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Coral Reef Survey, Yemen

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					Status of Coral Reefs in Yemen

PERSGA-

S TATUS OF CORAL R EEFS IN YEMEN - 2002
M OS H I R A H A S S A N 1 , M A L E K A. A BD AL -A Z I Z 2 , A R EF H AMO U D 3 , Z A H I R A L -A G W A N
1

ReefCheck Europe & Middle East; Email: moshira@reefcheck.de
2 3

C Email: s o c o t r a v i s @a o l . c o m

C Email: a re f h 8 1 @ h o t m a i l. c o m C Email: a g w a n z @h o t m a i l . c o m

4

1. S UMM ARY
The present study was carried out in Yemen during May 2002. It is part of the regional survey of the Red Sea and Gulf of Aden and was conducted within the Habitat and Biodiversity Program of PERSGA (Regional Organization for the Protection of the Environment of the Red Sea and Gulf of Aden). The study encompassed two main objectives: 1. The rapid assessment of the basic health of and human impact on coral reefs of Yemen in the Red Sea and the Gulf of Aden (Socotra Island) according to the international standard survey methods of Reef Check TM. 2. Intensive training of several nationals, who have a previous experience with the above mentioned methods, standardization of the survey techniques and formation of a national Reef Check-team.

Nine sites were surveyed and compared with respect to human impact, percent cover of several substrate categories, and abundance of certain invertebrate and fish species as well as coral damage. The percent cover of substrate categories varied highly between and within sites. Live hard coral cover ranged from 19% to over 80%, with an average of 42% over all surveyed sites, with the percentage of live coral higher in the Red Sea than off Socotra Island. Some sites were highly deteriorated and showed evidence of past bleaching and COTS events. The corallivorous gastropods (Drupella sp. and Coralliophila sp.) occurred on many transects. Only one lobster and three Triton shells were found in all surveys. Most transects showed some degree of breakage and trash, mainly attributed to anchoring and fishing, but the total amount of direct human damage was low. A large proportion of the coastline of Yemen is only lightly populated, but threats to coral reefs through human impact are increasing rapidly as the coastline is being developed. A problem seems to lie both in local fisheries as well as fisheries from other countries. Nevertheless, on the whole the abundances of indicator species were high, especially for butterflyfish and snappers. While large parrotfish and groupers were found, neither bumphead parrotfish nor humphead wrasses were counted.

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Status of Coral Reefs in Yemen

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2. I NTRODUCTIO N
The survey presented here was part of a regional coral reef monitoring survey conducted during April and May 2002. The study aimed at obtaining a first comprehensive rapid assessment of the coral reef habitats of the Red Sea and of the Gulf of Aden (Socotra Island) with respect to coral reef health, standardization of methods and thus comparability of data throughout the region. The study was commissioned by the Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden (PERSGA). The participation of PERSGA and its member countries in this initiative is important as part of the global exchange of experiences and information in this field and will assist with future work and development. Training of national experts of the PERSGA member states aims at improving national capacity and at enhancing information flow between experts of these nations. In this report we present the results of the first comprehensive and standardized coral reef TM survey undertaken in Yemen using the standard methods of Reef Check . This status report for Yemen is the basis of (together with the other national reports of the PERSGA member countries) the contribution of PERSGA to the publication “Status of Coral Reefs of the World”, issued in by the Global Coral Reef Monitoring Network (GCRMN). Several surveys were undertaken on the reefs of Yemen during the last years using various methods. The results of these studies are summarized in a technical report commissioned by PERSGA in 2000 (Pilcher and DeVantier 2000). The results of the previous surveys are compared with the recent surveys whenever possible.

