According to the international donor support, the Global Environmental Facility, many small island environments share sustainable development challenges. Among the challenges are rapid growing populations, a constantly rising number of tourists, limited freshwater resources, and a fragile marine ecosystem. An example of how the growing human activities impact the local ecosystem, is the discharge of untreated wastewater into coastal areas. This also applies to Zanzibar. So let us listen to, how Professor Mohammed Ali Sheikh from the State University of Zanzibar characterizes Zanzibar's marine environment and the associated environmental risk. Zanzibar coastal community largely depends on marine resources for supporting local livelihoods. Over 30 per cent of the country's GDP depends on marine based economy, including tourism industry and fishing. However, there is unprecedented coastal degradation due to diversified factors including a close population density with 535 people per square kilometer compared to the Tanzanian mainland with 45 people per square kilometer. Zanzibar is among the top three densely populated countries in Africa. There is a mushrooming of beach resorts along the course of the island. Furthermore there is no treatment facilities for municipal waste, which are directly disposed to the coastal environment synergistically synergistically overwhelming the ecosystem health capacity of the coastal and marine ecosystem around Zanzibar. Islands. If we look at the data on the extent of human activity on Zanzibar, we get a picture of the amount of pressure put on the marine ecosystem. Zanzibar has a population of one point three million, and despite a decrease in the fertility rate, the population is expected to increase with about 3 percent per year. Similarly the number of incoming tourists is expected to increase significantly. From the 2016 figure of 378 thousand arrivals in 1985. Only 50 hotel beds were available at the coast. In 2007, there were close to 8000, and by 2017 the numbers had increased to roughly 15000 beds. A study from 2012 found that almost 60 percent of more than the 200 hotels on the island were built closer to the sea than accepted by national regulation. No sustainable solutions such as large scale sewage treatment plants have yet been developed to manage the waste water generated in Zanzibar. Figures from 2010 indicate that around nine to twelve thousand cubic metres of untreated or poorly treated waste water is disposed directly into the sea per day, and today that volume will be even greater. The number of cargo ships entering Malindi port in Stone Town has more than doubled from 2007 to 2014, carrying bottled water vegetables and other food items from the mainland Tanzania. Yet another example of human pressure on the marine ecosystem comes from the increasing demand for protein and high value fisheries products. The volume of fish landed by the fisheries industry has increased continuously over the past decade as shown here. Let us ask marine scientist Peter Anton Staehr from the University of Aarhus, who is part of a research team in Zanzibar, how the increased human pressure is impacting on the marine environment around Zanzibar. Zanzibar is very fortunate from the nature's point of view, that it's a system that gets flushed. Two times every day, you have the tides coming in and cleaning the area. So it's basically very nutrient poor and clean. And that is basically the reason why things have not gone much worse than they have. The beaches are beautiful, the water is clear, and it's not so evident that they have pollution. But still, it's quite obvious that many places in the coastal system, like in the nearest shore regions around the island, that you have seagrass beds which are not doing well. They are overgrown by fast growing algae. There are areas where the corals are really not doing well. You have mangroves which have become partly destroyed by human development, and some of the waters are obviously not as clear as they should be. So I've been fortunate to be with one of your colleagues, Mohammed Sheikh, who took me to a sewage outlet in Stone Town. I know you've been sampling all along the coast of Zanzibar. What are the findings in terms of waste water? Well, we had very interesting findings, because in some areas, they have been exceeded some acceptable level of microbial load as well as other contaminants, like heavy metals. Is it close to the coast? Yes, but we have some cases, even to the remote area in the northern region, where there is many tourism activities, some level of microbial load is higher compared to the acceptable levels. The research team conducted a water quality baseline survey around the island in 2015. As expected the level of nutrients, chlorophyll concentrations and coliform bacteria, were high in the waters close to the densely populated city of Stone Town, resulting most likely from the significant wastewater discharge. Surprisingly the levels of coliform bacteria off the northern and north eastern part of the island were even higher than around Stone Town, suggesting a strong impact from large resorts located along the coastline. Maybe Peter Staehr can explain this phenomenon. Far from the beach, actually several kilometers into the ocean, you had quite high levels, and in other places, even closer to the shore you had much less. Any particular reason? Well the effluence that provide the coliform bacteria are very local sources, because bacteria they get very fast degraded by ultraviolet radiation and so there's lots of sources around the island. So I think we have around 27 known sewage outlets that are untreated water, and on top of this you have settlement and lots of hotels where we don't have any account of how they provide nutrients into the water. Just to give an example, there is a small island on the north part of the out of the mainland called mnemba, and we were sailing there. It's like a paradise island. Bill Gates went there on holiday, and it's beautiful. But that was where we actually measured the highest levels of coliform bacteria. But that's