Changes in Abundance and Growth Characteristics of White Perch from the Mouth of the Bay of Quinte

Abstract

White perch became established in Lake Ontario in the 1950s, and by the mid 1960s were a major commercial species in the Bay of Quinte area. Commercial catches have fluctuated markedly, ranging from approximately 60,000 to 230,000 kg/yr between 1964 and 1978. Experimental trap nets set inshore of the mouth of the Bay of Quinte during May to July suggest a decline in white perch abundance from 1973 through 1978. However, the commercial catch did not similarly decline until 1979 when the commercial catch fell to a low of 30,000 kg/yr. The reason for this difference may be due to the fact that the bulk of the commercial catch is harvested during the winter when white perch congregate at the mouth of the bay, making fishing relatively productive. The growth of white perch was also considered, based on back-calculated growth curves of white perch caught in the experimental nets. Lee's phenomenon—a tendency for back-calculated lengths at a given age to become progressively smaller as the age of the fish from which they were computed increases—was apparent among the fish caught during this study although lacking in an earlier study. Due to the size selective nature of the fishery, an increased commercial harvest in recent years may have removed a disproportionate number of faster growing individuals from the population.