An assessment of local fisheries in Diego-Suarez Bay, Madagascar

Frontier Madagascar Environmental Research
REPORT 22
An assessment of local fisheries in
Diego-Suarez Bay, Madagascar
2009

Frontier Madagascar Environmental Research
Report 22
An assessment of local fisheries in
Diego-Suarez Bay, Madagascar
Narozanski, A. J., Steer, M. D. and Fanning E. (eds.)
ANGAP
Conservation International
Diego Suarez
2009
Society for
Environmental
Exploration
UK

Suggested Technical Paper citation:
Frontier Madagascar (2009) An assessment of local fisheries in Diego-Suarez Bay,
Madagascar. Narozanski, A. J., Steer, M. D. and Fanning E. (eds.) Frontier Madagascar
Environmental Research Report 22. Society for Environmental Exploration, UK; ANGAP;
Conservation International.
The Frontier -Madagascar Environmental Research Report Series is published by:
The Society for Environmental Exploration
50-52 Rivington Street,
London, EC2A 3QP
United Kingdom
Tel: +44 (0)20 7613 3061
Fax: +44 (0)20 7613 2992
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Web Page: www.frontier.ac.uk
ISSN 1479-120X (Print)
ISSN 1748-3719 (Online)
ISSN 1748-5126 (CD-ROM)
© Frontier-Madagascar 2009
iii

The National Association for the Management of Protected Areas in Madagascar (ANGAP)
ANGAP (or The Madagascar National Parks Association) is a private association, established in
1990 to manage Madagascar's network of protected areas. ANGAP promotes and manages nature
conservation alongside responsible sustainable development, therefore ensuring that local
communities benefit directly from conservation.
Conservation International (CI)
CI is a nonprofit organization that seeks to protect Earth’s high-biodiversity wilderness and
hotspots. The group is known for its partnerships with local non-governmental organizations and
indigenous peoples, demonstrating that human societies are able to live harmoniously with
nature. This mission is based around three guiding principles of cutting-edge science,
comprehensive partnerships, and concern for human well-being. Since 1987, CI have conserved
over 143 million terrestrial acres and 80 million acres of marine area.
The Society for Environmental Exploration (SEE)
The Society is a non-profit making company limited by guarantee and was formed in 1989. The
Society’s objectives are to advance field research into environmental issues and implement
practical projects contributing to the conservation of natural resources. Projects organised by The
Society are joint initiatives developed in collaboration with national research agencies in cooperating
countries.
Frontier-Madagascar Marine Research Programme (FM MRP)
The Society for Environmental Exploration (SEE) has been conducting research into
environmental issues since 2000 under the title of Frontier-Madagascar. The Frontier-
Madagascar Marine Research Programme conducts research into biological diversity and
resource utilisation of both marine and coastal environments, in Diego-Suarez Bay, in
collaboration with ANGAP, Conservation International, and IBIS.
For more information:
Frontier -Madagascar
BP41, Antsiranana, 201
MADAGASCAR
Tel/Fax: +261 (0) 20 82
23117
E-mail:
frontier@wanadoo.mg
Society for Environmental
Exploration
50-52 Rivington Street,
London, EC2A 3QP. U.K.
Tel: +44 (0) 20 7613 3061
Fax: +44 (0) 20 7613 2992
E-mail: research@frontier.ac.uk
Internet: www.frontier.ac.uk
iv

ACKNOWLEDGEMENTS
This report is the culmination of the advice, co-operation, hard work and expertise of many people. In
particular acknowledgements are due to the following:
THE NATIONAL ASSOCIATION FOR THE MANAGEMENT OF PROTECTED AREAS IN
MADAGASCAR (ANGAP)
Director of the Nosy Hara park Mr. Jaomanana
CONSERVATION INTERNATIONAL (CI)
Regional Director for Marine Projects : Ms. Monica Tombolahy
SOCIETY FOR ENVIRONMENTAL EXPLORATION (SEE)
Managing Director: Mrs. Eibleis Fanning
Research and Development Manager: Dr. Mark Steer
Research and Development Officers: Ms. Elisabeth Wulffeld
Ms. Olivia Couchman
Mr. Leigh Richardson
Mr. Robert Perryman
FRONTIER-MADAGASCAR
Country Co-ordinator: Ms. Elizabeth Middleton
Assistant Country Coordinator: Ms. Chloe Searl
Principal Investigator: Mr. Andrzej Narozanski
Research Officers: Ms. Alison Evans
Ms. Vivienne Johnson
Assistant Research Officers: Mr. Alex Leman-Lawrie
Mr. Anthony King
Ms. Jennifer Wilmes
Ms. Joanne Eaton
Ms. Josephine Pegg
Ms. Katie Cherry
Mr. Michel Trommelen
Dive Officer: Mr. Daniel Shultz
Research Assistants:
Annelies Vermeulen, Shireen Darabi, Katie Strange, Lucy sanders, Andrew Derrick, Charlotte Vallily,
Max Bodmer, Edward Sockett, Hannah Mold, Paul Codd, William Salter, Nicholas Marsden, Elspeth
Esdon, Nick Riddiford, Sam Davies, Frances Blow, Penny Anderson, Hugo Flaux, Alexander Critchley,
Maia Sterenfeld, Julia Haywood, Miles Ramsden, Bryony Collins, Jennifer Allan, Laura Shearer, Robyn
Smith, Joshua Lee, Anna Chouler, Kate Bonham, Sarah-Jane Trehane, Gareth Wilmot, Benjamin Miles,
Manto Konstanto, Alexander Smith, Joe Tuck, Luke Gordon, Zofia Harries, Fran Billingsley
Also thanks to the people of Antsisikala and Ramena, plus many thanks to the Malagasy interpreters
whose help was invaluable.
v

Table of contents
EXECUTIVE SUMMARY 2
1 INTRODUCTION 3
2 METHODS AND MATERIALS 4
2.1 SURVEY AREA AND STUDY SECTORS 4
2.2 SURVEY METHODS 4
2.2.1 SOCIO-ECONOMIC DATA 5
2.2.2 RESOURCE STATUS 5
2.2.3 VISUAL OBSERVATIONS 5
3 RESULTS 6
3.1 SOCIO-ECONOMIC DATA 6
3.2 RESOURCE STATUS AND VISUAL OBSERVATIONS 10
3.2.1 LINE INTERCEPT TRANSECT (LIT) 10
3.2.2 UNDERWATER VISUAL CENSUS (UVC) 10
3.3 VISUAL OBSERVATIONS 12
3.3.1 FISHING AREAS 12
3.3.2 FISHING METHODS 13
3.3.3 CATCH-PER-UNIT EFFORT 15
3.3.4 DIEGO-SUAREZ FISH MARKET PRICES 15
4 DISCUSSION 16
4.1 SOCIO-ECONOMIC AND VISUAL OBSERVATIONS 16
4.2 RESOURCE STATUS (UVC AND LIT) AND VISUAL OBSERVATIONS 19
4.3 SUMMARY OF POSSIBLE CONSERVATION MANAGEMENT METHODS 20
4.4 SUMMARY OF TOPICS FOR FUTURE STUDY 20
5 CONCLUSION 21
6 REFERENCES 22
APPENDICES 24
1

EXECUTIVE SUMMARY
The artisanal fishery in Diego-Suarez Bay, north Madagascar is an active fishery where fishermen use
multiple methods based on traditional techniques. Prior to this study there has been virtually no
documented assessment of fishing activity within the bay. A total of forty fishermen from two important
fishing villages were interviewed on fishing practices, fishing habits, economic considerations, local
perceptions on fish stocks, temporal changes and environmental awareness. Interview data was
complemented with a direct investigation of reef health with respect to hard coral cover and fish stocks.
The fishery targets multiple families of reef and reef associated fish as well as invertebrates. Carangidae,
Lutjanidae and Mullidae were the most common fish families targeted, using five principal fishing
techniques; hook and line, gill nets, seine nets, spear guns and traps. There was a significant difference in
the catch sizes and the types of fishing gear used between the two villages surveyed. Catch size and fish
abundance was reported by the fishermen to have decreased in recent years. Fishermen opinions ranged
on the cause of this decrease, with no universal outstanding answer given. The most likely explanation
lies in increased pressure on marine resources caused by the current steady rise in the local population and
increasing tourism. Although the fishery is not currently in a bad state, productivity and sustainability
could be improved through education of locals and simple management strategies. The bay offers a good
opportunity for proactive conservation programmes to be implemented before large scale problems start
to become manifest.
2

