A Ten-year Summary of Enhanced Chinook Harvested in the Winter Troll Fishery

Most of the chinook produced in SE Alaska hatcheries, all other things being equal, will quickly swim away from inside waters and generally move toward the north and west through the course of their first summer.  Some will stay near shore as they head north, some will not.  A portion of the young fish will remain behind in inside waters in SE, though that portion is not generally thought to be large.

Genetics, age of the smolt and size of the smolt all play a role in determining what a released smolt will do, but none of those things is an absolute determinant.  Real world experience is also a factor as is chance.  If a smolt finds a sudden irresistible attraction to its left, there is a good chance it will turn left…even if the majority of the fish turn right and in years proceeding have always turned right.  If that attraction is strong enough and long enough there is certainly a chance the fish will not follow the most frequented route of its relatives.  But, generally there is a good reason for fish to go where most of them go.  A simple way to understand this is that the sum of things that would be good for the fish and otherwise attract the fish are most likely to occur along the historically most traveled path.  So much so that the vast majority of fish of a given stock released from a given site generally follow the same route.

With a general movement north and offshore moving toward distant waters, most fish released from SE Alaska hatcheries would not be expected to be foraging in winter in areas where they can be harvested by SE trollers from October through April.  At the same time, a number of them do hang around or return to these waters as catchable sized fish during the winter.  Some have probably stayed their entire lives in SE Alaska waters while some may have made a large circle in the Pacific over several years and have come back, well before any spawning urge, to these same waters. 

As is the case with all chinook harvest in SE Alaska a large proportion of the harvest is examined for coded wire tags.  Tagged fish are visually detectible as the adipose fin is also removed from tagged fish.  About 10 percent of the chinook released from Alaska enhancement programs are tagged, so each tag found represents 10 fish, not one.   There is a new complication in the recovery process, currently missing adipose fins do not necessarily mean a fish is tagged.  Washington and Oregon are clipping adipose fins from all enhanced chinook.  This is the only way they can identify and harvest enhanced fish while releasing naturally produced fish – that are not clipped.  So, it is no longer easy to quickly estimate the enhanced component of the catch since all of the lower 48 origin fish are adipose clipped while only 10% of the Alaska enhanced fish will be clipped and tagged.

All these complications aside, ADF&G port samplers look at a significant portion of the troll harvest to recover coded wire tags and determine the origin of the fish.  Each year Ron Josephson, the director of the ADF&G Tag Lab, puts out summary tables listing the origins of enhanced fish caught in the SE Alaska winter troll fishery.  We have taken that data and constructed 3 tables:  one showing coast wide distribution with the state or province of origin, another showing SE enhancement agencies (SSRAA, NSRAA and DIPAC) contribution by agency, and a third showing the contribution of SSRAA’s various release sites.  The second table has an “Other Alaska” designation.  These fish are from Little Port Walter, Port Armstrong, Tamgass (Metlakatla) and several small projects.

It is far more likely that SE Alaska enhanced chinook are caught in Spring Troll Access Fisheries, than in winter troll.  In fact, it is a little surprising so many of these fish are within the range of SE Alaska trollers during the winter period.  This is positive in that it both adds to the winter harvest when the fish have their highest value and these chinook are not counted against the treaty cap…something that is even more important in light of the most recent US/Canada Pacific Salmon Treaty.

 Coast Wide Enhanced Chinook in Alaska Winter Troll (Oct-Apr) Harvest
 

 Alaska Hatchery Contribution to Alaska Winter Troll Chinook Harvest