Annisquam River Marsh: Introduction

“The men folks... would go on a fishing excursion out in the bay, or after berries in the West Gloucester woods, finding time between whiles to extricate from their sandy beds a bountiful supply of succulent bivalves, commonly known as clams, which were served up as most toothsome viands; boiled, or fried, or the most delectable chowder… nearly 40 years have passed since those days of the early campers. The waters of the old Annisquam River still ebb and flow.” —Tribute to James L. Shute by Mary Palmstrom, 1909 Camper on Merchant's (Pearce) Island¹

This case study explores Cape Ann's Marsh Landscapes through the West Annisquam River Marsh site. The analysis is informed by existing reports and resources that have been written to describe and understand the West Annisquam River.

The research consists of an analysis of Annisquam's habitats as interconnected systems, a list of existing species, and an exploration of the landscape's changes over time.

The analysis informs the recommendations made in the next section, Marsh Scenario Plans.

Habitats

“Restoration efforts are benchmarked, given success metrics that often borrow from a wilderness conservation mindset. A pre-colonization (often mistaken for pre-human) population is a typical goal. Dana, though, expects the oysters to become a sort of ecological infrastructure. She cares little for achieving a mythic landscape of the past and instead is focusing on attracting a self-sustaining oyster population. She is restoring the future ecology of the Annisquam.” —David Morgan, 2019, Multispecies Urban Planner²

Annisquam Ecosystem Composition

The Annisquam Ecosystem is comprised of different terrestrial, estuarine, and marine habitats. Each of these habitats hosts flora and fauna that have evolved to survive in these environments. These descriptions are elaborated in an overview of existing literature along the Annisquam River in the subsection, Changes.

This subsection explores the Annisquam's habitats as individual components, noting their dominant species and the percentage of the area they occupy. While this analysis is beneficial, it is important to remember that the Annisquam's habitats are interconnected and impact one another. For example, while some specialist species, like the Saltmarsh Sparrow (Ammospiza caudacuta), may spend their entire life cycle in a single habitat, other species, like alewive fish (Alosa pseudoharengus), move across different habitats at different life stages.

 

Marshes have zones of vegetation based on elevation and saltwater inundation. Saltmarshes are one of the most biologically productive ecosystems on the planet and the base of the marine ecosystem largely as a result of cordgrass growth and decomposition.

Low Marsh: 13.3%

Saltmarshes are one of the most biologically productive ecosystems on the planet, due to the amount of detritus that is produced by cordgrasses. Marshes have zones of vegetation based on elevation and saltwater inundation. Low marsh areas are regularly inundated. Low marsh areas are dominated by smooth cordgrass (Spartina alterniflora), a tall species that grows from the spring until autumn before going dormant during the winter months. Bacteria decompose dead cordgrass, which are then consumed again by bacteria and fungi, and then reconsumed by worms, crustaceans, mollusks, insects, and other fish. Saltmarshes, therefore, are the base of the marine ecosystem.³ Raptors hunt throughout low marsh areas, as they are attracted to the smaller organisms in the marsh. As sea-levels rise, low marsh is observed transitioning to pannes and mudflats. Mudflats reflect a loss of marsh habitat, which degrade into non-vegetated areas. The agricultural and mosquito ditches dug into the marsh as part of colonial saltmarsh haying operations and New Deal work programs further degrade the marsh system by changing water flow and sedimentation patterns, and quickening the rate of erosion.

 

High Marsh: 13.4%

High marsh areas are dominated by saltmarsh hay (Spartina patens), the backbone of the colonial agricultural economy. In high marsh areas, the accretion of dead grasses rapidly accumulates to form peat banks. The borders of high marsh areas are host to invasive Phragmites in areas with limited saltwater flow due to tidal obstructions, including culverts. High marsh is home to critical bird species including Saltmarsh Sparrows, which are obligate species, meaning they breed and feed in saltmarsh habitats.

As sea levels rise, high marsh is observed transitioning to low marsh that is more frequently inundated. Conversions from high marsh to low marsh will reduce high marsh habitat to just thirty-six acres across all of Gloucester by 2070. The eradication of high marsh along the Annisquam will contribute to the extinction of the obligate Saltmarsh Sparrow, and harm other wetland dependent bird species.⁴

Tidal Flats: 22.4%

The tidal flats along the Annisquam provide habitat for soft-shelled clams, which grow a few inches above the spring low-water line to the top of sand bars. Individual and commercial shellfishermen pick out the clams, which are sold to local seafood restaurants when the beds are open. Water quality issues along the Jones, Little, and Mill Rivers close the beds at certain times throughout the year, and some areas near marinas and development always prohibit shellfish harvesting.

