Restoring Ecological Functions and Increasing Community Awareness of an Urban Tidal Pond Using Blue Mussels

Abstract

Blue mussels (Mytilus edulis) were transplanted into South Mill Pond, a degraded tidal salt pond in Portsmouth NH. As part of a larger community-based project volunteers helped create three mussel reefs in each of two locations within the pond in May 2001. Restoration project methodology and success were evaluated during the summer of 2001 and again in May 2002 by 1) assessing reef population dynamics (size frequency distribution, density, and movement) and 2) comparing faunal utilization (finfish species and abundance) within the reefs to that in adjacent reference areas. Created reefs showed declines in density after the first month but then increased and showed new recruitment the following year. Reef footprints were dynamic and probably influenced by mussel density as well as local hydrology. Four finfish species were observed: Atlantic silverside (Menidia menidia), mummichog (Fundulus heteroclitus), four-spined stickleback (Apeltes quadracus), and three-spined stickleback (Gasterosteus aculeatus). The most common fish in reef and reference areas (silverside and mummichog, respectively) are highly mobile species. Reef areas had greater species diversity per sampling effort than reference areas, but no difference in overall fish abundance was found between adjacent reef and reference areas. Information collected to date indicates that mussel reefs constructed at the pond appear to be functioning as a natural system, acting to improve water quality and provide shelter for small fish and other nektonic and epibenthic invertebrates. In addition, volunteer action garnered city involvement and increased local awareness of the pond as an ecosystem rather than a sewage lagoon. Community awareness along with habitat improvements will increase the long-term prospects for rehabilitation of South Mill Pond.