ARCHIVED - Biological Environment

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HARVESTED SPECIES

Beyond doubt, the greatest overall public concern in reference to the state of the Northumberland Strait ecosystem has to do with declines in commercial fisheries virtually across the board (lobsters, scallops and herring most notably). The fact sheets, the Scarratt report, the GTA consultations report and the AMEC EOR are universally unequivocal in this regard. Declines are found in abundance of the principal exploited stocks, the landing statistics and the economic return to fishers. Declines in the central Strait area are generally greater than in the east and west. For example, GTA (2006:8) presents evidence to show that lobster landings in the central Strait declined by 61% between 1990 and 2004 while the declines in the eastern and the western Strait were 50% and 46% respectively. The decline in scallop landings over the 1990s is even more dramatic. According to AMEC (2006:4-11), landings declined by 56% and 88% in the two statistical districts within the Strait over the span of less than ten years.

Scientists have offered the Working Group well-studied hypotheses for these trends. In the case of lobster, an explanation can be found in part from the time frame upon which these changes are measured. For reasons not entirely clear, peaks in production and landings well above historical norms occurred in the late 1980s and early 1990s, and the subsequent decline is in line with the larger trend throughout the species range. However, the Working Group compared the landings today to the landings in those years, and concluded the central Northumberland Strait is in much greater decline than elsewhere. There is also a distinction to be made in regard to the trend in decline of scallop landings. Unlike the lobster fishery, which has been a mainstay of the local economy for almost a century, the scallop fishery only began to be exploited intensively in the mid-1960s. As is the case with many newly developed fisheries, this stock began to be fished at increasing intensity, and quite probably over-exploited, as new localized sub-stocks (scallop beds) were discovered.

It should also be noted that recent trends in spring herring harvest show a strong decline of this stock in the central Strait. Changes in other less important commercial species are not as dramatic nor quite as clear as is the case for lobster and scallop. However, in public consultations, past collapses of stocks such as white hake, haddock, skate and halibut (see also AMEC 2006:4-6) and concern over species for which there is little scientific data, such as winter flounder, smelts, silversides, oysters, clams and Irish moss, were prominent in the minds of fishers and other coastal community members.

The Working Group believes that there is more to the situation than can be explained by over fishing or conventional stock management models. Some members believe that there must be a link between these systematic declines and the observed changes in the environment itself. Scarratt (2005) agrees that there is some other factor at play in the Strait: “in the last dozen years or so, the [lobster] landings in the Strait have declined further, and are declining more rapidly than in the rest of the southern Gulf… The reasons why the Northumberland Strait has become significantly less suitable for producing lobsters should be investigated.”

OTHER AQUATIC SPECIES OF ECOLOGICAL IMPORTANCE

The Working Group recognizes that when considering the biological environment of the Northumberland Strait it is necessary to review both the commercial and non-commercial species. These species of ecosystem importance that lack immediately obvious economic value, have been neglected in past scientific investigations. Fortunately, in recent years this oversight has begun to be corrected through a series of annual DFO surveys in which all biota have been identified and quantified.

The Working Group sees the need to place particular emphasis on the importance of non-commercial aquatic species that may be keystone species upon which the ecosystem depends for stability and on which commercial species depend for forage.

The Working Group feels that the AMEC EOR does a thorough job of assessing the status of these species and also positions them well in the context of the roles they serve in the ecosystem. These biota are examined under the traditional taxonomic groupings: plankton (phytoplankton and zooplankton), benthos (infauna and epifauna), macrophytes (marine plants), macro-invertebrates (shellfish and lobster), finfish (pelagic, groundfish and migratory, including anadromous), reptiles, marine mammals and marine birds. But they also examine groups of special importance: species at risk and invasive species.

OTHER CONCERNS IN THE BIOLOGICAL ENVIRONMENT

Phenomena of note to the Working Group that add to the sense of concern expressed by the public are increasing frequency and geographic range of toxic algal blooms¹²; new and more extensive incidence of invasive species¹³; and an increase in abundance of seals and other predators (e.g. cunners, cormorants), though the latter observation is anecdotal and comes primarily from observations made during public consultations.

The Working Group notes again that an overlap exists between the chemical environment and the biological environment in a number of areas of special concern. First is the increased replacement of beneficial species with “nuisance species” (e.g. sea lettuce smothering eel grass) and also the increasing occurrence of fish kills and periods of anoxia in rivers, estuaries and bays. These are often a result of nutrient over-enrichment and eutrophication¹⁴. In addition, the Working Group has noted that the number, the duration and the geographic extent of shellfish bed closures has been constantly rising in the Northumberland Strait, as it has been all over Atlantic Canada¹⁵.

¹² Summary of Harmful Algal Bloom Events in Northumberland Strait; DFO Fact-sheet #2; Steven Bates

¹³ Invasive Species in Northumberland Strait; DFO Fact-sheet #3; Andrea Locke. 2005

¹⁴ Changes In Eelgrass (Zostera marina) In Southern Gulf Of St. Lawrence Estuaries; DFO Fact Sheet # 12; Andrea Locke

¹⁵ Scarratt, ibid.