3. G EOG RAPHICAL S ETTING AND R EEF C OVERAG E
The Republic of Yemen is situated in the southwestern corner of the Arabian Peninsula and borders the Red Sea as well as the Gulf of Aden. The Yemeni coastline extends for some km from the Red Sea, through the Bab el Mandeb and along the Gulf of Aden. Approximately two thirds of Yemen’s coast lies along the Gulf of Aden. The development of reefs varies highly between the different areas of Yemen, with the best developed coral reefs found around offshore islands in the northern part of the Red Sea. The coast of the Gulf of Aden supports much less coral communities. Coral reefs are however abundant around Socotra Island, which bears a unique assemblage of marine fauna and flora due to the island’s geographic isolation in the Gulf of Aden. This study concentrated on reefs in the Red Sea and 2 sites off Socotra Island. (Figure 1).

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Status of Coral Reefs in Yemen

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Figure 1: Map of study sites in the Republic of Yemen showing the sites of the Red Sea and off Socotra Island

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Status of Coral Reefs in Yemen

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4. M ETHODS
Site selection
The sites were selected according to 3 main criteria: 1) to cover a range of different reefs include sites that have been previously surveyed to allow comparison 3) and to provide a baseline for relatively untouched sites which are to be developed in the future. The sites should be representative of the different reef types, biotopes, community types, and include sites with different levels of human disturbance. Due to time const raints, only a few of the possible sites were surveyed. Nine sites were chosen, of which 7 were in the Red Sea and Socotra Island (Figure 1 & table 1).

Site name
Six Foot Rocks (Jabal Makasar) Tuqfash Island Kamaran Island Al Sheikh Faian (NW-Zuqar Is) NNW-Zuqar Island NE-Zuqar Island SWW-Zuqar Island Socotra, Alamah Socotra, Halah

Longitude (E)
degree 042، 042، 042، 042، 042، 042، 042، 053، 054، min (dec) 22.917' 23.308' 32.985' 41.357' 43.907' 47.097' 43.843' 49.522' 21.397'

Latitude (N)
degree 15، 15، 15، 14، 14، 13، 13، 12، 12، min (dec) 40.407' 42.012' 22.990' 01.305' 03.907' 22.729' 57.117' 36.897' 37.115'

Date
6 May 2002 6 May 2002 7 May 2002 9 May 2002 9 May 2002 10 May 2002 10 May 2002 25 May 2002 27 May 2002

Table 1: The survey sites and their geographical positions

Survey methods
The survey method is designed to assess human impact on coral reefs and to monitor these changes over time. It is furthermore designed to be simple and rapid and can thus be easily applied to obtain a first idea of larger areas. The surveys concentrate on categories and species that are indicative of human impact on coral reefs (such as overfishing or destructive fishing practices, pollution or siltation) and that are readily recognizable. Four basic surveys were made at each site: • • • • Site description: is a descriptive survey of the sites and includes information on location, known impacts, known regulations, anecdotal information etc Substrate: The relative abundance of certain substrate categories is assessed using the point intercept method Invertebrates: Certain indicator species of invertebrates as well as observed coral damage, diseases and trash are counted Fish: Certain indicator fish species and groups are counted

Surveys were conducted at a shallow (approx. 4-5m) at all sites, except at Kamaran Island, which did not extend that deep and the survey was conducted at approx. 2m water depth Page 4 of 16

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Status of Coral Reefs in Yemen

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intermediate depth (approx. 10m) was surveyed at the 2 Socotra sites, but not in the Red Sea where reefs were largely absent at this depth.

Four (4) replicate transects of 20m were surveyed at each surveyed depth at each site .

The survey methods are described in detail in the Reef -Check survey manual. Further detailed information on the survey methods can be obtained from the Internet at: http://www.reef check.org.

Softw are and Statistics
Data of % cover were arcsin transformed to reach normal distribution of the data and homogeneity of the variance. Fish & invertebrate abundances were first tested for normal distribution. If data of abundances were not normally distributed, they were log transformed to fulfill requirements for ANOVA testing. ANOVA was conducted for all data to test for differences between sites and Scheffé ‘s test was used for post-hoc comparison For statistical analysis one-way ANOVA was performed. Variables were log transformed when variances were not homogenous and Sheffé's tests were used for post -hoc comparison. Statistical analyses were conducted using StatView 5.0. For further reference see http://www.statview.com

