Well, it might.

The state recently identified the ponds as potential habitats for two endangered species of mussel — the Eastern Pond Mussel [top right] and the Tidewater Mucket [bottom right] — and is requiring the Pembroke Watershed Association to complete a study to determine whether the bottom-dwelling invertebrates actually do make their homes in Oldham and Furnace ponds.

If the mussels are found, the company hired to manage the algae on the ponds may have to adjust its treatment plan to ensure the proposed copper sulfate injections don't harm the endangered mussels.

Either way, it doesn't look like the algae cleanup will begin this summer.

"I think treatment in all reality is probably not going to happen this year," said Keith Gazaille, senior biologist with Aquatic Control Technology Inc. "It'll probably take the better part of this season to complete this process and get everything squared away so that we'll have permits for the next year."

After discussing the hitch in their treatment plan at a meeting on Thursday, July 23, the Watershed Association voted to pay for the mussel study and agreed to delay treatment until next summer.

PWA president Ray Holman said the $12,660 approved for the project at Town Meeting would be carried over to next year, per town warrant rules, but he was unsure whether Hanson's contribution of $4,000 could be held until next year as well.

Funding only covered treatment on Oldham Pond, but the Watershed Association voted at their June meeting to allot $5,150 from their reserves to treat Furnace Pond this summer as well. Now both projects are on hold according to a directive from the Natural Heritage and Endangered Species Program, which identified the two mussel species as potentially living in the ponds.

Gazaille said he had contacted the two qualified mussel biologists he knew of in the state. One responded with a cost estimate of about $4,800 for the study, which involves diving to the bottom of the ponds to look for the mussels. The second had not returned an estimate as of last week.

The study will take longer than usual because algae has caused visibility problems, Gazaille said.

"The best-case scenario for us in terms of moving forward with the program is the species are no longer found living in the pond, which is a real possibility. A lot of these Natural Heritage records date back as much as 100 years," Gazaille said. "I think then we would be able to move forward in the permitting process."

If either mussel is found in the ponds, the company will work with Natural Heritage to determine the best way to proceed. Gazaille said some research has shown that copper treatments could harm certain invertebrates and that the company might have to adjust the level or regularity of doses.

Hearings with both towns' Conservation Commissions have been continued until the end of August to allow the study to be done.

Also last Thursday, Gazaille and PWA member Bill Glover discussed hydrilla management on Hobomock Pond, which has been closed since the fall to prevent the spread of the aquatic plant. The Watershed Association also hired Aquatic Control Technology to manage that project. The company delivered the first dose of SONAR, an algaecide designed to slowly kill the plant by working through its entire system, on June 5.

Gazaille said workers planned to deliver a second dose last Friday.

Glover, who notified the state after discovering the hydrilla last summer, said he already has seen an improvement. "I've been going down and kind of monitoring to see how this treatment is working," he said. "I can honestly say this pond is looking cleaner than I've seen it in the last two or three years."

Glover said the pond has lost its "green hue" and that a lot of the plants have floated to the surface and appeared "bleached out." Some PWA members questioned whether they should remove the apparently dead material.

Gazaille said residents should leave the plants alone to allow the herbicide to completely work its way through and ensure they would not sprout again next season.

The pond remains closed indefinitely. Both Oldham and Furnace ponds are open to recreational use.