A video filmed by a snorkeler that reveals fish and shellfish, dumped overboard by a bottom trawler on Scotland's west coast has gone viral on social media.

The film, which shows the heads of thousands of dead prawns - whose tails have mostly already been removed to be processed and sold as scampi - scattered across the seabed, also reveals other fish discards.

Amongst them are five different species of shark, including flapper skate, which is internationally critically endangered, but has a stronghold where it survives in Scotland.

The diver who filmed the footage, marine ecologist, Peter Hume of Sea Kintyre, said: “I was contacted by Shark and Skate Scotland after they had received a tip-off about suspicious fishing activity. I hopped on the ferry to Gigha, to see if the reports were true. Sadly, they were; all around the pier there were mountains of discarded skate and langoustines."

Campaigning groups Opean Seas and Shark & Skate Scotland, in a press release, say the film, which has been viewed nearly 150,000 times, "exposes the hidden problem of discarding at sea that continues to beset the scampi industry and causes unsustainable harm to marine life". 


Nick Underdown, Head of Communication and Campaigns at Open Seas said: “The environmental impact of bottom-trawling is usually hidden from public view, but this footage shows the grim reality of bottom trawling for scampi. Bottom-trawling is a largely indiscriminate method of fishing, but most people have no idea that their scampi and chips are caught using this method and at such an environmental cost."

"Last year," he observed, "the Scottish Government proposed deregulating rules on discarding even further, but this incident shows that the industry needs better regulation not less, if it is going to become more sustainable. A good start would be to put robust vessel tracking on inshore prawn trawl boats so poor practices like this don’t undermine the wider reputation of the industry."

The majority of identifiable specimens of skate in the footage are, according to the campaigners, thornback skate of both sexes, spotted skate and three critically endangered flapper skate. There are numerous small-spotted catshark,  as well as a black-mouth catshark.

According to a recent study published in ICES Journal of Marine Science, bottom trawling has the highest level of by-catch of any form of fishing.

The campaigners say that this unintended bycatch is a particular problem in the prawn trawl fishery due to the small mesh size of the nets.

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On the west coast throwing away prawn heads, often after 'tailing' on-boat,  is permitted, but discarding bycaught fish such as cod is illegal. Since 2019, all fish - subject to a few exceptions - must be landed and declared at port, under the ‘Landing Obligation’.

The law requires that although accidental bycatch is not a crime, all skates and rays must be “released immediately” as they are more likely to survive. The incident was reported to both Marine Scotland and Police Scotland by Mr Hume. 

Exactly how endangered the flapper skate continues to be in Scotland is sometimes disputed - and some fishermen responded to the video online by questioning the merit of the 'critically endangered'  classification. Others posted online images of their own prawn hauls without any signs of bycatch. 

Lauren Smith of Shark and Skate Scotland said: “The historical range of flapper skate has been severely reduced in recent decades due to overfishing and Scotland’s inshore waters are now a vital stronghold for the species. It’s vital that we protect fish like these from the impacts of bottom-trawling.”