 

Estuary: 8.4%

The Annisquam is tidal-influenced. Marine saltwater conditions dominate to its high tide limits, though freshwater flows into the River from the Little and Mill Rivers. Tidal flow has been restored to the Upper Mill River through a tide-gate, and marine shellfish have begun to grow along its banks. Throughout the Annisquam, plankton are suspended in the water column along the River, where they consume organic matter and debris, which is also found buried in the sand and mud along the channels. The substrate conditions along the estuary vary, and provide habitat for different communities of benthic organisms, from soft-shell clams in sandy tidal flats and oysters in rocky areas. Alewives, American eels, winter flounder, and silver hake, among other fish species, are found in the Annisquam at different times of year. Invasive European green crabs compete for habitat with Jonah crabs throughout the Annisquam, and serve as prey for Great Egrets, Green Herons, and Black-crowned Night Herons.

The River is dredged by the US Army Corps of Engineers to maintain an eight-foot-deep navigable channel at Mean Lower Low Water. Dredging maintenance is performed as sediments shift over time in currents, making navigation through the Annisquam hazardous during lower tides. Dredging disturbs habitat for fish and shellfish, highlighting just one of the many challenges in balancing the Annisquam for commerce, recreation, and habitat.

 

Freshwater: 1.8%

Every spring, volunteers take ten minute shifts counting alewives at the Little River fish ladder as they travel upstream through to Lily Pond to spawn. Alewives are anadromous, meaning they migrate from the sea to freshwater rivers to spawn. American eels take a different journey. They are a catadromous species, so they live their lives in freshwater, and travel to the ocean to spawn. These species illustrate the critical linkages between freshwater and saltwater in the Annisquam.
 
 

Scrub and Shrubland: 1.0%

The border of saltmarsh lands includes transitional scrub and shrubland, including species like saltmarsh elder, sea lavender, and false foxglove. Transitional vegetation that is not inundated by salt water includes cattails (Typha sp.) in inland areas as well as marginal woody vegetation like staghorn sumac (Rhus typhina).

As high marsh areas transition to low marsh areas, these species, which cannot tolerate brackish conditions, will be threatened. Phragmites, which tolerates low salinity, will increase in these areas.

 

Maritime Forest: 31.2%

Coastal trees endure salt spray, high winds, periodic storm surge that splashes inland, and blowing sediment. These environmental conditions can exacerbate erosion, expose root systems, and create flagging branches as plants are exposed to significant stressors. Despite these challenges, deciduous trees, including red maples and white oaks, grow on the islands throughout the Annisquam, and on the upland areas on the banks of the estuary. Eastern red cedar (Juniperus virginiana) also grows on the fringes, along with paperbark birch. Mid-story shrubs, including bearberry (Arcostaphylos uva-ursi) and beach rose (Rosa rugosa) also inhabit this environment, and provide berries and rose hips for fauna. Vines, including poison ivy (Toxicodendron radicans) and Virginia creeper (Parthenocissus quinquefolia) take root on the ground and wind their way up through the canopy.

 

Impervious Surfaces: 7.6%

Roadways, parking lots, causeways, roofs, and patios are all examples of impervious surfaces. These surfaces border the Annisquam in developed areas, and also cross the Annisquam. Route 128, the MBTA drawbridge, and causeways like Long Wharf alter drainage patterns in the River. Impervious surfaces do not allow water to drain into the soil. These surfaces also transport stormwater runoff, including chemicals, pesticides, and other pollutants, into the Annisquam River, and into the Atlantic Ocean.

 

Ocean

The Annisquam is part of the Gulf of Maine, a semi-enclosed body of water that connects Cape Ann to the global ocean. The Gulf of Maine is a cold body of water. The average water temperature during the coldest month, March, is 39.6°F. In August, the warmest month, the average water temperature is just 66.9°F.⁵ The tidal range is eight and a half feet on average throughout the year. Ocean water enters the Annisquam from Gloucester Harbor to the south and Ipswich Bay to the north, though currents create a dominant water flow north through the River. Since the 1600s when the Cut Bridge was dug, the Annisquam has provided a shortcut for fishing and recreational watercraft to avoid navigating around East Gloucester and Rockport. The Annisquam provides a nursery for the recreational fishing grounds in Gloucester Harbor, and commercial fisheries beyond. Eelgrass, a sea grass that sequesters carbon and provides nursery habitat for fish, crabs, and shrimp, grows at the northern mouth to the Annisquam. The pelagic community along the Annisquam is similar to Ipswich Bay, including mackerel, herring, pipefish, pollack, alewife, silver hake, common squid, and jellyfish. Common Terns, Belted Kingfishers, Herring Gulls, Great Cormorants, and Osprey dive into the water to prey on these fish.

