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(Madagascar) Spatial analysis of resource use by octopus fishers in SW Madagascar

Student requirements

  • Strong swimmer, water confident.

  • Familiar with reef flat environments.

  • Able to live in basic conditions.

  • 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 led 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 in the region and will serve to establish whether the current fishing effort is sustainable.  

This project aims to provide detailed information on the issue of octopus catchability; whether fishers randomly search the reef or if octopus have a known preference for particular areas. The project will also generate detailed information on the fishing activity of artisanal octopus fishers and generate an accurate picture of fishing effort. Several attempts have been made to quantify fishing effort along the southwest coast and it is hoped that a sample of accurate measurements collected with the method detailed below can be used as a proxy for CPUE calculations along the coast.

Methods

A preliminary study was trialled based in the village of Andavadoaka in August/September 2011. Using this tested methodology the student will collect GPS tracks of artisanal octopus fishers during their usual fishing trip. Students will follow a selected fisher for the whole survey period. A translator may be required to facilitate this selection but it is hoped that after the initial contact the student will be able to communicate with the fisher. The student should not change the behaviour of the fisher by their presence so it is almost better if they cannot communicate with the fisher!

The following data will be recorded and generated:

  1. GPS track: a GPS track of the course the fisher takes on a fishing trip will allow us to tackle the question of whether fishers search randomly for octopus, or whether they follow a set route across the reef flat to target areas where octopus are preferentially located.

  2. GPS log of hole location: over the course of the 2 or 3 tide survey period evidence of octopus recruitment into fished holes may be evident.

  3. Fisher Activity Log: the student will record every activity the fisher undertakes along with the time of each activity change. It is likely that activities will include: transit to/from site, active searching, hole investigation, octopus catching.

  4. Fisher CPUE: the student will be equipped with a portable balance and will weigh and sex each octopus caught by the fisher in the course of the trip. This will allow a true measure of catch per fisher per hour to be generated.

The following villages (listed from North to South) are recommended for surveys in order to build up a complete picture of the variations in fishing style throughout the southwest coast:

  • Morombe

  • Andambatihy

  • Andavadoaka

  • Salary

  • Ifaty/Mangily, Bay of Ranobe,

  • Ankiembe, Grand Recif de Tulear

  • Anakao, Nosy Ve

  • Itampolo

  • Ambohibola

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

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 preliminary surveys conducted in Andavadoaka the data generated here will allow students to accurately assess the CPUE of local octopus fishers. Data will be generate on octopus catchability and octopus fisher search patterns. Data may also identify octopus recruiting to holes where octopus were previously caught. 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.


 

 

 

 


Independent research projects (2013-2014) - Madagascar

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