2017 Spring Bottom Trawl Survey

Leg I: Sometimes It’s All About the Little Things

All photos in this post by NOAA/NEFSC/Christine Kirkun

Fish identification is an important part of the job on the bottom trawl survey.  When the catch comes down the sorting belt, it is our job to separate them into baskets, buckets and pails.  Some fish look extremely different from each other.  Others may appear almost exactly the same, especially if it’s your first time looking at them.  The sorting belt is constantly moving so even the most seasoned scientist may get their eyes crossed as they pick through the unsorted catch.

The people at the top of the line typically pick up the large animals, such as dogfish, skates, rays, and goosefish, or a single fish, if the catch has a lot of a particular species, such as haddock, Acadian redfish, or silver hake.  This makes it easier for the people at the bottom of the line to pick up the smaller animals, such as juvenile fishes, squid and crabs, and the more difficult fish to pick up, such and windowpane and fourspot flounders.  Ultimately, if there are two species that look similar, and you’re unsure, you can ask someone or, if it’s busy, place them both in a bucket to be sorted separately at the end.

pic 1_spiny dog back-smooth dog front_opt

A spiny dogfish and a smooth dogfish

Dogfish have been everywhere so far, and we’ve caught a lot of them.  Spiny dogfish is our most commonly caught shark, but there are areas where the smooth dogfish is abundant as well.  At first glance, these two sharks may seem identical, but on close inspection, it is quite clear that they are very distinct from each other.  But remember, we’re not looking at them, perfectly lined up and still.  They are moving down the sorting belt all mixed together with the rest of the catch.  In this case, the sorter looks specifically for the presence or absence or the dorsal spines, although on closer inspection, it is clear the shape of the head, eyes, and caudal tail are very different.

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The telltale spine

The two main sea robins we’ll find are striped and northern.  While both species can reach into the 20cm range for length, the northern sea robin is usually smaller.  Much about them looks very similar except for the prominent dark lateral stripe of the, you guessed it, striped sea robin.

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A striped and a northern sea robin

Squid is also a very common species caught along the entire survey track.  Loligo, or longfin squid, is most dominantly in our survey, although it’s not uncommon to have a mixed catch with Illex, the shortfin squid.  Right away, there is an obvious color difference, with the Illex being more golden/orange and the Loligo a deep red/maroon or light purple, depending on its mood.  The fin length on the mantle is another identifier.  Notice the fin on the Illex is about one-third of the mantle length, while on the Loligo, it’s about half the length of its mantle.

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Shortfin and longfin squid

Silver hake is another fish we catch throughout the entire survey, but when trawling offshore, we keep our eyes out for the very similar looking offshore hake.  The slight color difference is what pops out on the sorting belt.  Silver hake reflect a golden color along their dorsal side while offshore hake show more of a bluish hue.  The best way to tell these two apart is to count the gill rakers—the stiff filaments on the gill arch used to filter solids away from the gills.  Silver hake have 16-20 and offshore have 8-11.

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The nearly identical hakes

Christine Kirkun, fishery biologist

Aboard the NOAA Ship Henry B.  Bigelow

2017 Spring Bottom Trawl Survey

Leg I: Fast Prey and Slow Predators

All photos in this post by NOAA/NEFSC Wesley Rand

One of my responsibilities as part of the scientific party on the Bigelow is to open animals’ stomachs to see what they have been preying on. I had a couple of interesting finds today.  I didn’t know these predators were capable of catching what I found in their stomachs!

The first find is something we are seeing pretty regularly, and that is winter skate (below,top two panels) with spotted hake (below lower panel) in their stomachs. If you just look at the two fish, you wouldn’t think skates could catch hake.Notice that the skate’s mouth is on its underside and not in a particularly maneuverable place. Pure speculation, but maybe the hakes rely on hiding in the ocean’s bottom instead of swimming away to avoid predators?  If that were so, skates could easily suck them up when they hiding in the mud or sand.

The second find of the day was something we had not yet seen on this trip; a fat spiny dogfish with a whole Atlantic menhaden in her stomach.


Spiny dogfish female we examined, with a full gut.

The menhaden was about 8 inches long and almost perfectly intact! Atlantic menhaden, commonly known as bunker or pogies, are fast-swimming, schooling fish. Spiny dogfish spend most of the time on the ocean floor and aren’t known to be the fastest swimmers, but I’m sure if one swam into a big bait-ball of menhaden, it could nab one.


Atlantic menhaden, spiny dogfish victim! 

It’s all just conjecture, but that’s one of the great things about being a part of this survey. You get to see things that are happening in the wild, like predator/prey relationships that challenge your view of the world.  When your findings contradict what you thought was possible, you have to think of new ideas to explain how it’s possible. The other half of the fun is bouncing ideas off of colleagues to see if they have any merit or if maybe there’s some part of the picture you’re missing.

