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MGM 173 Science Report Price, N and Cryer, S

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MADAGASCAR MARINE CONSERVATION

RESEARCH PROGRAMME

Nosy Be, Madagascar

MGM Phase 173 Science Report

12th June – 4

th September

Nathan Price and Sarah Cryer


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Contents

Staff Members .................................................................................................................................... 3

1. Introduction ................................................................................................................................ 4

1.1 Aim ........................................................................................................................................ 5

1.2 Objectives .............................................................................................................................. 5

2. Training ....................................................................................................................................... 6

2.1 Briefing ............................................................................................................................. 6

2.2 Science Lectures ............................................................................................................... 6

2.3 Practical Instruction ............................................................................................................. 7

2.4 Dive Training ........................................................................................................................ 7

2.5 Tropical Habitat Conservation – Business Training and Educational Council (BTEC)

Students ....................................................................................................................................... 7

3. Research Program ......................................................................................................................... 8

3.1 Biological Monitoring of Coral Reefs in the Nosy Vorona Bight: Baseline Survey

Protocol ...................................................................................................................................... 8

3.1.1 Introduction ........................................................................................................................ 8

3.1.2 Methodology ....................................................................................................................... 9

3.1.2.1 Survey Sites .............................................................................................................. 9

3.1.2.2 Methodology .......................................................................................................... 10

3.1.2.3 Statistical Analysis ................................................................................................. 11

3.2.3 Results .............................................................................................................................. 12

3.2.3.1 Fish Assemblage Status ......................................................................................... 12

3.2.3.2 Benthic Status ........................................................................................................ 13

3.2.3.3 Invertebrate Status ................................................................................................. 13

3.3 Discussion ........................................................................................................................... 15

3.4 Mangrove Systems............................................................................................................. 16

3.4.1 Introduction .............................................................................................................. 16

3.4.2 Methodology ............................................................................................................. 17

3.4.3 Results ....................................................................................................................... 23

3.5 Marine Litter ..................................................................................................................... 23

3.5.1 Introduction .............................................................................................................. 23

3.5.2 Methodology ............................................................................................................. 24


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3.5.3 Results ....................................................................................................................... 24

3.5.4 Discussion ................................................................................................................. 26

3.6 Nudibranch Survey ........................................................................................................... 26

3.6.1 Introduction .............................................................................................................. 26

3.6.2 Methodology ............................................................................................................. 27

3.6.3 Results ....................................................................................................................... 27

3.6.4 Discussion ................................................................................................................. 28

3.7 Research Projects .............................................................................................................. 28

3.7.1 Introduction .............................................................................................................. 28

3.7.2 Methodology ............................................................................................................. 29

3.7.3 Potential Outcomes................................................................................................... 29

3. Proposed Work Programme for Next Phase .......................................................................... 30

5. References ..................................................................................................................................... 30

Staff Members

Nathan Price (NP)

Magnus Jansen (MJ)

Sarah Cryer (SC)

Ella Garrud (EG)

Victor (V)

Principal Investigator (PI)

Dive Officer (DO)

Assistant Research Officer (ARO)

Assistant Research Officer (ARO)

Local Staff (LS)


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1. Introduction

There is a serious ecological decline in coral reefs, and it is estimated approximately 30% of coral

reefs worldwide have suffered serious damage; with predictions that by 2030 virtually 60% of coral

reefs may be lost (Hughes et al. 2003). Despite the damage caused to coral reefs, they are highly

valued ecosystems that play important roles, providing ecosystem goods and services for millions all

around the world. Many factors contribute to the worldwide degradation of coral reefs, the most

common being overfishing and climatically induced coral bleaching (Hughes et al. 2003; Bellwood et

al. 2004). Such negative impacts are changing the structure of coral reefs, causing them to shift from a

hard-coral dominated state to algae, seaweed, soft coral and sponge dominated states (Bellwood et al.

2004). Long-term ecological impacts of phase-shifts include loss of invertebrate, fish and coral

diversity and abundance (Jackson et al. 2001).

Madagascar is the fourth largest island in the world with over 5,000 km of coastline, supporting

extensive fringing reef systems (Cooke et al. 2000). Approximately 3,500 km of the coastline is

fringed with scleractinian dominated coral reefs, which are highly productive and dynamic

ecosystems. With 55% of the population of Madagascar living on the coast, over half of the nation is

heavily reliant on fisheries (Le Manach et al. 2011).

Foreign aid has recently been withdrawn from Madagascar and landing reports have largely gone

unregulated and unreported by an estimated 40%, leading to extremely poorly managed fish and

invertebrate stocks. The unregulated fishing has led to the continuing depletion of commercial

important Holothurians and most of the large species native to the waters of Madagascar (Le Manach

et al. 2012).

There are two fully decreed marine protected areas (MPAs) in Madagascar and multiple locally

managed marine areas (LMMAs) however only 2% of the country’s coral reefs are located within

protected zones and the majority of fisheries are regarded as unsustainable. Even with imposed area

and fishing restrictions, there is little enforcement and the exploitation of many marine invertebrate

and fish species continues to occur, leading to increased levels of bio-eroders such as sea urchins that

contribute to overall reef decline. Presently much of Madagascar’s marine resources are depleted,

leaving a legacy of reduced fisheries catch and a continuing decline toward an unstable level of

overall species abundance and diversity.

Biomonitoring of coral reefs around the world is essential to our understanding of their health and

resilience, and enables us to research into the mechanisms that regulate such ecosystems. Baseline


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data with repeat monitoring is crucial to further understand anthropogenic impacts on marine

ecosystems. Detailed scientific data regarding fish assemblages, influential invertebrate species

abundances, and coverage of benthic substrata are needed to understand ecological processes.

