BSEP116B Biodiversity in the Baltic Sea - Helcom

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6.8.2 Activities generating noise in the Baltic Sea Industrial activities Industrial noise frequently originates from few, more or less stationary sound sources during resource exploration, extraction, construction and operation of wind turbines as well as use of deterrent devices in fisheries such as pingers. During pile-driving operations associated with construction, e.g. of wind farms, noise is produced at high intensity levels at broad-band frequencies. Pile-driving is estimated to be audible for harbour porpoises and harbour seals at least 80 km from the source (Thomsen et al. 2006) Within this zone the noise can potentially interfere with communication and echolocation clicks. The zone where behavioral changes can be expected range from a few up to 20 km, and hearing loss may occur within a few hundred meters up to a few kilometers from the pile-driving. Hearing capability differs considerably between fish species (Figure 6.8.1). For cod and herring that have relatively good hearing the audible zone is estimated at up to 80 km and behavioral changes are considered possible close to the pile-driving activity (Thomsen et al. 2006). Underwater explosion Operational noise of wind turbines is of lower intensity than pile-driving and the impact on both mammals and fish is likely to be restricted (Madsen 2006). However, noise simulations show that even operating turbines may have a potentially masking effect at least at short ranges in the open sea (Lucke et al. 2007). Direct studies on the response of mammals to operating wind farms are currently taking place in the Danish wind farm “Nysted” (Diederichs et al. 2008, Teilmann et al. 2008). High pressure airguns are commonly used in seismic surveys to produce sound pulses of low frequency and high intensity. There are several observations of behavioral change of mammals associated to airgun operation, in particular involving avoidance of the area surveyed (Gordon et al. 2003) as well as ceased communication and physical effects on cetaceans (Nowacek et al. 2007). In the immediate vicinity of airgun operation fish kills have been observed. Reduced catches of fish, e.g. cod, have also been noted in areas of seismic surveys, lasting up to several days after the activity has ceased (Engås et al. 1996). Industrial seismic surveys use large arrays with multiple airguns to locate geological structures associated with oil and gas. Airguns are also used in geological mapping in the Baltic Sea area, usually involving fewer airguns with lower impact than those used for exploration surveys. However, all air guns can be heard over very long distances under water. High-frequency SONARs (>10 kHz) that are commonly used to map the seafloor or to locate fish are within the hearing frequency of many marine mammals, but they have a limited transmission range in water. Masking effects cannot be disregarded although concrete evidence is still lacking. Recent research (M. Lahtinen, pers. comm.) indicates that depth and fishing echo-sounders using 50 kHz frequency can be problematic for toothed whales and possibly seals, as this frequency is in their important hearing range. Even small boats and fishing vessels have these echo-sounders on almost continually whenever map plotters are being used. 126 Ship traffic Shipping constitutes a rather diffuse and omnipresent sound source that is difficult to quantify and evaluate. However, large cargo vessels
are considered to be significant contributors to anthropogenic noise in the marine environment. In the period 1950–2000 it is estimated that noise from shipping increased the sound level in the world’s oceans by 16 dB, i.e. it has doubled several times. The noise emitted from ships varies considerably between vessels, but basically the larger the ship and the older the ship, the louder they are. The intense sound levels are mainly of low frequency (
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Baltic Sea Environment Proceedings
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Published by: Helsinki Commission K
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TABLE OF CONTENTS PREFACE . . . . .
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6.6 Hazardous substances . . . . .
