Mission: 2023 Summer Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska
Geographic Area of Cruise: Islands of Four Mountains area, to Shumagin Islands area Location (2PM (Alaska Time), June 18): 55o 15.3391′ N, 160o 17.8682′ W
Data from 2PM (Alaska Time), June 18, 2023 Air Temperature: 8.9 oC Water Temperature (mid-hull): 7.7oC Wind Speed: 4 knots Wind Direction: 182 degrees Course Over Ground (COG): 356 degrees Speed Over Ground (SOG): 12 knots
Date: June 19, 2023
Acoustic fisheries surveys seek to estimate the abundance and distribution of fish in a particular area of the ocean. In my case, this Summer Survey is looking at walleye pollock in the Gulf of Alaska. How is this accomplished? Well, it’s not through this method:
The Alaska walleye pollock is widely distributed in the North Pacific Ocean with the largest concentrations in the eastern Bering Sea. For this expedition, Oscar Dyson is traveling to specific regions in the Gulf of Alaska and running transects perpendicular to the bathymetry/contours (which are not always perpendicular to the shore) to take measurements using acoustics and targeted trawling to determine the abundance and distribution of walleye pollock which informs stock assessment and management models. For this blog post, let’s focus on how and why we can use acoustics to locate fish.
Walleye pollock (Gadus chalcogrammus) are distributed broadly in the North Pacific Ocean and eastern and western Bering Sea. In the Gulf of Alaska, pollock are considered as a single stock separate from those in the Bering Sea and Aleutian Islands. Image from Alaska Department of Fish and Game.An snapshot of a nautical chart with transects plotted. The first transect was run during Leg 1 on June 14 at the furthest location to the west, then the ship worked its way back east with approximately 40 nautical miles between transects. Once Oscar Dyson reached the Shumagin Islands, survey work shifted into this area..
Our story starts with the fish itself. Alaska walleye pollock have a swim bladder. The swim bladder is an internal organ filled with gas that allows a fish to maintain its buoyancy and stability at depth.
One interesting effect of the swim bladder is that it also functions as a resonating chamber that can produce and receive sound through sonar technology. This connection was first discovered in the 1970s, when low-frequency sound waves in the ocean come in contact with swim bladders and they resonated much like a tuning fork and return a strong echo (see WHOI’s Listening for Telltale Echoes from Fish).
Internal anatomy of a boney fish. From Wikipedia (CC BY-SA 3.0).
The sound pulses travel down into the water column, illustrated by the white cones here, and bounce back when encountering resistance.(from NOAA Fisheries)
NOAA Fisheries uses echo sounding, which works by emitting vertical pulses of sound (often referred to as pings), and measuring the return strength and recording the time for the signal to leave and then return. Anything having a different density from the surrounding water (in our case – fish, plankton, air bubbles, the seafloor) can return a signal, or “echo”.
The strength or loudness of the echo is affected by how strongly different ocean elements reflect sound and how far away the source of the element is. The seafloor usually makes the strongest echo because it is composed of rock which has a density different than the density of water. In fish, the swim bladder provides a contrast from the water. In addition, each fish species has a unique target strength or amount of sound reflected to the receiver. The size and shape of the swim bladder influence the target strength. There is a different target strength to length relationship for each species of fish – the larger the fish, the greater the strength of the returning echo.
It’s important to note that echo sounders cannot identify fish species, directly or indirectly. The only way we know which fish species is causing a signal is based on trawl catch composition. There is nothing within the acoustic data that lets us identify fish species, even with the catch data. This is a subtle, but important, distinction. Acoustic data, particularly calibrated acoustic data, in tandem with the information from the trawl, definitely allows us to count fish.
Where is the echo sounder on Oscar Dyson? Look at the figure in the next section of this post – it’s a sketch of NOAA Ship Rainier, but the placement of the echo sounder is the same for Dyson. You can see a rectangular “board” that is extended down from the center of the ship. This is called – what else – the center board! Attached to the bottom of the center board are the echo sounders. When lowered, the echo sounders sit at 9 meters below the level of the sea (~4 meters below the bottom hull of the ship).
