Sunday, May 26, 2013

The End (But Not Really)

Little Baby Tuna Hotsauce (homemade!)
Well, we said goodbye to the Foster yesterday morning. We pulled into Key West around 0900, unloaded our mountain of gear, and drove back home to the Southeast Fisheries Science Center in Miami. Some of our Spanish and Mexican scientists are staying on for a few more days, as the 37th Annual Larval Fish Conference is being held in Miami starting next weekend. In fact, several of the scientists on the cruise will be presenting at the conference!

Our findings support the theory that bluefin don't normally spawn in Bahamian waters -- our total bluefin count was less than twenty (sampling in the Gulf of Mexico or the Mediterranean finds hundreds of larval tuna). The work isn't over though -- there are boxes of samples still to be sorted, and isotope/chlorophyll analyses waiting to be completed. Although it would have been exciting to find a formerly unknown spawning ground, there's a lot that can be learned from the cruise data that can help to refine current fisheries practices. There are also a lot more questions to be answered!

Thank you to all of the people who made this trip possible: The NOAA corps who handled all operations, drove the boat, and took all the station changes in stride; the mechanics who fixed the winches (and everything else) and made sure the ship was running smoothly; the stewards who kept us fed, made us Baby Tuna Hotsauce, and provided copious amounts of chocolate; the survey technicians who ran the CTDs and were great company on and off the ship; the winch operators for dealing with our many accents and radio quirks; and the electrical technicians who solved all the problems with the CTDs, radars, MOCNESS, and handled all computer business.

On a personal note: This was an incredible experience for me (I wish I was back on the ship already!). I learned a tremendous amount during the three weeks we were onboard, in addition to having a blast with everyone on the boat. It was a great group, and I couldn't have asked for a better introduction to research at sea. I now have a better understanding of why the samples I sort the rest of the year are important as well as the amount of work that goes into getting them. I'm hoping that I'll have more opportunities like this one in the future!

May the fish be with you!

Our Spanish scientist Raul out on deck
ET (electrical technician) K. Martin and
one of the survey techs S. Martin
working on the small CTD



Wednesday, May 22, 2013

Fish Findings

Earlier I wrote a post about some of the cool plankton we found during leg 1. We've sorted about 60 more samples since I wrote that -- and we've found a lot of really interesting organisms in the process! Not surprisingly, most of us get the most excited over the fish we find, so an ichthyo-oriented post was in order. I included a picture of the adult form of each fish with its larval picture -- in some cases, the adult may not be the same species as the larvae depicted, but should be a good representative of what the adult might look like.

All photos were taken using a microscope camera with the specimen in seawater to preserve color and pigments.

P.S. Our cruise is almost over, with the current plan putting us into Key West on Friday morning. This is the last night shift!

Larval Lionfish
Lionfish (Pterois volitans). Lionfish are an invasive species in the Atlantic and have no natural
enemies in this region. They also have poisonous spines and a voracious appetite for
native reef fish.
Larval sargassum fish
Sargassum fish (Histrio histrio). Sargassum fish are in the frogfish
family, and have a lot of appendages that help them blend
in with the sargassum they live in.

Larval ribbonfish
Ribbonfish (family Trachipteridae). Ribbonfish are deep-dwelling fish that come up closer to the surface at night. They have a really large dorsal fin and a very small mouth. As adults, they have a skinny, elongated body.

Larval pipefish
Pipefish (family Syngnathidae). Pipefishes are in the same family as seahorses and seadragons. They have elongated snouts with fused jaws, forming a tube-like mouth that they use to suck up food. Pipefish don't have traditional scales; their skeleton has evolved to form bony plates that encase their bodies. 
Fish eggs
Fish eggs. In the left photo you can see the embryo's eyes at the bottom right corner; this egg was still alive when this photo was taken. In the right image, the dark bands in both eggs are the growing fish.

Lizardfish larvae
Lizardfish (family Synodontidae). Lizardfish are common
on reefs and live on preferably sandy bottoms. As
adults, their coloration helps them blend into the
sand. 

Barracudina Larvae
Barracudina (family Paralepididae). Barracudinas are deep-
dwelling fish that come up near the surface at night
to feed on plankton. Despite the name they are not closely
related to barracudas. 

Slender sunfish larvae
Slender Sunfish (Ranzania laevis). This fish is a type of mola, a specialized fish that lacks a
typical fish shape. They are typically oceanic and grow up to 1 meter in length.

Swordfish larvae
Swordfish (Xiphias gladius). Swordfish are highly migratory game fish. By adulthood, their bill extends only from the upper jaw and probably use it to slash prey to make it easier to swallow. They are one of the fastest fish in the oceans.
Filefish larvae
Filefish (family Monocanthidae). Filefish are common on reefs are have rough, sandpapery skin that
gives them their name. The spine on their top of their heads can be locked, preventing predators from easily removing them from crevices in the reef. They are closely related to triggerfish and pufferfish.


