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The Bay of Fundy and Its Wetlands (Canada)

  • Graham R. DabornEmail author
  • Anna M. ReddenEmail author
Reference work entry

Abstract

The Bay of Fundy is a highly productive and biologically diverse ecosystem. Noted for the highest tides in the world, it is biologically connected to the Americas, Europe and the Arctic. Its highly productive salt marshes and tidal flats have been extensively modified by human activity, but still provide critical habitat and organic matter supporting numerous migratory species of fish, birds and marine mammals.

Keywords

Hypertidal ecosystem Biodiversity Salt marshes Intertidal mudflats Conservation issues 

Introduction

By almost any measure, the Bay of Fundy is an extraordinary estuarine system. With the world’s highest tidal range, a great diversity of habitats and organisms, and biological connections that link the Bay to the whole of the Atlantic, the Americas, and Europe, it is a complex and highly productive ecosystem that presents substantial challenges for its management and conservation. An important part of its international significance is associated with the salt marshes and tidal flats that occur primarily in the innermost portions of the bay.

The Bay of Fundy originated from a tectonic rift that formed during the break up of Pangea during the early Triassic (250–190 mya; cf. AGS 2001). An original Fundy Basin subsequently began to fill with sediments, forming the red sandstones that are now exposed in the innermost (eastern) portions of the bay. During the Early Jurassic (190–142 mya), basaltic lava flows resulting from continental breakup emerged through the crust and now form most of the floor of the bay as well as a long, resistant ridge that constitutes the south-eastern (Nova Scotia) shore. As a result of these processes, the bay has a very different character from one end to the other: the western regions are bordered by basalt and other resistant materials, forming rocky shorelines and intertidal zones, whereas the more eastern portion of the bay is bordered by more sand- and mud-stones that provide the fine sediments forming extensive intertidal flats. Because the morphology of the Bay varies substantially from one end to the other, it is convenient to recognize three major regions: the Outer Bay, the Inner Bay, and the Upper Bay (see Fig. 1). Water in the Outer Bay is exchanged with the Gulf of Maine and Atlantic Ocean on each tide and is clear, with a photic zone that extends down to 20+ m, whereas the Upper Bay is characterized by highly turbid waters and a photic zone that ranges from a few meters to a few millimeters (Brylinsky and Daborn 1987).
Fig. 1

Regions and tidal ranges of the Bay of Fundy (Adapted from Hagerman et al. 2006 and drawn by B. Sanderson)

Physical Characteristics

The Bay of Fundy is an integral part of a complex coastal oceanographic system (referred to as the Fundy – Gulf of Maine – Georges Bank or FMG system; see Fig. 2) that also includes the Gulf of Maine, Georges and Browns Banks, and the various channels between them. The total area of the FMG system is nearly 180,000 km2, of which the Bay of Fundy constitutes 16,000 km2. Water entering the system on the flood tide is derived in part from northern latitudes through the cold Nova Scotia Current but may also include warmer southern waters brought north by the Gulf Stream. Periodically, large scale eddies in the Gulf Stream release “warm core rings” (see http://marine.coastal.edu/gulfstream/p5.htm) that drift north over the colder water, introducing species of tropical and subtropical origin into the FMG system. Water entering the Outer Bay during the flood tide tends to advance along the southern (Nova Scotia) shore, producing an anticlockwise circulation in the Outer and Inner Bays, which is amplified by less dense fresh water entering from the principal river (Saint John River) along the northern shore.
Fig. 2

Bay of Fundy-Gulf of Maine-Georges Bank system (Source: Adapted and redrawn from Gulf of Maine Area Census of Marine Life http://www.gulfofmaine-census.org/about-the-gulf/oceanography/circulation/)

In many ways, the FMG system responds as a unit to the semi-diurnal tidal forcing of the Atlantic Ocean. However, specific responses vary among the different regions of the FMG system as a result of past geological factors that shaped local morphology and of more recent natural and anthropogenic influences. Many dynamic oceanographic processes, such as sea level rise, channel deepening, shoreline erosion, and post-glacial land settling, result in continuing and progressive changes to the physical characteristics of the bay. Added to these natural processes are the anthropogenic effects of dam and harbor construction, dredging, marshland conversion, shoreline modifications, and changes to freshwater inputs.

