For better or worse, farming oysters, like any fishery, is heavily influenced by “Mother Nature”. She makes an appearance in nearly all of my interviews, and is a feature player in the paper I’m currently working on. Despite best efforts, oyster farmers cannot dictate what Mother Nature will do, and are forced to respond and adapt, time and time again.
I’ve been in Alabama for two weeks now and oyster farmers here are waiting out Mother Nature so they can get back to harvesting oysters. Prior to my arrival, Alabama experienced one of its rainiest Decembers to date. The rain affected the region in a number of ways. It created a muddy campsite for me, but for oyster farmers it closed much of the Alabama coastline to harvest. All of the water has to go somewhere, and eventually it finds its way to the sea, passing through shellfish areas as it does. Six out of seven of the state’s shellfish growing areas have been closed since December 30, 2018.
Shellfish closures exist to mitigate risk to public health, because heavy rainfall means runoff from adjacent land. (Another reason to think twice about what you put on your lawn, dump outside, or don’t pick up, etc.) As a safeguard, oysters cannot be harvested and sold until the impacts of heavy rain have dissipated. This isn’t exclusive to Alabama; every shellfish-producing state enforces similar regulations. Here in Alabama, many farmers are going on 3 weeks of closure. Periodic closures are not atypical, but represent one more business challenge that oyster farms must prepare for. Farmers must plan for sporadic closures and hope that their buyers and markets can also accommodate the unexpected.
Closures are a regulatory response to heavy rainfall, but rain has other biophysical effects on oyster farms. Rainfall brings with it an input of freshwater into places like Mobile Bay, the outflow for the Mobile-Tensaw Delta and the endpoint for 6 major rivers. More freshwater means lower salinity. Oysters are resilient animals and are able to tolerate a range of salinities, oxygen levels, and temperatures, but salinity that is too low for too long can be stressful. A long period of extremely low salinity can lead to oyster death. Having spent many days on the brackish water of the northern Chesapeake Bay, I thought I knew low salinity oyster sites. I was stunned to find out that portions of Mobile Bay were approaching zero* a week after the last rainy day. (*Note: this freshwater result happened at low tide when water was moving out toward the Gulf of Mexico. At high tide at the same site, it’s very likely that the salinity would have been higher, influenced by the incoming Gulf water. But still, it was pretty darn fresh.)
I had the chance to visit the Bama Bay Oyster Farm and chat with Dottie Lawley and Bette Kuhlman as they waited out the harvest closure and low salinity associated with the most recent rain events. It was the salinity that weighed heaviest on their minds, knowing the effect a prolonged freshwater period could have on their oysters. As such, they’ve been treating their oysters accordingly. Typical oyster handling could prove too stressful to oysters already strained due to low salinity. At Bama Bay, they are trying to minimize handling to help get their oysters through this sub-optimal salinity period. At the same time, they can only wait so long before the effects of not working the gear take hold. The sooner the salinity rises, the better.
The rainfall that Alabama has experienced over the past month could have been even more detrimental to an oyster farm had they been using different gear. In other places, bottom-cages are used rather than cages that float near the surface (like the ones seen above). Bottom cages are submerged at most tides, and in certain areas are the preferred gear because they are less visible. Some oyster farmers put oysters directly on-bottom, without any type of cage or container. Being lower in the water column has its challenges, however, and the sediment that rain events bring could settle on bottom-dwelling oysters. In such a situation, an oyster farmer would need to weigh the costs of handling possibly salinity-stressed oysters with the additional stress (and potential suffocation) sediment could bring. [To be clear, this is not an argument for one gear type over the other. Each gear has certain benefits and constraints, and each operation needs to identify what is best for their site.]
Battling rainfall and all that it brings is par for the course for oyster farmers. In most cases, it involves many lessons learned, but over time successful farmers learn to read the oysters as well as the water, and do their best to prepare for the unexpected.
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