ICES Advice 2005, Volume 8 - Baltic Sea

1 THE BALTIC SEA

1.1 Ecosystem overview 1

1.1.1 Ecosystem components 1

1.1.2 The major environmental influences on ecosystem dynamics 3

1.1.3 The major effects of the ecosystem on fisheries 4

1.1.4 The major effects of fishing on the ecosystem 5

1.1.5 Other effects of fishing on seabirds and mammals 6

1.1.6 Conclusions 6

1.1.7 References 6

1.2 The human use of the ecosystem 11

1.2.1 Overall impacts 11

1.2.2 Fisheries 11

1.3 Assessments and advice 13

1.3.1 ICES advice for fisheries management 17

1.3.2 Special requests 28

1.3.2.1 Long-term management of Baltic cod (DG FISH) 28

1.3.2.2 DNA analysis of Baltic salmon (DG FISH) 32

1.3.2.3 Quality assurance of biological and chemical measurements in the Baltic Sea (HELCOM) 35

1.3.2.4 Marine habitat classification and mapping system for the Baltic Sea (HELCOM) 36

1.3.2.5 Seal and harbour porpoise populations in the Baltic marine area (HELCOM) 38

1.3.2.6 To review and revise the quality assurance section of the PLC Guidelines (HELCOM) 43

1.3.2.7 Closed areas within the Gotland Basin and Gdansk Deep in 2005 45

1.3.2.8 Progress with revising estimates of smolt production potential in wild salmon rivers (IBSFC) 48

1.3.2.9 Fishing practices for salmon in the Gulf of Finland (IBSFC) 50

1.4 Stock summaries The Baltic Sea

1.4.1 Cod in Subdivisions 22 24 51

1.4.2 Cod in Subdivisions 25 32 59

1.4.3 Herring in Subdivisions 22 24 and Division IIIa (spring spawners) 68

1.4.4 Herring in Subdivisions 25 29 (excluding Gulf of Riga herring) and 32 77

1.4.5 Herring in the Gulf of Riga 85

1.4.6 Herring in Subdivision 30, Bothnian Sea 92

1.4.7 Herring in Subdivision 31, Bothnian Bay 100

1.4.8 Sprat in Subdivisions 22 32 105

1.4.9 Flounder in Subdivisions 22-32 114

1.4.10 Plaice in Subdivisions 22-32 119

1.4.11 Dab in Subdivisions 22-32 122

1.4.12 Turbot in Subdivisions 22 to 32 124

1.4.13 Brill in Subdivisions 22 to 32 127

1.4.14 Salmon in the Main Basin and the Gulf of Bothnia (Subdivisions 22 31) 129

1.4.15 Salmon in the Gulf of Finland (Subdivision 32) 144

1.4.16 Sea trout 151