Natural light, fangs, and the g value

Sundown at sea viewed from stern of the Henry Bigelow

“Nothing beats the views from the boat1” Photo by NOAA/NEFSC/Cassie Fries

Hello from the ocean! I’m Cassie Fries, a recent graduate from Stony Brook University. I’m part of the oceanography crew aboard the Bigelow, and this is my first time out on a research vessel. It took a few days to adjust, but I can finally say I have my sea legs.

This has been an incredible opportunity for me, since I’m learning real world applications for different areas of marine research. Being on this cruise has taught me so much in just two weeks; and nothing beats the views from the boat!

Oceanography is on the night shift, which means we find all types of creatures in our nets. For me, a lot of these creatures are foreign, or it’s my first time seeing them not in a photo! Sometimes, we even find things that we cannot identify at first. It changes with stations, but we get larval fish in our nets.

Shiny silver and blue fish with sparkling light organs

Lanternfish. Photo by NOAA/NEFSC/Cassie Fries

We have gotten Myctophids, which are commonly known as Lanternfish for their bioluminescence. At night, you can see their photophores along their body, which shimmer in the net. We have caught them at all sizes since they are one of the most common fish in the deeper layers of the sea.

Big jawed fish with fangs

Dragonfish. Photo by NOAA/NEFSC/Cassie Fries

We have also caught crazy looking fish, like the Dragonfish! He is another deep-sea fish and he has a barbel that acts as a lure for him to attract prey.

As part of the oceanography team, it’s my job to titrate and find the g value of these animals, which is the ratio of density of the animal relative to the density of seawater. We do this by mixing seawater and a denser solution to find when the animal is neutrally buoyant . This is an important value to get, as bioacousticians need to model how much sound these animals scatter, which depends on how dense they are relative to the ocean.

We don’t just see fish in our nets, we also see small pteropods, salps, heteropods, amphipods, jellys, and larval crustaceans. There’s a whole lot going on in the water, especially on the zooplankton level. There is never a dull night with the oceanography crew!

Cassie Fries, Oceanography Team

Aboard the NOAA Ship Henry Bigelow

 

Animal surveillance

In our quest for turtles, we have traveled far and wide in the past 13 days. From Nova Scotia to New Jersey, we have kept almost constant watch during daylight hours in order to spot turtles basking in the sun, and in the process, we have seen many different marine creatures.

On July 8th, we awoke to pilot whales curious about the ship and they accompanied us for the entire morning.  A couple of days later, we crossed the Hague Line on the shelf of George’s Bank. Very soon after, we started seeing sperm whales,  some of them breaching – a behavior where they launch themselves  entirely out of the water landing in a large splash that we can see miles away! Sperm whales can dive to very deep depths and tend to inhabit waters around canyons. This habitat also attracts beaked whales, including Cuvier’s beaked whales which we also spotted. We saw more pilot whales and small groups of bottlenose dolphins, many of them jumping out of the water as well. Meanwhile, above the surface, we have encountered many pelagic seabirds that are expected in this area, including the shearwater, storm petrel, and gull species. This day we also had south polar skuas flying around the ship.

 

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We turned south on July 12th toward the mid-Atlantic and started to encounter larger numbers of common dolphins characterized by the hourglass pattern on the sides of their bodies. We have seen pods numbering in the hundreds out here so far, and they have given us great looks when they come in close to the ship.

Of course, the focus of this cruise is to find loggerhead turtles and we did encounter quite a few on July 13th. We spent a few days in the warmer waters off New Jersey working these animals where we also spotted a few leatherback turtles.

On July 16th, we turned to work our way north again and started our day with flat calm waters, the best sighting conditions so far. We saw many common dolphins, including a group of around 500, bottlenose dolphins, and many groups of Risso’s dolphins. The Risso’s are darker when they are younger, and lighten up (and gain some impressive scars) as they age.

In addition to the reptiles, mammals, and seabirds that we tend to see at the surface, there are of course, many fish species in the ocean. We have seen a lot of ocean sunfish along our entire track, a glance at a couple of rays, and also a few shark species including hammerheads, basking sharks, and three whale sharks on July 16th! This was a new species for almost everyone on board, and it took us a second to understand what we were seeing! Whale sharks are the largest fish, reaching lengths of over 40 feet, and feed on zooplankton by filter-feeding. They are characterized by their size, but also by the spots on their dorsal body which helped us identify the species.

