Fungi imperfecti were cultured from water and bottom sediment samples collected at four locations of Utah Lake. These study sites included: (a) The mouth of Provo River, the largest fresh-water tributary entering Utah Lake, (b) Mud Lake, a large shallow area known for its high nitrogen content, (c) the entrance of the Spanish Fork River into the lake, a large fresh-water tributary containing wastes from industry and agricultural enterprises, (d) Jordan River, the only natural outlet of Utah Lake. One hundred and thirty-eight species of fungi imperfecti were identified. A total of 89 species were isolated from the Spanish Fork River, 107 species from Mud Lake, 82 species from the Provo River, and 60 species from the Jordan River Outlet. Species that were restricted to a particular area included, 16 from the Spanish Fork River, 17 species from Mud Lake, 7 species from the Provo River and 6 from the Jordan River Outlet. The total number of fungi cultured from each station was in a direct relationship to the percent organic matter present. Seven species of Aspergillus which are potential human and animal pathogens were identified. Potential plant pathogenic fungi identified included 22 species.

Information on the nesting of the White-faced Ibis (Plegadis chihi) in Utah County is presented for the first time. Nests built in hardstem bulrush (Sciprus acutus) settled from an average height of 120.8cm on June 9 to 93.6cm on June 27, 1971. Nest spacing ranged from 2m to 9m, averaging 4.6m. Invertebrates of the class Arachnida and the insect orders Coleoptera, Homoptera, Lepidoptera, and Thysanoptera were collected in a Berlese funnel. Average clutch size was 3.17. Egg length and width averaged 51.40mm X 36.75mm. Average volume was 36.93cc. In 21 study nests, 45.8 percent of the eggs hatched, beginning on June 8 and ending on June 27. The young weighed approximately 26gm at hatching, with tarsometatarsus and bill each 15mm long. These increased to 400gm, 70mm, and 45mm, respectively, in 15 days. Feather shaft had grown to over 100mm. Major food items of the nestlings were larvae of the insect families Dytiscidae, Hydrophylidae (O. Coleoptera) and Stratiomyidae (O. Diptera). Ectoparasites collected were a louse, plegadiphilus plegadis, and three unidentified flies.

This study of the distribution of the fresh-water sponge, Meyenia fluviatilis, at the Lincoln Beach area of Utah Lake involved the following: First, sampling of the area for the presence or absence of the species. Second, sampling at two separate areas at different depth intervals to determine if the number of sponge colonies and colony size were in any way related to depth. Finally, monthly sampling at one area to determine when gemmules of M. fluviatilis were present in the sponge colonies. Meyenia fluviatilis was found to be commonly distributed in 1-2 m of water on the lower surface of the larger rocks at 30 transects approximately 100 m apart. At the 1-2 m depth interval, the largest number of colonies (36 colonies per 50 rocks at area A and 69 colonies at area 8) were recorded. The average colony size was also greatest at this same depth (21.5 cm for area A and 26 cm for area 8). The lowest monthly percent of gemmules observed at area 8 occurred in June (22 %), while August was the highest observation with 70 %. Gemmules were observed every month and no sponge colony disintegration was observed during any month.

Information about the benthic macroinvertebrate populations along the eastern shore of Goshen Bay, Utah Lake, Utah, can be used, in part, to determine future management of the lake. In the project herein reported, cement artificial substrate samplers were used to sample two types of substrate: rubble and compacted calcareous tufa. Monthly samples were obtained from each type of substrate from March 1972 to May 1973. An amphipod, Hyalela azteca and a chironomid, Dicrotendipes fumidus were the dominant organisms in numbers and tiomass. Amphipod numbers were dependent upon the amount of algal standing crop. Elimination of this area could affect the trophic structure of the lake by effectively reducing the macroinvertebrate population of the lake.

Utah Lake, located in Utah County, north-central Utah, is one of the most important natural fishing lakes in the state. The spawning ecology of the white bass (Roccus chrysops) was studied in Utah Lake between 1964 and 1966. Gill nets and seining were the primary means of sampling. The spawning location was sampled every other day throughout the spring and early summer of 1966. Three major winter schooling areas were found: Provo Bay - Creer Access south to the mouth of Spanish Fork River, Lincoln Beach, and off Ludlow Barn. There appears to be extensive winter feeding and movement among the white bass populations. Immature white bass of both sexes were found in large numbers throughout the entire lake during the summer. In the early spring months, bisexual schools of mature bass concentrated in the southern portions of the lake before forming into unisexual schools in mid-April. Spawning activities were restricted to an area adjacent to Lincoln Beach, 0.25 mile and to a depth of 60 inches. Rubble, interspersed with ledge rock and boulders, were the only bottom types selected for spawning. An area surrounding Bird Island also simulated the bottom types off Lincoln Beach, but was not utilized for spawning. Gravid females were taken in the vicinity of Lincoln Beach on May 6, 1966 when water temperatures had reached 63° F. Spawning activity lasted from 10 to 15 days in mid-June in water temperatures of 69° F. Unisexual schools of gravid females were found off Creer Access a distance of three miles from the spawning grounds. Small numbers of female bass would migrate to the spawning site, spawn, and return to the vicinity of Creer Access, never remaining over the spawning site longer than to spawn. Tributaries were not utilized for spawning, although bass were sampled feeding in the Provo River in mid-August. Turbidity of Utah Lake during the spring and summer prevented any observations of spawning activity or behavior. Summer sampling throughout Utah Lake in 1965 resulted in a 2:1 (174 males - 93 females) sex ratio. However, these figures are in conclusive as they did not include gravid females.

