Habitats in the Bays

MassBays estuaries are complex

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Eelgrass is a flowering marine plant that typically grows in shallow, protected estuaries, forming underwater “meadows.” Eelgrass meadows protect sea creatures like fish and lobsters when they are young and while they lay eggs, and also provide food. With their extensive root systems, eelgrass meadows stabilize the sea bottom and reduce erosion. Like other plants, eelgrass generates energy through photosynthesis, producing oxygen and storing carbon. They also improve water quality as the leaves absorb some pollutants and excess nutrients, and cause fine sediment to settle out of the water. 

In MassBays’ study area, our XX acres of eelgrass (per the latest sequence of mapping, completed in 2017) are threatened by dredging, pollution from stormwater runoff and wastewater, and even boat moorings. 

Diadromous, or migratory fish, either begin life in freshwater and spend the majority of their life in the ocean, returning to freshwater only to spawn and lay eggs (herring, smelt, shad, brook trout, and sturgeon, for example) or do the opposite – starting their life in the ocean and spending most of their life in freshwater, then returning to the ocean to spawn (for example, American eel). Habitat for Diadromous fish includes the streams they rely on for migration, as well as the areas in which they live and spawn.

Most migratory fish become food for larger fish and other wildlife, playing a key role in the food web both at sea and inshore. Historically, river herring especially were a core component of indigenous peoples’ diet; currently, only state- and federally recognized tribal members are allowed to harvest them, to preserve the remaining population.

MassBays’ study area includes XX miles of streams for migration, and XX ponds known to shelter diadromous fish. Threats to these resources are varied: physical barriers like dams, tide gates and culverts restrict passage and water flow; broken fish ladders also block migration, and some make migrating fish easier targets for predators. Dredging and development close to riverbanks often degrade spawning and nursery areas, while stormwater runoff and wastewater discharges introduce pollution.