Training
Formal and on-the-job training of national experts constituted a major part of the program. The scientists involved all had previous experience with the methods and so the training concentrated on standardizing the details of the methods. Diving skills were fur ther developed to ensure safe diving and reliable data collection. Care was taken to train a team capable of conducting the full surveys from the planning stage and site selection up to data analysis. Name
Dr. Moshira Hassan Mr. Malek A. Abdal-

Position
PERSGA consultant PERSGA: Habitat and Biodiversity Working Group Member Researcher PERSGA: National Project Co-coordinator

Institution
Reef Check

Aziz
Mr. Aref Hamoud

Mr. Zahir Al-Agwan

Table 2: The work-team members of the coral reef survey in Yemen

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Status of Coral Reefs in Yemen

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5. S TATUS

OF

C ORAL R EEFS

Substrate and Benthos
The mean cover of live hard coral for all of the reefs surveyed in Yemen and over all depths was 42%, with around 48% in the Red Sea and 31% in Socotra (figure 2 and tables 3 & 4). At the difference between the Red Sea and Socotra was greater with the mean for Red Sea being 53% and for Socotra 27% (36% at 10m). Rock was the second highest substrate category with an overall average of approx. 24% both areas. Recently killed coral was low on average (average < 1%) on the surveyed reefs, several transects revealed more than 2% and a large proportion of the rock, especially in the Red Sea, appears to be coral that died within the last 5-8 years. Rubble made up a higher proportion of the substrate in the Red Sea (13%) than in Socotra (5%). Very little sponges or soft coral were found in the Red Sea, but reached 5% and 6% respectively in Socotra. Fleshy seaweed was also higher in Socotra (8%) than in the Red Sea (3%).
70

Substrate categories:
Yemen, Red Sea Yemen, Socot ra

60

HC – hard coral SC – soft coral RKC – recently killed coral FS – fleshy seaweed SP – sponge RC – rock RB – rubble SD – sand SI – silt

50

40

30

20

10

0 HC SC RKC FS SP RC RB SD SI OT

c o v e r ( % )

S u b s t r a t e

OT – other

Figure 2: Average percent cover over all sites and depths of the 10 substrate categories surveyed. Error bars represent standard deviations

The percent cover of substrate categories varied highly between and within sites. Live hard coral cover ranged from 19% in Kamaran Island to over 69% at Zuqar Island (SW). Two transects, one at Al Sheikh Faian (NW-Zuqar Island) and one at Zuqar Island (SW) reached 83 and respectively (Figure 3). The overall % cover of hard corals did not change significantly since the previous summary survey commissioned by PERSGA in 2000. Kamaran Island differed most from all other sites with respect to substrate cover. Hard coral was significantly lower (19%, p< 0.0005) than at all other sites while rubble was significantly higher (p =0.005 - 0.0005) than at any other site. The surveys revealed highly deteriorated reefs, with an average of 30%. Similar observations had been made previously by Jeremy Kemp (pers. comm.). Fishing of aquarium fish and their trade is increasing in Yemen, especially in the northern waters of the Red Sea in Yemen, and Kamaran in particular. Destructive fishing methods were r eported to have taken place occasionally at this site (information from local fishermen).

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Only the two Socotra sites were surveyed both at shallow and at intermediate depth. The differences between depths were not significant for hard coral at Halah, but much higher at shallow depth (43%) than at the intermediate depth (25%) in Alamah. However, Halah showed the highest percentages fleshy seaweed and of sponges of all other sites with fleshy seaweed reaching 14% in the shallow depth at this site and sponges attaining 16% at the intermediate depth. Reefs of the Yemeni coast were also surveyed at < 2m water depth where living hard coral cover ranged from 15% in Mukalla to 69% in Belhaf (Wilson, pers. comm.). Recently killed coral reached 2% at several of the sites. Despite the high percentage in living coral cover, the general state of some of the surveyed reefs seems to have declined over the last years.