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1 INTRODUCTION 8 1.1 An integrated
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Box 1.1. Biodiversity The term biod
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of saline water from the North Sea
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14 On a global scale, marine ecosys
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Box 1.2. Regime shifts in the Balti
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2 MARINE LANDSCAPES AND HABITATS 18
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From an ecological point of view, a
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Box 2.1.2. The Baltic marine landsc
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• A coherent data set on benthic
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Denmark Estonia Finland Germany Lat
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Mud-sandflat, Greifswald Lagoon, Ge
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3 COMMUNITIES Communities are assem
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32 Spring bloom index 1200 1000 800
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34 Unusual events and new species i
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36 Depth limit (m) the Gulf of Both
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Number of species 16 14 12 10 8 6 4
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Figure 3.2.7. Left panel shows pred
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Implications for the Baltic Sea Act
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Biomass (wet weight, mg per m 2 ) B
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the other hand, is not selected by
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iomass can be used to assess enviro
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Average number of species 20 15 10
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52 Macoma baltica where the influen
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the total BT identified for each ma
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Recruitment (thousands) 8000000 700
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Alien species Several alien fish sp
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4 SPECIES The number of species in
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Table 4.1.1. Results of dedicated a
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Number of stranded porpoises 180 16
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is recommended to survey harbour po
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Number of individuals 12000 10000 8
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Mean blubber thickness (mm) 40 35 3
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Breeding pairs 60000 50000 40000 30
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predation on nests and nesting adul
Page 78 and 79: sites outside the Baltic, decreased
Page 80 and 81: Table 4.3.1. Development of the pop
Page 82 and 83: 80 Number of breeding pairs 3000 25
Page 84 and 85: The strategic goal of the BSAP to h
Page 86 and 87: for a given site or area. The secon
Page 88 and 89: Mussel bed reef community, Jasmund,
Page 90 and 91: Table 5.3. Assessment results of th
Page 92 and 93: Aerial photo of harbours seals (Pho
Page 94 and 95: 6 HUMAN PRESSURES ON BIODIVERSITY A
Page 96 and 97: Table 6.1.1. Catch range during the
Page 98 and 99: Baltic herring trawling, Bothnian B
Page 100 and 101: 6.1.3 Major international framework
Page 102 and 103: 100 Oil turnover (millions of tonne
Page 104 and 105: NOx emissions and sewage Macrophyte
Page 106 and 107: Communication links There are a num
Page 108 and 109: Figure 6.3.3. Left: concrete-stone
Page 110 and 111: ecommendations would contribute to
Page 112 and 113: Tourist fishing 110 cial fishery fo
Page 114 and 115: 112 Figure 6.5.1. Integrated classi
Page 116 and 117: can be considered as having been a
Page 118 and 119: Although no direct, dramatic mass m
Page 120 and 121: Bearing in mind the complex hydrogr
Page 122 and 123: Box 6.7.1. Invasion status of the B
Page 124 and 125: Table 6.7.1. Examples of ecological
Page 126 and 127: munities that formerly consisted of
Page 130 and 131: 128 and fish in the Baltic Sea area
Page 132 and 133: 800 700 600 bag of the two German B
Page 134 and 135: Fish swarm on kelp (Laminaria sp.)
Page 136 and 137: tion of ice cover, either through r
Page 138 and 139: 7 STATUS OF THE NETWORK OF MARINE A
Page 140 and 141: Box 7.1. Natura 2000 network of pro
Page 142 and 143: 25 20 on how the criteria on ecolog
Page 144 and 145: estrial, nearshore marine, and offs
Page 146 and 147: 144 >30 psu 18-30 psu 11-18 psu 7.5
Page 148 and 149: Permission needed Restricted Forbid
Page 150 and 151: Figure 7.8.a. MARXAN ’best portfo
Page 152 and 153: The BSPA network is relatively well
Page 154 and 155: Mammals. Among the mammals, the pop
Page 156 and 157: 154 taxonomic groups and communitie
Page 158 and 159: 156 provided by an ecosystem. Use o
Page 160 and 161: 158 Reduction of human pressures Wh
Page 162 and 163: 160 fishing on fish population dyna
Page 164 and 165: 162 Baden, S., Boström, C. (2001).
Page 166 and 167: 164 Season 2001-2002. Acta Zoologic
Page 168 and 169: 166 Gasiūnaitė, Z.R., Cardoso, A.
Page 170 and 171: 168 HELCOM & OSPAR (2003): Joint HE
Page 172 and 173: 170 ICES (2008c). Report of the Bal
Page 174 and 175: 172 area: density-dependent effects
Page 176 and 177: 174 Noer, H., Clausager, I., Asferg
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176 Scheffer M., Carpenter S.R., Fo
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178 by passive acoustic monitoring.
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180 Warzaw, Poland Vilhunen, Jarmo,
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182 6.7 Alien speices Authors: Lepp
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ANNEX III: CONSERVATION STATUS OF T
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ANNEX IV: HABITAT OR SPECIES DISTRI
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ANNEX V: STATUS OF BREEDING AND WIN
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BSEP116B Biodiversity in the Baltic Sea - Helcom

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