 

Beach: 1.5% and Dune: 0.8%

The white sands of Wingaersheek Beach dominate the western side of the northern mouth of the Annisquam. The dunes, which are stabilized by American beachgrass, provide habitat for Piping Plovers. Herring Gulls, Ring-billed Gulls. Common and Red-throated Loons are spotted in the waters offshore. Sand from the Great Marsh and Essex Bay shifts downstream through Ipswich Bay toward the Annisquam, altering the beach profile throughout the year. Dredged material has been piled behind the parking lot at Wingaersheek Beach in berms that have changed tidal flow over time.

 

Rocky Intertidal: 0.3%

Rocky intertidal habitat is globally scarce, and includes several zones at Lobster Cove, Goose Cove, and around the perimeter of the islands in the Annisquam. Intertidal habitat has specific zones based on salt water inundation: the splash zone with limited vegetation, the high tide zone with barnacles and periwinkles, the black-green algae zone with rockweed and bladderwrack, and the low-tide zone with kelp and benthic invertebrates. The ecosystem supports blue mussels, fish including fourspine stickleback, cunner, and birds including Herring Gulls, as well as Sandpipers that feed in the rocky intertidal habitat, and roost in the zone at high tide.⁶

Increasing sea surface temperatures and declining water quality due to pollution and chemical contamination has resulted in declining mussels and periwinkles across the world, including the Annisquam ecosystem. The decline of these species threatens the birds that feed on them during low tide. Additionally, these species are threatened by increasing carbon dioxide concentrations in global oceans, which slows the rate of shell calcification, posing a threat to shellfish.⁷

Species

These species spend all or part of their life cycles along the Annisquam. This is not an exhaustive list. Rather, these species are a lens to understand the interspecies relationships, habitat degradation, and challenges for stakeholders to restore the ecosystem.

Birds
Spotted Sandpiper (Actitis macularia)
Red-winged Blackbird (Agelaius phoeniceus)
Saltmarsh Sparrow (Ammospiza caudata)
Black Duck (Anas rubripes)
Great Egret (Ardea alba)
Green Heron (Butorides virescens)
Bonaparte's Gull (Chroicocephalus philadelphia)
Common Crow (Corvus brachyrhynchos)
Catbird (Dumetella carolinensis)
Semipalmated Plover (Ereunetes pusillus)
Barn Swallow (Hirundo erythrogaster)
Herring Gull (Larus argentatus)
Belted Kingfisher (Megaceryle alcyon)
Black-crowned Night Heron (Nycticorax nycticorax)
Osprey (Pandion haliaetus)
Least Sandpiper (Pisobia minutilla)
Tree Swallow (Tachycineta bicolor)
Kingbird (Tyrannus tyrannus)
Common Tern (Sterna hirundo)
European Starling (Sturnus vulgaris)

Jellyfish
Moon jellyfish (Aurelia aurita)
Lion's mane jellyfish (Cyanea capillata)

Crustaceans
Rock barnacle (Balanus balanoides)\ Eastern green crab (Carcinus maenas)
Sand shrimp (Crangon septemspinosa)
Atlantic slipper shell (Crepidula fornicata)
Atlantic horseshoe crab (Limulus polyphemus)
Common periwinkle (Littorina littorea)
Long-wristed hermit crab (Pagurus longicarpus)
Hermit crab (Pagarus pollicaris)
Sand-collar snail (Polinices heros)
Infauna crustaceans (Tanaidacea sp.)

Mollusks
Eastern oyster (Crassostrea virginica)
Atlantic jackknife clam (Ensis leei)\ Mud snail (Ilyanassa obsolete)
Baltic macoma (Macoma balthica)
Coffee-bean snail (Melampus bidentatus)
Soft-shell clam (Mya edularia)
Blue mussel (Mytilus edulis)

Insects
Mosquito (Aedes vexans)
Greenhead fly (Tabanus nigrovittatus)
Saltmarsh mosquito (Aedes solicitans)

Mammals
American beaver (Castor canadensis)
Humans (Homo sapiens)
Common muskrat (Ondatra zibethicus)
White-footed deermouse (Peromyscus leucopus)
Eastern gray squirrel (Sciurus carolinensis)
Eastern chipmunk (Tamias striatus)
Red squirrel (Tamiasciurus hudsonicus)

Worms and other Invertebrates
Sponge (Haliclona oculata)
Annelid (Lumbrinereis tennuis)\ Sea squirt (Molgula sp.)
Clam worm (Nereis pelagica)
Brittle star (Ophiopholis aculeata)

