This species is taken as bycatch by demersal trawls and longlines throughout large areas of its geographic range. It is generally discarded, but is retained and utilised in some areas.

Northeast Atlantic
Although a large portion of the population of G. melastomus avoided most of the commercial fishing pressure associated with the 1970s deepwater trawl fishery for Blue Ling (Molva dypterygia) in the northeast Atlantic at >600 m, it is concerning to note that mature individuals of this species are found at similar depths to the shallowest depth range of this fishery, and that commercial deepwater trawl vessels are now targeting these sharks. The targeting of mature individuals of this species may lead to similar detrimental impacts experienced by other deepwater species in this area (Crozier 2003).

Off the south coast of Portugal (Algarve), this species is captured in high quantities as bycatch of the bottom trawl fishery that targets the Norway Lobster (Nephrops norvegicus), Red Shrimp (Aristeus antennatus) and Deepwater Pink Shrimp (Parapenaeus longirostris), and by the near bottom longline fishery that targets European Hake (Merluccius merluccius), Conger Eels (Conger conger) and Wreck Fish (Polyprion americanus). In both fisheries, most captured specimens are discarded (Coelho et al. 2005). Most specimens are captured and returned to the sea alive, but usually with severe injuries (due to the long trawling periods or hooks) that are likely to impair their survival. However, declines in traditional target species during the last few years mean it is likely that fisherman are now landing larger quantities of “alternative” species, such as this catshark, so it may be increasingly retained and sold.

Mediterranean
The species is caught as bycatch by trawl nets and bottom longlines on slope bottoms. The species appears to suffer greater fishing mortality in the Ionian, south Adriatic and Aegean Seas, compared to along the coasts of Morocco, Spain, France and around Crete. Length Frequency Distributions (LFD) show that along the coasts of Morocco, Spain, France and around Crete specimens were mostly larger than 30 cm (78% of the total), while only 23% of the specimens around the coasts of Corsica, Sicily and in the Ionian, South Adriatic and Aegean Seas were over 30 cm (Serena et al. 2005).

It seems that this species suffers relatively moderate effects from fishing pressure in the south Ligurian and northern Tyrrhenian sea, although it is an important bycatch of the Norway lobster Nephrops norvegicus fishery.

G. melastomus constitutes a significant portion of the bycatch of the Viareggio fleet’s fishing efforts, but most of the individuals are discarded due to the limited market demand and low commercial value. Only a fraction of the larger individuals (TL>40 cm) are landed at Viareggio (about 700 kg in 2002) (Abella and Serena 2005). Considering the depths at which G. melastomus is caught (250–800 m) and the observed poor condition of the individuals immediately after their capture, it is likely that only a small fraction of the discarded individuals survive. However, it should be noted that the fishing grounds for the Viareggio fleet coincide only partially with the areas where G. melastomus is known to be abundant, and that higher densities of this species are found in deep waters off northern Corsica, where the fishing pressure is moderate. These areas could therefore act as a refuge for this species (Abella and Serena 2005).

In the Alboran Sea, where this species is very abundant, G. melastomus is the most important bycatch species in the recently developed bottom trawl fishery targeting the Deepwater Shrimp (Aristeus antennatus) (Torres et al. 2001).
The recently developed ban on bottom trawling below depths of 1,000 m in the Mediterranean Sea probably offers this species some refuge from fishing pressure.