J. Rodríguez-Gutiérrez

FishPi is a pilot project financed through an European grant (MARE/2014/19) aiming to strengthen regional coordination in the area of fisheries data collection. This project includes four case studies, one of which aims at analyzing alternative sampling plans for fisheries operating on Northern & Southern hake stocks. The case study analyzes a variety of sampling design scenarios, from Simple Random Sampling to combinations of stratified sampling designs (by country, by port, by quarter…), using anonymised landings data from logbooks and sales notes (2013-2014). The results were compared regarding bias and precision to evaluate the best approach. The most precise estimates of total catch were obtained in scenarios stratified by port and, secondly, by port and country and by port and quarter. The general conclusion was that regional sampling designs stratified by port provided improved precision in this fishery. Apart from statistical considerations, this conclusion was also discussed under other points of view to give a feasibility perspective showing that coverage by country, and also by domain (stock), would be compromised if regional design is simply based on statistical analyses. Efficiency and precision of sampling were found to be highly sensitive to the sampling assumptions and in general countries with smaller contributions to overall landings of hake would see their sampling plans reduced, compromising other requirements for advice such as those related to other stocks or local management measures established by National governments. Hence further analyses are being considered that integrate biometrics, cost-benefit aspects, and concurrent or single-stock sampling strategies.

The overarching objective of the FishPi project is to strengthen regional cooperation in the area of fisheries data collection. The role of every case study within the project is to bring together the countries with the most involvement in the fisheries selected to coordinate and cooperate in the search of a probabilistic regional sampling design. To this aim, case study 4 (CS4) is focused in the Northern and Southern Hake stocks.
\nThe work done in the case study include the description of the fishery at a regional level, the compilation of the present national sampling activity, the compilation of the logbooks and/or sales notes from 2013 and 2014 –to have a single regional data set of all trips of interest in the region– and different runs of simulations to test the selected sampling scenarios and stratifications. Finally, an objective evaluation of the performance of these regional designs is expected to understand the changes needed compared to the present situation.
\nThis document presents the progress done in this case study, from the data compilation to the simulations, documenting the different steps taken and allowing an understanding of the pending tasks.