CRIMAC - Annual Report 2020

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Effects of sound from seismic surveys on fish reproduction, the management case from Norway

Anthropogenic noise has been recognized as a source of concern since the beginning of the 1940s and is receiving increasingly more attention. While international focus has been on the effects of noise on marine mammals, Norway has managed seismic surveys based on the potential impact on fish stocks and fisheries since the late 1980s. Norway is, therefore, one of very few countries that took fish into account at this early stage. Until 1996, spawning grounds and spawning migration, as well as areas with drifting eggs and larvae were recommended as closed for seismic surveys. Later results showed that the effects of seismic surveys on early fish development stages were negligible at the population level, resulting in the opening of areas with drifting eggs and larvae for seismic surveys. Spawning grounds, as well as concentrated migration towards these, are still closed to seismic surveys, but the refinement of areas and periods have improved over the years. Since 2018, marine mammals have been included in the advice to management. The Norwegian case provides a clear example of evidence-based management. Here, we examine how scientific advancements informed the development of Norwegian management and how management questions were incorporated into new research projects in Norway.publishedVersio

Predicting the effects of anthropogenic noise on fish reproduction

Aquatic animals use and produce sound for critical life functions, including reproduction. Anthropogenic noise is recognized as a global source of environmental pollution and adequate conservation and management strategies are urgently needed. It becomes therefore critical to identify the reproductive traits that render a species vulnerable to acoustic disturbances, and the types of anthropogenic noise that are most likely to impact reproduction. Here, we provide predictions about noise impact on fish reproduction following a two-step approach: first, we grouped documented effects of noise into three mechanistic categories: stress, masking and hearing-loss, and test which type of noise (continuous vs intermittent and regular vs irregular) was most likely to produce a significant response in each category with either a meta-analysis or a quantitative review, depending on data availability. Second, we reviewed existing literature to predict which reproductive traits would render fish most sensitive to stress, masking and hearing-loss. In step one, we concluded that continuous sounds with irregular amplitude and/or frequency-content (e.g. heavy ship traffic) were most likely to cause stress, and continuous sounds were also most likely to induce masking and hearing-loss. From step two we concluded that the vulnerability of a species to noise-induced stress will mainly depend on: (1) its potential to reallocate reproduction to more quiet times or locations, and (2) its vulnerability to masking and hearing-loss mainly on the function of sound communication in its reproductive behaviour. We discuss in which stages of reproduction fish are most likely to be vulnerable to anthropogenic noise based on these findings.publishedVersio

Havforskningsinstituttets rådgivning for menneskeskapt støy i havet: seismikk, elektromagnetiske undersøkelser og undersjøiske sprengninger

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Behavioural effects of seismic dose escalation exposure on captive mackerel (Scomber scombrus)

Petroleum and fisheries are two of the most important industries in Norway, and the goal for management is sustainable coexistence for both. Mackerel is an important pelagic fishery resource, and mackerel can very well detect the seismic sound signals. The aim of this project was to investigate the behavioural responses of mackerel to seismic signals, and to evaluate potential responses in terms of affecting the fishery. Wild captured mackerel in a net pen was exposed to escalating seismic signals from an approaching source vessel, while behaviour was constantly monitored with video and echosounder, as well as the sound pressure level and particle motion level recorded with hydrophone and particle motion sensor, respectively. Fish behavior was analyzed in terms of swimming speed, vertical distribution, schooling and group dynamic. We aimed at conducting a dose escalation to identify the sound level at which a response is initiated. No clear responses were identified in response to the sound exposure. In addition, behavioural responses of farmed salmon and rainbow trout was monitored by video surveillance at three close-by aquaculture farms to avoid any potential harmful effects on the farmed fish. However, no behavioural responses in terms of swimming dynamic, swimming speed and collective behavior were observed from these videos .publishedVersio

SpawnSeis MV exposure experiment - Survey Report — IMR Survey number 2022812

In the project SpawnSeis MV, we aimed to study how a novel seismic source, a marine vibrator, affects behaviour and acoustic communication of wild, free ranging, spawning cod. Cod behaviour was studied by using acoustic telemetry to track movement of individual cod in Austevoll, Norway. During the cod spawning season in 2020 and 2021, a 5-day exposure survey with seismic airguns was used to examine cod movement in response to such sound exposure. In the spawning season of 2022, an exposure survey with a marine vibrator was conducted to evaluate differences between how cod respond to these two types of seismic testing (airguns and marine vibrator). The current cruise report describes the exposure survey with the marine vibrator.SpawnSeis MV exposure experiment - Survey Report — IMR Survey number 2022812publishedVersio

Spawning Atlantic cod (Gadus morhua L.) exposed to noise from seismic airguns do not abandon their spawning site

Seismic airgun surveys may disturb and displace fish at large ranges. If such displacement causes fish to abandon spawning grounds, reproductive success could be impacted. To investigate whether airgun sound causes cod (Gadus morhua L.) to leave their spawning grounds, acoustic telemetry arrays were deployed on two cod spawning grounds: a test and a reference site. From 2019 to 2021, 136 mature cod from the test site and 45 from the reference site were tagged with acoustic transmitters. Intermittent seismic shooting of two 40 in.3 airguns for 1 week during the spawning periods of 2020–2021 resulted in fluctuating sound exposure levels (SEL) at the test site, comparable to a full-scale industrial survey 5–>40 km away. Residency and survival of tagged cod were analysed with capture–mark–recapture models fitted to the detection and recapture data. Departure rate of the mature cod varied between spawning seasons but was similar between the test and reference sites. Neither survival nor departure significantly differed between seismic exposure and baseline periods. The results indicated that exposure to airguns at received SEL of up to ∼145 dB re 1 μPa2 s, comparable to a seismic survey occurring several kilometres away, did not displace tagged cod from spawning grounds.publishedVersio

