Scientific surveys carried out by Ifremer
Characteristics of the surveys carried out by Ifremer
North Sea
Southern North Sea
Every years since 1980 France contributes one month of ship time to the IBTS (International Bottom Trawl Survey) in the first quarter using a GOV trawl. On average 58 hauls are carried out. The southern North Sea is sampled by four countries (France, Belgium, Danmark and Germany) who together carry out about 200 hauls per year. Each haul lasts half an hour corresponding to a swept area of about 0.067 km². IBTS provides a representative picture of the 678 000 km² of the area.
For more information on the IBTS survey
Eastern English Channel
Eastern English Channel
French survey CGFS (Channel Ground Fish Survey) lasting one month and internationally coordonnated together with the IBTS survey. The survey takes place every year since 1988. On average 90 half hour hauls are carried out with a small GOV trawl. Each haul covers about 0.03 km². This survey provides a representative picture of the 70 748 km² of the Eastern English Channel.
For more information on the CGFS survey
Somme river bay
The survey in the nursery area of the Somme rive bay (NourSomme) lasts one week in September-October each year since 1995, using a 2m-beam trawl in the estuary and a 3m-beam trawl in the more open areas. On average 50 hauls are carried out. Haul duration is 7 minutes covering 0.001 km² in the estuary part and 15 minutes covering 0.004 km² in the more open part. This survey provides a representative picture of the 720 km² of the Somme baie.
For more information on the NourSomme survey
Seine river bay
Yearly surveys carried on in the Seine estuary and the eastern bay of Seine (NourSeine), principally in autumn from 1995 to 2002. The main objective was to identify the coastal fish nurseries and to assess the fish and macro-benthos richness. About 45 hauls are done during each survey, using a standard beam trawl.
For more information on the NourSeine survey
Eastern English Channel
Cap de Flamanville area
Two surveys of 15 jours each using pots around cap de Flamanville (CrustaFlam), in June and September, since 1986: 1200 sets per survey in an area covering 26 km².
For more information on the CrustFlam survey
Northeast Atlantic
Celtic Sea
The Evhoe survey (Evaluation des ressources halieutiques de l'ouest européen) lasts one month in the fourth quarter every year since 1997. On average 75 half-hour hauls are carried out with a GOV trawl. Each haul covers about 0.067 km². This survey provides a representative picture of the 150 000 km² of the Celtic Sea.
For more information on the Evhoe surveys
Bay of Biscay
Evhoe survey
The Evhoe survey (Evaluation des ressources halieutiques de l'ouest européen) lasts one month in the fourth quarter every year since 1992 (except 1993 and 1996). On average 70 half-hour hauls are carried out with a GOV trawl. Each haul covers about 0.067 km². This survey provides a representative picture of the 72 500 km² of the Bay of Biscay.
For more information on the Evhoe surveys
Pelgas survey
The main objectif of the scientific fisheries surveys is to provide information on ressource changes, using a standard sampling protocol. They are always carried out in the same areas, at the same time of year and with the same sampling tools, to allow comparisons among years. They provide information on both commercial and non-commercial species and their changes. Fish and shelfish species are counted, weighted and measured. For certain species other biological information is collected. Thus each survey provided a quantitive picture of the species assemblage in a given area during a certain time period. Additional information such as temperature, salinity, macrofauna, marin mammals, birds, macro waste etc. are collected during certain surveys, but this information is not presented here.
For the last two decades Ifremer has organised scientific fisheries surveys in the North Sea, the English Channel, the Atlantic and in the Mediterrean Sea for sampling pelagic, demersal and benthic ressources. The main objective is to produce abundance indices for the principal commercial species. The surveys collect also data for non-commercial species. Hence they contribute to the knowledge necessary for the development of an ecosystem approach to fisheries, in particular in the context of the common fisheries policy (CFP) and more generally the European marine strategy framework directive.
Different sampling tools are used:
- Scientific echosounders to assess the spatial distribution and biomass of small pelagic fish schools in the Bay of Biscay and the Gulf of Lion. Fish echotraces are identified (species composition and size distribution) using a pelagic trawl,
- Variants of a GOV (grande ouverture verticale) trawl for observing demersal species on the continental shelfs and upper slopes in the North Sea, Eastern English channel, Celtic Sea, Bay of Biscay, Gulf of Lions and East Corsica,
- A beam trawl for coastal zones and estuaries during surveys targeting juvenile flatfish: Somme and Vilaine river bays,
- Pots for the assessment of large crustaceans, in particular lobster, around Cap de Flamanville.
Common protocols are used by all participants for surveys carried out under international coordination in the North Sea, Eastern English channel, Celtic Sea, Bay of Biscay and the Mediterranean Sea. The data collected by the different research vessels are therefore comparable.
Acoustic surveys follow a systematic sampling plan comprised of regularly spaced parallel transects perpendicular to the isobaths. This spatially homogeneous sampling plan allows to precisely characterise the spatial distribution of pelagic species. Pelagic trawling is performed in an adaptative way to identify fish echotraces.
Each bottom trawl survey area is subdivided in strata according to bottom depth, latitude or other criteria. The sampling protocol specifies the number of hauls or pots by stratum. For each bottom trawl survey the station location is determined following the specified sampling design. The aim is not to obtain the largest catches as fishers might attempt to do, but to collect comparable data for detecting time trends.
For more information on the Pelgas surveys
Vilaine river bay
Survey in the nursery area of the Vilaine river bay (NourVil) lasted one week every year in autumn from 1980 à 2010, except 1991, 1994, 1995, 1998, 1999, 2006 and 2007. It used a 3m-beam trawl. On average 30 15-min hauls were carried out covering each about 0.0041 km². This survey provides a representative picture of the 330 km² of the Vilaine bay.
For more information on the Nourvil survey
Mediterranean Sea
Gulf of Lions
French contribution to the internationally coordinated Medits (International bottom Trawl Surveys in the Mediterranean) survey, lasting one month in the second quarter every year since 1994 using a GOV bottom trawl with short wings. On average 69 hauls are carried out; haul duration is half an hour above 200 m depth which corresponds to 0.05 km² and one hour for bottom depths greater than 200 m (0.1 km²). Medits provides a representative picture of the 13 860 km² of the gulf of Lions.
For more information on the Medits surveys
- Manuel des protocoles Medits, Version 1 (1994)
- Manuel des protocoles Medits, Version 2 (1995)
- Manuel des protocoles Medits, Version 3 (1999)
- Manuel des protocoles Medits, Version 4 (2001)
- Manuel des protocoles Medits, Version 5 (2007)
- Manuel des protocoles Medits, Version 6 (2012)
East Corsica
French contribution to the internationally coordinated Medits (International bottom Trawl Surveys in the Mediterranean) survey, lasting one week in the second quarter every year since 1994 except 2002 using a GOV bottom trawl with short wings. On average 20 hauls are carried out; haul duration is half an hour above 200 m depth which corresponds to 0.05 km² and one hour for bottom depths greater than 200 m (0.1 km²). Medits provides a representative picture of the 4 562 km² of Eastern Corsican island plateau.
For more information on the Medits surveys
