A decrease in large clams is also evident. Mr. LaPan also said the attachment of the mussels may hinder the mobility of clams. Impact of a loss of clams has not been determined yet. Mr. LaPan doesn't believe their loss will have a direct impact on the fish system, but parasites and grubs that clams harbor and muskrats that feed on clams may be affected. Mr. LaPan is also concerned about the loss of rare clams living in Lake Ontario.
Fish seem to have adapted to the presence of zebra mussels.
Sturgeon and drum or sheephead fish now feed on the mussels, which are plentiful and have shells that are easy to crush. Fisherman at the St. Lawrence fisheries meeting on July 18 said they noted that perch also seem to eat the mussels. Mr. LaPan believes perch are more likely to eat them by accident, when the mussels are attached to zooplankton they are feeding on. Bass populations are increasing in Oneida Lake, where Mr. Mills researches, because clear water encourages aquatic plant growth. Circopagis, the fish hook flea, introduced in 1998, is becoming prolific and will likely be a nuisance this spring.