New threat for Mediterranean swordfish as new trap makes fishing more effective and aggressive

Fishermen in some regions of the Mediterranean, including a few in Malta, have recently started deploying a new trap to catch swordfish that is leading to large increase of catches, something that is causing concern over overfished, beleaguered swordfish populations. Fishermen in Malta told this website that the few Maltese fishermen who are deploying these new ‘traps’ have had catches that are more than 50 percent higher than in normal, floating longlines.

Three Italian scientists who documented this new trap, which they called trapline, in a paper earlier this year also wrote of catches being much higher. The paper was published on the website of the International Commission for the Conservation of the Atlantic Tuna (ICCAT), the inter-state commission tasked with protecting blue fin tuna, Mediterranean swordfishes, sharks, rays and albacore from overfishing. ICCAT is having its annual plenary meeting this week in Cyprus. 

These new traps consist of 6 or 7 rings of monofilament nylon, with the bait placed in the centre, and they are deployed on the same lines as the surface longlines. In the traditional longlines, bait is hooked in hooks attached to the longline.  

A fishermen in Malta described the reason for higher catches to this website. “Many times,” he said, “swordfish circle around the baited hooks without taking a bite. In this new trap, circling swordfish end up being entangled in the rings and get caught in any case. So this is going to make fishing more aggressive – and the population of swordfish is going to be decimated sooner or faster.”

The fisherman spoke on condition of anonymity out of fear of reprisals. He said that traplines are already for sale in Malta, although the few fishermen who are using them are mostly making them themselves.

Overfishing has denuded the population of Mediterranean swordfish, and a decade ago ICCAT began to implement restrictions that culminated in an ongoing multi-year recovery programme that has, among its main measures, a three-month closed season on swordfish fishing and a ban on catching juveniles.  

Yet swordfish fishery is not on the agenda in this week’s ICCAT plenary as ICCAT’s scientists are due to complete a stock assessment before the management measures are reviewed next year.

The three Italian scientists – Fulvio Garibaldi1, Antonio Di Natale, and Bruno Zava – wrote about secrecy surrounding the use on the new gear. The scientists wrote: “The confidentiality that surrounded this new gear for more than two years was very strict and almost absolute, in all countries concerned, until we discovered it.”

The trapline targets swordfish deeper in the water profile than the floating longlines with hooks dangling near the surface. Traplines are deployed as low as 100 metres depth, which is also the starting depth of mesopelagic long lines, which are hooks deployed between 100 metres and 600 metres that mostly target large female swordfishes during the spawning period (there are popularly called the ‘big spawners’).

Contacted for comment by this website, Di Natale lamented about the bad “quality of the information” surrounding the use of the trapline, and the unknowns about its impact. He said it is strange that deployment of the trapline was not reported by the observers – the so-called observers are employed by ICCAT to be present on 5 percent of all vessels that fish for swordfish, and their task is to observe and report on the fishing activity and the catches.

“In Italy,” Di Natale said, “the director general for fisheries wrote in a memo that the trapline is not permitted, but neither strictly forbidden. Yet the coast guard confiscated this gear in some areas, so the memo from the director general was implemented differently in different areas.”

Traplines are now used through Italy, as well as in Spain and Tunisia and Malta. It is not known if fishermen elsewhere in the Mediterranean are using them. 

Di Natale said it is not clear what conclusions can be drawn from the increased catches, and whether the last assessment into the size of the population, or stock assessment, was weak. “It does not mean that the swordfish is a fantastic situation,” he said, “but it could be that the population was underestimated.”

Fishermen in Malta told this website that they do not believe increased catches by the trapline means the swordfish population is larger than estimated, but that the trapline is a more effective way of catching what remains of swordfishes. As indicated above in this article, fishermen base their opinions on the observation that swordfish sometimes swim around the baited hook without biting, but when it comes to the trapline, they get entangled in the rings in any case.  

Meanwhile, closer to the sea’s surface, the concern is over the catches of juvenile swordfish. ICCAT banned the catch of juveniles that are less than 100cm in length from lower jaw to fork tail, and hooks smaller than a certain size are also prohibited. Yet fishery sources say that swordfishes are aggressive and juveniles are still getting caught. And study for ICCAT estimated that the proportion of swordfish juveniles that are caught amounts to 24 percent.

Juvenile swordfishes are openly sold at a large number of fishmongers’ and fish hawkers’ in various regions around the Mediterranean Sea, including in Malta. The sale of juvenile swordfishes is widespread in Malta, and, in response to questions by this website, a spokesperson for the parliamentary secretary for fishes said earlier this year that the department would act against selling of juvenile swordfishes if reports are made. This indicates that there is no proactive enforcement.

These juvenile swordfishes are found at this time of the year, and the NGO WWF has been campaigning for implementation of measures to reduce the catches of juveniles. These include closing the season in October and November.