Assessing best methods to survey spawning aggregations

Type: 
Master Thesis subject (30 ECTS)
programme: 
EMBC+
1. Description of the project: this thesis will be included in the postdoc Project of Barbara Horta e Costa, starting in December 2015. The title of the project is ‘Linking the ecological and evolutionary roles of selective fisheries and MPAs: implications for management’. The main objective of this study is to assess fisheries/protection induced selective pressures on fish behaviour and reproductive strategies of Diplodus sargus and Dicentrarchus labrax, priority species in Europe and for the Portuguese monitoring program under the Marine Strategy Framework Directive (MSFD/DQEM), in a multiple-use MPA (the Algarve region of the marine park PNSACV, South West coast of Portugal). For that, one of the specific goals is to assess time, location and duration of spawning aggregations of those species. Other specific goal is to assess density, biomass and behavioural patterns related to key spawning aggregations. 2. Methods: we will evaluate the location and extension of spawning aggregations, estimate density, size and biomass, and individual behavioural patterns and characterize spawning habitats through underwater drop cameras (wide-angle). Therefore, the duration of recording of each replicate, the number and extent of replicates, if cameras are baited of not, will have to be tested in order to achieve the best method to assess spawning aggregations of our study species (D. sargus and D. labrax) in our study area. Spawning aggregations have been understudied, especially in regions similar to ours, and before following a specific method (although already tested for other species elsewhere) we need to assess which is the best for our particular case and species. Furthermore, underwater visual surveys and image records with ROV (remotely operated vehicle) will be conducted to validate data obtained through the drop cameras. 3. Field work requirements: An intensive field work campaign is expected when spawning aggregations are detected in the region (which are usually in January-February). Approximately 2 weeks are expected to test methods in the field. Scientific diving skills are required. The student will have the opportunity to test and contact with a variety of methods and techniques; will be working with an experienced research team and will be working in the field within a beautiful and still ‘wild’ marine park. We are looking for a motivated and hard-working student aiming at conducting such research (in a short period) to achieve the best results and to write an interesting thesis with potential for publication. 4. Data analysis: Images will be viewed in depth after the field work campaign, to assess size and density of fish in videos and compare data between methods tested in order to assess the best duration for video recording and the number of replicates and transects to attain an adequate sample size (N) for the characterization of spawning aggregations. Also, a comparison of results will be conducted between baited and non-baited cameras. 5. Expected targets: this study is expected to result in a publication in an international peer-review journal. Example of title: “How to assess spawning aggregations of demersal fish species using drop cameras”. Suggestion of journal: JEMBE
prerequisites: 
Scientific diving skills are required.
Number of students: 
1
academic year: 
2015-2016
Contact person email: 
contact person first name: 
Barbara Horta e Costa
Other people involved: 
Jorge M.S. Gonçalves Karim Erzini
Institutes Involved: 
Reference Number: RP-36842