No abstract

Two dose confirmation studies are required by the U.S. Food and Drug Administration to verify the effectiveness of a candidate before approval as a new animal drug is awarded; the two studies provide independent substantiation of the results. This laboratory study was designed to compare an untreated control and a 10-mg/L copper sulfate (CuSO 4 ) treatment to control fungus (Saprolegnia spp.) on eggs of channel catfish Ictalurus punctatus at 23.58C in a flow-through system. The eggs were treated once daily until the embryos reached the eyed stage (five treatments). When hatching was complete for all viable eggs (day 10), the fry were counted to determine the percent survival in each treatment. Infestation by a fungus identified morphologically and by polymerase chain reaction as Saprolegnia spp. was severe in the control fish, resulting in 8% survival. The mean percent survival of fry hatched from the CuSO 4 -treated eggs was significantly higher (mean, 55%; range, 27-71%).

Numbers of Double-crested Cormorants (Phalacrocorax auritus) wintering in the southeastern United States have increased dramatically during the last 30 years concomitant with the rise of the aquaculture industry in this region. These cormorants commonly foraged at commercial aquaculture facilities and thereby came into conflict with farmers. Various interest groups are seeking ecologically sound strategies for minimizing the effects of burgeoning cormorant populations. Therefore, this study was conducted to estimate winter and summer home ranges of cormorants captured in the southeastern U.S. and determine whether age class, body mass, density of aquaculture facilities and availability of roost sites influenced size of these home ranges. Mean ± SE home range size and core use area of satellite transmitter-marked cormorants wintering in the southeastern U.S. from 1999 to 2001 were 17,490 ± 1,986 km 2 (N = 37) and 1,550 ± 265 km 2 (N = 37), respectively. Winter home range size was not affected by region, age class or body mass. Summer home range and core use area of marked cormorants was 30,547 ± 6,197 km 2 (N = 6) and 3,124 ± 1,019 km 2 (N = 6), respectively.