Kristin Hennessy-McDonald: Nurse Sharks, Tiger Sharks, and Sandbars, Oh My, September 27, 2018

NOAA Teacher at Sea

Kristin Hennessy-McDonald

Aboard NOAA Ship Oregon II

September 15 – 30, 2018

 

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 27, 2018

 

Weather Data from the Bridge

Latitude: 2840.20N

Longitude: 8439.79W

Sea Wave Height: 0m

Wind Speed: 2.2 knots

Wind Direction: 39.04 degrees

Visibility: 10 nautical miles

Air Temperature: 30.045

Sky: 75% cloud cover

 

Science and Technology Log

We have moved from the coast of Texas, past Louisiana, Mississippi, and Alabama, to the coast of Florida.  When watching the video from the CTD, we have seen the sea floors go from mostly mud to sand.  The water has decreased in turbidity, and the growth on the sea floor has increased.  The make-up of our catches has changed too.  We moved outside of the productive waters associated with the Mississippi River discharge, so our catch rates have decreased significantly.

Yesterday, we had a fun day of catching sharks I had never seen.  Our first catch of the day brought up a juvenile Tiger shark (Galeocerdo cuvier).  I was excited to be able to see this shark, which is listed as near threatened by the International Union for Conservation of Nature.  On our later catch, we brought up three sharks large enough to require the cradle.  First, we brought up a Sandbar shark (Carcharhinus plumbeus).  Then, we were lucky enough to bring up a Nurse Shark (Ginglymostoma cirratum).  The mouth of the nurse shark has barbles, which it uses to feed from the sea floor.  Our final shark of the evening was a much more developed Tiger Shark.  I was lucky enough to help with the tagging of the animal.

juvenile Tiger Shark

Kristin Hennessy-McDonald with a juvenile Tiger Shark

Nurse Shark

Closeup of a Nurse Shark

Nurse Shark release

Nurse Shark release

Last night, we set a line at the end of day shift, and night shift brought it in.  A few of the day shift science team members decided to stay up and watch some of the haul back, and were rewarded with seeing them bring in, not one, but two Silky sharks (Carcharhinus falciformis), back to back.  From the upper deck of the ship, so that I was not in their way, I was able to observe the night shift work together to bring up these two large animals.

Silky Shark

Night Shift retrieving a Silky Shark

The night shift has gotten some pretty amazing catches, and they have enjoyed sharing them with us at shift change.  The two shifts spend about half an hour together around noon and midnight sharing stories of the time when the other shift was asleep.  The other day, the night shift caught Gulper Sharks (Centrophorus uyato) and Tile Fish (Lopholatilus chamaeleonticeps).  These are two species we have not seen on the day shift, so it was fun to look at their pictures and hear the stories of how they caught these fish.

Gulper Shark

Gulper Shark Photo Credit: Gregg Lawrence

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Tilefish Photo Credit: Gregg Lawrence

 

Personal Log

When we have a long run between stations, once I have gotten done sending emails and grading student work, we will spend some time watching movies in the lounge.  The ship has a large collection of movies, both classic and recent.  Watching movies keeps us awake during the late night runs, when we have to stay up until midnight to set a line.

The day shift has started to ask one another riddles as we are baiting and setting lines.  It’s a fun way to bond as we are doing our work.  One of my favorites have been: “1=3, 2=3, 3=5, 4=4, 5=4, 6=3, 7=5, 8=5, 9=4, 10=3.  What’s the code?”

Did You Know?

Sharks don’t have the same type of skin that we do.  Sharks have dermal denticles, which are tiny scales, similar to teeth, which are covered with enamel.

Quote of the Day

Teach all men to fish, but first teach all men to be fair. Take less, give more. Give more of yourself, take less from the world. Nobody owes you anything, you owe the world everything.

~Suzy Kassem

Question of the Day

I have a lot of teeth but I’m not a cog
I scare a lot of people but I’m not a spider
I have a fin but I’m not a boat
I’m found in the ocean but I’m not a buoy
I sometimes have a hammerhead but I don’t hit nails

What am I?

