On July 5, Ghanaian fisherman Essien went missing from the Meng Xin 15 trawler off Accra coast. Is brother James says that Essien had dinner with the rest of the crew of the Chinese vessel before they headed back to their cubicle to sleep. The next morning, he was nowhere to be seen.

More than three years on, the family still has no answers. A police investigation found “no signs of violence or anything incriminating”.

“I want the truth to come out,” James tells the BBC, in tears.

The Mengxin Ocean Fishery Company could not be reached for comment. Essien’s disappearance is one of many factors that have had a chilling effect on Ghana’s fisheries observers. Ghanaian observers who spoke to the BBC explain how a culture of fear, corruption and neglect are pushing them to take bribes to bury evidence of illegal fishing and abuse on Chinese vessels.

“Most of our colleagues are taking money,” says one observer, who requested anonymity and we will call Daniel. “They are being bribed and taking money from the Chinese and submitting reports to the ministry that are not true.”

All the observers interviewed say their wages are poor and it often takes as long as five months to get paid, meaning kickbacks from Chinese and Ghanaian crew managers are necessary to feed their families.

“If you reject the bribe you go home hungry,” says another observer, who we will call Samuel. “Most of those observers do take bribes. That’s what we do to take care of our families.”

Some feel too scared to report the truth.

“Sometimes what they do is throw the observer into the water – it has happened before,” Samuel says. “Because of the fear we normally don’t report issues like that.”

One former observer, who has since left Ghana, tells the BBC he was once called to the office of a high-ranking official within the Ministry of Fisheries and Aquaculture Development after he reported illegal practices at sea.

He says the official asked him to present the evidence, and then proceeded to delete it from his phone. But he had the evidence backed up on a laptop and threatened to post it on social media. Then he says he started receiving threats.

At one point he was so nervous that he would not sleep at his own house because people knew where he lived and he was worried about being attacked, or worse. One day, when he was cycling near the fishing harbour in Tema, a port city east of the capital Accra, he says a Ghanaian official spotted him and tried ramming him with his vehicle.

“He was trying to hit me with his car at the fishing harbour. I saw him so I jumped to the gutter… this guy was mad,” he says.

He eventually decided to leave the industry after receiving death threats.

“I became miserable in life because when I’d go to the harbour, everyone was looking at me. I couldn’t find any work to do. I became like a stranger, like I’m a bad person. It was so hard for me.”

He now avoids the harbour when he’s back in Ghana.

“People try to threaten me. These guys are very serious,” he says.

Steve Trent, founder and head of EJF, says the high concentration of Chinese ownership within trawl fleets is a problem across West Africa, accusing them of often flouting the law.

But in Ghana, the problem is “particularly acute”, he says.

“These Chinese owners have commonly put a Chinese captain in charge of the vessels to command the mainly Ghanaian crew and it is these Chinese captains that have driven the abuse,” Trent says. He blames the abuse on the owners seeking to “maximise profits and minimise costs”.

EJF investigations have uncovered systemic corruption “at virtually every level and including fisheries officials, police and navy officers” tasked with enforcing regulations, he says. While there has been some progress on illegal fishing in Ghana, Mr Trent says a lot more needs to be done.

“We need to see the loopholes and deceit by which illegal foreign ownership, now concentrated with the Chinese, are eliminated,” he says.

The Ghanaian government did not respond to multiple requests for comment. Kweku wants the government to allow fishermen to properly unionise, and says a system must be put in place so people are under contract before being sent out to work at sea. A mixture of abuse, disappearances and poor pay has taken a lasting toll on his mental health, and that of many others.

“We lost a lot of fishermen at sea but nothing is done about that. Two or three observers are missing,” he says.

“We are all afraid of going to sea but there is no work on land, so you must force yourself to go.”

• A BBC report