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(Madagascar) An assessment of the ecological characteristics of reef habitat most suitable for octopus; does reef flat quality alter the success of the short term fisheries closures?

Student requirements

  • Strong swimmer, water confident

  • Familiar with reef flat environments

  • Able to live in basic conditions

  • Basic French language skills or willingness to learn basic Malagasy

  • Independent and happy to live and work alone with no fellow English speakers during the field period

Background

Recent commercialisation of octopus fisheries in the Andavadoaka region has lead to increased fishing pressures on octopus and anecdotal reports suggest that both numbers and sizes are declining.

Since September 2004, details of octopus catches have been recorded by a network of ‘sous collectors’, who purchase the octopus directly from the fishers. These sous collectors are affiliated with data collectors who are employed by Blue Ventures in 18 villages all along the southwest coast as part of the larger stock assessment project run in partnership with the IHSM this is the first stock assessment for octopus and will serve to establish whether the current fishing effort is sustainable.  

Since the first trial closure of areas of octopus reef flat to fishing for short periods the octopus temporary closure project has developed. Today a network of closures occurs across up to 450 km of coastline from Morombe to Ambohibola. Currently villages are able to select whichever site they want as a reserve and are under no obligation to have a reserve at all. Anecdotal reports of opening day catches suggest that some reserves are more successful than others. The reasons for this are currently unknown. Technical support provided by Blue Ventures may help guide communities to select the most suitable sites for temporary closure.

This project aims to provide some baseline ecological data on reef flat areas selected as temporary closures, and to assess which ecological characteristics of reef flat areas octopus prefer.

Methods

Similar studies have currently conducted in 2010 looking at 18 sites in Velondriake and 6 sites in Beheloke. Using this tested methodology the student will conduct habitat assessments of a selection of the most popular sites from new villages distributed along the southwest coast conducting the following methods:

  1. Rugosity. Standard chain methodology is used over 50m

  2. LITs 10-50m replicates with the following categories dead coral, microalgae, sand, rubble, massive coral, encrusting coral, soft coral and sea grass

  3. Belt transects for octopus hole abundance 3 x 10-50m. Any holes found during count are categorised, measured and assessed for presence or absence of octopus.

The following villages (listed from North to South) are recommended for future surveys in order to build up a complete picture of any changes in reef flat characteristics:

  • Salary
  • Ifaty/Mangily, Bay of Ranobe
  • Ankiembe, Grand Recif de Tulear
  • Anakao, Nosy Ve
  • Itampolo
  • Ambohibola
  • Morombe

 

NGO staff are present in some of these villages and may be able to provide some support in the field (BV, Reef Doctor, WWF, WCS). However, a translator should be hired in Toliara and students should assume that they will have no direct support in the field. In villages where phone reception is available students can contact BV staff with any questions arising from the work. However, it is noted that some of these villages do not have phone reception.

 Budget

Exact budget will depend on the survey village selected but costs will include:

  • Transport to field site

  • Translator

  • Per diems to local octopus fishers to act as guides and surveyors

  • Transport out to reef sites where access is by boat

  • Food and accommodation while in the field

Timings

This project can be undertaken at any time during the year. However it should be noted that surveying is only possible over the spring (and possibly neap tide periods depending on the village) as octopus sites are inaccessible at other times. Thus surveying should be timed to coincide with spring tides.

Expected Results

Building on the results of the surveys in the Velondriake region and in the village of Beheloke, these ecological data will contribute towards the understanding of the ecological characteristics of successful octopus fishing sites. Access to the octopus catch data set for the selected village will allow the student to calculate CPUE’s per site and relate habitat variables to monthly CPUE’s. Data will be added to the master southwest habitat database for larger scale analyses at a later date.

For more information please contact the London office.


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