At the centre of the ritual is the belief is that returning animals to the wild is good karma - or action.
But the pair found themselves in hot water after it emerged that the crustaceans were not native species and their act at kindness in fact threatens to cause "untold damage" to marine life in the area.
The Marine Management Organisation (MMO) has paid out thousands of pounds trying to recapture the shellfish - offering local fishermen a bounty of £20 to reel them back in.
In the first case of its kind Miss Li, 33, a City banker, and Mr Li, 30, an estate agent, both from London, pleaded guilty to releasing non-native species into the wild.
Joseph Miller, prosecuting for the MMO, told Brighton Magistrates' Court that the incident came to light after a Brighton fisherman captured some of the foreign shellfish in June 2015.
An inspection of Brighton Marina's CCTV subsequently showed the group chartering three boats. after having bought more than £2,500 worth of native crabs and lobsters from Shoreham Harbour.
Investigators then found that 361 American lobsters and 350 Dungeness (US) crabs had been bought by Miss Li from a wholesale fish supplier SeeWoo, in Greenwich.
The court heard that Miss Li later lied to investigators, saying she had not realised the crabs and lobsters were foreign species and had taken them back home and kept them in a bath of saltwater. She later admitted she had made up the story.
Mr Miller said "Ni Li brought them from London then they went out on three boats and released them into the water. [Zhixiong Li] said he knew it was an offence to release non-native species but said he thought they were native."
So far just 323 of the foreign crustaceans have been recovered and the most recent American lobsters found had been carrying "viable eggs", showing they had been breeding.
It emerged that Ni Li and Zhixiong Li had bought so many non-native species because they had to source them on the day rather than order them in advance.
To have pre-ordered them would have led to hundreds of them being captured to meet the spike in demand, in direct contravention of their beliefs.
Mr Li said he had asked [the boat's owner] David Ross if he had to report the release to any authority and claimed he was told this was unnecessary as long as the animals were local.
The pair said that had they been aware the crabs and lobsters could do such significant harm to the environment they would not have gone ahead with the ceremony.
Paul Tapsell, defending Mr Li, said: "He accepts that in releasing these crabs and lobsters he in fact did the exact opposite of what he wanted to do."
Tim Ryan, defending Miss Li, said: "Without a doubt she is a bright, hard working and intelligent young woman who takes on too much in a voluntary capacity. She is perhaps a little naive and that's what's got her into this business."
Miss Li was fined £5,300 and Mr Li £500. They were also ordered to pay £9,000 compensation.
District judge William Ashworth said: "The full impact of what you did is not known. Clearly this was not your intention. There was no deliberate sabotage, but both of you were at the very least negligent. You had between you a certain amount of knowledge about what you could and could not do and you both told untruth to the investigators."
The MMO said that the lasting effects of the ceremony may never be fully known and warned that the local fishing industry could lose out as a result of the crustaceans killing native species.
- Additional reporting: Oliver Price
This article originally appeared on the Daily Telegraph.
