Spatial distribution of fish stocks in a climate perspective Nordic Climate Fish Conference 2011,...

Spatial distribution of fish stocks in a climate perspective

Nordic Climate Fish Conference 2011, Solstrand

Geir Odd Johansen

Overview

• FishExChange objectives• The FishExChange database• Data examples• Looking for important factors influencing the

variation in geographical distribution• Ambient temperature• The complex interplay• Conclusions

FEC principal objective

• Evaluate the effect of climate change in the Barents Sea and adjacent areas on distribution of fish stocks, in perspective of national marine areas

• Further, evaluate what effect this will have on division of national fish quotas and economical consequences for the fisheries

Spatial approach

FEC objectives

FEC Task 2

• The fish stocks– Based on deliverables from Task 1

(oceanography)– Age specific spatial fields (maps) of historical fish

distributions• Mechanisms behind spatial distribution

– Links to climate indicators– Interactions between species– Cover most of the life history

– Spatial fields (maps) of most likely future fish distribution

FEC objectives

ChallengeData heterogeneity in space and time

The FEC database

Allowing data to meet in a common

framework andmaking them talk

together!

Climate data

Model output

Fish survey data

Fisheries data

Horizontal, vertical, and temporal structure on different scales

Data from fish surveys in the FEC database

The FEC database

Data from fish surveys in the FEC database

• Commercial species• Based on different sources of raw data• Synoptic surveys for abundance estimation• Trawl catches corrected for swept area• Comprehensive metadata• Protocols for planning, preparation of data

and input• Data catalogues with temporal coverage

The FEC database

Data from fish surveys in the FEC database

• 0-group autumn, pelagic trawl– Blue whiting, capelin, cod, Greenland halibut,

haddock, herring, mackerel, redfish, saithe and polar cod

• Cod, bottom trawl– Winter survey, 5 cm size groups, age 1-13+– Summer/autumn/ecosystem surveys 5 cm size gr.

• Haddock, bottom trawl– Winter survey, 5 cm size groups, age soon– Summer/autumn/ecosystem surveys 5 cm size gr.

The FEC database

Data from fish surveys in the FEC database

• Capelin, acoustic surveys autumn– Age 1-5

• Polar cod , acoustic surveys autumn– Age 1-5

• Saithe, acoustic survey autumn planned– Winter survey, 5 cm size groups, age soon– Summer/autumn/ecosystem surveys 5 cm size gr.

• + T, salinity and catch data

The FEC database

Other interesting species

• Blue whiting (Micromesistius poutassou Risso, 1827)

• Entering the BS from south-west

• High abundance in 2001-2007

• Interact with other species

The FEC database

Distribution area Spawning area

Other interesting species

• Atlantic mackerel (Scomber scombrus L.)– Observed at least as north as 74°N– Recently caught off the Murman coast

• Several fish species related to benthic habitats (e.g. eelpouts (Zoarcidae) and sculpins (Cottidae)– Habitat specific– Sensitive to temperature variation

The FEC database

What about the data?

Data example

• Example: Winter bottom trawl survey in the Barents Sea

• 1981-2009• Cod ≥ 45 cm (~ catchable size)• Density (No. Fish / nmi2)

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1981

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1982

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1983

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1984

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1985

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1986

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1987

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1988

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1989

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1990

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1991

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1992

Expansion of survey area from 1993 and onwards!

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1993

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1994

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1995

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1996

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1997 Limited survey coverage

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1998 Limited survey coverage

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1999 Limited survey coverage

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2000

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2001

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2002

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2003

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2004

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2005

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2006

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2007

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2008

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

2009

Distribution of NEA cod

Variation in geographical distribution

50° E30° E

50° E30° E10° E

75°

N70

° N

75°

N70

° N

1994

1980 1985 1990 1995 2000 2005 2010

71.5

72.0

72.5

73.0

Year

Ce

ntr

e o

f gra

vity

, co

d >

45

cm

, °N

74

75

76

77

78

Ice

co

ver

- so

uth

ern

lim

it, °

N

Distribution of NEA cod

In the Barents Sea, cod appeared in large quantities on Bear Island Bank in response to the warming of the early 20th century, resulting in the reestablishment of a cod fishery there after an absence of almost 40 years (Blacker, 1957). Cod also penetrated farther east to Novaya Zemlya and north of West Svalbard, during the 1920s (Beverton and Lee, 1965). Similar effects at west Greenland and Iceland.