Figure 3: Average percent cover by hard coral at each site and depth. Error bars represent standard deviations

Figure 4: Average percent cover by rock at each site and depth. Error bars represent standard deviations.

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Status of Coral Reefs in Yemen

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Figure 5: Average percent cover by fleshy seaweed at each site and depth. Error bars represent standard deviations

Figure 6: Average percent cover by sponge at each site and depth. Error bars represent standard deviations

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Status of Coral Reefs in Yemen

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Among the indicator invertebrate species, the low abundance of several groups was conspicuous, namely the Triton gastropod, of which only three individuals were found during all surveys and lobsters, of which only one was spotted. Sea cucumbers were present on most sites. Their abundance has decreased however since they started being fished for export to SE (information from fishers). The bioeroding sea urchin Diadema however were abundant in some sites. It averaged individuals per 100m2 on Red Sea sites, the highest finding for this species throughout the region 2 and 18/100m on Socotra. High numbers of the corallivorous gastropods (Drupella sp. and Coralliophila sp.) were found on several transects, and at least one COTS was found on most sites (figure 7). Physical coral damage (breakage) was present at all sites, but low at most sites. Some trash, mostly fishing lines, was found on most sites, but was also rated as very low. While the effect of previous bleaching events was visible (especially in Kamaran, see above), freshly bleached corals were rare.

Figure 7: Indicator species of invertebrates. Average number of individuals per 100m2. Error bars represent standard deviations.

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Status of Coral Reefs in Yemen

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Fish Communities
Fish abundances varied greatly. Differences within sites were generally larger, though, than between sites, but no significant differences were observed between depths. Butterfly fish averaged 9/100m . Abundances reached 24 individuals per 100m at Zuqar SW and 19 individuals per 100m2 at Halah, Socotra. Abundance was lowest at Kamaran. The highest number of groupers was found on Socotra where they reached 6 individuals per 100m2, whereas none were found at Kamaran. The numbers of snappers were very high with an average of 100/100m , and ranged from 2 2000/100m ). Large schools of the snappers Lutjanus kasmira & L. quinquelineatus were found on many of the reefs. In addition schools of 3-10 sea breams (Acanthopagrus bifasciatus) were also observed on many of the reefs. Neither bumphead parrotfish, nor any humphead wrasses were found on any of the surveys.
2 2 2

Figure 8: Major indicator species (groups) of fish. Average number 2 of individuals per 100m over all sites surveyed in Yemen. Error bars represent standard deviations.

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Figure 9 Abundance of major indicator species (groups) of fish at various sites in Yemen: Butterflyfish, Groupers and Parrotfish. 2 Average number of individuals per 100m . Error bars represent standard deviations .

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Status of Coral Reefs in Yemen

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6. C ONCLUSIONS

AND

R ECO MM ENDATIONS

Overall most of the reefs surveyed in Yemen, both in the Red Sea as well as on Socotra, were in relatively good condition, despite increasing human impacts. However, signs of deterioration of coral reefs have been reported over the last years. High numbers of the corallivorous gastropods and at least one COTS was found on most sites. The bioeroding urchin Diadema averaged individuals per 100m2 on Red Sea sites, the highest finding for this species throughout the region These findings are reason for concern, and the reefs should be closely monitored and protection measures enforced to avoid further deterioration of the reefs. Despite the increasing fishing pressure from local as well as foreign fishermen, the abundance of indicator fish was among the highest in the Red Sea. Butterfly fish averaged 2 2 9/100m . The numbers of snappers were very high with an average of 100/100m , and ranged 2 from 24- 2000/100m ). Public awareness regarding coral reef conservation is low in Yemen and the legal framework to protect coral reefs is not highly developed, except for on Socotra Island, which is a declared National Park and receives much attention in research and international funding. As coastal development and maritime transport continue to increase in a largely unchecked manner, creating additional stress on the already fragile reefs, while environmental awareness remains low, the threats to coral reefs in Yemen are increasing. Environmenta l awareness needs to be increased in the population and development needs to be exercised carefully, as the country is dependent on the reefs with fish, including reef fish, constituting an important part of the people’s diet.

