Mangrove Tours in Zanzibar and the Rufiji Delta

What a mangrove tour here actually is

Mangrove forest is the least photogenic and most consequential habitat on the Tanzanian coast. It is a tidal forest of salt-tolerant trees growing in mud between the land and the sea, flooded twice a day, and it is where a very large proportion of everything else on this coast begins life.

Visiting one takes two forms. There is the boardwalk, a raised walkway through the forest that lets you look at it at eye level, at any tide, without sinking into anything. And there is the creek, where a small boat or a kayak follows the tidal channels into the forest at high water. The two give completely different impressions of the same habitat and it is worth doing both if the trip allows.

This coast sits beside Tanzania's safari country rather than inside it. A mangrove morning belongs to a coastal week, though on the Rufiji it sits directly alongside the southern safari circuit.

How to read a mangrove forest

A mangrove forest looks undifferentiated until you know what the roots are doing, at which point it separates into bands.

The trees nearest the open water, standing in the deepest and longest-flooded mud, are the ones on tall arching stilt roots that hold the trunk clear of the water. Those are the red mangroves, and they are the image most people carry of the habitat.

Behind them, on ground that drains between tides, are trees with thousands of thin vertical pegs pushing up out of the mud around them. Those pegs are breathing roots: mangrove mud has effectively no oxygen in it, so the tree grows snorkels. Walking past a stand of them at low water, with crabs moving between the spikes, is the part of a mangrove visit people remember.

Further back again, on ground flooded only by the highest tides, the trees look more ordinary and the forest begins to resemble dry land. Between those bands sit species with knee-shaped roots, with buttresses, and with fruit like green apples or cannonballs.

That banding is not decoration. It is a map of how long each patch of ground spends under salt water, and once you can see it you can read the tide off the forest.

The Pete and Jozani boardwalk

The best-known mangrove visit in Tanzania is the boardwalk at the southern edge of Jozani-Chwaka Bay National Park on Unguja, crossing the tidal inlet between the villages of Pete and Jozani.

Jozani-Chwaka Bay was first gazetted as a forest reserve in 1960 and became a national park, Zanzibar's only one, on the twenty-seventh of February 2004, covering roughly fifty square kilometres. It was established primarily to protect the Zanzibar red colobus, the endemic monkey found nowhere else, and most visitors come for that. The mangrove boardwalk is the second half of the same visit and is frequently rushed.

The walkway runs out over the mud and the channel on a raised timber structure, which means the forest is accessible at any state of the tide and without wading. At high water you are walking over sea. At low water you are walking over exposed mud full of crabs, and that is the better visit for anybody interested in what lives there.

It is short, it is flat, it suits all ages and mobility levels, and it is a fifteen-minute-to-an-hour experience rather than a morning. It combines naturally with the colobus forest, with the coral rag forest trail in the same park, and with the east coast beaches, which are twenty minutes away.

The Rufiji delta

The Rufiji delta, where Tanzania's largest river reaches the sea opposite Mafia, holds East Africa's largest mangrove forest. Wetlands International puts it at roughly 53,255 hectares.

The numbers attached to it explain why it matters far beyond its own boundaries. The delta's mangroves support at least 437 bird species. They underpin something in the order of eighty percent of Tanzania's annual prawn harvest, because the creeks are the nursery. And the delta is the country's principal blue carbon store, which is to say the single most important place in Tanzania for carbon held in coastal sediment.

Visiting it is a different proposition from the boardwalk. This is boat country, reached from the Nyerere National Park side upriver, from the delta villages, or across from Mafia. Channels are wide, the forest is enormous, and the wildlife includes crocodiles and hippos in the upper reaches. It is the version of a mangrove visit that feels like an expedition rather than an excursion, and it needs a boat and a guide who know the channels, because a delta at low water is a maze of mud.

Where else mangroves are visited

Chwaka Bay, on the east side of Unguja, has extensive mangrove and is visited by boat from the bay villages. Menai Bay in the south-west has mangrove creeks that are often combined with a sandbank trip.