Only a few days left out here, but many chances yet to spot additional animals.

Leah Crowe and Lisa Conger
NEFSC Protected Species Branch, aboard the NOAA ship Henry B. Bigelow

More Tales from the Night Shift

Predator worms, spines with eyeballs, and a mystery

I’m Hannah Blair, a graduate student at Stony Brook University, aboard the NOAA Ship Henry Bigelow for the 2017 sea turtle and cetacean cruise.  This trip is my first foray into the world of zooplankton identification. Each night, we sift through the contents of targeted zooplankton trawls, pull individual plankton out of each sample collected by the nets, and measure and photograph what we find. I’ve slowly been learning to recognize the categories these tiny animals belong to. For example, we pull up lots and lots of chaetognaths, or arrow worms, a group of predatory worms!

Tiny transparent marine worms

Carnivorous, predatory arrow worms that prey on other plankton. Photo by NOAA/NEFSC/Cassie Fries

We find many kinds of gelatinous animals, such as jellyfish, as well as a number of crustaceans, like these adorable bug-eyed megalops, an early crab life stage.

Tiny bright red-orange early life-stage crab

Megalops, early life stage crab. Who doesn’t love those googly eyes? Photo by NOAA/NEFSC/ Cassie Fries

We also find fish larvae of various sizes and shapes, from the wide and flat larvae of flounder to fish so small they look like spines with eyeballs. After going through a few hauls, you start to recognize what animal belongs with what category.

And then, this guy appeared:

Sea slug,

There’s no zooplankton too odd for Betsy Broughton’s mad identification skills. Mystery solved and sea slug unmasked. Photo by NOAA/NEFSC/Joe Warren

The first time we saw it, we dismissed it as an unidentifiable piece of another animal. But then we got another, and another. When, on the third night, we got six in one haul, we had to stop and take a closer look.

As someone who’s spent many an hour identifying species, whether for classes or for surveys (or for fun), I am familiar with the frustration of not being able to figure out what species an animal or plant is, and the satisfaction of finally pinning it down. However, at first we couldn’t even determine what group of animals we should start narrowing down from! Was it a flatworm? Some type of echinoderm (starfish and relatives) larva?

After spending hours searching through identification keys and checking our trusty friend Google Images, our resident marine zooplankton expert Betsy Broughton was able to track it down. Meet Phylliroe bucephala, a free-swimming nudibranch!

Nudibranchs are a type of sea slug, and are a highly varied group. Searching the term (which I highly recommend, I love these guys) will bring up many photos of brightly-colored tropical sea slugs, crawling around on the ocean floor. But Phylliroe is pelagic, which means it lives up in the water column, swimming much like a fish as it searches for tasty jellyfish prey. Check out this link to see images and even a video of them swimming through the water!

We’ve found a lot of cool animals in our trawls, but this one is definitely my favorite so far.

Cheers,

Hannah Blair

Oceanography Team, aboard the NOAA ship Henry B. Bigelow

 

Turtle Team and Oceanographers Do Mix

Bigelow scientific team at dinner

Here’s the team, at dinner before the first night on the boat: (around the table from the first on the left) Leah Crowe, Cassie Fries, Joe Warren, Eric Matzen, Michael James, Betsy Broughton, Samir Patel (obscured), Liese Siemann, Hannah Blair, Chrissy Hernandez).

Samir Patel here, turtle biologist aboard the Henry Bigelow for the 2017 Turtle and Cetacean cruise.   I am fortunate to have this opportunity to collaborate with many scientists from varying fields. As a sea turtle biologist, I do not typically conduct oceanographic surveys, or deploy acoustic recording devices, or sift through plankton in search of larval fish. However, we’re doing all of that.  This combination of researchers from government agencies, academia and non-profits means a cruise for turtle research becomes an opportunity to successfully integrate many research goals.

For the turtle research itself, the team consists of scientists from NEFSC, Department of Fisheries and Oceans-Canada, and Coonamessett Farm Foundation (CFF). The oceanographic work includes researchers from NEFSC, Stony Brook University, Woods Hole Oceanographic Institution, and CFF.

The goal of the sea turtle research is to sample a population of turtles that is typically difficult to encounter.  Using our combined resources, we hope to achieve this difficult goal. We expect turtles in this region to be smaller and forage higher in the water column than those encountered in the Mid-Atlantic Bight, for example.  There, through collaboration with NEFSC and CFF, we have caught and tagged more than 100 loggerhead turtles. We also expect the density to be lower than in the Mid-Atlantic Bight, thus communication and additional collaboration with local fishermen is key to providing intel on where we might encounter loggerheads.

