On Jan. 24, the editorial board of the BDN ran an insightful editorial addressing failed fisheries regulations and the uncertain future of depleted fisheries stocks. A major point of the commentary was that we need to take a more integrative approach to the management of our marine resources, one that respects the interdependency of species and the uniqueness and diversity of habitats.
Our extremely productive coastal estuaries are especially vulnerable to overexploitation because of their proximity to human populations. Decades, if not centuries, of man-made acid rain, toxic runoff, over harvesting and development have resulted in decreased diversity and diminished populations of marine life. This is clearly evidenced by recent closures, shortened seasons and reduced quotas of many statewide fisheries, including shrimp, elvers, urchins, cod, scallops, smelts and sand worms, to name a few.
There is a generational baseline shift in our perception of what constitutes a normal and healthy environment. A recreational fishing trip today is likely to yield a catch that is smaller in size and number than when our deceased relatives were photographed holding their fishing trophies — and today’s catch also may be toxic to the extent that we are advised to limit human consumption to avoid serious health problems.
Instead of dedicating resources to researching and restoring these habitats to the historical higher standards, the state Department of Marine Resources’ focus seems to be on developing new aquaculture industries without much regard to the native and migrating wildlife. Filling sensitive or vulnerable habitats with high-density monoculture seems to be today’s mantra. Why not instead make a significant effort to re-establish healthy historical eel grass, kelp and rock weed habitats, which serve as nursery areas for a wide variety of commercially and recreationally important marine and estuarine species?
In the long run, a better solution for the environment and those seeking new opportunities would be to commit more resources to acquiring essential ecosystem baseline data. With such data, better long-term management decisions could be made based on understanding seasonal carrying capacities and the interdependence of indigenous species, identifying impacts of climate change and growing acidification, mapping all the various unique habitats and more.
During two community discussions last year organized by the Department of Marine Resources in Penobscot to address oyster aquaculture expansion concerns on the Bagaduce River, there was an eerie absence of opinions from other relevant state and federal agencies, land conservation trusts with coastal holdings and marine scientists. The Department of Marine Resources, in an apparently unchallenged leadership position, seems perfectly comfortable moving forward with oyster production-driven science rather than on broader ecosystem investigation and improvement. Why not work harder to restore or enhance the function of these vulnerable ecosystems so they support a broad diversity of species and resource uses in lieu of creating artificial ones featuring the dominance of one species?
The aquaculture industry enthusiastically claims that bivalves improve water quality through filtering but rarely acknowledges the danger extensive bivalve grazing causes to the base of the food chain. As more aquaculture leases are granted, we should become increasingly concerned about the potential for exceeding carrying capacity.
Every day a single bivalve can filter up to 50 gallons of seawater and ingest more than 100,000 molluscan and crustacean larvae, copepods, fish eggs and juvenile annelid worms. Many aquaculture leases grow oysters in densities of 400,000 per acre. On a 25-acre lease, that’s 10 million oysters, each one filtering up to 50 gallons on a good day.
Before more of these estuaries become filled with expansive aquaculture, we must take a cumulative look at potential overgrazing of the base. Macro zooplankton and juveniles of commercially important species depend on this food source, too. Larger predators feed on these, and so it goes on up the food chain. Until reliable data are available, it is unclear how aquaculture on an expanding scale would affect juvenile invertebrate and fish populations and alter local food webs.
The precautionary principle is a method sometimes used to minimize potential damage to the environment by cumulative human activity. In the case of the Bagaduce River, this principle is particularly relevant considering the lack of existing scientific research regarding the impacts of aquaculture. Before we fill every oyster-suitable nook and cranny of the Bagaduce River, let’s pause and take a broader, more comprehensive management approach to this unique, publicly owned resource.
Tom Stewart of Penobscot is an avid kayaker, fisherman and seascape artist who has lived on the Bagaduce River for 30 years.