Cabinda is the smallest of Angola's provinces and one of its poorest.
At first light, fishermen drag their narrow wooden boats into the shallow water of the grubby shoreline to offload their catches into plastic buckets.
Cabinda's main fish market soon becomes a carpet of glistening silver and pink bodies piled high in mounds on plastic sheets, and the smell hangs heavy in the damp morning air.
Women wrapped in brightly coloured cloth, many with babies strapped to their backs, shout out the prices and, once the deals are done, the fish are taken to be scaled and rinsed in the sea, ready to be laid out for sale on wooden trestle tables.
It is a noisy and high-spirited scene, with a confusing mix of languages: Fiote from Cabinda, Portuguese from Angola, and Lingala and Kikongo from the Democratic Republic of Congo (DRC), plus a smattering of French.
Fishing is the lifeblood of Cabinda, a small exclave of Angola separated from the rest of the country by a thin sliver of the DRC, but fish stocks are falling, people say, and the industry is in decline.
"There's no money in fishing. There used to be big profits to be made but not any more," said João Mavinga Tomas, from the local fishing association.
"The fish are only appearing far from here so you have to go very far to find them and that is expensive."
The 36-year-old pointed to the hazy horizon – and to the row of oil platforms, production vessels and brightly burning orange flares. "Where you have oil exploration, you don't have fish because they stay around the platforms and we are not allowed to go there for security reasons, so we must travel elsewhere for our catches."
Oil has turned post-war Angola into one of the world's fastest growing economies and Cabinda, which produces a daily average of 500 000 barrels, is the source of nearly a third of its very lucrative export.
American energy giant Chevron, working in Angola as the Cabinda Gulf Oil Company, has been in Angola since the 1970s and runs all the operations in the exclave.
Besides its offshore rigs and production units, the company has a large onshore base known as Malongo, a fenced-off, high-security, developed world oasis dominated by American and South African accents.
But for all the liquid gold and associated development, Cabinda remains one of the most under-developed regions in Angola.
A large portion of the population lives in wooden huts without running water or electricity and, beyond the provincial capital, there are few tarred roads and limited health services.
The high number of foreign oil workers passing through Cabinda has created a false economy, pushing up prices, which were already high because its imports must come in by road from the neighbouring Congos.
And the cost to the environment also appears to be adding up.
Tomas said that when there were bad spills Chevron paid out cash compensation to the fishermen in the areas affected, but the money was never enough.
Fish-seller Madalena Jorge (48) said: "I've been selling here for 24 years and things have changed a lot in recent times. Mainly, fish has become very expensive because the fishermen are having to go very far to find a decent catch because our sea here does not have fish … which means we are selling less and this affects all our livelihoods and our families."
At another beach a few kilometres away, where the sand is stained a grimy black and the water is a murky brown, motor mechanic José Simba (47) also complained about pollution. "You do get quite a few spills and it drifts on to shore. It has reduced the number of fish. There are definitely not as many as there used to be.
"You can see the colour of this sand. That is because of the oil that washes up from the water.
'I remember 25 years ago when this sand used to be whiter than you could imagine and the water was crystal clear, but not any more."
The claims that the oil industry has reduced the fish stock are anecdotal and without scientific backing, but data in the formerly Marxist Angola is extremely hard to come by, especially when it relates to the oil industry where billion-dollar contracts are obfuscated by confidentiality clauses.
For the past 20 years, Norway's Institute of Marine Research has carried out detailed assessments of fish stocks and marine conditions from Pointe Noire in the Republic of Congo to Cape Town.
But the Angolan ministry of environment said it did not know how to access that data and it could not provide details about how many oil spills there had been or their size.
By law, all spills must be reported to the ministry of petroleum, which then informs the ministry of environment and, depending on the size of the spill, the ministries of fisheries and defence.
International companies are legally obliged to clear up their own spills and, if they are unable to do so, they must seek help from other commercial operators.
Santos Virgilio, an adviser to the environment ministry, said: "In 2002 there was a large oil spill in Cabinda and Chevron was fined $2-milllion.
"That money went partly to compensate fishermen but also to create a research laboratory in Cabinda. [But] I am not sure [whether] that is yet fully operational."
Virgilio disputed the widely held belief that the sand was stained by oil, saying a 1995 ministry study found it was caused by the high levels of sediment and silt coming from the nearby Congo River.
A separate study of a dead mangrove forest found the cause was related to a lack of water circulating because of a coast road that had been built in colonial times and recently upgraded.
I asked Chevron a number of specific questions about its environmental record in Cabinda, how many spills there had been, whether it had been testing water quality and about the compensation scheme for fisherman.
I asked about a spill earlier this month on Mandarim Beach, about 40km north of Cabinda City, where I saw a team of Chevron employees collecting contaminated sand in yellow hazardous-waste bags.
I also asked about photographs I had seen of large patches of detergent foam, thought to be from oil dispersant chemicals, washing up on the beach and the pictures shown to me of a dead olive ridley turtle.
Chevron refused to answer these questions and referred me to its 2011 corporate social responsibility brochure, which is full of glossy photographs of smiling children next to the company's red and blue logo. The words "spill" and "pollution" do not appear once in the 32-page document.