Mud Lake marsh lies east of Utah Lake between the cities of Provo and Springville in Utah County. Since 1936 it has become a polluted, odiferous, silted area. A study was conducted on the aquatic invertebrates during the summer of 1962 (June 19 to September 20). An .01 meter2 bottom sampler was used at 30 random stations. Each station was sampled once a week. Water depth, mud, water and air temperatures were taken at each station. Dissolved oxygen (Winkler method) and ion resistance (Wheatstone bridge) were taken each day. The aquatic invertebrate community consisted of benthic (Diptera, Oligochaeta, Nematoda), interphashic benthic (Cou{ri}xidae) and planktonic (microcrustacae, rotifera, algae). The benthic portion of the community was adequately sampled, the other two portions were not. Dipteran populations were: Chironomidae larvae - numerous throughout season; Tabanidae larvae - found occasionally; Tipulidae - increased in late summer; Ephydridae - increased in late summer. The Chironomidae population increased slowly until the first week in August, then increased rapidly with peaks in late August and early September. The population numbers dropped when water levels were below .5{6}mm and temperatures dropped below freezing. It is supposed that the dissolved oxygen became the limiting factor in low water levels because of heat increases in bottom temperatures as the water level dropped. An experiment with an aerated control gave experimental evidence for this hypothesis. The Oligochaet population showed no close relation to these physical factors.

This study attempts to give a preliminary survey of the marsh habitat in Powell's Slough near Utah Lake. The following aspects are treated: seasonal waterfowl utilization of the slough, productivity of nesting water-fowl, description of the vegetation, invertebrate analysis, and analysis of environmental factors that may influence the habitat.

The aquatic and semi-aquatic plant communities of Utah Lake, Utah County, Utah are discussed. This discussion includes the methods of describing and delimiting the major vascular plant communities, the descriptions of the present existent communities, and the determination of the vegetational changes, particularly since 1925. The vegetation around Utah Lake is divided into plant communities. Each community is discussed using: (a) quantitative data, (b) field observations, (c) general and specific locations of the community, and (d) interrelationships and trends of the community. Historical vegetational changes of Utah Lake plant communities are discussed. In this discussion, the plant communities described by Cottam in 1925 are examined in broad outline and then in detail. In 1968, twenty-nine plant communities had developed from fifty-six per cent of the associations and twenty-nine per cent of the societies that were described by Cottam in 1925.

Research on the nesting of the Double-crested Cormorant (Phalacrocorax auritus auritus) was undertaken to determine the nesting ecology of the bird on Utah Lake, Utah County, and the possible effects that diking Provo Bay would have on the cormorants breeding there. In 1973, two colonies in Provo Bay were visited weekly to determine laying dates, incubation period, clutch size, and hatching dates. Another colony, located on the dike of the Geneva Steel Reservoir, was visited daily during the spring and summer of 1973. At this colony, egg-laying occurred from 13 April to 17 May. The average clutch size was 3.8, and the egg length and width averaged 60.50 mm x 39.05 mm. An average egg volume of 49.0 cc is first reported for the subspecies. The average period of incubation was 28 days, and 29.5 percent of the eggs hatched, beginning on 20 May and ending 9 June. The young weighed an average of 36 gm at hatching with a beak length of 17 mm and tarsometatarsal length of 11 mm. These increased to 1543 gm, 73 mm, and 58 mm, respectively, in 23 days. The cormorant population on Utah Lake may be severely reduced by the diking of Provo Bay.

The reproductive biology of the brooding leech Helobdella stagnalis (Linnaeus) in Utah Lake was studied for an 18 month period from June 1970 to December 1971. In determining the annual reproductive cycle, the number of adult leeches carrying eggs or young were counted at weekly intervals during the reproductive season and monthly during the rest of the year. Gonadal staging data from histological sections were correlated with the field collection data. It was found that two broods of young were produced by the adult animals during the reproductive season. Continuous water temperatures were recorded at the study site throughout the period of this investigation. Temperature was found to have an effect on the rate of gametogenesis, development, and the number of broods produced. The gonads have an off-on type of activity. When the testes are active, the ovaries are dormant and vice-versa.