Advice from the Institute of Marine Research on anthropogenic noise in the sea

Havforskningsinstituttet gir råd for alle operasjoner til havs som involverer bruk av lydkilder som kan påvirke marine økosystemer. Dette inkluderer vitenskapelige undersøkelser, utbygging og sprenging i sjø, seismiske og elektromagnetiske undersøkelser i forbindelse med petroleumsvirksomhet og utbygging og drift av vindkraftanlegg til havs. Denne rapporten er en sammenstilling av tilgjengelig kunnskap omkring hvordan de overnevnte typer av undersjøisk støy påvirker livet i havet. Videre evalueres denne kunnskapen i lys av hvilke konsekvenser dokumenterte effekter kan gi på økosystemet. Denne rapporten er inndelt med et kapittel for hver av de overnevnte støykildene (seismikk, elektromagnetiske undersøkelser, undersjøiske sprenginger og vindkraft til havs), som igjen er inndelt i delkapitler med 1) kunnskapsgrunnlag, 2) konsekvensvurdering og 3) råd. Rapporten inneholder konkrete råd fra Havforskningsinstituttet for 2022 for de ulike typene av støy.The Institute of Marine Research (IMR) is responsible to provide advice on the impact of anthropogenic sound sources on marine life. This include scientific instigations, underwater explosions, seismic and electromagnetic surveys related to petroleum activity and offshore wind installations. This report intends to summarize available literature on how the above-mentioned sound sources impact marine life. Further, this knowledge is evaluated to show the reader the reasoning behind the advices given. This report give one chapter for each of those sound sources (seismic, underwater explosions, electromagnetic investigations and offshore wind), again separated into subchapters of 1) review of scientific knowledge, 2) evaluation of knowledge and 3) advice. This report includes the advices from IMR for the topics seismic surveys, electromagnetic surveys, underwater explosions and offshore wind valid for 2022

Advice from the Institute of Marine Research on anthropogenic noise in the sea

Havforskningsinstituttet gir råd for alle operasjoner til havs som involverer bruk av lydkilder som kan påvirke marine økosystemer. Dette inkluderer vitenskapelige undersøkelser, utbygging og sprenging i sjø, seismiske og elektromagnetiske undersøkelser i forbindelse med petroleumsvirksomhet og utbygging og drift av vindkraftanlegg til havs. Denne rapporten er en sammenstilling av tilgjengelig kunnskap omkring hvordan de overnevnte typer av undersjøisk støy påvirker livet i havet. Videre evalueres denne kunnskapen i lys av hvilke konsekvenser dokumenterte effekter kan gi på økosystemet. Denne rapporten er inndelt med et kapittel for hver av de overnevnte støykildene (seismikk, elektromagnetiske undersøkelser, undersjøiske sprenginger og vindkraft til havs), som igjen er inndelt i delkapitler med 1) kunnskapsgrunnlag, 2) konsekvensvurdering og 3) råd. Rapporten inneholder konkrete råd fra Havforskningsinstituttet for 2022 for de ulike typene av støy.The Institute of Marine Research (IMR) is responsible to provide advice on the impact of anthropogenic sound sources on marine life. This include scientific instigations, underwater explosions, seismic and electromagnetic surveys related to petroleum activity and offshore wind installations. This report intends to summarize available literature on how the above-mentioned sound sources impact marine life. Further, this knowledge is evaluated to show the reader the reasoning behind the advices given. This report give one chapter for each of those sound sources (seismic, underwater explosions, electromagnetic investigations and offshore wind), again separated into subchapters of 1) review of scientific knowledge, 2) evaluation of knowledge and 3) advice. This report includes the advices from IMR for the topics seismic surveys, electromagnetic surveys, underwater explosions and offshore wind valid for 2022.publishedVersio

Behavioural responses of wild, spawning Atlantic cod (Gadus morhua L.) to seismic airgun exposure

Seismic airgun surveys to map petroleum deposits in the seabed may impact behaviour of marine animals over large distances. Understanding whether fish spawning behaviour is affected by this anthropogenic noise source is important because reproductive success may be impacted. The fine-scale behavioural responses of Atlantic cod to airgun exposure over an extended period were investigated using an acoustic telemetry positioning system on a spawning ground in Norway. During 2019 to 2021, 135 spawning cod were equipped with telemetry sensor tags and were exposed to airgun shooting during the spawning periods of 2020 and 2021, with varying received sound levels comparable to a full-scale survey at distances of 5 to >40 km. Cod demonstrated only weak responses to the disturbance from repeated 3-h treatment periods over 5-d, swimming on average slightly deeper during seismic exposure compared to silent control periods. This response varied between individuals. Longer-term effects of seismic exposure on swimming depth were not detected. No changes in swimming acceleration, displacement, or area use occurred. These results suggest that relatively distant seismic surveys do not substantially alter cod behaviour during the spawning period at received sound exposure levels varying between 115 and 145 dB re 1 µPa2s over a 5-d period.publishedVersio