Generic Harvest Control Rules for European Fisheries

Rainer Froese, Trevor A. Branch, Alexander Proelß, Martin Quaas, Keith Sainsbury & Christopher

Zimmermann

Accepted in Fish & Fisheries

Acronyms

• Bmsy is the biomass that can produce the maximum sustainable yield (UNCLOS, UNFSA)

• Fmsy is the corresponding fishing mortality• Blim is the biomass below which

recruitment is reduced and collapse possible

• Bpa is a biomass slightly above Blim but far below Bmsy

Cod, Eastern Baltic

0

100

200

300

400

500

600

700

800

900

1000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

SS

B a

nd

Lan

din

gs

(100

0 t)

Bmsy

Froese & Proelß Fish & Fisheries 2010

Bpa

Blim

Recruitment of Eastern Baltic Cod

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

900,000

0 100,000 200,000 300,000 400,000 500,000 600,000 700,000 800,000

SSB (tons)

Re

cru

its

(th

ou

sa

nd

s)

BpaBlim

European Fisheries are Mismanaged

• 24% are threatened by collapse (B < Blim)• 31% are near threatened (Blim > B < Bpa)• 45% are not threatened (B > Bpa)• But only 3-4 of these stocks have B > Bmsy

and F < Fmsy , i.e., comply with UNCLOS and UNFSA

• ICES since 2010 gives estimates of Fmsy but not MSY or Bmsy

• Less than half of the stocks are assessed

HCR 1: Reference and Trigger Biomass

The reference biomass Bmsy for the subsequent rules and reference points is the biomass that can produce the maximum sustainable yield.

This biomass also acts as a trigger when stocks fall below this level.

HCR 2: Target Biomass

The target biomass, to be achieved on average over approximately 5 years,

is 1.3 Bmsy.

The target biomass can be increased as required by economic, ecosystem or other considerations.

HCR 3: Limit Biomass

The limit biomass Blim, which is to be avoided with a high probability, is 0.5 Bmsy

A higher biomass limit may be set for species with low resilience to exploitation.

HCR 4: Total Allowable Catch

Fisheries are managed by a total allowable catch (TAC).

A maximum TAC is set for each stock so that the respective target biomass is maintained on average.

This maximum TAC may be taken as long as biomass fluctuations remain above Bmsy.

HCR 5: TAC Reductions

If the biomass falls below Bmsy, then the TAC is linearly reduced, as a function of biomass, to reach zero catch at Blim.

HCR 6: Mixed Fisheries

In fisheries where several target species are caught with the same gear, the maximum TACs for the respective stocks will be set such that the most sensitive stocks do not fall below Bmsy on average over five years, with a high probability of not falling below Blim.

HCR 7: Discard

No discard of commercially exploited species will be allowed, except for species with a demonstrated high discard survival rate.

HCR 8: Bycatch

Ecological risk assessment will be conducted on bycatch species and to assess potential damage to the environment caused by fishing, with respective measures to be taken to minimize risk.

HCR 9: Size structure

The mean size and age in the catch will be adjusted to minimize changes in age structure caused by fishing, and to reduce the effects of fisheries-induced unnatural selection.

Proposed Harvest Control Rules

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2

B /B msy

Y/M

SY

B msy0.5 B msy 1.3 B msy

DepletedZone

OverfishingZone

BufferZone

TargetZone

MSY

0.91 MSY

0.75 MSY

Comparison Schaefer vs Fox

0

0.2

0.4

0.6

0.8

1

0 0.5 1 1.5 2

B /B msy

Y/M

SY

B msy0.5 B msy 1.3 B msy 2 B msy

Fox Schaefer

Status of European Stocks

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.5 1 1.5 2

B /B msy

Y/M

SY

B msy0.5 B msy 1.3 B msy

Status of European Stocks

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 0.5 1 1.5 2

Biomass / B MSY

Lan

din

gs

/ M

SY

B MSY 1.3 B MSY

MSY

0.9 MSY

Move stocks here.Landings may then be 60% higher

Froese et al., accepted in FAF

Test Case North Sea Herring (I)

0

200

400

600

800

1,000

1,200

0 500 1,000 1,500 2,000 2,500 3,000 3,500

Spawner Biomass (1000 t)

Lan

din

gs

(100

0 t)

1960

1960

1962

19621967

1967

1977

1978

1978

1.3 B msy

Test Case North Sea Herring (II)

0

200

400

600

800

1,000

0 500 1,000 1,500 2,000 2,500 3,000 3,500 4,000

Spawner Biomass (1000 t)

Lan

din

gs

(100

0 t)

2008

2008

1985

1985 1987

1983

20032003

1979

1.3 B msy

1987

Test Case Blue Whiting

0

500

1,000

1,500

2,000

2,500

0 2,000 4,000 6,000 8,000 10,000 12,000

Spawner Biomass (1000 t)

Lan

din

gs

(100

0 t)

1.3 B msy

1981

2008

1999

Lowrecruitment

Highrecruitment

2006 Lowrecruitment

1981

20062008

1983

1999

Comparison F-based vs Y-based

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2

B / B msy

F /

Fm

sy o

r Y

/ M

SY

B msy

Proposed HCR

F -based HCR

How to Get to Bmsy with Least Pain?

Cod, Eastern Baltic

0

100

200

300

400

500

600

700

800

900

1000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

SS

B a

nd

Lan

din

gs

(100

0 t)

BMSY

MSY

Froese & Proelß Fish & Fisheries 2010

Thank You

Rainer Froese

IFM-GEOMAR

rfroes@ifm-geomar.de