Kenya

Kenya's reefs are mostly fringing reefs, the predominant type along mainland East Africa (Spalding et al. 2001). South of Malindi, a narrow coastal plain is backed by raised Pleistocene reef platforms standing above today's intertidal platform, and the continental shelf extends only about 5 km offshore; north of Malindi it widens to about 60 km. Fringing reefs are best developed in the south. Farther north, loose sediment and fresh water from the Athi-Galana-Sabaki and Tana rivers hold back reef growth, although fringing reefs occur around the Lamu islands and along a chain of about 50 calcareous barrier islands near Kiunga. Diversity also tends to be higher in the south, and Kenya's recorded coral fauna runs to about 55 genera and as many as 200 species. Before 1998, live coral typically covered about 30% of hard substrate, interspersed with seagrass and algal beds. In 1998, 50–90% of corals appeared to bleach and many died, and soft corals fared even worse. Kenya's first marine parks, at Malindi and Watamu, date from 1968, followed by Kisite and Mpunguti in 1978, Mombasa in 1986, and the Diani reserve in 1993, and protection has brought more fish, greater diversity, and higher live coral cover. Spalding et al. (2001) estimate about 630 km² of coral reef for Kenya, and Souter et al. (2021) put the whole Western Indian Ocean at about 15,180 km², nearly 6% of the world total.

Recovery in East Africa after 1998 was significant but patchy, and better on well-managed reefs, according to Wilkinson's (2006) summary of the 2004 status report. It named the growing coastal population, with land-based pollution and rising fishing pressure, as the largest threat, and listed Kenya with Tanzania and the Great Barrier Reef as the places with the highest recent densities of crown-of-thorns starfish. Souter et al. (2021) identify 1998 and 2016 as the two region-wide bleaching events in the Western Indian Ocean, with smaller episodes in 2005, 2007, and 2010 that interacted with fishing and local stressors. After the 2016 event, citizen-science surveys found that one site in five had lost more than half of its corals. Other published studies cited in that report point to 1998 mortality of 45–70%, after which cover never climbed back to its earlier level.

The 21 Kenya pins come from Anderson's survey of 11 March to 3 April 2024, during the Western Indian Ocean mass bleaching event. They run from Mombasa Marine Park south through Diani and the Shimoni-Wasini channel to Kisite-Mpunguti, and north through Kilifi and Watamu to Pate Island in the Lamu archipelago. All are shallow, from 0.5 m at Lower Mpunguti site 2 to 15 m at North Canyon: fringing reef flats, hardground terraces, bommie fields, and four restoration sites (the REEFolution nursery at Shimoni and three nurseries on Pate). The reef-building community changes along the coast. Foliose and laminar plates of Turbinaria, Montipora, and Echinopora type dominate at Sandy Patch and Diani, massive Porites bommies at the Mombasa Marine Park snorkel site, tabulate Acropora at Dolphin Point, and knobby Galaxea carpets cover Coral Garden and Kisite site 4.

Published hard coral cover at the 20 scored sites ranged from 12.8% at Chipopo, a restoration site, to 55.0% at Coral Garden in Kisite, which is wall-to-wall coral in clear blue water. The share of hard coral tissue bleached ranged from 45.4% at Sandy Patch and 46.6% at Brain Coral, both in Mombasa, to 95.3% at North Canyon and 95.4% at Ocean Trust Nursery. Six of the nine Kilifi, Watamu, and Pate sites exceeded 80%. Bofa carries the unit's only Coral Health Index, 2.25, just below the 2.5 average.

No single growth form was consistently spared. At Outer Kisite the branching Acropora thickets took the damage while massive Porites hillsides and plate terraces held pigment. At Bofa, Round Reef, and Uyombo the massive and brain corals were among the most completely bleached, and Turbinaria plates were the survivors at Bofa, Kilifi Bay, and Lower Mpunguti site 1. The Galaxea carpet held its color at Coral Garden but went white as a snowfield at Kisite site 4. Pink, mauve, violet, and chartreuse stress coloration recurred at Uyombo, North Canyon, and Kilifi Bay. Restoration stock was mixed, with pigmented and white fragments side by side on the same structures.