Fish
Blueback herring (Alosa aestivalus)
Alewife (Alosa pseudoharengus)
American eel (Anguilla rostrata)
Atlantic herring (Clupea harengus)
Skate (Dipturus batis)
Longfin inshore squid (Doryteuthis pealeii)
Mummichog (Fundulus heteroclitus)
American goosefish (Lophius americanus)
Atlantic silverside (Menidia menidia)
Silver hake (Merluccius bilinearis)
Striped bass (Morone saxatilis)
Short-horn sculpin (Myoxocephalus scorpius)
Rainbow smelt (Osmerus mordax)
Atlantic pollack (Pollachius virens)
Winter flounder (Pseudopleuronectes americanus)
Butterfish (Peprilus triacanthus)
Long-horn sculpin (Pseudopleuronectes americanus)
Atlantic mackerel (Scomber scombrus)
Greater pipefish (Syngnathus acus)
Cunner (Tautoglabrus adpsersus)
Squirrel hake (Urophycis chuss)

Vascular Plants
Saltmarsh false foxglove (Agalinis maritima)\ Rock seaweed (Ascophyllum nodosum)
Common orach (Atriplex patula)
Seashore saltgrass (Distichlis spicata)
Sea couch grass (Elymus pumgens)
Rockweed (Fucus edentates)
Bladderwrack (Fucus vesiculosus)
High tide bush (Iva frutescens)
Saltmarsh rush (Juncus gerardii)
Oarweed (Laminaria digitate)
Sugar kelp (Laminaria saccharina)
Carolina sea lavender (Limonium nashii)
Sea milkwort (Lysimachia maritima)
Sea anemone (Metridium sp.)
Bayberry (Myrica pennsylvanica)

Phragmites (Phragmites australis) *native but dominant
Pitch pine (Pinus rigida) *logged by 1757
Sea plantain (Plantago maritima)
Beach plum (Prunus maritima)
Seashore alkali grass (Puccinellia maritima)
Staghorn sumac (Rhus typhina)
Saltspray rose (Rosa rugosa) *non-native but naturalized
Glasswort (Salicornia europaea)
Goldenrod (Solidago sempervirens)
Smooth cordgrass (Spartina alterniflora)
Salt marsh hay (Spartina patens)
Sea blite (Suaeda linearis)
Seaside arrowgrass (Triglochin maritimum)
Stiff-leaf quackgrass (Thinopyrum pungens)

Changes

“In the cool bowels of the mill the boys of Riverdale knew where to look in one eddy for the fat smelt, in another hiding place for the wily eels, and in a third for the alewives. Way up the creek and in the brook where they swam to spawn, alewives made a fishery worth pursuing back then... Damn few alewives make it now; the floodgates have been locked shut, the millpond is full of fresh water and the environment was torn apart and drastically rearranged for the middle-grade O'Maley School.” —Joseph Garland, 2004, Historian⁸

The Annisquam is a drowned stream valley that has been flooded over thousands of years as the sea has risen from the melting of Pleistocene glaciers.⁹ Tree stumps buried in peat deposits beneath the low tide mark of the River help tell the story of the ecosystem. The Annisquam was once a freshwater river that flowed north to Ipswich Bay. As sea levels rose, the stream was drowned and became brackish. A natural waterway formed, flowing with the tides from Gloucester Harbor to Ipswich Bay. Over time, sediment from tidal currents built a barrier beach across the southern mouth at Gloucester Harbor, until the 1600s, when colonists dug a canal, turning East Gloucester and Rockport into an island.¹⁰ This was not the first time humans had a hand in changing the Annisquam ecosystem. The Pawtucket people used the Annisquam to fish, hunt, and camp during summers. Yet, over the past century, the rate of change along the Annisquam has increased due to Anthropogenic climate change. These changes are documented in various reports and studies from the early 1900s to the present. These studies are briefly summarized below, with a focus on the West Annisquam, including the estuary’s many islands, connecting causeways, mudflats and marshes that provide habitat for flora and fauna, and scenic landscape character for Cape Ann residents and visitors alike.

Observed Changes along the Annisquam

The Annisquam River is technically an estuary in the North Coastal watershed. The Annisquam watershed includes three main tributaries: the Annisquam River, Little River, and Mill River. Many of Gloucester’s ponds and rivers flow into the Annisquam through these tributaries, as well as creeks that are fed by wetlands, small ponds, and former quarries. Goose Cove Reservoir, Fernwood Lake, Upper Banjo Pond, Strangman’s Pond, and Goose Cove flow into the Annisquam River. Lily Pond, Wallace Pond, Dykes Meadow Pond, and Fernwood Lake drain to the Little River. Babson Reservoir and the Mill River Culvert drain into the Mill River. These tributaries are all dammed in some capacity.¹¹

Freshwater flows into the Annisquam through creeks and streams, but marine conditions dominate to the high-tide limits. The River and its tributaries are therefore tidal influenced, with conditions that are characteristic of saltwater environments. Ocean water enters both sides of the Annisquam from Gloucester Harbor and Ipswich Bay. These currents flow into the Little River during incoming tides, and flow divergently out to both sides during outgoing tides. The velocity of the current depends on the height of the tide, the direction and velocity of the wind, and the width of the channel. The mean rise and fall of the tides is eight and a half feet throughout the year.¹²