On the mainland, the Wami river mouth inside Saadani National Park is the easiest mangrove boat trip to combine with a safari, and it is the place where hippos, crocodiles, mangrove and beach are within a few kilometres of each other. Pangani has the river and its creeks. The Tanga coast and Kilwa both have mangrove systems alongside their historical sites, and at Kilwa the boat to the ruined city passes through them.

In the far south, the Mnazi Bay–Ruvuma Estuary Marine Park protects mangrove at the river mouth, and on Pemba the creeks and inlets around the island's indented western coast hold substantial forest.

The tide decides the trip

This is the practical point that almost nothing published about mangrove tours mentions.

A mangrove creek is only navigable on enough water. At low tide, channels that a boat glided along two hours earlier are mud. So boat-based mangrove trips run on the tide, and on this coast, where the range runs from roughly a metre at the neaps to over three metres at the springs, that is a hard constraint rather than a preference. Departure times move by about fifty minutes each day.

The two states give genuinely different visits. High water gets you in among the trees, floating level with the canopy of the low stuff, and is the quiet, atmospheric version. Low water exposes the mud, the roots and everything living on them, and is the version where you actually see animals.

A boardwalk sidesteps the problem entirely, which is a large part of its value.

What lives in there

Crabs first, because there are thousands of them. Fiddler crabs wave a single outsized claw across the exposed mud at low water in numbers that take a moment to register. Mudskippers, fish that spend a good deal of their time out of water, skip and prop themselves up on the surface.

Birds are the other reason to come. Mangrove kingfishers and other kingfishers, herons and egrets, sandpipers and waders on the exposed mud, fish eagles, and on the Rufiji a bird list running to hundreds of species. Dawn is the time.

Beyond that: monkeys working the forest edge, including the Zanzibar red colobus and Sykes' monkeys at Jozani; bats, with Pemba's flying fox colonies the standout on that island; monitor lizards; and in the delta and river systems, crocodiles and hippos, which is a real consideration for how close to the water you get.

Underwater, and out of sight, the creeks are a nursery for juvenile fish and prawns, which is the ecological function that makes mangrove loss a fisheries problem rather than only a forestry one.

Why the forest is under pressure

Mangroves in Tanzania are protected and cutting is regulated, and they are still being lost.

Wetlands International records roughly 7,004 hectares of Rufiji delta mangrove cleared for rice farming between 1991 and 2015, an average of about 292 hectares a year. Elsewhere the pressures are cutting for poles and firewood, charcoal, salt pans, aquaculture and coastal development, along with upstream changes to river flow and sediment.

Restoration is happening and it is harder than planting seedlings. Replanting without matching the species to the right tidal band, or without dealing with the reason the forest was cleared in the first place, produces the photographs rather than the forest.

The reason to say any of this in a visitor guide is that mangrove tourism is one of the few ways the forest generates income while standing up. A village-run boardwalk or boat trip gives a community a reason to keep a forest that would otherwise be worth more as poles, and that argument is more persuasive when visitors understand what they are looking at.

Practicalities

Mosquitoes are the main discomfort, particularly at dawn and dusk, which is also when the birds are active. Long sleeves, long trousers and repellent, and the malaria precautions you should be taking on this coast anyway.

Footwear for mud if you are going anywhere other than a boardwalk, and be prepared for it to be ruined. Sun protection, because a boat in a creek gets more sun than the shade suggests. Binoculars, which transform the bird half of the trip. A dry bag.

Go early. The forest is quieter, cooler, fuller of birds and far more pleasant before the middle of the day, and on a boardwalk you avoid the arrival of the tour groups.

Several mangrove sites sit inside national parks, marine parks or conservation areas with fees payable to the managing authority. Those fees change and are not quoted here, which is why the national park and Ngorongoro tariffs are kept in one place, dated and sourced rather than scattered through the guides. Ask what is payable and to whom. The sea kayaking guide covers paddling the creeks, which is the quietest way in, and the bird watching guide covers the species in more detail.

Common questions about mangrove tours in Tanzania