Norway lobster. (Photo: IEO)
SPAIN
Tuesday, August 26, 2014, 22:00 (GMT + 9)
Scientists and technicians of the Spanish Institute of Oceanography (IEO) started Isunepca_0814 oceanographic research, whose main objective is the development of a direct assessment method to estimate the abundance of the Norway lobster (Nephrops norvegicus) in the Gulf of Cadiz using underwater images.
This study, which began on 22 August and will end on 2 September, is developed by experts from the IEO centres of Cadiz and Malaga, and students of the University of Cadiz and the Complutense University of Madrid, who travel on the oceanographic vessel Angeles Alvariño.
During the survey transects will be performed, that is to say, trips with pre-set distance and direction with a photogrammetric sled equipped with a video camera to obtain images of Norway lobster den that allows its counting and CTD, which will measure the water physical variables (temperature and salinity) in the study area.
In addition, sediment samples will be carried out with a dredge to learn about the grain size and organic matter content of the sediment in which the Norway lobster lives, the IEO reported.
Experts seek to identify species that are bigger than 500 microns accompanying the Norway lobster and establish a new methodology for evaluating the resource populations more effectively.
The Norway lobster is a sedentary species that spends most of its life inside dens. The time of day, season, environmental conditions, gender, animal size and reproductive status are some of the factors that determine whether they are hidden or not.
"Therefore, abundance indices based on conventional trawling assessment surveys do not need to be indicative of stock abundance," and becomes necessary to "implement new methodologies," the IEO explains.
Isunepca_0814 is part of the project entitled 'Estimating the abundance of the Norway lobster in the Gulf of Cadiz through underwater images' funded by the Biodiversity Foundation and the European Fisheries Fund (EFF).
During this survey the equipment and standardized methodology is being prepared and proposed in the working groups of the International Council for the Exploration of the Sea (ICES) aimed at estimating the Norway lobster abundance with such surveys.
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By Analia Murias