Ecology Briefs

Va. bans blue crab dredging in Chesapeake Bay for winter

Citing the need to replenish low numbers in the Chesapeake Bay, the Virginia Marine Resources Commission has approved a ban this winter on dredging blue crab, according to a report from the Associated Press. This is the commission's first ban since 2008, when the number of adult crabs was around 131 million.

Although that number has since risen to 254 million, assessments by scientists recommend that the crab population needs to be raised to 415 million with 215 million female crabs in order for the crab populations to be sustainable. The commission also notes that female crabs also take the greatest hit during winter dredging, when blue crabs are typically hibernating at the bottom of the bay. Blue crabs also coalesce in the southern part of the bay during the winter.

Nitrate rising in northwest Pacific, impacts marine life

American and Korean researchers from Penn State and Korean institutions have found increased levels of nitrate affect the balance of nutrients and wildlife off the coast of Japan and Korea. Examining the effects of river runoff and atmospheric pollution, as well as industrial and agricultural sources of nitrogen since the 1980s, the group has found that the abundance of nitrogen shifts a balance between its levels and aquatic levels of phosphorus. This change can create a new environment that favors plants that can thrive in these conditions.

Increases in nitrate levels from human activity have been examined thoroughly in freshwater and smaller bodies of water. The study is the first to find evidence of the impact of nitrate levels on larger, more open bodies of water. Their results are published this month in the journal Science.

Foreign species of reptiles and amphibians settle well in Fl.

A 20-year long study of non-native reptile and amphibian species in Florida found that about 56 invasive species have successfully established themselves, thanks in part to humans and the temperate climate. Invasive species present a threat to other native species, especially those that are endangered, as well as a hazard to humans.

Historically many of these species arrived aboard cargo ships beginning in the 1800s, but since the 1970s some more exotic and hazardous species were brought in by the pet trade. Their study attributes to the pet trade about 84 percent of new species introduction. One of the most prominent, the Burmese python, is but one of six python species that present a significant danger to both local wildlife and humans.