Crown-of-thorns predation was concentrated at Bofa, where at least nine individuals were found on already-bleached coral, with single or paired sightings at three other sites. Turtles, a trumpetfish aggregation, and a Spanish dancer on the Shimoni night dive stand out among the fauna.

Miamba ya matumbawe ya Kenya kwa kiasi kikubwa ni miamba ya pwani (fringing reefs), aina inayotawala kando ya pwani ya bara la Afrika Mashariki (Spalding et al. 2001). Kusini mwa Malindi, uwanda mwembamba wa pwani una nyuma yake majukwaa ya miamba ya enzi ya Pleistocene yaliyoinuka juu ya jukwaa la sasa la eneo la maji kujaa na kupwa, na rafu ya bara inaenea takriban 5 km tu kutoka pwani; kaskazini mwa Malindi inapanuka hadi takriban 60 km. Miamba ya pwani imestawi zaidi upande wa kusini. Kaskazini zaidi, mashapo yaliyolegea na maji yasiyo ya chumvi kutoka mito ya Athi-Galana-Sabaki na Tana huzuia ukuaji wa miamba, ingawa miamba ya pwani ipo kuzunguka visiwa vya Lamu na kando ya mnyororo wa takriban visiwa 50 vya kizuizi vya chokaa karibu na Kiunga. Bioanuwai pia huwa kubwa zaidi upande wa kusini, na matumbawe yaliyorekodiwa nchini Kenya yanafikia takriban jenasi 55 na hadi spishi 200. Kabla ya 1998, matumbawe hai kwa kawaida yalifunika takriban 30% ya sakafu ngumu, yakichanganyika na maeneo ya nyasi bahari na mwani. Mwaka 1998, 50–90% ya matumbawe yalionekana kupauka na mengi yalikufa, na matumbawe laini (soft corals) yaliathirika hata zaidi. Hifadhi za kwanza za bahari za Kenya, huko Malindi na Watamu, zilianzishwa mwaka 1968, zikifuatiwa na Kisite na Mpunguti mwaka 1978, Mombasa mwaka 1986, na hifadhi ya Diani mwaka 1993, na ulinzi umeleta samaki wengi zaidi, bioanuwai kubwa zaidi, na kiwango cha juu zaidi cha matumbawe hai. Spalding et al. (2001) wanakadiria takriban 630 km² za miamba ya matumbawe kwa Kenya, na Souter et al. (2021) wanakadiria eneo lote la Bahari ya Hindi Magharibi (Western Indian Ocean) kuwa takriban 15,180 km², karibu 6% ya jumla ya dunia.

Kwa mujibu wa muhtasari wa Wilkinson (2006) wa ripoti ya hali ya miamba ya mwaka 2004, urejeaji wa matumbawe Afrika Mashariki baada ya 1998 ulikuwa mkubwa lakini haukuwa sawa kila mahali, na ulikuwa bora zaidi kwenye miamba iliyosimamiwa vizuri. Ripoti hiyo ilitaja ongezeko la idadi ya watu wa pwani, pamoja na uchafuzi kutoka nchi kavu na shinikizo linaloongezeka la uvuvi, kuwa tishio kubwa zaidi, na iliorodhesha Kenya pamoja na Tanzania na Great Barrier Reef kama maeneo yenye msongamano mkubwa zaidi wa hivi karibuni wa nyota wa bahari aina ya crown-of-thorns. Souter et al. (2021) wanatambua 1998 na 2016 kuwa matukio mawili ya kupauka kwa matumbawe yaliyoenea kanda nzima ya Bahari ya Hindi Magharibi, pamoja na matukio madogo mwaka 2005, 2007, na 2010 yaliyoingiliana na uvuvi na mikazo mingine ya kienyeji. Baada ya tukio la 2016, tafiti za sayansi ya wananchi (citizen science) ziligundua kwamba eneo moja kati ya matano lilikuwa limepoteza zaidi ya nusu ya matumbawe yake. Tafiti nyingine zilizochapishwa zinazonukuliwa katika ripoti hiyo zinaonyesha vifo vya 45–70% mwaka 1998, na baada ya hapo kiwango cha matumbawe hakikurudi tena katika kiwango chake cha awali.