All photos are the property of NOAA. Reproduction, manipulation, or downloading are prohibited without permission by Kat Dale. Thanks!

Monday, May 20, 2013

Stay Classy, Not Trashy

Trash found over three stations.
Trash (mostly plastics) found during one shift.
Most people know about the huge amount of trash floating around the oceans. But it doesn't really sink in until you sort a plankton sample and find a dish full of plastic, fishing line, and other trash. Plastics make up 90% of the trash in the oceans. You might think that once plastic products break down into tiny pieces they won't be as harmful and will degrade quickly -- but these chips remain floating at the surface for up to 400 years, and don't degrade as quickly as they do on land. They can be mistaken for fish eggs by other creatures (even birds!), and when ingested can trick animals into thinking they aren't hungry by filling up their stomachs. Sea turtles are a poster child for this, as they often confuse floating plastic bags for the jellyfish they eat. In addition to causing animals to starve, plastics and other debris can block digestive systems, cut up internal organs, release toxins, and cause abnormal behaviors. Fishing line, nets, and other larger trash items act as traps for organisms of all sizes. Add cigarette butts, paper, styrofoam, metal cans, and glass to the equation, and you have a really large trash problem.

We've found a lot of trash in floating sargassum. Sargassum is a seaweed that forms clumps and creates a home for a ton of different species. But these clumps also trap debris, making these valuable habitats unhealthy for the range of fish, turtles, birds, mammals, and invertebrates that depend on them.

What can you do?
  • Avoid buying plastic products, or buy goods that use less packaging.
  • Recycle not only plastics but also glass, cardboard, paper, your clothes, anything!
  • Buy things in bulk.
  • Bring your own cloth bag to the grocery store.
  • Avoid putting any trash down the drain, as there's a good chance it'll end up in the oceans.
  • Use environmentally friendly cleaners.
  • Dispose of fishing line correctly.
  • When you go to the beach, pick up the trash that you see lying around.
  • Volunteer your time!

For more info, see:

Also speaking of styrofoam ... we tied up our markered cups and sent them down on the CTD to 2,723 meters (8,933 ft)!
S. Privoznik ties the cups to a mesh bag.
S. Privoznik zip-tying the cups to the inside of J. Lamkin's
laundry bag.

The shrunken cups
Our shrunken cups (they're upside down). Compare to the photo
seen in Scientists Are Fun 




Sunday, May 19, 2013

And Then There Were More...

We've found a few bluefin tuna larvae in the last few days, including one station with four! That may not seem like a lot, but in reality finding any bluefin is a big event because we have been finding none at most other spots. We think these larvae were probably born in the Bahamas, not transported from elsewhere, because they're only 5 mm long or less -- that means that they're just a few days old, and couldn't have come from far-off lands like the Gulf of Mexico or the Mediterranean Sea. This means that at least a few tuna adult spawned in the region (North of the Bahamas). Were these adults lost, testing out a new spawning area, or just being rebels? More work is needed! Stay "tuna-ed" to see if we find more bluefin over the next week and a half (FYI, in the Gulf of Mexico, we find hundreds of bluefin tuna larvae in our samples). 

P.S. You might be wondering how we identify tuna larvae as a bluefin tuna vs other species of tuna. It gets to be a difficult task sometimes, as the only differences between the skipjack, blackfin, yellowfin, and bluefin tunas are tiny pigments, some of which are barely noticeable spots. At other times DNA is the only way to correctly identify a tuna to the species level -- a lot of specimens lose their heads, tails, or other crucial portions of their bodies after getting beat up by the currents, our nets, by other organisms, or through handling. Compare the two below and see if you can tell them apart -- it takes a trained eye, some patience, and a powerful microscope to identify to the species level. These larvae were photographed in seawater to preserve color and pigments!

Larval skipjack tuna ID
Skipjack Tuna (Katsuwonus pelamis)
This guy has black pigments both before and after his brain (two black arrows) ... he also has one black spot on the lower part of his tail but never has any pigment on the top of his body or on his chin.
Larval bluefin tuna ID photo
Bluefin Tuna (Thunnus thynnus)
Compared to the skipjack above, the bluefin doesn't have pigment in front of his brain or on his chin. He does have spots on both the top and bottom of his body. 

All photos are the property of NOAA. Reproduction, manipulation, or downloading are prohibited without permission by Kat Dale. Thanks!

Scientists Are Fun

The last few posts were pretty science/tech-heavy ... so I thought I'd show everyone that we actually do a lot more in our free time than sit around discussing the merits of different CTDs (if you'd like to read those posts about CTDs, nets, and other gear, go here and here). If you want to view any photo larger, just click on it! For captions, go to the bottom of this post.