Frontier is a conservation NGO that has worked out of the village of Ambalahonko on the island of

Nosy Be in Northwest Madagascar since 2010. Trained scientists as well as volunteer research

assistants have been contributing to a long-term biomonitoring program documenting fish, macro

invertebrate assembles, nudibranch abundance and diversity, benthic community composition and the

status of marine debris on the beaches surrounding Ambalahonko.

1.1 Aim

The general aim of the research is to conduct extensive documentation to gain an understanding of the

health of the coral reefs and mangroves in Nosy Vorona Bight in Northwest Madagascar. To gain a

broad understanding of the current health of the reefs, sites were chosen across coral dominated

habitats, seagrass beds, and sponge dominated habitats.

1.2 Objectives

Further to the broad aim listed above, there are various objectives which must be completed to

investigate the aim:

Objective 1 - To assess the fish community in Nosy Vorona Bight using data collected from

underwater visual census.

Objective 2 – To assess the key invertebrate species using data collected from invertebrate surveys,

using Reef Check methodology.

Objective 3 – To document the benthic community composition using line-intercept transect in the

Nosy Vorona Bight.

Objective 4 – To investigate the abundance and diversity of nudibranchs in the Nosy Vorona Bight,

using active searches.

Objective 5 - To assess the health of the mangrove systems close to Ambalahonko using data

collected every 10m along a transect with a 5x5m quadrat and a smaller 2x2m quadrat used to count

the number of adults, saplings, and seedlings. The number of dead trees, crab holes and

pneumatophores are also counted.


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2. Training

2.1 Briefing

Initial talks on camp logistics, health and safety, dive operations and the MGM project were delivered

within the first few days of the volunteers arriving on camp (Table 1).

Table 1. Briefing sessions conducted during phase 173.

Briefing Contents of the talk

Introduction to Camp An initial introduction to the facilities on camp

Health and Safety Raising awareness of potential health and safety issues that may be

encountered during an expedition.

Dive Operations Tour around camp to show the volunteers the diving facilities and

equipment.

Introduction to MGM Tour around camo to show the volunteers the science hut, and science

resources, with some background to the species groups and surveys.

2.2 Science Lectures

A number of science lectures were given and documentaries shown throughout the phase (Table 2).

Those used in previous phases were updated, new lectures and tests were created to aid in learning

which proved successful. ‘Extra curriculum’ lectures or conservation programmes were shown to

RA’s at least once a week during this phase, and documentaries were shown once every two weeks.

Table 2. Lectures and documentaries provided during Phase 173.

Presentation Contents

Introduction to MGM A basic background into coral reef ecology and conservation

biology, along with the different projects currently being

undertaken by MGM, and introducing the roles of the volunteers

into the overall research project.

Territorial Fish An introductory lecture designed to introduce the various fish

families that predominantly show territorial behaviour. After fish

family backgrounds, the volunteers are introduced to individual

species they will observe during surveying.

Schooling Fish An introductory lecture designed to introduce the various fish

families that predominantly schooling. After fish family

backgrounds, the volunteers are introduced to individual species

they will observe during surveying.


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Invertebrates An introductory lecture with the background of marine

invertebrates, with much of the emphasis into on the target species

that are observed during the surveys.

Nudibranchs An introductory lecture into nudibranch biology, with much of the

focus on nudibranch identification.

Benthic Basic introduction to benthic ecology, with much of the focus on

coral and algae biology, coral growth forms and threats to the

benthic ecosystem.

Survey Methodologies Basic background into underwater survey methodologies,

particularly survey methodologies conducted at Frontier.

Mangrove Ecosystems Background into mangrove ecosystems, including ecosystem

services, taxonomy and threats.

Sharkwater (documentary) Documentary about the worldwide shark finning trade.

End of the Line (documentary) Documentary about overfishing.

Racing Extinction (documentary) Documentary about anthropogenic threats to ecosystems around

the world.

Chasing Coral Documentary about ocean acidification and threats faced by coral

reefs.

2.3 Practical Instruction

After initial lectures on the research topics, practical training is provided. A large proportion of the

education is developing identification skills for the benthos, invertebrates and the fish species, where

this is direct instruction from staff or independent learning. Pointy snorkels and dives were used to

develop in-water identification skills, and to ensure the volunteers knew what they were seeing. All

volunteers had to pass a computer test (30 questions) and in-water test (20 questions) for the chosen

research topic. The pass mark for all the tests is 95%.

2.4 Dive Training

Please see the dive report for all diving training undertaken during this phase.

2.5 Tropical Habitat Conservation – Business Training and Educational Council (BTEC)

Students

There have been no volunteers completing their Topical Habitat Conservation BTEC during this

phase.


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3. Research Program

3.1 Biological Monitoring of Coral Reefs in the Nosy Vorona Bight

3.1.1 Introduction

Coral reefs are subject to a high frequency of recurrent biological and physical disturbances, and they

have significant aesthetic and commercial value, particularly in relation to fisheries, coastal protection

and tourism. Coral reefs only cover between 0.5-1% of the world’s oceans but they are particularly

diverse, containing almost a third of all know fish species (McAllister, 1991). However many reefs

around the world are extremely threatened, owing primarily to over-harvesting (Jackson et al. 2001),

pollution (Hughes and Connell 1999), disease (Hughes and Tanner 2000) and climate change (Hughes

1994).

Fish, invertebrate and coral species are used to monitor the health of coral reefs all around the world.

Examining the interconnectivity and relationships between proximal habitats in many coral reef

environments is vital for understanding the dynamics of coral reef fish assemblages (Wilson et al.

