State considers life raft for beleaguered oysters

August 10, 2017 GMT

Texas’ oysters lead a tenuous life even in the best of times.

The past decade has seen some of the worst of times for these invaluable marine mollusks whose population ups and downs largely hinge on the vagaries of weather and, increasingly, human actions

Much of the state’s approximately 48,000 remaining acres of oyster reefs, essential to the health, vitality and diversity of coastal ecosystems, crucial natural bulwarks against storm surges and the raw stock fueling a multimillion-dollar commercial fishery, have endured a decade of misfortune and devastation through an unlucky combination of natural and human-caused factors.


“The result is the oyster resource is facing serious challenges,” Lance Robinson, deputy director of coastal fisheries for Texas Parks and Wildlife Department, said during a May briefing before the agency’s commission.

The focus of that briefing - outlining a package of proposed changes in regulations governing commercial and recreational harvest of oysters that includes permanently closing about 6.6 percent of the state’s public oyster reefs to all harvest and imposing further restrictions on commercial harvest - and a bill passed earlier this year by the Texas Legislature aim to give the state’s oysters the breathing room they need to recover from their current dissipation and protect their ability to rebuild numbers that naturally see ups and downs.

The past decade has seen nothing but downs for Texas’ oysters. That tumble came on the heels of what had been a generally stable period in the 1990s and early 2000s where oysters reproduced and grew at fairly normal rates but still slowly lost ground because of vigorous commercial harvest that had Texas providing about 20 percent of the nation’s commercial harvest of eastern oysters.

“But everything changed pretty much overnight, September 13, 2008,” Robinson said.

A tough stretch

Hurricane Ike, which slammed into Galveston Island that day, sent a wall of silt-laden storm surge into Galveston Bay. That silt settled over open-water oyster reefs that, because of persistent commercial harvest over the years, did not rise as high off bottom as they would have if the live oysters growing on their surface had not been relentlessly dredged. The silt covered the reefs, smothering them.

At least half of the oyster habitat in Galveston Bay, which accounted for 90 percent of the commercial oyster harvest in Texas, disappeared overnight. The loss of Galveston Bay’s oyster reefs to Ike sent the state’s highly mobile commercial oyster fleet to other Texas bays, significantly increasing harvest in those areas.


In 2010, the Deepwater Horizon tragedy and resulting oil spill saw commercial oystering in all Gulf states other than Texas closed or severely restricted. That put additional pressure on Texas oyster reefs to feed the oyster market.

Then came drought. Texas endured record-setting drought from 2011 through 2015. The lack of freshwater inflows into Texas bays from the state’s desiccated rivers resulted in salinity levels in bays spiking to levels as much as three times normal. Those increased salinity levels allowed a pair of oyster predators to swarm to reefs.

The predators - a snail known as an oyster drill and a parasite called dermo - usually are not a major problem for live oysters as the snail and microscopic parasite require high-salinity water to survive. Oysters evolved over millennia to locate their reefs in waters of moderate salinity, out of reach of the salinity-loving predators. With the drought-caused spike in bay salinities, the parasites devastated live oysters.

Then came the floods. In 2015 and 2016, flooding in much of Texas sent freshwater runoff pouring into bays for months on end, dropping salinity levels to zero in many reefs for weeks or even months. Oysters are hardy creatures and can survive a few days in freshwater. But after a week, they begin dying. And they died by the millions in the 2015 and 2016 floods, with the flooding also destroying the oysters’ 2016 spring spawning effort.

Shrinking harvest, reefs

As the amount of live oysters decreased over the decade, commercial harvest followed, falling from 6.9 million pounds in 2003 to 2.5 million pounds in 2016. But commercial oyster fishing pressure remains intense. Texas since 2005 has had a limited-entry commercial oyster fishery with the number of commercial licences capped at 2005 levels - 557 commercial oyster boat licenses and 465 oyster boat captain licenses.

During the Nov. 1-April 31 open oystering season on public reefs, those commercial boats and crews fell on the shrinking number of open reefs and quickly dredged them nearly bare of oysters meeting the 3-inch minimum size set by the state. It takes an oyster about two years to grow to that 3-inch minimum.

Beginning in 2015, TPWD, with the blessing of the commercial oyster industry, began closing public reefs to harvest when sampling indicated most of the legal-size oysters had been taken. That put more pressure on the ever shrinking number of open-to-harvest reefs. One 30-acre public reef in Galveston Bay that TPWD had spent $1 million restoring was swarmed by more than 50 commercial boats when it was opened to public harvest in January 2016 and stripped of all legal oysters within two days.