As a whole, the Bay of Fundy may be considered an estuary (i.e., the sea water is measurably diluted with fresh water – see article on Estuaries this volume), but the freshwater input from rivers is very small relative to the inflow of oceanic water. Salinity ranges from 30 to 32 ‰ in the Outer and Inner Bays and 20–28 ‰ in the Upper Bay; lower salinity conditions are restricted to the mouths of inflowing rivers, but because of the great tidal range these brackish waters may extend upriver for many kilometers.

The bay has a semi-diurnal tidal system, with two full tidal cycles occurring each 24.84 h driven by the Atlantic tide. The bay becomes notably more shallow and somewhat narrower with distance from the Gulf of Maine, and because its length (270 km) and volume are closely matched to the principal constituent of the tide (i.e., the M2 tidal constituent, which reflects the semi-diurnal variation of the Moon’s gravitational effect), it is a near-resonant system. This results in amplification of the 4–6 m tides at the mouth to the world’s highest recorded tides (16+ m) in the Upper Bay. As with estuaries elsewhere, cyclical changes occur in tidal amplitude in association with lunar phases (e.g., spring-neap cycles), variations in lunar and solar distances (apogee-perigee, aphelion-perihelion), and longer tidal cycles such as the 18 year Saros and Nodal cycles (Desplanque and Mossman 2004). With the amplification of the tidal range, the effect of these cycles on water levels is magnified, especially in the Upper Bay.

Biological phenomena reflect the fact that the Bay of Fundy is fundamentally a physically driven hypertidal system. Strong tidal currents advancing over shoaling depths result in extensive vertical mixing through most of the bay, but mixing is especially pronounced at the entrance to the Outer Bay, in or near narrow channels and passages, and throughout the Upper Bay. Only in spring and summer does a central part of the Outer and Inner Bay tend to stratify (Garrett et al. 1978; Greenberg et al. 1997). Vigorous vertical mixing has important effects on biological productivity, especially through return of nutrients to surface waters where they may stimulate primary production. Upwelling zones, especially in the Outer Bay, also bring deeper-lying zooplankton to surface waters where they may become a concentrated food source for fish, birds, and baleen whales and moves surface waters down to the bottom where their contents (phytoplankton and other particles) may be accessed by benthic organisms (Daborn 1986; Emerson et al. 1986). The extent of vertical mixing varies over time with fluctuations in tidal range, producing cyclical changes in sea surface temperature and affecting rates of biological production that are detectable in fishery statistics (e.g., Cabilio et al. 1987; Campbell and Wroblewski 1986).

Current velocities on flood and ebb are >1 m s−1 over most of the Bay but may reach >6 m s−1 in narrow passages. The highest velocities scour the substrate to bedrock, leading to impoverished benthic communities. More moderate currents are associated with gravel or sand waves that occur throughout the bay or allow more productive and diverse benthic communities to occur where hard substrates are exposed (Wildish and Fader 1998).

The extreme hypertidal range (9–16m+) in the Upper Bay results in a large intertidal zone up to several kilometers in width. Because of the erodibility of nearby shorelines, the sediment contribution of rivers, and the typical flood-ebb inequality of estuaries, the intertidal habitat in the Upper Bay is dominated by sands, silts, and muds. These sediments are highly mobile, are frequently resuspended by wave and tidal action through much of the year, and may be completely reworked by ice during winter months. Ice is an important but highly variable physical force in the Upper Bay: in some winters, large sheets of pan ice may become broken and piled up into shore-grounded, sediment-laden icebergs that scour the intertidal substrate as they move. As a result, the benthic community is dominated by burrowing or epibenthic (mobile forms living at the sediment surface) animals rather than the many sessile forms that dominate rocky substrates. The regular reworking of sediments in the Upper Bay represents a physical stress that restricts the benthic fauna to pioneering species that can rapidly resettle disturbed areas (Daborn 2007). With little competition, successful species can become extremely abundant within the extensive intertidal flats, which offer a rich feeding ground for millions of fish and birds that migrate very great distances.

