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HomeMy WebLinkAboutAPA707i I _____ --------- Wantana Impoundment Hoose Census March 1983 Susitna Joint Ventu re Document Number WATANA IMPOUNDMENT MOOSE CENSUS, MARCH 1983 On 28 March, 1983, I censused an area bordering the Susitna River from the site of the proposed Watana dam upstream to the upper reaches of the high pool level (2200 ft elevation) between the mouths of Oshetna and Tyone Rivers. Included in the survey area was not only the impoundment zone below the 2200 ft level, but an additional 0.25 mi border adjacent to the high pool level. The total planimetered area censused was 104.8 mi 2 , of which almost 8 mi 2 was water, bringing the total area censused to 96.8 mi 2. A total time of 396 min ~as spent on the census. Conditions for the census were poor due to lack of suitable fresh snow. Sur·1ey methods have been d~scribed by Gasaway et al. (1981). The entire im- poundment area was censused at 4.0 min/mi 2 , and then an area of approximately 3.4 mi 2 was selected at random and censused at 12 min/mi 2 in order to esti- mate the number of moose missed in the less intensive survey. The more in- tensive search resulted in a sightability correction factor (SCF) of 3.6, further substantiating the.feeling that count conditions were extremely poor. To obtain a more reliable estimate of numbers of moose utilizing the im- poundment and adjacent areas under these poor conditions, a much more in- tensive search resulting in prohibitive expenditures would have to be made. To lend further credence to the SCF, results of radio-tracking effor~s done the day prior to the census were investigated. On the census, only 2 radio-collared moose were seen. Radio-location data revealed that there were 7 moose in the impoundment zone, suggesting that the calculated SCF of 3.6 was reasonably accurate. Below are the results of the census flown in a Supercub at 4.0 min/mi 2 with Ken Bunch on 28 March 1983. /' -; I-3,:. Moose observed * (SCF * 1.03) = estimate of actual numbers -- 161 * (7/2 * 1.03) = 580.4 Obse~ved moose/mi 2 = 1.6G. Estimated moose/mi 2 = 6.0 ~ It is interesting to note that between the upper end of the impoundment and Kosina Creek, 11 kills were seen. Because of the absence of snowfall in the last 3-4 weeks, many of the kills were undoubtedly at least that old, but I find it interesting that we would see that many predator kills and/or natural mortalities. • • • 1 observed 16 calf moose during the 1983 census. This equates to ap- proximately 13 calves per 100 cows. The 1982 Watana impoundment census showed 35 calves in a total sample of 173 moose, equivalent to approximately 30 calves/100 cows. Additionally, it should be noted that of the 161 moose observed in 1983, only 52 (32%) were below the high pool level. In 1982, 70 of 173 (40%) of the observed moose were below high pool level. The gen- eral trend in 1983 therefore, seems to be a slightly less severe winter, thus the moose were at higher elevations and thus fewer total moose were counted and a lesser percent of that total were below the 2200 ft level • i !~ I I • Quad Name and Number Talkeetna Mtn. C-1 Talkeetna Mtn. C-2 Talkeetna Mtn. 0-2 Talkeetna Mtn. D-3 Talkeetna Mtn. D-4 TOTALS ~ •• • 1983 WATANA IMPOUNDMENT MARCH MOOSE CENSUS No. Moose b~ Age Class No. Moose b~ Elevation Adults Calves Unknown Under 2200 ft Above 2200 ft Total Moose 21 4 0 0 25 25 31 4 0 4 31 35 32 6 0 14 24 38 61 2 0 34 29 63 0 0 0 0 0 0 145 16 0 52 109 161 • •• • 1982 WATANA IMPOUNDMENT MOOSE CENSUS No. Moose b~ Age Class No. Moose bt Elevation Quad Name and Number Adults Calves Unknown Under 2200 ft Above 2200 ft Total Moose Talkeetna Mtn. C-1 46 18 2 19 47 66 Talkeetna Mtn. C-2 19 2 3 8 16 24 Talkeetna Mtn. D-2 . 26 8 5 10 29 39 Talkeetria Mtn. D-3 28 7 6 30 11 41 Talkeetna Mtn. D-4 1 1 1 3 0 3 TOTALS 120 36 17 70 103 173 • • • • i . DEVIL CANYON IMPOUNDMENT MOOSE CENSUS, MARCH 1983 On 31 March, 1983, I flew the impoundment area of the proposed Devil Canyon dam to census moose, using methods described by Gasaway et al.(l981). The survey area ran from the proposed damsite supstream to approximately ?ne mile upstream from the confluence of Tsusena Creek with the Susitna River. As with the 1983 Watan Impoundment census, this survey included the high pool level (1450 ft. elevation) and an area 0.25 mile adjacent to and including the high pool level. The total area censused was 29.98 mi2. Survey time as 123 minutes. I flew with Ken Bunch in a SuperCub. Census conditions were poor. Sub-standard visibility from the many patches of ground showing in the snow v1as further compounded by moderate turbulence, particularly in the lower census area with its high rocky abutments. The entire census was flown at 4.1 min/mi2. An intensive senrch arcc of 1.69 mi 2 was flown for 21 minutes, at 12.4 min/mi 2 . Hm·1ever, no moose were seen during the intensive search. I decided that the turbulence and extremely poor sighting conditions were good reasons for deciding against doing another intensive search . Census results follow: Moose observed = 14 Moose/mi2 2 = 0.47 moose/mi All moose seen were adults. Of these, 10 (71%) were above the high pool level. Without a SCF, this number is useful only as a minimum number of moose in the survey area. Radio-tracking flights on the same day as the moose survey located two moose within the survey area. Only one of these moose was counted during the survey. If the actual area of habitat useable by moose in the census area were measured, this might also change the estimation of moose numbers in and adjacent to the impoundment, as some of·the area censused consists of steep cliffs unlikely to harbor moose. I suggest that in planning future surveys, good visibility {e.g., fresh snow) may well be a more important criterion for census scheduling than calendar date . • Quad Name & Number Talkeetna Mtn. D-4 Talkeetna Mtn. D-5 I TOTAL •• 1983 DEVIL CANYON IMPOUNDMENT MARCH MOOSE CENSUS No; Moose (adult) 9 5 14 No. Moose by Elevation Under 1500 ft. Above 1500 ft. 3 1 4 6 4 10 ' ..., • ' ~ ..