Setting Out from Cordova

by David Barbee from the Northwest Explorer

Leg 4 is underway, focusing on an area to the south and east of Kodiak Island. Scientists joining us on this leg include Ann Robertson, Jason Waite, Ashley Hovis, and returning for another leg are Ayla Doubleday, Shari Mullen, and David Barbee. A raft of sea otters bid us farewell from Cordova where the Northwest Explorer put in for our leg change. We are in good spirits with good weather and are gathering high-quality data. On this leg, we’re conducting three surface trawls and one mid-water trawl per day, paired with oceanography and plankton sampling at fixed stations.

Left to right: A raft of sea otters hangs out near the Alaska Marine Highway System ferry dock in Cordova. (Photo credit Ray Haddon). Ann Robertson and Jason Waite are on board for Leg 4 to help process the trawls, shown here with a catch of capelin and immature Chinook salmon. (Photo credit: Ashley Hovis). The science team poses with a catch of juvenile walleye pollock -- from left to right: Ashley Hovis, David Barbee, Jason Waite, Shari Mullen, Ann Robertson, Avla Doubleday.

Sharks of the North Pacific

by Wyatt Fournier from the Northwest Explorer 

Blue shark

As we continue along our Gulf of Alaska survey, catching a wide variety of fish species, we are reminded that this productive ecosystem can support large marine predators. It’s not surprising that our surface trawl intercepts piscivorous sharks that are out hunting for a nutritious meal. Throughout the summer and fall, we’ve been catching salmon sharks, and during this leg we also caught three blue sharks. The salmon shark has a range around the Pacific Rim and has been observed across the GOA and in the Bering Sea. The blue shark’s distribution (see pic) is circumglobal in temperate and tropical waters, with few observations in Southeast and the central Gulf of Alaska. One of the more recent reports in Alaska comes from Yakutat where a blue shark was caught in a commercial net in 1997, which was a strong El Niño year. After we recorded the length and sex of each shark, we released them alive and well.

Pacific Herring

by Wyatt Fournier from the Northwest Explorer

Here the crew begins to sort through a surface tow that caught 47kg of herring.
The next afternoon, we set a tow slightly later in the day and caught 311kg of herring.
These large aggregations of herring have been observed in the inside passage of
Southeast Alaska during the winter months and may provide a prey base for
humpback whales that do not migrate to Hawaii during the cold season.

This component of the Gulf of Alaska Project focuses on the middle trophic level, specifically three forage fish species: Pacific herring, capelin and sandlance. Throughout the Gulf of Alaska ecosystem, these forage fishes provide the critical link between small invertebrates like euphasiids and copepods and species higher on the food chain, including adult predatory fishes, birds, and marine mammals. One of our project goals is to provide a synoptic view, from the shoreline out to beyond the shelf-break, of the distribution and abundance of forage fishes and linkages to the early life stages of the five groundfish species in this study. Our offshore survey will complement the nearshore surveys that assess habitat characteristics and energy content of forage fishes. Gulf of Alaska project researchers will explore interactions among groundfish and forage fish species and their effects on nutritional condition and prey quality. 

Fewer Fish in the Trawls

from the Northwest Explorer by Wyatt Fournier

We do encounter other epipelagic predators, such as this North Pacific daggertooth.  Although this species has been documented up to 146cm, the larger of the two we caught was only 56.2cm.

The catches in our surface trawls this month have been significantly lower than in the cruises in July in the southeast, and in August in the western Gulf of Alaska. Overall, we’ve seen a decline in the number of Pacific salmon we have been intercepting. Previously, all five species of salmon at all maturity levels represented a majority of our catches. As we enter the fall season, juvenile salmon have moved north from this region and the few adults that remain will be spawning soon. Juvenile and adult coho salmon still occur frequently in our catches, while pink salmon catches have decreased considerably. 

Last night, the aurora borealis danced across the night sky in spectacular shades of green. Many of the science and boat crew had not ever witnessed this Alaskan treat, and we all took it as a sign of a safe trip to come.

Returning to Sea

by Wyatt Fournier from the Northwest Explorer

We departed Juneau on September 3rd on board the Northwest Explorer. Our science crew for this portion of the survey is a diverse group of seasoned researchers, returning scientists, graduate students, and volunteers.