Did you know… Southern Resident killer whales use their own echolocation clicks to recognize the size and orientation of a Chinook’s swim bladder? Researchers report that the echo structure of the swim bladders from similar length but different species of salmon were different and probably recognizable by foraging killer whales. (reported in Au et al., 2010)
It starts with a calibration
Typical setup of the standard target and weight beneath the echo sounder.(from NOAA Fisheries)
Before we can begin collecting data, we need to calibrate the echo sounder. The calibration involves a standard target (a tungsten carbide sphere) with a known target strength. The calibration needs to be completed in waters that are calm and without significant marine life for the best results.
The sphere is suspended below the ship’s hull using monofilament lines fed through downriggers attached to ship railings. One downrigger is in line with the echo sounder on the starboard side, and the other two on the port side. This creates a triangle that suspends the sphere in the center of the echo sounder’s sound beam. By tightening and loosening the lines, the sphere can be positioned under the center of the sound beam and can also be moved throughout the beam. By doing an equipment calibration at the beginning and end of a survey, we can ensure the accuracy of our data.
One of the port side downriggers
A weight that goes at the bottom of the filament to ensure the calibration sphere remains below the echo sounder
The tungsten carbide sphere attached to the line, being lowered over the side
Location Data
Latitude: 60°55’68” N
Longitude: 179°34’49” E
Ship speed: 11 knots (12.7 mph)
Weather Data from the Bridge
Wind Speed: 10 knots (11.5 mph)
Wind Direction: 300°
Wave Height: 2-4 ft with a 4-6 ft swell
Surface Water Temperature: 8.7°C (47.6°F)
Air Temperature: 8°C (46.4°F)
Barometric Pressure: 1013 millibars (1 atm)
Science and Technology Log
Previously, we learned how the biological trawl data onboard the NOAA Research Vessel Oscar Dyson are collected and analyzed to help calculate biomass of the entire Bering Sea Walleye pollock population. Last blog, I mentioned that the scientific method for estimating the total pollock biomass is not complete without acoustics data, more specifically hydroacoustics! In fact, hydroacoustic data are the real key to estimating how many pollock are in the Bering Sea! That is why our mission is called the Alaskan Pollock Midwater ACOUSTIC-trawl Survey.
Screenshot showing our transects on leg 3 of the pollock midwater acoustic survey. Fish icons indicate where we validated acoustic data with biological sampling. Hydroacoustic data were collected continuously along north/south transects.
The Oscar Dyson is using hydroacoustics to collect data on the schools of fish in the water below us, but we do not know the composition of those schools. Hydroacoustics give us a proxy for the quantity of fish, but we need a closer look. The trawl data provide a sample from each aggregation of schools and allow the NOAA scientists that closer look. The trawl data explain the composition of each school by age, gender and species distribution. Basically, the trawl data verifies and validates the hydroacoustic data. The hydroacoustics data collected over the entire Bering Sea in systematic transects combined with the validating biological data from the numerous individual trawls give scientists a very good estimate for the entire Walleye pollock population in the Bering Sea.
So what is hydroacoustics and how does it work???
Hydroacoustics (“hydro” = water, “acoustics” = sound) is the field of study that deals with underwater sound. Remember, sound is a form of energy that travels in pressure waves. Sound travels roughly 4.3 times faster in water than in air (depending on temperature and salinity of the water). Here is a link with an interactive animation comparing the speed of sound in water, air, and steel! This change in speed will become very important later… keep reading!
Lower sound frequencies travel farther. This is how humpback whales can communicate over great distances with their whale songs! Click on whale songs to hear one!
Whales are not the only aquatic organisms to use sound! Much like dolphins use sound to echo-locate, people use technology to “see” under water using sound energy. We call this technology SONAR (Sound Navigation And Ranging).
An animation of dolphin echo-location (courtesy of Discovery of Sound in the Sea).
On a typical recreational watercraft, this technology can be found in the form of a “fish-finder.”
Recreational “fish-finders” can be found on many personal watercraft (courtesy of Discovery of Sound in the Sea).
In commercial fishing, this technology is used in much the same way, just on a larger scale. Here is an animation showing a commercial trawler using SONAR to locate fish.
Commercial fishing boat using hydroacoustics to locate fish. This animation illustrates how a fish shows up as an arch on the onboard display (courtesy of Discovery of Sound in the Sea).
The Oscar Dyson has a much more powerful, extremely sensitive, carefully calibrated, scientific version of what many people have on their bass boats. These are mounted on the pod, which is on the bottom of the centerboard, the lowest part of the ship. The Oscar Dyson has an entire suite of SONAR instrumentation including the five SIMRAD EK60 transducers located on the bottom of the centerboard that operate at different Khertz, the SIMRAD ME70 multibeam transducer located on the hull, and a pair of SIMRAD ITI transducers on the trailing edge of the centerboard (one pointed toward the starboard side, the other toward port).
