Fish and Game biologists perform field surgery to study fish habits

The Alaska Department of Fish and Game is going high-tech to ensure that nobody finds out what is at the end of the rainbow.

Since the beginning of August, and continuing through fall, Fish and Game biologists are performing streamside surgeries in which radio transmitters are being placed in rainbow trout. The data will help biologists track wintering locations, spawning times locations and a wide range of data about a species that has long taken a backseat to salmon.

"For so long, all of our projects have been salmon-related because that's what the big issues have been about," biologist Sam Ivey said. "But rainbow trout are becoming a little more important in the public's eye.

"We said, 'let's start doing research on rainbows because we need to know more about their life cycles, which can help with management,'" Ivey said. "We want to see if we can manage a group of tributaries or if we have to manage them individually. We want to see signs if there is intertributary mixing with the rainbows, or if they stick to the same stream."

Chasing rainbows

Take a walk to the mouth of any of the Parks Highway streams during salmon season, and you'll likely encounter hundreds of people fishing shoulder to shoulder. The fishing pressure -- and consequently, the management -- tends to focus mostly on the five Pacific salmon runs: chinook, sockeye, pink, coho and chum. But that's starting to change.

"Oh, definitely," Tom Cloninger of 3 Rivers Fly and Tackle said about an increase in rainbow fishing among anglers. "More people are getting into fly fishing and are starting to realize you can get away from the crowds if you go upstream."

That's a double-edged sword, however. With more people comes more fishing pressure, and more signs that the rainbow trout stock could be harshly impacted.

"I'm starting to see more signs on fish that they've been caught and released than I used to," Cloninger said. "But still, it's nothing like you see at the mouths of the creeks.

"It's a lot different than the Kenai because the Kenai is such a big river and can take more pressure," Cloninger said. "But the Parks Highway creeks can't take that kind of pressure."

With more use comes more need for the proper management -- a big reason why the radio transmitter study is so important to biologists and fisheries management.

Surgery

For the federally funded radio transmitter study, only rainbow trout longer than 16 inches are candidates. Four tributaries are being fished by biologists, and every trout caught gets tagged on the dorsal fin. Through August, two trout over 16 inches are taken to the operating room each day -- the side of the creek, where Ivey and fellow biologist Jim Novak set up their tools. By mid-September, up to three transmitters per day per crew will be implanted, with two crews doing the research. In all, 150 transmitters will be implanted, in equal numbers among the four targeted streams.

"Right now we are at half effort," Ivey said. "We'll be having another crew start up in a few weeks and then we'll be doubling the effort."

The streamside operating room may be in a primitive location, but it is nothing short of sophisticated. As soon as a fish is caught, a Global Positing System coordinate is logged, as well as the fish's length, tag number and transmitter number. Ivey and Novak get the retaining "tanks" set up and filled with river water. The tools are laid out and sterilized in small plastic bins as well. When everything is as clean as a hospital operating room, surgery begins.

Using an anesthesia of spearmint oil and river water, the fish are subdued. They are then put upside down on a makeshift trough. One biologist uses a baster to continually pump the spearmint oil and river water mixture over the fish's gills to keep it breathing yet under anesthesia.

"There are a couple of essential oils you can use for this, but we chose spearmint," Ivey said.

The other biologist turns into a surgeon. A small incision is made in the fish's belly, and a long needle-like apparatus is inserted, to protect the fish's internal organs during surgery. The transmitter -- about the size of a person's thumb -- is inserted, with an antenna poking out near the tail of the trout. As the surgeon starts stitching the incision back together, the anesthesiologist alternates using basters of fresh water and the spearmint oil, eventually going to just fresh water as the fish comes out of the trance. The fish is then placed in the fresh water tank until it is able to be released. The entire process takes between six and 10 minutes.

