Managing to make sense of species management
By ON THE OUTDOORS http://www.baltimoresun.com
The Young of the Year striped bass survey, which the Department of Natural Resources has used for more than a half-century to measure spawning success, showed a slight decrease this year from the long-term average. Biologists placed the index at 7.9; the average is 11.7.
Tom O'Connell, director of the Fisheries Service, calls it "a decent year" that is "well within the normal range of expectations."
At 3.2, last year was considered a recruitment failure. Three consecutive failures trigger mandatory conservation measures from the Atlantic States Marine Fisheries Commission.
But that's the nature of the beasts. Wet weather, cold temperatures and salinity are just some of the factors that tip the index from good to bad. In 2002, it was 4.73. The next year, it was 25.75. A dry spring in 2006 dropped the index to 4.3. In 2007, it rebounded to 13.4.
Fortunately, the Chesapeake Bay has produced some eye-popping numbers in recent years. In 2001, the index was 50.75, the second highest on record, and 2003 was about half that. Those older fish are about to enter the spawning stock.
"Those are years of incredible abundance where you can fish off one class for a decade," says Eric Durell, the biologist who oversees the survey.
The state has 22 sampling sites in the four primary spawning systems: the Upper Bay and the Choptank, Nanticoke and Potomac rivers. Once a month from July through September, biologists take a seine net and see how many fish born that spring they can scoop up in two passes. The index number is derived from the average number of juvenile fish caught in 132 hauls of the net. So if there are 132 fish caught in 132 samplings, the index number is 1.
Durell notes that from 1959 to 1972, the period before the steep population decline, only four year-classes were above average. Since the lifting of the striped bass fishing moratorium in 1990, 10 year-classes have been above average.
"We're living pretty high off the hog," Durell says. "We've got a lot of good things going for us."
The striped bass numbers will certainly be used in the debate when the Sport Fisheries and Tidal Fisheries advisory commissions hear a request from O'Connell to regulate catch-and-release activity that precedes the April-May trophy season.
Specifically, the Fisheries Service has proposed to limit the number of lines on a boat to six, prohibit the use of bait and dropper, or "stinger," hooks, and require barbless hooks.
More than 75 percent of the East Coast's striper population began life in the Chesapeake Bay and its tributaries. Egg-laden females cruising up the coast from warmer waters arrive here early each spring to rendezvous with the boys.
State fishing regulations put spawning waters off limits during that time, but a growing number of recreational anglers - perhaps hoping to break their cabin fever - go out and catch and release the females before the start of the season. The Fisheries Service says there's been a fivefold increase in fishing trips in March and April during the past seven years.
The early birds contend that there's no harm done when water temperatures are low and the fish are released quickly. There is science to back up that claim: The mortality rate on shallow-hooked, expertly handled fish is just below 1 percent.
However, anglers have made themselves more efficient fishing machines, with electronic fish finders and by rigging their boats with so many rods that they look like Sputnik. And from the looks of the photos e-mailed to The Baltimore Sun, it appears there are a lot of folks who don't know how to safely handle a large fish.
Plus, one potentially significant question remains unanswered: Does catch-and-release fishing stress the females to the point that they don't spawn?
The answer will probably elude biologists since penned fish - the kind used in experiments - refuse to spawn naturally.
Why take a chance? The restrictions being proposed for March 1 until the start of the trophy season on the third Saturday in April are pretty innocuous and in keeping with good fishing practices.