2010). Habitat selectivity and specificity is documented within many species and is shaped by a

variety of processes such as responses to predation, foraging efficiency or reproduction. Considering

the decline of coral reefs and near shore habitats worldwide, this is cause for concern; the knock-on

effects of coral loss or mangrove removal will undoubtedly affect species that have habitat specific

recruitment (Honda et al. 2013). Understanding coral reef fish ecology is important, especially in

developing countries such as Madagascar where reliance on natural resource extraction is, in some

places, the only means of survival (Le Manach et al. 2012).

Macro invertebrates can play a vital role in the food webs of marine ecosystems, as well as

contributing to bio-turbation and bio-erosion of coral reefs, the latter of which can have an effect on

successful coral settlement (McClanahan et al. 1999). The symbiotic relationships of these

invertebrate families with scleractinian corals, sponge, soft coral, sand, algae and seagrass directly and

indirectly affect the overall health of reefs. Sessile animals that form the substrata of different

biotopes compete for space, largely based on life form, colonial or solitary, with different phyla of

animals gaining success in certain areas (Jackson, 1997). Warmer water temperatures, causing a

higher acidity level and an increase in dissolved inorganic carbon, prevent the growth of calcifying

organisms including scleractinian corals, crustose coralline algae, and some invertebrates (Caldeira

and Wickett, 2003).

There are many documented anthropogenic threats to coral reefs in Madagascar, such as

sedimentation due to intensive agriculture and damaging fishing practices. Many families in

Madagascar rely solely on coral reefs as their primary source of protein, and fishing is often the only


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economic income for young adults across the country. Given the importance of coral reefs to local

inhabitants of Madagascar, documentation and investigating into the health of coral reefs is crucial.

Biological monitoring of the reef systems around Nosy be will hopefully feedback into the

implementation of management strategies. The MGM research program contributes to the continual

assessment of coral reefs in North-West Madagascar, by undertaking regularly surveying at 5

permanent sites.

3.1.2 Methodology

3.1.2.1 Survey Sites

During Phase 173, fish and invertebrate assemblages along with benthic composition were examined

at several sites within the Nosy Vorona Bight in Northwest Madagascar (Fig 1; Table 3).

Figure 1: Location map of sites surveyed in the Nosy Vorona Bight during Phase 173.


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Table 3. Description of the study sites surveyed in phase 173.

Site Depth

Range (m)

GPS Description

Nosy

Vorona

2.0-10.0 13°25’30”

S,

48°21’46”

E

Fringing patchy reef formed around a small island,

dominated by live coral. Moderate live coral cover with

extensive coral rubble and patchy seagrass beds. Little

terrestrial influence, strong current, artisanal fishing pressure.

Temperature range 27°-31°C.

Three

brothers

2.0-7.0 13°25’53”

S,

48°21’50”

E

Fringing mix of continuous and patchy reef formed around

three distinct outcrops, dominated by live coral. Moderate

live coral cover, little terrestrial influence, moderate fishing

pressure. Temperature range 27°-31°C.

Turtle

Towers

3.0-11.10 13°26’48” S

48°20’09”

E

Large continuous reef with moderate live fringed coral reef,

dominated by live coral. There are several small artificial

reef systems, and a small scale MPA to prevent fishing and

anchor damage. Temperature range 27°-31°C.

Blue

Pillars

3.0-10.0 13°27’06”

S,

48°19’39”

E

Large live and healthy coral reef, dominated by hard coral

and extensive seagrass beds. Temperature range 27°-31°C.

Area 51 5.0-16.00 13°25’27”S,

48°20’71”E

Large live coral and sponge site in the middle of the Vorona

bight. Strong currents and often high sedimentation.

Temperature range 27°-31°C.

3.1.2.2 Methodology

Each Baseline Survey Protocol (BSP) was conducted using five different researchers focusing on a

given topic. The roles included physical surveyor, benthic surveyor, invertebrate surveyor, territorial

fish surveyor and schooling fish surveyor (Table 4). The surveys were conducted either with Self-

Contained Underwater Breathing Apparatus (SCUBA) or snorkelling gear, depending on the depth of

the site and the conditions on the day. At each survey site, the physical surveyor along with the

schooling fish surveyor would descend to the seabed, and weight the start of the transect line and

proceed to run out the entire 80m transect. Each transect consisted of three 20m sections with a 10m

redundant section between (i.e. 0-20, 30-50, 60-80). The remaining three surveyors followed


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afterwards undertaking their own individual responsibilities. All surveys were conducted within two

hours of high tide either side, as to standardize the conditions for the presence of fish. In each site, a

minimum of 4 replicate surveys was performed to ensure accurate statistical analysis.

Table 4. Roles and responsibilities of all members of the BSP survey team.

Position Responsibilities

Physical Surveyor Record physical parameters at the site, including site, date, time,

water temperature, depth, cloud cover, sea state and number of

fishing boats present.

Territorial Fish Surveyor Swims along the entire transect recording all territorial fish (species

and abundance) within a 5m2 area along the transect.

Schooling Fish Surveyor Swims along the entire transect recording all schooling fish (species

and abundance) within a 5m2 area along the transect.

Invertebrate Surveyor Swims in a zigzag pattern along the transect line, up to 2.5m each

side of the line and records species and abundance of invertebrates.

Benthic Surveyor Swims along the transect recording all changes in substrate along the

transect line.

Figure 2: Procedure for completing underwater visual census of one 20m section of the BSP. All fish

observed in the 5m2 box are recorded by the surveyor.

