Hopes and expectations: theconceptual course of future for marine ecosystems and fishery

Latvian Institute of Aquatic EcologyLatvian Fish Resources Agency

UL Institute of BiologyUL Faculty of Biology

Expected outcomes of WP work

• Improved knowledge on possible processes;• Participation in constructing environmental

legislation;• Recommendations for management and

adaptation strategies.

Gulf of Riga – future scene

Gulf of Riga – ecosystem projections

Winters without ice cover - • Earlier development of plankton communities,

higher biomassShift from Achnantes taeniata to Thalassiosira

baltica, Chaetoceros spp., Melosira nummuloides

• Shift in breeding time of benthic species, mostly amphipods

Gulf of Riga – ecosystem projectionsSprings with faster

stratification –• Dominance of

dinoflagellates or ...nothing special;

• Higher share of small size fraction in zooplankton.

0

4000

8000

12000

mg/

m3

0

10

20

30

40

119. st.

0

4000

8000

12000

mg/

m3

0

10

20

30

40165. st.

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1.24

.02.

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5.

C yanophyceae

D iatom ophyceae

D inophyceae

Cryptophyceae

Chlorophyceae

Pârçjâs

H lorofils a

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.8.

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12.

27.1

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18.1

2.19

.12.

Gulf of Riga – ecosystem projectionsWarmer summers: two options

Increased wind intensity:• Frequent upwellings,

productive coastal areas;• Reduced cyanobacterial

blooms.

Calm weather dominating:

Gulf of Riga – ecosystem projections

• Zooplankton Acartia bifilosa, Limnocalanus macrurus,

Evadne nordmanni, Pleopsis polyphemoides Daphnia spp., Cyclops spp.

• Macrozoobenthos Gammarus sp., Bathyporeia pilosa, Marenzelleria viridis, Macoma baltica

• Phytobenthos ???

Gulf of Riga - fisheries• Gulf of Riga

herring – growth expected and forecasted, still – spawning stock biomass hardly above the mean;

• Reason – high fishing mortality, low recruitment.

0

20000

40000

60000

80000

100000

120000

140000

1977

1980

1983

1986

1989

1992

1995

1998

2001

2004

2007

Nār

sta

bar

a b

iom

asa,

t

0

1000

2000

3000

4000

5000

6000

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9000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

paaudze

milj

on

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2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

The Baltic Sea – ecosystem projections in conditions of reduced salinity and higher

temperature• Species structures

gradually similar to the Gulf of Riga;

• Coastal areas – level of human activities significant: nutrient loads;

• Further reduction of inhabited bottoms.

The Baltic Sea - fisheries

• The Eastern Baltic cod – fishing mortality as a key factor

1980 2000 2020 2040 2060 2080 2100

020

040

060

0

F = 1.08

Year

SS

B (

thou

sand

tons

)

w ithout climate changew ith climate change

1980 2000 2020 2040 2060 2080 21000

200

500

F = 0.7

Year

SS

B (

thou

sand

tons

)

1980 2000 2020 2040 2060 2080 2100

040

010

00

F = 0.3

Year

SS

B (

thou

sand

tons

)

1980 2000 2020 2040 2060 2080 2100

010

0020

00

F = 0

Year

SS

B (

thou

sand

tons

)

Conclusions

• Coastal zone would strengthen its position as a key area in the aspect of productivity and biodiversity;

• The Gulf of Riga and the Baltic Sea would continue being attractive for invasive species;

• The climate change would intensify or mask the impact of key factor - human activities.

Recommendations:• elaborate and implement the load reduction activities as soon as

possible in all related areas (agriculture, water resources management etc.);

• create zonation of the coastal underwater areas with various level of protection according to the functional importance of the site;

• perform regular observations of marine environment and provide model calculations of processes, based on the observations for flexible management decisions;

• reduce the fishing mortality via exclusion of illegal fishing;

• follow the international regulations preventing the distribution of non-native species.

Thank you for your attention!