Oysters need salinity at 8-10 parts per thousand at minimum to survive, Tobash Alexander said. Normally at this time of year, the brackish water Horn Point brings in from the Choptank River would be 10-12 parts per thousand. "There have been other years where there have been challenges. None have lasted as long as this," said Don Webster, an expert on commercial aquaculture development at the University of Maryland. The bay's salinity still hasn't recovered, with data from mid-June 2019 showing salinity just approaching the historical average range, the Virginia Estuarine and Coastal Observing System reports. The runoff and flooding brought excess nutrients and sediments into the waterways feeding the bay, and the bay's overall health suffered significantly as a result, the Chesapeake Bay Foundation's 2018 "State of the Bay" report states.Īs northern tributaries injected fresh rainwater into the bay, the amount of salt dissolved in the normally brackish bay water became severely diluted. With the ground unable to take any more, the fresh water flowed straight into the rivers. With so much rain, traipsing around in nature in the last year could be like walking on a soaked sponge. Much of the Chesapeake Bay watershed received 60-80 inches of rain during that time period, about 110% to 150% of normal, according to the National Weather Service. Importantly, the intensity was consistent, with Mother Nature delivering above-average rainfall in 10 of the last 12 months. While weather each year on the bay varies, from July 2018 through June 2019, the bay watershed experienced more rain than has been recorded since record keeping began. It's got to be something with the water.” Walking on a sponge Everything we’re doing is what we did last year, what we did the year before and the year before that. "There’s something that, for some reason, our collective brains can’t figure out when we have not changed a thing. “We’ve put our pride to the side we need help, " Tobash Alexander said. Reaching out to colleagues and friends in various research fields for help hasn't provided any answers, she added.
This year's failed production has been humbling, Tobash Alexander said. The absence of spat this year is a looming specter over the oyster industry, which will begin to face harvesting difficulties in about 18 months to three years (the amount of time it takes an oyster to grow to a harvestable size). Oyster seasons can be variable, but this is the first time in 15 years that the hatchery will likely fail to meet its annual goal of putting 500 million spat-on-shell out into the bay, Tobash Alexander said.
Researchers are quickly trying to discover the cause of the problem before the chance to produce more larvae has passed. That's 200 times less than last year, and almost 300 times less than the year before, said hatchery manager Stephanie Tobash Alexander, a senior faculty research assistant at the University of Maryland. So far this year, the Cambridge hatchery has produced only about 6.5 million oyster spat-on-shell.
0 kommentar(er)