1 Introduction
Since ancient times, fish have constituted a major source of food for humans and fishing has provided
employment and economic benefits to those engaged in this activity. The wealth of marine resources was
once assumed to be an unlimited gift of nature. However through increased knowledge and the dynamic
development of fisheries science post Second World War, this myth has faded in face of the realisation
that aquatic resources, although renewable, are not infinite and need appropriate management
(Keenleyside, 1997; Pauly, 2008).
Fishing is widely recognised as having a major influence on marine ecosystems throughout the world.
Industrial fishing has been well documented to cause serious habitat degradation through benthic
dredging and trawling (Watling & Norse, 1998) and over-exploitation of species (Myers et al., 1997).
Artisanal fisheries, by comparison, operate on a smaller scale and tend to be associated with relatively
low environmental impacts (Hawkins & Roberts, 2004; Dalzell, 1998). These fisheries are near-shore and
exploited by small-scale fishers using labour intensive methods with little or no modern technology.
Typically the people carrying out these activities are part-time, subsistence fishers who use a multiple of
fishing techniques to target multiple species. In the Pacific, artisanal fisheries have been documented to
have had no significant impact on the state of coral reef ecosystems despite constant use over the last
thousand years (Dalzell, 1998). However, this finding is contradicted by numerous other studies
highlighting the negative impacts artisanal fisheries can have on reef systems and fish biomass (e.g.
Adam et al., 1997; Colbentz, 1997). Despite their perceived impacts, artisanal fisheries are especially
important in developing countries, throughout the tropics in particular. An estimated annual yield of six
million tonnes per year is harvested from tropical coral reefs (Munro, 1996), indicating their importance
for local peoples.
Few methodological modifications have been implemented in the world’s artisanal fisheries over the last
few centuries; the introduction of motorised boats and modern materials (such as nylon filament lines and
artificial bait) being the main changes (Hawkins & Roberts, 2004). What has changed, however, is the
increase in the number of people being supported by these fisheries. The number of artisanal fisheries in
developing countries has increased significantly in recent years, driven by increasing coastal populations
(FAO 2000). Documented impacts include the reduction in life expectancies of certain specie s (Munro,
1983), elimination of species from reef areas (Wells, 1997), long-term reef degradation (Ginsburg et al.,
1994) and the mass depletion in targeted genera (Koslow et al., 1994). Typical of many subsistence and
traditional forms of renewable resource use, over-exploitation can result in irreversible economic, social
and cultural harm to the very people causing the damage (Tundi, 2000).
Diego-Suarez Bay, situated in the far north of Madagascar, has a thriving fishing industry about which
little is known. The bay has numerous sub-bays, which present a range of tropical habitats (coral reef, sea
grass and mangrove). These habitats are an important resource and support neighbouring villages with
reef fisheries. Artisanal fishing methods using traditional techniques with modern material are used daily
throughout the bay. Due to a variety of terrestrial and anthropogenic influences the bay exhibits a wide
range in the quality of its reefs, in terms of coral cover, fish diversity and fish biomass.
This report assesses the state of the fishery, through describing the methods and materials used by the
fishermen, gaining local opinion, identifying environmental impacts, and assessing catch data. We
recommend that proactive conservation programmes should be implemented to ensure the sustainability
of the local fisheries.
3

2 Methods and Materials
2.1 Survey area and study sectors
The study took place from July 2005 to December 2008 around Diego-Suarez Bay, Northern Madagascar.
Diego-Suarez Bay is a shallow tropical bay (mean depth 30m), open to the Indian Ocean in the east. The
interior of the bay is characterised by numerous small islands or Nosy(s) as they are known in Malagasy,
and a coastline lined with many, almost continuous, shallow fringing reefs. The bay has been divided into
study sectors and islands to enable long-term monitoring by SEE Frontier Madagascar (figure 1). Each
sector/island has been further divided into study sites (ranging from 2-26 sites per sector/island) with each
site being a maximum of 300m apart from each other. Ramena is a small fishing village west of the
mouth of the bay (figure 1), which is popular with tourists. Fishing is the main activity for locals in this
village, with some fishermen catering for tourist excursions as well. Antsisikala in the north of the bay
(figure 1) is a small village with approximately 50 houses. They generate the majority of their income
through zebu farming, while fishing is principally for subsistence and small-scale trading.
Figure 1. Map of Diego-Suarez Bay, displaying 11 designated study sectors and islands
2.2 Survey Methods
To fulfil the objectives of the study, four survey methods were used:
• Questionnaires to gain information on the current status of the fishery and fishermen’s opinions.
• Line Intercept Transect (LIT) to determine the percentage of hard coral cover at each study site
(part of a SEE Frontier long-term monitoring project).
• Underwater Visual Census (UVC) to calculate the biomass of fish at each site (part of a SEE
Frontier long-term monitoring project).
• Visual observations of artisanal fishing effort, techniques used and species targeted.
4

2.2.1 Socio-economic data
A total of 21 fishermen were interviewed from the village Antsisikala (figure 1) on two separate
occasions in November 2006 and then in August 2008 and nineteen fishermen were interviewed in
Ramena (figure 1) in December 2006. The questionnaires consisted of 25 questions (Appendix 8.1) and
each interview was conducted using a Malagasy interpreter lasting approximately 40 minutes. Questions
centred on fishing practices, fishing habits, economic considerations, local perceptions on fish stocks,
temporal changes and environmental awareness. The estimated catch per unit effort (CPUE) value was
calculated in (kg per man/h) using information on catch weight and time-spent fishing for each type of
equipment.
2.2.2 Resource status
The Line Intercept Transect (LIT) method was used to calculate percentage cover of hard coral genera at
a given survey site. The length of each benthic substratum, found directly underneath a 20m transect line
was recorded (in cms). If the substrate was hard coral, it was recorded to genus level. Data collected using
the LIT method was collected between July 2005 and September 2008. Spearman’s rank correlations
were calculated to determine relationships between fishing activity and fish biomass, fish diversity and
hard coral cover.
To assess fish species diversity and biomass at a given survey site the Underwater Visual Census (UVC)
technique was used. The size and frequency of fish encountered within an area 2.5 m on either side and 5
m above a 20m transect was recorded. The size of any fish entering this space was estimated to the
nearest 5cm and recorded on a specially designed slate. Species recorded were in the families: Lethrinidae
(emperors), Lutjanidae (snappers), Labridae (wrasse), Serranidae (groupers), Mullidae (goatfish),
Siganidae (rabbitfish), Haemulidae (sweetlips), Balistidae (triggerfish, Acanthuridae (surgeonfish),
Carangidae (jacks and trevallies), Dasyatidae (stingrays), Holocentridae (squirrelfish and soliderfish),
Apogonidae (cardinalfish), Caesionidae (fusiliers), Nemipteridae (monocle breams and spine cheeks),
Chaetodontidae (butterflyfish), Pomacanthidae (angelfish), Pomacentridae (damselfish), Scaridae
(parrotfish), Scrombridae, (mackerel) Lethrinidae (emperors) and Sphyraenidae (barracuda). Data
collected using the UVC method is available between July 2005 and December 2008 for all sectors and
islands.
The number of LIT and UVC surveys carried out during this time in each sector or island is as follows;
Nosy Fano=29, Nosy Koba=34, Ramena=8, Nosy Langoro=12, Nosy Loapasana=14, Nosy Volana=5,
Sector 0=63, Sector 1=46, Sector 2=74, Sector 3=67, Sector 4=71, Sector 5=68, Sector 6=22, Sector
7=14, Sector 8=19, Sector 9=2, Sector 10=4, Sector 11=9 (a total of 561). During January to December
2008 the following number of surveys were carried out; Nosy Fano =12, Nosy Koba=22, Nosy
Langoro=6, Sector 0=21, Sector 1=15, Sector 2=32, Sector 3=33, Sector 4=21, Sector 5=12 (a total of
175). See Frontier-Madagascar (2003) for more details on the LIT and UVC methods.
2.2.3 Visual Observations
During UVC and LIT surveys, systematic observations were made concerning levels of coral damage
caused by fishing activity, fish species caught in nets or on lines by fishermen, types of gear used and
materials, number of fishers involved in fishing activities, plus any additional relevant information
observed during fishing activity. The presence and number of fishing boats was also noted at each site
before and after the UVC and LIT surveys were performed. Data was collected between July 2005 and
December 2008 for all sectors and islands. An estimated CPUE value was calculated in (kg per man/h) on
observations made during fishing activity. Using mean weight of catch, gear used and time spent fishing
per day, where available from the questionnaires or observed during fishing activity, an estimated CPUE
value has been calculated.
5

