We stopped at small restaurant on the Portuguese coast and were slightly confused by an English translation that read ‘swordy fish’ we asked the waiter – our fumbling Portuguese to his broken English -and he confirmed it was ‘sword fish’. When it arrived, it had the shape of a large eel (one of my favorite fish) and texture of halibut; no swordfish but tasting like halibut. In a market later we discovered this was a black scabbardfish – a predature-looking creature with rows of fngs and huge eyes.
The black scabbardfish, a fascinating creature of the ocean depths, displays a remarkable behavior pattern. By day, it resides in the bathypelagic zone, lurking in the profound darkness. But as night falls, it ascends from the depths, venturing into the middle layers of the water column in search of sustenance. Its diet consists primarily of crustaceans, cephalopods, and fellow fishes, particularly grenadiers, codlings, and naked heads. Among its companions in the vast expanse of the ocean is the Aphanopus intermedius, commonly known as the intermediate scabbardfish.
Characterized by its sleek, elongated form, adorned with a pointed head and an elongated dorsal fin, the black scabbardfish is built for speed. Its large terminal mouth, equipped with formidable fang-like teeth, ensures efficient predation. To blend seamlessly into its surroundings, it sports a striking coppery-black hue with an iridescent sheen. The enormity of its eyes, occupying approximately 18% of its head length, serves to enhance its vision in the dimly lit abyss. Sexual maturity is attained at a length of approximately 80 cm (31 in).
This enigmatic species holds significant economic importance for fisheries, particularly those associated with the Iberian Peninsula, notably the Madeira Islands. Here, it is highly prized for its flesh, fetching premium prices in the market. Similar sentiments are echoed in regions around Iceland, France, Ireland, and certain areas of the Canary Islands. In Portuguese waters, traditional methods employing line gear are employed for its capture, while trawlers dominate the Atlantic waters around France and Ireland.
The black scabbardfish stands as a cornerstone of the economy in regions such as Portugal, where it ranks as the most valuable deep-water fish. Over the years, its annual landings have witnessed a substantial increase, reflecting its enduring popularity in culinary circles. From modest figures in the late 20th century to a staggering 6000 tonnes in recent times, its significance in both Madeira and mainland Portugal cannot be overstated.
However, amidst its economic prowess lies a looming threat—overfishing. Existing primarily at depths ranging from 800 to 1300 meters, the black scabbardfish is often ensnared in mixed trawl fisheries, rendering it highly susceptible to depletion. The Marine Conservation Society has sounded alarm bells, assigning it the highest level of importance on the sustainability chart. Urgent measures for its preservation are thus warranted to safeguard its pivotal role within the ecosystem.
Despite its abundance, certain regions of the Northeast Atlantic have witnessed a decline in its numbers, signaling a pressing need for concerted conservation efforts. Balancing economic interests with environmental sustainability remains paramount in ensuring the continued existence of this remarkable species. As the black scabbardfish navigates the depths of the ocean, its fate intertwines with that of the marine ecosystem, underscoring the delicate equilibrium that sustains life beneath the waves.
