New Hampshire Estuaries Project’s (NHEP’s) Technical Advisory Committee (TAC) developed a suite of environmental indicators to track progress toward the NHEP’s management goals and objectives in 2001–2002. The indicators were described in terms of their performance criteria, statistical methods, and measurable goals in NHEP’s monitoring plan.
Indicators of critical species and habitats discussed in the report are eelgrass distribution, abundance of juvenile finfish, anadromous fish returns, lobster abundance, and abundance of wintering waterfowl. These indicators all were supporting variables that were not used to answer management questions, thus no management goals were set.
- Eelgrass (Zostera marina) distribution: NHEP monitors eelgrass in the tidal tributary of Great Bay, Great Bay, and Little Bay. Eelgrass is an essential habitat for estuaries because it provides food for wintering waterfowl and habitat for juvenile fish. Eelgrass can provide input about the state of water quality (e.g., water clarity); however, other factors also can affect the health of eelgrass. For example, in 1989, there was a significant decline of eelgrass beds (a decrease to 15 percent of original levels) caused by a slime mold infestation.
- Abundance of juvenile finfish: NHEP monitors juvenile finfish to analyze year-to-year trends in abundance and diversity. Juveniles make good indicators because they are sensitive to estuarine conditions—they occupy the lower end of the food chain and their dynamics are less complicated. They spend significant portions of their life history in the estuary and are an important source of food.
- Anadromous fish returns: Abundance was compiled of five anadromous fish species—herring, shad, salmon, rainbow smelt, and lamprey. The TAC considered these species as indicative of conditions in the upper watershed. The adults need passage through dams and suitable upstream habitat to spawn. Although changes in anadromous fish returns could be the result of many factors, tracking the returns would be a useful indicator of ecological conditions, as long as consideration is given to factors such as the efficiency of fish ladders, quality of spawning habitat, predation levels, harvest pressure, and stock enhancement. The objective is to illustrate year-to-year trends in the abundance of anadromous finfish in the estuary.
- Lobster abundance: Commercial fishery for lobster is the largest and most important fishery in New Hampshire. Although lobsters are not exclusively dependent on conditions in the estuary to survive, a crash in the lobster population would be a cause for concern both ecologically and commercially. The objective of this supporting variable is to track the overall abundance of lobsters (total and legal size) to illustrate any trends over time.
- Wintering waterfowl abundance: 75 percent of wintering waterfowl come to Great Bay or Hampton Harbor. Salt marshes and tidal flats are the most important types of wetlands for these species—eelgrass and tidal flats provide winter forage. Although multiple factors affect the abundance of wintering waterfowl, tracking their abundance would help illustrate changes over time.
The NHEP TAC also set environmental indicators of habitat restoration:
- Restored salt marsh—The NHEP goal is to restore 300 acres of salt marsh by 2010. This indicator was set to track the cumulative acres of restored saltmarshes and directly shows progress of one of the management objectives set by NHEP.
- Restored eelgrass beds—The NHEP goal is to restore 50 acres of eelgrass beds by 2010. This indicator allows NHEP to track restored cumulative acres of restored eelgrass beds and directly shows progress of one of the management objectives set by NHEP.
- Restored oyster beds—The NHEP goal is to restore 20 acres of oyster habitat in Great Bay and tidal tributaries. This indicator allows NHEP to track restored cumulative acres of restored oyster beds and directly shows progress of one of the management objectives set by NHEP (Trowbridge 2003).
Reference:
Trowbridge, P. 2003. New Hampshire Estuaries Project – Environmental Indicator Report: Species and Habitats. Prepared for New Hampshire Estuaries Project. Accessed October 2016.