Ocean Water enters the Annisquam from the north at Wingaersheek Beach

Indigenous History

The indigenous Pawtucket people centered their lives along the Annisquam, as detailed by independent historian Mary Ellen Lepionka. Lepionka describes the origin of the term Annisquam, beginning with “Wamesit", which meant ‘Here is space for all,’ “referring to all of the people who otherwise lived on the coastal saltmarshes. Wam was the root for ‘submerged land’ or ‘land overflowed with water.’ Agawam, referring both to a Pawtucket village on Castle Neck River in Ipswich and the larger territory of which it was a part, means ‘Other side of the marsh,’ and Wenesquawam—Wonasquam on old maps and the name from which Annisquam is derived—means ‘End of the marsh.’"⁹ Lepionka further writes that Annisquam “most likely came not from Wonasquam but from Wanaskwiwam, first transcribed as Wenesquawam” from a document describing “the larger tidal rivers from the Kennebec to the Annisquam, along with the names of their principal village or sagamore at the time.” Lepionka notes that Algonquian place names were based on environmental features, and therefore many places have the same name.

Wonasquam, the Pawtucket’s main settlement, was centered around Heron Pond. Smaller settlements were founded on the Little River, Jones River, Mill River, and Wingaersheek Beach. The Pawtucket transformed the landscape with agricultural planting, controlled burns in upland areas, camps on the islands in the Annisquam, and shell middens. These middens were mined for lime and fill. The Andrew A. Piatt bridge was constructed on footings made from the Wheeler’s Point shell midden fill. Colonial settlements, including residential neighborhoods, built on these middens obscure evidence of Indigenous histories, which must be foregrounded in discussions of stewardship and care.¹³

Geology

The Annisquam’s variable coastline has been shaped by geologic weathering in addition to indigenous and colonial development. Sand and silt deposits have formed bars, beaches, flats, and marshlands. Rocky shores have been produced by glacial deposits and weathering. The bedrock geology underlying the West Annisquam south of Wingaersheek Beach is squam granite, while the rest of the region is underlaid by Cape Ann granite.¹⁴
The substrate conditions along the Annisquam vary. The Little River bottom materials and southern channel
from Gloucester Harbor to the Little River are find mud deposits with sand. Shelly, rocky bottom north of the railroad bridge continues to the northern inlet from Ipswich Bay to the Little River. Marsh banks, low marsh, and high marsh are found interspersed throughout the Annisquam.¹⁵ The River includes shellfish beds, wetlands, and coves for recreational boating, with marinas, moorings, and many access points for kayaks and other watercraft.¹⁶

Jones River Marsh

Navigable Waterway

The colonial history of the Annisquam is tightly connected to navigation and transport along the four and a
half-mile waterway. In 1643, Pastor Blynman dug the Blynman Canal at the south end of the channel, connecting the tidal river to Gloucester Harbor. A swinging bridge was erected over it. “The Cut” enabled boats to pass through the Annisquam and avoid the passage around East Gloucester and Rockport. "The Cut" filled with sand in 1704 and again in 1723.¹⁷ The bridge over Blynman’s Canal, called “The Cut” Bridge, was constructed in 1907, when the Commonwealth of Massachusetts dredged the river. Dredging operations have transformed the bottom of the Annisquam.

Annisquam is dredged to maintain navigability

The River was originally six feet deep from the Ipswich Bay to Little River at mean low-water, and two feet above mean low-water level by Blynman Canal. Dredging to eight feet depth and straightening the channel has significantly altered the flow and substrate along the Annisquam, affecting the tidal communities that live in sediments along the River.¹⁸ The US Army Corps of Engineers completed the Annisquam River Navigation Project in July 1965. The project included an eight-foot-deep channel from Gloucester Harbor to Ipswich Bay. The channel was dredged in three separate widths: from Gloucester Harbor to the Boston and Maine railroad bridge the channel is sixty feet wide; from the railroad bridge to the river mouth the channel is one-hundred feet wide; from the river mouth to Ipswich Bay the channel is two-hundred feet wide. The Army Corps also dredged a seventeen-acre anchorage in Lobster Cove to eight-feet-deep.¹⁹ These dredge operations are ongoing. Dredge from the Annisquam River has been placed behind Wingaersheek Beach and at the Gloucester Historic Disposal Site. Dredge material may be placed in the Ipswich Bay Nearshore Disposal Site in the future.²⁰²¹

Dredge Spoils Behind Wingaersheek Beach

Today, there are three fixed crossings across the Annisquam River: Massachusetts Route 128, the MBTA Rockport/Newburyport Line of the Commuter Rail, and Massachusetts Route 127 (Western Avenue) at the Blynman Canal. Route 128 was constructed in 1953. The Squam River Marsh was destroyed to make way for Grant Circle, part of Route 128.