Lucky Sea Monkey Clyde
1

E. Malca Go Pro
2
NF1304 PicturesNIck Mitchell
                                                 4


3                          
5

Styrofoam cups for CTD
6

Jake and Kat With Sargassum Beards
7
From Top:
1. Clyde, our lucky sea monkey, decked out in S. Privoznik's birthday gear
2. E. Malca hooked up her Go-Pro to some of the nets! She was pretty excited about her setup.
3. The official NF1304 candy jar!
4. N. Mitchell, a survey technician on the Foster, had his hair braided in Nassau.
5. We celebrated S. Privoznik's birthday while on the ship!
6. A selection of the many styrofoam cups we markered up! We'll send these down on the CTD to about 1000 m -- when they come up, they'll be shrunken down to about 1/3 of their original size.
7. Showing off our facial hair (or facial sargassum)

Friday, May 17, 2013

Gadgets

Collecting water from the rosette CTD
Taking water samples from the rosette CTD
SBE19
SBE #19 -- the CTD used on the mini-bongo and
sub-surface nueston nets
We use a lot of other gear in addition to nets while on the ship. One of most important are our CTDs, or Conductivity-Temperature-Depth devices. These can range from small cylindrical models to large frames that have water collection bottles (Niskin bottles) attached to them. Each one reports data back to the ship via a wire connecting to an onboard computer. We have one of the less involved versions attached to our subsurface neuston frame and use it to monitor the depth of the net. The rosette CTD goes down to hundreds of meters in depth and measures not only salinity, temperature, and depth but also chlorophyll and dissolved oxygen; its attached bottles are triggered by one of the Foster's survey techs at a computer to collect water at 50 meters, the surface, and wherever the chlorophyll maximum is. 

Those water samples taken by the rosette CTD are filtered using a vacuum pump onto filter pads. These pads are taken and used to measure the concentrations of various chlorophylls in the water column. 

A third device we use on every net tow is a flowmeter. This piece of gear looks like a tiny rocket and hangs in the net frame. We record the numbers on the side at the start and the end of the tow and use these, along with the size of the frame, to calculate the amount of water moving through the net. 

Last but not least -- drifters! We have a pile of these large floating balls that we deploy at areas we think have an interesting current pattern. They have a long "sail" that hangs down through the water column and is supposed to prevent movement due to wind and aid with movement due to currents. A transmitter inside the drifter connects to satellites which relay its position back to us. From this information we can track direction and speed of currents. 


Flowmeter
Flowmeter
Taking the filter pads off of our chlorophyll vacuum
K. Doering removing the filter
pads off the vacuum pump
to save them for further
analysis. 
Drifter
Drifter. The ball floats on top of the water while the blue sail
(stretched out to the left) hangs down below.



Wednesday, May 15, 2013

Port and Plans

On Monday morning we departed for leg 2 of cruise NF1304 after spending a few days in Nassau, Bahamas. It was refreshing to get off the boat and eat local, shop, snorkel, and hang out on the beach for a few days. We hung together as a group for the most part, although various people went SCUBA diving, to the Pirate Museum, or other landmarks on their own. Our science crew also changed during this time, with two researchers leaving and four more coming on. The new group includes two Mexican scientists from ECOSUR and a Spanish scientist from IEO (Instituto Espa√Īol de Oceanograf√≠a), as well as one more hailing from a NOAA lab on the west coast of Florida.

Leg 2 scientists
Most of the science party for leg 2 minus our
lead scientists J. Lamkin, E. Malca, and
S. Privoznik
Leg 1 ended with us having found only two definitive bluefin out of all the tuna larvae we saw. On this leg, we're going to try sampling further north (if you'd like to follow our track, go here). Bluefin tuna spawn in cooler water  near the surface (a shallow thermocline). Often these occur on the edges of cold-core rings (eddies) that form when cold waters upwell, thus creating an independent pocket of rotating cool water that can travel on its own. On leg 1, we sampled waters that remained relatively warm to very deep depths, but we're now journeying north to look for   waters where the cool water is shallow. We have been using a CTD (conductivity-temperature-depth) to monitor conditions.

The common belief held by many tuna scientists and fisheries managers is that bluefin don't spawn in Bahamian waters -- but tagged adult tunas have been known to visit and hang around in this part of the Atlantic without any side trips to either the Mediterranean or the Gulf (the two known spawning grounds). If we find bluefin larvae during this second leg, it would introduce the possibility of bluefin spawning in a third location, thus affecting bluefin fisheries projections. 

We're hoping for better luck this second leg! It's started off with a few equipment issues and some rough seas, but we found the first bluefin of the leg this morning so we're excited for future findings.


