Limited data already show further drop in abundance of round sardinella
Round sardinella is the most important species of small pelagics for the national fleets both in Mauritania and in Senegal. Given the importance of the stock for job creation and food security, and the serious threats to which it is exposed at the moment, it is surprising that the two main fishing nations (Mauritania and Senegal) have so far been negligent in collecting sufficient scientific data for stock assessment. Sampling of artisanal catches in Mauritania has been at a very low level in 2016 and 2017, despite strong recommendations from the FAO Working Group on Small Pelagic Fish in Northwest Africa to improve the situation. For Senegal, little information is available on the actual level of sampling.
Although only limited data on round sardinella are currently available, all these data point to a further decline of the stock. The catches of round sardinella in Mauritania decreased from 292,000 tons in 2016 to 172,000 tons in 2017; a drop of 41%. But these figures may have been affected to some extent by misreporting. As a result of new regulations concerning the maximum quantity of round sardinella that may be used for fishmeal (10,000 t/year/factory), some fishmeal plants have probably reported part of the landings of sardinella as bonga. Indeed, the reported catch of bonga increased by about 40,000 t in 2017, and it is likely that this increase in reality consisted of round sardinella. However, even if we make allowances for this misreporting, the catch of round sardinella in 2017 still dropped by 80,000 tons compared to 2016…
For Senegal, on the other hand, catches of round sardinella seemed to have remained stable in 2017 compared to 2016, around 190,000 tons. However, these figures do not include the catches used for fishmeal, therefore the actual landings of round sardinella in Senegal in 2017 may have been higher than in 2016. It should be noted, however, that according to fishermen’s organisations, round sardinella were very scarce in the waters north of Dakar during the 2017-2018 season. The high catches of round sardinella in 2017 were presumably taken south of Dakar, and must have consisted mainly of young fish.
In Mauritania, the catch per unit of effort (CPUE) in the canoe and coastal purse seine fishery substantially dropped between 2016 and 2017. The CPUE of the Russian-type trawlers in Mauritania also showed a strong drop in 2017. This sharp drop in CPUE is a strong indication that the decline of round sardinella catches in 2017 was due to a drop in fish abundance, and not to a reduction of the fishing effort.
An acoustic survey by the Norwegian R/V Dr Fridtjof Nansen in May-July 2017 in the area from Morocco to Senegal produced the lowest stock estimate for round sardinella in NW Africa since the start of these surveys in 1995. In summary, it may be concluded that all available information points to a substantial drop in abundance of round sardinella in 2017.
The effect of the fishmeal industry
During a meeting with representatives of Senegalese fishermen’s organisations CONIPAS, FENAGIE and APRAPAM in January 2018, all the organisations expressed their concern about decreasing round sardinella catches, particular in the area north of Dakar (the “Grand Côte”). According to these fishers organisations, many fishermen were leaving the industry because of low catches. In fact, the fisheries in Mauritania and Senegal exploit different components of the round sardinella stock. It is known that the Senegalese fishery south of Dakar mainly exploits the younger fish, whereas the fishery in Mauritania and in the northern part of Senegal depends on the adult fish that perform the seasonal migration from Senegal to Mauritania and Morocco. A depletion of the adult stock component will therefore have a stronger impact on catches in Mauritania and northern Senegal than on catches in the south of Senegal.
Data collected in Mauritania over the past 19 years indicate that fishing mortality has been gradually increasing. In the period 1999 – 2013 this was due to the exploitation of sardinella by foreign trawlers in Mauritania, and probably also by a gradual increase in effort by the Senegalese artisanal fleet. After 2012, the place of the foreign trawlers in Mauritania was taken over by the fishmeal industry. The development of this industry in Mauritania has been well documented. More recently, a fishmeal industry also developed in Senegal and Gambia. For these countries, little or no information is available on the amounts of fish used for fishmeal nor on their species composition. Most likely, the bulk of the catches used for fishmeal consisted of sardinella (round and flat). This was echoed by a representative of the Seneglese women engaged in the sardinella smoking industry (“transformatrices”), who explained that their activity was threatened because of the competition from fishmeal factories that bought all the sardinella.
Whereas the effort by artisanal fleets in earlier years was restricted by the demand from the human consumption market, this restriction no longer exists at the moment. The fishmeal plants can absorb large quantities of fish, which stimulates artisanal fishermen to increase their effort. Mauritanian fishmeal plants have even brought in a completely new fleet of efficient Turkish purse seiners to supply them with fish. Senegalese fishermen from Casamance are now landing catches at fishmeal plants in Gambia. Sometimes these landings are so big that even the fishmeal plants cannot absorb them. As a result, considerable quantities of sardinella have to be dumped at sea or on the land.
To conclude, the limited data available show that the stock of round sardinella in North Western Africa has been further reduced in the most recent years by an increase of fishing effort. The main cause of this increased effort is the development of a fishmeal industry in the region. This development has increased the outlet possibilities for the artisanal fleets, and even brought in an entire new fleet in Mauritania to catch the fish for the fishmeal factories.
The older age groups in the round sardinella population have been depleted and the fishery now depends largely on the youngest fish. Fleets that exploit the adult part of the population, such as the ones in northern Senegal and in Mauritania, are hardest hit by the absence of older fish. The overexploitation of the stock presents a serious threat for the employment of many thousands of fishermen and women fish smokers in Senegal, and for the food security of millions of people in West Africa.
The assessment of the stock is seriously hampered by the lack of sampling in Mauritania and by the poor data provided by Senegal to the FAO working group. Considering the social and economic importance of sardinella to Mauritania and Senegal, it is absolutely vital that appropriate investment is made in research on small pelagics, round sardinella in particular, in both countries, and in cooperation between the countries, in order to get the best scientific data possible.
*Ad Corten is coordinator of the Dutch/Mauritanian cooperation in fisheries research