Illustration of the Oscar Dyson showing the hydroacoustic transducers located on the centerboard and the hull of the ship.
This “fish-finder” technology works by emitting a sound wave at a particular frequency and waiting for the sound wave to bounce back (the echo) at the same frequency. The time between sending and receiving the sound wave determines how far away an object is, whether it be the bottom or fish. When the sound waves return from a school of fish, the strength of the returning echo helps determine the fish density (how many fish are there).
An echogram taken from the Oscar Dyson. Shades of yellow and red show extremely large, dense schools of fish. The solid red at the bottom of the picture is the bottom of the sea which is at 94.12 meters at this location.
Another piece of the puzzle… how reflective an individual fish is to sound waves. This is called target strength. Each fish reflects sound energy sent from the transducers, but why? For fish, we rely on the swim bladder, the organ that fish use to stay buoyant in the water column. Since it is filled with air, it reflects sound very well. When the sound energy goes from one medium to another, there is a stronger reflection of that sound energy. The bigger the fish, the bigger the swim bladder; the bigger the swim bladder, the more sound is reflected and received by the transducer. We call this backscatter, or target strength, and use it to estimate the size of the fish we are detecting. This is why fish that have air-filled swim bladders show up nicely on hydroacoustic data while fish that lack swim bladders (like sharks), or that have oil or wax filled swim bladders (like Orange Roughy) have weak signals.
X-ray of fish showing the presence of a swim bladder (courtesy of DeAnza College).
Target strength is how we determine how dense the fish are in a particular school. Scientists take the backscatter that we measure from the transducers and divide that by the target strength for an individual and that gives you the number of individuals that must be there to produce that amount of backscatter. 100 fish produce 100x more echo than a single fish. We extrapolate this information to all the area of the Bering Sea to estimate the pollock population.
A close look at part of Transect 27. In this echogram, the area backscatter numerical values are included. At the top of the water column, you can see what are probably jellyfish which have little backscatter since they have no swim bladders. Along the bottom are groundfish. In the center of the water column are several large schools of Walleye pollock with strong backscatter. The square that has a value of 2403.54 shows several large schools!
So the goal is to measure the hydroacoustic density along each transect and extrapolate that data to represent the entire survey area between transects (the area not sampled because the Oscar Dyson can’t cover every square meter of the Bering Sea). When you combine the hydroacoustic data for all of the 30 transects (a total of ~5,000 nautical miles in an area of 100,000 square nautical miles) and the lengths collected in the biological trawl data, you can convert the length data into target strength data to create a distribution of target strengths and find the average target strength for the population. In doing so, you get a complete picture of the Walleye pollock population in the Bering Sea.
The BIG picture. This is the combination of hydroacoustic data and biological trawl data analyzed to show what the entire walleye pollock population looked like for 2009 (courtesy of the Alaska Fisheries Science Center www.afsc.noaa.gov/Publications/ProcRpt/PR2010-03.pdf). Analysis is still being done on the current survey. This year’s results will be out in a report this fall. Expect some changes!
But there’s more!!! Scientists ALSO use hydroacoustic data when trawling to determine if they have caught a large enough sample size to collect fish length data to validate their target strength data. If you recall reading my first blog from sea that taught about the parts of the net, I wrote about and had a drawing of the “kite” on which the “turtle” was attached. The “turtle” is a SIMRAD FS70 trawl SONAR. It has a downward facing transponder that shows a digital “picture” of the size of the net opening. You can also see individual fish and/or schools of fish enter the net by watching this display. Since the scientists only need about 300 fish for a statistically significant sample, they watch this screen carefully so that they do not take more fish than they need. When the lead scientist thinks there are enough fish in the net, she gives the request to the Officer on Deck to “haul back.” Unlike commercial trawlers, a typical trawl on the Oscar Dyson only lasts 25 minutes. Sometimes, we are only officially fishing for 5 minutes if we pull through a large school.
What are the data telling us?
The Walleye pollock data suggest that the population is currently stable; however, there is some evidence of pollock in waters that have traditionally been north of their uppermost documented population range. Are warmer waters due to climate change to blame for this possible shift? Here is an interesting article that addresses this issue and raises several other trends regarding pollock population response to changes in food source and predation due to climate change. Click on the picture to open the article!
