Acronym SEA
Category
Fisheries
Title Stock evaluation of abalone: towards a sustainable fishery Programme National Programme
Instrument (FP6)
Contact Type (FP7)
Strand (Interreg)
NA
Theme (FP7)
Activity Area (FP6)
Regional Area (Interreg)
Action (COST)
NA
Specific Programme (FP7)
NA
Funding source National Coordinator Gustavo Oliveira de Meneses Martins Coordinator email gmartins@uac.pt
Coordinator institution
UAC-CIRN - University of the Azores; Center for Research in Natural Resources (Portugal)
Institutions involved
FRCT - Regional Fund for Science and Technology of the Azores (Portugal) ,
Start year 2012 End year 2015 Funding (€) € 38,465 Website http://gba.uac.pt/research/projects/ver.php?id=33 Summary Make an evaluation of the stock of Haliotis tuberculata in the Azores. This species, despite being economically important in other regions, it yet to be exploited in the Azores. However, there is evidence that H. tuberculata is already starting to be exploited here. This allows us to collect biological data when stocks are still relatively virgin, unlike for most fishery research.
As the number of collapsed stocks scales up, there is an increasing social and economic demand to foster for alternative sources of commercial resources. Abalone species are highly regarded as seafood and are commercially harvested in many parts of the world. As with numerous other populations, many abalone stocks have been severely depleted due to overfishing. In the Azores, however, abalone has not been traditionally collected, but there is anecdotal evidence that abalone fishery may soon become a reality, especially because the stocks of limpets, a locally traditional shellfish, are severely depleted (Martins et al. 2008, Martins et al. in press). The key aim of this project is to make a preliminary evaluation of the conditions for the sustainable commercial harvesting of abalone (H. tuberculata) in the Azores. Specifically, we will examine factors affecting the distribution of abalone populations, its reproduction (seasonality, sex-ratio), growth, birth and death rates. Collecting such information when stocks are still in its pristine state is paramount in order to accurately assess the impact of potential disturbances such as fishing. In addition, this information will be used to create a model of population dynamics, providing a tool that can be used to assess the sustainability of different levels of fishing effort. We will investigate the abundance and patterns of distribution in abalone populations on the Island of São Miguel. The literature suggests that abalones have a spatially heterogeneous distribution aggregating in some locations and are often associated with key features of the substratum (e.g. cracks, boulders). Non-destructive surveys (following the recommendations of McGarvey et al. 2008) will be done at locations around São Miguel within habitat types stratified according to depth, substrata and wave-exposure. In each of these locations, transects will be used to estimate the numbers of individuals (density). In addition, all animals will be measured to the nearest mm using Vernier callipers (shell length) to estimate the size structure of populations. Surveys will be repeated 2 times in order to investigate patterns of temporal variability in the abundance and size of abalones. These data will be integrated with previous mapping work done by the team in different habitat types around São Miguel to provide a general estimation of the size of abalone populations on this island. A number of individuals will be collected each month for two years on at least two locations. The number collected will be a compromise between the necessity to have sufficient numbers for statistical purposes and the need to keep low levels of disturbance to the populations examined. Collected animals will be inspected for size, weight, gender and gonad status. This information will be used to estimate the main biological parameters such as recruitment, growth rates and reproduction. Growth rates will be estimated by constructing Ford-Walford plots of initial abalone length against the growth over 1 year period of marked individuals. Gonad maturation and timing of spawning will be examined using two alternative but complementary techniques: the gonad-bulk index (GBI) (Hahn 2000) and more advanced histological techniques (see Cúrdia et al. 2005 for example). Abundance, growth, and reproduction data will be combined to produce a biomass dynamic model of the unfished stock. This will be an important stock assessment tool once (and if) the commercial operations start because it will allow the production of estimates of stock sizes and catch rates relating mainly to the maximum sustainable yield (MSY) reference point (Hoggarth et al. 2006).
Keywords
Sustainability;
Population dynamic;
Shellfish;
Stock assessment;
Biology;
Abalone;
Mollusc;
Gastropod;
Marine Region
40
Azores Grounds (27.Xa, 27.Xb)
1
Marine Region Map
