Population Characteristics of Adult Pink Salmon in Two Minnesota Tributaries to Lake
By Joseph P. Nicolette, George R. Spangler
Journal of Great Lakes Research, Volume 12, Issue 4, 1986, Pages 237-250, ISSN 0380-1330, DOI: 10.1016/S0380-1330(86)71724-3.
Pink salmon, Oncorhynchus gorbuscha, have adapted well to the Lake Superior environment and have become a significant member of the Great Lakes salmonid community. However, to properly manage pink salmon in this new environment, an improved understanding of their population characteristics is necessary. To gather population information, the following parameters were estimated for the 1981 and 1982 runs of pink salmon in the Cascade and Cross rivers, Minnesota: 1) absolute abundance of spawners, 2) age, size, and sex distribution of the spawners, 3) fecundity and growth of returning adults, and 4) egg deposition, egg fertilization rates, and embryo development. Trap nets were used to collect upstream migrant pink salmon, while electrofishing, carcass counts, and creel censuses were used to obtain recaptures. Left pectoral fin rays were used for aging and growth back-calculation. Redd samples were collected to estimate egg fertilization rates and embryo development. It was found that Lake Superior pink salmon are similar to their Pacific Coast counterparts, except that they are smaller and 3-year-old fish are common. The latter may preclude the genetic divergence based on spawning stock which is apparent in the Pacific. The sex distribution of 3-year-old pink salmon was highly skewed towards females. Three-year-old female pink salmon had a lower fecundity and a poorer egg quality than 2-year-old females. The major factor controlling the abundance of Lake Superior pink salmon appears to be limited spawning habitat.
Keywords: Fish populations; lake fisheries; fish establishment