The fifth meeting of the FAO Working Group on the Assessment of Small Pelagic Fish off Northwest Africa was held in Nouadhibou, Mauritania, from 26 April to 5 May 2005. The meeting continued to focus on data quality and on the analysis of trends in the basic data (landings, catch, effort, abundance, length and age distribution) and trends in the fishery independent survey data. The structure of the report is the same as that of the previous Working Group report (FAO, 2004), with the addition of two chapters, one on bonga (Ethmalosa fimbriata) and one on anchovy (Engraulis encrasicolus). A separate section is devoted to each of the main groups of species (sardine, sardinella, horse mackerel, chub mackerel, bonga and anchovy). For each of these, standardised information is given on stock identity, fisheries, abundance indices, sampling, biological data, assessment, management recommendations and future research. In the absence of reliable length and/or age compositions, the Working Group used production models for all stocks. The results of the assessments indicate that the sardine stock in Zone C is not fully exploited and the Working Group hence noted that the total catch level may be temporarily increased but should be adjusted to natural changes in the stock. A constant monitoring of the stock abundance and structure, by scientific surveys, independent from catch data, should be ensured, to detect unanticipated changes that may require urgent management measures. As regards the central stock of sardine (Zones A+ B), it is recommended not to increase catches above the average level of the last five years (600 000 tonnes). The stock of round sardinella was found to be fully exploited and it was hence recommended not to increase catches of sardinella above the current level of 400 000 tonnes (2004). As a precautionary approach, the Working Group recommended not to increase catches above the average level of the last five years for the horse mackerels (80 000 tonnes for Trachurus trachurus and 170 000 tonnes for T. trecae) and not to increase catches above the 2004 level for chub mackerel (220 000 tonnes). For bonga the Working Group recommended as a precautionary measure that the catch level should not exceed the average over the last five years (42 000 tonnes) and for anchovy the catch level should not exceed the average over the last three years (160 000 tonnes). In formulating the results of the assessments, the Working Group noted that it lacked a set of uniform reference points and management objectives for all stocks in the area. The Group noted that the selection of appropriate reference points required more time than was available during the meeting. It was therefore decided that some members will look further into this problem, working by correspondence, and present a working paper at the 2006 meeting. At that meeting the Working Group will attempt to agree on a common policy concerning the way it presents its management advice for the various stocks.