Comparative Energetics of Two Populations of the Unionid, Anodonta cataracta (Say)

Anodonta cataracta from Layton's Lake are more abundant (24.3/m2), have a substantially higher rate of tissue weight accumulation and lower rates of respiration, filtration and fecal production than individuals from Morice Lake (3.9/m2). Seston concentrations are only slightly higher in Layton's Lake but concentrations of suspended organic carbon do not differ. In spite of higher seston densities, the lower filtration rate of Layton's Lake Anodonta resulted in a lower potential clearance of particles. Possible explanations for the differences in energetics of the two populations are discussed.