How might climate change affect fish sticks? Click on the picture to read more!
The economic and ecological implications of a shifting pollock population range are a bit unsettling. Fish do not know political boundaries. As the pollock population range possibly shifts north, more of that range will lie within Russian waters than in previous years. This may hurt the U.S. commercial fishing industry as they settle for less of a resource that was once abundant. Since quotas are set based on last year’s numbers, there is a time lag which may result in overfishing in U.S. waters that might lead to a collapse in the Alaskan Walleye pollock fishing industry. The U.S. has invested a tremendous amount of research into maintaining a sustainable pollock fishery. Other countries may be responding to a variety of factors in which sustainability is just one when they are managing pollock stocks and setting catch quotas. Since pollock is a trans-boundary stock, this could lead to greater uncertainty in management of the entire population if pollock increasingly colonize more northern Bering Sea waters as influenced by climate change.
Food for thought…
Next blog, we will learn about cutting edge technology that may eventually make hauling back fish and collecting biological fish data on board the acoustic survey missions obsolete.
Personal Log
It’s tomorrow, TODAY! This morning at 6am Alaska Time, we crossed the International Date Line (IDL). The IDL is at 180° longitude. General Vessel Assistant Brian Kibler and I went out to the bow of the ship so we would be the first onboard to cross the line!
Map of the Bering Sea showing both the International Date Line and the 180th longitude. Our closest point to Russia was 12 nautical miles from Cape Navarin which is very close to 180 longitude.
Over the next two days, our transects take us back and forth over the IDL 3 more times. Fortunately, onboard our Oscar Dyson time warp machine we simply observe the Alaska Time Zone (the time zone from our port of call). With everyone onboard operating different shifts, and with 24/7 operations, it would be quite confusing if we kept changing our clocks to observe the local time zone.
The Order of the Golden Dragon!
Mariners who cross the IDL when at sea are inducted into the “Order of the Golden Dragon” and receive a certificate with the details of this momentous crossing. There are several other notorious crossing that receive special recognition. They are:
▪ The Order of the Blue Nose for sailors who have crossed the Arctic Circle.
▪ The Order of the Red Nose for sailors who have crossed the Antarctic Circle.
▪ The Order of the Ditch for sailors who have passed through the Panama Canal.
▪ The Order of the Rock for sailors who have transited the Strait of Gibraltar.
▪ The Safari to Suez for sailors who have passed through the Suez Canal.
▪ The Order of the Shellback for sailors who have crossed the Equator.
▪ The Golden Shellback for sailors who have crossed the point where the Equator crosses the International Date Line.
▪ The Emerald Shellback or Royal Diamond Shellback for sailors who cross at 0 degrees off the coast of West Africa (where the Equator crosses the Prime Meridian)
▪ The Realm of the Czars for sailors who crossed into the Black Sea.
▪ The Order of Magellan for sailors who circumnavigated the earth.
▪ The Order of the Lakes for sailors who have sailed on all five Great Lakes.
NOAA Teacher at Sea: Margaret Stephens
NOAA Ship: Pisces Mission: Fisheries, bathymetric data collection for habitat mapping Geographical Area of Cruise: SE United States continental shelf waters from Cape Hatteras, NC to St. Lucie Inlet, FL Dates: May 22-24, 2011
Weather Data from the Bridge as of 12:43 May 24, 2011
Wind Speed 9.67 knots
Wind Direction 147.00 º
Surface Water Temperature25.09 ºC
Air Temperature 24.20 ºC
Relative Humidity 83.00 %
Barometric Pressure 1016.30 mb
Water Depth 20.57 m
Skies: Clear
The scientists’ work day never ends. Their scheduled twelve hour shifts routinely extend to fourteen, even eighteen hours, because they keep going until their tasks are completed, no matter how long they take. By night, beginning at 6 p.m., the acoustics team uses multibeam and split beam sonar to conduct mapping work needed to determine a course for the fish surveys the next day. Based on previous findings and the goals stated by Chief Scientist Nate Bacheler, the team sets up a mapping area and communicates it by ship’s radio to the bridge. The ship runs transect lines (similar to large grid lines, in a back and forth pattern) throughout the hours of darkness to gather information about the contours of the sea floor and translate it into three dimensional images to help visualize potential locations for setting fish traps.
