If anyone was expecting clarity from yet another review of harbor seal behavior and oyster farming at Point Reyes National Seashore, it wasn't forthcoming, as the report qualifies many of its conclusions and calls for yet more research.

While the Marine Mammal Commission, a federal agency, found that seal behavior at Drakes Estero in the national seashore was "at least correlated" with operations of the Drakes Bay Oyster Co., it also said more research is needed to determine a "cause and effect."

Perhaps more importantly, the 70-page report said there's no solid evidence as to how disturbances to the seals affects them biologically.

Data supporting a direct connection between the oyster company's operations and seal behavior "are scant and have been stretched to their limit," the commission's report said. And yet, a 2011 study by the National Park Service provides "some support for the conclusion that harbor seal habitat-use patterns and mariculture activities in Drakes Estero are at least correlated."

"However," the report issued Tuesday goes on, "the data and analyses are not sufficient to demonstrate a causal relationship. Additional, carefully guided study would be required to determine if the apparent relationship is one of cause and effect."

The battle over the future of the oyster company has been ongoing for a number of years. When the company's owner, Kevin Lunny, bought the operation from the Johnson Oyster Co. in 2005, it came with a 40-year lease that expires in November 2012. And since the oyster farm is located in an area of the seashore, Drakes Estero, that has been targeted for official wilderness designation, his ability to gain a lease extension has been impeded.

At issue is whether the oyster farm is adversely impacting Drakes Estero and its marinelife, particularly harbor seals. The estero long has been viewed for designation as official wilderness -- the 1976 legislation that set aside 25,370 acres of the seashore as wilderness cited another 8,003 acres that would be "essentially managed as wilderness, to the extent possible, with efforts to steadily continue to remove all obstacles to the eventual conversion of these lands and waters to wilderness status" -- and the oyster operation is seen as being incompatible with such a designation.

The Park Service's handling of the oyster company's future has been both contentious and embarassing for the agency. While a Park Service report on the oyster operation concluded that it was impacting harbor seals, the report at times has withered under scrutiny. In 2009 the National Research Council said the NPS report was skewed, "selectively" manipulated in several areas, and inconclusive overall.

A year later, the Interior's Solicitor's Office conducted an investigation into whether the staff at Point Reyes had intentionally mishandled research data it collected to determine the oyster farm's impacts, if any, on harbor seals during pupping season. That probe cleared the staff of any criminal behavior or criminal misconduct in the matter, a finding that itself has drawn criticism.

Part of the investigation centered around charges that Park Service staff "suppressed" more than 250,000 photographs the Point Reyes staff captured with a secret camera from 2007 to 2010 to determine whether farm operations were disturbing harbor seals during the pupping season.

Those photos, proponents of the oyster farm say, failed to show any disturbance of harbor seals by farm employees. Interviews conducted by the Solicitor's Office, however, indicated that on at least five occasions the farm's workers caused disturbances of seals during pupping season.

The Marine Mammal Commisson's report draws into question those photographs, saying further review is necessary "to assess their usefulness for characterizing the rates and consequences of (seal) disturbance."

"Also, studies are needed to characterize harbor seal haulout patterns in the absence of disturbance, and to assess the biological significance of disturbance when it occurs," the report added.

The commission pointed to a number of problems with previous studies into the oyster company's operations and seal behavoir, ranging from insufficient data pertaining to what exactly disturbs the seals and how significant the disturbances are and incomplete notes by observers to a lack of evaluation into the seals' "haulout patterns and habitat uses and needs of harbor seals within the estuary."

"These (haulout patterns and habitat uses) data are needed to determine whether the measures in the 1992 agreement are or are not effective and sufficient and whether the protection zone established by the California Coastal Commission is or is not needed," the commission noted.

More so, the agency pointed out, there's a lack of information specific to how disturbances affect the seals.

"The tolerance of seals for disturbance and the biological significance of such disturbance should be evaluated. At present, indicators of disturbance are defined as ranging from head alerts to flushing into the water. The existing information is not sufficient to describe the biological consequences or reactions at either end of this continuum," it said.

Also important is knowing how other human activities in the seashore affect the seals, the commission said.

"Hikers, kayakers, horseback riders, aircraft, and other sources also may be affecting the seals and those effects may increase as human populations grow and use of the Point Reyes National Seashore increases. Understanding the effects of these other activities is required to assess the combined impacts of human activities on harbor seals and their use of the estuary."

While the national seashore has completed a draft environmental impact statement examining the oyster company's impact on the harbor seals, it has not identified a preferred alternative. Ultimately, the company's fate is in the hands of Interior Secretary Ken Salazar.

"If the Secretary determines that the estuary should be converted to full wilderness status, then the Park Service should continue to study the seals to determine if and how they may change in abundance or alter their habitat-use patterns," the commission's report said.

"If the Secretary decides to renew the Reservation of Use and Occupancy and a Special Use Permit issued to Drakes Bay Oyster Company, then the Commission believes that he also should require the Park Service to implement an adaptive management approach that, if done well, should address the various weaknesses and gaps in the available data."