What the Warm Winter Means for the Bay

Anybody's guess really:

The crabs are stirring early in Virginia, rockfish could spawn sooner and algae blooms could be worse than usual because of an extremely mild winter that kept water temperatures above average, scientists and watermen say. Bird watchers, meanwhile, can look forward to earlier arrivals, with many birds arriving one to three weeks early, according to the American Bird Conservancy.

No one knows for sure what will happen, though. Crabs, for example, are moving earlier, but where they will be caught isn’t as clear. That’s because while warmer temperatures get them going, the saltiness of bay water affects where they turn up, Fegley said.

It doesn't matter where they go; the watermen will be there to catch 'em.

Thomas Miller, a fisheries expert at the University of Maryland Center for Environmental Studies who leads an annual assessment of the bay’s blue crab population, said one thing is certain: fewer crabs died of cold this winter. Nearly a third of the bay’s crabs were lost last winter to cold and Miller estimated less than 5 percent succumbed this winter.

For fish, it all depends on where they spawn, Miller said. Those that spawn offshore, such as flounder and menhaden, do better during warmer winters. Those that come into the bay to spawn, like striped bass, river herring and perch, do better during colder winters, Miller said. That’s because warm winters increase movement of ocean waters for offshore spawning, which helps larvae move about. For fish that spawn in the bay, the difference between a colder winter and warmer spring temperatures is thought to provide a stronger signal for them to head into the bay, Miller said.

It's long been known that cooler winter and springs favor the spawning of stripers, herring and perch.  I think the milder winters also produce higher salinity further up the bay, which is not favorable to the anadromous fish.

The warm water made it harder to catch striped bass once they got into the bay because the fish “get a glaze over their eyes,” when the water is cold, said Kevin Tarleton, 18, a waterman from Tilghman.

“If they got glaze over their eyes then they can’t see the net,” Tarleton said.

In my experience, Striped Bass may not see as well in cold water.  In my experience, until the water gets above about 60 F, Stripped Bass stop biting as soon as the sun goes down, but will feed quite nicely at night at warmer temps.  My guess?  Vision is a chemical reaction, and it slows down at colder temperatures.  I don't believe the "glaze" theory. 

Bob Orth, a Virginia Institute of Marine Science researcher who works on an annual survey of bay grasses, said he is wondering what the consequences of a warm winter will be.

“We always think we know the answer, then nature comes along and puts a little twist into it,” Orth said.

What he said...