Stephen Kade: The Shark Cradle and Data Collection, August 8, 2018

NOAA Teacher at Sea

Stephen Kade

Aboard NOAA Ship Oregon II

July 23 – August 10, 2018

 

Mission: Long Line Shark/ Red Snapper survey Leg 1

Geographic Area: 31 41 010 N, 80 06 062 W, 30 nautical miles NE of Savannah, North Carolina

Date: August 8, 2018

 

Weather Data from Bridge:

Wind speed 11 knots,
Air Temp: 30c,
Visibility 10 nautical miles,
Wave height 3 ft.

Science and Technology Log

Normally you wouldn’t hear the words shark and cradle in the same sentence, but in our case, the cradle is one of the most important pieces of equipment we use each day. Our mission on the Oregon II is to survey sharks to provide data for further study by NOAA scientists. We use the long line fishing method where 100 hooks are put out on a mile long line for about an hour, and then slowly hauled up by a large mechanical reel. If a shark is generally three feet and weighs 30lbs or less, it is handled by hand to carefully unhook, measure and throw back. If the shark is much larger and cannot be managed safely by hand, it is then held on the line by the ships rail until it can be lifted on deck by the cradle to be quickly measured, tagged, and put back into the ocean.

The shark cradle

The shark cradle

The shark cradle is 10 ft. long, with a bed width of roughly 4 feet. It is made from thick aluminum tubing and strong synthetic netting to provide the bed for the shark to lie on. It is lifted from the ship’s deck by a large crane and lowered over the ships rail into the ocean. The shark is still on the line and is guided by a skilled fisherman into the cradle. The crane operator slowly lifts the cradle out of the water, up to the rail, so work can begin.

A team of 3 highly skilled fishermen quickly begin to safely secure the shark to protect it, and the team of scientists collecting data. They secure the shark at 3 points, the head, body and tail. Then the scientists come in to take 3 measurements of the shark. The precaudal measurement is from the tip of nose to the start of the tail. The fork measurement is from the tip of the nose to the fork of the tail (the place where the top and bottom of the tail meet). Finally there is a total length taken from the tip of the nose to the furthest tip of the tail.

When all measurements are complete, a tag is then placed at the base of the first dorsal (top) fin. First a small incision is made, and then the tagger pushes the tag just below the skin. The tag contains a tracking number and total length to be taken by the person who finds the shark next, and a phone number to call NOAA, so the data can recorded and compared to the previous time data is recorded. The yellow swivel tags, used for smaller sharks, are identical to ones used in sheep ears in the farming industry, and are placed on the front of the dorsal fin. The measurements and tag number are collected on the data sheet for each station. The data is input to a computer and uploaded to the NOAA shark database so populations and numbers can be assessed at any time by NOAA and state Departments of Natural Resources.

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A skilled fisherman removes the hook so the shark can be released.

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The longline is mile long and carries up to 100 hooks.

The shark is then unhooked safely by a skilled fisherman while the other two are keeping the shark still to protect both the shark and the fishermen from injury. The cradle is then slowly lowered by crane back into the ocean where the shark can easily glide back into its environment unharmed. The cradle is then raised back on deck by the crane operator, and guided by the two fishermen. All crew on deck must wear hardhats during this operation as safety for all is one of NOAA’s top priorities. This process is usually completed within 2 minutes, or the time it took you to read this post. It can happen many times during a station, as there are 100 hooks on the one mile line.

 

 

Personal Log

It is amazing for me to see and participate in the long line fishing process. I find it similar to watching medical television shows like “ER” where you see a highly skilled team of individually talented members working together quickly and efficiently to perform an operation. It can be highly stressful if the shark is not cooperating, or the conditions aren’t ideal, but each member always keeps their cool under this intense work. It’s also amazing to see the wealth of knowledge each person has so when an issue arises, someone always knows the answer to the problem, or the right tool to use to fix the situation, as they’ve done it before.

