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Alaska News

Teams of Southeast Alaska divers count herring, urchins, geoducks to manage fisheries

  • Author: Scott Walker
  • Updated: May 31, 2016
  • Published April 16, 2014

Alaska has some of the most successful commercial fisheries on the planet. One of the reasons that Alaska has been so successful with resource management is its requirement and reliance on some of the best research in the world. Alaska animals are counted by air, foot, snowmobile, boat and my favorite, scuba gear.

Underwater research is conducted throughout the state, and one of the biggest programs is in Southeast Alaska. The Southeast dive team consists of 24 divers, a mix of commercial fisheries area management biologists, assistant area biologists, herring and shellfish research biologists, and a few biologists from other divisions. Each year the dive program coordinator sends out a list of planned dive trips for the season and everyone signs up. Starting in March, the state research vessel Kestrel travels to each research area with a different set of divers to conduct the preplanned dive transects. Each year, all of the major herring stocks in Southeast Alaska are surveyed, and 10 or so trips for shellfish assessment are conducted throughout the summer. An average trip lasts seven to 10 days.

Diving in Southeast Alaska can be spectacular in many research locations. Southeast Alaska hosts large numbers of colorful invertebrates, diverse kelp types and numerous species and concentrations of fish. There is always something to see on each dive and you never know when you'll be surprised by a shark, octopus or sea lion that comes at you from the distant gloom. No diver can avoid a racing heart when a 500-pound sea lion suddenly appears and the visibility is down to 10 feet. I have often felt large movements of water just out of the range of visibility.

Dive fishery assessment in Southeast Alaska began in the 1970s when a small group of department biologists began conducting underwater dive transects to estimate the number of herring eggs that were laid down by spawning herring and to document the presence of various type of shellfish such as urchins, sea cucumbers, abalone and geoduck clams.

Rugged diving conditions

Initial surveys were done on industry boats and department skiffs. Today, there are larger state research vessels. It was an exciting time to be involved in dive research and the program gradually developed into a valuable research tool now used to help commercial fisheries that are a large part of Southeast Alaska's economy.

I was trained to use scuba gear 1987 while attending the University of Alaska in Fairbanks and began diving with the department's research team in 1990. At that time the department used the research vessel Steller, a 60-foot ex-seine boat that was outfitted with an air compressor, dive locker, two skiffs and bunks to house and feed six divers plus two crewmen. Each morning, we would gear up, jump in the skiffs -- three divers to a skiff -- and spend the day conducting transects. These surveys were before GPS, so each skiff would have a map with a dot marking the location of the transect. We would do our best to jump in the water in just the right spot to start the transect. We didn't have dive ladders and pulled ourselves into the small skiffs when we were finished.

The Southeast dive program has developed considerably since those early days. Divers now use a 106-foot specially designed research boat called the R/V Kestrel. It was purchased on auction when the Canadian government decided that they couldn't use it for its intended purpose as a sonar boat. We moved to custom-made "workskiff" brand aluminum dive boats, custom made aluminum ladders for getting in and out of the water, and we have a console mounted GIS mapping units that can pinpoint dive locations to within 3 meters.

Most dives are conducted using two methods -- one for herring, the other for shellfish. Both methods consist of diving a perpendicular transect that begins at the shoreline and ends either when the spawn runs out or when a set depth is reached. Our maximum depth at all times is no more than 90 feet and usually 70 feet. We have used many other types of methods throughout the years on special projects but these two are the most commonly used.

Herring diving

Herring diving for me has always been an endurance test. Herring diving occurs in the spring when the water is cold and diving protocol requires slow movement through the water. Travel from big boat to the dive sites is done in an open skiff, and cold spring winds can penetrate your dive suit before you begin your dive. A cooler with hot water is put into the back of the skiff each morning so that you can at least warm up your hood and gloves before you put them on.

If you want to be a herring diver, you initially start in the program as the second diver for two to three years before becoming "calibrated." Once calibrated, you can "estimate" herring eggs. The process to get calibrated is to count herring egg samples during the yearly calibration times. During these times, a sample of herring eggs is taken from a good beach, all the divers estimate the eggs, and then the eggs are counted in the lab. After a couple of years, there is a calibration correction for each diver that can be used to help calculate the herring biomass.

Herring diving occurs after herring have come into shallow nearshore waters and have spawned or laid their eggs on kelp. All commercial fisheries are over, or nearly over, by this time. Department herring managers and researchers create a map in ARCview GIS of all the spawned shoreline for each stock. Transect locations are determined, the dive team begins to assemble on the Kestrel and diving begins. Each herring transect begins in the intertidal area just below the trees. This insures that all herring eggs that are laid on the beach are counted. This is the only warm part of herring diving. In fact, you can get very hot walking on the beach in full dive gear.

Most of the dive team enjoys herring diving on the northern Southeast Alaska herring stocks that occur later in the spring because the weather and water tend to be warmer.

After the initial start, a count is made every 5 meters using a PVC square a tenth of a meter in size. The trick is to count the layers of eggs. Each layer of eggs is 40,000 eggs. There is a 5-meter-long string on the square and diver No. 1 swims ahead until the string stretches to 5 meters where diver No. 2 gives a tug on the string. After the string has played out diver No. 2 swims forward and writes on an underwater slate the number of herring eggs that is given to him by diver No. 1.

All communication is done through sign language except for the wide eyed look by the second diver that says, "Count faster…I am freezing." So, the lead diver travels 5 meters, stops and shivers, estimates the number of herring eggs and the second diver writes the number on the slate. This is repeated until you run out of eggs or start to get hypothermic. There is a compass on the square to ensure that the lead diver is swimming in a perpendicular line from the shoreline. Visibility is often no more than 2 feet as herring spawning time is when our spring plankton blooms occur. The string becomes your only connection to your dive buddy when the visibility is only two or three feet. Some dive sites with poor circulation have additional low visibility issues such as rotting herring carcasses, dead herring eggs and a foul smelling (and tasting) mix of seagull, sea lion and scoter feces.

Sea cucumbers, urchins and geoducks

Once herring season is over the dive program shifts into sea cucumber, urchin and geoduck diving. The standard shellfish transect is done perpendicular from the shore just like herring. Each diver has either a 2-meter stick made out of PVC pipe for sea cucumbers or a 1-meter stick for urchins. On each stick there is a compass and a slate for writing down animal counts and dive data. Each diver swims the transect while holding the stick parallel to the shore, counting the target animals seen under the stick.

Shellfish diving begins in June and ends in September and has much warmer air and water temperatures than herring dives. In addition, the divers are warmer as they are constantly moving throughout the dive and some of the large spring plankton blooms are over increasing visibility. Unfortunately, there are still summer plankton blooms that harm visibility in Southeast Alaska. One day, there can be visibility of 70 feet and the next day you can hardly see your hand in front of your face.

The Alaskan dive assessment program has earned scientific respect and has allowed for successful commercial fisheries. One added benefit is that it allows biologists and boat crew to develop long-lasting friendships that only field programs can produce and nurture.

Scott Walker is the area management biologist for the Division of Commercial Fisheries and is based in Ketchikan. His story first appeared on the Alaska Department of Fish and Game website. Used with permission.

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