Meeting Abstract

P1.21  Tuesday, Jan. 4  Gill Morphology and Oxygen Diffusion Distance in Juvenile Striped Killifish MCENROE, M*; RIVERA, L; LA FORTUNE, B; MILLER, A; FOROSTYAN, T; Purchase College, SUNY; Purchase College, SUNY; Purchase College, SUNY; Purchase College, SUNY maryann.mcenroe@purchase.edu

Larval and juvenile striped Killifish (Fundulus majalis ) inhabit shallow marsh pools which become warm and oxygen-limited in summer. To investigate potential physiological and morphological adaptations of killifish to this environment we studied gill morphology. As shown by Fick’s equation for diffusion, gill surface area (GSA) and oxygen diffusion distance are important parameters for oxygen uptake at the gills. To measure these parameters fish were collected from Long Island Sound and from marsh pools in late summer, weighed, measured and the gills were fixed in Karnovsky’s solution. For scanning electron microscopy (SEM) they were rinsed, dehydrated in a graded ETOH series, and critically point dried, sputter-coated and were observed with ISR-SR-50 SEM. Gill morphology (number of filaments, filament length, lamellar density and lamellar size) was quantified using the methods of Hughes (1966, 1984). To measure oxygen diffusion distance from water to blood, samples were embedded in Araldite 502/Embed 812 TM plastic medium for transmission electron microscopy (TEM). Stained (uranyl acetate and calcinated lead citrate) thin sections were examined using a FEI/Philips Morgagni 268 transmission electron microscope (TEM). Gill lamellar diffusion distance was measured using the technique of Matey et al., 2008. Gill structure and oxygen diffusion distance will be compared to other fishes.