Animals Seen Today: Sandbar shark, Tiger shark, Sharpnose Shark, Sea Robin, Toadfish, Flying Fish

Kate Schafer: The Importance of Science, October 4, 2017

NOAA Teacher at Sea

Kate Schafer

Aboard NOAA Ship Oregon II

September 17 – 30, 2017

 

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: October 4, 2017

 

Weather Data from the San Francisco Bay area:

Latitude: 37o 38.4’ N
Longitude: 122o 08.5’ W

Visibility 16 km

Winds 5-10 mph

San Francisco Bay Water Temperature 16 oCelsius

Air Temperature 17 o Celsius

 

Science and Technology Log:

Well, I’m back on dry land, with lots of great memories of sharks, big and small, and all the interesting people who I spent two weeks with on the Oregon II.  And let’s not forget the red snappers either.

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The largest shark we caught: 10 foot tiger shark

 

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Cuban dogfish: The smallest species we caught

On our last day, we fished at a couple of sites right off the coast of Alabama and caught lots of sharks, plus a new species of grouper for the trip.  The scamp grouper (Mycteroperca phenax) is apparently not frequently found on the longlines along the coast of Texas but becomes more common along the coasts of Mississippi and Alabama and up the Eastern Atlantic coast as well.

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Tail of a Scamp Grouper

The groupers are mostly protogynous, meaning that when they become sexually mature, they are always females.  Only later in life, when they have grown bigger (and have the right environmental influences), do they transition to males.  This species can live for more than 30 years, but that’s actually relatively short for a lot of the grouper species, some of which can live to 60 years or more. Scamp grouper come together in groups to reproduce, so this makes them vulnerable to overfishing.  The management councils take this into consideration when making a management plan and will close off areas known to be spawning grounds during the reproductive season.  These are also great areas to target as Marine Protected Areas.

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Scamp Grouper being measured

All of this knowledge about the scamp grouper (and other species we encountered on this survey) was gained through careful scientific research.  As mentioned before, the long line survey was started in 1995 and has been conducted using the same methods every year since then.  These data are used by fisheries managers to set catch limits and detect changes that might indicate problems for the species living in these areas.  In other words, the science forms the basis for decision making and planning.

This is true for the various surveys that NOAA conducts in the Gulf each year.  The Groundfish Survey, for example, provides vital information about the extent of the Dead Zone off the coast of Louisiana, by measuring dissolved oxygen levels on the sea floor as part of the survey.  This data tells us that we need to continue to work on controlling nutrient inputs into the Mississippi River from agriculture lands and cities that span much of the eastern United States.  Scientific research also tells us that we need to be planning for and mitigating the effects of the looming problem of climate change.

Climate change will certainly bring about significant change to the Gulf.  As ocean temperatures rise, water becomes less dense and therefore takes up more space.  Along with continued melting of land-supported ice in the polar regions, this is contributing to a cumulative increase in sea level of 3.2 mm per year (https://oceanservice.noaa.gov/facts/sealevel.html).  In the Gulf, this increase will particularly impact estuarine ecosystems that are rich nurseries for many fish species and are extremely productive habitats.

One of the predictions of many climate models is that increased global temperatures are likely to bring about more frequent and more intense hurricanes.  This 2017 hurricane season is a stark reminder of the devastating impacts that hurricanes can have, even when we have the scientific tools to predict approximately where and when the storm will make landfall.

Finally, the increase in global temperatures will make the regions surrounding the Gulf less pleasant places for people to live.  The summers are already very hot and humid, and a degree or two hotter will make a lot of difference in the livability of the region.

We know all of this through careful scientific research, and there is a consensus amongst scientists that this is happening.  To prepare for the effects of climate change and to know how to best minimize those effects, we must continue to collect data and do science.  After all, what is the point of scientific research if we don’t use the results to make better choices and to address the problems that are facing us?

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At the end of my time on the Oregon II

Personal Log:  I am so grateful for the opportunity to go on this research survey and for the Teacher at Sea program as a whole.  I strongly encourage any teacher thinking of applying to the program to do so.  Thanks to NOAA and everyone at the TAS office for all your help and support.

 

 

 

 

 

 

 

And We’re Fishing…

NOAA Teacher at Sea

Kate Schafer

Aboard NOAA Ship Oregon II

September 17 – 30, 2017

 

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 21, 2017

 

Weather Data from the Bridge:

Latitude: 27o 15.5’ N

Longitude: 97o 01.3’ W

Haze

Visibility 6 nautical miles

Wind SE 15 knots

Sea wave height 3-4 feet

Sea Temperature: 29.6o Celsius

Note: Just a month ago Hurricane Harvey was bringing 20 foot seas to this area, but today we’re enjoying the 3-4 foot swell.