Wesley Rand, fishery biologist

Aboard the NOAA Ship Henry B.  Bigelow


2017 Spring Bottom Trawl Survey

Leg I: Southern Fish Make Things Interesting

We’d made it all the way south and had just begun working our way north when bad weather drove us to shelter in Norfolk, VA.  Our work and research primarily revolves around northern fish species so sampling down south affords us the opportunity to briefly dip into the gulf stream and find fish that mostly live to the south of us, but that can also come into northerly waters when currents and temperatures are right.  Sometimes we are familiar enough with a fish to identify it down to its species.  Other times, we may only get down to its family classification.  In any case, when it comes to these southern and/or deep-water fish, we bring them back to the lab where there is more time to closely and carefully key out the species.  The following pictures show the diversity in body shape and color of these beautiful animals.  Enjoy!

Christine Kirkun, fishery biologist

Aboard the NOAA Ship Henry B. Bigelow

All Photos by NOAA NEFSC/Christine Kirkun

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2017 Spring Bottom Trawl Survey

Leg I: Sampling Underway– One Fish at a Time

It’s been more than  a week since we sailed from Newport, RI, sampling is well underway, and we’re still heading south.  If we’re not working up fish, we’re waiting to work up fish.  A question constantly being asked is “what is the net doing” or “where are we”?  In other words, are we fishing, are we steaming (heading for the next sampling station), is a work-up currently happening, or are we sampling for water salinity, temperature and depth or for plankton.  Ultimately, the action begins when the net comes onboard!


The checker filled with mostly dogfish. Photo by NOAA NEFSC/Christine Kircun

The net is pulled out of the water by large winches, and with help from a crane, the contents are dumped into a checker, or a big, metal holding bin.  The little door in the checker allows a scientist to push the fish onto a ladder conveyor belt that brings them onto a sorting belt inside the lab.

Conveyor belts are used at all parts of the sampling process to move catch where it needs to go.  The scientists on watch sort the fish into small, medium or large baskets.  As the baskets are filled and sent to the watch chief, they are entered into the sampling program and sent down another conveyor belt to the three sampling stations.


Sorting squid coming into the wet lab on the conveyor belt. Photo by NOAA NEFSC/ Christine Kircun

There’s where scientists weigh the catch, record lengths and weights, and can take stomachs for food habits studies, remove hard parts like earbones and scales for aging studies, and make observations about fish condition and whether they are ready to spawn. After a basket is worked up, the remains are placed on a lower conveyor belt which leads to a shoot emptying into the ocean.

Depending on the area and time of year, we have a rough idea of what we’ll catch, but there are always surprises.  I’m on night watch (midnight to noon), and while the catch has mostly been spiny dogfish, we’ve also caught a blueline tilefish  and a mola.

Blueline tilefish, Caulolatilus microps, are found on mud and rubble bottoms, and is thought to inhabit burrows and may get up to 15 years old.  Their diet is mostly invertebrates that live on the ocean bottom, and the occasional fish.  Blueline tilefish range from around Virginia to southern Florida/Mexico and at depths of 30-130m.


Blueline tilefish. Photo by NOAA NEFSC/Christine Kircun

The mola (sunfish) we caught was a  Mola mola, one of the world’s three species of mola. It is the heaviest known bony fish, and can weigh in at up to 5000 pounds.  They can be up to 14 feet long and 10 feet wide.  This fish swims in the uppermost waters of the ocean and is often found swimming lethargically and relaxing at the surface; sometimes laying on their side to let birds and small fish eat the many parasites off their skin.  Their diet consists mostly of jellyfish but also eat algae and zooplankton.


Dogfish haul. Photo by NOAA NEFSC/Christine Kircun

Sometimes, it’s not just the unique fish we catch that is impressive, but the amount.  Just before breakfast, we brought up a very large deck-tow of spiny and smooth dogfish.  With the help of our survey tech and a deck-hand, it took 8 of us 5 hours to count the entire bag!  We finished just before watch change, which was perfect timing as we were definitely ready to go to bed.

Christine Kircun

NEFSC fishery biologist

Aboard the NOAA Ship Henry B. Bigelow

2017 Spring Bottom Trawl Survey

Leg 1: Wintery Weather Tests Your Bones

Anybody who has worked at sea knows that your efforts are limited to what the elements will allow. On Friday, March 10 we experienced that first hand. We hit a bit of a squall off the coast of North Carolina. The conditions changed very quickly. In just a few hours the waves went from 3-4 feet to 12 footers with even larger swells.


Rough seas on Leg I.  Photo by NOAA NEFSC/Kateryn Thompson-Delgado

Kateryn Thompson-Delgado

Fortunately, the Bigelow is equipped to fish in rough conditions so we continued to plug away at stations. Working on a rocking vessel takes a lot of energy. Your body has to use so many more muscles just to walk around, and even if you are just sitting, it can get very uncomfortable. I felt even worse for the night watch, who needed to sleep while Mother Nature attempted to throw them out of their racks.

