Growth mystery solved; monofilament fishing line cause

Monofilament fishing line has recently been found to cause a

strange growth in trout. The link was first detected at various

Columbia Basin lakes and even in Crab Creek and Rocky Ford Creek

several years ago. Holdovers are trout that are planted one year in

a body of water and then survive the fishing season one year.

 MOSES LAKE - Monofilament fishing line has recently been found to cause a strange growth in trout. The link was first detected at various Columbia Basin lakes and even in Crab Creek and Rocky Ford Creek several years ago.

Holdovers are trout that are planted one year in a body of water and then survive the fishing season one year. They survive the winter and are still in the water during the next fishing season.

A few of these holdover trout had developed a second adipose fin. The adipose fin is a soft, fleshy fin found between the dorsal fin and the tail, which is also known as the caudal fin. This is the fin cut off at salmon and steelhead hatcheries to designate a hatchery fish from a wild fish.

When Fish and Wildlife fish biologists began receiving reports of the extra adipose fin, they couldn't believe it at first. They figured it must be an odd happening, which appears now and then with all living things, such as a greenish-blackish colored rooster pheasant appearing in 1 percent of all pheasant hatchlings.

However, when a concerned angler delivered one to the Fish and Wildlife Region Two office in Ephrata, the biologists became extremely concerned. They shipped the specimen off to state headquarters in Olympia. The biologists there asked for more samples and sent the first fish to the United States Fish and Wildlife Service Headquarters in Ballston, Virginia.

Sampling began all across the United States and into Canada and Mexico as well. The European countries are waiting for test results before beginning their sampling.

In the meantime, Region Two biologists were busy trying to catch more of the affected fish. And then the questions arose. Were trout the only species growing the extra fin? Was it only rainbow trout or were brown and tiger trout also growing the extra fin? What could trigger the extra growth?

Fish and Wildlife at all levels asked that the situation be kept a secret, so as not to alarm the public. The department confided in me, asked me to keep a journal of their activities and photograph the investigation.

I agreed, but wanted to let the public know what was going on. Because they determined the flesh of the two-fin fish was good to eat, they still wanted the situation to be kept a secret. Anglers would catch one of the fish now and then, a photo of one even appeared in the Columbia Basin Herald, but all of the people involved in the sampling and testing kept a tight lip.

An electro shocking boat was used to speed up the process of collecting affected trout. The boat, about four Fish and Wildlife employees and I would arrive at a lake after midnight, launch the boat and travel about the lake turning on the shocking device now and then. The fish would boil in the water, stunned, but otherwise not injured.

The employees would net the fish for a fast check of the fin and put the ones with just one fin back in the water. We would visit two or three lakes a night, with only 2 percent of the fish netted having two adipose fins.

The collection period lasted for five months during the spring, summer and fall of 2005. I didn't hear more for two years. Then Fish and Wildlife wanted to gather another sampling, so we went to the lakes again, after midnight and gathered more of the fish. This time the affected fish had increased into the 3 percent range.

The following winter a call from a Fish and Wildlife fish biologist in Olympia confirmed the condition was known as Afd-gotya. The first three letters stands for Adipose fin disabled, but I can't remember what the rest means, something scientific I think.

It was determined the cause of the affliction was monofilament fishing line. Somehow coming in contact with the line would trigger the extra growth. Only trout, all species of trout, may experience the second adipose fin. Tests are being conducted as this is column is being written to see if all non-braided lines or just lines from a specific manufacture are the cause.

A little monofilament line history: The DuPont company scientists invented nylon, the first synthetic fiber, in 1938. The following year they came out with monofilament fishing line.

Braided lines remained the most popular for the next 15 or 20 years because the monofilament line was considered to be stiff. However in 1959, DuPont came out with Stren, a much more limber and overall better monofilament line and it was a hit.

Today braided lines are making a comeback. Many anglers prefer them to the monofilament lines because of their strength and for other reasons too.

The switchback to braided line is perhaps for the better. Until a final determination of the specific mode, method and path the extra growth takes, fish biologists want to get rid of all monofilament. They tell me they are concerned about Afd-gotya affecting other parts of a fish.

If a trout was to survive to a third year, such as being a double-carryover, could it be possible for the trout to grow two dorsal fins? If it survived for another year, could it grow two tails?

Now that would be a spectacle, wouldn't it? Strange looking, but imagine what a tremendous fight he would master at the end of a line.

My purpose for writing this column today is to inform you my readers about Afd-gotya and to assure you there will be no long-lasting problems, at least I don't foresee any and neither does Fish and Wildlife.

However, the department has asked me to enlist for your help. If you happen to catch a fish with two adipose fins, or two of any fins, note the date, time and location. Then call the Region Two office at your earliest opportunity.

This is a call to arms, folks. Together we can help stomp out Afd-gotya.

OK, for the rest of the story check the Friday edition of The Herald, on the Outdoor Lifestyles page.