Overfishing and underfishing consequences for food security and economic value in U.S. fisheries

Michael Melnychuk, Jeannette Banobi, Ray HilbornSchool of Aquatic and Fishery Sciences

University of Washington

Worm et al. 2009, Science

Georges Bank

Trade-offs

B/BMSY

Biomass and fishing mortality reference points

F/F M

SYOverfished

Overfishing

Recent status of U.S. stocks

Regional medians

B/BMSY

F/F M

SY

Rank order of stock MSY in region

Alaska West coast Northeast coast Southeast coast

4

3

2

1

0Cum

ulati

ve y

ield

(mill

ions

t)

Maximum sustainable yield (MSY)

Equilibrium yield under current exploitation rate

Foregone potential yield

Cumulative multispecies yield

(commercial

landings only)

∑ ≈ 0.15 million t

Foregone potential yield

∑ > 3.5 million t

Rank order of stock MSLV in region

Alaska West coast Northeast coast Southeast coast

2

1

0

Cum

ulati

ve la

nded

val

ue ($

billi

on)

Maximum sustainable landed value (MSLV)

Equilibrium landed value under current exploitation rate

Foregone potential landed value

Cumulative multispecies landed value

(commercial

landings only)

∑ > 1.7 billion $∑ < 0.6 billion $

Foregone potential landed value

Intercept

Ex-vessel price

Landings

Under rebuilding ?

Bycatch limits for exploited species ?

Bycatch limits for non-exploited species ?

Typically caught incidentally ?

Low market demand ?

Factors affecting the degree of ‘underfishing’ or overfishing

Factors

F/FMSY

for stocks experiencing

overfishing

Response variable

for stocks experiencing ‘underfishing’

{ Region = random effect }

Generalized linear mixed effects model

Coefficient estimate

Effect on F/FMSY for stocks

experiencing ‘underfishing’

Intercept

Ex-vessel price

Landings

Under rebuilding ?

Bycatch limits for exploited species ?

Bycatch limits for non-exploited species ?

Typically caught incidentally ?

Low market demand ?

Effect on F/FMSY for stocks

experiencing overfishing

Factors affecting the degree of ‘underfishing’ or overfishing

no stocks

*

*

**

Underfishing /

Thank you to many fishery managers, stock assessment scientists, economists, social scientists, industry association representatives, and fishermen for patiently answering our questions.

And to all contributors to the RAM Legacy Stock Assessment Database

mmel@uw.edu

Recent status of U.S. stocks

B/BMSY

F/F M

SY

SAC red snapperOR cabezon

EC winter flounder

Georges Bank cod

SAC snowy grouper

GoMex gagGoMaine cod

sNE yellowtail flounder

5YZ Atlantic halibut

SWC cowcod

NEC silver hakeSWC rockfish: chilipepper,

shortbelly, splitnose,

greenstriped, blackgill,

greenspotted

Atlantic

butterfish

Widow rockfishAI walleye pollock

WC bocaccio

GoMex black grouper GoA rex sole

GoA dover soleBSAI flathead sole

WC English sole

nWC lingcodNE monkfish

GoA flathead soleBSAI Greenland turbot

Equilibrium

Equilibrium

Dynamic stock status plots at: depts.washington.edu/ramlegac

2009