Science and Technology Log:

Well, we’ve gotten to the fishing grounds, and we’ve gone from waiting to very busy!  We put out the first lines starting at around 8 pm on Tuesday evening.  The process involves first baiting 100 hooks with Atlantic mackerel.  When it’s time for the line to be deployed, first there is a tall buoy with a light and radar beacon (called a high flyer) on it that gets set into the water, attached to the monofilament fishing line.  Then there’s a weight, so the line sinks to the bottom, a series of 50 baited hooks then get clipped onto the line as the monofilament is being fed out.

Those 50 hooks are referred to as a “skate”.  This confused me last night when I was logging our progress on the computer.  I kept thinking that there was going to be some kind of flat, triangular shaped object clipped on to help the line move through the water…not really sure what I was imagining.  Anyway, Lisa Jones, the field party chief and fisheries biologist extraordinaire, has so kindly humored all my questions and explained that skate is just a term for some set unit of baited hooks.  In this case, the unit is 50, and we’ll be deploying two skates each time.

After the first skate comes another weight, the second skate, another weight and then the last high flyer.  Then the line is set loose and we wait.  It’s easy to locate the line again, even at night, because of the radar beacons on the high flyers.

Why are we collecting this data?

As mentioned in my previous post, one of the tasks of NOAA, especially the National Marine Fisheries Service Line Office, is to collect data that will help with effective fisheries management and assist with setting things like catch quotas and so forth.  A catch quota refers to the amount of a particular species that can be harvested in a particular year.  Fisheries management is incredibly complicated, but the basic idea is that you don’t want to use up the resource faster than it is replenishing itself.  In order to know if you are succeeding in this regard, you must go out and take a look at how things are going.  Therefore, the Oregon II goes out each year in the fall and samples roughly 200 sites over about eight weeks.  The precise locations of the sampling sites change each year but are spread out along the SE Atlantic Coast and throughout the U.S. waters in the Gulf of Mexico.

We’ve put out three long lines so far.  Last night, we caught a single fish, but it was a really cool one.  It’s called the Golden Tilefish but has an even better species name: Lopholatilus chamealeonticeps.  As Lisa was explaining that they dig burrows in the sea floor, I realized that I had seen their cousins while snorkeling around coral reefs but would never have made the connection that they were related. This guy was big!

 

Tilefishp3

Golden tilefish (Lopholatilus chamealeonticeps) caught in first longline of the trip

This afternoon, things got really hectic.  Of our 100 hooks, 67 had a fish on it, and 60 of those were sharks.  As we were pulling in the last bit of line, we pull on a shark that was missing its back half!  Another had a bite taken out of it.  And then on hook number 100, was a bull shark.  This shark had been snacking along the line and got caught in the process.

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Bull shark caught on the last hook of a very productive bout of fishing (Photo courtesy of Lisa Jones, NOAA)

And I haven’t even mentioned the red snappers.  I will save them for another post, but they are absolutely beautiful creatures.

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Red snapper being measured

 

Personal Log:

I definitely continue to feel out of my element at times, especially as we were pulling in all these hooks with sharks on them, and I could barely keep up with my little job of tracking when a fish came on the boat.  All the sharks started running together in my mind, and it was definitely a bit stressful.  Overall, I feel like I’ve adjusted to the cadence of the boat rocking and have been sleeping a lot more soundly.  I continue to marvel at how amazing it is that we’re relatively close to shore but, except for a few songbirds desperate for a rest, there is no evidence of land that my untrained eyes can detect.  Lastly, I’ve realized that a 12-hour sampling shift is long.  I have a lot of respect for the scientists and crew that do this for months on end each year with just a few days break every now and then. Well, it time to pull in another line.  Next time, we’ll talk snapper.

