Abundance, Growth, and Condition of Yellow Bass, Morone Interrupta Gill, in Clear Lake, Iowa, 1941 to 1951

Abstract

Scales and data were collected on over 3,500 Clear Lake yellow bass in 1941–1943, and 1947–1951. In 1941 to 1943 most of the yellow bass in the anglerˈs catch were from the 1939 year class with a few from the 1937 year class. From 1945 to 1951, angling, seining, and gillnetting showed no marked change in the abundance of yellow bass. The 1938, 1940, 1941, 1947, and 1950 year classes contributed few or no fish to the later catches. In 1947 and in 1950 young of the year, were present but apparently few of these fish survived 1 year. The 1939, 1943, 1946, 1948, and 1949 year classes were particularly abundant. Young yellow bass were larger in early July during the years with above normal June air temperatures than during years with cool June temperatures. Most growth in length occurs in the first three years of life. The growth rate decreased from 1937 to 1949 but was more rapid again in 1950 and 1951. In 1947 growth was slow until after July 1, probably as a result of low May and June temperatures. In 1949 little growth took place from July 1 to August 26. In 1948 and 1949 the ponderal index decreased as the season progressed, but this trend was lacking in 1947, 1950, and 1951.