Abstract
Abstract During three cruises in the Mid Atlantic Ridge area in 2016 and 2017, we studied the biomass of mesopelagic fish and its potential as a source of protein and oil for animal feed and human consumption. We collected samples of mesopelagic species down to a depth of 600 m, studied fish behaviour, identified and quantified the species composition of the catches, analysed the chemical composition of the catch samples, and evaluated the presence of unwanted substances. Results showed that Maurolicus muelleri (Mueller’s pearlside) and Benthosema glaciale (Glacier lantern fish) were the most abundant fish species in our samples and catches containing 80% fish can be a good source of protein and marine lipids including eicosapentaenoic acid (C20:5n3) and docosahexaenoic acid (C22:6n3). Unwanted substances, except for Cd and As, were present at levels far lower than the limits set by European Union regulations. However, our experiments identified challenges that may limit the efficiency of commercial operations in the Northeast Atlantic. Combined real-time optical and/or multifrequency acoustic systems will be needed to improve species identification and ensure cost-effective fishing operations. Also, selective trawls that target only fish and release unwanted species are needed to secure high-quality oils and proteins.
Highlights
The mesopelagic layer of the ocean at depths between 200 and 1000 m is inhabited by a large variety of species (Dalpadado et al, 1998), and mesopelagic species have been viewed as a potential harvestable resource since the 1970s (Gjøsæter and Kawaguchi, 2002; FAO 1997; 2014)
The upper most sound scattering layers (SSLs) mostly consisted of M. muelleri, krill, and different types of small jellyfish, as well as siphonophores (Figure 3 and Supplementary Video S1)
We found that 98% of individuals
Summary
The mesopelagic layer of the ocean at depths between 200 and 1000 m is inhabited by a large variety of species (Dalpadado et al, 1998), and mesopelagic species have been viewed as a potential harvestable resource since the 1970s (Gjøsæter and Kawaguchi, 2002; FAO 1997; 2014). Some of these species have been considered suitable for human consumption, but mostly they are aimed at supplying raw material to the fish meal and oil industry (Olsen et al, 2010). If exploited at sustainable levels without impacting the biodiversity and/or compromising the oceans’ role in climate regulation, the biomass of mesopelagic species may be a potential source of polyunsaturated FAs (PUFAs) and high nutritional value proteins to meet aquaculture demands and provide human nutrition (FAO, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
