Age, growth, mortality, and distribution of pinfish (Lagodon rhomboides) in Tampa Bay and adjacent Gulf of Mexico waters

Life-history dynamics of pinfish (Lagodon rhomboides) were examined from data derived from random station surveys conducted in Tampa Bay and adjacent Gulf of Mexico waters during 1993–97. In addition, patterns in spatial distribution and abundance in Gulf of Mexico waters were investigated. Ages determined from whole otoliths ranged from 0 to 7 years, and von Bertalanffy growth models for males and females were not significantly different. Von Bertalanffy growth model parameters were L∞=219.9 mm SL, k =0.33/yr, and t0 =–1.10 years for all fish combined. High gonadosomatic indices during October–December indicated that some spawning may occur in Tampa Bay. Estimated lengths at 50% maturity were 132 mm SL for males and 131 mm SL for females. Total instantaneous mortality rates derived from the Chapman-Robson estimator ranged from 0.88 to 1.08/yr, and natural mortality was estimated to be 0.78/yr. In Gulf of Mexico waters, pinfish catch rates declined with increasing depth, and most pinfish were caught in <17 m of water. Length distributions showed that pinfish segregate by size with increasing depth.

Centennial oscillation of the climatic crescendo during the last glacial maximum: evidence from Lake Estancia, central New Mexico

Sediments deposited in late Pleistocene Lake Estancia, central New Mexico, contain a paleoclimatic record that includes the last glacial maximum and deglacial episode. Stratigraphic reconstruction of an interval representing the highstand of the lake that occurred during the last glacial maximum reveals ~2000-, ~600-, and ~200-year oscillations in lake level and climate. Shifting position of the polar jetstream in response to expansion and contraction of the North American ice sheet may be partly responsible for the millenial-scale changes in Lake Estancia but probably does not explain the centennial-scale oscillations.