Biodiversity

Because of the major changes in morphology, water column stability, and substrate characteristics over the 270 km length of the Bay of Fundy, there is a great variety of habitats. Day and Roff (2000) classified regions of the Bay of Fundy according to seven physical attributes: surface and bottom water temperatures, depth, stratification, exposure, slope, and sediment type. This classification into “seascapes” (defined as: “broad, oceanographic and biophysical areas characterized by particular water-mass characteristics and sea-ice conditions” (Bredin et al. 2004)) helps to tie together the physical environmental characteristics and the biological characteristics of the bay. It distinguishes between several regional differences: shallow near-shore habitats in the Outer and Inner Bay are significantly different from deeper regions; there are differences between the northern (or New Brunswick) portions of the Outer Bay and the southern (Nova Scotia) side; and the turbid, well-mixed region of the Inner Bay is distinct from both the clearer Outer Bay and the even more turbid Upper Bay, where substrates are dominated by finer sediments. The classification also clearly shows that habitat differences occur over short distances around the islands and banks near the mouth of the bay.

It is partly this broad diversity of habitat that gives rise to the bay’s considerable biodiversity: two thirds (>2,300) of all the species known from the FMG system (c. 3,400 species) occur in the Bay of Fundy which is only 9% of the total FMG area (AECOM 2010). Some 15 different seascapes occur in the bay, ranging from deep passages with rocky substrate, to mobile sand and gravel waves, and to extensive intertidal habitats of sand or mud. Each supports a different combination of flora and fauna. The Outer Bay is deep in the center (100–200+ m), bordered by resistant rock, and floored by either bedrock or mobile sands or gravels. The food web in this outer region strongly resembles that of other coastal waters and bays: the water tends to be clear and supports a diverse plankton community dominated by diatoms (>160 spp.), dinoflagellates (at least 65 spp.), copepods, coccolithophorids, and invertebrate and fish larvae. In this Outer Bay region, phytoplankton primary production is dominant (See Fig. 3). Much of the primary production is processed in the pelagic zone (Emerson et al. 1986), supporting pelagic fish, marine birds, and baleen whales, rather than benthic communities and groundfish.
Fig. 3

Distribution of primary production in the Bay of Fundy (Drawn from data in Prouse et al. 1984)

In the rocky intertidal and near-shore subtidal zones of the Outer Bay, seaweeds are abundant, providing a complex habitat for numerous species of mobile and sessile invertebrates. The seaweed community consists mainly of rockweed (e.g., Ascophyllum nodosum) and fucoids (Fucus vesiculosus, F. serratus, F. edentatus, and F. spiralis) within the intertidal zone and dulse Palmaria palmata, Irish moss Chondrus crispus, and kelps (Laminaria digitata, L. longicruris, Alaria esculenta, and Agarum cribrosum) in the lower littoral and sublittoral zones. Rockweed and Irish moss are harvested on a commercial scale. Numerous invertebrate species live within and attached to the fronds, and seaweed associations constitute important nursery grounds and refuge for many fish species. Although few animals, with the notable exceptions of sea urchins and some isopods, graze directly on seaweeds, the export of both dissolved and particulate organic matter from seaweed communities is thought to be an important source of nutrients to offshore waters: as much as 80% of total annual production is exported from the intertidal zone during the summer months. In addition, fragmentation of seaweeds by waves, especially during storm events, results in “rafts” of seaweeds being exported to the pelagic zone where they constitute an important floating habitat and feeding area for seabirds, various marine invertebrates, and juvenile fish (cf. Daborn and Gregory 1983). Although providing a small fraction (1–2%) of the total primary production in the Outer Bay, seaweeds provide both important organic input and critically important habitat.

On exposed subtidal bedrock with moderate currents (1–3 m s−1), dense benthic populations of sessile coelenterates, sponges, mussels, tunicates, and their associated mobile fauna (including shrimps, lobsters, and crabs) occur. In higher velocity areas (>4 m s−1), the bedrock is scoured and only a few species of sponges and coelenterates appear to be able to withstand the flow. The high productivity of the Outer Bay is clearly linked to extensive upwelling zones where tidal currents meet rapidly shoaling waters, which not only sustain important resident fish and fisheries but also attract large numbers of migrant fish, birds, and mammals.

