| | Accession Number | 5004032 |
| | Title | Effects of some commercial fishing activities on eelgrass, Zostera marina, in New |
| | England: characterization of impacts and measurement of regrowth potential |
| | Project Description | Eelgrass (Zostera marina L.) is the dominant seagrass species of northern temperate coastal |
| | waters. In New England it forms extensive meadows in low intertidal and shallow subtidal areas of |
| | relatively low wave energy, where it contributes vital functions to the ecological integrity and |
| | economic value of coastal ecosystems. Various human-induced disturbances have contributed to |
| | declines in distribution and abundance of eelgrass in New England and elsewhere, with the direct |
| | effects of human activities emerging as a significant source of local habitat loss with the potential |
| | for large-scale cumulative impacts. Interest in effects of commercial fishing on eelgrass has |
| | intensified recently, due in large part to new federal and state policies acknowledging the critical |
| | dependence of healthy fish stocks on sustainable fish habitat. Implementation of policies to |
| | protect eelgrass from adverse affects of fishing is hampered by the paucity of scientific information |
| | on the extent of disturbance from commercial harvest operations and the recovery potential within |
| | impacted areas. The goals of this study are to characterize impacts of commercial fishing |
| | activities on eelgrass in New England and determine revegetation potential following disturbance. |
| | Our approach is to evaluate ongoing impacts within a representative estuary, Maquoit Bay, which |
| | is the northwestern boundary of Casco Bay, Maine. Hand digging of soft shell clams and bait |
| | worms occurs throughout the intertidal eelgrass beds, and mechanical dragging for blue mussels |
| | occurs in subtidal grass beds. Preliminary aerial and field observations reveal patches that have |
| | been denuded by fishing activities, ranging in size from a few square meters to up to 70 acres. |
| | Our specific objectives involve landscape- and population-level measures of harvest effects and |
| | revegetation patterns. We will (1) measure the extent of impacts of harvesting activites in Maquoit |
| | Bay with metric quality aerial photography and bottom profiling equipment, and use a geographic |
| | information system to compare eelgrass distribution to historic records; 2) determine the local |
| | intensity of impacts of harvesting activities on eelgrass by comparing plant and sediment |
| | characteristics between impacted and undisturbed sites; (3) document patterns of revegetation |
| | using low altitude aerial photography; (4) quantify rate of eelgrass regrowth from edges of |
| | disturbed patches by measuring rate of eelgrass rhizome elongation, and use this information to |
| | predict recovery time; and (5) compare eelgrass characteristics within patches along temporal |
| | gradients of disturbance to provide additional estimates of bed recovery time. Finally, we will |
| | compare predicted recovery rates from Maquoit Bay with concurrent measurements of |
| | revegetation at eelgrass restoration sites in the Piscataqua River, Maine-New Hampshire border, |
| | to ensure broad geographic applicability, as these sites have previously been related to other |
| | eelgrass beds in New England. |
| | Keywords | commercial fishing, disturbance, eelgrass, seagrass, zostera marina, |
| | Principal | Hilary A Neckles, USGS Patuxent Wildlife Research Center: hilary_neckles@usgs.gov; Seth |
| | Investigators | Barker, Maine Department of Marine Resources: seth.barker@state.me.us; Frederick T Short, |
| | University of New Hampshire: fred.short@unh.edu; |
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