Hake is one of the most commercially valuable species in the Bay of Biscay and the north-east Atlantic. Its capture sustains a significant portion of the activity of the Spanish and European professional fishing fleet. As a result, hake fishing with longlines has become one of the most efficient and selective methods for targeting this species in deep waters.
Unlike trawling, longlining allows for more controlled catches, with less impact on the seabed and greater size selectivity. However, its performance depends largely on a factor that is often underestimated: the behaviour of the weight on the seabed.
What is bottom longlining and how does it work?
Bottom longlining is a fishing method consisting of a long horizontal mainline, from which a series of snoods or branch lines hang at regular intervals, each ending in a baited hook. The line is fixed to the seabed by anchors at both ends and maintained at the working depth by weights distributed along its length.
In bottom longlining targeting hake, the line can reach several kilometres in length and operate at depths of between 200 and 600 metres — the continental slope zone where this species carries out much of its feeding activity. The rigging, the distance between snoods, and the ballast weight are adjusted according to the target depth, current, and type of seabed.
Hake in the Bay of Biscay: habitat and behaviour
Hake fishing in the Bay of Biscay takes place primarily over the continental slope, on mixed-nature seabeds such as compacted mud, coarse sand, and interspersed rocky areas. Hake is a demersal species that spends the day close to the seabed and rises through the water column at night to feed, which dictates both the fishing schedule and the positioning of the gear.
Its response to bait is relatively active, but its distribution by depth varies according to the season, water temperature, and food availability. During spring and autumn campaigns, the largest specimens concentrate in the deeper areas of the slope, requiring the longline to maintain a stable and precise position along its entire length.
The role of the weight in bottom longlining
In bottom longlining, the weight serves a dual purpose: it ensures that the mainline remains in contact with the seabed, and it controls the distance between the snoods and the substrate — thereby determining the depth at which the bait is presented.
Inadequate ballast — whether too light or of an incorrect shape — can cause the line to rise under the effect of the current, moving the bait away from the zone where hake are active. Excessive weight, on the other hand, makes hauling more difficult, increases wear on the line, and raises the operational cost of each trip.
The key factors to consider when selecting weights for this gear are:
- Density and weight: the working depth and the strength of currents in the Bay of Biscay require high-density weights to keep the line stable without increasing the number of sinkers.
- Corrosion resistance: working at depths of 200 to 600 metres in North Atlantic waters involves prolonged exposure to conditions of high salinity and pressure. The durability of the weight material directly determines the service life of the gear and the frequency of replacement.
- Shape suited to the seabed: on mixed seabeds with rocky areas, the design of the weight influences the likelihood of snagging during hauling. More compact shapes with a lower friction surface reduce material losses and idle time.
- Impact in the event of loss: in large-scale bottom longlining operations, the loss of sinkers is an inevitable factor. The composition of the weight determines whether that loss represents a source of persistent contamination in the benthic ecosystem where the fleet operates.
Fishing weights for bottom longlining: the SARE range from GreenCastSea
For the specific demands of bottom longline fishing, GreenCastSea's SARE range offers solutions tailored to the conditions of the Bay of Biscay and the north-east Atlantic.
The SARE SA model is notable for its robust design and versatility in deep-water applications, with stable performance even in variable current conditions. The SARE ST model, with its cylindrical shape, offers a lower-resistance profile through the water column, facilitating line setting and maintaining stability on the seabed during fishing.
Both models are manufactured from recycled zinc alloy, 100% lead-free, ensuring that accidental material losses during fishing operations do not generate heavy metal contamination on the seabeds where the hake fishery operates.
GreenCastSea: lead-free industrial fishing weights
GreenCastSea is a company specialising in the development and manufacture of eco-friendly fishing weights for the professional fishing industry. All our products are manufactured from recycled zinc alloys, lead-free, and designed to meet the technical demands of industrial fishing on an international scale.
The Itsaspe range, which includes the SARE and HARI lines, covers the requirements of bottom gear, longlines, and nets, with standard models and bespoke solutions adapted to the specific conditions of each fleet and fishing ground.
Beyond technical performance, choosing GreenCastSea weights represents a concrete step towards compliance with international environmental standards and the reinforcement of responsible fishing certifications that an increasing number of markets are requiring of their suppliers.