In the offshore waters of the Outer and Inner Bay regions, more than half of the substrate is of highly mobile sands or gravels that form tidally controlled waves or dunes up to several meters in height and many meters in length, oriented across the direction of tidal currents. Here the benthic community is primarily composed of mobile animals such as scallops Placopecten magellanicus and lobsters Homarus americanus, with a smaller number of burrowing polychaetes, amphipods, echinoderms, and molluscs. Fisheries for lobster and scallop are the most valuable in the Bay. Over much of the Outer and Inner Bay, there are also elongated sandy ridges up to several kilometers in length, lying parallel to tidal current direction, that are capped by dense growths of horse mussels Modiolus modiolus which may stabilize the ridges and provide additional microhabitat for other benthic organisms (Wildish et al. 1999).

The Upper Bay, on the other hand, has very little exposed rocky substrate except for sandstone ledges that are swept by sediment-laden water on each tide, and deep channels, such as the entrance to Minas Basin where extreme currents (>6 m s−1, Fig. 4) completely scour the bottom, leaving either bedrock or a boulder-scale post-glacial lag. In the latter environment, benthic forms are restricted to flow-resistant sponges and occasional echinoderms, polychaetes, and molluscs that occupy refuges around large boulders (AECOM and ATEI 2013). Over the majority of the Upper Bay, sandstone ledges are overlain by various combinations of sand, silt, and mud that are highly susceptible to disturbance by waves, tidal currents, and winter ice.
Fig. 4

Minas Passage featuring strong tidal currents at Cape Split (Photo credit: C. Buhariwalla ©)

The Bay of Fundy provides habitat for a great variety of fish species (at least 120 spp. – GOMA 2014). These include some permanent residents, several anadromous species that spawn in Bay of Fundy tributaries and go to sea to grow, and others that migrate into the bay from many parts of the North Atlantic solely to feed. Several species, including herring Clupea harengus, cod Gadus morhua, haddock Melanogrammus aeglefinus, halibut Hippoglossus hippoglossus, shad Alosa sapidissima, and pollock Pollachius virens, are or have been the basis for extremely important fisheries, although populations of a number of these have declined over recent decades. Other species play significant roles as forage fish. The anadromous species utilize the marine and estuarine resources of the bay to varying degrees, some passing quickly through to offshore waters, while others spend longer foraging in different regions of the bay. The diversity of habitats existing in the Bay of Fundy is a critical feature that supports this diverse and productive group of animals.

The bay also supports more than 170 species of marine birds and up to 24 species of marine mammals. Most are migratory, traveling to the Bay from the Canadian Arctic, Europe, and the North and South Atlantic. A few including harbor porpoise Phocoena phocoena, harbor seal Phoca vitulina and grey seal Halichoerus grypus, Great black-backed gulls Larus marinus, and black duck Anas rubripes are year-round residents, and these are the only ones to be seen regularly in the Upper Bay. All of the other mammals including the North Atlantic right whale Eubalaena glacialis, humpback Megaptera novaeangliae, finback Balaenoptera physalis, sei B. borealis, minke B. acuterostrata, and long-finned pilot whale Globicephala melaena and more than 60 species of marine birds tend to concentrate near the major upwelling regions of the Outer Bay or follow fish (especially herring) stocks as the latter move around the Outer Bay and Gulf of Maine.

Marshes and Tidal Flats

The food web in the Upper Bay is distinctly different from that of the Outer and Inner Bay regions because high turbidity limits phytoplankton production and absence of rocky substrate provides no habitat for seaweeds and their associated fauna (see Fig. 3). As a result, a significant fraction of energy flow is heterotrophic. Primary producers include the macrophytes and blue-green algae of peripheral salt marshes and benthic diatoms occurring at the surface of intertidal flats during the summer months. Seaweeds are uncommon except for isolated patches of rockweed on exposed sandstone or boulders and some kelp in clearer waters near the mouth of the Minas Basin. In the Upper Bay, phytoplankton are light-limited because of high suspended sediments (Brylinsky and Daborn 1987); consequently, benthic diatom production occurring during low tide exposure over five summer months accounts for about 30% of the total primary production, and salt marshes now provide about 13% (Fig. 3). An unknown amount of organic matter is also derived from surrounding agricultural land through river input.

