The Haas Discriminant Method uses several physical characteristics such as chin bone counts to determine the difference between bulls and dollies. BUT, this method is probably not effective with Puget Sound populations. With all other populations that have been examined, the method is about 90 percent accurate--i.e., you see overlap in physical characteristics in only about 10 percent of the cases.
Curt Kraemer used the method on Skagit char and found a 60 percent overlap in physical characteristics, therefore it was not very effective in telling the two apart. At first it was thought that the bulls and dollies were interbreeding, but genetic testing showed that there were indeed two species, not one species with genetic characteristics of both. Genetic testing is still the only way to determine for sure which are Dollies and which are Bulls. Curt currently estimates that about 85% of the char in the Skagit are bulls, and about 15% are dollies. This is subject to change as so few fish have been tested genetically. But our current understanding would suggest that you probably caught more bulls than dollies.
One possible reason for such overlapping characteristics between dollies and bulls in Puget Sound is the fact that such a large percentage of them are anadromous. Only in Puget Sound streams and WA coast streams have anadromous bull trout been found. All other bull populations that have been studied are resident, including Oregon and BC. And most Dolly populations, of course are anadromous. So if our char behave more like anadromous dollies, then it may follow that anadromous bull trout would have very similar physical characteristics. None of this has been tested, though.
Fish Pirate, where did you get the info regarding char predation on salmon smolts? They certainly feed and follow the smolts downstream, but once they get into the salt, they seem to like feeding on the larger surf smelt. If you look at "dolly beaches" in the Camano Is/Port Susan area, and overlap a WDFW surf smelt spawning beach survey map, the two are strongly related, leading biolgists to believe that smelt are also very important in the diet of char.
[ 04-16-2001: Message edited by: obsessed ]
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