Leg 1 stations
All of the stations we completed during leg 1 of our cruise. (To see the entire path, go to the
NOAA ship tracker website).

The science party plus a few others at a local fish fry
The science party, the Foster's two survey techs
and electrical technician, and our hostess at
the local fish fry. 
NOAA ship Nancy Foster at dusk
Our floating hotel docked at the
cruise ship terminal in Nassau.

Friday, May 10, 2013

Life on the Water

Steel beach
"Steel beach" outside the bridge
Boat life is very simple. You lose track of the days. Cell service is nonexistent. Internet is iffy. You wake up for your shift, work for 12 hours, and then crash. But the Nancy Foster is a large enough boat that you can always find a spot to relax during down time between stations. Someone somewhere even created a "steel beach" up outside the bridge complete with a picnic table, potted plants, and lounge chairs more comfortable than your bed.

There are two other groups onboard, the NOAA Corps who do the driving and oversee all operations, and the engineers/electricians/ stewards who run the winches, make the food, hook up electronics, fix everything, etc. The science party and these other two groups communicate constantly to make sure everything is running the way it should be and to fix the inevitable problems that crop up!

Sometimes the swells come rolling through and the flat-bottomed Foster makes every wave seem like a roller coaster ... on those days, it's a lot more difficult to sleep and work (and practically everyone in the science party feels queasy, haha).

There are always surprises, like the flamingo that the bridge supposedly saw land on the boat the other day; we've also seen flying fish and dolphins jumping in the boat's wake. One afternoon someone saw what we think was probably an adult Mahi Mahi go by … another time a juvenile turtle floated past in the sargassum. And speaking of sargassum, we caught a sargassum fish (Histrio histrio) in one of our tows the other day. We released him (after taking about a thousand photos of him, first!)
Sunrise
Sunrise from the boat -- this is totally
normal but it never loses its magic!

Sargassum fish
Sargassum fish!





Thursday, May 9, 2013

Nets on Nets on Nets



Sub-surface Neuston Net
Nueston net.
We use three nets to catch plankton. The first is the sub-surface Neuston, a 1 meter by 2 meter frame with a long conical net attached to it. The plankton collects in a plastic tube at the end called the "cod end." With the help of the winch operator, we do a few dips with the net to 10 meters (~30 feet). So far, this is the most effective method for finding tuna, and often the plankton from these tows is sorted right on the boat by one of us.

The second net, called the Mini-Bongo (it looks just like its name) is made up of two connected PVC pipes that each have a net and cod end attached to them. One net has a mesh that captures the small stuff; the other has larger mesh that keeps in the bigger plankton. These samples will be used to examine what tuna are eating and to create a food web from stable isotope values of nitrogen. 

The last net is the MOCNESS (also known affectionately as the MOCNESS Monster or the Franken-MOCNESS). This net can be really useful, as it has a unique system where plankton samples from different depths can be taken on a single tow by opening and closing various nets. It's taken us many hours to set it up and the system is very heavy, complicated, and had some set-up issues in the beginning, but in the last few days we've finally gotten it working and have done several successful MOC tows. If you're interested in learning more about the MOCNESS, visit WHOI's page.

And in case you're wondering (I bet you are!), MOCNESS stands for Multiple Opening and Closing Net Environmental Sensing System.

Mini bongo
Mini-bongo, with two nets attached to
the "bongo" portion.

MOCNESS Diagram
Diagram of the MOCNESS as it flies in the water
Plankton in a Sieve
Plankton collected in a sieve after a
subsurface neuston tow



Tuesday, May 7, 2013

In Search of Plankton

And now for the real deal -- what we're finding in our samples! So far there haven't been a lot of definite bluefin but we have found other tunas and billfish, as well as various planktonic characters like lobsters, different fish, crustaceans, worms, snails, jellies, etc. We've also found a lot of trash, mostly plastics (more on that in a future post).

We took all of these photos using a microscope camera. 

By clicking on a photo you can view it in a larger window.


Bluefin tuna larvae
Bluefin Tuna (Thunnus thynnus) - What we're looking for!
cephalopod
Cephalopod
larval sunfish (molidae)
Sunfish (Molidae)



Larval mahi mahi
Mahi Mahi (Coryphaenidae) 
planktonic worm
Bristleworm
Pufferfish larvae
Pufferfish (Tetraodontidae)

Myctophid
Myctophid (Myctophidae)
Euphausiid and a decapod
Krill (euphausiidae) and a decapod

Billfish larvae
Billfish (Istiophoridae)
Lobster larvae
Lobster larvae
All photos are the property of NOAA. Reproduction, manipulation, or downloading are prohibited without permission by Kat Dale. Thanks!