Near the end of the 2016-17 oyster season, only a half-dozen of Texas’ three dozen public oyster zones remained open to harvest. The rest had been closed because they were deemed overharvested.

Those commercial oyster operations, driven by shrinking open-water public oyster reefs in traditionally harvested areas such as Galveston Bay, expanded their operations to areas that had previously been seldom worked or lightly harvested. That included the shallow waters along bay shorelines and reefs in shallow minor bays along the coast. In some of those bays, the shallow water forced commercial oyster harvest to shift from use of dredges to manual harvest where workers waded on the shallow reefs, using hammers to break live oysters from the reefs.

That “invasion” of commercial oyster into small, shallow bays and the damage that activity inflicts on the bay’s ecosystem has triggered a considerable public outcry to protect those previously lightly harvested areas. Also, the high harvest pressure on public reefs and the high demand for commercial oysters saw some commercial boats opt to violate Texas by taking too many undersize oysters.

Under current Texas law, a commercial oyster boat’s harvest of oysters can include no more than 15 percent undersize oysters or “dead” oyster shell. Over the past few years, Texas game wardens have issued scores of violations of this regulation, with some sacks of oysters checked on oyster boats holding as much as 95 percent undersize oysters. Violating the regulation is a Class C misdemeanor, with a fine of $25-$500. And only the boat’s captain is liable for a citation; the crew are exempt from being cited. Commercial oyster harvesters this past year were getting about $40 per sack (about 110 pounds) of oysters at dock side, with boats allowed to harvest 50 sacks per day. The small fine is not much of a deterrent to stay legal.

New legislation

This year, the Texas Legislature waded into the oyster issue, passing HB 51, a multifaceted law that addresses some of the issues tied to the commercial oyster industry.

The bill creates a license buy-back program that will use part of commercial fishing fees to buy and “retire” commercial oyster licenses, with the aim of reducing the number of commercial oyster boats on the water.

It also mandates commercial oyster dealers return and distribute back into the bays an amount of oyster shell or other approved material such as river rock equal to at least 30 percent by volume of the oysters they purchase, or pay a fee to TPWD to buy and distribute the material. That oyster shell or other had material - termed “cultch” - is the hard substrate on which oyster “spat” (microscopic larvae) attach and grow. A lack of cultch is a limiting factor in oyster reproduction.

The bill also makes all persons aboard a commercial oyster boat subject to citation for violations of oyster regulations and substantially increases penalties for violations of the undersize oyster rules, including making egregious violations (more than 30 percent undersize) a Class B misdemeanor which subjects those cited to arrest. It also allows for a 30-day suspension of a commercial oyster license for some violations.

HB 51, which was signed into law in June, also requires all persons commercial harvesting oysters hold a commercial oyster fisherman’s licenses, something not now required.

Texas Parks and Wildlife Department is proposing a package of regulation changes that would impose further restrictions on harvest - commercial and recreation - of oysters.

The proposal would reduce the daily limit for commercial oyster boats from 40 to 20 and prohibit commercial oystering on Mondays - commercial oystering is currently prohibited on Sundays. And it would reduce the allowable percentage of undersize oysters or dead shell from 15 percent to 5 percent.

Other measures

TPWD also proposes closing seven minor bays - Powderhorn Lake, Christmas, Keller, Carancahua, St. Charles, Hynes and South bays - to all oyster harvest, commercial or recreational.

The agency also proposes prohibiting all oyster harvest within 300 feet of a shoreline. The move is aimed at protecting the intertidal oyster reefs in these areas. Those intertidal reefs have been shown to be some of the most valuable habitat in the bays, serving as home and sanctuary for a stunning diversity of marine life, including finfish and crabs, as well as protecting shorelines from erosion and blunting the damage caused by storm surges. Recent research estimates the value of the ecological services these intertidal oyster reefs provide at as much as $244,000 per acre.

The closure of the seven minor bays and the 300-foot buffer along all bay shorelines would affect about 3,200 acres of oyster habitat, or about 6.6 percent of the 48,000 acres of public oyster reefs in the state, TPWD officials said.

At its Aug. 24 meeting in Austin, the Texas Parks and Wildlife Commission will hear public comment on the proposals and vote to adopt, modify or reject all or part of the package. Any rules adopted would be effective at the Nov. 1 opening of the 2017-18 oyster season.