From left to right: Dave McGowan, University of Washington PhD student studying fisheries acoustics; Wyatt Fournier, Chief Scientist and Research Fisheries Biologist for the Ecosystem Monitoring and Assessment Program (NOAA); Jen Nemura, Fisheries Acoustics Researcher for the University of Washington; Mike Neary, Seabird Observer and recent graduate of Le Moyne College in New York; Eric Wisegarver, Fisheries Oceanographer for the Fisheries-Oceanography Coordinated Investigations Program (NOAA); and Shari Mullen, University of Maryland Eastern Shore PhD student in the NOAA Graduate Science Program.

Abundance of Salmonids

by Wyatt Fournier from the Northwest Explorer

Fish samples for this survey are collected using a mid-water rope trawl that has been modified to fish at the surface by stringing buoys along the head rope. This allows us to catch juvenile and larval fish of our focal species that utilize the upper portion of the water column. In the Gulf of Alaska, this also means we catch a lot of Pacific salmon. During this leg, we have caught all five species of Pacific salmon: Chinook, sockeye, coho, chum and pink. The dominant species is the pink salmon, also known as the “humpy” due to its morphology during maturation. This short-lived species has been forecasted to be abundant this year, partially due to successful hatcheries in Prince William Sound.

Today we were reminded why the Gulf of Alaska has such an abundance of salmonids, as our trawl intercepted a school of adult coho salmon with stomachs that were bursting with prey. Note the size of the removed stomach relative to the body length of the adult Coho (left pic). After dissecting the stomachs, the prey items were identified as capelin, an energy-rich forage fish. Our very next tow caught a large school of capelin (right pic) from which we sampled individuals that will be brought back to the laboratory for caloric content analysis.

First Catch of Juvenile Cod and Pollock

by Wyatt Fournier from the Northwest Explorer

Juvenile Pacific cod and pollock.

We have finished our first, and northernmost transect of the western Gulf of Alaska grid at a station in Granite Pass. This scenic near-shore station is tucked away between Granite Island and Fire Cove. It is in just 50 meters of water in the head of Harris Bay, about 30 miles southwest from Seward. Besides providing some excellent after hours halibut fishing, this station marks our first catch of juvenile Pacific cod and walleye pollock in 2011. Although we expected to catch juveniles of these species farther offshore, it’s as Captain Ray says “You don’t know, until you tow.” 

Heading out on Second Leg of Western Gulf Summer Survey

by Wyatt Fournier from the Northwest Explorer

Pacific pomfret, a new species to our 2011 survey.

We are now sampling in front of Stevenson Entrance, the body of water that separates Afognak Island from the Kenai Peninsula. This area is notorious for heavy weather as the winds and water push out of Cook Inlet and into the Gulf of Alaska. These last few days have not been an exception to the rule, as we have been pummeled by 30 mph winds and 25 foot seas, forcing us to abandon some oceanography sampling that we will return for at the end of the leg. Continuing down the transect, we crossed over the biologically productive Portlock Bank. Here, to no surprise, our net was full of Pacific salmon of all species and age classes. At the end of our transect, we began sampling deeper waters and encountered a species that was new to our 2011 survey, the Pacific pomfret. This species has a native range throughout the Gulf of Alaska and across the Pacific Ocean to Japan, with documented catches in this area during the summer months. These individuals averaged ~370mm in length and ~900g in mass. 

Juvenile Rockfish Difficult to Identify

by Wyatt Fournier from the Northwest Explorer 

Juvenile rockfish.

After the Northwest Explorer departed from Juneau and began traveling towards the western study sites, we stopped to sample two transects outside of Yakutat and Kayak Island that represent the central Gulf of Alaska. The outer station, offshore from Yakutat at a depth of 200m, proved to be worth the stop as we caught juvenile rockfish in our trawl. These rockfish, of the Sebastes genus, are very difficult to identify during their early life stage and will require genetic analysis in the laboratory to determine the species. Our hope is that they will prove to be Pacific ocean perch, which is one of our focal species for this study and an important commercial fish in Alaska. 

Surviving the Gauntlet

by Wyatt Fournier from the Northwest Explorer 

The Second Leg of the 2011 Summer Survey in the Western Gulf of Alaska has begun! Once again, researchers and students from Alaska and Washington State are onboard the F/V Northwest Explorer conducting surface trawls with concurrent oceanography and acoustic profiling. Our science crew consists of lead acoustician Jennifer Nemura (University of Washington), lead oceanographer Ayla Doubbleday (University of Alaska, Fairbanks graduate student), Brendan Coffin, Michael Kohan (both University of Alaska, Juneau graduate students), seabird / marine mammal observer Jackelyn Slawson (US Fish and Wildlife), and Chief Scientist Wyatt Fournier from NOAA’s Alaska Fisheries Science Center, TSMRI, in Juneau, Alaska. 