Transect lines used for mapping sea floor.
Transect lines used for mapping sea floor.
Here’s where the “art” of science comes in. Because there are so many variables, Nate has to weigh what is known from previous surveys with the recent catches and video footage from the underwater cameras, the new data gathered, factor in wind and current conditions, distance between sites, and any other priorities, and use his best judgment to map a trapping route for the day that looks most promising to catch the target fish species. The entire operation is a delicate balance between science and art.
The videography team backs up all the footage recorded by the underwater cameras attached to the fish traps during the day. Christina spends four to six hours for each set of six traps to catalog and back up the video footage. Nate and Christina view some of the film immediately to look for signs of fish that may not have been trapped and clues to the type of bottom habitat.
Fish Survey
Fisheries scientists face an interesting challenge: their subjects of study—fish, of course—are mostly out of sight, underwater, mobile, often evasive, in scattered groupings, and sometimes smart or timid enough to avoid the enticement of baited traps. Yet to assess the health of fish populations and contribute information leading to sound stock management policies, scientists must first find the fish and then attempt to estimate their relative numbers from year to year. Sandy areas on the sea floor rarely harbor many fish of interest to this survey. Hardbottom provides a much more desirable habitat for fish to feed.
Historically, quantifying fish stocks has involved two principal methods:
Fishery dependent sampling – In this method, samples from commercial fish catches are used to estimate the population size of the species of interest. Because fishery dependent sampling relies on fish already caught by commercial fishers, it has the advantage of not requiring a large, expensive infrastructure of research ships and full
scientific teams. However, the data collected are affected by how fishers harvest their catch, including the areas fished, changing priorities of the market (i.e. if the market price for a particular species is up or down, the fishers are likely to go for more or fewer of them, accordingly), type of equipment used (nets, lines, traps, etc.), the experience and expertise of the fishermen, and seasonal or year-to-year changes in availability of the fish.
In fishery independent sampling, the method used on Pisces and other NOAA fish survey vessels, scientists use existing knowledge of species’ habitats along with statistical techniques to select areas to collect fish with traps, nets and other devices. The advantage is that the scientists can design the sampling area and method carefully, and the data collected are not directly affected by the kind of harvesting done by the fishing industry.
Baited chevron traps ready for deployment
The survey work on Pisces involves positioning a set of six baited fish traps, known as chevron traps because of their shape, on the sea floor in an effort to capture red snapper and grouper for population assessment. The science team begins preparing the traps at 6 a.m. each day. They spear and cut whole menhaden, a plentiful fish common to the east coast and popular as bait fish, and suspend them from cords inside the traps. They attach two high-definition video cameras to the outside of each trap to capture images of the sea floor and fish communities that might not enter the traps, tag each trap with an identification number, and attach brightly colored buoys that float on the surface to mark the trap locations for easy spotting and to warn passing boats to avoid them.
The deck crew, directed by the Chief Scientist, releases each trap from the rear deck in the pre-selected position. Because the traps are weighted with heavy metal rods, they fall directly to the bottom and are left there to “soak” for ninety minutes. By the time the last trap in each set of six is in place, it is usually time for the ship to return to the first location to pick up the traps in sequence. The deck crew, guided by the operator of the “pot hauler” (a mechanized hoist and pulley system) sitting above, raises each trap and lifts it to the side deck, careful not to run over the trap lines or damage the cameras.
Then the real work begins. In some cases, the traps come up empty, save for the untouched bait. While a catch of “zero” may be disappointing, the zeroes provide important clues. The empty traps, together with the video images and sea floor mapping work, help the scientists assemble a better picture of the sea floor conditions and fish locations…or at least where they are not.
Crew member Kirk Perry observes as Investigators David Berrane and Dave Meyer empty catch of red snapper and black sea bass from chevron trap
When the traps come up containing live fish, as they often do, the deck is abuzz with activity. The deck crew tips the traps open to slide a mass of jiggling, flopping, somewhat stunned sea life into awaiting large plastic containers. The science team begins sorting the catch by species, tossing each into separate bins. That is easier said than done, because the fish are slimy, slippery, and squirmy, and most have sharp spines. The fish handlers wear special high-grip gloves, waterproof fishing bibs and boots, but all protection that doesn’t prevent them from being decorated with fish scales on their hair and clothes and a decidedly fishy aroma by the end of the day. Water sprays about, and many a fish flops out of the containers and must be retrieved, over, under, or on top of lab tables and equipment. I learned the first day the danger of talking while this commotion was going on – unless one wants a mouthwash of fishy liquid, not too tasty at any time of day.
