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 sites come from Anderson's survey of 11 March to 3 April 2024, with local partners (Mombasa Marine Park, Tropical Diving Kenya, Whale Shark Adventures, REEFolution, 3 Degrees South, A Rocha, Extra Divers, and PMCC / Northern Rangelands Trust), 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 (no dive depths survive for this survey): 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 13% at Chipopo, a restoration site, to 55% 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% at Sandy Patch and 47% at Brain Coral, both in Mombasa, to 95% at North Canyon and Ocean Trust Nursery. Seven of the nine Kilifi, Watamu, and Pate sites exceeded 80%. Five sites carry a Coral Health Index (scale of zero to five; higher is healthier): Bofa and Round Reef (2.25 each), and Chipopo, Pilot Nursery, and Ocean Trust Nursery (1.00 each).

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. Fleshy macroalgae covered much of the reef at Lower Mpunguti site 1, the Mombasa Marine Park snorkel site, and around the REEFolution nursery.

Crown-of-thorns predation was concentrated at Bofa, where at least nine individuals were found on already-bleached coral, with one or two at Kisite site 4 and one at Kilifi Bay. Turtles, a trumpetfish aggregation, and a Spanish dancer on the Shimoni night dive stand out among the fauna.

Miamba ya Kenya kwa kiasi kikubwa ni miamba ya ufukweni (fringing reefs), aina inayotawala kando ya pwani ya bara ya Afrika Mashariki (Spalding et al. 2001). Kusini mwa Malindi, tambarare nyembamba ya pwani imeegemea majukwaa ya miamba ya Pleistocene yaliyoinuka juu ya jukwaa la sasa la maji kujaa na kupwa, na rafu ya bara inaenea takriban km 5 tu kutoka pwani; kaskazini mwa Malindi inapanuka hadi takriban km 60. Miamba ya ufukweni imekua vizuri zaidi upande wa kusini. Kaskazini zaidi, mashapo yaliyolegea na maji baridi kutoka mito ya Athi-Galana-Sabaki na Tana huzuia ukuaji wa miamba, ingawa miamba ya ufukweni ipo kuzunguka visiwa vya Lamu na kando ya mlolongo wa takriban visiwa 50 vya chokaa karibu na Kiunga. Utofauti pia huwa juu zaidi kusini, na matumbawe yaliyorekodiwa Kenya yanafikia takriban jenasi 55 na hadi spishi 200. Kabla ya 1998, matumbawe hai kwa kawaida yalifunika takriban 30% ya sakafu ngumu, yakichanganyika na vitanda vya nyasi za baharini na mwani. Mwaka 1998, 50–90% ya matumbawe yalionekana kupauka na mengi yakafa, na matumbawe laini yaliathirika zaidi. Hifadhi za kwanza za bahari za Kenya, Malindi na Watamu, zilianzishwa 1968, zikifuatwa na Kisite na Mpunguti mwaka 1978, Mombasa mwaka 1986, na hifadhi ya Diani mwaka 1993, na ulinzi umeleta samaki wengi zaidi, utofauti mkubwa zaidi, na ufunikaji mkubwa zaidi wa matumbawe hai. Spalding et al. (2001) wanakadiria takriban km² 630 za miamba ya matumbawe kwa Kenya, na Souter et al. (2021) wanaweka Bahari ya Hindi Magharibi nzima kuwa takriban km² 15,180, karibu 6% ya jumla ya dunia.

Urejeshaji katika Afrika Mashariki baada ya 1998 ulikuwa mkubwa lakini wa madoa, na bora zaidi kwenye miamba inayosimamiwa vizuri, kwa mujibu wa muhtasari wa Wilkinson (2006) wa ripoti ya hali ya mwaka 2004. Ilitaja idadi inayoongezeka ya watu pwani, pamoja na uchafuzi kutoka nchi kavu na shinikizo linaloongezeka la uvuvi, kama tishio kubwa zaidi, na ikaorodhesha Kenya pamoja na Tanzania na Great Barrier Reef kama maeneo yenye msongamano wa juu zaidi wa hivi karibuni wa samaki nyota taji la miiba. Souter et al. (2021) wanatambua 1998 na 2016 kama matukio mawili ya upaukaji yaliyoenea katika eneo zima la Bahari ya Hindi Magharibi, pamoja na matukio madogo mwaka 2005, 2007, na 2010 yaliyoingiliana na uvuvi na mikazo ya kienyeji. Baada ya tukio la 2016, uchunguzi wa sayansi ya wananchi uligundua kwamba eneo moja kati ya matano lilipoteza zaidi ya nusu ya matumbawe yake. Tafiti nyingine zilizochapishwa zilizotajwa katika ripoti hiyo zinaonyesha vifo vya 45–70% mwaka 1998, na baada ya hapo ufunikaji haukurudi tena kwenye kiwango chake cha awali.

