As the holiday season approaches and the weather cools, there is heightened interest in oysters for stews, stuffing or shucked on the half shell. I often hear colleagues, friends and family asking, “How are oysters doing in the Chesapeake Bay?” My quick answer is “OK.” The longer reply is that oyster habitat restoration is a work in progress (and we are making progress); oyster aquaculture is continuing to expand (meaning more varieties at your local oyster eatery); and the wild harvest is a mixed bag (with more harvesters competing for a limited resource).
The most recent scientific estimate of native oyster populations in Maryland’s portion of the Chesapeake Bay is approximately 0.3 percent of what it was in the early 1800s. Other references typically put the Baywide number at less than 1 percent of historic populations. These levels have been depressed for a long time.
But we’re starting to see some gains on the oyster habitat front, thanks to larger projects to rebuild oyster reefs and oyster populations as well as the long-term protection of sanctuaries. The Harris Creek, MD, tributary restoration project represents the largest scale effort of its kind, with 350 acres planted. An initial sampling of the first 100 acres planted there shows densities of 15 oysters per square meter (the minimum success threshold) on restored reefs, with more than half meeting the target of 50 oysters per square meter.
Maryland’s review of its oyster management plan, released in July, found that while it’s too early to tell the full story on sanctuaries, indicators for survival, abundance, biomass and size structure are generally stable or increasing.
In Virginia, the Lafayette River is nearing its restoration acreage target, with only 10 or so acres left to meet the goal for that tributary. The Lafayette has been closed to commercial harvest for decades, with intact relict reefs providing a source of brood stock. Local conservation partners have supported additional reef construction there. Large-scale oyster habitat restoration is also moving forward in other Bay tributaries: the Tred Avon and Little Choptank rivers in Maryland, and the Piankatank and Lynnhaven rivers in Virginia.
Oyster aquaculture is steadily increasing throughout the Chesapeake Bay, with Virginia’s 2015–16 total private (leased ground) production at 366,321 bushels (Virginia bushels hold 49 liters; Maryland bushels hold 46 liters, so this is the equivalent of 390,212 Maryland bushels), almost eight times Maryland’s 2015–16 production of 50,637 bushels. Virginia’s private aquaculture harvest now exceeds harvests from the wild fishery.
The Maryland Department of Natural Resources is working with the U.S. Army Corps of Engineers and the National Oceanic and Atmospheric Administration to streamline the permitting process for aquaculture to help further expand the industry in the Upper Bay. The Potomac River Fisheries Commission is piloting a cooperative where watermen farm oysters on designated bottom. New markets, new growing techniques and high consumer demand are driving the opportunity to increase the production of farmed oysters, particularly for the half-shell market.
For the wild fishery, there have been sharp increases in fishing pressure, represented by an increase in licensed harvesters. As the Bay Journal reported, “the number of watermen licensed or authorized to harvest oysters in Maryland grew from 570 in the 2007–08 season to 1,146 in 2015–16. (See Growing number of watermen could pose threat to oyster comeback, October 2016.)
The number of Virginia watermen who paid a user fee to harvest oysters on public bottom areas grew from 661 in 2013 to 1,124 this year. When Mother Nature produces more oysters during years with good spat sets, the response after a few years (when the oysters reach market size) is more fishing effort to reap the bounty — a roller coaster of relative abundance, followed by depletion.
The effects of increased fishing pressure are already evident in the recent downturn of oyster harvests. Although higher than the historic low harvests of the early 2000s, Maryland’s watermen harvested a total of 393,588 bushels in 2014–15, down from the previous year’s 422,382 bushels. Virginia saw a similar decline in their public fishery from 301,632 bushels in 2014–15 to 260,182 bushels last year. Early reports from harvesters signal a likely further drop in harvests from the public fishery this season.
To ensure a sustainable public fishery, consideration should be given to managing the fishing effort. Virginia’s Marine Resources Commission recently acted to stem the growing tide of harvesters by limiting the fishery to those who are currently paying the oyster resource user fee, with a goal of eventually reducing that number to 600. Under the Sustainable Oyster Population and Fishery Act of 2016, Maryland will complete a stock assessment of the oyster population and develop biological reference points for harvest. These management actions are a good first step; we should consider other models. Delaware Bay has an oyster fishery management program that’s been working well for several years with a quantitative survey, area management and an abundance-based quota.
Going forward, we need more-effective oyster management, including continued spatial allocation of Bay bottom for sanctuaries; increased restoration effort; expansion of aquaculture; and maintaining a wild harvest that promotes long-term growth and sustainability in the oyster population. As recommended at the February 2016 Chesapeake Bay Oyster Summit, we need to increase the use of alternative substrates in restoration to reduce the demand for dwindling supplies of oyster shell. The potential to use filter-feeding oysters to reduce Bay water pollution is emerging as a way to get more oysters in the Bay.
We also need to accelerate restoration. While we expect to have selected all 10 of the restoration tributaries called for in the Chesapeake Bay Watershed Agreement by next year, we have a long way to go to achieve the metrics established to measure oyster restoration success by 2025. But we’re on the road, using the best available science to learn from and inform the work.
Here’s to a Christmas future where oysters are plentiful, both as restored habitat in a cleaner Bay and served up with lemons and cocktail sauce at holiday parties.