Non target species are released back into the water immediately. On this trip so far, the haul has included algae, octopus, sea stars, masses of sea jellies, and three moray eels. The sea creatures face some trauma from entrapment and being lifted up from the depths of thirty meters (approximately ninety-eight feet) or more, but the scientists make every effort to release the fish they don’t need for further study as soon as possible.
Many bony fish have swim bladders, balloon-like organs that help them control their position up and down in the water column by regulating buoyancy automatically, so they do not float or sink. The bladders allow gases such as oxygen and carbon dioxide in and out as the fish ascend or descend.
The gases in the swim bladder can over-expand when the fish are brought quickly from the bottom to the surface, as happens when they are reeled in on hooks and lines or captured in traps. When that occurs, the fish look like they are blowing bubble gum, as the pressure from the expanded swim bladders can push internal, sac-like tissue through their open mouths temporarily.
A team member places each container on a digital scale and calls out the weights loud enough for the data recorder to hear above the din of the equipment in the background. The team sets up in assembly line fashion to measure and record length of each fish. One or two people line up the still-lively fish while two stand at measuring boards, hold the fish flat to measure snout to tail, and then release them through a chute back into their ocean habitat. Only the individuals needed for further study are kept, frozen for later processing.
Measuring black sea bass in the wet lab
The NOAA team arranged to donate the fish catch to a local food bank program based in Jacksonville, part of the national Second Harvest initiative to assist families in need. The crew has gladly pitched in even after their long regular work shifts to fillet and package the fresh fish for donation. Since the market price for fillets of these species is $10 or more per pound, this represents a significant contribution of high-quality, protein-rich fresh fish.
Personal Log
After a few days working with the fish survey team, I began doing overnight shifts with the acoustics group. Much of their work is highly technical, requiring knowledge of fish habitats, geology, mapping, elements of ship’s navigation, Geographic Information Systems (GIS), sonar technology, and computer-based data management.
To the uninitiated (that would be me) the multiple computer screens displaying sonar, navigational information and models of the sea floor are overwhelming. Had I not been instructed otherwise, I might think I was in a high-tech hospital room, as the multibeam sonar projects an image akin to a medical ultrasound.
The acoustics team members, headed by Investigators Warren Mitchell and Todd Kellison, were unfailingly patient as they explained to me how all the elements of their complex system fit together and what I was to do.
My first assigned task was to mark points visible on the sonar screens representing changes in topography – ledges, mounds, and other contours that might be good potential habitat for our target species, red snapper and grouper. After the data are entered and processed, they are used to construct three dimensional images of the sea floor.
Challenge at Sea: Fatigue
Besides learning the basics needed to assist the team, a big challenge is staying awake and alert enough throughout the night to avoid making any costly errors. The other members of the team are better adjusted than I to sleeping during the day, although with all the work they do, they don’t get much rest. Try as I might, I haven’t managed to stay asleep for more than three or four hour stretches once the sun comes up, even after a couple of all-nighters and with the shades in the cabin fully drawn. I hate to miss all the activity on board, anyway, and I can catch up on sleep after returning to land.
Who said scientists don’t have fun? Although the acoustics work is mentally taxing, there is allowance for humorous banter and frequent foraging trips for midnight snacks. Warren labeled those mini-meals “re-dinners” and coined the verb form, “re-dinnering”. We each forage through the cupboards and refrigerators in the mess to assemble creative combinations. Among the highlights: English muffins with Nutella, monster salad with grouper and salmon, with and without wasabi, fruit and cake with ice cream, corn chowder and fresh baked bread. Somewhere between 2 and 4 a.m., it is usually time for a pre-breakfast bowl of cereal and a third or fourth cup of coffee for the night owls …. the ones who don’t have trouble sleeping during daylight hours!
Along with the eating and constant work, there are interludes for stretches, yoga and chin-ups from the well-placed overhead bars to keep oxygen flowing to our brains. I can certainly sympathize with people who work shifts, especially overnight, for long periods of time.
Fishy Humor?
Another custom on these research trips is to note any significant sayings or funny phrases that trip from anyone’s lips during the long days and nights.