 

Susan Brown: Weather or Not, September 9, 2017

NOAA Teacher at Sea

Susan Brown

NOAA Ship Oregon II

September 3 – 15, 2017

 

Mission: Snapper/Longline Shark Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 7, 2017

Weather Data from the Bridge

Latitude: 2095.92N
Longitude: 08825.06W
Sea wave height: 1.2 m
Wind Speed: 20.3kt
Wind Direction: 50 degrees
Visibility: (how far you can see)
Air Temperature: 025.6 degrees Celsius

Barometric Pressure: 1018.36 mb
Sky: cloudy

Science and Technology Log

The weather has been a big topic of conversation on this survey and for good reason. The original plan was to fish off the coast of Texas from Brownsville to Galveston. Due to Hurricane Harvey and possible debris in those waters, the survey changed course to sample off the coast of Florida. As we motored east, Irma was building up to a category 5 hurricane.

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Captain Dave

 

Captain Dave has been keeping a keen eye on the weather and after a few days of fishing off the coast of Florida, we headed back toward Pascagoula, Mississippi to pick up a crew member and let another off to tend to his family in Florida which is in the current path of Irma. We have been looking at the various computer modeling showing where Irma will land and this determining our path. Fortunately, a cold front to the west of us is pushing Irma east which will allows to stay out instead of docking and ending the survey early. This cold front is unusual for this time of year according to the Captain. Earlier models showed Hurricane Irma hitting the west side of Florida into the Gulf of Mexico where we are which would end our survey. Now, with the updated weather, we may get to stay out as planned but staying close to Mississippi and then heading West to work off the coast of Texas and Louisiana.

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Daily updates and rerouting due to weather

This ship is part of the Ship of Opportunity Program (SOOP). This program enlists ships to collect weather data that is sent to the National Weather Service (a line office of NOAA) every hour. This is the data that supplies information to weather forecasters! Information that is gathered includes wind speed and direction, barometer reading, trend in pressure over the past few hours, as well as wind, wave and swell information. Have you every noticed on TV that the weather reports have a notification that states the data is coming from NOAA? Weather forecasters get weather information from ships out in the ocean like the one I am on.

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another beautiful sunset from the top deck

This morning I headed up to the bridge to chat with Captain Dave. Here are some of the questions I asked.

Q: How long have you been a captain?

CD: 9 years

Q: What got you interested in this type of work?

CD:I grew up in Mississippi where you hunt and fish so when I got out of high school I always wanted to work on the water due to my upbringing. We were always taking out the boat to hunt or fish growing up. It’s in my blood.

Q: What is your schooling? What advice would you give someone that is interested in this as a career?

CD: I graduated high school in 1980 and made my living on the water commercial fishing and working on the oil rigs until January 4, 1993. I started as a deck hand and worked my way up to Commanding Officer (CO). I’ve been on the Oregon II 25 years. The hardest thing was taking the test to be a Master.

Captain Dave is a civilian Master which is rare – there are only two in the NOAA fleet. Most NOAA ships are run by NOAA Corps Officers. 

Q: What is the biggest storm you have seen?

CD: East of Miami, Florida in the gulf stream we were seeing 12-15 foot seas. The engine room calls the bridge regarding a busted intake valve. The boat was sinking. The engineers were in knee deep water and were able to find the broken valve and stop the flooding. In another 7 minutes the generator would have been under water and we would have lost power and would be forced to abandon ship in 12-15 foot waves.

Q: Is this weather unusual for this area this time of year?

CD: We never get a NE wind bringing in cooler weather which is probably what is turning Hurricane Irma. Normally it’s blazing hot here with southwest winds at 10 miles. This cold front is the reason we are not going in.

Check out this cool animated site for wind patterns. You can see how the hurricanes impact the flow of air.

https://www.windy.com/?47.680,-122.121,5

Personal Log

So far the seas have been calm and I keep expecting things to pick up because of all the weather happening around us. Sleeping pretty good with slow rocking of the ship and we will see how I do with some bigger swells. The crew has been super helpful in doling out advice from how keep from getting seasick ranging from eating, drinking and even how best to walk! I’m listening to all this advice and so far so good. I do wonder how much of Hurricane Irma we will feel now that we are heading west a few hundred miles.

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The one that got away!