Highway built over Marsh

Pollution

Road construction and upland development directly impacts the Annisquam ecosystem. Polluted runoff from roadways, sedimentation, and stormwater flow directly into the Annisquam, impacting critical habitat for fauna, including shellfish. There are thirty-nine clam beds in the Annisquam, separated into Upper and Lower Annisquam River areas.¹¹ Three shellfish flat areas are closed seasonally due to water quality: the Jones River, Cross Creek, and Little River. These beds are also closed after rainfall events with one inch or more of rainwater due to stormwater running into the River carrying pollutants and increased nutrient loads from upland areas. These beds are primarily for soft-shell clams (Mya arenaria), the most important commercial and recreational species. European green crab, the dominant invasive species in the Annisquam, which feeds on juvenile soft-shell clam seeds and is highly destructive to marsh grasses, are also present in the marsh.

Shellfishing is prohibited in Gloucester Harbor north to the Gloucester Drawbridge, along Green Landing and Marsh, as well as Lobster Cove, and areas along Route 128.²² Pollution abatement will increase the yield of shellfish or crustaceans. In 1980, thirty percent of productive soft-shell clam beds were closed due to pollution from coliform bacteria. This was due to sewage dumped in Gloucester Harbor that travels up the Annisquam due to currents.²³ The estimated yield of soft-shell clams was approximately 6,560 bushels. Hruby notes the costs of delaying action on the wastewater treatment plant, estimating that the income from fully open clam beds would have paid for the City of Gloucester’s share of the costs of a sewage treatment plant.²⁴ The lost income from shellfish beds due to pollution continues to be substantial in the present day.

Shellfishing Beds throughout the Annisquam

The Gloucester Shellfish Department is also building an Eastern oyster population in the Mill River by seeding Eastern oysters (Crassotrea virginica) into an existing European oyster bed. Government efforts are bolstered by non-profit organizations including Mass Oyster., which partnered with Maritime Gloucester in 2017 to build an upweller on a pier in downtown Gloucester. The project collects water quality data from water entering and exiting the upweller to measure oysters’ impact on local water pollution, and educate visitors and student groups. The upweller has nurtured two hundred thousand oysters that have been released across the North Shore on limited sites that are coordinated with the Massachusetts Division of Marine Fisheries and each Town’s shellfish wardens.²⁵ Eastern oysters (Crassotrea virginica) in reefs can protect against storm surge, mitigate ocean acidification as natural bicarbonates, and prevent coastal erosion.²⁶ Reefs can also provide habitat for two hundred other species. Oysters prefer rock and shell substrate, with lower salinity, steadily flowing water. Oysters are often the first species to establish in disturbed environments, making urbanized coastal estuaries like the Annisquam River well-suited for their propagation.²⁷

In addition to shellfish, river herring and winter flounder use the Annisquam River to spawn. Rainbow smelt, American eel, white perch, and Atlantic cod also use the Annisquam for habitat, though they do not spawn in the waters.²⁸ Alewives and eels also rely on the Annisquam. The Little River alewife count occurs in April to May, as alewives pass through the herring ladder from the Little River to Lily Pond. Eels live in the Pond, while alewives spawn and then return to the ocean. The fish-way in the Little River was redesigned in 2016 as part of a restoration project to allow for passage of herring and eels.²⁹

Marsh Ditching

Ditching has been practiced historically throughout Cape Ann as a part of colonial haying and cropping operations and as mosquito control through New Deal work programs. ³⁰ This process has changed water flow and sedimentation patterns and quickened erosion, increasing the landscape’s susceptibility to sea-level rise. There are over one 128 miles of ditches throughout Cape Ann's saltmarshes, or approximately the distance from Gloucester to Hartford, Connecticut.³¹

Marsh Ditches throughout the Annisquam

There have been several efforts to remediate ditches throughout the Great Marsh system. Utilizing grants from the North American Wetland Conservation Act (NAWCA), restoration efforts have been funded for 1,274 acres of marsh in Newbury, Essex, and Ipswich. ³² Land included in the project is owned by The Truststees of Reservations, The Essex Greenbelt, and the Massachusetts Division of Fisheries and Wildlife. The project has served as a valuable pilot which has created a proven model for restoration.

Species Change

The Annisquam provides habitat for a variety of flora and fauna beyond commercially and recreationally valuable species from the depths of the benthic environment in the northern Ipswich Bay to the shallow waters along the Jones River. Certain species have been documented and studied over time, including eelgrass (Zostera marina L.), a marine grass that sequesters significant amounts of carbon, and provides important habitat for marine life. Eelgrass was almost completely eradicated along the Atlantic coast in 1931 to 1932 due to a wasting epidemic, but was documented in Goose Cove between 1945 and 1947, and in recent years the Massachusetts Department of Environmental Protection has documented eel grass growing along both ends of the Annisquam River.³³ Today, there is a 10.67 acre eelgrass bed at the northern mouth of the Annisquam River, and two beds on either side of the Blynman Canal, one 7.29 acres to the east of the Bridge and 9.39 acres to the west of the bridge.³⁴ Other single species efforts include the live Osprey Cam operated by Essex County Greenbelt in the Greenbelt saltmarsh to document the species.

