CORDIO Status Report 2002.pdf

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Coral Reef Degradation in Tanzania: Results of Monitoring 1999–2002 MOHAMMED S. MOHAMMED 1 , CHRISTOPHER MUHANDO 1 & HAJI MACHANO 2 1 <strong>CORDIO</strong> East Africa, Institute of Marine Sciences, Zanzibar, Tanzania 2 Department of Environment, Zanzibar Key words: coral bleaching, coral degradatio, coral recruitment, El Niño, Tanzania, western Indian Ocean INTRODUCTION Coral reefs play a crucial role in the well-being of coastal communities in Tanzania (Muhando, 1999; Johnstone et al., 1998). Despite their usefulness, coral reefs are being degraded by destructive anthropogenic activities (Salm et al., 1998) and natural causes (e.g., coral competition, predation, diseases, bleaching, etc.). The 1998 coral bleaching and mortality event was the most serious natural calamity ever recorded in the Indian Ocean (Wilkinson et al., 1999). Several areas along the coast of Tanzania were affected. Highest coral mortality was recorded in Tutia reef in Mafia Island Marine Park and on Misali reef on the west coast of Pemba. Coral mortality was low on reefs around Unguja Island, Zanzibar (Muhando, 1999). After the bleaching and coral mortality event (in March–June 1998), the status of Tanzania reefs became unclear and it was apparent that there was a need to assess and monitor the extent of coral mortality, and its effects on reef ecosystems and the socio-economy of coastal populations (fisheries and tourism). Three teams of researchers were formed. The first dealt with the assessment and monitoring of coral reefs, the second dealt with socio-economic effects and the third team investigated specific issues relevant to coral bleaching, mortality and recovery. The specific objectives of the coral reef assessment and monitoring team in Tanzania were as follows: ● ● ● ● ● To assess and monitor the benthic cover on coral reefs on selected sites on Tanzania mainland and the Islands. To assess and monitor the distribution and density of ecologically important macrobenthos. To assess and monitor the reef fish distribution and composition. To measure some of the environmental parameters at the study sites. To assess the distribution and density of coral recruits (new objective added in the last monitoring). This presentation is an attempt to summarise reef assessment and monitoring results for the years 1999–2002. MATERIALS AND METHODS Study Sites Coral reef assessment and monitoring were carried out around Unguja (Zanzibar) Island reefs (Chapwani, Changuu, Bawe, Chumbe and Kwale), and on Misali reefs (West of Pemba Island). The geographic positions (in UTM units), exposure to waves (protected or semiexposed) and tidal current strength (strong, medium, weak), the number of random and permanent transects are given in Table 1 (next page). 21
Table 1. The geographic positions (in UTM units), exposure to waves (protected or exposed) and tidal current strength (strong (S), medium (M), weak (W), the number of random (RT) and permanent transects (PT) at each study site Station Position Exposure Currents Length of each No. of (UTM) point transect (m) point transect (m) Chapwani 521205 Protected W 50 6 9323362 Changuu 518524 Protected W 50 4 9324192 Bawe 514784 Protected W 50 9 9321110 Chumbe 519205 Protected W 50 9 9306420 Kwale 531327 Protected M 50 6 9294468 Misali* 566038 Semi-exp. M 20 8 9421475 Tutia 571445 Semi-exp S 50 20 9102894 Utumbi 586768 Protected S 50 13 9121552 Msumbiji 587441 Protected S 50 8 9120090 *permanent line intercept transects were used Measurement of Coral Reef Benthic Cover Benthic reef cover was estimated using permanent Line- Intercept Transect (LIT) method (English et al., 1994) in Misali Island and random Line-Point Transect (LPT) (Allison, 1996) in Zanzibar reefs. Random transects were placed on the study site and benthic categories were recorded. A total of 200 points were recorded on each 50 m random transect. The interval between points was 25 cm. A plumb-line was used to reduce observer parallax errors (Allison, 1996). At all sites, transects were set on the reef flat (1–5 m) and reef slope (5–15 m) parallel to the reef front. The benthic categories on the reef were then categorised into seven groups; live hard corals, soft corals, coralline algae, fleshy algae (including filamentous algae), sponges, dead coral, substrate (rubble, sand, rock and silt) and others (Rhodactis, zoanthid, clam, seagrass and others). Live corals were recorded according to their life-forms (as in English et al., 1994). Reef Macrobenthos (macro-invertebrates) Reef animals that are relatively easy to see and could indicate the health of the coral reef were counted in belt transects 50 m long and 2 m wide set randomly on the reef. A T-stick was used to maintain the belt width. The macrobenthos counted included crown-of-thorns starfish (Acanthaster planci – COTS), sea cucumbers (Holothuroidea), sea urchins (Echinoidea), sea stars 22
Page 1 and 2: Coral Reef Degradation in the India
Page 3 and 4: Coral Reef Degradation in the India
Page 5 and 6: Contents Foreword 7 Executive Summa
Page 7 and 8: Foreword In addition to being magni
Page 9 and 10: Executive Summary Since the 1998 co
Page 11 and 12: REEFS OF THE GULF OF MANNAR AND NIC
Page 13 and 14: Part I East Africa 13
Page 15 and 16: MORTALITY AND RECOVER AFTER THE 199
Page 17 and 18: Table 2. Area and date for reportin
Page 19: Obura, D., Suleiman, M., Motta, H.,
Page 23 and 24: changes are minor and show slight i
Page 25 and 26: mean number/m 2 mean number/m 2 10
Page 27 and 28: % 90 80 70 60 50 40 30 20 10 0 Tuti
Page 29 and 30: In Misali there are very few reprod
Page 31 and 32: observed to induce a shift in the c
Page 33 and 34: 20 Corallimorpharian cover (%) 15 1
Page 35 and 36: Table 2. Proportions of corallimorp
Page 37 and 38: corallimorpharians in terms of bent
Page 39 and 40: Seawater Temperature on Shallow Ree
Page 41 and 42: ing Southeast (SE) monsoon (May-Oct
Page 43 and 44: 31 Coral settlement density Seawate
Page 45 and 46: Jokiel, P. L., & Guinther, E. B., (
Page 47 and 48: 50 40 Southern coast Parks Fished C
Page 49 and 50: 30 Sites Quadrats/site 8 Adults/m 2
Page 51 and 52: Latitude (degrees) -1.7 -1.8 -1.9 -
Page 53 and 54: Obura, , D. O., Uku, J. N., Wawiye,
Page 55 and 56: people live within Mozambique’s 4
Page 57 and 58: Percentage cover 60 50 40 30 20 10
Page 59 and 60: Pereira, M. A. M., Gonçalves, P. M
Page 61 and 62: later converted into percentage cov
Page 63 and 64: Table 2. The substrate cover of the
Page 65 and 66: Percentage cover 100 90 80 70 60 50
Page 67 and 68: a) Filamentous algae Hypnea sp. Fil
Page 69 and 70: Participatory Monitoring of an Arti
Page 71 and 72:
for management purposes and scienti
Page 73 and 74:
ever, suffer from the presence of t
Page 75 and 76:
Traps 100 y z Gill nets Handlines H
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250 m 2 at highly fished sites (sim
Page 79 and 80:
Table 6. Interpretation of correlat
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The success of any management inter
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BACKGROUND Kleypas et al. (1999) as
Page 85 and 86:
50 y = -0.5989x + 45.87 R 2 = 0.495
Page 87 and 88:
Table 4. Species Reproductive strat
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Schleyer, M. H., Obura, D., Motta,
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Coral Reef Degradation in South Asi
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al.; 1999, Wilkinson et al., 1999).