7. R EFERENCES
DouAbul, A., Rouphael, T., Marchant S., and Marchant R. (eds.) (1999) Protection of Marine Ecosystems of the Red Sea Coast of Yemen. Prepared by Hassal and Associates and Australian Marine Science and Technology Ltd. for the United Nations Office for Project Services Hodgson, G. (1999). A global assessment of human effects on coral reefs, Marine Pollution Bulletin 38 345-355. Pilcher, N. and DeVantier, L. (2000). The Status of Coral Reefs in Yemen. PERSGA technical reports 2000 pp47. Reef Check survey instruction manual. Publications of the Reef Check Program. (http://www.reefcheck.org

‫ﻣﻨﺴﻘﺔ:ﺗﻌﺪادات ﻧﻘﻄﯿﺔ ورﻗﻤﯿﺔ‬

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8. A CKNO W LEDGEMENTS
This report was prepared under the auspices of PERSGA. We would like to thank the members of the survey team and for their enthusiasm and support. This survey was only possible with the continuous support of Mr. Abdullah Alsuhaibany, and Mr. Mohamed Anis Younis. Fouad Nasseb, Thabett Khamis and Mohammed Ismail were enthusiastic members of the survey team in Socotra. We would also like to thank Simon Wilson and Jeremy Kemp for their valuable input and information of previous surveys.

‫ﻣﻨﺴﻘﺔ:ﺗﻌﺪادات ﻧﻘﻄﯿﺔ ورﻗﻤﯿﺔ‬

9. A PPENDIX
This appendix includes summary tables for substrate categories, indicator invertebrate species and indicator fish. The raw data are a lso available in the form of excel sheets.

Substrate type Mean HARD CORAL SOFT CORAL RECENTLY KILLED CORAL FLESHY SEAWEED SPONGE ROCK RUBBLE SAND SILT OTHER 47.8 0.1 0.6 2.8 0.3 24.0 12.9 7.2 0.0 4.4 Std. Dev. 20.4 0.5 2.0 4.0 0.8 13.0 12.5 10.2 0.0 6.2 Count 28 28 28 28 28 28 28 28 28 28 Maximum 82.5 2.5 10.0 15.0 2.5 57.5 65.0 45.0 0.0 25.0

Table 3: Mean percent cover (%) of various substrate categories at Yemen sites in the Red Sea (all sites)

Substrate type Mean HARD CORAL SOFT CORAL RECENTLY KILLED CORAL FLESHY SEAWEED SPONGE ROCK RUBBLE SAND SILT OTHER 31.4 6.4 0.8 7.7 4.8 25.0 5.3 8.3 0.0 10.3 Std. Dev. 8.9 4.4 2.0 5.1 8.9 11.4 2.7 4.3 0.0 4.8 Count 16 16 16 16 16 16 16 16 16 16 Maximum 52.5 15.0 7.5 15.0 30.0 42.5 10.0 17.5 0.0 20.0

Table 4: Mean percent cover (%) of various substrate categories at Yemen sites in Socotra, Gulf of Aden (both sites and both depths)

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Status of Coral Reefs in Yemen Substrate type Mean HARD CORAL SOFT CORAL RECENTLY KILLED CORAL FLESHY SEAWEED SPONGE ROCK RUBBLE SAND SILT OTHER 41.8 2.4 0.7 4.5 1.9 24.3 10.2 7.6 0.0 6.5 Std. Dev. 18.8 4.0 2.0 5.0 5.7 12.3 10.7 8.5 0.0 6.4 Count 44 44 44 44 44 44 44 44 44 44

PERSGA-

Maximum 82.5 15.0 10.0 15.0 30.0 57.5 65.0 45.0 0.0 25.0

Table 5: Mean percent cover (%) of various substrate categories at Yemen all site and depths.

