There is a tendency to consume more large fish than small fish. However, favoring small fish has more than one benefit for human health and that of ecosystems. Fishing for small fish also has less impact on ecosystems. The consumption of fish benefits from a very positive image among European consumers, riding particularly on the wave of what is called the Healthy Food trend and the popularity of Japanese cuisine. Fish is perceived as a nutritious food, low in fat, rich in micronutrients, and whose environmental impact associated with its production is relatively low compared to meat. While consumers generally distinguish very precisely the species originating from the meat they consume (chicken, beef, pork...), fish is generally considered as a whole, regardless of the species concerned. Whereas fewer than a dozen terrestrial animal species are commonly consumed for their meat, the so-called "common" fish include several dozen species. Among the most consumed fish in Europe, the large species, such as salmon, cod (common name for haddock), or tuna (which actually refers to several species grouped under this generic name), take the lion's share (of the sea), representing more than a quarter of the total quantity consumed. On the contrary, the small species, grouped under the term of "small pelagic fish" (sardines, anchovies, mackerels, herring...) represent a much smaller quantity. Whereas large fish generally benefit from an image of nutritious, healthy, and natural food among consumers, the perception of small pelagic fish is rather that of a food that is certainly tasty, but generally more traditional, and to be honest, a bit old-fashioned. Generally, all fish are excellent sources of nutrition, and although their composition in nutrients varies from one species to another, all are good sources of macro and micronutrients, among which iron, zinc, calcium, selenium as well as polyunsaturated fatty acids omega-3. These compounds are essential for the proper functioning of the body (immune system, nervous system development, cellular exchanges), and deficiencies can lead to serious dysfunctions at the nervous level, which can go as far as the development of neurodegenerative diseases or cancers. Among the most interesting omega-3s from a metabolic point of view, the docosahexaenoic acid (DHA) and the eicosapentaenoic acid (EPA) are almost exclusive to marine products. Synthesized by microalgae and transferred along the food chain via aquatic organisms, humans depend almost exclusively on marine products to acquire these compounds. If all marine fish contain them in notable quantities, the fish of the Clupeiformes order, which include sardines, anchovies, and herring, are known to be the richest in EPA and DHA of all fish as well as in calcium and zinc. Thus, among the hundreds of fish species consumed worldwide, small pelagic fish are certainly those that provide the most nutritional advantages. They thus fully contribute to nutritional security. This issue is particularly relevant in the intertropical regions, where a significant part of the population remains exposed to food insecurity. In West Africa, for example, it is estimated that food insecurity affected 61.6% of the population during the period 2022-2024. In this context, the consumption of fish, and more generally of seafood, represents an important potential to achieve the food security objective set by the United Nations in 2015 as one of the 17 major Sustainable Development Goals at the global level. Despite their high nutritional value, fish are also subject to the various pollutions affecting the marine environment and which can accumulate in their flesh, representing in fine a potential risk associated with their consumption. Two mechanisms explain this accumulation: bioaccumulation, a phenomenon by which pollutants that organisms are not able to eliminate accumulate in their tissues; and bioamplification, a phenomenon by which a predator accumulates the pollutants present in the flesh of its prey. Thus, both due to bioamplification and bioaccumulation, large fish, which live longer and are generally located at the top of food chains, are theoretically the most likely to present contamination levels associated with health risks for pollutants capable of being bioamplified. The most striking example is that of mercury, which is subject to these two mechanisms. It has thus been observed in certain large marine predators that mercury concentrations exceed all international standards. In the Saint-Laurent estuary in Quebec (Canada), the carcasses of belugas stranded are thus treated as toxic waste, outside of the usual butchering circuits. This general pattern, which well describes how certain pollutants such as mercury accumulate more in large fish than in small ones, is however not valid for all pollutants. Fish, like all marine organisms, are indeed subject to a cocktail of pollutants (heavy metals, persistent organic pollutants, micro and nano-plastics), which have diverse origins and contamination pathways, and for which fish have detoxification capacities that vary depending on the pollutant, and especially on the species concerned. Beyond these general mechanisms, it remains nevertheless important to mention that one of the main factors controlling the levels of contamination of fish in various pollutants remains the local context. Thus, regardless of the size of the organism and the nature of the pollutant considered, if it comes from a highly contaminated environment, it will be more likely to present itself with high levels of contamination. In a comparative study of contamination levels in various pollutants among several species of marine fish from the three major coasts of France, it has thus been shown that the small sharks (Scyliorhinus canuicula) presented contamination levels in arsenic and mercury three to five times higher in the Eastern English Channel than in the Bay of Biscay. On the contrary, the hake (Merluccius merluccius) was eight times more contaminated with mercury in the Gulf of Lions, in the Mediterranean, than in the Bay of Biscay. Likewise, the fishing of sardines in the Seine Bay was suspended for nearly twelve years due to their levels of industrial organic pollutants (or PCB) and is only reopened since 2022, for the months of April to June. Beyond the choice between small and large fish, the geographical origin therefore plays a fundamental role in terms of potential health risk. Finally, beyond the nutritional benefits and the potential risks associated with the presence of various contaminants in fish, a last point to consider concerns the effects associated with their capture or production. The global demand for salmon has led to the multiplication of intensive aquaculture farms, whose impacts on the environment are documented: eutrophication near the installations, dissemination of pathogens to wild populations, escape of individuals that hybridize with wild populations. In addition, the feeding of these farmed salmon is essentially based on animal meal produced from small pelagic fish, whose industrial fishing is in competition with the artisanal subsistence fishing in many countries that rely on it to ensure their food security. Finally, the fish densities in these aquaculture installations, which can reach several tens of kilograms per cubic meter, also raise fundamental questions in terms of animal welfare. The tuna fisheries in tropical areas, which are the source of the majority of canned products found in supermarkets, also have important environmental consequences, notably in relation to the bycatch they generate. In the Eastern Pacific, it is estimated that between 1993 and 2009, on average more than 45,000 sharks, 3,600 manta rays and several dozens of marine turtles are caught each year. Although tuna fisheries are not the only responsible, they play an undeniable role in the decline of more than 70% of shark populations worldwide from 1970 to 2018. On the contrary, due to their shorter lifespan, early maturity and high reproduction rates, small pelagic fish are relatively less sensitive to fishing pressure. Although many populations are nonetheless overexploited worldwide, reaching exploitation levels consistent with natural stock renewal represents a more realistic objective.