3 Results
3.1 Socio-economic data
Percentage of fishermen
50
45
40
35
30
25
20
15
10
5
0
fishing subsistence transport moral
obligation
Primary interest in the bay
Figure 2. Main interest of fishermen in Diego-Suarez Bay (n=27)
Number of fishermen
16
14
12
10
8
6
4
2
0
Carangidae (Jacks)
Lutjanidae
Mullidae
Scaridae
Siganidae
Lethrinidae
Serranidae
Acanthuridae
Labridae
Haemulidae
Carangidae (Trevallies)
aesthetics
aethestic religious conservation tourism
Caesionidae
Pomacanthidae
Carcharhinidae
Fish / invertebrate families
Octopodidae
Scrombridae (Mackerel)
Scrombridae (Tuna)
Holothuria spp.
Figure 3. Principal fish/invertebrate families targeted by fishermen in Diego-Suarez Bay (n=21). Carangidae
and Scrombridae have been subdivided to differentiate between the two main genre targeted within those
families
Fishing, subsistence and transport are the three principal interests in Diego-Suarez Bay according to
fishermen interviewed (figure 2). Conservation of the bay and its resources was considered to be the main
Balistidae
Dasyatidae
Sphyraenidae
6

interest in the bay by three fishermen (9%). Moral obligation, aesthetic value, religious value and tourism
were not considered to be important by any of the fisherman.
Targeting multiple families was common among fishermen with 80% targeting three or more. Fishing in
Diego-Suarez Bay targets the highest trophic level of coral reef fish, with 57% of the targeted species
being piscivores and macroinvertebrate feeders. Carangidae (Jacks), Lutjanidae and Mullidae were the
most sought after families, followed by Scaridae, Siganidae, Lethrinidae, Serranidae and Acanthuridae
(figure 3).
Percentage of fishermen
100
90
80
70
60
50
40
30
20
10
0
Common
fish
Highest
income
Gear People like
these fish
Reason for targeting fish
Figure 4. Fishermen’s reasons for targeting fish species (n=40)
Percentage of fishermen
100
90
80
70
60
50
40
30
20
10
0
Fishing
net
Seine net Spear gun Hook and
line
Fishing Gear Used
Used to
catching
this
species
Poison Trap
Figure 5. Percentage of fishermen using each type of fishing gear (n= 40)
Fishermen targeted fish principally due the fish being common and widely available. Income and the
availability of gear were less important. Few fishermen targeted fish because they are what people like to
eat. Other reasons included targeting species because they are considered to be large spawners, as well as,
targeting certain species allows others to thrive
The mean number of days spent fishing per week is four, with 33% of fishermen fishing every day during
the week. Monday (16%) and Sunday (11%) were the two most popular individual days to go out fishing,
7
Other

ut the majority of fishermen do not have a specific day, fishing on any day of the week (44%). The
number of hours spent fishing ranged from one to twelve hours per day, with a mean of five hours.
The months around the turn of the year (November, December, January and February) were the most
favourable months in which to fish with December being the most popular (11%).
The most common types of fishing gear used were the fishing net and a hook and line (figure 5). There
was a significant difference in the types of gear used by fishermen in Ramena and those interviewed from
Antsisikala. Chi-square contingency tests using the total frequency counts for each fishermen using each
gear from Ramena or from Antsisikala showed there is an association between gear use and where the
fishermen came from. (χ 2 = 14.97, df = 5, p < 0.010). Seine netting was used by 56% of the fishermen in
Ramena, compared to none of fishermen from Antsisikala. According to 92% of fishermen, fishing
techniques had not changed in the years that they had been fishing.
Percentage of fishermen
100
90
80
70
60
50
40
30
20
10
0
yes when fish
too small
yes when fish
is non-target
yes when its
not a valuable
species
not good to
eat
Reason for throwing fish back
Figure 6. Reason for throwing fish back (n=36)
do not throw
anything back
Seventy-two percent of the fishermen would throw fish back while 28% would not. Of the 72% that said
yes, 67% of fishermen throw fish back if they are too small, 31% if they are non-target species, 14% if
they not valuable and 0% throw fish back if they are not good to eat.
The majority of fishermen reported a mean daily catch weight between 1-25kg (77%). Within this size
class the weights varied from 2kg to 25kg. Weight classes 25-49kg and 50-75kg had a lower frequency
(both 10%). However, there was a significantly higher frequency of catches from the weight classes 25-
49kg and 50-75kg by fishermen from Ramena, than from Antsisikala (χ 2 = 8.53, df = 3, p < 0.036).
8

10%
10% 3%
77%
1-24kg
25-49kg
50-75kg
> 75 kg
Figure 7. Percentage of fishermen reporting daily catch weight in four size classes (n=40)
Selling of a catch depended mainly on the size of the catch according to 41% of the fishermen
interviewed, 22% said they would sell it every 2 to 3 days. Only 9% of fishermen chose not to sell their
catch at all, fishing only for subsistence. The city of Diego-Suarez was the most popular place to sell fish
(54% of fishermen) and Antsisikala the second (31%).
Table 1. Fishermen’s opinion of the state of fish resources in Diego-Suarez Bay (n=40)
Fish Resources Decreased (%) No change (%) Increased (%) Don't know (%)
Catch size 58 38 3 3
Abundance 83 13 3 3
Average size 40 55 3 3
Table 2. Fishermen’s opinion of the reason for change in fish resources in Diego-Suarez Bay (n=39)
Reason for change % fishermen
More fisherman 13
Effects of climate change 10
Seasonal 8
Bigger octopus moving to deeper sea 8
Use of Seine nets by fishermen in Ramena 5
Overfishing 5
Coral damage through spear fishing techniques 3
Less rain has led to more fishing instead of farming 3
Other 5
I don't know 10
The majority of fishermen have perceived a recent decline in both catch size and abundance, whilst the
average size of fish caught was reported to have stayed the same. Very few fishermen perceived that there
had been any increase in catch size, abundance or average size (table 1). There was no common answer to
why fish catch had changed. Answers were split among the nine main categories (table 2). The highest
response given was an increase in fishermen causing the decline, followed by the effects of climate
change. A number of fishermen explained climate change having caused the seasons to become more
unreliable and difficult to predict. Ten percent could give no reason for why there has been a change.
9