Among the recent entries:
When the traps come up with no fish: “Zero is a number, too!”
When very few fish, or ones other than our subjects of study, are trapped: “Some is better than none.”
After the umpteenth trap haul containing nothing but black sea bass: “Black sea bass are fish, too.”
Every time someone expresses optimism about bringing in a big haul: “This is the one.”
To refer to just about anything that goes wrong: “It could be worse.”
Attention!
A few times each day, the officer on deck announces something of note over the ship’s public address system.
“Safety first!” Chief Engineer Garet Urban with First Engineer Brent Jones
“Attention Pisces: Sea turtles off port bow…: I rushed out to the deck just in time to catch a glimpse of two turtles.
“Attention Pisces: “Fish call. Fish call on rear deck.” When we are in a quiet period between operations or in transit to one research location to another, anyone who wishes to can use a rod and reel off the rear deck. Many of the crew members enjoy this pastime. So far, I haven’t seen any big catches.
I’m still waiting for the “Abandon Ship” drill. My required hat, long sleeved shirt and survival suit are ready to go as soon as the alarm sounds. I hope it is not during the few hours when I’m fast asleep!
Engineering Tour
I asked the Operations Officer, Lieutenant Tracy Hamburger, if it would be possible to have a tour of the ship’s engine room and other mechanical operations. Before I knew it, First Engineer Brent Jones appeared to lead me on a tour of the very impressive essential inner workings of Pisces. The ship’s engineering department keeps Pisces nearly self-contained with all the systems that support its safe operations, the science work, and the lives and comfort of the people aboard. The engineers maintain and repair everything, including the four engines, the fresh water supply system, refrigeration and air conditioning, trash incineration, sewage treatment and disposal, and all the lifts, hoists and other equipment used for scientific and other work.
Crew member Ryan Harris trying his luck during evening fish call
Brent informed me that the ship’s trash is combusted at temperatures of 1200 degrees Fahrenheit or higher. Those high temperatures ensure a fairly complete combustion; nevertheless, there is a residue, or sludge, that must be cleared out regularly. The only materials prohibited from being placed in the incinerators are batteries and aerosol cans, which can explode at those temperatures and damage the system. Any hazardous materials such as paints, solvents, and other chemicals must be labeled and stored for disposal at specialized facilities once the ship returns to port.
Among the impressive other Pisces features and facts:
The ship, with a full complement of crew and scientists, generates about 1400 pounds of waste per day.
Special “quiet” controls make her four engines among the quietest in the NOAA fleet.
360 degree thrusters provide force enough to make Pisces very maneuverable in all directions.
1900 gallons or more of marine diesel fuel are consumed each day under normal operations.
Special Terminology
Fishery – In a resource management context, a fishery refers to a particular species of interest. For this Pisces research trip, the red snapper and grouper fisheries are of most interest.
Fisheries biologists – Scientists who study anatomy and physiology, life cycles, population dynamics, behavioral aspects, habitats, distribution and abundance of fish. They may be employed in academic research, government, education, or commercial sectors.
Menhaden – A bait fish commonly used for fisheries research. Menhaden are members of the clupeid family, which includes sardines and herrings. They are used here because they are abundant, relatively cheap, easy to catch and transport, the right size for the trap array and attractive to the target species in the snapper-grouper complex.
Hardbottom habitat – a sea floor type that allows for attachment of sponges, seaweed, and coral, which in turn support a diverse reef fish community. The target snapper-grouper complex fish species prefer hardbottom conditions, which are also known as “live bottom” or “live rock”.
Links & Resources
Pisces –ship tracker– Yes, we may be going around in circles or loops …doing survey work.
Weather from the Bridge: Time:05:56 am Latitude:61.05 N Longitude:178.51 W Wind Direction: 300 N Wind Speed:12.5 knots Sea Temperature:8.0 C (46.4 F) Air Temperature:9.5 C (49.10 F) Barometric Pressure:1008 mb Foggy skies
Foggy Skies
SCIENCE & TECHNOLOGY LOG:
Wednesday, July 28: after a cloudy and foggy day, (Picture of a ship on Russian waters)the weather finally changed and the afternoon became sunny and clear, very pleasant to be on deck. For the past several days we have been navigating in the Russian territorial waters of the Bering Sea, for which we have permission, as testified by a letter in Russian posted on the bridge. Alaska used to be a possession of Russia, until October 18, 1867 it became a territory of the United States.
