POPULATION DENSITY, AGE CLASS COMPOSITION AND PRODUCTIVITY OF THE LARGEMOUTH BLACK BASS, MICROPTERUS SALMOIDES (LACEPEDE) IN AN UNEXPLOITED NORTHEASTERN LAKE (NEW YORK)

GERALD RICHARD IWAN, Fordham University

Abstract

The population dynamics, growth, survival, food habits, distribution, biomass, standing crop and production of the unexploited largemouth black bass population of Calder Lake, N.Y. were determined in 1974-1975. Results were compared with ecological parameter data for possible interrelationships and evaluations were made of the efficacy of various techniques employed in the study.^ The largemouth black bass population was estimated by electrofishing at 1686 (+OR-) 158 bass aged 0('+) - XI('+), equally divided between males and females and heterogeneously distributed with the highest densities occuring in warm, weed, literal areas. Statistical analyses (p = 0.05) showed few differences by location in physical or chemical parameter measurements to depths of 3 m or for bass distribution by size. Catch per unit of effort was higher for electrofishing at 25.3 bass per hour than for angling at 4.7 bass per hour. Total processing mortality was 0.35% and the incidence of natural physical deformities or injuries was 10.6%.^ Feeding incidence averaged 41% with the highest percentage (40.1%) of full stomachs occurring in Summer in 1975. Percent food to body weight was also highest in Summer at 1.2-2.5%. Bass fed opportunistically in 1975 on crustaceans (43.8%), insects (36.0%) and fish (17.8%).^ Bass movement was limited (< 100m) for 82.6% of the population but dramatic redistributions occurred when 1 m temperatures fell below 6.1(DEGREES)C or reached 29.4(DEGREES)C. Winter aggregations were discovered at 3 m depths adjacent to normally high density areas when 1 m temperatures fell below 6.1(DEGREES)C.^ The length-weight relationship was allometric and defined by W(g) = 0.000019 (.) 1('2.9132)(mm). K(,TL) values were 1.3-1.5 for bass < 0('+) and back-calculated lengths and weights ranged from 98.0-455.8 mm and 13.3-1049 g for ages 0('+) - XI('+).^ The population was dominated by age class II, which represented 56.41% of the total. Age class survival (II XI) was 53.2% with an instantaneous mortality rate of 0.561. Total biomass and standing crop values were moderately high at 118.475 kg and 48.576 kg/ha with an area maximum of 115.386 kg/ha. Total production was 36.914 kg contributed by 110.461 kg from age class II.^ The observed conditions were typical of a stunted population. High biomass and standing crops were concluded to be a function of food and density related ecological factors which optimized production for ages II and younger bass.^

Subject Area

Ecology|Aquatic sciences

Recommended Citation

IWAN, GERALD RICHARD, "POPULATION DENSITY, AGE CLASS COMPOSITION AND PRODUCTIVITY OF THE LARGEMOUTH BLACK BASS, MICROPTERUS SALMOIDES (LACEPEDE) IN AN UNEXPLOITED NORTHEASTERN LAKE (NEW YORK)" (1983). ETD Collection for Fordham University. AAI8323530.
http://fordham.bepress.com/dissertations/AAI8323530

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