Table 3. Fishermen’s opinion on resource use in Diego-Suarez Bay (n=40)
Question
Fishing should be restricted to specific areas 22 28 11 39 0
Use fishing nets with > 4 cm mesh 33 44 17 6 0
Communities should work together on resource use 39 39 11 11 0
Deforestation in coastal areas should be stopped 50 39 0 6 6
Only catch large fish 50 44 6 0 0
Do nothing specific, there is enough fish 0 56 6 33 6
Fish on certain days 22 61 6 6 6
A fisherman should decide himself how much fish he catches 22 56 11 11 0
Pray or ask ancestors for more fish 11 44 28 17 0
The government in Diego should control fish catch size 6 33 33 17 11
Eat less fish 33 17 33 6 11
Only catch certain fish species 17 39 28 17 0
Village chief should control the size of fish catches 28 56 11 0 6
Get more tourists to the bay as an alternative source of income 39 44 6 11 0
In response to whether fishing has an impact on the environment 78% of fishermen said it did have an
impact and 28% said it had no impact. The majority of fishermen stated that there were fadys associated
with fishing in Diego-Suarez Bay (71%).
Responses to questions on how best to ensure the availability of marine resources for future generations
varied with no outstanding universal answer for each question (table 3). The majority of people strongly
agreed that deforestation in coastal areas should be stopped and only large fish should be caught. The
greater part of fishermen agreed that: fishing nets with > 4 cm mesh should be used; nothing specific
should be done as there is enough fish; only go out fishing on certain days; a fisherman should decide
himself how much fish he catches; pray or ask ancestors for more fish; only certain fish species should be
caught; the village chief should control the size of fish catches, communities should work together on
resource use and more tourists should be taken to the bay as an alternative source of income. Most
disagreed that fishing should be restricted to specific areas. There was a split majority opinion on two
questions: 1. The government in Diego should control fish catch size (33% agree and neutral) and 2. Eat
less fish (33% strongly agree and neutral), eating more zebu (a species of domestic tropical cattle) was
mentioned by some fishermen as an alternative.
3.2 Resource Status and visual observations
3.2.1 Line Intercept Transect (LIT)
The relationship between mean hard coral cover and number of fishing vessels at each sector (figure 8)
was tested using Spearman’s rank correlation coefficient. There was no association between hard coral
cover and number of fishing vessels (rs = 0.414, n=17, p > 0.05).
3.2.2 Underwater Visual Census (UVC)
Spearman’s rank correlation coefficient was also used to test if there was an association between mean
fish biomass vs. number of fishing vessels, mean fish species richness vs. number of fishing vessels and
mean number of fish counted vs. number of fishing vessels (fish biomass, mean fish species richness and
mean number of fish counted data only available from January 2008 to December 2008 for sectors 0-5,
Nosy Fano, Nosy Koba and Nosy Langoro). There was an association between mean fish biomass vs.
number of fishing vessels (rs = 0.708, n = 9, p < 0.05) (figure 9). However no association was found for
the other two tests (fish species richness vs. number of fishing vessels, rs = 0.225, n = 9, p > 0.05; mean
number of fish counted vs. number of fishing vessels rs = 0.225, n = 9, p > 0.05).
Strongly
agree
Agree
Neutral
Disagree
Strongly
disagree
10

Mean % hard coral cover
30
25
20
15
10
5
0
0 10 20 30 40
Number of vessels recorded
Figure 8. Relationship between mean hard coral cover and number of fishing vessels recorded in sectors 0-11,
Nosy Fano, Nosy Koba, Ramena, Nosy Langoro, Nosy Loapasana) from July 2005 to December 2008
Mean fish biomass (g/100m)
7000
6000
5000
4000
3000
2000
1000
0
0 10 20 30 40
Number of vessels recorded
Figure 9. Relationship between mean fish biomass (from January 2008 to December 2008) and number of
vessels recorded at sectors 0-5, Nosy Fano, Nosy Koba, Nosy Langoro (July 2005 to December 2008). Dark
line indicates linear trendline
11

Mean number of fish
14
12
10
8
6
4
2
0
0-5
6-10
11-15
16-20
21-25
26-30
31-35
Size class (cm)
Figure 10. Mean number of all fish (families and sectors combined) recorded during a single UVC survey,
found in each size class (data from July 2005 to December 2008)
Fish of small size were relatively commonly recorded during UVC surveys. The frequency of individuals
in each size class decreases rapidly. The larger species (>20cm) that are more likely to be targeted by
fishermen were found at low frequencies (figure 10).
3.3 Visual Observations
3.3.1 Fishing areas
The number of fishing vessels recorded at each survey site in each sector of the bay before and after the
UVC and LIT surveys were used to identify popular fishing sites (figure 11). Sectors 0, 4, 5 and Ramena
had the largest number of fishing vessels present.
36-40
41-45
46-50
51+
12

Figure 11. Map of Diego-Suarez Bay, light grey shaded areas indicate popular fishing sites. Dark grey area
represents the urban conurbations of Diego Suarez
3.3.2 Fishing methods
Ramena
Larger scale fishing and more labour intensive methods were observed in this area of the bay.
Beach seine nets are commonly used. They are made up of a single-panel surround net consisting of a bag
in the middle to hold the catch, a shoulder section at each side and a wing section at each end. The top of
the net has a floated headline made of plastic buoys, polystyrene floats and plastic bottles and the bottom
is attached to a lightly weighted sole rope. Each wing end is connected to a hauling rope. The lengths of
the nets are approximately 200m. The mesh size varies from 1-3cm as the net is made up of many pieces
of different nets. Towards the back of the net and at the cod end the nets are made up of a net with a mesh
size as small as 1cm.
The nets are cast parallel to the shore using boats, approximately 100m from the beach. The number of
fishermen on the boat laying out the net, ranges from 6-10. The hauling ropes are brought ashore and the
nets are pulled into shore. Three to four men with snorkelling equipment are placed in the water around
the net, aggressively hitting the surface of the water to herd the fish into the net. This process lasts up to
an hour with as many as 18 people observed assisting. Once the catch is pulled in, it is dumped on to the
sand and then sorted into species and placed into plastic baskets and washed. The species caught were
identified as sprat (Spratelloides delicatulus), great barracuda (Sphyraena barracuda), sardines (species
unknown), sky emperor (Lethrinus mahsena), blackspot emperor (Letrhrinus harak), dusky rabbitfish
(Siganus fuscescens), half beaks (Hemiramphus far), cornetfish (Fistularia commersonii), white-spotted
puffer (Arothron hispidus), longhorn cowfish (Lactoria cornuta ), three-ribbon wrasse (Stethojulis
strigiventer).
No fish exceeding 30cm were caught in the net, but fish as small as 3cm were observed. Fish of all sizes
were kept and placed in the baskets. Some of the fish 3-5cm in length were left on the beach and not
collected. The fish discarded were the puffers, cowfish, cornetfish, and three ribbon wrasse as they were
13

either poisonous to eat (in the case of the puffer and cowfish) or had very little flesh (in the case of cornet
and three ribbon wrasse). Striped catfish (Plotosus lineatus) that were caught were placed in a hole in the
sand and covered over. This was to prevent any accidental injury caused by touching the venomous
pectoral and dorsal spines
It is worth noting that 23 great barracudas were caught in one of the catches ranging from 15 cm to 30 cm
in fork length. In another of the catches approximately 50 kilos of sardines were observed. The nets were
found to be cast at a frequency of 2 per kilometre. All fishing effort was conducted during daylight hours.
Fishing traps were seen stacked on the beach, however no observations of the fishermen deploying them
were made. Opportunistic fishing with a spear gun was also observed being carried out by the guides
during tourist boat excursions in the bay. Seine netting was observed to the principal method of fishing in
this area.
Outside of Ramena (Including Antsisikala and all other areas surveyed)
The methods used in these areas of the bay are as follows:
Method 1
Single person wooden pirogue approximately 2-2.5m in length.
Powered by a small sail, made from a rice sack and/or a wooden oar.
Small heavy objects such as rocks or scrap metal are used as anchors.
Fishing is done over a reef or on the reef edge.
Baited fishing hooks on a nylon fishing line ranging from 0.5-2mm in diameter are used.
The lines are cast over the side of the boat and are pulled up and down in small movements to attract
fish.
Any fish caught is pulled in by hand, no reel or rod is used.
Fish are placed in a plastic cool box to keep them fresh.
Method 2
Two person pirogue approximately 3-4m in length.
Powered by a small sail made from a rice sack and/or a wooden oar and/or 5HP outboard.
Line fishing as previously described is used, with both fishermen using a line.
Fishermen also used set nylon gill nets with a mesh size of 3-4cm. Nets ranged in length from 15-25m.
The top of the net had a floated headline. These are placed both parallel and perpendicular to the reef
if there is a reef crest. If the reef is gently sloping then the nets were placed above the seabed, again
parallel or perpendicular to the shoreline.
Nets are also placed over seagrass beds.
The nets are left in situ for up to 10 hours and then hauled in.
Again the catch is placed in plastic cool boxes.
The nets tended to be cast out during the late afternoon during daylight hours and were then retrieved
in the morning of the following day before sunrise.
Method 3
Large wooden boats approximately 6m in length powered by outboard engines ranging in horsepower
between 5 and 25 are used in combination with a large sail made from thick cotton. The number of
fishermen aboard a vessel of this size ranges from 2-6 people. Fishing methods observed were both
line fishing and gill net fishing. Three further methods were witnessed, 1) trolling using a thick nylon
fishing line approximately 3mm in diameter with a florescent lour, in the shape of a fish or squid with
a three pronged hook approximately three centimetres in length. The line is cast behind the moving
boat while the boat is either power by an engine or wind; 2) duck diving using snorkelling equipment
to collect edible sea cucumbers and 3) spear gun fishing.
Fishermen using all of the above methods had easy access to the shore, as all the reefs are coastal fringing
reefs or island fringing reefs. This allows them to be able to fish and then camp close to their fishing
ground, reducing their time at sea travelling and increasing their time fishing.
14

The following families were observed in the catches of fishermen’s outside Ramena. Reef species
identified: Lutjanidae (snappers), Haemulidae (sweeetlips), Serranidae (groupers), Scaridae (parrotfish),
Nemipteridae (breams and spinecheeks), Lethrinidae (emperors) and Siganidae (rabbitfish),
Pomacentridae (damselfish); reef associated: jacks and trevallies (Carangidae), sharks (Sphyrinidae) and
barred Spanish mackerel (Scomberomorus commerson).
Referring back to the questionnaire data from Antsisikala and the visual observations made at Antsisikala
and in the other areas of the bay (except Ramena), fishing activity in Antsisikala is likely to be
representative of many of the local villages, while Ramena is more atypical.
3.3.3 Catch-per-unit effort
Due to no specific landing sites or times it makes assessing catches difficult. The CPUE ranged from 0.3
– 0.7 kg person -1 hr -1 for traps, 0.3 – 7.5 kg person -1 hr -1 for hook and line and 1.6 - 3.1 kg person -1 hr -1 for
seine nets.
3.3.4 Diego-Suarez fish market prices
The current price per fish or seafood item is detailed in table 4. Shark, jacks and trevallies were the most
expensive fish to buy. Sea cucumbers are not considered a delicacy in Diego-Suarez and are therefore
exported.
Table 4. Prices of fish/invertebrates from Diego-Suarez market (2008). £1=2800 Ariary (Dec 2008)
Price (Ariary)
Fish / Invertebrate (Malagasy / English)
per kg
Batola / Jacks & Trevallies 6000
Akio / Shark 6000
Thon / Tuna 5000
Orita / Octopus 5000
N/A / Barred Spanish mackerel 5000
Henjy / Rabbitfish 4000
Menaeliky / Snapper 4000
Vovoko / Sweetlips 3000
capitaine / Emperor 3000
Mondrazy / Goatfish 3000
Mahaloky / Fusilier 3000
Riadriaka / Surgeonfish 3000
N/A / Sardine 3000
Tabaka / Wrasse 2400
Mokoba / Ray 2200
Angotra / Parrotfish 2000
Alovo / Grouper 1400
Dingadingana / Sea cucumber exported
15

4 Discussion
4.1 Socio-economic and visual observations
Diego-Suarez Bay is an important resource for many villages and local people who rely on it for many
uses. The results from this study show that fishing and subsistence are the two main interests local
fishermen have in the bay (figure 2). Due to the poorly maintained roads, mainly consisting of unpaved
dirt tracks that surround the bay, the water is an important means of transport and provides local villages
with their principal method of travel. This allows villagers and fishermen alike to travel to and from
villages surrounding the bay as well as to the main ports of Diego-Suarez. Interestingly conservation was
mentioned as an interest by a small minority of fishermen, who believe that conserving the bay’s
resources particularly fish is important for future generations. The extent of the environmental awareness
of the fishermen will be discussed later in this section.
The fish or invertebrates targeted by fishermen ranged considerably. Some fishermen targeted only single
families such as snapper or tuna or octopus, however the majority of fishermen chose to target multiple
families (figure 3). This is characteristic of reef fisheries across the world where the assemblages over
reefs contain a variety of families (Choat & Robertson, 2002). The number of edible species found on and
around reefs is high and with such abundant numbers and diversity of edible fish, fishermen concentrate
fishing effort around these areas. The most popular families that are targeted are Carangidae (Jacks),
Lutjanidae and Mullidae. Fishermen in Diego-Suarez target these families mainly due to how common
they are and therefore most likely to catch (figure 4). The income they bring the fishermen is also
important and in the case of jacks they fetch the highest price at the market (table 4). Fishermen also
target certain fish, as they know where the best places are to catch them and what the best methods are to
use. Knowledge passed down from generation to generation helps fishermen to increase their success
rates.
Fishing equipment can determine what species they catch, as different types of gears used can target
different families of fish. Hook and line method will target mainly resident families such as Haemulidae
and Serranidae, where as gill nets target transitory or schooling families such as Siganidae, Carangidae
and Lethrinidae. Seine nets are largely unselective in what families they target, catching what ever is in
the way. Spear guns in contrast are highly selective as they are used to catch whatever the fisherman
wants. The majority of the equipment used are hook and line and gill nets, of which both were used by
70% of the fishermen interviewed (figure 5). Fishermen from Antsisikala primarily used these methods.
The catch-per-unit effort for hook and line ranged from 0.3 – 7.5 kg person -1 hr -1 . The maximum value
was given by fishermen targeting tuna who could catch one or two large fish in a day using a hook and
line. The type of fishing observed by fishermen using these methods was small-scale fishing typical of
reef fisheries. Enough fish would be caught to provide for a family or village, with any excess being sold.
Calculating the total catch from the bay and comparing it to the estimated productivity is needed to give a
more accurate idea of whether the fishery is currently sustainable or not.
Seine nets and traps are used significantly more frequently in Ramena than outside. As Ramena is
primarily a fishing village (although now becoming a popular tourist resort) with a beach extending
approximately 4km in length, using the seine net is a labour intensive yet viable option as the local labour
force is skilled and experienced in using this technique. The high fishing effort involved, in some
instances will provide enough fish for the labourers, plus extra to sell if required. It therefore can be
highly profitable in terms of catch-per-unit effort, with a maximum of 3.1 kg person -1 hr -1 being identified
in this study. Interestingly this was a very community driven practice with people (both male and female)
who were not part of the fishing group helping out if the size of the catch required it. Those who helped
would receive a small bag of fish as a reward for their efforts.
No destructive techniques are used such as poison or blasting fishing. The lack of any destructive
techniques being used in Diego-Suarez Bay indicates that fishermen have a respect for the conservation of
resources and that fish can be exploited generation after general if their habitats are not destroyed. It also
means that the fishermen believe in their own skills and the techniques they use, without having to change
their methods to less skilled and non-specific methods such as poison or dynamite. A view of “if the fish
16

