Swordfish

Swordfish -   Scientific name - Xiphias gladius

Conservation status

Swordfish are a species under threat.

The IUCN assess Swordfish  as Near Threatened.  They state the fish ‘is estimated to have declined by at least 22% over the past 20 years’, although stocks have increased in the North Atlantic: ‘Overfishing is occurring in the Mediterranean and the South Atlantic stocks, which are estimated to account for at least 25% of this species' global population’. (IUCN)

They are listed on the Greenpeace Red List.

They say ‘Swordfish is primarily targeted using longlining. This technique unintentionally catches and kills significant numbers of other species. The South Atlantic stock status is uncertain and only Eastern Pacific Ocean stocks are considered to be relatively healthy.’(Greenpeace).

Of the 12 assessments from the MCS, only 2 fishing areas are given the Best Choice rating.  (These cover certain North Atlantic fleets and South West Pacific fleets which are Marine Stewardship Council (MSC) certified).  Of the other areas,  7 are In Need of Improvement and 3 to be Avoided.

Overview

The Swordfish is named after its long pointed, flat bill, which looks like a sword.

They have a powerful, torpedo-shaped body, and are typically dark on top, transitioning to silvery or white on the underside. They are found in tropical and temperate oceans worldwide. 

They typically reach 3 metres in length although have been reported over 4 metres.

It is often said that Swordfish skewer their prey using their long sword like nose. However there is little evidence supporting this. More likely they use their nose to slash at their opponents to weaken them.

Their other strength is their speed and agility and they are amongst the fastest fish in the water.

Swordfish swim alone and don’t school. They can often be found basking at the surface of the sea or jumping – also called breaching - out of the sea.

Swordfish frequent depths of 550 metres or deeper during the day. They feed on a diverse range of fish including mackerel, barracudinas, silver hake, rockfish, lantern fish and herring. Large prey are typically slashed with the sword, while small are swallowed whole.

They have fewer predators than most. Killer whales, sperm whales  and short fin mako (a very fast type of shark) are common predators, but perhaps it is humans who are their greatest enemy and are threatening their existence.

Humans enjoy Swordfish as the meat is firm and makes large steaks. It can be cooked in ways more fragile fish cannot - such as on skewers or on grills.

Swordfish typically live for around 9 years although some have been found to live up to 14 years. They can be traced back to the Eucene period (56 to 33.9 million years ago).

Sources

IUCN. 2025. The IUCN Red List of Threatened Species. Version 2025-1. https://www.iucnredlist.org. Accessed on [16/06/2025].

https://www.iucnredlist.org/species/23148/46625751

Green Peace - http://www.greenpeace-fishforlife.50webs.com/redlists.html

Wikipaedia - https://en.wikipedia.org/wiki/Swordfish

Marine Conservation Society - https://www.mcsuk.org/goodfishguide/species/swordfish/?search=swordfish