No danger of invasive species from oil rig, biologist says

Buccaneer Energy paid for private survey after shell was found.

Peninsula ClarionSeptember 24, 2012 

KENAI -- A biologist hired by Buccaneer Energy has determined that any invasive shells and organic marine debris attached to the company's Endeavour-Spirit of Independence drilling rig did not survive the trip from Singapore to Kachemak Bay.

In a report released to the Peninsula Clarion last week, David Erikson, senior biologist with URS Corp., concluded that the Endeavour's time in dry dock and aboard a transport ship for its month-long trip was largely responsible for killing the attached marine organisms, thus "substantially reducing the potential for any non-indigenous or invasive species" to be introduced into Kachemak Bay, where the rig is currently parked.

Alaska Department of Fish and Game officials talked with Buccaneer two weeks ago about what organisms might still have been attached to the rig when it was brought from Singapore after a Homer resident plucked a small shell from one of the rig's legs during a tour.

The resident, Larry Smith, said the shell appeared to be a foreign oyster -- "one of thousands" in the area where he found it. The discovery prompted Fish and Game's invasive species program to offer Buccaneer a survey of any organisms still on the rig. Buccaneer instead hired Erikson to do a survey on Sept. 10 and 11.

It's against the law to "knowingly introduce" an invasive species to Alaska, specifically "fish, invertebrates and amphibians," said Tammy Davis, a Juneau-based Fish and Game biologist who leads the department's invasive species program.

In general, jack-up rigs provide "an excellent hard substrate for encrusting marine invertebrates and algae to attach to," and some marine growth on a rig's large leg structures is to be expected, Erikson wrote in his report. For that reason, rig legs need periodic maintenance and cleaning to reduce the potential of introducing invasive species.

"From the size of the shells, the attached oyster shells appeared to be from mature specimens at least a couple of years old," Erikson wrote. "The number of species of oysters or barnacles present on the rig and their age was not determined."

Ginny Litchfield, area manager of Fish and Game's habitat division, said the department has received the report and is reviewing it.

"ADF&G will review all pertinent information prior to determining course of action or possible follow-up," she wrote.

The first day of Erikson's survey, he wrote, focused on the rig's three legs, particularly the portions near the waterline or that were in the water during the period when the rig was "cold-stacked." Erikson took photographs and collected samples of shells from the rig's leg, deck and walkways.

The second day of the survey focused on the bottoms of the legs and the supporting members.

"These areas had not been recently scraped and painted like the rest of the legs and marine growth was evident," Erikson wrote.

Photos and samples of encrusted marine life were taken for microscope analysis.

Shells found on the rig were primarily confined to a 4-inch space between the legs and the "jacking guide," Erikson reported. Most of the shells were covered with a thin coat of gray paint and were determined to be primarily oyster shells and barnacles, he wrote.

None of the shells examined supported any live animals or contained remnant tissue, Erikson wrote. Some shells had started to deteriorate, he added.

Erikson recommended Buccaneer remove loose shell debris from all areas at once to minimize the risk of invasive species, clean and monitor a gap near the jacking guides and clean marine organisms from the legs after the completion of drilling each year.

Anchorage Daily News is pleased to provide this opportunity to share information, experiences and observations about what's in the news. Some of the comments may be reprinted elsewhere in the site or in the newspaper. We encourage lively, open debate on the issues of the day, and ask that you refrain from profanity, hate speech, personal comments and remarks that are off point. Thank you for taking the time to offer your thoughts.

Commenting FAQs | Terms of Service