During most seasons many of those who visit Crater Lake National Park go down the trail to the lake. Usually quite a number of these people try their hand at fishing, either from boats or from the shores. Hasler and Farner (1942) report that 1270 anglers who fished from boats on Crater Lake in 1937 took 1302 fish -- an average of a little more than one fish per angler for the season, which included the months of July and August. The same authors made similar reports for the seasons of 1938 through 1940. In 1940 their observations show that 837 anglers caught 4188 fish, or an average of about 5 fish per fisherman. In addition to these records, the creel census report for 1950 (Crater Lake National Park files, no author) states that in July and August of that year, 229 anglers averaged 1.12 fish per person. Since it is obviously very difficult to obtain records of shore fishing, none of the above figures include such data.

From the standpoint of the fisherman -- to say nothing of those who just wanted to view the lake from the shore, or to ride upon its surface -- the 1952 season was a great disappointment. Excessive snows of the previous winter, coupled with a late spring, made it evident very early that the lake trail would not be opened by the beginning of the season. A more thorough investigation indicated August 1 to be the probable earliest date that the 1.6 miles of trail could be made passable. That meant, of course, that July, the best fishing month (Hasler and Farner, 1942) would pass with the lake inaccessible to visitors.

According to plan, therefore, a crew began to clear snow and repair damaged portions of the trail. The work, in spite of great difficulties, progressed about on schedule. Then, with completion anticipated to be only one or two days away, the final blow fell. Several daily rains had loosened the soft material along the face of the wall, and a particularly heavy storm released an avalanche of many tons of rocks, debris, and water which rushed down the slopes and washed out completely the lower part of the trail. This made necessary so much new permanent construction that the lake remained closed to visitors for the entire season.

Although Crater Lake is by no means a fishing resort, it is of scientific interest to make yearly observations of the fish and of conditions which affect their existence there. Along this line there was planned for 1952 an extensive investigation of limnological conditions and of life in the lake in order that more might be known of the fish population. It was hoped, also, to be able to learn something of how large a fish population the lake might support. Difficulty of reaching the lake, however, greatly hampered such operations. Very few data, therefore, have been collected.

The first trip of the year to the lake -- and to Wizard Island -- was made by the author on July 13 in company with Paul Herron, who was to have operated the launches for the Crater Lake National Park Company, and Wallace Ernst, one of the other ranger naturalists. Since the trail at this time still was almost completely covered with snow, descent was made along one of the ridges where trees were of great assistance in maintaining footholds. Despite this, however, much of the way was over snowbanks with travel on "all- fours." At the lake shore a row boat had been secured high in a tree the previous fall to protect it from snow damage. This was lowered and placed in the water for the trip to Wizard Island.

Before heading across the lake, we rowed around to a point where Joseph Diller, who made the first extensive geological studies of Crater Lake, was supposed to have placed a bronze tablet on a rock face. The tablet has apparently been gone for some years but the imprint remains clearly marked. If the information is correct that the bottom of the tablet was at water level at that time, 1873, the present water level is an estimated six feet below that point. According to Paul Herron, however, the water appeared to be considerably higher than last season. At Wizard Island, also, evidence of the higher water was observed. One of the government boathouses, constructed in 1942 with its lower sill eighteen inches above water level, is now so nearly submerged that the gunwale of the rowboat would just slip under its eaves. Later in the season -- August 19 -- the water level was measured by Paul Herron and the author. It was found to be 11 feet 1 inch below the October 1, 1942 level. Also, it was estimated from pollen deposits, that the water was about three inches lower than on July 13 of this year.

In 1952, surface temperature readings, taken with a standard laboratory thermometer, were obtained from shore on August 3, 7, and 17. These were, respectively, 17.3° C. (63.14° F.), 16.8° C. (62.24° F.), and 16.9° C. (62.42° F.). The first and last of these were taken below the Wineglass, and the other near the foot of the government trail. At this writing, only one open-water surface temperature reading had been taken. This was between government trail and Wizard Island on August 7 and was 16.3° C. (61.34° F.). Thus, temperatures this season appear to be nearly the same as maximum for 1937.

Although only official personnel were permitted access to the lake, there was some fishing this season by local residents who managed to get down to the lake. Fortunately, a few of these records were obtained. Seasonal Ranger Bob Morris contacted one group of anglers who had taken 31 fish -- 30 Rainbow trout (Salmo gairdnerii irideus) and one Sockeye salmon (Oncorhyncus nerka kennerlyi) -- on July 27. These were caught with dry flies cast from shore. The trout ranged from ten to sixteen inches in length, and the salmon was ten inches long. No viscera were obtained but the fishermen said that some of the Rainbows were spawning, while others had already completed this function.

The following week, Ranger Morris also contacted a group of three anglers who had caught seven Rainbows with similar tackle. Records of four other Rainbow trout and two salmon were obtained by the author. The trout were from nine to slightly over thirteen inches in length, and the salmon between eight and nine inches. This total of 42 fish undoubtedly does not include all those taken but it is an interesting comparison with the figures cited in the introductory paragraph.

At the date of this writing, three -- two Rainbow trout and one Sockeye salmon -- of four fish stomachs collected had been examined to study food habits. The trout had been caught from shore, and the salmon was taken on a troll line from Skell Channel. It is of interest to observe that availability of a food item would appear to be the important factor in its selection by the fish. These fish were taken at the time of the California Tortoise Shell butterfly emergence when great numbers of these insects were flying over the lake. Many of them could be seen floating on the water where they had probably fallen exhausted. The stomachs of the salmon and one trout contained, respectively, nine and six of these butterflies.

One further item of some note was the finding of a single specimen of a copepod, Cyclops serrulatus, in the stomach of the salmon. This, in itself, would not seem important since microcrustaceans of the copepod group usually are found in most lakes and ponds. In looking through the available literature on previous studies of Crater Lake, no reference to this particular group of animals could be located, although their near relative, Daphnia (the water flea), was mentioned by several authors. It is not known, therefore, if copepods were not in the lake when the other investigations were made, or if they were overlooked. Microcrustacea are important food items, particularly for small fish, and sometimes compose a portion of the diet of larger fish. Consequently, it is gratifying to note their occurrence here.

The foregoing is a very meager gleaning as compared with many previous seasons. The only indication of fish abundance seen this year was the observance of considerable surfacing by the fish one day in late July. This does, however, give some indication of present conditions in Crater Lake.

References

Hasler, Arthur D. 1938. Fish biology and limnology of Crater Lake, Oregon. Journal of Wildlife Management, 2(3):94-103.

Hasler, Arthur D. and D. S. Farner. 1942. Fisheries investigations in Crater Lake, 1937-1940. Journal of Wildlife Management, 6(4): 319-327.

Kemmerer, George, J. F. Bovard, and W. T. Boorman. 1923-1924. Northwestern lakes of the United States: biological and chemical studies with reference to possibilities in production of fish. Bulletin of the Bureau of Fisheries, 39:51-140.