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