New Era reports that Mr Esau made the statement during a consultative meeting convened on Wednesday (5 June) with the Midwater Trawlers Association at Walvis Bay.
He recalled an incident in 2008 when a company was penalised for dumping fish in Namibian waters and said that similar action would be taken against any company persisting in the same practice.
Recent media reports reveal that a Chinese company was recently fined N$1200 for dumping fish. The minister said that the fine would be revoked.
Mr Esau said: "A fully fledged investigation will be launched into the incident and the guilty parties will be fined accordingly."
Mr Esau said that such acts would not be tolerated since the country is well-known for its sound fisheries management regime.
"We cannot afford to compromise the country’s image at all. Those companies that are dumping fish at sea, we will consider their rights and quotas in terms of suspension, cancellation, downgrading and eventually allow their rights to expire. In addition, stern measures will be taken against those operators," Mr Esau said.
He also expressed concern over foreign flagged vessels operating in Namibia and called for local fishing right holders to invest in trawlers.
"Since 1991, all vessels fishing in the Namibian mid-water industry are foreign flagged vessels. This is not promoting the Namibianization of the sector at large. We need to discuss this issue at length and encourage companies to get into the culture of owning vessels," the minister said.
Mr Esau also threatened to cancel the fishing rights of joint venture companies (JVCs) fighting each other. According to him, JVCs tend to withhold quotas from each other or fight over quotas and even change shareholding structures without informing each other.
"Information of day to day operations within joint ventures is also not shared with each other. Some shareholders are trying to marginalize the ones that are already marginalized. I will not entertain such behaviour and will cancel your rights. We cannot tolerate people who are selfish," he said.
"The culture of not sharing information with partners is not welcome, as this creates tension and brings about mistrust. This, therefore, concerns government," Mr Esau said.
He said joint ventures will start going through a screening process to see if they lived up to the government's expectations and to ascertain whether they will qualify for the reserve quota allocation of 80,000 tonnes for horse-mackerel.
"The purpose of setting total allowable catches (TACs) and the allocation of quotas is for the economic development of Namibia and it is allocated to the right holders to contribute to our economy and not to fight among each other," he said.
"As a minister I will not tolerate such behaviour. I will cancel your rights with immediate effect. Greed will certainly not be entertained by my ministry."