consolidated inlet. Rather, they had numerous, ephemeral runoffs 

 from surrounding snow and ice fields. 



Food Habits 



Lakes harboring golden trout all had their individuality 

 regarding consumable organisms available to fish diets. Specific 

 studies on six Absaroka-Beartooth lakes revealed golden trout 

 were not totally opportunistic where menu choices were available. 

 Golden trout populations in Montana were found in three types of 

 lake habitats: 1) eutrophic, pond-like lakes; 2) small, somewhat 

 shallow oligotrophic lakes and 3) large oligotrophic lakes (Table 

 6) . 



Those fisheries in the eutrophic class were more opportunis- 

 tic feeders, utilizing numerous items. The mainstay in these 

 habitats appeared to be mostly dipterans and Gam marus. 



With the exception of Sylvan Lake, goldens occupying small 

 oligotrophic lakes were usually part of a string or chain of 

 lakes. Populations of fish were often dependent on reproduction 

 upstream. The occupants of small, oligotrophic lakes are small 

 to medium sized fish with an occasional larger 1 1/2 pounder. 

 These lakes supported less invertebrate diversity than eutrophic 

 lakes. Food organisms were taken from the benthic to surface 

 zone, depending on the season. Dipteran pupa taken in the water 

 column represented the overwhelming food consumed. 



Large oligotrophic lakes usually supported larger golden 

 trout. Diversity of invertebrates was no greater than that found 

 in small o]igotrophic ]akes, but the quantity of organisms was 

 higher. Typical zooplankton density was 450-900 per cubic meter 

 of water in large lakes compared to 50-200/m-^ in small oligotrop- 

 hic lakes. Zooplankton of the large varieties (+2 mm) were 

 usually absent in smaller, shallower lakes. Of those lakes 

 listed in Table 6, only Blue Danube failed to produce large fish 

 in 1981. Benthic organisms were preferred nourishment in large 

 oligotrophic lakes. 



Table 6. Class of lake habitats with golden trout in Montana 



Small Eutrophic 



Small Oligotrophic- 



Large Oligotrophic 



Hidden #5, 6, 7 

 Golden Trout 



Little Lightning 



Sylvan 



Hidden #2 



Island 



Crescent 



Heart 



Lightning 

 Sav/tooth 



Fourmile Basin #4 

 Blue Danube 

 Cave 



-'-Sometimes referred to as Mesotrophic. 



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