A subsidiary of Petrohawk Energy Corp. has been fined $350,000 and ordered to pay an additional $150,000 in restitution for damaging the habitat of an endangered species in Arkansas. The latter amount will be paid to the National Fish and Wildlife Foundation for use in watershed restoration projects in the area, according to a press release from the U.S. Attorney's Office.

The damage was caused in three forks of the Little Red River, home to the critically endangered speckled pocketbook mussel (Lampsilis streckeri). It is unknown exactly how many of the freshwater mussels were affected by the damage to their habitat.

According to the International Union for Conservation of Nature and Natural Resources (IUCN), the upper Little Red River in the Ozark Mountains is the only habitat of the rare bivalve.

Petrohawk subsidiary Hawk Field Services, LLC, pleaded guilty to three counts of violating the Endangered Species Act on April 8. Sentencing took place on September 14.

"This sentence should serve notice to all companies who would threaten our natural resources that we will prosecute those who carelessly conduct business to the detriment of our state's resources," U.S. Attorney for the Eastern District of Arkansas Christopher R. Thyer said in the prepared statement. He noted the health of the speckled pocketbook mussel is an important indicator of the water quality in the Little Red River, because it depends on clean water.

According to the U.S. Attorney's Office, Hawk Field Services did not adequately control erosion during the construction of a natural gas pipeline in the nearby Fayetteville Shale, allowing silt to run downhill into the river, where it built up as sediment, affecting water quality in the mussels' habitat. The construction project lasted from October 2008 to April 2009.

Petrohawk sold its natural gas assets in the Fayetteville Shale to a subsidiary of ExxonMobil in 2010. Petrohawk itself was recently acquired by Australia's BHP Brilliton, Ltd. None of the companies have released a statement about the case or the fine.

Photo by Chad Cooper via Flickr. Used under Creative Commons license