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

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.
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