Nearly half of Gulf oyster harvesting areas are closed after summer deluge and active hurricane season

Weather & Traffic In-Depth

AUSTIN (KXAN) — November through April is harvesting season for Gulf oysters, and the season so far is off to a rough start for commercial fisheries. Meteorologist Sean Kelly spoke with Zach Olsen of the Texas Parks and Wildlife Department about the problems folks are having.

Olsen is the ecosystem leader for the Aransas Bay system in Rockport in the Coastal Fisheries Division. He explained what’s at the center of causing a poor start to the season.

“The bigger impact of oyster mortality tends to be rainfall and salinity…we saw quite a bit of rain throughout the summer, July, August, into September even,” Olsen said.

The majority of Texas oysters are harvested in our four Central Gulf Coast bays, starting up from Galveston Bay. Nearly 70% of the oysters harvested in Texas come from Galveston Bay alone. Galveston, on average, sees roughly 12 inches of rain during the summer months. This past season, however, the area far exceeded that with a whopping total near 17 inches.

“We’ve seen quite a bit of oyster mortality, due to that freshwater inflow. So that starts off the oyster season at a lower abundance than typical.” Olsen said. Runoff not only changes the salinity, but can carry pesticides and bacteria with it — all inhibitors of oyster growth.

So far this season, TPWD has had to close almost half of the state’s 29 harvest areas it manages. Runoff from our wet weather isn’t the only culprit, though. Storm surge from another active hurricane season that’s still reeling from damage of year’s past is also to blame.

“Hurricane Ike had a huge impact on oyster reef availability… Hurricanes often cover up reefs with sediment. Hurricane Harvey had some impacts especially in the Galveston and Rockport area,” Olsen said.

Harvey dropped over 30 inches of rain on the Houston metropolitan area, and the associated runoff dropped salinities to near-zero, resulting in widespread mortality of oysters in Galveston Bay. They are still recovering from Harvey’s impacts four years later.

Olsen also said the nature of fishing out oysters, removing more and more shells, that would have otherwise been a surface area for more oysters to spawn has a major impact. Space can also be limited as oysters compete with mussels for nutrients.

“The availability of hard structures for those oysters to settle on, oysters need oyster reefs so they can settle and grow,” Olsen said.

TPWD did a lot of preseason work leading up to the closures. It involved sampling what areas they should open or close for harvesting. The process involves dragging a dredge or steel basket behind a boat for a set amount of time.

“Then we pull that up, count and measure the oysters,” Olsen said. “We use that to essentially measure what the oyster population is in a given area and if it meets certain thresholds we have for opening or closing the area.”

TPWD will continue to reassess its closed areas throughout the season to see if they can reopen at any point. At the same time, the department will continue its work on restoration.

“Parks and Wildlife is involved with oyster reef restoration, where we will actually take shells provided by commercial oyster fishermen,” Olsen said. “We will replace that shell or other hard materials into the water so that those oysters can settle.. so providing a habitat for those oysters.”

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