3.1.2.3 Statistical Analysis

Excel (Microsoft, USA) and SPSS v23 were used for statistical analysis of these data. All calculated

averages are arithmetic means, and all error bars shown are either standard deviation or standard error

of the mean. A Levene’s test was used to test for homogeneity of variance between data. If the data

had similar variances, ANOVA comparisons were used. If the variances of the data were different the

non-parametric Kruskal-Wallace test was used.


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3.2.3 Results

3.2.3.1 Fish Assemblage Status

A total of 12,104 fish were observed over a 10-week period, during this phase, representing 45

different families and 100 species. The majority of the fish identified belonged to families;

Caesionidae, Labridae and Pomacentridae. The average fish abundance per survey ranged from 239

(±90) at Area 51 to 456 (±61) at Turtle Towers, (F4, 38 = 4.26, p = 0.02; Figure 3.0). With the

exception of Area 51, the survey sites had similar fish family richness, the average fish family

richness ranged between 9.6 (±1.2) at Area 51 and 13.4 (±1.3) at Nosy Vorona (KW H4 = 6.22, p =

0.183; Figure 4). The Shannon-Weiner Biodiversity Index scores for fish ranged between 1.7 at Blue

Pillars and 2.3 at Three Brothers (Figure 5). Three brothers had the highest average fish abundance,

and Shannon-Weiner Biodiversity index, but a low fish family richness.

Figure 3.0 – Average fish abundance for each survey site (±SE).

Figure 4.0 – Average fish family richness for each survey site (±SE).

0

100

200

300

400

500

600

Blue Pillars Nosy Vorona Three Brothers Turtle Towers Area 51

Ave

rage

Fis

h A

bu

nd

ance

Fish Abundance

0

2

4

6

8

10

12

14

16


Ave

rage

Fis

h F

amily

Ric

hn

ess

Fish Family Richness


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Figure 5.0 - Shannon-Wiener Diversity Index for fish at each survey site (±sd).

3.2.3.2 Benthic Status

The average live coral cover ranged from 10% at Nosy Vorona, to 46% at Blue Pillars, these

differences between survey sites were statistically different (F4, 16 = 7.28, p = 0.002). The average

dead coral cover ranged from 2.4% at Area 51, to 15.6% at Turtle Towers, and these differences were

not statistically different (KW H4 = 6.799, p = 0.147). Further analyses can be conducted when more

data has been collected.

Figure 6.0 – Average live and dead coral cover at each of the survey sites (±SE).

3.2.3.3 Invertebrate Status

A total of 14715 invertebrates were recorded over a three-month period. 12951 echinoderms, 178

holothurians and 56 asteriodeans (Figure 7). Of the 12951 echinoderms recorded, 12284 were

Diadema setosum. General abundance of highest at Nosy Vorona, with an average of 675 individuals

per survey, and Blue Pillars had the lowest with only 256 (F4,38 = 4.36, p = 0.006; Figure 7). Species

0.00

0.50

1.00

1.50

2.00

2.50


Div

ers

ity

Ind

ex

Shannon-Wiener Diversity Index

0

10

20

30

40

50

60

Blue Pillars Three Brothers Nosy Vorona Turtle Towers Area 51

Ave

rage

Co

vera

ge (

%)

Coral Cover

Live Coral Cover Dead Coral Cover


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groups (i.e. Nudibranchs, Bivalves etc) were removed from analysis, and diversity was generally low

across all sites, with Nosy Vorona and Area 51 with the highest results and Three Brothers with the

lowest (F 4,34 = 5.541, p = 0.002, Figure 8). When analysing the Shannon-Wiener diversity indices,

only organisms identified to species level were included. Three Brothers had the highest factor, with

Blue Pillars showing the lowest abundance (Figure 9). As standard, results <2.0 were considered very

poor diversity (Gering et al. 2002).

Figure 7.0 – Average invertebrate abundance for each site (±SE)

Figure 8.0 - Average invertebrate diversity for each survey site (±SE). Only organisms identified to

species level were included in the analysis.

0

100

200

300

400

500

600

700

800

Blue Pillars Turtle Towers Nosy Vorona Three Brothers Area 51 Ave

rage

Inve

rte

bra

te A

bu

nd

ance

Invertebrate Abundance

0

1

2

3

4

5

6

7

Blue Pillars Turtle Towers Nosy Vorona Three Brothers Area 51

Ave

rage

Inve

rte

bra

te D

ive

rsit

y

Invertebrate Diversity


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Figure 9.0 - Shannon-Wiener Diversity Index for invertebrates at each survey site (±sd).

3.3 Discussion

The fish assemblages, invertebrate community and benthic community composition all contribute to

the overall picture of coral reef health. The abundance and diversity of fish varied across each of the

sites with at least 200 fish, from at least 9 different families documented. Most of the sites were

dominated by small territorial fish from the Pomacentridae family and small schooling fish from the

Caesionidae family. The lack of large predatory fish is of concern and may well be the reason for the

massively high D. setosum numbers. Area 51 has the lowest number of species and lowest family

richness out of all the sites as well as having a large proportion of sponge habitat in relation to coral,

and the average coverage of coral is the lowest when compared to the other survey sites. Coral

associated species from the families Pomacentridae and Chaetodontidae rely on scleractinian corals,

particularly branching corals, for shelter, protection and as a food source (Cole et al. 2008).

Historically research suggested that corals were largely inaccessible as a viable prey source and that

there were very few fishes capable of feeding directly on corals however trophic studies of coral reef

fish communities have recognised corallivores as a distinct functional group. Randall (1974)

considered corallivores to be one of the most specialised feeding guilds encompassing some of the

most evolutionarily advanced fishes on coral reefs.

