Global literature review - Qualitative section condensed

Qualitative findings

Having outlined the shape of the dried fish literature, we now turn to the value of dried fish as it has been represented within this literature. We ask: how and why have scholars from diverse disciplines written about dried fish? And what do their contributions reveal about how dried fish is a compelling area for continued research?

Unsurprisingly, we encounter significant differences how the value of dried fish has been represented. Perspectives range from a purely instrumental approach -- where dried fish is discussed as a means to improve health or material outcomes -- to a more intrinsic framing of value, foregrounding the sensorial and aesthetic qualities of dried fish. While these distinctions broadly reflect the methodological and epistemological contrasts between the natural sciences and humanities, we find that motivations for studying dried fish are often entangled in broader narratives or critiques. Below, we describe how the value of dried fish emerges in relation to three major framings. First, dried fish can contribute significantly to food and nutrition security, although contaminant and spoilage risks need to be addressed. Second, dried fish value chains provide economic opportunities to producers, processors, and wholesalers, but social inequalities can undermine full participation by all actors. Third, dried fish has a distinct importance as cultural heritage, reflecting both the historical role of dried fish in shaping settlement and trade, and the contemporary indentification of dried fish with culture, place, and taste.

(1) Dried fish can contribute to food and nutrition security

A range of development initiatives have made the case that dried fish is essential to reducing malnutrition among the world's poor. Consumption surveys indicate that traditionally-dried fish already provides a significant proportion of animal protein intake in the Global South, particularly among urban consumers [1]. Small fish - which are typically processed and consumed whole - additionally provide a majority of calcium intake among the poorest, serving in particular as the "milk of Southeast Asia" [2]. Applied research in this area has been driven by the goal of improving the accessibility or nutritional density of dried fish product. The FAO has promoted sun-dried fish production to tackle food insecurity in Somalia [3], for instance, while nutrition scientists funded by DANIDA have engineered nutrition-dense food supplements that include dried fish, designed for the extremely poor in Cambodia [4] and Kenya [5]. Dried fish powder intended to meet the nutritional needs of the extremely poor has been developed using byproducts from fish processing factories in Ghana [6]. Kent [7] provides a prescient early policy oriented overview of the role of fish production and consumption (including dried products) in alleviating malnutrition throughout the Global South, and provides policy recommendations for maximizing their potential to contribute to this goal.

As indicated by the quantitative analysis above, technical studies dominate the literature on dried and fermented fish. Much of this technical research bears directly on the nutritional value and risks associated with dried fish products. Nutrient content analysis has demonstrated the nutritional value of dried and fermented fish products, typically by profiling the micronutrients, protein, fatty acids, fibre, ash, and moisture content of products available in local markets [8]. Some studies have tested the effects on nutritional profiles of temperature and other environmental storage conditions [9], methods of fish handling and evisceration [10], degree of fermentation [11], salt concentration [12], or smoking and drying techniques [13], suggesting the possibility of enhancing nutritional quality through processing improvements.

Several research groups have isolated and characterized lactic acid bacteria strains in fermented fish products, supporting the goal of improving production technologies or developing mixed starter cultures for industrial processing of products with optimal sensorial, probiotic, and microbial safety characteristics. Such research has examined products as varied as hentak, a fermented sun-dried powdered fish from India [14]; adjuevan, a condiment produced from spontaneously-fermented fish in Cote d'Ivoire [15]; suan yu, a Chinese fish snack made by mixing fermented then dried fish pieces with spices and corn meal [16]; and ngachin, small fish fermented with boiled rice in Myanmar [17].

The nutritional value of dried fish may be offset by contamination or spoilage, which are known issues of concern in sites where dried fish is widely traded and consumed. Microbiological studies of dried and fermented fish products have identified unsafe bacteria or fungi in commercially available products from local markets, occasionally measured in relation to variables such as storage temperature [18], the use of improved technologies such as solar dryers [19], ingredients and processing conditions [20], or starter cultures used in fermentation [21]. The survival of zoonotic parasites in fermented fish products is also a potential concern [22], albeit one that has not received much research attention.