Ospery Nest near Lobsta Land

Detailed studies of individual species like osprey and eelgrass do not provide a comprehensive record of the ecology along the Annisquam.

A comprehensive 1947 study by Ralph W. Dexter across twenty-four sites from Gloucester Harbor to Lobster Cove found several different marine and terrestrial communities organized by dominant and characteristic species. The pelagic community is similar to the shallow water of Ipswich Bay, with fish species including mackerel, herring, pipefish, pollack, alewife, butterfish, bluefish, silver hake, smelt, common squid, and jellyfish. The Common Tern and Belted Kingfisher also belong to this community, as they dive into the water to prey on fish. Plankton including diatoms, protozoans, microcrustraceans, and crustacean larvae are present throughout the marine waters.³⁵ The plankton feed on organic matter and debris in the water column, which is also found buried in the sand and mud along the bottom of the channels. The subtidal bottom community, including bivalves and starfish, were affected by dredging operations through the channel.

Seaweed including Fucus species, (Laminaria digitata), and (*Laminaria saccharina *) create microhabitats for small animals.³⁶ Tidal communities in sediments along the Annisquam include shellfish and crustaceans. Soft-shell clams grow a few inches above the spring low-water line to the top of sand bars and marshland on beaches and mudflats.³⁷ Shorebirds, including herons, gulls, and crows, use the shoreline as a hunting ground. Along the hard surfaces of the Annisquam, including glacial boulders and rocky intertidal beaches, additional tidal communities are characterized by rock barnacles, blue mussels, periwinkles, and seaweed.³⁸

The saltmarsh communities of the Annisquam fall into two primary vegetation zones. Low marsh, or smooth cordgrass (Spartina alterniflora) occupies the marsh banks between lower shores and high marshlands, with five foot banks that range to the mean high water line. These banks form an almost continuous channel along the Annisquam. The endangered Saltmarsh Sparrow and American Black Duck were both documented in the study. High marsh areas are dominated by saltmarsh hay (Spartina patens).³⁹ An updated comprehensive study similar to Dexter's work would provide a comprehensive baseline to understand how the Annisquam has changed over the past fifty years.

Relationship between Marsh Habitats

More recently, Salem Sound Coastwatch. conducted an additional comprehensive baseline survey centering on Mill Pond in 2008 after the tidal gate at the Mill River was opened in 2004. The upper Mill River was ponded in 1677. A tide gate was installed in 1989, and opened in April 2004 to restore partial tidal flow to Mill Pond. The tide gate is operated by the City of Gloucester, which monitors the gate and adjusts its position during major rainfall events.⁴⁰ The study found that soft-shell clam numbers were not increasing, but Macoma balthica was the dominant species in the restored upper Mill River. Benthic species returned to the upper Mill River, and soft-shell clams recolonized newly exposed mudflats. Salem Sound Coastwatch recommended additional tidal gates to increase tidal exchange and further benefit these species.⁴¹

A 2006 study focusing on rainbow smelt similarly recommended tide gates along the Mill River, and restoration efforts along the Little River, which was former a smelt run.⁴² The study found that smelt habitat is limited along the Little River due to the elevation rise from the upstream fishway and high salinity downstream of Route 133. Alewives also enter the Little River, and juvenile American eels aggregate on the upstream side of the Route 133 culvert. While the study found ten creeks with potential smelt spawning habitat, the sedimentation from roadways near these areas, development, and drainage alterations limit the potential for smelt populations along the Annisquam. Further, the freshwater creeks on Cape Ann were determined to have low buffering capacities against acidic waters due to the underlying bedrock geology of the region.⁴³ The study recommended increasing flushing at the Mill Pond tidegate to benefit marine life in Mill Pond; improving operations and maintenance at the Little River Water Treatment Plant; and making road and drainage improvements with fish habitat in mind.⁴⁴

Restoration Projects

There are additional projects to consider. The 2003 Mass Audubon report authored by Tim Purinton identifies sites for restoration in Gloucester focuses on anadromous species that enter fresh water from the ocean to spawn. Species include rainbow smelt (Osmerus mordax), alewife (Alosa pseudoharengus), and blue back herring (Alosa aestivalis). A single catadromous species, the American eel (Anguilla rostrata) which enters salt water from fresh water to spawn, was also considered.⁴⁵ The report considered a limited number of restoration activities: buffer enhancement, bank improvement, channel realignment, culvert upgrade, stream daylighting, dam removal, fill removal, fish/eel ladder, invasive plant species management, open marsh water management, roughened ramp, fish and shellfish stocking, storm water best management practices, and trash removal.⁴⁶ The report identified eighteen projects in the Annisquam River watershed, and an additional five projects in the Jones River/Annisquam watershed.⁴⁷