Many wrasse feed upon small bivalves, decapods, gastropods, and algae, most of which are often in

high abundances on many coral reefs and seagrass beds. These food sources are less abundant in

sponge habitat, which may explain the low fish diversity and abundance in Area 51. The similarities

in the sites may be attributed to the sites being relatively close and therefore subject to very similar

biotic and abiotic factors. Recently observational dives at the Tanikely Marine Protected Area (MPA)

0.00

0.50

1.00

1.50

2.00

2.50

Blue Pillars Turtle Towers Nosy Vorona Three Brothers Area 51

Div

ers

ity

Ind

ex

Shannon-Wiener Diversity Index


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show large numbers of schooling pelagic fish, and large predatory fish, it is clear their fishing effort

and fishing strategies are managed effectively in this area, when compared to our survey sites.

Corals are the foundation species of coral reef ecosystems, forming the predominant structural habitat

and the foremost contributors to reef development and growth (Jones et al. 1994). The coral examined

at the survey sites shows a variety of results. Blue Pillars displayed excellent hard coral coverage,

while Area 51 and Nosy Vorona were relatively low. The average coral cover from all our sites

combined is 26%, which compares with the global average of 33% reported in 1999 (Hodgson, 1999),

with low levels of dead coral cover. However, at Turtle Towers the dead coral coverage was 15%.

Previous research in Northern Madagascar found dead coral cover to generally be less than 10%

(Webster and McMahon, 2002). Such studies are becoming even more important with climate induced

climate change increasing. Analysis of temperature and other physical climate variables suggest the

region has a more stable temperature regime than areas farther north and south (Maina et al. 2007),

this is most likely the reason why the north-western Madagascar reefs did not bleach in 1998

(McClanahan et al. 2008).

Invertebrate diversity was very limited in this phase. There were low abundances of holothurians and

all of the invertebrate assemblages were dominated by D. setosum. A high abundance of D. setosum

generally occurs when there is overfishing of predatory fish, and indirectly overfishing of herbivorous

fish. When herbivorous fish are removed from the ecosystem, the algae abundance increases.

Triggerfish are a major predator of D. setosum and barely any were sighted in phases 172 and 173.

There are sporadic outbreaks of D. setosum across the region. Studies conducted in Kenya

(McClanahan and Shafir, 1990) found similar results with high urchin abundance, specifically D.

setosum, and D. savignyi, on reef in the absence of finfish predators. Previous studies in this area

found very low numbers of D. setosum and some sites were free of D. setosum. Our results are

contradictory to this. all our sites are heavily dominated by D. setosum. A high abundance of sea

urchins on reefs can be productive for coral settlement as many sea urchins are herbivorous grazers,

removing algae from the reef, and simultaneously creating space for coral recruits to settle (Smith et

al. 2010). In a study conducted by Smith et al. (2010), the presence of herbivores was required for

coral settlement and while sea urchins contribute to algal grazing when herbivorous fish (Scaridae and

Acanthuridae) are removed, an overabundance of urchins may induce a phase shift to urchin

dominated reefs, which could alter the entire reef structure (Smith et al., 2010).

3.4 Mangrove Systems

3.4.1 Introduction

Mangrove ecosystems are found at the interface between land and sea. Mangroves typically grow in

tropical and sub-tropical latitudes and survive in extreme growth conditions with winds, high


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temperatures and muddy anaerobic soils which are flooded with incoming tides (Kathiresan and

Bingham, 2001). Although Madagascar has the highest surface area of mangroves in the Eastern

African region, only 9 of the 70 known mangrove species have been recorded here. The mangrove

systems around Ambalahonko contain 6 different species in four families: Rhizophora mucronata,

Ceriops tagal, Bruguiera gymnorrhiza, Avicennia marina, Sonneratia alba and Lumnitzera racemosa.

In Madagascar, mangroves are threatened by the development of urban areas, overfishing and erosion

caused by deforestation. Several mangrove areas have been converted to rice farming and shrimp

aquaculture which have an irreversible effect on the ecosystem. A loss of 3.6 million hectares of the

mangrove population since 1980 is estimated in Madagascar (Giri and Muhlhausen, 2008). The local

community has restricted the cutting of the mangrove trees around the village and started with the

restoration of the area by planting mangrove seeds. Due to physical and logistical difficulties not all

present mangrove species have successfully been replanted but Frontier will hopefully be able to help

with these restoration efforts. A functioning tree nursery in the Frontier basecamp, producing strong

and healthy mangrove seedlings, will provide us with a useful tool for future mangrove restoration

projects. In this preliminary study different methods and conditions to grow different species of

mangrove trees are investigated. The results will help us find the most feasible and effective

methodology which will be used in future restoration efforts. Successful mangrove nurseries prove to

be a great help for the reconstruction and conservation of mangrove forests. As the season for

flowering, fruiting and seed production not always overlay with the ideal planting season in the

degraded areas, nursery grown seedlings may provide a solution to avoid this mismatch (Ravishankar

and Ramasubramanian, 2004). The survival rate of nursery grown seedlings is higher than that of

naturally grown seedlings as their root systems are healthier and stronger.

3.4.2 Methodology

The tree nursery itself was modified to resemble the ideal growth conditions for mangrove trees. The

roof was made from coconut leaves which allowed some rainfall to come through but limited the

penetration of sunlight and thus mimicking the presence of tree canopy. The sides of the nursery were

covered with mosquito nets to regulate the shade. Soil for the mangrove seeds was collected from the

mangrove forest surrounding Ambalahonko and water bottles were used as flower pots to plant the

seeds. For this study seeds of three different mangrove species; Avicennia marina, Rhizophora

mucronata and Ceriops tagal were collected. All seeds were collected in the morning and taken from

the mother tree itself. Ripe seeds can be recognized by the yellow colouration of the cotyledon. All

the seeds were examined for incidence of diseases or pests. The R. mucronata and C. tagal seeds were

planted within the same day while the A. marina seeds were soaked in brackish water overnight. The


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soaking removes the seed coats and reduces the germination time by two to three days. After planting,

all the seeds were watered with a 70% fresh, 30% salt-water mixture.