Food quality analyses have identified multiple forms of contamination in traditionally produced dried fish. In addition to physical contaminants such as sand [23], dried fish have been found to be contaminated with heavy metals such as lead and mercury [24] or microplastics [25]. A more significant and widespread source of contamination involves hazardous pesticides applied directly to fish by processers and traders to prevent losses due to blowfly and beetle infestation. Although the application of controlled or banned toxins such as DDT and dichlorvos in fish drying or storage has been a recognized problem since the 1980s [26], safe alternatives have yet to be adopted on a wide scale. Hazardous pesticide levels continue to be detected in dried and smoked fish samples from Nigeria [27], India [28], and Bangladesh [29]. Finally, several studies have measured known genotoxins, notably the carcinogenic polycyclic aromatic hydrocarbons (PAH) that commonly occur in smoked foods, with recent analyses of product samples from Sub-Saharan Africa, Eastern Europe, and Asia finding PAH levels far in excess of limits set in food safety standards [30]. Concern for the creation or better enforcement of food safety standards is an underlying theme in much of this research.

Overall, research on food safety and nutritional aspects of dried and fermented fish addresses several long-standing challenges. As early as the 1970s field experiments were being conducted with the use of improved fish-drying methods such as elevated racks [31] or the application of less hazardous pesticides (such as pyrethrins) to control blowfly and beetle infestations during sun-drying of fish [32]. Examples of such initiatives include fish smoked in kilns rather than on bamboo racks in India [33]; dried fish produced locally in Nigeria using a solar tent dryer, to replace low-quality imported dried fish [34]; or a fish sauce produced in India using a new starter culture that reduces fermentation time and improves nutritional quality [35]. The poor adoption of safe and effective processing technologies indicates a need for greater attention to the socio-economic factors that may limit their uptake.

(2) Dried fish value chains provide economic opportunities to producers, processors, and wholesalers

The next largest subgroup of literature after primarily technical studies concerned with the material characteristics of dried fish as a food product, consists of assessments of value chains and markets. Such studies are often outputs of projects funded by overseas development assistance, and have an exploratory and diagnostic orientation, geared toward understanding the current "status" and the identifying technical or institutional challenges that could be addressed through interventions. Useful multi-country studies of production, marketing and consumption include Moen [36], covering Africa, Asia, Latin America and the Caribbean, and Europe; Reynolds [37] on Eastern and Southern Africa; and Essuman [38] on African fermented fish products. On a smaller geographical scale, Kabahenda and Husken [39], Kouakou et al. [40], and Ou [41] provide interesting reviews of the market for low-value fish products around lake Victoria, the production and marketing of fermented fish in Cote d'Ivoire, and the trade in fish products on the Tonle Sap in Cambodia, respectively. Kassam et al. [42] and Salagrama [43] offer a good examples of development-oriented value chain studies from Sierra Leone and Odisha, respectively. Upadhyay et al. [44] is a particularly thorough analysis of dried fish value chains in Northeast India, including a quantitative survey of marketing margins and credit utilization. Sinh et al. [45] offer a detailed descriptive and financial analysis of the snakehead value chain in Vietnam and Cambodia. Hossain et al. [46] provide a comprehensive qualitative scoping study of dried fish value chains in Bangladesh.

Another set of studies applies what might be termed a 'business management' lens to dried fish value chains, mostly focused on the salt cod trade between northern and southern Europe. These studies tend to have both strong conceptual framings and an applied focus on solving problems encountered by businesses. For example, Donnelly and Karlsen [47] address the question of how to institute traceability system in salt cod supply chain; Hameri and Palsson [48] examine methods for instituting efficient supply chain management in the export oriented Icelandic fishing industry in the face of fluctuating product volumes; and Korneliussen et al. [49] evaluate objective and subjective dimensions of quality assessment deployed by businesses in the stockfish industry. Other studies in this category focus on applied consumer research linked to marketing initiatives [50].

A small number of studies evaluate the extent of waste and loss in dried fish value chains in Africa and South Asia. Sharma et al. [51] is a very detailed assessment of post-harvest losses in the fisheries sector in Gujarat, India. Kefi et al. [52] use fish loss assessment tools to evaluate physical losses of fish along the value chain from the Barotse floodplain Zambia. Eyo [53] examines the incidence of loss and waste linked to handling practices at different segments of the fisheries value chain in Nigeria. King [54] offers an unusual assessment of artisanal containers used for transportation of smoke-dried fish in Nigeria, in relation to waste and loss. Salagrama [55] is an important evaluation of changing bycatch utilisation in Indian fisheries, linking bycatch use to technological change and evaluating the food security implications.