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tance of reef fisheries in India, s
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working group is preparing specific
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scientific data and results can be
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The Conservation Status of Coral Re
Page 103 and 104:
Table 1. Study sites in Andaman and
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K (Competitors) 10 90 20 80 30 70 4
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phologies in each of the three adap
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Table 4. Mortality index, relative
Page 111 and 112:
Sheppard, C. R. C., (1988) ‘Simil
Page 113 and 114:
Figure 1. Fixing of coral fragments
Page 115 and 116:
Table 1. List of species of hard co
Page 117 and 118:
Status of the Coral Reefs of Maldiv
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Table 2. Reef Check data showing 19
Page 121 and 122:
Figure 5. Large colonies of Acropor
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Spatial and Temporal Patterns of Co
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Figure 2. The three sites in Vaavu
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No coral spat/plate (0.04 m≤) No
Page 129 and 130:
Percent cover 100% 80% 60% 40% 20%
Page 131 and 132:
frequency (no/m≤) 20 15 10 5 0 Fe
Page 133 and 134:
Assessing Bioerosion and Its Effect
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16 weight removed by bioerosion (%)
Page 137 and 138:
Status Report on the Condition of R
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During the immediate post-bleaching
Page 141 and 142:
spp.), caught on the coral reefs in
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Figure 7. Recolonisation by Acropor
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activities. Such problems are the m
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Reef Fisheries and Coral Reef Degra
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southern Sri Lanka. Before 1998 the
Page 151 and 152:
Table 3. Spiny lobster catches in W
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No. of fishermen 12 8 4 0 Negombo W
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Gerald, R., Allen, R., Steene, C.,
Page 157 and 158:
THE ORNAMENTAL FISH COLLECTION AND
Page 159 and 160:
positive correlations between fish
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of September, and packing lists fro
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REFERENCES Andrews, C., (1990) ‘T
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Future Effects of Climate Change on
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which operated on multi-decadal tim
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elevation in Maldives is only 5 m,
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The predicted warming will produce
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IPCC (1997) The Regional Impacts of
Page 175 and 176:
2001 Bleaching on Acropora Dominate
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Daily mean SST anomaly (°C) 1.5 1.
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nb of cells per g of biodetritus 30
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Status of Coral Reefs at Réunion,
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Geyser bank, located between Mayott
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was now observed (25%) for stations
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pacted large areas of coral reef in
Page 189 and 190:
Table 1. Study Sites Location of th
Page 191 and 192:
ABUNDANCE OF DIADEMA SETOSUM The de
Page 193 and 194:
Table 5. Total number of genera obs
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Table 9. Summary of indicator fish
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ACKNOWLEDGMENTS We are very gratefu
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Chagos Archipelago Peros Banhos Sal
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30.0 29.5 29.0 28.5 deg C 28.0 27.5
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uild-up of beaches. However, at som
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Figure 9. Eroded rim of the island
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Sheppard, C. R. C., (1999b) ‘Cora
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Table 1. Overview of the 40 coral r
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Transects were placed at an oblique
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RESULTS Scleractinian Live Hard Cor
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Mean % live hard coral cover 10 5 0
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partly confounded due to the signif
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Table 6a. (continued) Type Site No.
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Table 6a. (continued) Type Site No.
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Figure 15. Recent Acropora sp. recr
Page 225 and 226:
sampled was calculated at 9.4 + 0.4
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Harriott, V. J., & Fisk, D. A., (19
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growth, and to recover reef habitat
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The quantified fish surveys on the
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cussed on obtaining a video record
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arely exposed at low tide, and are
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50 Outer reef families 40 Percent 3
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7241 86 14 0 950 24 72 4 81 93 1437
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that there may have been several co
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Roberts, C. M., Hawkins, J. P., McA
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Economic Analysis of Coral Bleachin
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Table 1. Comparison of cost and ben
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changes. In the Seychelles case stu
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ents questioned in Zanzibar came in
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Table 3. Regression results for res
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Table 5. WTP Estimates for Kenya, Z
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Coral Reef Rehabilitation: Feasibil
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Since Kiunga is remote, with low or
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4000 Pavona spp. 4000 Porites spp.
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DISCUSSION AND CONCLUSIONS Recruits
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Obura, D. O., Uku, J. N., Wawiye, O
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such as increased penetration of so
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Table 1. Filter specifications for
Page 271 and 272:
Table 2. The percentage cover of th
Page 273 and 274:
Adresses to Authors S. Ahamada BP 1
Page 275 and 276:
Jelvas M. Mwaura CORDIO East Africa
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