To find the most suitable condition for the growth of mangrove seeds, different fertilizer types and

watering methods were used in this experiment. A total of 4 conditions were investigated. Ten seeds

of each of the three species were grown without fertilizer and watered every morning with a 70 %

fresh -, 30% salt-water solution as a control condition and to compare the success rate of the different

species. Ten C. tagal seeds, two R. mucronata seeds and one A. marina seed were used per different

conditions. In one of the conditions the seeds were not watered and thus only receive the water

entering the nursery through the coconut leaves. Adding dried, crushed banana peels to the soil

fertilized the second group of seeds. Potassium, the main nutrient found in banana peels, helps with

root development and promotes good water and nutrient flow in the plant. The third group of seeds

were fertilized, using crushed eggshells. Eggshells consist mainly of calcium, which is known to be

important for proper root and stem development. Calcium helps breaking down other nutrients in the

soil, such as nitrogen, which are vital for plant development. The last group of seeds was fertilized

with zebu manure. Manure contains the three main plant nutrients: nitrogen, phosphorus and

potassium. The manure also has large water content and is therefore beneficial as it keeps the soil

moist.

Frontier obtained permission from Didi, the president of Ambalahonko, to plant 70 individual

mangrove seedlings, Ceriops tagal, Avicennia marina and Rhizophora mucronata on 22/08/2017.

Five different sites were chosen close to Ambalahonko in accordance with the local community where

all sites have been subject to various levels of chopping. Five sites were chosen to compare the

success of the mangrove seedlings in different locations in relation to proximity to fresh and salt water

(Figure 9). A total of 6 staff members and volunteers, and 6 local people planted the mangrove

seedlings.


19

Figure 9 – Map showing the five replanting sites, close to Ambalahonko.

The 6-month-old seedlings were transported to the sites where 25 x 11cm holes were dug for each

individual. Seedlings were planted at least 30cm apart and species were divided evenly between the

sites, apart from site 4 where Ceriops tagal was the only species planted.

Figure 10 – Community member replanting a mangrove seedling.


20

East of Frontier camp, the first site is located across the river on the right, close to grass succession

approximately 25m from the river (Figure 11). The chosen site is surrounded by established adult

Ceriops tagal, with very few saplings and seedlings. This site is relatively sheltered from the wind

with very little canopy cover. The top 1.5cm of the sediment was mainly comprised of course grain

sand with slightly finer but still course organic rich sediment beneath. Marine fauna included small

mudskippers and very small fiddler crabs. Most of the individuals planted were close to the water line.

Figure 11 – Site 1, east of Frontier camp, across the river close to the grass succession.

Site 2 is located in the dense mangroves past the grass succession close to site 1 (Figure 12). This site

has Ceriops tagal, Bruguiera gymnorrhiza, Avicennia marina, Sonneratia alba, Rhizophora

mucronata and Lumincera racimora. This site is sheltered from the wind, with denser canopy cover

than site 1, with a break in the canopy around the site. The sediment is mainly course sand with a rich

layer of organic matter beneath. Marine fauna included very few fiddler crabs.


21

Figure 12 – Site 2, located in the dense mangrove behind the grass succession at site 1.

Site 3 is located at the back of the village, close to the Zebu field (Figure 13). The mangrove

community was dominated by Rhizophora mucronata adults, and Bruguiera gymnorrhiza and

Rhizophora mucronata seedlings. The site was surrounded by well-established Sonneratia alba adults.

The sediment is mainly comprised of course and fine sediment. This site is extremely sheltered from

the wind, with a break in the canopy. Marine fauna included bivalves and fiddler crabs. This site has

been subject to a lot of chopping in the past however there is no evidence of recent chopping.

Figure 13 – Site 3, located at the back of the village close to the Zebu field.


22

Site 4 is located at the back of the village, close to the community ‘toilet’ (Figure 14). A path used by

the local community divided the site which was waterlogged at low tide. This site was dominated by

all stages of Ceriops tagal, the sediment was mainly sand and less organic than the other 3 sites.

There are sporadic breaks in the canopy cover mainly above the path. This site had the least amount of

fiddler crabs.

Figure 14 – Site 4, located at the back of the village close to the community toilet.

Site 5 is located further down the path from site 4 and boarders the terrestrial forest (Figure 15). This

site is dominated by Ceriops tagal with some Avicennia marina. The sediment is mainly comprised of

course sand. This is the driest of the sites being the furthest away from the sea and river. This site had

many large crab holes with many small fiddler crabs.


23

Figure 15 – Site 5, located down the path close to the village toilet.

3.4.3 Results

At this point in the study, it is too early to draw any conclusion regarding the different conditions in

which the seeds are grown. This will be discussed later when more data is obtained and the study is

completed.

3.5 Marine Litter

3.5.1 Introduction

Pollution in the marine environment, especially plastic debris, has become ubiquitous in marine

environments and is a source of global concern due to the longevity and impact on marine organisms

(Derraik, 2002). An extensive review of published research has shown that between 60-80% of all

marine debris is plastic, and sources of plastic pollution are varied, but include equipment from

fishers/fishing fleets, other ship traffic (including container ships), deliberate littering or careless

handling of waste (Derraik, 2002). Proximity to industrialised areas, suburban areas and river mouths,

and our over-reliance on disposable products are also significant contributing factors to the amount of

marine debris observed in a given area (Derraik, 2002).

