Land based on-growing of Atlantic cod (Gadus morhua) using Recirculating Aquaculture Systems; a case study from the Basque region (Northern Spain)

Abstract

Atlantic cod (Gadus morhua) is one of the most famous cold-water marine fish species. While the supply of Atlantic cod to European markets is relatively stable, this species continues to represent an interesting, and potentially lucrative, opportunity for commercial-scale aquaculture. Due to fishing restrictions and quota decreases over the last decade, the supply of Spanish-caught cod in European markets has declined, while the local demand for this species has increased. As wild-capture will not grow to meet this increased demand, land-based aquaculture of cod could represent a viable production model to satisfy demand. However, both capital investments and operation costs for a Recirculating Aquaculture System (RAS) farm are expected to be high, and therefore, all economic aspects must be taken into account before embarking on design or planning considerations. The influence of thermal control on growth, mortality and product quality also represent an important landmark when considering land-based aquaculture operations. The following represents a feasibility study to analyze the different economic scenarios and biological factors that can influence the business potential of growing this species in RAS. 2500 cod individuals were reared at two different thermal regimes (i.e., controlled and natural range, respectively) through 2 pilot RAS set up in the Basque region (Northern Spain). The experiment lasted 430days. Statistical differences were found in survival between different thermal regimes but no significant differences were detected within the fall or winter seasons. Daily specific growth rates were significantly different during the summer season with some compensatory growth patterns being observed in the natural thermal regime set up. Likewise, statistical significances were found between the fat contents from both temperatures after the summer period. Conversely, no significant differences were observed at sensorial level between the samples obtained within our pilot experiment and commercial samples from wild origin. Electricity use was found to be one of the most significant economic costs to be considered. The present study represents the first technical feasibility attempt on cod in land-based aquaculture from the north of Spain and demonstrates the technical feasibility to produce on-land based cod in the region, the equivalence of growth patterns with previous studies, the usefulness of the proposed thermal regime management as a tool for this species production, and the key economic parameters and thresholds for a potential feasible commercial activity in the region. Statement of relevanceThis contribution is of help for the modelling and decision-making for on land based recirculating aquaculture initiatives.