When a large and rarely seen squid became entangled in a gillnet in the waters off Pakistan recently, it was a fisherman who came to its rescue – thanks to special training in dealing with accidental catches.

In a video posted earlier this month by WWF-Pakistan, fisherman Hadayat Ullah can be seen carefully disentangling the animal before throwing it back into the water. Ullah is one of a small (but growing) number of local fishermen who have been trained to safely release animals unintentionally caught in their nets. 

"WWF-Pakistan has trained about 50 fishermen to release bycatch species," explains the organisation in a Facebook update.

Pakistan’s coastal waters teem with fishing boats, and their gillnets, mostly intended for tuna and mackerel, frequently snare other marine creatures, including whale sharks, dolphins and endangered turtles. 

To combat the bycatch problem, WWF-Pakistan has spearheaded a training and awareness initiative to teach local gillnet fishermen about the importance of releasing non-target species.

This latest rescue was a diamond, or rhomboid, squid (Thysanoteuthis rhombus), a species that rarely makes an appearance in these waters. Named for their long, triangular-shaped fins, the animals are fished in other parts of the world, including Japan, but they're not a target species in Pakistan. "It was reported in Pakistan for the first time in 1995, but due to its rare occurrence, it is not commercially exploited," explains the WWF. 

Diamond squid can reach over a metre (4ft) in length and weigh as much as 30 kilograms (66lbs). And while the species can be found in tropical and subtropical waters across the globe, it very rarely shows up in Pakistan's waters. "This squid is of very rare occurrence in Pakistan and only a few specimens of this species were previously recorded," adds the group.

In fact, according to the group's Muhammad Moazzam Khan, this is possibly the first time a diamond squid has been caught alive in the region, making it a particularly noteworthy sighting. The animals play an important role in open-ocean ecosystems, preying on fish and invertebrates like marine crabs.

For the WWF, releases like this one are both a win for marine conservation and proof that their training efforts are paying off – particularly when fishermen like Ullah choose to return their bycatch to the ocean instead of potentially selling it for a profit.

Elusive cephalopods like this diamond squid are not the only animals benefiting from the training programme. In recent months, fishermen in local waters have released other entangled creatures, including rayssunfish and even a rare Longman’s beaked whale.

As for the diamond squid, the animals put on their best show when it's time to reproduce. Their free-floating, gelatinous egg masses can reach around 2m in length, with as many as 40,000 eggs laid together: