Madagascar Marine Conservation Research

Programme

Nosy Be, Madagascar

Kimberly Rogan, Antoine de Clippele, Francesca Batt

September 2018 - December 2018

Field Staff

Staff Member RoleKimberly Rogan (KR) Principal Investigator (PI)Awena Sangster (AS) Dive Officer (DO)David Best (DB) Project Coordinator (PC)/Dive Officer (DO)Emma Rolls (ER) Assistant Research Officer (ARO)Antoine de Clippele (AD) Assistant Research Officer (ARO)Francesca Batt (FB) Assistant Research Officer (ARO)Liam Ward (LW) Assistant Research Officer (ARO)Victor Tomboravo (VT) Local Staff (LS)

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Contents

1 Introduction 31.1 Frontier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Aims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3 Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Training 42.1 Briefing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.2 Science Lectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42.3 Practical Instruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.4 Dive Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Research Program 63.1 Biological Monitoring of Coral Reefs in the Nosy Vorona Passage . . . . . . . . . . . . . . 6

3.1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63.1.2 Survey Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73.1.3 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93.1.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113.1.5 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.2 Marine Litter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.2.2 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.2.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173.2.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3 Hawksbill Turtle Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.3.2 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

3.4 Proposed Research Plan for Phase 191 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

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1 Introduction

1.1 Frontier

Madagascar, the world’s fourth largest island, is located in the southwest Indian Ocean, 440km off theeastern coast of Africa and across the Mozambique Channel (Jadot, Darling, and Brenier 2015). Theisland boasts over 5,000km of coastline with a coral reef system that extends approximately 3,540km(Cooke et al. 2000). Madagascar has the highest coral diversity in the Western Indian Ocean (WIO)region and reef fish diversity in the northwest region, comprising of approximately 576 species (McKennaand Allen 2003). Madagascar is considered to be one of the world’s most important biodiversity hotspotsand it is crucial that it becomes a priority for conservation efforts as the endemism and diversity areunder threat by human impact (Goodman and Benstead 2005).Madagascar has various fisheries, which include traditional small-scale fisheries, where fishermen usewooden boats known as pirogues, to an industrial fleet that focuses on deep-sea and shrimp fishing(Jadot, Darling, and Brenier 2015). Small-scale fishing target reef fish and invertebrates, which accountsfor the majority of the annual catch estimate of 130,000 tons. Although certain species such as snappersand groupers are preferred, very few are considered inedible and therefore still fished from the reefs(Jadot, Darling, and Brenier 2015). Targeting larger, predatory species can eventually lead to what iscalled a trophic cascade, which abundance of prey increases and reduces quality of primary production(Wilson et al. 2010). Fisheries in Madagascar are poorly managed with the actual catch being under-reported by up to 500% in past years (Le Manach et al. 2012). Although the gap between reported catchand actual catch is decreasing, there is still approximately 40% under-reported catch occurring each year(Le Manach et al. 2012). A large percentage of the population in Madagascar rely on small-scale fishingas their base income, which makes the issue of heavily overfishing coral reefs a serious issue for marineecosystems and future food security (Le Manach et al. 2012).Coral reefs are delicate and complex ecosystems that are susceptible to natural and anthropogenic distur-bances, which increase the risk of habitat loss for marine organisms (Wilson et al. 2001). The majorityof coral reef fish have close associations with coral reefs and some are even highly dependent on thebenthic substrate (Wilson et al. 2001). Previous studies have indicated that coral reef fish assemblageshave exhibited signs of a change in structure, which is causing a loss in biodiversity (Feary et al. 2007).The shift in fish communities highly suggests that there is a high reliance on coral reef habitat and adultfish population dynamics may be strongly affected by habitat recruitment. For example, although acertain fish species may not typically be associated with branching corals, they may begin to inhabitsuch areas if necessary (Feary et al. 2007). A serious long-term ecological impact of phase-shifts in coralreef environments includes the loss of invertebrate and fish species, and coral diversity (Jackson et al.2001).Measures of species diversity and endemism are two crucial components in determining global conser-vation efforts (Goodman and Benstead 2005). Understanding the health of Madagascar’s reefs and theeffects of human and environmental impacts on reef ecosystems is essential. The limited body of environ-mental research of marine organisms inhabiting Madagascar’s waters is insufficient to estimate speciesrichness, therefore it is important to continue research on the state of the coral reefs in the Nosy VoronaPassage (Goodman and Benstead 2005). Currently, there are only two Marine Protected Areas (MPAs)in Madagascar and multiple Locally Managed Marine Areas (LMMAs), but only 2% of the coral reefsin Madagascar are located within those protected zones and the majority of fisheries are regarded asunsustainable (Goodman and Benstead 2005).Frontier Madagascar has been monitoring sites in Northwest Madagascar since 2010. Operating fromthe village of Ambalahonko, Nosy Be, it uses trained staff members and volunteers to collect data on themarine fauna surrounding the Nosy Vorona Passage. This report discusses the research and conservationwork undertaken by the Marine Conservation Research Team from September to December 2018.

