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
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