A NEW METHOD TO ESTIMATE EARLY HOLOCENE MEAN ANNUAL TEMPERATURE USING GROWTH CHARACTERISTICS OF FOSSIL PERCA FLAVESCENS (YELLOW PERCH)

One of the best preserved Early Holocene fossil assemblages ever reported comes from the 10,000 – 7,500 year-old Seibold site located in the Missouri Coteau, near Buchanan, North Dakota. The first fossils were recovered in 1971 and included spruce needles that were still green, complete skeletons of several types of fish surrounded by oily residues, and insects with gut and internal organs still preserved. The fossil fish recovered include complete specimens of yellow perch, which can provide insight into Early Holocene ambient temperature using our newly developed methodology. Ageable skeletons of fossil yellow perch, Perca flavescens (Teleostei: Percidae) were recovered from a lacustrine deposit to contrast the growth patterns between fossil and extant yellow perch, and these growth patterns were used to estimate the mean annual temperature (MAT) of the Early Holocene environment. Scales and vertebrae of yellow perch were aged by counting annuli. The age and total length of yellow perch provided information for a comparative analysis between that of Early Holocene and extant yellow perch. Total length and MAT data for 20 populations of extant yellow perch, ranging in latitude from the Central Manitoba, Canada to South Carolina, USA, were analyzed using linear regression analysis to develop a new MAT index. A preliminary examination of isolated fossil scales shows potential longevity of up to 16 years, a characteristic of slow growing yellow perch from cool climates. Our preliminary results also show that three fossil yellow perch skeletons, ages one to three years, recovered from latitude 47°N had total lengths-at-age values similar to that of contemporary yellow perch from the colder climate of central Manitoba (55°N). Using regression equation parameters and total length information from contemporary yellow perch, a MAT of approximately -0.1°C was calculated for the Early Holocene North Dakota environment. Comparatively, the current ambient MAT of the Seibold site is 4.5°C. Ultimately, these new techniques could be used at other localities containing yellow perch, for example those in Kansas, Minnesota, Oklahoma, and South Dakota and offer a new test for corroboration of palynological, oxygen isotope, and insect mutual climate range analyses for estimating the temperature of Quaternary paleoclimates.