Intertidal benthic diatoms (including species of Gyrosigma, Navicula, Pleurosigma, and Nitzschia) are a high quality food source and are subject to considerable grazing pressure by deposit-feeding polychaetes and crustaceans: the latter form a major food source for fish and various waterfowl, both resident and migratory species. This intertidal community is especially important in supporting the major staging area for migratory shorebirds (which include sandpipers (Calidris pusilla, C. minutilla), plovers (Charadrius semipalmatus, Pluvialis dominica, P. squatarola), knot (Calidris canutus), and dunlin (C. alpina)) that feed mainly on mud shrimp Corophium volutator or polychaetes during the late summer before flying south for the winter. The arrival of about two million shorebirds from Arctic breeding grounds in July and August results in significant changes in benthic algal production and sediment erodibility of the mudflats of Minas Basin (Daborn et al. 1993).

Because of the large tidal range, about one fifth of the area of Minas Basin (1,900 km2) is intertidal, with sandy substrates towards the low and high water marks where wave action tends to be concentrated and a dominance of finer sediments such as silts and clays in the mid-tide zone. Coarse sand deposits are inhabited by a relatively sparse group including soft-shell clams Mya arenaria, burrowing isopods (e.g., Chiridotea coeca), and various polychaetes (Nephtys, Neanthes, Nereis spp.). Sometimes the sand is stabilized by tube-dwelling polychaetes (e.g., Clymenella torquata) which construct sand-grain tubes that resist wave scour. In calmer locations, the sediment tends to have higher clay content, and the infauna is dominated by a few species of polychaete worms (Heteromastis, Nereis, Glycera, Spiophanes spp.) and the burrowing amphipod Corophium volutator. In some places, especially near to salt marshes, large numbers of the small clam Macoma balthica occur, and in other locations numerous mud snails such as Ilyanassa obsoleta occur. There appear to be dynamic competitive interactions between Ilyanassa and Corophium that may play important roles in the support of migratory shorebirds (Hamilton et al. 2003). Benthic diatom abundance is strongly seasonal, with blooms occurring in summer months when temperatures are high and daylight exposure is long. Outside of this season, the invertebrates are heterotrophic, dependent upon microbial food associated with the breakdown of organic matter originating in nearby salt marshes or derived from inflowing rivers.

Salt marshes are found around the Bay of Fundy and cover about 153 km2 (Wrathall et al. 2013), but the vast majority that remain occur in the Upper Bay. Fundy marshes are typically two-zoned, with high marsh plants (e.g., Spartina patens, Juncus gerardi, Plantago maritima) occurring above mean high water, and intertidal marsh plants – mainly Spartina alterniflora – which dominate below mean high water (Redfield 1972). In addition to the macrophytes, Fundy marshes commonly contain blue-green algal mats in summer that at times may cover the sediment surface, and may be grazed by a number of molluscs and polychaetes. Salt marshes provide habitat for both terrestrial and marine organisms. Terrestrial species include numerous insects and spiders, and various species of waterfowl use salt marshes as breeding and over-wintering habitat. Snails and shellfish are often found within the substrate of marshes, and small fish are common to the tidal creeks and ponds associated with marshes.

Recent studies of salt marsh production in the Upper Bay of Fundy have indicated that, in spite of the northern latitude and short growing season, Fundy marshes (Fig. 5) rank among the most productive in North America – on a par with the Gulf of Mexico (cf. Kirwan et al. 2009). Estimates of mean above-ground annual production of S. alterniflora range from 500 to 900 g.m−2.yr−1 in Texas and Louisiana (28°N), 400–600 g.m−2.yr−1 in North Carolina (35°N), and 400–1,800 g.m−2.yr−1 in Minas Basin (45°N) (ibid.; Wrathall et al. 2013). Unlike many southern marshes, the high tidal energy, open coastline, and winter ice results in most of the above-ground S. alterniflora production being cast up on shore where it decays or is exported into deeper water during the fall and winter months. In this way, Spartina becomes an important part of the detrital food chain (Gordon et al. 1985; Cranford et al. 1989). The harsh winter conditions may be the reason for the absence of insect herbivores in Fundy marshes, and so the above-ground biomass of Spartina is essentially ungrazed during the growing season. Consequently, the trophic cascade model of salt marsh regulation described for New England marshes (cf. Silliman and Bertness 2002; Silliman and Bortolus 2003; Bertness et al. 2008) does not appear to apply to the Upper Bay. However, a trophic cascade effect has been detected for the intertidal mudflats during the summer months when vast numbers of shorebirds reduce intertidal grazer populations, release benthic diatoms from grazing control, leading to a mid-summer bloom, and thereby changing the erodibility of the mudflats (Daborn et al. 1993).
Fig. 5

