No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

A windows based computer program to compute fish back-calculated lengths at age was created using Visual Basic 6.0© programming language. The objective of this project was to develop a computer program that is user-friendly and requires minimal user input to produce back-calculations. This program incorporates the familiar windows based graphical user interface and can compute up to 10,000 fish with a maximum age of 50 years. The input data can be imported from an Excel spreadsheet or manually entered directly to the program. Back-calculated lengths were computed using the traditional Lee method [ (L; = a + [ (L, - a) ( S; / Sc ) ]. Additional related statistical outputs are also included. The output data can be viewed using Excel where it can also be formatted for individual use. The program was compared with DisBcal using yellow perch age and length data. Results of the comparison were nearly identical with differences due to a rounding function of the output data. / Department of Biology

Food habits of the alewife, Alosa pseudoharenous, were studied in Indiana waters of Lake Michigan at 10 m (32.8 ft.) stations o transects at Burns Ditch and Michigan City from June to October, 1970. Organisms in stomachs were expressed as percent of the total volume, percent frequency of occurrence, and percent composition.Food selectivity of the alewife was studies at the 10 m station on Michigan City transect. Plankton samples were taken concurrently with fish samples and percent composition of various food items in plankton and stomach samples were compared to elucidate selection with an electivity index.The occurrence of copepods and cladocerans in alewife stomachs from Burns Ditch and Michigan City transects was similar; however, Michigan City alewife stomachs had three more cladoceran species than Burns Ditch samples. Oligochaetes were not present in any Michigan City stomach samples, and Pontoporeia affinis was not found in any Burns Ditch samples. When comparing these two sample sites, the alewife food habit differences may be due to difference in substrate, water quality, and the influence of the Burns Ditch river mouth.Based upon frequency of occurrence and percent volume, zooplankton comprised the largest portions of food in adult alewife (140 mm [5.5 in.] and greater) alewife stomach samples taken from June to October in 10 m of water on Michigan City transect. Cladoceran occurrence and percent volume in alewife stomachs increased monthly from June to September and October. Cyclops bicuspidatus, the major food item contributing to copepod percent volume in alewife stomachs, generally declined from July to October.Alewife size, for fish ranging from 140-169 mm (5.5-6.6 inc.) and 170-189 m (6.7-7.4 in.) did not appear to influence percent volume and frequency of occurrence of major food items consumed. Food selectivity of the two size groups was also similar for planktonic food species examined.Alewives ranging from 140-189 mm selected positively for the female Cyclops bicuspidatus while copepodites were always negatively selected. During October, large cladocerans, Leptodora and Daphnia, were positively selected. Although Diaptomus spp. Were similar in size to the female Cyclops, it was always negatively selected. The alewife selection for Bosmina longirostris was strongly negative in June, July, and October, but ws near random in August and September. Since the B. longirostris density in August and September was relatively high, the near random E values may indicate random filter feeding by the alewife. Prey size, mobility, and density appear to be major influences on adult alewife food selection.

Experiments were conducted to determine the effect of aquarium volume and feeding regimen on growth in length and weight and on food conversion efficiency by bluegill fed rations of mealworms. Two 30 day periods were utilized for each study. Part one, which examined the effect of aquarium volume on growth extended from January 20 to February 18 and from March 27 to April 25, 1972. Part two, which examined the effect of multiple feedings compared with single feedings on growth, ran from May 30 to June 28 and from July 1 to July 30, 1972. The studies were conducted in a controlled environment aquarium. Food consumption, growth and food conversion by individual fish in each experiment were monitored closely. All conditions with the exception of the testable variable were held as constant as possible. Water quality was monitored and judged to be within acceptable limits for fish culture.Aquarium volumes of 5, 10 and 15 liters did not affect growth in length and weight or food conversion efficiency of individually held bluegill.A 30 day daily regimen of one feeding compared with three feedings of a constant ration of mealworms resulted in significantly greater length, weight and conversion efficiency for multiple-fed male bluegill. After 60 days length and weight were not significantly different but conversion efficiency was significantly greater for multiple-fed male bluegill.

There is no abstract available for this dissertation.