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baiting the line with Mackerel

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Spinner shark

We have caught a few sharks and I am excited to catch some more. Other critters we have caught were a bunch of eels and a suckerfish. On yesterday’s shift I learned how to tag one of the big sandbar sharks. She was about 6’ long. The night crew caught a 10’ tiger shark! Maybe we will get lucky on today’s shift as I would love to see more sharks and handle some of the smaller ones.

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suckerfish

Update: Last night our shift brought in 16 sharpnose sharks so things were busy. These sharks don’t get much bigger than 3 ½ feet. All of the ones we pulled in last night were female. The oceans have gotten a bit rougher with swells 4-5 feet! I have gained a new appreciation for all the rails available along the corridors of the ship and have learned to make sure my door is clicked shut as well as all the cabinets and drawers. Nothing like waking up to drawers slamming open and shut in the middle of the night!

Did You Know?

A Captain of the ship can be ranked as a Captain or a Commander within the NOAA Corps but a civilian does not hold a commissioned rank because they are not in the NOAA Corps and is called a Captain since he holds a Master license gained by taking extensive coursework and an intensive exam through the United States Coast Guard.

Question of the day:

What is the difference between a category 5 hurricane and lesser hurricanes? (hint: check out the link below)

http://abcnews.go.com/US/hurricanes-form-explained-abc-news-chief-meteorologist-ginger/story?id=49650211

 

 

 

 

 

Susan Brown: Probing for Parasites, September 5, 2017

 NOAA Teacher at Sea

Susan Brown

Aboard NOAA Ship Oregon II

September 3 – 15, 2017

 

Mission: Snapper/Longline Shark Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 5, 2017

 

Weather Data from the Bridge (get data from bridge)

Latitude: 29 degree 36.0 N
Longitude: 86 degree 10.1 W
Sea wave height: < 1
Wind Speed: 7 kts
Wind Direction: 185
Visibility: 10 nm
Air Temperature:
Barometric Pressure: 1016.3
Sky: BKN

Science and Technology Log

The Oregon II has two sets of crew – the ship’s crew headed by Captain Dave Nelson and the science crew headed by Lisa Jones. Captain Dave and Lisa work closely together making decisions that impact the survey. The ship’s crew keeps us afloat, fed and ultimately determines where we go based on weather. The science crew, well you guessed it, is focused on the science and collected data at predetermined sampling sites.

This post will look at some of the science happening on board. On board are four NOAA scientists as well as other volunteers and researchers that are helping with this survey. NOAA’s focus on this survey is all about sharks and snapper. We are collecting data on what we haul up from the longlines as well as abiotic factors including temperature, depth of line, dissolved oxygen, and salinity of the water. The data is entered into a computer and becomes part of a larger data set.

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NOAA parasitologists Carlos and Brett

Two researchers on board working as volunteers are Brett Warren and Carlos Ruiz. They are parasitologists meaning they study parasites that sharks and other organisms carry. A parasite is an organism that lives off other organisms (a host) in order to survive. They are finding all sorts of worms and copepods embedded in the nose, gills and hearts of fish and sharks. These two spend much of their time using microscopes to look at tissue samples collected.

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Brett looking for parasites

In speaking with Brett, the life cycle of parasite can be simple or complex. The simple direct life cycle is when the parasite spends its entire life on the host organism. A complex indirect life cycle for a parasite is when the parasite reproduce, the young hatch and swim to an intermediary host, usually a snail, mollusk or polychaete. This is where it gets really cool, according to Brett. It’s the intermediate host where the parasites asexually reproduce by cloning themselves. Next, the parasite leaves the intermediate host and swim to their final host and the process starts all over again. From a parasite perspective, you can see how difficult it would be for an indirect life cycle to be completed, because all the conditions need to be right. Brett is studying flatworms that have complex lifecycles and Carlos is studying copepods that have direct life cycles.

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Can you guess what this is? Answer in the comments and first right answer gets a prize!

Their main focus on this survey is to discover new species of parasites and understand the host- parasite relationship.

 

Personal Log

The past few days have been slow with only a few stations a shift. We have hauled up some sharks, eels and even a sharksucker fish. One station had nothing on the 100 hooks set! Talk about getting skunked. As we move west I am hoping we get to see more sharks as well as more variety. Other wildlife spotted include dolphins, jellyfish and birds.