don’t bite today then tomorrow will be better” was commonly mentioned while talking to fishermen.
According to fishermen, techniques have not changed in the time they have been fishing. What has
changed is the gear material. Nylon fishing line and nets are commonly used, as they are lighter, more
durable and less visible to the fish than traditional natural materials. Although the methods have not
changed the fishing methods have become more effective and will catch a greater proportion of the
available fish. Therefore even if fish stocks are declining, catch sizes might stay the same or even
increase. This will only exacerbate the decrease in fish stocks. Unfortunately the other negative aspect of
using modern material is that they persist in the environment if discarded and are a common cause of
ghost fishing (see Matsuoka et al., 2005).
Fishing practices in the bay are impacted by the weather conditions during the year, with more fishing
being conducted during the rainy season (November to March) when sea conditions are calm. During the
windy season many fishermen head to the Mozambique Channel where conditions are more favourable. If
conditions are favourable then fishing will occur each day of the week for the whole week. The time spent
by fishermen out on their boats ranged from 1-12 hours, while the mode was 4 hours, indicating fishing
practices are mostly fisher specific.
The fishery has very little wastage, with fish being thrown back primarily if they are too small, while only
some fishermen will throw them back if they are not the target species or not valuable (figure 6). Most
fishermen will keep whatever they catch regardless of size or type and even if they are not good to eat
(poisonous fish are discarded). Those using beach seine nets were observed sorting the catch on the sand
into fish type and discarding non-edible or poisonous fish. Discarded individuals, most commonly puffer
fish and trunkfish, were left on the sand and not returned to the water. The lack of selectivity of this
method was clearly identified catching a mix of reef, seagrass and reef-associated fish. Although
fishermen stated in their questionnaires that any non-target fish where returned to the water the contrary
was observed in some cases. A lack of knowledge or understanding persists that, although some fish are
not edible , there is still an ecological importance in returning them to water to rejoin the reef ecosystem.
Education through workshops would be an applicable management strategy to inform fishermen that bycatch
be respected and returned to water. One observed catch saw around 50 kilos of sardines landed
amongst other by-catch fish, which was considered to be an excellent catch. If locals were more selective
in when they cast their nets and only targeting large schools of fish such as sardines, then the by-catch of
reef species could be dramatically reduced. Limited environmental education workshops have been
carried out around the bay (Frontier Madagascar 2007), but there is need for a more sustained approach.
Fishermen using single person pirogues tended to be fishing for subsistence rather than commercial
purposes, using the hook and line method or a small net. These two methods as well as traps and spear
guns do not yield an excessive amount of fish, as most fishermen using these techniques had an average
catch weight of 1-24kg. In contrast fishermen from Ramena have heavier catches than those fishermen
from Antsisikala as a result of using seine nets. The catch was divided amongst the fishermen for their
own consumption, with a small proportion being sold to the local restaurants. Catches in general were
sold depending on the size of the catch, although some fishermen chose to sell every few days. If their
catches were large or they catch some large fish then they will sell them at the market or to restaurants in
Diego-Suarez. With an increase in tourism in Ramena, an increasing amount of fish is being caught and
sold on to the local restaurants. This study does not go into any detail on how the growth of tourism in
Ramena is affecting fishing pressure around the bay. This could be a possible line of enquiry for the
future.
There was no universal reason given by the fishermen on why they thought that catch size and abundance
had decreased during their time fishing (table 1). Many answers were given, with more fishermen fishing
than before (the highest response) and the effects of climate change being the most popular (table 2). It is
not clear whether they fully understand how climate change could be the cause, or whether they are just
using it as a scapegoat. Local opinion is that more young men are becoming fishermen as they see this as
a better option than farming. This may explain why there are more fishermen being observed fishing.
Fishermen may also be travelling further in search of new or better fishing grounds and entering areas that
they would not commonly fish in. However, the most likely cause is population increase. The size of fish
has stayed the same according to the majority of people interviewed, however a large number also
17

elieved that the size has decreased over time. The latter view would agree with the general opinion that
catch size and abundance are decreasing. Either answer is acceptable, as there will be some fish caught
before they grow to a large size as a result of increased fishing pressure. There will also be some
individuals that are able to reach their full adult size before being caught. With a 3.2% yearly increase in
the population of Madagascar in general (Billé et al., 2002), plus an increase in visiting tourists as Diego-
Suarez and Ramena become more developed, has caused an increase in fishing pressure. This study
presents no direct evidence of this, however this phenomenon is well documented by fisheries scientists
globally (e.g. Gedamke et al., 2007). Diego-Suarez Bay will be no exception. A rise in fishing pressure
presents a significant management issue, which should be addressed to ensure fish populations are safe
guarded for future generations.
When questioning the opinions of the fishermen on resource use some interesting answers appeared (table
3). No areas should be restricted to fishing, according to the majority. They believe that they have the
right to fish wherever they want. This view shows that fishermen would show resistance to any such
management plan restricting where they could and could not fish, such as implementing no-take zones.
The level of environmental awareness was high for most fishermen, showing considerable future thought
for the resources in Diego-Suarez Bay. Most agreed to using larger nets to prevent catching smaller fish.
This shows an understanding that by not catching smaller fish, more will grow to sexual maturity and
input back into the population. Similarly catching only large fish will guarantee that they will of a large
enough size to have reached sexual maturity and again would have spawned contributing to future stock
(Mangi & Roberts, 2006; Grandcourt et al, 2006). Some fishermen believed targeting species because
they are large spawners, or targeting one or two species only allowing others to thrive, would have a
benefit on fish stocks. This would be correct, however this may have a detrimental effect on the species
being isolated for targeting (Koslow et al., 1994). In reality this would be difficult to implement as a
management strategy due to nature of a reef fishery, where species are often caught that are not directly
targeted.
Local fishermen still believe that praying to or asking ancestors will improve fish stocks. This view is
predominately from the older generations who still believe that it will have an effect. Very high
percentages of fishermen agreed that deforestation should be stopped in coastal areas. This demonstrates
an awareness of the problems caused by deforestation such as surface run-off and its knock-on effect to
nearby coral reef habitats (e.g. reef sedimentation). Agreeing with the problem could therefore signal the
cooperation of villages to stop deforestation from taking place. By agreeing to only go out fishing on
certain days shows that by limiting the number of days this will limit fishing effort, which therefore could
act as a management strategy toward conserving fish. The majority of fishermen showing that they have a
basic understanding of environmental issues is a comforting thought. Future management therefore has
less risk of being dismissed and would have a good chance of succeeding, if the reasons behind the any
management regulations where explained in detail. Whatever happens in the future, communities must
work together on any resource use issues. Other management methods such as getting Diego-Suarez
government or village chief to regulate fishing activity were agreed with by the majority. A majority also
thought that individual fishermen have the right to set their own quotas. This is slightly contradictory. Its
does however suggest that they would welcome some assistance in managing fishing in the bay.
Eating less fish could be a viable option as a management strategy, however caution would have to be
taken when implementing it, in order to provide an alternative source of protein for local people. Zebu
farming could be encouraged as an alternative, although this would have to be managed carefully as to
not damage surrounding areas. Seafood is important to the Malagasy people both nutritionally and
culturally, so any management proposal reducing the consumption of fish may be difficult to implement
in reality. A more feasible solution would be to try to increase the number of fish in the bay rather than
reducing consumption. The introduction of three or four no-take zones within the bay, in areas such as the
eastern part of sector 4, the western part of sector 5, Nosy Koba and Nosy Langoro would help to
facilitate this. The introduction of no-take zones is well known to protect fish stocks and natural habitats,
allowing fish populations to increase in density and abundance (Ashworth & Ormond, 2005; McClanahan
& Mangi, 2000; Roberts et al., 2001). Increasing the number of tourists in the bay was agreed with by
many of the fishermen from Antsisikala who see how people in Ramena benefit from the presence of
tourists. They make money on tourist excursions, as well as selling catches to restaurants and hotels. This
18

would be a viable management option if the excursions were controlled and any environmental impacts
from an increase in tourism were considered and avoided. Further investigation would have to be
conducted to assess whether the current number of tourists visiting Ramena would be enough to support
an increased number of tour guides.
Fishing was considered to have an impact on the environment by the greater part of fishermen
interviewed. Impacts witnessed during LIT and UVC surveys included; discarded nets attached to coral
colonies, particularly branching and foliose species and in some cases covering about 5m of coral,
discarded fishing hook and line, including one incident of ghost fishing and anchor damage to hard and
soft corals. Most of the study sites exhibited some visible impact to fishing. Education through workshops
providing information on how to reduce impacts would be a simple management plan to reduce damage.
Local Malagasy people observe fadys, which are acts of taboo or banned activities due to superstitious
beliefs. Many fishermen consider there to be fadys associated with fishing. There are a number of local
fadys described by the fishermen which would fit in well with management schemes e.g. no fishing at
night, not using lights at night, no banging the water, no fishing on Tuesdays, Thursdays and Sundays,
and not using metal in the water. These local customs could be combined with other management
schemes to provide a management plan that is considered acceptable by all local people.
The questionnaire results provide an interesting insight into the opinions of the fishermen. As with the use
of questionnaires in general in scientific investigations there is always an element of the interviewee
saying things to please the intervie wer. Due to the questionnaires being conducted through an interpreter
it is difficult in this case to determine whether the interviewees were saying this they considered the
interviewers wanted to hear. However each interview was done separately to prevent the interviewee
having their answers being influenced by others. The fishermen interviewed were very welcoming, were
not distrusting of the questionnaire process and thus we feel that the results are unbiased.
4.2 Resource status (UVC and LIT) and visual observations
A number of relationships were tested to determine if there is a pattern in the biological value of sectors
and the presence of fishermen. No association was found between hard coral cover and number of fishing
vessels (figure 8), fish species richness vs. number of fishing vessels and mean number of fish counted vs.
number of fishing vessels. There was however an association between mean fish biomass vs. number of
fishing vessels (figure 9). Fishermen appear not to be visiting areas where there is high coral cover, high
fish species richness and high fish counts for their chosen areas to fish. Fishermen are fishing areas where
they know there to be a large biomass of fish. How they know this is likely to be through knowledge
passed down from generation on where to find the largest resident fish or where to follow seasonal
migrations of reef associated fish. Personal experience and observations over many years of fishing would
also give them the knowledge on where best to fish.
The mean size of fish found in the bay regardless of species shows that there is a distinct lack of fish
larger than 30cm in length (figure 10). Fishing pressure is likely to have caused this, as all of the reefs in
the bay are easily accessible, fringing reefs. Being able to compare fish size with offshore reefs or barrier
reefs (such as in Nosy Be, northwest Madagascar) that are more difficult to access could prove that
fishing pressure is the cause of a reduced numbers of fish >30cm and not any other anthropogenic or
physical factors. The fact that fishermen are able to travel relatively short distances, fish and then camp
on the nearby shore, allows them more time to fish compared to fishing in the open sea and returning to
land each day. It also allows them to move to a different area if they are not having success. This means
areas can be fished by different fishermen several times a day, increasing fishing pressure. The ease of
access of these reefs could be a confounding reason to the high and continuous fishing pressure.
Investigating the differences in size distributions in areas that have no fishing pressure with areas having
varying degrees of fishing pressure to identify if fishing has an impact or not, would be a key line of
enquiry for the future. Taking into account access to a fishing area, reef quality and other environmental
factors such as exposure and levels of sedimentation would help to provide accurate results.
19