Maeneo 21 ya Kenya yanatokana na uchunguzi wa Anderson wa tarehe 11 Machi hadi 3 Aprili 2024, pamoja na washirika wa ndani (Mombasa Marine Park, Tropical Diving Kenya, Whale Shark Adventures, REEFolution, 3 Degrees South, A Rocha, Extra Divers, na PMCC / Northern Rangelands Trust), wakati wa tukio la upaukaji mkubwa la Bahari ya Hindi Magharibi. Yanaanzia Hifadhi ya Bahari ya Mombasa kusini kupitia Diani na mlangobahari wa Shimoni-Wasini hadi Kisite-Mpunguti, na kaskazini kupitia Kilifi na Watamu hadi Kisiwa cha Pate katika visiwa vya Lamu. Yote ni ya kina kifupi (hakuna kina cha mizamio kilichobaki kwa uchunguzi huu): tambarare za miamba ya ufukweni, matuta ya sakafu ngumu, viwanja vya bommie, na maeneo manne ya urejeshaji (kitalu cha REEFolution huko Shimoni na vitalu vitatu huko Pate). Jamii inayojenga mwamba hubadilika kando ya pwani. Matumbawe bapa ya majani na tabaka ya aina ya Turbinaria, Montipora, na Echinopora yanatawala Sandy Patch na Diani, bommie kubwa za Porites katika eneo la snorkel la Hifadhi ya Bahari ya Mombasa, Acropora ya meza Dolphin Point, na mazulia ya Galaxea yenye vifundo yanafunika Coral Garden na Kisite site 4.

Ufunikaji uliochapishwa wa matumbawe magumu katika maeneo 20 yaliyopimwa ulianzia 13% Chipopo, eneo la urejeshaji, hadi 55% Coral Garden huko Kisite, ambako matumbawe yamejaa kila mahali katika maji ya bluu safi. Sehemu ya tishu za matumbawe magumu iliyopauka ilianzia 45% Sandy Patch na 47% Brain Coral, yote mawili Mombasa, hadi 95% North Canyon na Ocean Trust Nursery. Maeneo saba kati ya tisa ya Kilifi, Watamu, na Pate yalizidi 80%. Maeneo matano yana Coral Health Index (kipimo cha sifuri hadi tano; kadiri thamani inavyokuwa juu, ndivyo afya ilivyo bora): Bofa na Round Reef (2.25 kila moja), na Chipopo, Pilot Nursery, na Ocean Trust Nursery (1.00 kila moja).

Hakuna umbo moja la ukuaji lililonusurika kwa uthabiti. Outer Kisite, vichaka vya Acropora ya matawi vilibeba madhara huku vilima vya Porites kubwa na matuta ya matumbawe bapa yakishikilia rangi. Bofa, Round Reef, na Uyombo, matumbawe makubwa na ya ubongo yalikuwa miongoni mwa yaliyopauka kabisa zaidi, na matumbawe bapa ya Turbinaria ndio walionusurika Bofa, Kilifi Bay, na Lower Mpunguti site 1. Zulia la Galaxea lilishikilia rangi yake Coral Garden lakini likawa jeupe kama uwanja wa theluji Kisite site 4. Rangi za mkazo za waridi, zambarau hafifu, urujuani, na kijani-manjano zilijirudia Uyombo, North Canyon, na Kilifi Bay. Akiba ya urejeshaji ilikuwa mchanganyiko, vipande vyenye rangi na vyeupe vikiwa kando kwa kando kwenye miundo ile ile. Mwani mkubwa wenye nyama ulifunika sehemu kubwa ya mwamba Lower Mpunguti site 1, eneo la snorkel la Hifadhi ya Bahari ya Mombasa, na kuzunguka kitalu cha REEFolution.

Uwindaji wa samaki nyota taji la miiba ulijikita Bofa, ambako angalau wanyama tisa walikutwa juu ya matumbawe ambayo tayari yamepauka, huku mmoja au wawili wakionekana Kisite site 4 na mmoja Kilifi Bay. Kasa, mkusanyiko wa samaki trumpetfish, na Spanish dancer katika mzamio wa usiku wa Shimoni vinajitokeza miongoni mwa viumbe.