Our research goal is to identify and quantify major ecosystem processes that regulate recruitment strength of key groundfish species in the Gulf of Alaska that are commercially and ecologically important. We’re studying five key species in particular: arrowtooth flounder (Atheresthes stomias), Pacific cod (Gadus macrocephalus), Pacific ocean perch (Sebastes alutus), sablefish (Anoplopoma fimbria), and walleye pollock (Theragra chalcogramma). 

Recruitment and survival of these species depends on a biophysical gauntlet that occurs as they switch from an early life history offshore pelagic phase to a nearshore settlement phase. To investigate the mechanisms affecting recruitment and survival, we will contrast two regions: the western Gulf of Alaska with a broad shelf dominated by high oceanographic variability and large demersal fish biomass, and the eastern Gulf of Alaska with a narrower shelf, lower demersal biomass, and higher species diversity.

The first leg of our survey in July covered the eastern Gulf grid, and our survey this month will cover the western Gulf grid.

Rafts of Albatrosses

by Veronica Padula from the Northwest Explorer 

Black-footed albatross.

I boarded the F/V Northwest Explorer on July 8th to relieve Leslie Slater, and have experienced beautiful weather and have observed numerous seabirds ever since. Rafts of black-footed albatrosses and northern fulmars float on the water behind the ship at each samplingstation, ever hopeful to pluck a tasty treat from the trawl we use to sample fish. I have never seen so many albatrosses in one place, sometimes 50 birds at once. We observe seabirds and marine mammals as the ship travels along transects, from one sampling station tothe next by counting the birds that fly or swim across the ship’s path. Large birds, such as northern fulmars, black-footed albatrosses, and glaucous-winged gulls, soar through the sky as we travel, with jaegers and shearwaters making occasional appearances. Smaller birds, such as fork-tailed and Leach’s storm petrels, flit above the waves. I occasionally spot tufted puffins, common murres, marbled murrelets, and rhinoceros and least auklets navigating the waves, diving as the ship approaches them. Appearances by sperm whales, humpback whales, and porpoises have also made this trip special. I am very lucky to be on such an adventure! 

Thresher Shark!

by David McGowan from the Northwest Explorer 

Thresher shark.

Today, we experienced quite a surprise in the last surface trawl of the day – a 15-ft thresher shark (Alopias vulpinus). This large male specimen encountered in our haul shatters the published record, and is most likely the furthest north this species has ever been encountered in the eastern Pacific. This pelagic species is globally distributed and frequently encountered in pelagic fisheries, yet is an extremely rare occurrence in northeastern Pacific waters. In fact, the northern-most extent of the thresher shark’s range is British Columbia, Canada according to published accounts. An anecdotal account reported a thresher shark landed in Sitka, Alaska, in1990, but did not specify where it was captured. Fortunately, our record-holder is still swimming the seas, as he was safely released alive in good condition.

Record Salmon Return

by Jamal Moss from the Northwest Explorer 

Dr. Jamal Moss holding a pink salmon. Photo by David McGowan.

We haven’t encountered many of our target species thus far, which may be due to distribution further offshore this year. In order to rule out this possibility, we will be sampling additional locations offshore of the survey grid once the southeast grid is complete. However, salmon are very abundant, and we are capturing both juveniles and adults at almost every station. Alaska Department of Fish and Game biologists are expecting the fifth largest recorded salmon return this year, and from the looks of it out here, the forecast is probably right. 

Midwater Trawls

by Jamal Moss from the Northwest Explorer 

This morning we performed a mid-water trawl immediately after the first surface trawl of the day. Our goal was to sample a layer of acoustic targets at 200m. We have observed this layer consistently in the deeper portions of the survey. The included echogram shows 10 miles of our transect as the shelf drops off into the abyss. The ship’s acoustic sensors transmit sound energy and receive reflected energy from targets with a density difference from water. We sample what we see on our screen to find out what species compose the target. Several small targets close together could look like a larger target, so we measure what we catch in the net to give us an idea of how many targets we could be looking at on the sounder. We caught lanternfish (myctophids) of about 5cm and not much else in this tow.

Spring Bloom

by Jamal Moss from the Northwest Explorer 

Mt. Edgecumbe appears above the clouds.