A varied set of publications, originating mainly from the fields of anthropology and geography, addresses the social dynamics of markets with a predominant focus on the Global South. Abbott et al. [56] address fish vendors' livelihoods and the political ecology of fish marketing and in Namibia. Imai [57] describe the social organization of fishing and fish marketing in Bangweulu Swamps in Zambia, and how these have evolved in the context of economic and ecological change, and the influence of a large conservation project. Medard and Dijk [58] and Medard et al. [59] examine the impacts of globalization on the fisheries of Lake Victoria and analyze social relations and market power in the value chain for kayabo, a small dried fish harvested from the Lake Victoria. Hayward and Mosse [60] provide and unusual study of the dynamic and rapidly changing 'foodways' involved in the smoked tuna trade in Ambon, Indonesia, and the socio-political and cultural forces that influence them. Also in Indonesia, Acciaioli [61] provides a detailed anthropological account of the role of migration and social capital in dried fish marketing at Lake Lindu, Sulawesi. Floysand and Jakobsen [62] also evaluate the role of social capital in their detailed economic geography of the formation of Norwegian fish-processing clusters. A more descriptive subset of studies focusses on the behaviour of marketing intermediaries, including urban dried fish traders in Mumbai, India [63]; women involved in fish marketing, in coastal Andhra Pradesh [64] and the Philippines [65], and smoked fish "middlemen" in Borno State, Nigeria [66]. Salagrama [67] provides a detailed assessment of livelihoods in different nodes of the fisheries value chain in Odisha, India.

Social inequalities can limit actors' ability to benefit fully from their participation in dried fish value chains. Several publications document exploitative working conditions associated with dried fish production, including bonded labour and slavery, in Bangladesh's fish drying industry [68]. Pramanik [69] provides an investigation of the arduous working conditions faced by women employed in dried fish processing in the Indian Sundarbans. Due to the highly gendered nature of fish processing work, such inequalities are experienced predominantly by women: worldwide, the preparation of dried, smoked, and fermented fish is almost universally conducted by women, the economic value and status of whose labour is typically low [70]. Various authors point to social and economic structures that shape women's participation in fish processing and marketing; looking at the Lake Victoria fishery, for example, Medard et al. observe that women processors' status has declined as a result of market consolidations and restructurings, which led to the exclusion of women who previously held positions of power in small-scale production and trade networks [71]. Cole et al., applying a social-ecological systems approach to the Barotse Floodplain fishery in Zambia, argue that gender inequality contributes to a maladaptive path dependency they describe as a “social-ecological trap” [72]. Other studies of women's labour in fisheries identify technical or material barriers to economic inclusion or productivity. Syampaku and Mifimisebi, contrasting the gender balance at each node in Zambian fish value chains, suggest that women lack access to higher-profit segments due to their poor access to capital [73]. Osarenren and Ojor argue that Nigerian fish processors are constrained by a lack of capital, cost of storage, and price fluctuation [74]. Simasiku et al. describe Namibian processors as confronting challenges related to cold storage facilities, poor weather, and packaging [75].

Several valuable studies focused on gendered work in fisheries originate from South Asia. Hapke [76] is a classic study of gender and household survival in fishing communities in a Kerala. Other examples include: Swathi and Dineshbabu [77] on women's roles in India's dried fish trade; Rajan and Biju's [78] study of the life and labour of fish-vending women in Kerala; Rabbanee et al.'s [79] livelihoods-oriented survey of women's involvement in the dried fish value chain; Hassan and Sathiadhas' [80] study of women's labor in fisheries sector in Kerala; Salagrama [81] on the masculinization of work in Eastern India's marine fisheries in a context of resource degradation; and Kusakabe's [82] examination of social relations, gender, and collective action in fish marketing in Cambodia. One notable contribution to gender ideologies in dried fish value chains is Aswathy and Kalpana's study of gender in a Muslim fishing village in Kerala, which describes how women engaged in fish drying and vending tactically negotiate the competing ideological expectations of feminine domesticity and women's entrepreneurship, set against a context of rapid socio-economic change [83].

Dried fish is important as cultural heritage

Research from history and other humanities disciplines draws attention to the historical and cultural importance of dried fish. Archaeological studies have demonstrated the existence of salt-making sites for fermented fish production in Asia during the Iron Age [84] and widespread salted fish processing in European antiquity [85]. Van Neer and colleagues have reported on fish bone assemblages indicating the presence of sun-dried, salted, and pickled fish at Roman sites located in Egypt [86]. Global trade in salt cod had a particularly important role in shaping colonial ties between Europe and the New World [87] and geopolitical relations in Atlantic Europe and Iceland [88]. Some research has addressed the role of dried fish trade in European settlement, investigating topics such as how proximity to fish and salt resources shaped settlement patterns in Ancient Greece [89]; how fish trade contributed to Greek colonization of the Black Sea region [90]; how dried fish production in the Viking Age laid the foundations for a global trade [91]; or how peripheral regions, such as Lusitania, came to be integrated into the Roman Empire through fish trade [92]. In the more recent colonial context, Reeves et al. describe how official Fish-Curing Yards came to be established in parts of India in the 1870s, as a mechanism to exempt fish processors from the colonial Salt Tax [93], resulting in the emergence of bonded arrangements between consolidated fish curer/traders and their suppliers.

Dried and fermented fish production can be understood as part of cultural adaptive strategies in response to specific environments. For example, Kenneth Ruddle describes the complementary development of fermented fish and rice in South-East Asia as a feature of highly seasonal floodplain river environments, suited to alternating production of fish and rice [94]. Similarly, Vietnamese fermentation practices reflect a combination of distinct ecological features and biological rhythms, making use of small fish that can be fermented uniformly, that are of low economic value (and thus protected from competing uses), and that can be harvested. Ruddle and Ishige's important cultural ecology of fermented fish convincingly proposes a direct link between environmental conditions and the choice of fish preservation technologies in South-East Asia [95]. From a cultural ecology perspective, fish drying may be taken as an adaptive requirement in environments that provide uneven access to fresh fish, either due to the seasonal availability of fish or to the need to exploit fish in combination with inland resources. In this sense, cultural preference for dried fish can often be traced historically to specific environmental conditions in which fish preservation originally offered a means of avoiding food shortage [96].

Dried fish may be approached as a subject within world food history, recognizing the role of dried fish as culturally important commodities within global trade systems. A particularly significant historical dried fish product is the fermented fish sauce garum, a central element of ancient Greco-Roman cuisine, which was celebrated for its flavour and supposed medicinal value in addition to serving as a major trade commodity [97]. In some settings, garum finds itself at the intersection of food history and gastronomy: taking an experiential approach to food history, a medieval Roman banquet reconstructed at the Ashmolean Museum in 2017, for example, featured a menu consisting largely of salt fish and garum-flavoured dishes [98], while a team of Danish food scientists has recently developed a series of modern, experimental garums [99].

Other dried and fermented fish products are situated within cultural movements that are produced by, but also oppose, global flows. Thus the Portuguese national dish bacalhau (salt cod) would be unthinkable without colonial connections to Newfoundland, which allowed cod - among other ingredients linked to conquest - to enter the Portuguese diet in the 16th century [100]. Historical studies on Newfoundland and Labrador fishing communities [101], meanwhile, provide a clear indication of how global trade relations ultimately shaped both the establishment of isolated coastal communities and the emergence of a unique culture within them. In Japan, katsuobushi (smoke-dried shipjack tuna), whose name auspiciously means “victory-bringing fish”, is entangled with commercial, military, and Imperial history - its early spread being attributed, for example, to 11th-century Imperial policies that prohibited the consumption of meat to promote Buddhism [102]. Fermented fish has more recently become an important marker of localness and tradition in the Faroe Islands, drawing on associations with the Slow Food movement [103]. Research exploring cultural heritage value has tended to focus primarily on European fish - such as surstromming (Swedish fermented herring), whose consumption helps construct a traditional rural identity in opposition to modern, urban values [104]; and bacalhau (Portuguese salt cod), which is embedded in collective identity narratives and may be seen as a form of cultural capital [105]. A related approach takes dried fish as part of foodways, systems of culturally-significant practices through which identity is negotiated through local foods, such as fermented fish in Thailand [106] or smoked tuna in Indonesia [107].

Taste for fish may be considered as a cultural attribute. The idea of culturally informed “acceptability” figures prominently in research on product development and consumer preference, as reflected in studies exploring topics such as the contrast in acceptability criteria for spice-cured sprats in Estonia and Thailand [108], regionally distinct tastes for salted cod in different parts of Spain [109], local quality appreciation criteria for lanhouin (fish-based condiment) in Benin [110], or fermentation leading to improved acceptability of poor-tasting fish in Nigeria [111].