Report on data collected on small pelagics and environmental forcing on the west coast of Africa

Fisheries of small pelagics, namely sardine (Sardina pilchardus), chub mackerel (Scomber colias) and European anchovy (Engraulis encrasicolus) in Morocco and Mauritania are extremely important from the socio-economic perspective. They account for the largest biomasses landed and contribut to the national economies through employment and exports of canned products, fish meal and fish oil, while also being a major source of protein for national consumption. Stocks of small pelagics in upwelling regions are characterised by strong variability in recruitment and abundance, with environmental drivers playing a key role. Most stock assessment approaches do not take into account environmental variability or interactions between species, in an ecosystem context. Understanding the drivers of fluctuations in the variability of small pelagics would contribute to improved management and conservation. For all the above reasons, the FarFish project is awarding significant efforts towards estimating population trends of small-pelagics provided by stock assessment models to find the link with environmental variables. The work is broken into two tasks i.e. the data collection part (WP2) and the modelling part (WP6). This document reports on the WP2 task, which includes compiling the data input for different models, like life history parameters and time series of catches, landings, effort, indices of abundance, as well as finding the sources to get different environmental variables.

This deliverable reports on the biological and fisheries data compiled for the three key small pelagic species. Time series suitable for modelling were compiled from a number of sources, national and international as well as fisheries dependent and fisheries independent (research surveys). Life history parameters (growth, weight-length relationships) were also compiled from different sources. Catch data time series are available since the 1970s, with reconstructed time series (Sea Around Us project) extending the time series back to 1950. Fishing effort data is available from the early 1990s, with shorter time series of abundance indices available from research surveys, for Morocco. Time series of fishing effort for Mauritania are however lacking.

Together with time series of environmental variables, the data compiled will feed WP6 where new approaches and models will be applied to gain a better understanding the population dynamics of the three small pelagics and contribute to improving management. WP6 will fit stock assessment models for these data. Resulting estimates will then be contrasted with different environmental variables and links found will contribute to gain a better understanding of the population dynamics for these three small pelagics. Disentangling the environmental effect over the population could also be further used to enhance management practices.