1.2 Aims

The general aims of the Frontier Madagascar Marine Conservation Research Program are to research thehealth of the coral reef ecosystems in the Nosy Vorona Passage and to train volunteers and staff in thescientific methods necessary to conduct surveys. Surveys on reef biodiversity include fish and invertebrateabundance, and benthic composition. Turtle surveys are also conducted at three sites to evaluate sexratios in the region. As the state of the reefs is better understood, measures can be recommendedand conservations can be enacted. Regular beach cleans are also completed to document environmentalpollution and to implement management strategies for proper litter disposal.

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1.3 Objectives

There are various objectives, which must be completed to investigate the broad aims of the project:

Objective 1: To assess reef fish communities using underwater visual consensus (UVC) to build upona long-term dataset of fish assemblages.

Objective 2: To assess the state of invertebrate species using UVC surveys and to build upon along-term data set of invertebrate abundance and diversity.

Objective 3: To monitor the benthic community composition using line intercept transects to use asa long-term data set.

Objective 4: To evaluate the sex ratios of Eretmochelys imbricata (hawksbill turtles) and create acatalogue of individuals in the Nosy Vorona Passage.

Objective 5: To assess the marine litter collected along the beach and in the mangroves near FrontierMadagascar Camp and to enact measures to reduce the quantity of litter.

2 Training

2.1 Briefing

Initial presentations on camp logistics, health and safety, dive operations, and the MGM project weredelivered within the first week of the volunteers arriving on camp (table 1).

Table 1: Briefing sessions for new staff and volunteers conducted during Phase 183.

2.2 Science Lectures

A number of lectures were given and documentaries shown throughout phase 184 (table 2). Lecturesand quizzes/tests used in previous phases were updated and new lectures were created to aid in learning.Conservation documentaries were also shown on occasion during this phase to encourage discussionamongst volunteers.

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Table 2: Lectures and documentaries shown to volunteers during Phase 184.

2.3 Practical Instruction

After introductory lectures and required dive training, in-water training for survey techniques and speciesidentification begins. Identification for fish and invertebrate species, and benthic compositions are prac-ticed using flash cards. After revision, standard computer quizzes (20 questions) and tests (30 questions)are given. Once they are passed, an in-water test takes place with a member of staff. All tests have apass mark of 95% and once passed the volunteer may take part in surveying.

2.4 Dive Training

Volunteers must be qualified as PADI Advanced Open Water or higher to participate in surveys. Pleasesee the dive report for all dive training undertaken during this phase.

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3 Research Program

3.1 Biological Monitoring of Coral Reefs in the Nosy Vorona Passage

3.1.1 Introduction

Coral reefs around the world are being threatened by anthropogenic disturbances such as climate changeand pollution. Approximately 30% of coral reefs have already suffered detrimental effects and by 2030it is predicted that up to 60% of coral reefs may be lost (Hughes et al. 2003). Despite their importance,between 50 - 70% of all coral reefs are still under threat from anthropogenic pressures such as coral bleach-ing, rise in sea temperatures, overfishing, and damage from boat/fishing equipment. (Hoegh-Guldberget al. 1990; Goreau 1992; Sebens 1994; Wilkinson and Buddemeier 1994). Since the pre-industrial era,surface air and sea surface temperatures have risen approximately 1oC. This raise in temperature ishuman induced and expected to reach 1.5oC in the near future. The rapid warming causes an extremeamount of stress on coral reefs and marine organisms, which causes a habitat range shift for most or-ganisms (Hoffman and Parsons 1997; Woodward 1987). Sessile organisms, such as corals, are unable torelocate to more suitable conditions and are therefore left to suffer the consequences of a rapidly changingenvironment. Although coral reefs only cover about 0.5 – 1% of the world’s oceans, they form the mostdiverse and productive ecosystems in the ocean (McAllister 1991). It is estimated that 25% of all marinefish inhabit coral reefs and are therefore highly dependent on the benthos for survival (Dubinsky 1990;McAllister 1991). Conservation efforts are therefore vital to preserve existing coral species for the manyservices they provide in the face of such rapid environmental change and severe anthropogenic influences.Not only do coral reefs provide habitat for thousands of marine species, they contribute millions of dollarseach year to ecotourism through snorkeling and diving (Spalding et al. 2017).Population dynamics is an important branch of ecology for coral reefs that includes the study of shortand long-term changes in a given population’s size, structure and age distribution (Chadwick-Furman,Goffredo, and Lova 2000). Within population dynamics, many aspects can effect a population causing achange in one or more of these factors . These effects may be biotic such as predation and competitionor abiotic such as temperature, nutrient availability or wave action (Chadwick-Furman, Goffredo, andLova 2000). Populations therefore, are studied as dynamic systems, changing in size and structure overtime. By studying a population, an understanding of the ecological drivers behind the population canbe established. This information is useful when assessing the vulnerability of a population to bioticand abiotic effects, as well as the long-term sustainability while under environmental stress (Verburget al. 2002). Studies of population structures are usually completed over several years to establish anestimate of a species’ survivability and productivity for future growth (Kenkel, Hendrie, and Bella 2009;“Is climate change affecting the population dynamics of the endangered Pacific loggerhead sea turtle”).Constant monitoring and surveillance of populations is becoming increasingly important to ensure thesafety of a species when under external pressures such as anthropogenic induced climate change andpollution (Walther et al. 2002; Haward 2018; Mangrove Management, Assessment and Monitoring).The populations in marine ecosystems, like coral reefs, need to be monitored due to their complex com-munities. Marine fish and invertebrate species play an essential role in food webs and nutrient cycling(McClanahan et al. 1999). In particular, marine macro invertebrates contribute to bioturbation and bio-erosion of coral reefs, assisting in coral settlement (McClanahan et al. 1999). Bioturbation is a processin which sediments are reworked by animals or plants while bioerosion is the breakdown of hard oceansubstrates (“Coral reefs in the Anthropocene” 2015). Some macro invertebrates that contribute to bio-turbation are sea cucumbers as they defecate sediment grains. Molluscs such as clams contribute a largepercentage to bioerosion as they burrow into corals (Shelley et al. 1988). A rise in ocean temperaturescombined with a higher ocean acidification and an increased amount of dissolved inorganic carbon willprevent the growth of some invertebrates (Caldeira and Wickett 2003). The loss of invertebrate species,greatly reduces bioturbation on benthic substrates, causing a total loss of functionality of the ecosystem(Solan et al. 2004).Other anthropogenic pressures can also affect the functionality of the coral reef. For example, our re-liance on fisheries for food and resources places a strain on marine populations that live in areas suchas Madagascar. This increased fishing pressure paired with other abiotic effects places marine species’populations at a higher risk of decline or extinction, with unregulated commercial fishing already causinga decrease in marine populations off the coast of Madagascar (Le Manach et al. 2012). A stable fishpopulation is vital to maintain for both human livelihoods and to maximize ecosystem functionalitythroughout coral reefs (Moberg and Folke 1999).In the present study, populations of reef fish, invertebrates, and benthic compositions are monitored to

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assess population’s long-term viability as well as resistance and resilience to increasing anthropogeniceffects. This study aims to provide evidence of a decline in marine biodiversity in the Nosy VoronaPassage due to unsustainable anthropogenic activity and recommendations for sustainable managementof the marine environment. The nature of the study enables continuous data collection for long termstudies to determine and monitor reef health.

3.1.2 Survey Sites

During Phase 184, fish, invertebrate, and benthic composition were sampled at four sites in the NosyVorona Passage, Nosy Be, NW Madagascar (figures 1 and 2). This area is surrounded by the fishingvillages of Ambalahonko (pop. 100) and Antafondro (pop. 100), which are approximately 8km east ofHell-Ville. The area is characterized by fringing patch reefs and shallow continentalshelf waters withdepths reaching no more than 20m.

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Figure 1: (Top) The island of Nosy Be, located Northwest of Mainland Madagascar. (Bottom)The four survey sites in the Nosy Vorona Passage

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Table 3: Description of the study sites surveyed in Phase 184. Temperature ranges for allsites are between 27o − 31oC

3.1.3 Methodology

Underwater visual consensus (UVC) surveys were conducted using SCUBA by qualified staff and volun-teers (Samiolys and Carlos 2000). A minimum of three divers were necessary to complete a full survey,providing an estimation or relative abundance, biomass of reef species. The roles involved different sur-veyors focused on schooling fish, territorial fish, invertebrates, and benthic (table 4). Transects were atotal of 80m and divided into 20m sections with a 10m redundant area to reduce duplicate counts of fish(0-20m, 30-50m, 60-80m) (figure 2). Transects were placed randomly on the reef boundary for fringingreefs and across the reef for patch reefs. There are limitations through potential repetition of transectsections. Random transects allow you to get a broader understanding of the different species and benthiccompositions of the entire reef rather than focusing on a specific location of the reef (Edgar and Barrett1999). To ensure randomization, divers would snorkel towards the reef then descend once a part of thereef began. Schooling and territorial fish surveyors count the number of fish within a 5x5m box and totalthe number of species for the 60m transect. Invertebrate surveyors swim in a zigzag pattern along thetransect searching for invertebrates and total the number of individuals. The benthic surveyor swimsalong the transect line recording composition including hard corals, soft coral, sponges, sand, rock, coralrubble, algae, hydroids, and zoanthids. The length of each category under the transect line is recorded.For the statistical analysis, a Shapiro – Wilk normality test and a Bartlett test of homogeneity of vari-ances was used for fish and invertebrate data. All statistics tests were run using Rstudio version 1.1.456(RCoreTeam 2018) at a 95% confidence interval.

Figure 2: Procedure for UVC surveys of a 20m section of the transect. The surveyr recordsall fish observed in the box. The invertebrate surveyor will follow a similar procedure, exceptswim in a zigzag formation to 2.5 meters on each side of the transect.

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Table 4: The roles and responsibilities for each diver taking part in BSP surveying. Categorieswere split into schooling and territorial fish to make studying and surveying easier for divers

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3.1.4 Results

Assessment of Reef Fish Abundance and Diversity in Nosy Vorona Passage

There were a total of three surveys at Home Reef, nine at Vorona, eight at Three Brothers, and seven atArea 51 for Phase 184. Vorona had the highest abundance of reef fish (5401 individuals) in comparisonto the other three sites, however that site had the most surveys. Three Brothers had one more surveythan Area 51 but had a lower abundance (2255 individuals) than Area 51 (2672). Due to some misplaceddata, Home Reef only had three surveys and therefore an abundance of 1424, which is much lower thanthe other sites. The average number of individuals at each site per survey was Home Reef (475), Vorona(600), Three Brothers (282), and Area 51 (382). Although Home Reef had fewest surveys, it still had ahigher overall average of individuals per survey than Three Brothers and Area 51 (figure 3). There wasno significant statistical difference of fish abundance across sites (P = 0.275).

Figure 3: The number of individual reef fish per site. Vorona had the highest abundance of fish(5401) over 9 surveys. Area 51 had the second highest abundance (2672) and Three Brothershad an abundance of 2255. There were only 3 surveys at Home Reef, which only had 1424individuals.

Although there were fewer surveys at Home Reef, the average species richness was only slightly lowerthan Three Brothers with 17 and 19 species respectively. Vorona still had the highest average richness(32) and Area 51 had an average of 25 species per survey (figure 4). Tukey’s multiple comparison testshowed that Vorona was statistically different from the other sites except for Area 51. The overall speciesrichness across each site however, was not statistically significant (P = 0.158). Bartlett’s statistical testshowed a nearly significant result (P = 0.055) that was to determine if the higher number of species ata site is due to a higher number of fish.

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Figure 4: The average number of species per site. Vorona had the highest average speciesrichness (32) over nine surveys. Area 51 had a slightly higher species richness (25) than ThreeBrothers (19). Home Reef only had 3 surveys and had the lowest diversity of 17 species.

Assessment of Invertebrate Abundance and Diversity in Nosy Vorona Passage

During Phase 184, there were four invertebrate surveys at Home Reef, eight at both Vorona and ThreeBrothers, and seven at Area 51. The highest overall invertebrate abundance was at Vorona (4399). Area51 had the second highest overall abundance (3709) followed by Three Brothers (2389). Home Reef hadthe lowest abundance with 1485 individuals but had the second highest average number of individualsper survey (223). There was an average of 305 individuals per survey at Area 51. Vorona and ThreeBrothers had a much lower average per survey with 58 and 56 individuals, respectively. There was nostatistical difference in the overall abundance of invertebrates across each site (P = 0.096). However,Bartlett’s test showed that Home Reef and Area 51 were statistically different from Three Brothers andVorona.The sea urchin, Diadema setosum, is included in the overall abundance, however they were also shownseparately as in some sites they are in incredibly high abundance in comparison to the other inverte-brate species (figure 5). At Vorona there was a total of 3939 D. setosum, which was 90% of the totaloverall invertebrate abundance. Three Brothers had the second highest abundance (1944) of the seaurchin and it made up 81% of the overall abundance. At Area 51, there was a higher abundance of allother invertebrate species (2135) than D. setosum (1574). About 42% of the invertebrates counted atArea 51 were D. setosum. Although there were only three surveys at Home Reef, it had the fewest D.setosum (593). Only 40% of the total number of invertebrates at Home Reef was D. setosum. Tukey’smultiple comparison test showed that Vorona differed significantly from the other three sites in terms ofD. setosum abundance. The proportion of D. setosum versus invertebrates was statistically significantat Vorona than at the other sites (P = 0.009).

There was no statistical significance of invertebrate species richness across each site (P = 0.117)(figure 6). All sites had a similar average with Area 51 having the highest average of 8.29 species.Vorona had the second highest richness (7.63) and although Home Reef had fewer surveys than the othersites, the average amount of invertebrate species was slightly higher than at Three Brothers with 6.75and 6.25 species respectively.

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Figure 5: The total number of individual invertebrate species and D. setosum at each site.Vorona had the highest overall abundance (4399 individuals). Home Reef had the lowest abun-dance (1485) and the fewest D. setosum (593). Area 51 had the second highest overall abundance(3709) and fewer D. setosum (1574) than at Three Brothers, which had an invertebrate speciesabundance of 445 and 1944 total D. setosum.

Figure 6: Average invertebrate species richness at each site. The averages across the siteswere quite similar with Area 51 having the highest diversity and Three Brothers with the lowest.

Documentation of Benthic Morphology in Nosy Vorona Passage

At each site, the living benthic percentage cover was divided into hard coral, soft coral, sponge, al-gae, hydroids, anemones, and zoanthids. A significant difference between sites was found between softcoral and sponge percentage cover. Area 51 shows a higher percentage cover at 8.2% soft coral against1.7% in Nosy Vorona (P = 0.016). In addition, regarding the sponge coverage, Area 51 also shows ahigher percentage (10.2%) than any other sites (P = 0.021; 0.003 and 0.008). There was no significantdifference between sites for hard coral, rubble, and algae coverage. As figure 7 shows, sand and hardcoral formations had the highest overall percent coverage at each site.

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Figure 7: The percent coverage of benthic morphology across each site. Sand, hard coral, andcoral rubble were amongst the highest compositions.

3.1.5 Discussion

Fish and invertebrate community structures, and benthic composition in a coral reef ecosystem can actas an indicator of overall reef health. Overall, Home Reef had the lowest fish and invertebrate abundanceand average species richness. A large percentage of benthic composition at Home Reef consisted of sand,algae, or coral rubble, which are not ideal habitats for reef fish. There was also no sponge at this site,which can provide habitat for invertebrates such as nudibranchs. Area 51 has the highest invertebrateabundance and lowest D. setosum abundance (excluding Home Reef). The 10% sponge cover at Area51 could contribute to the higher number of invertebrate species. Nosy Vorona had the highest fishabundance and average species richness but quite low invertebrate species abundance in comparison tothe abundance of D. setosum. Studies indicate that the presence of D. setosum on coral reefs at highabundance with low predation results in the reef becoming barren, the echinoid was most abundant atVorona despite the high quantity of fish species and families present (Larsson, Henriksson, and Grahn2010). This could be due to the high percentage of sand and coral rubble/rock cover, which can indicatethat the health of Vorona’s reef may already be in decline. All sites were fairly similar when comparingaverage invertebrate species richness, as the most common species found at each site were the echinoidP.gratiosa, holothuroids H. atra, and H. edulis, bivalves, and nudibranchs.Overall, the coral reefs Frontier survey are showing some signs of overfishing, which includes lack oflarger predatory fish species such as parrotfish and triggerfish, high sea urchin populations, and deadcoral patches. This becomes a major stressor on the reefs as loss of predators can cause inter- and intra-specific competitive interactions, such as sea urchin populations, in this case D. setosum, dominatingcoral reefs (Larsson, Henriksson, and Grahn 2010). This study has shown that when sea urchin predatorsshow signs of decreasing populations, it gives an opportunity for sea urchin grazers to increase greatly innumbers. When sea urchin populations become too high they create areas known as “urchin barrens”,which happens when they remove quantities of living and dead coral (Larsson, Henriksson, and Grahn2010). As the data shows from this phase, D. setosum abundance is significant in comparison to otherinvertebrate species at each site. Figure 8 gives an example of a sea urchin barren at Vorona. There arecurrently two strategies that have been put into use globally to help prevent coral reefs from suffering theconsequences of urchin barrens. The first is to alleviate fishing pressures from the reefs to allow for seaurchin predators to increase their population numbers (Wilson et al. 2010). The other is called the “SeaUrchin Reduction” method, which requires sea urchins to be removed by hand (Larsson, Henriksson, and

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Grahn 2010). For this, divers use a knife to quickly kill the urchin and it is removed from the reef. It is arelatively safe method if divers receive proper training. While sea urchin reduction removes the problemimmediately, it does not solve the issue of creating a long-term healthy ecosystem. For conservationpurposes, managing fishing practices would be the most beneficial to the overall health of the reefs.Biological monitoring of coral reefs is vital now more than ever to understand any patterns or changesin the marine ecosystem. With climate change and overfishing as serious threats to the health of reefsglobally, continuous studies of fish assemblages, invertebrate abundance and diversity, and benthic com-position are essential in implementing conservation and management strategies. This project will addressthese concerns, following on from previous phases, ensuring continuous coral reef monitoring.

Figure 8: An example of a sea urchin barren found at Vorona on one of Frontier’s surveys.

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3.2 Marine Litter

3.2.1 Introduction

Over the past 50 years pollution in marine environments, particularly plastics, has become an increasingconcern due to the longevity and impact on marine organisms and coral reefs (Derraik 2002). Plasticscontribute 60-80% of all marine debris with equipment from fishing, ship traffic, deliberate littering, orcareless handling of waste being top contributors (Derraik 2002). Plastic bags, synthetic rope, fishingnets, and other plastic materials may last up to decades in the ocean and although they are typicallylightweight and buoyant, they can end up on the seabed and become ingested or entangle wildlife (“Per-sistent plastics and debris in the ocean: an international problem of ocean disposal”). Plastic debriscan persist in the marine environment for over 450 years due to the degradation rates of plastics (Vinceand Stoett 2018). Theses plastic fragments can leach toxins into the environment. This debris thereforehas the potential to impact all trophic levels of the marine environment, in particular coral reef habitats(Allen, Seymour, and Rittschof 2017). Litter also washes up on beaches, making shorelines aestheti-cally unappealing and reducing the value of these resources from a recreational perspective (“Cleaningbeaches: sweeping the rubbish under the carpet”). In villages such as Ambalahonko, deliberate litteringtypically ends up in the surrounding mangroves and in the nearby reefs (Rogan, Jones, and Bennett2018).Beach cleans are effective ways to have a positive impact on the immediate environment and to assesspotential sources of pollution, so management efforts can be implemented to ensure the proper disposal ofnon-biodegradable litter. With the knowledge Frontier obtains from conducting beach cleans, efforts canbe made to ensure proper disposal of biodegradable and non-biodegradable litter as well as communityinvolvement to educate about the threats of litter in the ocean, especially with mangroves and coral reefsbeing major ecosystems for the village of Ambalahonko. This studies future aims would be to promotelocal litter management improvements, therefore, reducing pollution and other negative impacts on themarine environment.

3.2.2 Methodology

Beach cleans were typically completed twice per week, with one on each the right and left side of theFrontier camp (figure 9). Cleans usually lasted about 30 to 45 minutes. Staff and volunteers split to theright of camp, past Ambalahonko (village transect, approx. 200m) or to the left of camp (control transect,approx. 500m). The control transect is not in close proximity to the village and so the litter collectedhere is not likely to be from the villagers but from marine litter washed up from tides. Limitations ofthis study would be that the control site is used as a pathway between villages and as such, may alsobe impacted by anthropogenic factors. All litter was collected between the mangrove roots and the treeline. For each piece of litter, the type and zone (mangrove roots, sand/rocks, and trees) in which itwas collected was recorded. Upon collection, litter was sorted into burnable and non-burnable bags todispose of properly after the beach cleans. Unfortunately, there is no “green” way of disposing rubbish,so plastics, fabrics, papers, and materials that can be burned are all taken to the burn pit on camp, whichis the method local villages use. Metals, glass, and electronics (non-burnables) were kept separately andtaken into a facility in Hell-Ville. Plastic bottles were stored on camp for the potential of reusing forother projects.

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Figure 9: AVillage (red) and Control (yellow) transect locations. Frontier base camp is locatedbetween the two transects. The village transect was approximately 200m in length, falling directlyadjacent Ambalahonko village and the control transect was the stretch with no direct link to eitherAmbalahonko village to the west or Antafondro village to the east.

3.2.3 Results

There were 20 beach cleans (11 village, 9 control) during Phase 184. In total, 1185 pieces of litter werecollected on the village transect while only 565 pieces were collected on the control transect. Of the piecescollected on the village transect, 808 pieces were burnables and 377 were non-burnables (figure 10). Onthe control transect, 502 pieces were burnable and 63 were non-burnable. The burnables on the villagetransect contained 44% plastic products such as plastic bags, plastic bottles/caps, hard plastics, and softplastics. However, the control side had a higher percentage of plastic products (56%). Other commonfindings were shoes, fabrics/clothing, food wrappers, and washing up packets. Most of the non-burnablescollected were shards of glass from broken bottles, metal tomato puree cans, and batteries.

Figure 10: There were 11 beach cleans on the village transect during Phase 184. A total of1,185 pieces of litter were collected (808 burnable, 377 non-burnable). The 9 beach cleans onthe control transect had a total of 565 pieces of litter collected (502 burnable, 63 non-burnable).Overall, the village transect had much higher quantities of litter in both categories.

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A total of 65 (35 village, 30 control) beach cleans were conducted between Phases 182, 183, and 184.Only two beach cleans were conducted during Phase 181 and will not be included in the results. A totalof 7,290 individual pieces of litter were collected from the upper tree line, sand, and mangrove roots.Throughout all phases, the majority of litter collected on the village transect was highest in the mangroveroots with 2,674 pieces being collected in comparison to the 675 pieces collected on the control transect.Both transects were similar in overall litter collection in the sand and upper shoreline areas. On thevillage transect, 1,567 pieces of litter were collected in the sand/middle and 1,330 pieces on the controltransect (figure 11). More litter was collected on the control transect (550 pieces) in the upper transectthan the village transect (494 pieces). The most common “burnables” collected on each side were hardplastics, soft plastics, plastic bags, plastic bottles, and food wrappers. Most of the “non-burnables”collected were metal food cans, pieces of glass, and batteries.

Figure 11: There were 65 beach cleans throughout Phases 182, 183, and 184. A total of 7,290pieces of litter were collected in the mangrove roots, sand/middle, and upper shorelines of thevillage and control transects. The highest amount of litter was collected in the mangrove roots ofthe village transect (2,674 pieces). The sand/middle and upper shorelines were similar betweenthe village and control transects.