This is the first time Susitna River tributary rainbows have been given radio transmitters. During the late 1980s, some studies were done, but technology didn't allow biologists to track rainbows using transmitters. On the Kenai River, similar studies took place last year and data is still being analyzed.

Transmitting important information

The small transmitters hold the future of rainbow trout management in the area. A radio transmitter picks up the signals of the implants, and from the air or on the ground, biologists are going to be able to track the rainbow trout for a full year.

"We'll be flying over these tributaries every other month starting in October and tracking trout movement and identifying spawn stocks, and then in April we'll start flying every other week," Ivey said. "That will tell us where the rainbows are overwintering, and then where they are spawning in the spring."

The radio transmitters' batteries work in cycles, which prolongs the life of them. Right now, they are on for seven days and then off for seven days. The schedule changes through the winter and again in the spring, but since they are all turned on at the same time, it is imperative for the surgeries to take place and to get them implanted on the scheduled days, because the entire winter's worth of research revolves around the transmitters' cycles.

The transmitters emit a sound that can be detected with a radio when tracking them. There are even different tones for different actions. One tone sounds when the trout wag their tails, which will tell biologists when they are going through ripples, and more importantly, when they are getting ready to spawn.

"When rainbows spawn, they make themselves seen and known," Ivey said. "You could probably walk across a creek and pick one out of the water when they are spawning. The transmitters will tell us when they are getting ready to spawn and where they're at."

Inside the transmitters are also motion detectors. When a rainbow trout doesn't move for a certain period of time, the transmitter will alert biologists that the fish is probably dead.

Targeting where the fish spend the different parts of their life cycles is at the heart of the research. From that data, biologists will be able to identify spawning stocks and be able to better suggest management changes to keep the fishery among the best in the state.

Management

Proper management strategies are vital to Alaska's fisheries. With proper management, long-term success of the fishery can be better predicted and carried out, but that requires research.

In the early 1980s, management was much more liberal than it is today. In 1982, the bag and possession limit went from 10 rainbows a day down to five, only two of which could be 20 or more inches. In 1983, that was dropped to one per day. Various limits have been changed throughout the last decade, and in mid-1990s, several streams went to catch and release. It's a policy many people, including local guides, are happy with.

"The rainbow fishing is great. It's come a long way since they went to catch and release. I'd love to see all of the streams go to catch and release for rainbows," said Mike Coughlin, owner and operator of Susitna Valley River Guides. Coughlin guides approximately 50 rainbow trips a year, compared to just two for salmon. "This fishery is excellent. There are more fly guys out here now and a lot less poaching going on, and it's making a big difference. If you have more fishing pressure, you have more people watching to make sure the poaching doesn't happen as much."

Biologists want to keep the rainbow trout fishery viable for years to come. After the current data from the study is analyzed, Fish and Game biologists are essentially going to do the project in reverse. Starting in the spring of 2005, they are going to track spawners --

using the data they got from the current study -- and track the migratory patterns throughout the summer. That way, they'll have an entire year's worth of research

to pull from, and they'll be able

to adjust management and regulations as a result.

"First we have to find out where they are spawning and when, and then we'll target those fish and do the study again," Ivey explained. "The main purpose of all this is to get as much information about rainbow trout as possible.

"Right now, we have to manage conservatively because we just don't know as much about rainbows as we do about salmon," Ivey said. "After we look at the data and take a look at the life cycles and migrations of rainbows, we'll be able to evaluate the current regulations and make changes if we need to. It's all to benefit the management of the fishery."

Long-term outlook

For recreational anglers like Cloninger and guides like Coughlin, a hearty fishery is important, and in turn, that means research is important. Through long-term analysis and research projects like the radio transmitter study, biologists will have a firmer grasp on what makes a fishery healthy, and what they can do management-wise to continue it.

"Within a 50-mile stretch there are half a dozen really good trout streams," Cloninger said. "I've had a few rainbows take me to school, but that's what gives me a reason to keep coming back. I'd hate to see us lose that."