the solstices for Honolulu and your area. From that determine A) how much longer the sun is above the horizon for each place in summer vs winter B) which place, Honolulu or your home has more sun time at each solstice? If you find that there are differences explain why they exist.

Geoff

Posted on

Geoff Goodenow, May 11, 2004

NOAA Teacher at Sea
Geoff Goodenow
Onboard NOAA Ship Oscar Elton Sette
May 2 – 25, 2004

Mission: Swordfish Assessment Survey
Geographical Area: Hawaiian Islands
Date: May 11, 2004

Time: 1600

Lat: 18 49 N
Long: 158 03 W
Sky: A gray overcast morning with a couple of showers. Brightened through the late morning and stayed mostly(thin)overcast but enough sun to cast shadows and feel pretty intense. 90% cloud cover through most of daylight hours. Tonight the sky is star-filled — beautiful.

Air temp: 26.3 C
Barometer: 1011.9
Wind: 100 degrees at 8 knots
Relative humidity: 66.9%
Sea temp: 26.7 C
Depth: 3333 m

Sea: A bit of chop especially this morning when wind seemed stronger. There were a couple of splashes onto the deck as we brought in the line this morning. Still some whitecaps this afternoon; well settled this evening.

Salinity: 34.4 (I thought some might be wondering; it has been consistent throughout.)

Scientific and Technical Log

This morning we brought in several escolar (none scoring better than 4 as they belly flopped to the surface), a yellowfin tuna which was tagged and released, and three blue sharks (one was kept and two were returned after blood samples and a couple remoras were secured). Shark wrestling is getting to be routine. Since then we have been steaming northeast beyond Cross Seamount. At 2000 we are at Lat 19 10N and Long 157 45 W as we begin the set.

On minor correction: sharks and other big fish brought on board are hoisted by human muscle using a block and tackle (not a mechanical winch as stated previously)

Kerstin Fritsches from the University of Queensland in Brisbane, Australia is working on vision studies of the fish. Her husband, Steven Evill (often affectionately referred to as Dr. Evil) assists as do three graduate students, Rickard and Eva from Sweden, and Kylie, also from Brisbane. It is for these studies that the eyes are taken from the animals. I will attempt to explain some practical applications of their studies and give you a sense of the kinds of work being done on board. I will do this in several editions of the log — not all at once. So to start —

Fishes, depending on species may use a variety of senses to know their environment. Scent, for example, may allow them to home in on prey.   While research goes on by others to analyze other sensory structures and abilities, Kerstin’s work is about vision. The attempt is being made to find out just what these different fishes are able to see. Do they see differently and, if so, how so? The practical application for longline fisheries, a very indiscriminate practice, is to eliminate by-catch. This can help protect endangered species and make longlining more cost and time efficient by finding ways to attract only economically valued species.

The water column is visually quite a varied environment. Longer wavelengths of red light are essentially filtered out and gone within the first 50 meters below the surface while shorter wavelengths in the blue range penetrate the depths. But imagine hanging out, living, and hunting at 600 meters as some of these fish do, in daytime light levels the equivalent of a starry night at the surface. Some such as swordfish and bigeye tuna come toward the surface at night keeping their exposure to light levels constant. Imagine your life spent in light levels no greater than that of a starlit night. What adaptations do these animals have to accommodate such a lifestyle? What are different parts of the visual apparatus doing in these animals? In order to help uncover answers to these and other questions, three kinds of projects are going on here.

When a live fish of desired species comes aboard, it is first killed then its eyes are taken. Kerstin and Rickard must have living tissue from the retina for their studies. They have about 20 minutes in which to get the tissue they need into a special oxygen-rich solution in which the tissues will be good for 6-8 hours. Steven works with lenses which do tend to cloud over time, but he is able to easily accomplish his work before that happens. For Eva and Kylie there is no rush as their samples, retinas and eyes with only lenses removed, are destined to be preserved for later study at home. I’ll pick up from here tomorrow with details about specific aspects of the work on vision. In preparation you might look up what the retina and lens of the eye do.

Personal Log

I observed our hitchhiking birds in a new feeding maneuver this morning. A bunch of flying fish took to the air and were happily gliding along. Our friends took after them and approaching from the rear snatched them out of the air.

Filling in the non-fishing time gaps: Last night I interviewed Eva about her part of the vision studies and this afternoon Rickard took me through his experiments. At home in Sweden he does vision studies on insects, moths and butterflies in particular. I am also reading Adam’s Navel which I can recommend to those with an interest in human biology written in an interesting non-technical and often humorous style. And it is often nice to find some shade, a comfortable deck chair and with a beverage in hand stare across that wide, blue expanse of water.

The days pass quickly.

Goodenow 5-11-04 sunset
Sunset from NOAA Ship OSCAR ELTON SETTE.

Questions:

I am happy to report that we are eating quite well on our voyage, but that was not the case for early voyagers across the seas. At times they might have had plenty to fill their stomachs, but at the same time lack a balanced diet. Because of this, one condition the mariners suffered was scurvy. What are the symptoms/problems associated with that condition? What can be done to prevent it? See if you can find out when and how the solution to the problem was discovered.

Geoff