Hard Coral (HC) Mean Total Alamah (Socotra) Halah (Socotra) Kamaran Isl. Six Foot Rocks Tiqfash Island Zuqar Island, NE Zuqar Island, NNW (Zuqar 2) Al Sheikh Faian (NW-Zuqar) Zuqar Island, SW 41.8 34.1 28.8 19.4 28.1 50.6 46.9 52.5 68.1 68.8 Std. Dev. 18.8 11.4 5.0 14.6 12.5 10.3 6.0 6.1 17.6 11.1 Count 44 8 8 4 4 4 4 4 4 4 Maximum 82.5 52.5 35.0 37.5 40.0 60.0 52.5 60.0 82.5 80.0

Table 6: Mean percent cover (%) by hard corals at each site.

Rock (RC) Mean Total Alamah (Socotra) Halah (Socotra) Kamaran Isl. Six Foot Rocks Tiqfash Island Zuqar Island, NE Zuqar Island, NNW (Zuqar 2) Al Sheikh Faian (NW-Zuqar) Zuqar Island, SW 24.3 30.9 19.1 39.4 26.2 21.9 25.3 21.9 12.5 20.6 Std. Dev. 12.3 9.9 9.9 21.3 16.1 6.2 8.3 8.3 5.0 8.3 Count 44 8 8 4 4 4 4 4 4 4 Maximum 57.5 42.5 30.0 57.5 50.0 30.0 32.5 32.5 20.0 30.0

Table 7: Mean percent cover (%) by rock at each site.

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Status of Coral Reefs in Yemen Indicator invertebrates Diadema Mean (no. / 100m ) Pencil urchin Sea cucumber Crown-of-thorns Giant clam (Tridacna sp.) Triton Lobster Table 8: Mean abundance of indicator species of invertebrates (4m and 10m combined) 25.1 0.2 4.2 0.5 0.6 0.1 0.0 48.7 0.5 8.1 1.1 1.2 0.5 0.2 44 44 44 44 44 44 44 220 2 43 5 5 3 1
2

PERSGAStd. Dev. Count Maximum

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Status of Coral Reefs in Yemen Indicator fishes Mean (no. / 100m ) Butterfly fish, Total Butterfly fish, shallow Butterfly fish, medium Sweetlips, Total Sweetlips, shallow Sweetlips, medium Snapper, Total Snapper, shallow Snapper, medium Broomtail wrasse (Cheilinus lunulatus), Total Broomtail wrasse (Cheilinus lunulatus), shallow Broomtail wrasse (Cheilinus lunulatus), medium Grouper (>30cm), Total Grouper (>30cm), shallow Grouper (>30cm), medium Bumphead parrotfish, Total Bumphead parrotfish, shallow Bumphead parrotfish, medium Humphead wrasse (C. undulatus), Total Humphead wrasse (C. undulatus), shallow Humphead wrasse (C. undulatus), medium Parrotfish (>20cm), Total Parrotfish (>20cm), shallow Parrotfish (>20cm), medium Moray eel, Total Moray eel, shallow Moray eel, medium 8.6 7.8 8.8 5 2 5.7 65.8 7.4 78.8 0.1 0 0.1 1.4 3.5 0.9 0 0 0 0 0 0 2.1 2.8 2 0.1 0.4 0 5.3 4.5 5.6 10.5 1.5 11.5 301.2 4.6 332.4 0.3 0 0.4 1.5 1.5 1 0 0 0 0 0 0 1.8 1.6 1.8 0.3 0.7 0 44 8 36 44 8 36 44 8 36 44 8 36 44 8 36 44 8 36 44 8 36 44 8 36 44 8 36
2

PERSGA-

Std. Dev.

Count

Maximum 24 16 24 63 5 63 2000 14 2000 2 0 2 6 6 3 0 0 0 0 0 0 7 5 7 2 2 0

Table 9: Mean abundance of indicator species of fish (all Yemen sites)

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Description: The present study was carried out in Yemen during May 2002. It is part of the regional survey of the Red Sea and Gulf of Aden and was conducted within the Habitat and Biodiversity Program of PERSGA (Regional Organization for the Protection of the Environment of the Red Sea and Gulf of Aden).