 

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For the oceanographic sampling, collaboration allows the use of the same tools to help solve multiple problems. By towing neuston and bongo nets that are sampling at varying parts of the water column, several research questions can be addressed. First, what plankton are found in these regions and under these environmental conditions, specifically, in the frontal zones between warm and cold waters? Second, are there any particular fish larvae found in the plankton that would help us improve understanding of the spawning locations? Third, can we use video recording to measure the presence of gelatinous zooplankton in the water, a major food source for leatherback turtles and, occasionally, loggerhead turtles as well?

If not for the diversity of collaborators, our goals and objectives during this leg would be very limited; however through strong collaboration, we can address many research questions and bring many scientists together.

Samir Patel, Coonamessett Farm Foundation

Aboard the NOAA Ship Henry Bigelow

Oceanography After Dark

Oceanography After Dark

July 10, 2017 — Hello from the Night’s Watch !  Unlike Jon Snow and his buddies on Game of Thrones, the night watch  on the ship are the folks who work between sunset and sunrise while the turtle-spotting scientists (and probably you) are asleep. It takes a day or two to get your body/brain to switch over to night-time as your working time, but a lot of very cool stuff happens at night.

I’m a bioacoustician. That means I use sound to study the marine environment.  One of my primary tools is an echosounder, which works much like a fish-finder or depth-finder you may have seen on a boat at some point.  Our equipment works similarly to those, it sends out a short pulse of sound (“a ping”) and then we listen for the echoes that come back. The ship we are on (NOAA’s Henry Bigelow) has a very nice, five-frequency, hull-mounted echosounder and as we drive around the ocean, we can see where different fish and plankton (small animals that can’t swim against a current very well) are located in the water column.

art-1_opt

This is an echogram showing where organisms are located in the water column. The five windows show the five different frequencies (or wavelengths) of sound. Different wavelengths can detect some animals better than others. The blue dots represent a layer of animals that are located at different depths in the upper 100 m of the water column. We try to target a specific layer (or depth) when we deploy our nets). Photo Courtesy Joe Warren/Stony Brook University

We use this information to determine at what depths we send our nets down to collect samples of these organisms.  And there’re A LOT of very cool animals that live in the ocean – most of which you probably have never seen or heard of.  One of my students will be blogging about some of these later on.

People washing out large plankton net on deck

Scientist are washing down the net after we bring it back on board the vessel, so that we make sure that we get all the animals in the net into our sample that we process inside the boat in the wet lab. Photo Courtesy Joe Warren/Stony Brook University

Once we have these animals on the boat, we take a small number of them and measure their density (how much they sink or float relative to seawater) and their soundspeed (how fast sound moves through them), and photograph them with a ruler for scale so we know their shape and size.  We use these data to determine how much sound would reflect off a single animal.  With this information, we can convert the echoes (blue dots in the echogram) to how many animals there were beneath the boat.  This process can get very complicated if there are lots of different types of animals in the water – but in many cases we can use the acoustics to map out where the animals are relative to the different types of water we’re encountering.

In our nets, we find lots of different animals :

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(Photos Courtesy Joe Warren/Stony Brook University)

Our cruise track for the past few days has us (at night) going in and out of a warm core ring, which is a chunk of water from the Gulf Stream (so it’s warm and salty) that has spun away from the Gulf Stream and is now traveling up along Georges Bank (southeast of Cape Cod).  What’s really interesting about sampling this warm core ring is that you can find completely different sets of animals when you do a tow inside or outside of the ring.  So you can find tropical species in one tow, and more typical species for coastal New England in the next tow depending on where the ship is.

Color coded chart of ocean water surface temperatures off the Northeatern U.S.

This is a map of sea surface temperatures that are collected by a satellite in space, and made available by scientists at Rutgers University. The left side of the orange-blob of water at the far right-hand side of the image is where we are working currently. This satellite can’t see through clouds so the maps that we get are a function of the weather conditions as well. (Photo Courtesy Joe Warren/Stony Brook University)

Thanks for reading about our science,

Joe Warren

Stony Brook University

Aboard the NOAA Ship Henry B. Bigelow for the 2017 Cetacean and Turtle Cruise