Identifying where the main fishing areas and areas of high fish biomass, species diversity, high numbers
of fish counted and coral cover within the bay provide information for possible management schemes, in
terms of implementing no-take zones.
4.3 Summary of possible conservation management methods
Restricting the use of seine nets to reduce coral damage (McClanahan et al., 1996) and regulating mesh
sizes to reduce juvenile mortality and by-catch could help to prevent the effects of overexploitation, by
increasing juvenile survivorship (Lindholm et al., 2001). The introduction of no-take zones in areas like
the eastern part of sector 4, the western part of sector 5, Nosy Koba and Nosy Langoro would encourage
long-term survival of fish stocks. This would in turn help protect the spawning stock of the exploited
populations, which could lead to the build up and replenishment of adjacent fishing grounds (McClanahan
& Mangi, 2000; Roberts et al., 2001). The introduction of no-take zones would have to be clearly
explained with examples given of how successful it can be given to the local fishermen. This is a very
important point, as clear explanation would help to reassure locals who are currently against having area
restricted to fishing.
Workshops with the local villages that use the bay would provide education on a number of important
issues that could improve the marine environment of the bay. Educating local fishermen on reducing
discarded fishing gear could minimise ghost fishing and coral damage. Using divers (e.g. Frontier
volunteers) to survey areas and systematically remove debris (Donohue et al, 2001) would improve the
reefs ecosystems and reduce the likelihood of ghost fishing. Informing fishermen that by-catch be
respected and returned to water would help to reduce the occurrence of unnecessary mortality and prevent
a reduction in species diversity. Providing information on the size or age at sexual maturity would help
fishermen understand the importance of not removing fish from the ecosystem before they have had the
opportunity to spawn. This could in turn allow the introduction of a minimum capture size to guarantee
that fishermen do not remove fish younger than spawning age. See Mangi & Roberts, 2006 for details on
length at sexual maturity for coral reef fish species.
With the increase in the local population of Diego-Suarez and other villages surrounding the bay plus an
increase in tourism, the sustainability of the fishery will need to be controlled and regulated. The
formation of a Diego-Suarez Bay fishery alliance including representatives from key stakeholders such as
fishermen from each village, business / hotel owners, local government officials from Diego-Suarez and
local conservation organisations such as Frontier, could form the basis for a local management strategy.
The formation of such a body would be able to help manage the bays resources, taking into account the
different needs of each key stakeholder, while incorporating local beliefs and fadys into management
plans.
4.4 Summary of topics for future study
Estimate total catch from the bay by assessing daily catch weights and species composition of catches.
Compare this value with an estimate of the fishery’s productivity to give a more accurate idea of
whether the fishery is currently sustainable or not. From this measures can be suggested to improve its
sustainability.
Assess the impacts of seine net fishing, to provide information on whether steps should be taken to
regulate current activities.
Assess how the growth of tourism in Ramena is affecting fishing pressure around the bay.
Investigate how to provide alternative sources of protein to help reduce fishing pressure.
Examine whether the current number of tourists visiting Ramena would be enough to support an
increased number of tour guides as a possible alternative to fishing.
Investigate the differences in fish size distributions between areas of high fishing pressure and areas of
low fishing pressure to identify if fishing has an impact or not. Other factors such as access to fishing
areas, reef quality and other environmental factors such as exposure and levels of sedimentation need
to be considered to correctly identify the cause of the current fish size distribution.
20

5 Conclusion
Prior to this research very little was known or documented about the fishery in Diego-Suarez Bay. This
study has been able to assess how fishing in the bay is carried out and what potential issues the fishery
faces. Much of what was found follows the template of other tropical reef fisheries around the world,
including the use of traditional fishing methods and increased fishing pressure due to population
expansion and local development.
Diego-Suarez Bay is clearly an important and well-used resource for local villages. Fishing is the
principal use of the bay and a number of issues associated with the fishery have been identified. Fishing
in the bay clearly has an impact on the fish themselves, as well as on the environment. The fishery is not
in a bad state although through various management strategies it could become more productive.
The scope for using this study as a guide or resource for the future management of the bay is feasible.
Further investigation, of which some is suggested in this study, would help to provide a greater
information base to assist with the creation of suitable and accurate management strategies.
21

6 References
Adam, M.S., Anderson, R.C., and Shakel, H., 1997. Commercial exploitation of reef resources: examples
of sustainable and non-sustainable utilization from the Maldives. Proceedings of the eighth international
coral reef symposium. Smithsonian Tropical Research Institute. Balboa, Panama, pp 2015-2020.
Ashworth, J.S., and Ormond, R.F.G., 2005. Effects of fishing pressure and trophic group on abundance
and spillover across boundaries of a no-take zone. Biological Conservation 121: 333-344.
Billé, R., and Mermet, L., 2002. Integrated coastal management at the regional level: lessons from
Toliary, Madagascar. Ocean and Coastal Management 45: 41–58.
Choat, J.H., and Robertson, D.R., 2002. Age-based studies. In: Coral reef fishes: dynamics and diversity
in a complex ecosystem, ed. P.F. Sale, pp. 57-80. San Diego: Academic Press.
Colblentz, B.E., 1997. Subsistence consumption of coral reef fish suggests non-sustainable extraction.
Conservation Biology 11: 559-561.
Connell, S.D., Samoilys, M.A., Lincoln Smith., M.P., and Leqata, J., 1998. Comparisons of abundance of
coral reef fish: Catch and effort surveys vs. visual census. Australian Journal of Ecology 22: 579-586.
Dalzell, P., 1998. The role of archaeological and cultural historical records in long-range coastal fisheries
resources management strategies and polices in Pacific Islands. Ocean and Coastal Management 40: 237-
252.
Donohue, M.J., Boland, R.C., Sramek, C.M., and Antonelis, G.A., 2001. Derelict fishing gear in the
North-western Hawaiian Islands: Diving surveys and debris removal in 1999 confirm threat to coral reef
ecosystems. Marine Pollution Bulletin 42: 1301-1312.
Frontier-Madagascar (2003) Webster, C.L., Fanning, E., Hémery, G. and Woods-Ballard A.J. (eds)
Marine Biodiversity Training Manual. Frontier-Madagascar Environmental Research Report 3. ISSN
1479-120X Society for Environmental Exploration, London and L’ Institut Halieutique et des Sciences
Marines, Toliara,
Frontier Madagascar (2007) Browne N.B, Markham, H, Fanning E & Weaver D (Eds). A Proposed
Marine Management Strategy: Diego Suarez Bay. Frontier-Madagascar Environmental Research Report
16. Society for Environmental Exploration, UK and L’Institute Halieutique et des Sciences Marines,
Toliara.
Gedamke, T., Hoenig, J.M., Musik, J.A., Dupaul, W.D., and Gruber, S.H., 2007. Using demographic
models to determine intrinsic rate of increase and sustainable fishing for elasmobranchs: Pitfalls,
Advances, and Applications. North American Journal of Fisheries Management 27: 605–618.
Grandcourt, E.M., Al Abdessalaam, T.Z., Al Shamsi, A.T., Francis, F., 2006. Biology and assessment of
the painted sweetlips (Diagramma pictum (Thunberg, 1792)) and the spangled emperor (Lethrinus
nebulosus (Forsskal, 1775)) in the southern Arabian Gulf. Fishery Bulletin 104: 75-88.
Hawkins, J.P and Roberts, C.M., 2004. Effects of artisanal fishing on Caribbean coral reefs. Conservation
Biology 18: 215-226.
Keenleyside, M.H.A., 1997. Development of research on fish behaviour as part of fisheries science in
Canada. Canadian Journal of Fisheries and Aquatic Science 54: 2709–2719.
Koslow, J.A., Aiken, K., Auil, , S, and Clementson, A., 1994. Catch and effort analysis of the reef
fisheries of Jamaica and Belize. Fisheries Bulletin 92: 737-747.
22