Drinkwater 2005

Variation in geographical distribution

Spawning sites of NEA cod

Variation in geographical distribution

Cold periods:- Southwards displacement- Decreasing spawning biomass

Hot periods - Northwards displacement- Increasing spawning biomass

Sundby and Nakken (2008) IJMS

NEA cod the first year of life

Variation in geographical distribution

1980 1985 1990 1995 2000 2005 2010

1100

000

1400

000

Survey area

spatdat$Year

spat

dat$

AO

S

1980 1985 1990 1995 2000 2005 2010

4e+

058e

+05

Area of occupancy

spatdat$Year

spat

dat$

AO

O

1980 1985 1990 1995 2000 2005 2010

2530

3540

Easterly centre of gravity

spatdat$Year

spat

dat$

Cen

terX

1980 1985 1990 1995 2000 2005 2010

3032

3436

Northerly centre of gravity

spatdat$Year

spat

dat$

Cen

terY

NEA cod 1 yr old, winter

Variation in geographical distribution

1980 1985 1990 1995 2000 2005 2010

4e+

056e

+05

8e+

05Survey area

spatdat$Year

spat

dat$

AO

S

1980 1985 1990 1995 2000 2005 2010

2e+

056e

+05

Area of occupancy

spatdat$Year

spat

dat$

AO

O

1980 1985 1990 1995 2000 2005 2010

3236

4044

Easterly centre of gravity

spatdat$Year

spat

dat$

Cen

terX

1980 1985 1990 1995 2000 2005 2010

2428

32

Northerly centre of gravity

spatdat$Year

spat

dat$

Cen

terY

NEA cod 4 yr old, winter

Variation in geographical distribution

1980 1985 1990 1995 2000 2005 2010

4e+

056e

+05

8e+

05Survey area

spatdat$Year

spat

dat$

AO

S

1980 1985 1990 1995 2000 2005 2010

3e+

055e

+05

7e+

05

Area of occupancy

spatdat$Year

spat

dat$

AO

O

1980 1985 1990 1995 2000 2005 2010

3032

3436

38

Easterly centre of gravity

spatdat$Year

spat

dat$

Cen

terX

1980 1985 1990 1995 2000 2005 2010

2628

3032

Northerly centre of gravity

spatdat$Year

spat

dat$

Cen

terY

NEA cod 8 yr old, winter

Variation in geographical distribution

1980 1985 1990 1995 2000 2005 2010

4e+

056e

+05

8e+

05

Survey area

spatdat$Year

spat

dat$

AO

S

1980 1985 1990 1995 2000 2005 2010

1e+

053e

+05

Area of occupancy

spatdat$Year

spat

dat$

AO

O

1980 1985 1990 1995 2000 2005 2010

2630

34

Easterly centre of gravity

spatdat$Year

spat

dat$

Cen

terX

1980 1985 1990 1995 2000 2005 2010

2527

29

Northerly centre of gravity

spatdat$Year

spat

dat$

Cen

terY

Stock abundance

Variation in geographical distribution

Ambient temperature

Ambient temperature

Based on bottom temperatures in winter

1 yr old, winter

4 yr old, winter

8 yr old, winter

1980 1985 1990 1995 2000 2005

12

34

5

Ambient temperature for cod

ambient_temp$year

ambi

ent_

tem

p$co

dT1

Factors influencing geographical distribution

The complex interplay

Planque et al. 2010

spatial distribution

geographical attachment

environmental conditions

density dependent

habitat selection

spatial dependency

demographic structure

Persistence

species interactions

Conclusions

Conclusions

• Cod does not show signs of moving out of Norwegian exclusive economic zone - - - yet

• The period 1980-2010 is short in a global climate perspective• Study effects of climate variation

• Abundance is important for area of occupancy of a fish stock

• Important fish stocks for at least 1000 years• “Always” present even if climate varies?

Future challenges

“Prediction is very difficult, especially of the future” Niels Bohr, Danish physicist (1885 - 1962)

Temperature in the Kola hydrographic section

2,5

3,0

3,5

4,0

4,5

5,0

5,5

6,0

1900 1920 1940 1960 1980 2000 2020 2040 2060 2080

Temperatur

År ?

Year-to-year variation Long-time trend Long-term prognosis

”unknown situation”

”known situation”