The supertrawler just 14 miles off Brighton capable of landing 6,000 tonnes of fish

• Report by ITV News Correspondent Rupert Evelyn

For days, it has been literally sucking fish out of the sea.

This is a rare glimpse into the life of the Margiris, thought to be the world’s second-largest trawler.

For days, it has been tracking up and down the south coast netting vast quantities of fish.

They aren’t lifted out of the water but pumped on-board directly from the net where they are processed and packed for export, mostly to Africa.

ITV News has learned that this Dutch-owned vessel was subjected to an inspection by UK law enforcement officials.

Although no infringements of fishing regulations were found, there are those who would like more questions asked about super-trawlers.

Capable of catching and carrying more than 6,000 tonnes of fish how can it guarantee the sustainability of fish stocks?

And how do they avoid catching protected species?

These are the issues that concern Jerry Percy who represents those who run small fishing boats (NUTFA - New Under Ten’s Fishermen’s Assoc).

He says the boat is chasing herring, mackerel and blue whiting.

"They don't haul the fish aboard, they haul the end of the net up, they put a fish pump on it, they lower back into the water and they pump the fish aboard," he tells ITV News.

"A vessel of this size will have processing facilities on board.

"These vessels are massively efficient.

"I should stress she's operating legally, but our concerns from a small scale perspective is that they can take an awful lot of fish very quickly - and if they do have a negative impact, it's a major negative impact."

He adds: "There's an argument for what the by-catch is [what they're not supposed to land] and we don't know.

"UK small-scale boats were banned from drift netting for sea bass in this area, yet vessels of this size with such massive nets are allowed to fish."

The Margiris sails under a Lithuanian flag but is Dutch owned.

ITV News has sought comment from the company.

Up close, the Margiris dwarfs anything you’d normally associate with fishing.

The efficiency with which it catches fish means she is in essence a floating factory.

Officially described as a freezer-trawler, no one can say with absolute certainty what impact ships like these are having on fish stocks.

But there are many including those inside the industry who rather that this industry was kept afloat without them.

"The reaction to the news that the super-trawler Margiris is off the south coast of England has been astonishing," says John Hourston, of the conservation group Blue Planet Society.

"It's one of those rare occasions when everybody is singing from the same hymn sheet.

"Commercial fishermen, anglers, conservationists, the public, they all want to see these vessels banned.

"Not only are they unsustainable, they leave ecological destruction in their wake.

"Dolphins, porpoises, seals, and huge amounts of fish are all victims of their supersized nets."