River herring discard estimation, precision, and sample size analysis

"A total of 106,455 pounds (149% CV) of river herring was discarded during the 12-month period from July 2007 through June 2008. The river herring discards occurred primarily in the New England small mesh otter trawl fleet, and to a lesser extent in the New England shrimp trawl, New England large mesh trawl and Mid-Atlantic small mesh otter trawl fleets. The total number of sea days (9,002 days) needed to achieve a 30% CV for river herring discard estimates is 40% less than those needed for the 15 Standardized Bycatch Reporting Methodology (SBRM) species groups (15,125 days). On a fleet by fleet basis, the number of sea days needed to achieve a 30% CV for river herring discard estimates was either the same or less than for the 15 SBRM species groups with the exception of one fleet: New England large mesh otter trawl where the river herring species group needed 2,827 more sea days than the 15 SBRM species groups. The low number of observed trips in the Mid-Atlantic gillnet fleets and the limitations of observing all discards associated with the fishing practices of the high-volume fisheries are two sources of uncertainty in the discard estimation and sample size analysis"--Executive summary. by S.E. Wigley, J. Blaylock and P.J. Rago. "December 2009." Includes bibliographical references (page 7).