3.2.4 Discussion

Plastic items, including bags and bottles, were the most common type of litter found along the beach,which is consistent with previous published works (Santos, Friedrich, and Sul 2008). This study foundthat plastic accounted for 76% of the sample debris. As part of the village transect is directly in frontof Ambalahonko, it can explain why there is such a higher percentage of debris found compared to thecontrol transect. There are several reasons that can lead to the large quantities of litter found on thebeach. First, the lack of litter collection and processing facilities near Ambalahonko give locals almostno other alternative to dispose of their waste and there is no alternative for the use of single use plasticslocally available. There is also a lack of education about the impacts of anthropogenic litter on beachesand in the oceans. The interest shown by local children to help with Frontier beach cleans highlightsan opportunity to engage further with the community on environmental awareness and conservationactivities. In the future, it would be beneficial to involve the community more by having large beachcleans where locals can join Frontier regularly. We will also begin to educate them more with thecommunity project on the effects of plastics and other pollution in the ocean in the hope that it willencourage them to dispose of waste properly.

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3.3 Hawksbill Turtle Survey

3.3.1 Introduction

Five of the world’s seven species of sea turtles are found in the Indian Ocean waters surrounding Mada-gascar. In the coastal waters of the Nosy Be area, a prominent species is the hawksbill sea turtle,Eretmochelys imbricata (Hays et al. 2010). Hawksbills are closely associated with, one of the most en-dangered of all marine ecosystem types, coral reefs (Meylan and Donnelly 1999). The Indian Ocean hashistorically been an extremely important area for the hawksbill turtle which once hosted large popula-tions of hawksbills that likely included tens of thousands of females nesting annually (Humphrey andSalm 1996; Hayes et al. 2010).For the last few decades, the population of hawksbill turtles has drastically declined throughout theIndian Ocean due to human activities (Shanker et al. 2004) and in 1996 their status was changed tocritically endangered (IUCN 2018). In the last century, the hawksbill turtle population size has sufferedan over 80% reduction. Of all the species of marine turtles, the hawksbill has endured the longest andmost sustained history of exploitation (Meylan and Donnelly 1999). Fisheries by-catch and coastal de-velopment are often ranked as the top hazards to sea turtle species. Nest predation and direct take followas the second and third greatest threats, respectively (Donlan et al. 2010). However, a more recent andworldwide threat to sea turtle populations is that of climate change and global temperature increase.Phenotypic sex in sea turtles is determined by nest incubation temperatures, with warmer temperaturesproducing females and cooler temperatures producing males (Kamel and Mrosovsky 2006). Therefore,global warming poses serious threats to species that exhibit temperature dependent sex determination(TSD), such as marine turtles (Marcovaldi et al. 2014). As sex determination and hatching success aredependent on nest temperature, nest sex ratios may be skewed towards a predominantly female output,and eggs may be consistently exposed to temperatures that exceed thermal mortality thresholds (Fuenteset al. 2009). Highly skewed female biased hatchling sex ratios in sea turtle populations could have seriousrepercussions for the long-term survival of these species (Kamel and Mrosovsky 2006).With hawksbill sea turtles listed as ‘critically endangered’ and the current threat of both climate andanthropogenic factors, it is imperative that management and monitoring of sea turtle populations in thecoastal waters of Madagascar is of high concern. This study therefore aims to conduct surveys aroundthe Nosy Vorona Passage by monitoring and recording individual sightings looking at sex, behaviour andvisual health of each individual. Knowledge of the primary sex ratio of populations with TSD is keyfor providing a baseline to inform management strategies and to accurately predict how future climatechanges may affect turtle populations (Marcovaldi et al. 2014). Frontier is hopeful that if reliable resultsare achieved in the future, that we will be able to work with other conservation organizations, localvillages and local governments.

3.3.2 Methodology

Snorkel surveys were conducted at Home Reef, Nosy Vorona, and Three Brothers and last approxi-mately 45 minutes using active search methods with a minimum of two snorkelers per team. Sites weredetermined in coordination with the BSP reef surveys (Markham and Brown 2007). Once the reef wasspotted, the snorkelers would proceed to swim in the area of the reef for 45 minutes. One surveyorcollected data via a dive slate while the other took photographs using a variety of underwater actioncameras, preferably GoPro. Before their first survey, volunteers would be briefed on each category of thedive slate. Dive slates have categories for species, sex, size, behavior, features, interaction with snorkel-ers, number of vessels, and vessel distance. Behaviors included swimming, resting and eating. Size oftheir carapace was estimated in categories beginning with less than 60cm and ending with greater than100cm. Categories in between those size ranges were grouped in intervals of 10cm (61-70, 71-80, 81-90,91-100). A neutral interaction was if the turtle continued with what it was doing, a negative interactionis if the turtle swam away, and a positive interaction was if the turtle swims towards a snorkeler. Somefeatures include barnacles, lumps on the head or flippers, and damaged carapace. Photos of the turtleswere taken on each side of the face, as those are their identifiable features, similar to a human fingerprint.The photos were sorted by date and site to late be used on the I3S Pattern Program, this enabled theindividual identification of turtle using facial profile photographs (Reisser et al. 2008). This method is anon-invasive technique to identify individual and create a catalog of population dynamics in the area.