also an area where there's absolutely no management of the sewage. so local sources have huge impact. And if they're not managed properly, then they can provide substantial problems. The problems, referred to by Peter Staehr, not only impact the marine environment but also carries a risk to human health. Contamination of the coastal marine environment by sewage increase the risk of infectious diseases including diarrhea and cholera. These can be obtained by activities such as swimming or consuming seafood. Pathogenic bacteria in wastewater can survive in the sea from one day to several weeks. And viruses can survive in water, fish, or shellfish for even months. The high levels of nutrients in the water may also increase human exposure to toxins connected with algae blooms. Depending on its source, sewage may also contain a range of chemicals, heavy metals, medical waste, and oil products. These results in additional risk to human health. Although the impacts are very difficult to assess. In 2006 the government of Zanzibar required hotels to manage their own sewage properly. But this rule seems to be widely ignored. And since there is no official sewage treatment planned on Zanzibar, the vast majority of hotels use septic tanks or discharge sewage directly into the sea. Marine litter that is really a huge issue. You cannot go anywhere along the beaches where you do not see plastic debris, wood debris, any kind of construction debris. We did a survey along some hundred meter stretches of beaches, using international standards for this, and sorted out all the different types of litter, and there was a lot of plastic. A study conducted by Professor Mohammed Sheikh and his team at the State University of Zanzibar to estimate the amount and composition of litter on the beaches, found that about half of the garbage consisted of plastic, and around a third from textile. We are particularly concerned about the plastic litter. Instead of being biologically degraded to metabolism, plastic is simply divided into smaller and smaller polymer chains. By the effect of uv sunlight. Even though there's no historical data to compare and evaluate changes over time in Zanzibar, let us ask Peter Staehr about the current status of plastic accumulating in Zanzibar. So we investigated along beach stretches, and also in sediments in the water. We took samples to measure in very detail the size, structure, and the composition of the different types of litter. And you do see the very small fragments that is not really visible to the human eye, like less than a millimeter. So they're quite abundant. Also along the shores and in the sediments around the island. And this is something that is of concern. And the numbers that we are getting, are suggesting that they are at least at the same levels as other areas around the West Indian Ocean, if not higher. Would they accumulate in the food chain? To some extent they will. They actually become inert in the tissue of some of these fill trading organisms like molluscs, and even in some fish. And they can, because of some of these plastics they have these hormone like effects, so they can affect even the fecundity, like the number of offsprings that these individuals can produce. So that's another more or less indirect effect of pollution that accumulates, and over longer time periods sort of diminishes the productivity and the health of these systems. Let me also ask Mohammed Sheikh specifically what he thinks hotels should do to improve the situation. The first choice is the treatment. They have to treat their wastewater as they have to recycle, and they can use it for gardening and other activities. But if they are going to use septic tanks, they have to make sure that they have concrete septic tanks in order to avoid intrusion of sewage into the marine environment. Untreated sewage into the sea and marine litter seem to be some of the main reasons for the degradation of the marine environment in Zanzibar. By acknowledging that coastal tourism is the dominating sector of the economy, accounting for 27 percent of GDP, one would think it's of high interest to conserve the attractive beaches and clear blue sea. So why has the degradation gone so far, and why is the pressure on coastal areas not managed and regulated? According to a study part of the answer lies in the distribution of the economic benefits from tourism. Much of the tourism industry has excluded local communities and left the population with limited economic incentives to protect the marine environment. Overall it sounds a bit depressing but there might still be hope for sustainable solutions for tourism in Zanzibar. There's a growing understanding among common people, among fishermen, among hotel owners, and also among local sciences, that we really need to do something. Do you have examples of of successes and things that improve the situation at the moment. Yes, we actually do have some very encouraging news from a cooperation we have, from the chimps reef sanctuary, where they have since the 1990s protected areas from overfishing. They have removed threats by invasive species, and they have made sure not to pollute the waters around the island. And it occurs that recovery can be very fast, and it gives me hope that with proper management that we will actually be able to see a fast recovering of many of these beautiful and diverse habitats. An example of how sustainable tourism is being promoted in Zanzibar, is the upgrading of the old Mtoni Marine hotel, two kilometers outside Stone Town. Here, the chairman of the Bakhresa Group states: "we are serious about being the leaders of the green economy sector, and therefore we approach the development of Africa's greenest hotel, The Verde hotels, to ensure that the Verde Hotel Zanzibar will be the greenest Hotel in East Africa. He describes the grey water recycling and waste management systems they're planning to implement. However you can also read that the project is claiming 30 hectares of sea to construct a water park. In other words, the pressure on the coastal environment continues, but in different ways.