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Finding the length of a sharpnose shark

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size of hooks we are using

Did You Know?

Just because it’s a parasite doesn’t mean it harms the host. Some just live off of another organism without harming it.

 

Question of the day:

What are the two types of life cycles a parasite can have? (hint: read the blog)

Brad Rhew: The Sounds of the Sea, July 31, 2017

NOAA Teacher at Sea

Brad Rhew

Aboard NOAA Ship Bell M. Shimada

July 23 – August 7, 2017

 

Mission: Hake Fish Survey

Geographic Area of Cruise: Northwest Pacific Ocean, off of the coast of Oregon

Date: July 31, 2017

 

Weather Data from the Bridge

Latitude: 44 49.160 N
Longitude 124 26.512

Temperature: 59oF
Sunny
No precipitation
Winds at 25.45 knots
Waves at 4-5ft

 

Science and Technology Log

TAS Rhew 7-31 acoustics lab2

Inside the acoustics lab

The scientists on the Hake survey project are constantly trying to find new methods to collect data on the fish. One method used is acoustics. Scientists Larry Hufnagle and Dezhang Chu are leading this project on the Shimada. They are using acoustics at a frequency of 38 kHz to detect Pacific Hake. Density differences between air in the swimbladder, fish tissue, and the surrounding water allows scientists to detect fish acoustically.

The purpose of the swim bladder in a fish is to help with the fish’s buoyancy. Fish can regulate the amount of gas in the swim bladder to help them stay at a certain depth in the ocean. This in return decreases the amount of energy they use swimming.

TAS Rhew 7-31 echosounder

The screen shows the data collected by the echosounder at different frequency levels.

Larry and Chu are looking at the acoustic returns (echoes) from 3 frequencies and determining which are Hake. When the echosounder receives echoes from fish, the data is collected and visually displayed. The scientists can see the intensity and patterns of the echosounder return and determine if Hake are present.

The scientists survey from sunrise to sunset looking at the intensity of the return and appearances of schools of fish to make the decisions if this is an area to fish.

TAS Rhew 7-31 scientists Larry and Chu

Scientists Larry Hufnagle (left) and Dezhang Chu (right) monitor the nets and echosounder while fishing for hake.

The ultimate goal is to use this data collected from the echosounder to determine the fish biomass. The biomass determined by the survey is used by stock assessment scientist and managers to manage the fish stock.

Personal Log

Everyday aboard the Shimada is a different experience. It has been amazing to be able to go between the different research labs to learn about how each group of scientists’ projects are contributing to our knowing more about Hake and marine ecosystems. My favorite part so far has been helping with the sampling of Hake. Some people might find dissecting fish after fish to determine length, sex, age, and maturity to be too much. However, this gives me an even better understanding and respect for what scientists do on a daily basis so we can have a better understanding of the world around us. We have also caught other fascinating organisms that has helped me explore other marine species and learn even more about their role in the ocean.

Even though the wind is a little strong and the temperatures are a little chilly for my southern body I wouldn’t trade this experience for anything…especially these amazing sunsets…

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View of sunset over the Pacific Ocean from NOAA Ship Bell M. Shimada

Did You Know?

Before every fishing operation on the boat we must first do a marine mammal watch. Scientists and other crew members go up to the bridge of the boat to see if any mammals (whales, seals, dolphins) are present near the boat. This is to help prevent these animals from being harmed as we collect fish as well as making sure we are not running a risk of these mammals getting caught in the fishing nets.

Fascinating Catch of the Day!

Today’s fun catch in the net was a Brown Catshark! These creatures are normally found in the deeper parts of the Pacific Ocean. They are typically a darker brown color with their eyes on the side of their head. Their skin is very soft and flabby which can easily lead to them being harmed. They have two dorsal fins and their nostrils and mouth on the underside of their body. One of the sharks we caught was just recently pregnant.

 

TAS Rhew 7-31 catshark egg sack string

This catshark was recently pregnant; the yellow stringy substance is from an egg sack.

Notice to yellow curly substance coming out of the shark? That is from the egg sac. Sharks only produce one egg sac at a time. It normally takes up to a full year before a baby shark to form!