Pini 21 za Kenya zinatokana na utafiti wa Anderson wa Machi-Aprili 2024 wakati wa tukio la kupauka kwa matumbawe kwa wingi (mass bleaching) katika Bahari ya Hindi Magharibi. Zinaanzia Mombasa Marine Park kuelekea kusini kupitia Diani na mfereji wa Shimoni-Wasini hadi Kisite-Mpunguti, na kaskazini kupitia Kilifi na Watamu hadi Kisiwa cha Pate (Pate Island) katika funguvisiwa la Lamu. Nyingi ni za kina kifupi, kati ya 0.5 m na 15 m: tambarare za miamba ya pwani, matuta ya sakafu ngumu, maeneo ya bommie (vichuguu vya matumbawe), na maeneo manne ya urejeshaji (kitalu cha REEFolution huko Shimoni na vitalu vitatu huko Pate). Jamii ya matumbawe yanayojenga miamba hubadilika kando ya pwani. Mabamba yenye umbo la majani na tabaka ya aina ya Turbinaria, Montipora, na Echinopora yanatawala Sandy Patch na Diani, bommie kubwa za Porites zinatawala eneo la snorkel la Mombasa Marine Park, Acropora yenye umbo la meza inatawala Dolphin Point, na mazulia ya Galaxea yenye vifundo yanafunika Coral Garden na Kisite site 4.

Kiwango cha matumbawe magumu kilichochapishwa kilianzia 12.8% huko Chipopo, eneo la urejeshaji, hadi 55.0% katika Coral Garden huko Kisite, ambayo imejaa matumbawe kila upande katika maji safi ya buluu. Sehemu ya tishu za matumbawe magumu iliyopauka ilianzia 45.4% huko Sandy Patch na 46.6% huko Brain Coral, zote mbili Mombasa, hadi 95.3% huko North Canyon na 95.4% huko Ocean Trust Nursery. Maeneo mengi ya Kilifi, Watamu, na Pate yalizidi 80%.

Hakuna umbo moja la ukuaji lililonusurika kila mara. Huko Outer Kisite, vichaka vya Acropora vyenye matawi ndivyo vilivyopata madhara, huku miteremko ya Porites mikubwa na matuta ya mabamba yakibaki na rangi. Huko Bofa, Round Reef, na Uyombo, matumbawe makubwa (massive) na matumbawe ya ubongo (brain corals) yalikuwa miongoni mwa yaliyopauka kabisa zaidi, na mabamba ya Turbinaria ndiyo yaliyonusurika huko Bofa, Kilifi Bay, na Lower Mpunguti site 1. Zulia la Galaxea lilidumisha rangi yake katika Coral Garden lakini likawa jeupe kama uwanja wa theluji huko Kisite site 4. Rangi za msongo za waridi, zambarau hafifu, urujuani, na kijani-manjano zilijitokeza tena na tena huko Uyombo, North Canyon, na Kilifi Bay. Hali ya matumbawe ya urejeshaji ilikuwa mchanganyiko, vipande vyenye rangi na vyeupe vikiwa kando kwa kando kwenye miundo ile ile.

Uwindaji wa nyota wa bahari aina ya crown-of-thorns ulijikita huko Bofa, ambako angalau nyota tisa walipatikana juu ya matumbawe yaliyokwisha kupauka, na walionekana mmoja mmoja au wawili wawili katika maeneo mengine matatu. Kasa, kundi la samaki trumpetfish, na Spanish dancer (koa wa bahari) katika uzamiaji wa usiku huko Shimoni wanajitokeza miongoni mwa wanyama.