AuntyM,




Sorry for the delayed response, after 2 1/2 days of listening to presentations and talking to people about salmon recovery at the AFS meeting I had to take a break and think about other things. No studies have been done that I or my "expert advisor" know of. GPS tracking of fish requires that the fish spend some time at the surface to acquire the GPS signal and if the tag has upload capability to upload information to satellites. It might be possible with steelhead, limited archival tag (they measure pressure and temperature) recoveries indicate that steelhead spend most of their time in the upper 5 meters of the water column and do spend time at the surface. Another indicator is that the stomach contents of steelhead caught on the highseas often contain bits of plastic, probably from feeding at the surface.

Highseas steelhead tagging is difficult, primarily because so few are caught. Japanese research vessels catch a few thousand chum, pinks, and sockeye, but fewer coho and chinook and only 30 to 40 steelhead in a year. The gear used is trawls, long-lines, and research drift nets. This gear is not the best for getting fish in good condition for tagging. When the vessels are stopped for collecting oceanographic data the crew and fisheries scientists fish with sport gear to catch fish for tagging. The link below had some photos and descriptions of fishing on the highseas with sports gear.

http://home.comcast.net/~kate4fish/HighSeas/kayiomaru.htm

Another problem with tagging steelhead is tag recovery. Most salmon archival tag recoveries come from commercial fisheries, hatcheries and even canneries. The UW Highseas research group has tagged a limited number of steelhead with archival tags and has only had one recovered. That was caught in a Copper River delta fishery and was turned in several weeks later after a meeting of the fisherman in the area. There was a fear that they would be penalized for catching steelhead. In past years a limited number of disc tags from steelhead have been recovered, in some cases guides tried to discourage their clients from turning in the tags. The only two other steelhead archival tag recoveries that I know of were steelhead tagged as kelts in the Cook Inlet research project I mentioned in my previous post.