Image copyright Reuters Image caption Thailand is the world's third-largest seafood exporter

More than 100 people have been arrested in a crackdown on abuses in Thailand's multi-billion dollar seafood industry, officials say.

Last April the European Union threatened to boycott the industry unless it tackled illegal fishing and allegations of human trafficking.

On Monday, police said a taskforce set up since had investigated 36 cases and also rescued 130 trafficking victims.

Thailand is the world's third largest exporter of seafood.

Human rights groups have long highlighted abuses in the Thai industry, saying it is reliant on illegal fishing practices and overfishing, and involves trafficked workers from neighbouring countries who, they say, work in conditions akin to slavery.

Deputy National Police Chief Thammasak Witcharaya said that in the 16 months prior to the task force being set up only 15 cases were investigated, insisting that the crackdown had intensified.

He added that nearly all of the 102 suspects arrested were prosecuted and 36 sent to prison.

Analysis: Jonathan Head, BBC News, Bangkok

The problems in Thailand's seafood industry are complex and will not be solved quickly even with determined government effort.

There is the challenge of properly licensing thousands of fishing boats and reducing the fleet to a more sustainable size, but also of regulating a fragmented processing industry, one of the word's biggest, where endemic labour abuses exist.

Then there is the illegal but very profitable business of trafficking migrants through Thailand.

While these arrests are an improvement on previous years, it must be viewed in that context; it is progress, but limited.

The revelation last November that even a global brand as big as Nestle had discovered evidence of slave-like conditions in parts of its Thai supply chain is an indication of how deep-rooted the problem is.

The Thai military government, desperate to improve its ranking in the US annual trafficking report and to avoid an EU ban, seems willing to act. The real test will be the prosecution of those who are running illegal businesses.

Last year the inclusion of a senior military general among 88 people charged with trafficking was seen as a breakthrough, but Thai judicial procedures are slow.

Most damaging was when the police general who had led the anti-trafficking drive sought asylum in Australia in November. He claimed his superiors actually obstructed his work, and that a forced transfer to southern Thailand would have put his life at risk from trafficking networks.

The EU's warning to Thailand last April said it would block seafood imports unless Thailand implemented a tailor-made action plan within six months. About 15% of Thailand's seafood exports are destined for the EU.

Image copyright ILO Image caption Thailand says has insisted it will be able to tackle the abuses

The US also has Thailand on a blacklist for failing to do enough about what it called "persistent" labour abuses in the seafood sector.

Thai authorities have consistently said they are tackling the abuses and are confident they can address international concerns.

Rights groups have said that fishermen from Cambodia and Myanmar - also known as Burma - are trafficked and forced to work on the boats, and also highlighted the use of children working in the industry.