Bay of Fundy saltmarsh. Dominated by Spartina alterniflora, with height of 2 m and above-ground production < 1,800 g.m−2 during a 4-month growing season (Photo credit: G. R. Daborn ©)

Together, the marshes and mudflats of the Upper Bay of Fundy constitute a rich, seasonally productive system that is physically stressed by tidal exposure, strong currents, and winter ice. The result is low diversity, but very high production that supports millions of fish and marine birds, many of which migrate there to feed, as well as providing organic detritus that contributes to food webs of the Inner and Outer Bay regions. The fact that more than 80% of the marshes that existed when Europeans first began to settle the region in the early seventeenth century have since been “reclaimed” for agricultural purposes, leads to interesting speculation about the nature of the Fundy ecosystem in pre-Contact times.

Conservation Status

The productivity and diversity of habitats and species in the Bay of Fundy, the extensive migratory connections with distant ecosystems, the cumulative effects of 400 years of human influence, and the prospects of climate change underlie conservation concerns about the bay (Daborn and Dadswell 1988; Wells 1999). These concerns may be grouped under three categories: protection of species and habitats at risk; recovery of features that have been modified by human activity; and accommodation to future changes in the system as a result of both natural processes and global warming. Conservation and management efforts have incorporated international recognition of the unique features of the bay, regulatory action by two levels of government, and a substantial component of community-based management.

Twenty-three marine species that are associated with the Bay of Fundy are recognized by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). These species include five mammals, 11 fish, and seven birds (Table 1). (Criteria for assessment and designation as Endangered, Threatened, or of Special Concern may be obtained from: http://www.cosewic.gc.ca/). Programs are in place for the protection and recovery of those species classified as Endangered and are being developed for other species in the COSEWIC list. The North Atlantic right whale is one of the world’s rarest species, with 2010 surveys indicating only about 450 animals remaining (see http://www.fisheries.noaa.gov/pr/species/mammals/whales/north-atlantic-right-whale.html). Prior to the expansion of the whaling industry in the eighteenth and nineteenth centuries, right whales roamed the North Atlantic but are now encountered only along the western side from Florida to the Bay of Fundy. At least half of the population appears to utilize the Outer Bay of Fundy and Roseway Basin during summer months. Because ship strikes in the Bay of Fundy region were a major cause of right whale mortality, a conservation area was established for the Outer Bay and the international ship traffic lanes were moved to minimize the overlap with right whale summer feeding areas, which are associated with major mixing zones near Grand Manan Island. This has reduced ship mortality, but significant problems remain with whale entanglement in fishing gear – especially trap lines set by lobster harvesters.
Table 1

Bay of Fundy species assessed and designated by COSEWIC as at risk (Source: http://www.cosewic.gc.ca/eng/sct0/rpt/csar_fall_2014_e.pdf)

