A spokesman for the Marine Management Organisation said: "The size of the fines in this case recognises the significant risk to the marine environment posed by offences of this nature."
Last week, Ni Li and Zhixiong Li pleaded guilty to the breach of the Wildlife and Countryside Act 1981 at Brighton Magistrates’ Court.
The court heard how on 15 June 2015, Zhixiong Li organised the party and oversaw the release. The lobsters had been bought by Ni Li at a specialist fish merchant in London.
Following the release, the Marine Management Organisation worked with local fisherman to recover a significant number of the animals.
Ni Li was fined £3,500, ordered to pay £9000 in compensation, costs of £3000 and a victim surcharge of £170.00.
Zhixiong Li was fined £500.00, ordered to pay £9000 in compensation, costs of £3000 and a victim surcharge of £50.00.
The compensation was awarded to the MMO to pay for recovering the animals.