Laroche, J., Razanoelisoa, J., Fauroux, E., and Rabenevanana, M.W., 1997. The reef fisheries surrounding
the southwest coastal cities of Madagascar. Fisheries Management and Ecology 4: 285-299.
Lindholm, J.B., Auster, P., Ruth, M., Kaufman, L., 2001. Modeling the effects of fishing and implications
for the design of marine protected areas: juvenile fish responses to variations in seafloor habitat.
Conservation Biology 15: 424–437.
Lieske, E., and Myers, R., 2001. Coral reef fishes. Princeton University Press.
Mangi, S.C., and Roberts, C.M., 2006. Quantifying the environmental impacts of artisanal fishing gear on
Kenya's coral reef ecosystems. Marine Pollution Bulletin 52: 1646-1660.
Matsuoka, T., T. Nakashima, and N. Nagasawa. 2005. A review of ghost fishing: scientific approaches to
evaluation and solutions. Fisheries Science 71: 691-702.
McClanahan, T.R., Kamukuru, A.T., Muthiga, N.A., Yebio, M.G., Obura, D., 1996. Effect of sea urchin
reductions on algae, coral, and fish populations. Conservation Biology 10, 136–154.
McClanahan, T.R., and Mangi, S., 2000. Spillover of exploitable fishes from a marine park and its effect
on the adjacent fishery. Ecological Applications 10: 1792–1805.
Munro, J.L., 1983. Caribbean coral reef fisheries. Studies review 7. International Centre for Living
Aquatic Resource Management (ICLARM), Manila, Philippines.
Munro, J.L., 1996. The scope for tropical reef fisheries and their management. Pages 1-14 in N.V.C.
Polinin and C.M Roberts, editors. Reef fisheries, Chapman and Hall, London.
Myers, R.A., Hutchings, J.A., and Barrowman, N.J., 1997. Why do fish stocks collapse? The example of
cod in Atlantic Canada. Ecological Applications 7: 91-106.
Pauly, D., 2008. Global fisheries: a brief review. Journal of Biological Research-Thessaloniki 9: 3–9.
Roberts, C.M., Bohnsack, J.A., Gell, F., Hawkins, J.P., and Goodridge, R., 2001. Effects of marine
reserves on adjacent fisheries. Science 294: 1920–1923.
Tietze, U., Groenewold, G., and Marcoux, A., 2000. Demographic change in coastal fishing communities
and its implications for the coastal environment. FAO Fisheries Technical Paper - T403, pp 403.
Tundi A., 2000. Viewpoint effects of fisheries on marine ecosystems: a conservationist’s perspective.
ICES Journal of Marine Science 57: 761–765.
Watling, L., and Norse, E.A., 1998. Disturbance of the seabed by mobile fishing gear; a comparison to
forest clear cutting. Conservation biology 12: 1180-1197.
Wells, S.M., 1997. Giant clams: status, trade and mariculture, and the role CITES in management. World
Conservation Union, Gland, Switzerland, and Cambridge, United Kingdom.
Woods-Ballard, A.J., Chiaroni, L.D. and Fanning, E. (eds), 2003. Fin-fish resource use: artisanal fisheries
of Beheloka. Frontier Madagascar Environmental Research Report 11. Society for Environmental
Exploration, UK and L’Institut Halieutique et des Science Marines, Toliara.
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Appendices
Sample Questionnaire Fisherman Diego Suarez Bay
Personal details
Name: Occupation:
Age: Education level:
Place of residence: Fishing area:
Married/Single: Years of fishing:
Number of children: Other sources of income:
Bay
1. In what sectors of the bay do you fish?
2. How long have you been fishing in that area?
3. Who else is fishing in that area?
4. Do you fish in any other areas?
5. What is your main interest in the bay?
Fishing as a way of living/Fishing to feed family/Way of transport/Moral obligation/Aesthetic
value/Religious value/Conservation for future use/Gaining money from tourists
Fishing practices
6. What fish species do you target?
Fish:
Sweetlips/Emperors/Groupers/Jacks/Trevallies/Rabbitfish/Goatfish/Parrotfish/Wrasse//Snappers/Fusilier
s/
Surgeonfish/Milkfish/Tuna/Shark/Sardine/other
Other:
Octopus/Sea cucumbers
7. Why do you target these fish? Common specie s/good money/gear/good to eat/other
8. How many days a week do you fish? 1 - 2 - 3 - 4 - 5 - 6 - 7
9. On what days do you fish? Mon - Tues - Wed – Thurs – Fri – Sat - Sun
10. How many hours do you spend fishing on each day? 1 - 2 - 3 - 4 - 5 – 6 - 7 -8
11. In what months do you fish in Diego Bay? Jan - Feb - Mar - Apr - May - Jun - Jul - Aug - Sep - Oct -
Nov - Dec
12. What kind of fishing gear do you use? Fishing net - Seine net - Spear - Hook and line - Poison -
Other…
13. Did you change your fishing techniques in the years that you have been fishing? If yes, what
changed?
14. Do you throw fish back in the sea? Yes - too small/not good to eat/not valuable/other - No
15. How many kg of fish do you catch on average per catch? 0-25kg / 25-50kg / 50-75kg /n >75kg
16. How often do you sell your catch? every day/every couple of days/weekly/depends on catch size
17. Where do you sell your fish?
18. Has your catch size decreased - stayed the same - increased?
19. If catch size has changed, why do you think this happened?
20. Has fish abundance decreased - stayed the same - increased?
21. Has average fish size decreased - stayed the same - increased?
22. What would you do to increase your fish catch? And what area would you go to increase your fish
catch?
23. Does fishing have an impact on the environment underwater?
24. Are there any fady’s that apply to fishing?
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25. What should be done to keep enough fish for this and future generations? Indicate to what extent you
agree or disagree with a statement.
I agree strongly I agree Neutral I disagree I disagree strongly
1 2 3 4 5
I. Only fish in specific areas
1 2 3 4 5
II. Use fishing nets with mesh size bigger than 4 cm
1 2 3 4 5
III. Communities should work together to control the size of fish catches
1 2 3 4 5
IV. Deforestation in coastal areas should be stopped
1 2 3 4 5
V. Only catch large fish
1 2 3 4 5
VI. Nothing specific, there is enough fish for this and future generations in the sea
1 2 3 4 5
VII. Only go out fishing on certain days
1 2 3 4 5
VIII. Each fisherman should decide himself how much fish he catches
1 2 3 4 5
IX. Pray for more fish or ask ancestors
1 2 3 4 5
X. The government in Diego should control the size of fish catches
1 2 3 4 5
XI. Eat less fish
1 2 3 4 5
XII. Only catch certain fish species
1 2 3 4 5
XIII. The head/chief of the village should control the size of fish catches
1 2 3 4 5
XIV Get more tourists to the bay as an alternative source of income
1 2 3 4 5
25