Fair weather and calm seas today… Majestic Mt. Edgecombe peeked through the clouds at us as we stepped out on deck this morning. A handful of us stayed up late last night watching Gladiator, and as a result we’ve had lots of commentary on sampling stations with “strength and honor” along with numerous other Russell Crowe one-liners from the movie this morning. 

David Barbee with rockfish.

The spring phytoplankton bloom was late off southeast this year, and Kerri was just explaining that low light levels and/or a deep mixed surface layer (water column stratification) are to blame. Stormy weather will mix the ocean surface, whereas calm weather will allow less dense warmer water to remain undisturbed at the surface, creating stratification. Stratification allows phytoplankton cells to remain in the photic zone where they can utilize both nutrients and sunlight to grow. Currently (post spring bloom) we are observing lots of small flagellated phytoplankton cells in the water column. Their small size and a large surface area to volume ratio allow them to grow well post-bloom, a time when nutrients are scarcer. Kerri says we need to blog about the fish more… so the next post will be about our fantastic finned friends.

Calm After the Storm

by Jamal Moss from the Northwest Explorer 

David Barbee and our cook Alex playing ukulele behind the wheelhouse.

Sunshine brought smiles today… and eventually tee-shirts and sunglasses. 

Oceanography in Stormy Seas

by Kerri Fredrickson from the Northwest Explorer 

I’m an oceanographer on the first leg of the Gulf of Alaska Project summer cruise on the NW Explorer. I’ve been deploying the CTD to obtain a vertical profile (see illustration) of the water column to show us how physical (light, temperature, salinity) and biological (fluorescence) parameters vary with depth. The near-surface waters of our profile indicate the mixed layer, which is a range of depths where salinity and temperature measurements remain the same. 

During our initial vertical profiles, the mixed layer extended approximately 25 meters from the surface. Below 25 meters, the measurements varied. After the large storm that blew through on July 4th and 5th, we can propose that the large amount of turbulence generated from the storm caused the mixed layer to extend all the way down to 40 meters! It will be interesting to see how the mixed layer responds to the calmer weather we are hoping for.

Fourth of July

by Jamal Moss from the Northwest Explorer

Today we woke up to a pleasant surprise of red (strawberry),white (whipped cream), and blue (blueberry) crepes; masterfully created by Alex our cook. And with rumors of an impromptu fireworks show with expired flares floating around today, it’s shaping up to be a fun 4th of July. However, we have a forecast for heavy weather later this afternoon and everyone is presently focused on getting as many stations knocked out as quickly as possible. Deployment of gear went a lot smoother this morning after working out a few hiccups yesterday.

Setting Sail!

by Jamal Moss from the Northwest Explorer

We’re off! We threw the lines after conducting safety drills this morning and began our 20-hour steam south to our first sampling station, which is located just south of Whale Bay off the coast of Baranof Island. Shortly after getting underway, we had a science meeting in the galley where each of us briefed one another on the specifics of their research and sampling goals and how it relates to the integrated research project as a whole. Our scientific crew consists of Dr. John Horne (UW), David Barbee (UW), Leslie Slater (USFWS), Kerrie Fredrickson (WWU), Wyatt Fournier (AFSC) and Jamal Moss (AFSC). John and David are acoustic scientists, Leslie is a seabird expert, Kerri is an oceanographer, and Wyatt and I are research fisheries biologists. After lunch we’ll walk through each sampling activity as a group and assign jobs.

Left: Science meeting in the galley. Right: Kerry demonstrating water sample collection

Acoustic Tests in Young’s Bay

by Jamal Moss from the Northwest Explorer 

This morning we steamed 3 hours south of Juneau to Young’s Bay to test oceanographic gear and perform an acoustic calibration. This quiet bay on Admiralty Island offered the calm waters and water depth we required. The acoustic calibration involved suspending a standard calibration target (38.1 mm diameter tungsten carbide sphere) from monofilament line with downriggers. The downriggers were used to position the target at numerous locations under the boat. Calibration coefficients calculated today will increase the accuracy of relating target strength to fish of a certain species and size class. Acoustics are an important component of this project, and we will blog more about it later in the survey. The second big accomplishment today was the testing of oceanographic gear. Conducting oceanography from a chartered fishing vessel is always tricky business, but fortunately, we had Bill Floering and Eric Wisegarver, 2 oceanographic equipment gurus from the Pacific Marine Environmental Laboratory (PMEL) onboard to help us out. So with their help, the electronics are up and running, the CTD is functioning, and the zooplankton nets were fished without a hitch. As always, we’ll have a few kinks to work out on the first few days of the survey, but so far so good.