KB-WOT Quality assurance acoustics: overview and protocols 2008 version

The quality of IMARES' acoustic surveys proved quite unstable in recent years despite extra effort in this field to bring this instability down. The amount of involved scientists in acoustics has been small compared to demersal survey work. Therefore scientific standards of acoustic surveys are relatively low compared resulting in poor standardisation and minimal transparency. Highly specialised technical work made it even more difficult to exchange scientists within IMARES and the quality of acoustic surveys proved to be very sensitive to loss or change in personnel. This situation improved drastically in 2008 when more scientists got involved in acoustic projects and more effort was put in standardisation

Base line studies North Sea wind farms: strategy of approach for pelagic fish

The Dutch Government has decided to allow the construction of a Near Shore Wind Farm (NSW) demonstration project under the condition that a monitoring programme on - among other things - the ecological impacts is carried out. The Dutch government is responsible for providing a thorough description of the ecological reference situation in order to evaluate future effects of planned wind farms. This report describes the detailed plan of approach to establish the occurrence, density, population structure and migration patterns of pelagic fish fauna in the Dutch coastal zone. Sampling sites have been selected such that they cover the planned location of the Near Shore Wind Farm, cover reference sites and provide representative data of the pelagic fish community in the Dutch coastal zone

OWEZ pelagic fish, progress report and progression after T1

This report presents the current status of pelagic fish research in the Offshore Windfarm Egmond aan Zee (OWEZ) after having finalized the T0 baseline survey in 2003 and the T1 survey after construction of the wind farm in 2007. The T0 study indicated a highly dynamic pelagic fish community along the Dutch coast: species composition were found highly variable on a local scale and clear hot spots appeared abandoned when returning the next day. This picture was confirmed in the T1 survey where the species composition of the catches in the entire coastal zone were found completely different from the ones 4 years earlier. Although no clear and direct effect of the wind farm has been observed yet, the above described information tells us to look for more local effects where we should focus on underlying processes in fish community behaviour. The effects of a single windfarm seem difficult to measure but when the Dutch government allows a drastic increase in such wind farms in the North Sea, the local effect will become a regional effect and might start to influence complete fish stocks. Therefore, complementary research will be executed by studying fish behaviour in the wind farm itself

Cruise report hydro acoustic survey for blue whiting (Micromesistius poutassou) with R.V. Tridens, 05 - 23 March 2007

This is the report of the Dutch part of the international North East Atlantic hydro acoustic survey for blue whiting. The survey is coordinated by ICES and has been executed annually. Ireland, Russia, Iceland, Denmark, Faroes and Norway also participate in the survey. The purpose of the survey is to estimate the blue whiting stock of the North East Atlantic. The ICES uses this estimation is as a “tuning index” to assess the North East Atlantic blue whiting stock

Cruise report Hydro acoustic survey for blue whiting (Micromesistius poutassou) 7 march - 25 march 2005

Verslag van de Nederlandse deelname aan de Noord Atlantische akoestische survey voor blauwe wijting. Deze, door ICES gecoördineerde survey wordt jaarlijks uitgevoerd. Naast Nederland nemen Ierland, Denemarken, Faeröer, Rusland, IJsland en Noorwegen deel aan de survey. Het doel van de survey is het maken van een schatting van de grootte van de Noord Atlantische blauwe wijting populatie. Deze schatting wordt gebruikt als een “tuning index” door ICES om de omvang van de populatie vast te stelle

North Sea hydro acoustic herring survey. Survey report for R/V "TRIDENS" 26 June - 21 July 2006

Dit is het verslag van de Nederlandse deelname aan de Noordzee akoestische survey voor haring. Deze, door ICES gecoördineerde survey wordt sinds 1991 jaarlijks uitgevoerd. Naast Nederland nemen Schotland, Duitsland, Denemarken en Noorwegen deel aan de survey. Het doel van de survey is het maken van een schatting van de grootte van de Noordzee haring populatie. De toegepaste methode is echo-integratie. Door transecten te varen in het gebied wordt het totale akoestische oppervlak per oppervlakteeenheid bepaald. Door het uitvoeren van vistrekken wordt de soort-samenstelling bepaald. Van haring en sprot worden daarnaast biologische monsters genomen om leeftijd en rijpheid te bepalen. Voor deze soorten kan aldus een schatting van de populatie, uitgesplitst naar leeftijd en rijpheid, gemaakt worden. De biomassa van de totale haring-populatie in het door het Nederlandse schip bemonsterde gebied wordt geschat op 404 duizend ton, die van sprot op 31 duizend ton. De paai-biomassa van haring wordt geschat op 131 duizend to

Cruise report hydro acoustic survey for blue whiting (Micromesistius poutassou) with R.V. Tridens, 17 March - 04 April 2008

This is the report of the Dutch part of the international North East Atlantic hydro acoustic survey for blue whiting. The survey is coordinated by ICES and has been executed annually. The purpose of the survey is to estimate the blue whiting stock of the North East Atlantic. The ICES uses this estimation is as a “tuning index” to assess the North East Atlantic blue whiting stock. The applied method was echo integration. By sailing transects over the survey area, the total acoustic cross-section can be calculated by surface area sampled. Trawling identified species composition of localized schools. The length composition of each species was determined. Blue whiting was examined on age and fecundity from which a split up stock structure was mad

North Sea hydro acoustic herring survey. Surevy report for FRV 'TRIDENS' 23 June - 18 July 2003

This is the report of the Dutch part of the international North Sea hydro acoustic survey for herring. The purpose of the survey is to estimate the herring stock of the North Sea. For this survey a Simrad 38 kHz splitbeam transducer was used together with a Simrad EK60 echo sounder. The applied method was echo integratio

Towards abundance estimates for jack mackerel in the South Pacific based on acoustic data collected by the commercial vessels

Pelagic trawlers make intensive use of echosounders and therefore could potentially be used as acoustic data collection platforms. This project investigated the possibility of collecting acoustic data and its potential utility to estimate fish stock biomass. The scope of the project was to develop and - when possible - test the tools that would be necessary for large scale data collection from commercial vessels, and investigate the suitability of acoustic data to derive abundance indices

Combined Fish and Birds survey in the Dutch coastal zone

Knowledge on the relationship between birds and fish is important when assessing the impact of infrastructural development on birds and fish in the coastal zone. It can have a direct effect on bird migration routes and resting areas. It can also have an indirect effect by changing the fish community and hence food availability for the bird community. RIKZ assigned Bureau Waardenburg a continuation of the prematurely terminated Flyland project in which the relationship between fish and birds should have been studied. This renewed project aims at describing the ecological relationships between marine birds and their food sources, mainly pelagic fish. The present report describes the results of a study on the relationship between fish and birds in the Dutch coastal zone. With this knowledge, impact of future infrastructural development on birds and their food (fish) can be better assessed