Collection of marine debris is one of the most effective ways to have a meaningful positive

environmental impact and to assess potential sources of environmental pollution so that management

strategies can be implemented that aim to curb input of non-biodegradable items. Frontier Madagascar

regularly undertakes beach cleans. The following is a summary of items collected, a discussion of


24

potential sources of marine debris and suggestions for management strategies that may reduce the

amount of marine debris in the areas surrounding Ambalahonko.

3.5.2 Methodology Beach cleans were typically undertaken twice per week, approximately one hour either side of low

tide. Volunteers and staff would venture to the right of camp, passing Ambalahonko village and a

small stream, or left to Black Rocks, collecting debris as they go between the water and tree line. For

each piece of litter, the type and zone (sand, mangrove, tree line) in which it was collected was

recorded. Upon collection, debris was sorted into flammable and non-flammable items for burning, or

storage respectively.

3.5.3 Results During Phase 173, a total of 4253 pieces of marine debris were collected from sand, mangrove and

tree areas along the coastline proximal to Ambalahonko Base Camp. During phase 172, only 3341

pieces of marine debris were collected. Plastic (unidentifiable plastic objects, plastic bottles and

plastic bags) accounted for 46% of the total amount of debris found (Fig. 16). Along the left-hand side

of the beach plastic accounted for more than 59% of total debris (Fig. 17). The amount of litter was

similar on the left-hand side and the right-hand side however there were some significant differences

in type of litter. For instance, only 2 batteries were found on the left-hand side, with 119 on the right-

hand side, this is most likely due to the presence of Ambalahonko on the right-hand side (Figure 18).

Figure 16 – Composition of marine litter collected along the entire beach during phase 173.

3% 4%

46%

4%

1%

2% 1%

6% 2%

7%

8%

1%

3% 0%

1% 1% 0%

3%

6%

0% 0%

Little Collected Along Entire Beach Plastic Bag Plastic Bottle Plastic Other Sweet Wrappers Rice Bag Fishing Line/rope Lobster Pot Metal Shoes Fabric/Clothing Glass China/Crockery Batteries Mosquito Net Eletricals Nappies Lighters


25

Figure 17 – Composition of marine litter collected along the left-hand side of the beach during phase

173.

Figure 18 - Composition of marine litter collected along the right-hand side of the beach during phase

173.

5% 4%

59%

5%

2%

2% 0%

5%

2% 4%

4% 0%

0%

0% 0% 1% 0%

4% 2%

0% 0% Litter Collected From Beach Left

Plastic Bag Plastic Bottle Plastic Other Sweet Wrappers Rice Bag Fishing Line/rope Lobster Pot Metal Shoes Fabric/Clothing Glass China/Crockery Batteries Mosquito Net Eletricals Nappies Lighters Polystrene Paper/cardboard Cigarette pack Other

2%

4%

34%

4%

1%

3%

2%

7% 1%

10%

11%

2%

5% 0%

1% 1% 0%

1%

9%

0% 0% Litter Collected From Beach Right

Plastic Bag Plastic Bottle Plastic Other Sweet Wrappers Rice Bag Fishing Line/rope Lobster Pot Metal Shoes Fabric/Clothing Glass China/Crockery Batteries Mosquito Net Eletricals Nappies Lighters Polystrene Paper/cardboard Cigarette pack Other


26

3.5.4 Discussion Consistent with previously published works, plastic items were the most common type of debris

collected, and many were smaller fragments of unidentifiable origin and unknown age (Santos et al.,

2008). The higher amount of certain debris types collected on the right side of camp can be explained

by the location of the Ambalahonko village. Beach cleans on the right side include the beach area in

front of the village; this is also the area where the highest amount of debris was collected.

There is a lack of education about the impacts of anthropogenic litter on the marine environment, a

lack of litter collection and processing facilities, and a current lack of alternatives to the use of single

use plastics. The introduction of Environmental Awareness Days, of environmentally safe waste

disposal systems, the involvement of local communities in beach cleans, and a discussion about

possible alternatives to the use of plastic products would be an excellent starting point for raising

awareness and eventually reducing marine pollution.

For the longer term, like most countries, a general move away from reliance on single use plastic

items is essential. This also holds true for batteries which were frequently collected and are especially

toxic. The distribution of battery collection strongly shows that they come from local use and are less

likely to be brought in with the tide. Some progress could be made to reduce battery waste if funding

was available to buy small solar panels that could then in turn charge reusable batteries.

3.6 Nudibranch Survey

3.6.1 Introduction

Nudibranchs are an order (Nudibranchia) of Opithobranch Gastropods and are one of the most diverse

and charismatic groups of tropical marine molluscs. Ecological knowledge of nudibranch species and

specifically data concerning their diversity, abundance, distribution and behaviour is very limited.

Studies into their phylogeny are exceedingly important to northern Madagascar, which is increasingly

becoming recognised as a biological hotspot with high amounts of biodiversity. Nudibranchs have low

fecundity and low dispersion rates, meaning as a group of species they are not very resilient. Research

into their ecology is needed for specific conservation efforts to be made.

The aim of the nudibranch survey is to investigate the abundance and diversity of nudibranchs in the

area and consequently to compare the results to previous research. Additionally, nudibranch surveys

can provide data to create a nudibranch species catalogue of Nosy Be.


27

3.6.2 Methodology

The surveys were conducted at our survey sites and additional sites located in the Nosy Vorona Bight.

