Induction of Winter Breeding in Small Mammals by 6-MBOA

A plant-derived cyclic carbamate, 6-methoxybenzoxazolinone (6-MBOA), is known to initiate reproductive activity in Microtus montanus. We studied overwintering populations of four other rodent species, and observed increased reproduction in experimental populations of two herbivorous species, Microtus pennsylvanicus and Sigmodon hispidus, but not in two omnivorous species, Oryzomys palustris and Mus musculus. These results suggest that low concentrations of 6-MBOA may trigger seasonal breeding primarily in herbivorous small mammals

Small Mammals in the Great Dismal Swamp of Virginia and North Carolina

Small mammals were surveyed in a range of habitats in the Great Dismal Swamp of Virginia and North Carolina. The survey is based on three chronologically overlapping studies, each lasting 15-18 months and for which the results have been reported separately. A different trapping method was used in each of the three studies: nest boxes, Fitch live traps, or pitfall traps. Only two species of mammals, both arboreal, were taken in nest boxes, compared with 10 and 9 species in Fitch live traps and pitfall traps, respectively. The Fitch live traps had a much higher catch rate per 1,000 trap-nights than either of the other methods. However, pitfall traps were more efficient at catching Sorex longirostris fisheri and Synaptomys cooperi helaletes, two mammals that were previously believed to be rare. Although the catch rates were comparable in non forested habitats and in forest, more individuals and more species were obtained in the former. At least 5 of the 12 collected species do not occur in the forests. These studies added Sigmodon hispidus to the mammals known from the Dismal Swamp, and the results suggest that Peromyscus gossypinus no longer occurs in the swamp

Virginia\u27s Pfiesteria Monitoring Program: Water Quality

During the summer and early fall of 1998, 34 estuarine stations in Virginia were sampled for Pfiesteria like organisms (PLOs) and associated water quality conditions. Stations were sampled either bimonthly (20 stations) or monthly (14 stations) from June to October 1998. At each station, a set of live and Lugol\u27 s preserved samples were collected for presumptive counts of PLOs and water quality conditions were determined. Water quality parame­ters measured included standard field parameters, nutrients (total, dissolved, and particulate), chlorophyll a, and conventional water quality indicators. Although PLOs were relatively low in 1998 as compared to 1997, presump­tive PLO counts revealed higher PLO levels at stations located in the Northern Neck area (Potomac Embayments, Rappallannock River, and other smaller watersheds). The water quality parameters of pH, dissolved oxygen, and temperature were correlated with higher PLO counts, while several nutrients, salinity, and turbidity ,vere negatively correlated with PLOs. In the August 1997, relatively minor fish kills in the Pocomoke River and the Pocomoke Sound on the Virginia and Maryland border were attnbuted to the toxic dinoflagellate, Pfiesteria piscicida. Pfiesteria piscicida was first identified as a fish-killing dinoflagellate in fish tank at North Carolina State University (Noga et al., 1993 ). Pfiesteria piscicda has since been implicated in large widespread fish kills in North Carolina\u27s estuaries (Burkholder et al., 1992, 1995)