James Craig, Chevron's media adviser for Africa and Latin America, said that, despite the local team having collated answers to my questions, after discussions with company officials in Houston, he had not been authorised to share them.
Quoting from existing corporate literature, he said: "Chevron invests in the prevention of incidents and environmental damage, as well as in responses to mitigate the impact when incidents happen.
"Above all, the safety of the people and the communities where it operates comes first. When a spill occurs, Chevron reacts immediately, even if the origin of the spill is not in the company's operations.
"Our spills rate is low and has been decreasing over the years. We have a world-class performance in the spills/production ratio."
Craig said that Chevron directly funded a scheme to support local fishing communities that facilitated access to credit and facilities and aimed to improve the "economic profitability" for communities.
The brochure referred to millions of dollars being spent countrywide on supporting community, education and health projects as well as funding various microcredit schemes to help fishermen and farmers.
But despite this investment, many people in Cabinda and Luanda are suspicious about the claims. They say Chevron is trying to cover up its poor environmental record by promoting other schemes.
Cabindan lawyer and journalist José Manuel reports regularly for the Voice of America about oil spills that wash up on the beaches and kill plant life and fish.
He said that when spills occurred fishermen received only token financial compensation from Chevron, which did not equal their real losses, and anyone who complained was "bought up" and silenced.
Unusually, the state-controlled government mouthpiece Rádio Nacional de Angola broadcast a story about the clean-up incidents I witnessed in September.
But it said the spill had come from neighbouring oil-producing countries, and was brought to Cabinda by the tide.
Cabindan Raul Danda, an MP for Angola's main opposition party, Unita, said: "Oil production always creates problems for the environment.
"The people used to make their living from fishing but now they are losing that because of the oil. Not only are they not seeing the benefit of the oil revenues, they are also living with the associated environmental impacts."
Danda said the government should be doing more about the negative environmental impact of oil production, enforcing legislation and holding companies to account.
"When these spills happen, the government says nothing and does nothing. There is this real culture of secrecy between the government and oil companies.
"I personally think it is because they don't want people to find out the true extent of what is going on as that might leave them vulnerable to legal claims or other issues.
"For me, the fact that Chevron does not want to share specific environmental information makes you think they must be hiding something."
Virgilio saw no reason for a cover-up but admitted there was a lack of institutional capacity in Angola to provide information and data.
But Danda said the history of Cabinda, which has been at the centre of a long-running separatist struggle, was key to making sense of the environmental situation. "The day that the oil starts to run out in Cabinda is when the autonomy talks will really start."
Danda has been arrested and detained because of his association with the Cabindan civil society organisation Mpalabanda, which is banned because of its alleged links to the Frente de Libertação do Enclave de Cabinda.
"Once they've got the oil, they'll have no more use for Cabinda and will want to get rid of it," Danda said. "That is why they don't care about the environment and why they are investing so little there.
"Cabinda is a colony of Angola and it is treated like the worst kind of colony. The lack of respect for the environment and its people is proof of that."
Army presence keeps locals in their place
Cabinda is Angola's smallest province, covering 7000km2 (less than half the size of Gauteng), and is physically separated from the rest of Angola by a thin strip of the Democratic Republic of Congo (DRC).
For decades, it has been at the centre of a separatist struggle based on claims that, although Angola was colonised by Portugal, Cabinda was an overseas Portuguese protectorate and thus should not have been incorporated into Angola when the country was granted independence in 1975.
The struggle has been led by the Frente de Libertação do Enclave de Cabinda (FLEC), which has kidnapped foreign oil workers and clashed with the Angolan Army, the Forças Armadas Angolanas.
In 2006, a so-called peace deal was signed that led to the then FLEC leader Antonio Bento Bembe being included in the government. It was supposed to end the insurgency but a part of the FLEC said Bento Bembe was not their leader and rejected the deal.
Low-level attacks continued, albeit rarely reported because of the absence of non-government media in the province and government efforts to suppress information, but in January 2010 that changed. FLEC gunmen opened fire on a bus carrying the Togo football team on its way to the Africa Cup of Nations, killing several and injuring many others, including English Premiership star Emmanuel Adebayor.
Several civil society academics and lawyers were jailed for "crimes against state security" for supposedly masterminding the attack, although they were later cleared on a technicality. But several rural farmers were sentenced for the crime.
Since 2010, the army has carried out a number of strategic raids on FLEC strongholds in Cabinda, and also across the border in the Republic of Congo and the Democratic Republic of Congo.
In recent months, captured FLEC soldiers have been paraded in state media. They claim they were forced into the struggle and could not escape.
FLEC leaders have appealed to the Angolan government to enter into negotiations and behind-the-scenes talks are understood to have begun, although their aim is not clear.
The presence of FLEC has led to Cabinda becoming one of the most militarised parts of Angola. Soldiers man roadblocks at several points on the main road and ad hoc military camps are set up in forests, near villages and on beaches.
The government says their presence is to control the province's porous borders with the two Congos, but locals say they are being watched and their movement in the province is restricted. – Louise Redvers