Uncertainty in Stock Assessments Impacts Harvest Rates

Dr. John Wiedenmann, Dr. Olaf P. Jensen

Research Abstract

Overfishing continues for many stocks in the New England groundfish complex despite efforts to constrain harvest rates and rebuild populations. We evaluated the magnitude and sources of scientific uncertainty in catch targets for groundfish and found that since 2004 annual harvest rates have been 151% above the target while catches have been 29% below the target catch, on average, resulting from overly optimistic catch targets for the majority of stocks. Multiple sources of scientific uncertainty contributed to this overestimation, but the largest contributor was overestimated abundance. By evaluating sequential assessment estimates, we found previous assessments frequently overestimated terminal abundance. Additional uncertainty in catch targets resulted from recent recruitments often being below historical levels. The net effect of overly optimistic catch targets and declining recruitment is that rebuilding has been sluggish and potential yield (and revenue) has been forgone for many stocks. The causes of the overestimation of stock abundance and declines in recruitment remain unknown, but because these patterns were widespread, there may be common mechanisms in the region influencing assessment estimates and stock productivity.

The research was funded through the New England Fishery Management Council’s budget.

Read full research document here pdf.

CONTENTS

Global Lobster Trade

When the Civil War Came to Maine

Editorial – You Watch My Back: Season 40

Uncertainty in Stock Assessments Impacts Harvest Rates

Letter – Commissioner’s Letter on LD575

If Lobster Landings Fall, Profits Could Too

Widely-Used Marine Seismic Gun Negatively Impacts Zooplankton

Hydrographic Surveys in Penobscot and Jericho Bays

Shrimp Fishermen, Shut Out For Now, Weigh in on Future Management Measures

2017 Seafood Throwdown Schedule

DOC Decision May Impact ASMFC’s Ability to Conserve Atlantic Coastal Fisheries

Dept. of Commerce
Picks Council Seats

Where New England’s Catch Goes and Why It Matters

Marine Species Distribution Shifts Will Continue Under Ocean Warming

Given the Right Tools, Fishermen Perform Data Collection

Nicholas Walsh – Fiduciary Duty

Stonington Races: Big Turn Out on a Great Day

2017 GMC Double Cab 4x4 at Winter Harbor Lobster Boat Race, August 12, 2017

24th Year for Stonington Races

Codfather Attempts to Leverage Permits and Boats

NMFS Fishing Vessel Capital Construction Fund Procedure Changes

From Beaches to the Bottom of the Sea, Microplastics Everywhere

Macroalgae Cultivation

The Voice of Safety – Life Saving Technique Easy and Available

Meeting

Life Jacket Project!

Hampton, NH Fisherman Takes Case to US Supreme Court

Groundfishing and Lobstering on the Same Trip

Data Yields Trajectory of Maine’s Coastal Fisheries at PMM

Request for Information on Offshore Oil & Gas Leases

2017 Maine Lobster
Boat Racing Schedule

Lee Wilbur – Learnin’ To Love Fishin’

Classifieds

Book Review – Phillip Barter, Maine Master

Back Then – Shay’s Tent