Just as the day-watch’s shift was ending, the winds started to turn again. With everyone drained, the day watch turned in for the night. When we woke up, we found the seas had calmed down significantly. The waves were back down to 2-3 feet. What a difference 12 hours can make on the ocean! Compared to yesterday, you can barely feel the Bigelow’s rocking and I think everyone is a lot happier for it.


Sunrise and clams seas. Photo by NOAA NEFSC/Kateryn Thompson-Delgado

Dealing with rough seas is the part of the “price of doing business” when collecting data at sea. We plan for it and are prepared. Like one NOAA Corps officer told us during our initial trip briefing, “We call it the Spring Survey but this is the month of March. It’s still winter. We expect to hit some winter weather.” When log books and back packs start to go flying across the room, it’s good to know you’re in the hands of capable people who are well prepared.


Wesley Rand

NEFSC fishery biologist

Aboard the NOAA Ship Henry B. Bigelow


2017 Spring Bottom Trawl Survey

Leg I: Welcome Aboard

We are underway for the 2017 NEFSC Bottom Trawl Survey aboard the NOAA Ship Henry B. Bigelow, a fisheries survey vessel that is specifically designed for the science we do at sea.

At 209-feet long, that might seem like a big ship, but put 38 people on it and it starts to feel small really fast. We’ll work and live together for the 18 days of Leg I, which covers the southern-most part of our region. When all four legs are completed, we’ll have collected biological and physical data at more than 300 stations on the continental shelf off the Northeast US coast, including some in Canadian waters.


Southbound on the NOAA Ship Bigelow out of Newport RI. Photo by NOAA Fisheries NEFSC/Wesley Rand

Three different workforces run our operations. Officers of the NOAA Corps, a uniformed service of the United States, are responsible for managing and navigating the ship. Professional wage mariners make up the rest of permanent ship’s crew: engineers who perform mechanical maintenance, electronic technicians that deploy our ocean sensors, fishermen that deploy our trawl net, and stewards that prepare meals. The scientific party, which I am part of, is put together by the Ecosystem Survey Branch of the NEFSC. We’re responsible for executing the science plan, collecting and processing the data.

When working as a scientist at sea, you spend most of your waking hours with the same people in your watch schedule, in my case seven other fishery biologists. You work, eat, and spend a lot of time waiting to get to your next sampling station, together. The first few days of a trip are kind of like your first day of school. You meet a lot of new people and try to remember everyone’s names. You really only work closely with your work force, but we all rely on each other because every part is crucial to the survey’s success.

Wesley Rand, Fishery biologist

Aboard the NOAA Ship Henry B. Bigelow

Inside the Wet Lab

Conveyor belts, stainless steel, rushing water, plastic bucket thumps, computer bleeps, bells and dings, red and green  lights, fish, fish and more fish.  These are some of the sights and sounds in the Bigelow Wet Lab.  Appropriately named  “Wet Lab”, a constant water wash streams across the floor to flush debris and slime out the scuppers.  This floating laboratory is the frontline for fish science.  Usual and not so usual species enter the lab from the net to be processed.

Will Duffy studies a spinycheek scorpionfish

Bill Duffy with a spinycheek scorpionfish, one of the more unusual species, to be sampled.  (Photo by Dave Chevrier, NOAA)

As the conveyor belt moves the species into the lab the most interesting location is in the first position.  This is the place where you see every species before it is sorted into the baskets, buckets and pails.  The colors of blue, turquoise, lime green, yellow, coral, and purple are brilliantly displayed under the bright fluorescent lights.  After the sort, the watch chief enters the species into the FSCS 2 program using the Latin scientific name for identification.  The barcodes on each basket, bucket or pail are scanned to uniquely identify the container and then they are weighed and sent down the line for processing at the three sampling locations.

Jakub Kircun places  an angel shark on the electronic measuring board at one of the sampling stations.  (Photo by Dave Chevrier, NOAA)

At each sampling location there are an abundance of tools to assist the cutter and recorder.  Barcode readers are used to scan a container, so that the recorder can confirm the species.  The container is dumped into a hopper and the sampling protocol begins.  Individual species are first placed on an electronic measuring board which sends lengths and weights to the computer.  For smaller species, a different scale is available to send the weight also.  Knives, tweezers, and scissors are the cutters’ surgical instruments to extract samples such as otoliths (fish earbones, used to determine age and growth), determine the sex of the species and examine stomach prey contents.  The computers prompt for each required data component and record the responses.  Tissue samples such as spines, scales, ovaries and whole fish are either frozen of put into jars with preservative chemicals.

After the survey, the data and samples return to the on-shore laboratory in Woods Hole where the analysis begins…

Heidi Marotta
Aboard the Henry B. Bigelow