Infrastructure in the Marsh prevent species movement

It is critical that restoration projects along the Annisquam use best management practices, and are designed based around the life cycles and habitat requirements of the species that rely on the ecosystem. Marine fisheries resources, including specific life stages and habitats, are vulnerable to coastal alteration projects. The Massachusetts Department of Marine Fisheries has outlined times of year when coastal alterations should be avoided to protect species with spatially limited habitats, low populations, and vulnerable life stages. Adverse impacts on species include the suspension of fine grain sediments, lowered dissolved oxygen levels, barriers to migration, direct removal of shelter, forage or spawning habitat, and direct mortality. Projects can be designed to minimize the size and footprint; use a particular construction technique; create real-time monitoring of the project site; use project sequencing at different times in different areas of the water body; and use time of year restrictions on in-water work.⁴⁸ Recent research also suggests that the Essential Fish Habitat for the Gulf of Maine winter flounder should include near-shore coastal waters during the spawning season from late April to early May.⁴⁹

Marsh Restoration

Restoration efforts along the Annisquam have already been undertaken. The Little River restoration project was completed in 2016. The project day-lighted portions of a buried waterway, replacing an aging concrete channel with a natural stream bed, and restored coastal wetlands.⁵⁰ In 2022, Gloucester re-entered the North Shore Greenhead Fly Program, and installed twenty box traps in the salt marsh around Wingaersheek Beach at a cost of $4,120. The flies are present along the Annisquam from June to September, and have impacted real estate values while limiting beach, golf course, and other recreational activities.⁵¹

Despite these projects and increasing ecological awareness, habitat continues to be degraded along the Annisquam due to general coastal development pressures including contaminated water from sewer and stormwater systems, increases in runoff from impervious surfaces, and the disturbance of passing recreational boats.⁵² Additional disturbances along the Annisquam River include docks, floats, piers, jetties, and shoreline armoring. These disturbances will be exacerbated by sea level rise due to climate change.

Flooding

Several areas along the Annisquam River flood annually. Newell Stadium was constructed on a filled saltmarsh below sea level and has been submerged during nor’easters.⁵³ Across the Annisquam, the West Gloucester Water Treatment Facility, which is also built below sea level. A berm project to armor the plant is underway.⁵⁴ The largest projected changes along the Annisquam are in the northwest area of the ecosystem. The upper Annisquam is projected to lose forty-five acres of upland areas due to increasing sea level rise by 2030. Roads and property will potentially begin to convert from uplands to wetlands, if they are allowed to do so. By 2030, there will also be significant low marsh to high marsh transitions along the Annisquam, particularly in the northwest. Some tidal swamp and fresh marsh systems along Route 133 are also anticipated to change to saltmarsh. Along the edges of the islands in the Annisquam, existing low marsh will transition to non-vegetated tidal flats.

By 2070, 729 acres, or almost all of the saltmarsh systems along the Annisquam, are projected to transition from high marsh to low marsh, which indicates a significant breakdown of biodiversity in the system, and eliminates critical habitat for obligate species that rely on high marsh for food and habitat, including the endangered Saltmarsh Sparrow. There is an additional loss of 215 acres of upland areas to wetlands as sea level rises as well.

Flooding will continue to drown Low Marsh Habitats

An additional 136 acres of tidal flats along the islands, and 113 acres of tidal creeks will emerge. These tidal creeks along the Annisquam will widen due to increased water levels and tidal exchange. The Annisquam River is projected to be close to transitioning to an open water harbor by 2070, with limited ability for the marsh to migrate due to the steep topography behind the marsh, leading to the continued loss of marsh habitat. As the marsh is degraded, it will lose its ability to buffer waves due to storm surge, making the roads and properties behind the marsh increasingly vulnerable to waves and storm surge.⁵⁵ In addition to flood hazards, there is a fire hazard in the West Gloucester Watershed Lands.⁵⁶

Conclusion

The Annisquam River Ecosystem is a dynamic interface between saltwater, freshwater, marshland, and developed areas. Human influence has altered the path of the River, its tributaries, and the species living there for thousands of years. The Annisquam will continue to change and evolve. Innovative actions and novel techniques that anticipate the way the Annisquam is already changing, such as stocking species and investing in nature-based infrastructure, can help ensure that the Annisquam continues to provide food, habitat, and enjoyment for humans, birds, and shellfish alike into the future.

See potential initiatives organized into scenario plans in the next section, Marsh Scenario Plans.