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3.3.3 Results

There were a total of 30 turtle surveys over three phases this year (none were conducted during phase181). There were more surveys overall at Home Reef (17) than at Vorona (7) and Three Brothers (6).This is due to Home Reef being more accessible as it is just a short swim from camp while the other sitesrequire about a 15-minute boat ride. At Vorona and Three Brothers, if there are not enough surveyorsto have a reef monitoring team and a turtle survey team then no turtle surveys will be conducted forthat day. The amount of surveys at each site is highly variable upon the number of volunteers.

There were a total of 27 hawksbill turtle sightings with no sightings occurring on 10 of the surveys.Overall there were 22 females and only five males (figure 12). No males were spotted at either Voronaor Three Brothers. There were a total of six surveys at Three Brothers and there were eight femalesspotted. Four were in the range of 51-60cm, two at 61-70cm, and two at 71-80cm. They were all notedto be either swimming or feeding with interactions with snorkelers being neutral or negative except one,which was positive. There were three surveys at Vorona in which no turtles were sighted. The fourfemale turtles that were sighted varied in size with one estimated at 51-60cm, two at 61-70cm, and oneat 71-80cm. Again there was only one positive interaction with the remaining being negative. Therewere no sightings on seven surveys at Home Reef. Of the 15 turtles sighted at Home Reef, 10 werefemale and five were male. The majority of females (5) were in the range of 51-60cm while three were61-70cm and two were 71-80cm. Three of the males were in the range 71-80cm and two were 61-70cm.There were no positive interactions with the hawksbill turtles at Home Reef. Three of the males weredocumented to have a negative interaction and two had a neutral interaction with snorkelers. Six ofthe females had a negative interaction and four were neutral. Again, the most common behaviours wereswimming, resting, or feeding. There was one exception that a turtle was being cleaned by a blue streakcleaner wrasse, Labroides dimidiatus. The most common features turtles had in common were barnacleson their carapace.

Figure 12: A total of 30 turtle surveys were conducted at three sites (Home Reef, Vorona, andThree Brothers)throughout phases 182, 183, and 184. Of all the turtle sightings, 22 individualswere female and 5 were male.

3.3.4 Discussion

The hawksbill turtle surveys began in the second phase of this year and although Frontier data isindicating that climate change is affecting the sex ratios of hawksbill turtles in the Nosy Vorona Passage,there still needs to be significant more data to support this theory. However, our initial findings aresupportive of other studies which have displayed sex skews in hawksbill turtles. For example, Marcovaldiet al. 2014, found a strong female bias when studying hawksbill hatchlings in Brazil. However, this studyalso states that there is a lack of data regarding sex ratios in Hawksbill turtles. Therefore, it is of highimportance to continue with this study. Surveys also need to be completed consistently at each site asthey have different ecosystems, which can impact how many turtles visit each site. In the future, it

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may be beneficial to compare turtle data with reef bio-monitoring data. Feeding was one of the mostcommon behaviors of turtles sighted on surveys and comparing the health of the reefs could indicateif the turtle’s diet is influenced by the health of the reefs. There were very few positive interactionsbetween the turtles and the snorkelers, which suggests that there is some human impact in the NosyVorona Passage affecting their behavior. Most of the interactions were negative, which can indicate thatthe turtles view the snorkelers as a threat and swim away. Hayes et al. 2010, found that the presenceof recreational diver’s lead to a reduction in the time turtles spent feeding and breathing. In the earlystages of this study it is currently unclear to what extent the presence of snorkelers has on the behaviorof the hawksbill turtles found at the study sites.While documenting the skew in sex ratios of the hawksbill turtles in the Nosy Vorona Passage is importantfor future turtle conservation, it would also be beneficial to create a catalogue of individuals using theI3S Pattern Program for photo identification. However, this process can be complicated when it comesto training new volunteers, as the turnover is quite high. Photographs have been taken in the past andstaff is currently working on sorting through photos from past phases to begin the catalogue to hopefullybe used in the future. While over the past few months, the majority of hawksbill turtles spotted havebeen female, which supports climate change skewing ratios to be more female dominant, it is still tooearly in the research to make any conclusions about turtle populations in the Nosy Vorona Passage.

3.4 Proposed Research Plan for Phase 191

• Continue long-term biomonitoring of the coral reefs in the area (fish, invertebrate, nudibranch, andbenthic).

• Benthic protocol will be adapted to record in more detail the composition of the reef, to depict thereef more accurately.

• Continue beach cleans on each side of camp and extend to village of Antafondro. Also begineducating the village about marine pollution and involve them more with beach cleans.

• Turtle surveys will continue and begin creating a catalogue of individuals using photo ID.

• Begin assessing mangrove species coverage and crab species that inhabit mangrove areas.

• Mangrove health survey will be added to the beach conservation project. This will monitor abun-dance, health and growth rate of the surrounding mangroves.

• Mangrove restoration and transplantation project will be set up to support the mangrove healthsurvey and expand the beach conservation project.

• To greater enhance the learning and development or Research Assistant Divers, debriefs will beconducted after each dive to provide feedback to increase the reliability of the data.

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