We can still see Russian Orthodox churches still open today in some islands of Alaska. Pretty soon the direction of the current transect or line course, will bring us as close as 12.6 miles from land. At one point we were close to 14 miles off Cape Navarin, but there was fog in the distance and without notice the beautiful afternoon disappeared and I was not able to see Russia. Later on during the afternoon trawl, while sorting the catch of Pollock, a big fish came out on the conveyor:it was a Chum Salmon or Dog fish” said Dr. Mikhail Stepanenko, a Russian scientists working with his colleague Elena Gritsay, from the Vladivostok School of Fisheries, collaborating in the Walleye Pollock survey to help improve the management of Russian fisheries. According to Mikhail it was most likely that the chum salmon had been born in Japanese waters, and had migrated to spawn near Cape Navarin.
Chum Salmon
After I measured it then I dissected the fish to see if it was male or female. The organs were slightly different in size and location than the Pollock, but basically the same. The pillora seca was very large, engulfing the long stomach and liver, and the kidneys were right behind the swim bladder. The presence of an organ called gonads or testes confirmed that it was a male. I tried to locate the otolith, for my classroom collection bu could not locate it. There was also a very interesting fish in the catch: a Toad Lump sucker, a very cute looking fish that resembled a blow fish because it was swollen like a balloon. It had a suction orifice in the underbelly too.
PERSONAL LOG:
I noticed that in this cruise there is an atmosphere of professional collaboration between scientists and the crew. There is also a sense of collegiate amongst all the scientists working on board the Oscar Dyson. The Pollock Survey is the primary mission, but there are other parallel missions going on: the seabird survey, done by Marty and Liz, and the marine mammal survey, done by Patty, Paula, and Ernesto. To do research on the Bering Sea is very challenging due to the remote locations, and the storms, winds, large waves, and extreme weather. The need for oceangoing vessels to work in these extreme conditions makes it very expensive, so when ships like the Oscar Dyson are deployed, different missions are planned to “piggyback” along. I was very impressed by the international collaboration in the mission, with the two Russian scientists on board conducting research on the Pollock fisheries, since part of the transects done by the Oscar Dyson covered Russian territorial waters as well. The fact the one Mexican scientist, a Filipino cook, and a Dominican teacher at sea were part of this cruise added more countries to the mission. Just like us, fish travel in different waters, local and international, and they too are citizens of the world’s oceans. I wanted to commend NOAA’s administration for providing career opportunities to minorities, Latinos, and women to work as scientists, technicians, Corps officers, and crew.
“Una Cooperacion Internacional” Durante todo el trayecto de este crucero de Monitoreo del Pollock he notado un ambiente de profesionalismo entre el personal cientifico y la tripulacion, asi tambien como un ambiente de colegiatura enter los diferentes cientificos trabajando a bordo del Oscar Dyson. La mision primaria es el Monitoreo del Pollock, pero a su vez hay otras misiones paralelas a la mision principal, como son el Estudio de las Aves Marinas,por Liz y Marty, asi como el Estudio de los Mamiferos Marinos, por Patty,Paula, y Ernesto. Hay que entender que hacer investigacion cientifica en el Estrecho de Bering es una tarea logistica complicada por lo remoto del lugar, lo extremo del clima, asi como gigantescas olas. Solo se pueden usar barcos de navegacion oceanica que son muy costosos, por lo que cuando embarcaciones como el Oscar Dyson son lanzadas, multiples misiones son planeadas al mismo tiempo tambien. Me llamo mucho la atencion la cooperacion internacional, especialmente los dos cientificos rusos a bordo, que tambien relizaban estudios del Pollock, lo cual tiene mucho sentido, debido a que gran parte de la investigacion cubria aguas territoriales rusas. El hecho de que un biologo Mexicano, un filipino (Ray el cocinero), y un Maestro en el Mar dominicano tambien forman parte de este crucero le agregan mas paises a la mision. Yo quiero felicitar a la administracion de NOAA por proveer oportunidades de carreras profesionales tanto a minorias, como a Latinos, y a mujeres para trabajar como cientificos, tecnicos, Cuerpo de Oficiales o como tripulantes. Yo creo que esto es un gran incentivo para que mas jovenes estudiantes de escuela intermedia y secundaria puedan perseguir carreras profesioanles en Conservacion Ambiental.