At least two nudibranch surveys are conducted per week, for 30-40 minutes. The roving diving

technique is applied (Munro, 2005), covering an area as large as possible at 0-18m. Once nudibranchs

were spotted, photos were taken in situ. In addition, size (to the nearest mm), substrate and depth of

the individuals were noted.

3.6.3 Results

The abundance and diversity of nudibranch were studied over a 1-month period, which is the start of a

long-term dataset. A total of 80 nudibranch individuals, belonging to at least 14 different species, were

surveyed (Figure 19; Table 5). The largest group was Doridina, followed by the suborder Aaolidina.

The average amount of nudibranchs was highest at Nosy Vorona and the lowest at Blue Pillars (26 and

2, respectively).

Figure 19 – Average number of nudibranchs at our survey sites.

0

5

10

15

20

25

30

Area 51 Nosy Vorona Turtle Towers Saturday Blue Pillars Black Rocks

Ave

rage

Nu

mb

er

of

Ind

ivid

ual

s

Nudibranch Abundance


28

Table 5. Identified nudibranch species

3.6.4 Discussion

As the survey has only been taking place for 1 month, there is very limited data. With additional data

we can investigate relationships with depth and preferred substrate. The list of species is considerably

small potentially because various species of nudibranchs are small, camouflaged or just rare (Jensen,

2007). Furthermore, species may be difficult to find because they have a cryptic lifestyle or a short-

life history (Clark, 1975). Due to the small amount of nudibranch surveys, coupled with life-style and

life history, it is likely that the present number of nudibranchs is an underestimation and that

additional species will be discovered.

3.7 Research Projects

A Preliminary Assessment of Small Scale Fishing Activity in Nosy Be, Madagascar.

Author: Ella Garrud

3.7.1 Introduction

Madagascar is the fourth largest island and the fifth poorest maritime country in the world, with

approximately 75% of all households living below the poverty threshold (Le Manach et al. 2012;

Barnes-Mouthe et al. 2013). Many of the people rely heavily on the ocean to survive, using marine

resources both as a source of food and income, particularly in coastal communities (Le Manach et al.

2012). Over 50% of the population of Madagascar live by the coast and up to 87% of adults in some

coastal communities are employed by the small-scale fisheries sector (Barnes-Mouthe et al. 2013).

There is currently very limited information on the extent of the small-scale fisheries sector in

Madagascar (Barnes-Mouthe et al. 2013). In the Madagascan government, the Ministry of Fisheries

and Aquatic Resources is responsible for all fisheries, and other Government bodies are responsible

Moridilla brockii

Hypselodoris pulchella

Phyllidia varicosa

Marionia levis

Phyllidiella meandrina

Phyllidiella zeylanica

Phyllidia coelestis

Taringa caudata

Phyllidiella pustulosa

Chelidonura varians

Chromodoris africana

Risbecia imperialis

Chromodoris annulata

Phyllidiopsis annae


29

for related activities, such as environmental regulation and planning of marine protected areas. These

sectors are chronically underfunded and understaffed. There is currently no official document that

states the Government's fisheries policy and any legal framework that does exist is incoherent and

ambiguous. Consequently, small scale fisheries catches are often underestimated when being reported

to official agencies, such as the Food and Agricultural Organization (FAO) of the United Nations, or

remain completely unreported (Le Manach et al. 2011). Illegal, unreported and unregulated fishing

(IUU) is known to be a major impediment towards sustainable fisheries management worldwide

because the sustainability of fisheries is overestimated due to incomplete data (Sumaila et al. 2006).

Le Manach et al. (2011) reconstructed the catch data reported to the FAO by the Government of

Madagascar and found that the estimated reconstructed total is twice as high as the official reported

data. This can partly be attributed to the data that is unreported and underestimated by the small-scale

fisheries sector (Pauly et al. 1997; Le Manach et al. 2011). There has currently been no research into

the fisheries around the island of Nosy Be, Madagascar. The purpose of this study is to make a

preliminary assessment of the fishing activities in the southeast area of the island with a particular

focus on small scale fisheries. The aims of this study are to investigate what species of fish are being

caught, the volume of fish being landed, the areas in which people fish, what gear is being used, how

much fish is sold for in the local markets in Hellville, whether certain species are being targeted and

whether any bycatch occurs. From this, it will hopefully be possible to estimate a catch per unit effort

for the different gears being used and species being caught.

3.7.2 Methodology

The proposed aims will be achieved by a number of different methods. Firstly, the researcher will

conduct informal interviews with a local artisanal fisherman and accompany them on their pirogue on

fishing trips to obtain a better understanding of fishing methods that are being used in the area.

Secondly, after this initial stage, questionnaires will be used to gather data from at least 30 local

small-scale fishers on what species they catch, whether certain species are being targeted, where they

fish and what species they catch in each area, what gear they use and whether they catch any bycatch.

Thirdly, the researcher will make visits to the local fish markets in Hellville. Using photography

analysis as the main method, the variables that will be collected are the species being sold, the average

price for each species, and the number and size of the fish being sold.

3.7.3 Potential Outcomes

If this research is successful it will give an insight into the fishing activities of the southeast area of

Nosy Be. The methods of this study could be used to collect data on the small-scale fisheries of other

areas of Nosy Be and mainland Madagascar. The results of this study can potentially be used to


30

implement sustainable fisheries policies for the area with the help of the people in the village of

Ambalahonko.

4. Proposed Work Programme for Next Phase

1. Continue long-term biomonitoring of the coral reefs in the area.

2. Monitor the mangrove seedlings at the replanting sites.

3. Continue assessment of Small Scale Fishing Activity in Nosy Be.

4. Continue our nudibranch surveys, assessing abundance and diversity in the area.

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