Common name

Species

Status

Last assessed

North Atlantic right whale

Eubalaena glacialis

Endangered

2013

Northern bottlenose whale

Hyperoodon ampullatus

Endangered

2011

Harbor porpoise

Phocoena phocoena

Special concern

2006

Fin whale

Balaenoptera physalus

Special concern

2005

Sowerby’s beaked whale

Mesoplodon bidens

Special concern

2006

Porbeagle shark

Lamna nasus

Endangered

2014

Atlantic salmon

Salmo salar

Endangered

2010

Striped bass

Morone saxatilis

Endangered

2012

Cusk

Brosme brosme

Endangered

2012

Spotted wolffish

Anarhichas minor

Threatened

2012

Atlantic sturgeon

Acipenser oxyrinchus

Threatened

2011

American eel

Anguilla rostrata

Threatened

2012

Atlantic cod

Gadus morhua

Special concern

2010

Winter skate

Leucoraja ocellata

Special concern

2005

Shortnose sturgeon

Acipenser brevirostrum

Special concern

2005

Atlantic wolffish

Anarhichas lupus

Special concern

2012

Piping plover

Charadrius melodus melodus

Endangered

2013

Roseate tern

Sterna dougallii

Endangered

2009

Least bittern

Ixobrychus exilis

Threatened

2009

Peregrine falcon

Falco peregrinus anatum

Special concern

2007

Harlequin duck

Histrionicus histrionicus

Special concern

2013

Barrow’s goldeneye

Bucephala islandica

Special concern

2011

Yellow rail

Coturnicops noveboracensis

Special concern

2009

The Bay of Fundy is replete with environmentally sensitive areas, some of which have been designated for conservation or special management under international, national, and provincial programs or reserved by nongovernment organizations. There are two UNESCO Biosphere Reserves: the Fundy Biosphere Reserve in the Upper Bay of Fundy and the Southwest Nova Biosphere Reserve which includes mainland and islands of the Outer Bay. UNESCO World Heritage status has been awarded to Joggins, NS and Parrsboro, NS in the Upper Bay for their important Jurassic fossil beds, and to Grand Pré, NS, also in the Upper Bay, for the 400 year agricultural history based on marshland conversion. Three sites in the Upper Bay are recognized under the Ramsar Convention on Wetlands and form part of the Western Hemisphere Shorebird Reserve Network because of the important role played by invertebrates of the intertidal flats in supporting migratory shorebirds. In addition to these high profile international designations, there are more than 20 other sites that receive some form of protection as national or provincial ecological or historic marine sites, including wildlife reserves, marine protected areas, and bird sanctuaries (cf. Jacques Whitford 2008; AECOM 2010).

Threats and Future Challenges

In spite of the protective measures outlined above, the Bay of Fundy is very much a “lived in” ecosystem, with a variety of resource uses and human impacts that provide significant challenges for management. These include: fisheries for shellfish and finfish; aquaculture for marine plants, shellfish and fish; international shipping; tourism and recreation; channel dredging and spoil disposal; dam and causeway construction; and mining. The huge tides of the bay have naturally stimulated interests in renewable energy. For the last century proposals for generating electricity from tidal movements have been examined repeatedly, and one tidal generating station exists: the 20 MW Annapolis Tidal Generating Station that was opened in 1985 (Daborn and Redden 2009). Present renewable energy interests are based upon tidal in-stream technologies that appear to have fewer environmental risks than tidal range approaches (ATEI 2013). A major test site for large, commercial scale devices (FORCE: Fundy Ocean Research Center for Energy) has been established at the entrance to Minas Passage, and several other sites are under consideration for installation of arrays of tidal stream generators of varying size.

Managing human activities in such a diverse coastal ecosystem is challenging. Human interventions such as the modification of the bay’s natural morphology by marshland conversion, dredging, damming of rivers, and causeway construction have often triggered changes in critical physical processes that may continue for years. The dynamic nature of the nonlinear processes associated with tidal movements means that even subtle changes may have significant effects over the whole system and may take years to become apparent. As more understanding of the bay ecosystem is achieved, the value of such interventions is being reassessed, and in response to pressure from local communities, efforts are under way to explore the potential for reversing the negative effects, particularly of dam and dyke construction. The Petitcodiac River Causeway, constructed in 1968, is one of three large causeways built across major estuaries entering the Bay of Fundy for highway crossing and flood control purposes. Because of the extreme turbidity of the estuary (<30,000 mg/L) associated with 11 m tides, rapid and massive deposition of sediment occurred on the seaward side of the dam, eliminating the tidal bore and severely impeding upstream migration of anadromous fish such as salmon, alewife, and shad. In 2010 because of public pressure the causeway was opened again, allowing tidal water to flow upstream past the city of Moncton, NB. Within months, a substantial tidal bore returned, and it is anticipated that the sediments deposited will be remobilized over time as the estuary adjusts to the change.

Appreciation of the high productivity of Fundy salt marshes is the result of research during the last decade. The progressive conversion into agricultural land of more than 80% of the marshes over the previous four centuries provided some of the most productive farmland in Atlantic Canada, yielding large quantities of hay, grains, and vegetables. However, global competition in agriculture, shifts in demand, climate change, costs of dyke maintenance in the face of rising sea level and tidal range, and urban expansion onto dyked lands have all contributed to a re-evaluation of the benefits of exchange of marshes for dyked land. Dykes destroyed by storm surges have not always been repaired, and recent research into the process of recovery when previously dyked land has been allowed to “go out to sea” again is actively under way at the Beaubassin Research Station, a joint venture between Ducks Unlimited Canada, the Irving family and Acadia University, and by local universities.

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© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.Acadia Centre for Estuarine ResearchAcadia UniversityWolfvilleCanada

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