Krabi mangrove kayaking: roots, tides and the creeks to paddle

Krabi mangrove kayaking makes more sense once you know what you are paddling through. Mangroves are salt-tolerant trees and shrubs that grow in the intertidal zone, the strip between land and sea, along tropical and subtropical coasts, in lagoons, estuaries, rivers and deltas.⁶ There are about 80 species of mangrove tree, and they only grow in warm latitudes because none of them can withstand freezing temperatures.^1,2 The forests are not one species of tree but a family of related answers to the same problem: how to stand in salty mud.

That mud is the clue to the whole ecosystem. The trees take root where the soil holds little oxygen and slow-moving water lets fine sediment settle.⁷ Their roots do the engineering. Many mangrove forests are recognised by a dense tangle of prop roots that lift the trunks on stilts above the water, and the same roots slow the tidal flow so that more sediment drops out and the muddy bottom builds up.^8,9 When your kayak glides past a wall of arching roots, you are looking at a machine that makes land.

The United Nations Food and Agriculture Organization estimates that mangroves cover about 14.8 million hectares worldwide, and rates mangrove forests among the ecosystems most at risk anywhere on Earth.^10,11 That is worth holding in mind on the water. A guided paddle through a healthy creek is a rare chance to see the thing up close, and the better you understand it, the lighter you will tread.

Krabi is a natural home for mangrove paddling. The Tourism Authority of Thailand paints the province as limestone cliffs, turquoise sea and mangrove channels beside small fishing villages.¹⁸ Among its Krabi activities, the Authority lists paddling through the Ao Thalane mangroves.¹⁹ The bay sits north of the beach town of Ao Nang on the mainland, and the half-day listing offers pickup from Ao Nang, Krabi town and Klong Muang.

A well-documented stretch of Krabi mangrove is the Krabi Estuary, a Ramsar wetland listed on 5 July 2001 that covers 21,299 hectares.²⁰ The Ramsar record describes sand beach, mangroves and mudflats, with intertidal flats reaching up to 2km offshore at low tide, and counts 221 bird species in the mangrove areas.^4,21 It also notes that water quality had suffered from nearby community growth and the rapid rise of tourism around Krabi city, a reminder that this forest sits right next to a busy place.²²

Inland from the sea, Than Bok Khorani National Park protects further mangrove swamp forest in the muddy soil along the shore and the estuaries of large rivers, including at Ao Nam, Laem Sak and Ba Kan Canal.²³ A Thai forestry survey that used satellite images from 1973 found about 80% of the country's mangroves on the Andaman coastline, with Phang Nga province holding the largest single area.^24,25 That count is old, so treat it as a sense of the pattern rather than today's map.

A mangrove is a nursery. The Food and Agriculture Organization describes mangroves as homes, breeding sites and nurseries for fish, crustaceans and molluscs, and says the leaf litter they shed feeds crabs, clams, oysters and other shellfish as well as bony fish.^31,32 The United States' ocean agency adds that the tangled roots draw fish and other small creatures looking for a meal or a place to hide.¹⁷ Under your kayak, in other words, there is more going on than you can see.

Above the waterline it is the birds and monkeys that give the paddle its character, and the Ao Thalane listings are specific about who to look out for. The estuary's bird tally in the Ramsar record, mentioned earlier, hints at how busy the canopy can be.²¹ The page on caves and wildlife goes deeper into who lives here.

Remember that a sighting is never promised. The wildlife keeps its own timetable and the tide moves it around. Be still, keep your paddle quiet when a bird is close, and let the guide do the pointing. The forest also does a job for people: mangroves stabilise the coastline and reduce erosion from storm surges, currents, waves and tides.³³ A calm creek is a working piece of coastal defence as well as a pretty place.