Global literature review - Discussion

Our literature review was guided at the outset by the goal of following dried fish across value chains, exploring how fish are embedded in social and economic relations that extend from processors to consumers. This approach has allowed us to map out existing literature that describes the value transformations in each segment of the value chain. At the same time, our exploration of this literature has encouraged us to problematize the logic of a "value chain" as representing a linear accumulation of economically legible value; instead, we observe distinct forms of value that may be created and experienced by specific actors in particular contexts. As such, our literature review prompts a broader interrogation of how the value of dried fish is perceived: how is dried fish valued as a commodity, as a support to food and nutrition security, or as a marker of taste and social identity? To what extent are these forms of value represented in the published academic literature concerning dried fish, and what types of value are overlooked? And finally, what is the potential for transdisciplinary research to bring these diverse forms of value into clearer focus?

Mapping value chains

Mapping the literature on dried fish by value chain segment, we observe that production and processing segments dominate the literature. Food science research, unsurprisingly, focuses almost entirely on the processing stage, with some studies identifying impacts on food consumers (e.g., food safety and nutrition) or connections with fresh fish suppliers. While a greater balance of coverage is evident in the literature on the themes "value chains, economy, and labour", "culture and social relations", and "policy and governance", trade and retail segments remain underrepresented. We were unable to locate sources that explicitly address all five of the value chain segments, and the number of publications that described interactions across three or four value chain segments was negligible.

Although 70% of the fish processing-related publications we reviewed did not address any of the non-processor value chain segments, we found that between half and three quarters of the publications that addressed other segments also mentioned processors. The reference to processing in literature on other value chain segments is not entirely unexpected, given that dried fish is, by definition, a product shaped by specific processing actions. Over 90% the publications that only addressed the processing segment belonged to the category we labelled as "technical" research, which encompassed food science and engineering studies. These publications either examined dried fish as a physical product separate from its social context, or described the impacts of processing technologies on the product, with minimal reference to the social or economic contexts of production, trade, and consumption.

Thematic coverage in the DFM Zotero library by value chain segment. Each shaded bar segment represents a number of references pertaining to a value chain segment for a given theme. Numbers presented within each bar represent the total number of references; the length of each bar segment represents the volume of references concerning the respective value chain segment in relation to the others. References may be counted in more than one segment. 32% of the items in our sample were not identified as having a clear value chain segment and were therefore excluded from this analysis.

Themes and clusters

Our choice to organize the research around the concept of value chains was guided by an awareness of limitations in our own research on food security and well-being, which has largely emphasized the experience of fishing communities. A fisheries lens does not adequately capture the importance of dried fish in the lives of downstream actors; nor does it capture the complex relations among value chain actors, which could potentially dictate how fish are caught, processed, sold, and eaten. As we noted at the beginning of this review, the broader literature on fisheries often emphasizes ecology and governance – issues of vital importance to fishing communities – but generally ignores food safety, nutrition, food security, and health, all of which are dominant topics within the literature on dried fish. Our approach in this literature review, therefore, has been guided by the goal of initiating a transdisciplinary discussion of dried fish among researchers and practitioners whose work addresses fisheries governance, food science, and the humanities.

At the outset of our analysis, we developed a list of thirteen themes reflecting topics of known interest, building on the findings from a preliminary literature review completed for the Dried Fish Matters project proposal. We deliberately framed our classification by substantive topic rather than by disciplinary or methodological approach, so as to allow us to locate evidence of transdisciplinary research contributions on each of the topics. Where several of these themes had the potential to be dominated by specific disciplines (e.g., history for the theme "history/change", macroeconomics for the theme "economy"), we sought out diverse evidence related to those themes. Thus under the theme "macroeconomics" we include historical research describing the regional importance of the salt fish economy in the Black Sea region in antiquity [1], business economics research on the impacts of shifting markets for salted fish in Spain on Norwegian industrial producers [2], and a technical study arguing for standardization of fermented fish processing practices in Africa, in order to reduce food safety concerns and increase marketability [3]. Interestingly, nearly half the references we tagged under this macroeconomic theme pertained to regional dried fish economies in historical perspective – primarily covering European and transatlantic trade, but also including more obscure trade networks such as the supply of dried fish from the Kingdom of Huarco with the Inca in ancient Peru [4], or the colonial-era trade in fish produced by Chinese fish curers in Victoria, Australia [5]. In this sense, our thematic classification of the literature reveals the potential for describing dried fish economies in ways that combine disciplinary perspectives, such as using historical research to provide insights into contemporary cultural practices and trade patterns. Nonetheless, we were disappointed not to find many examples of deliberately transdisciplinary approaches within this body of literature.

We observed a clear divide between humanities and natural science research, which was unsurprising yet somewhat more pronounced than we might have expected. It became apparent at an early stage of our review that over two-thirds of the resources we had collected were of a technical nature, consisting mainly of publications that document the chemical and microbiological composition of dried fish samples. We settled on the term "food science" to describe these publications, highlighting their shared attention to dried fish as a food that can be understood through scientific analysis. We observe that publications in this area present few intersections with other themes and disciplines. A significant exception is the use of nutrient analysis in research on food and nutrition security interventions, which typically address socio-cultural factors such as acceptability, uptake, and policy measures [6]. It is worth noting, however, that this more transdisciplinary literature is very small; we identified only 14 of over 1100 items in our database as directly concerning food and nutrition security in relation to dried or fermented fish.

For analytic purposes, we grouped several of our thematic tags into three broader categories, based on our observation of clusters of interest within the literature: (1) "food security, health, and nutrition" (24% of the total sample); (2) "value chains, economy, and labour" (21% of the total sample); and (3) "culture and social relations" (11% of the total sample). Each of these thematic clusters represents a distinct way of conceptualizing the value of dried fish. In the first instance, dried fish is valued as meeting the biological needs of humans, which it does by providing safe nourishment, potentially at times of food scarcity. In the second instance, dried fish is valued as a commodity that sustains the livelihoods of fishers, processors, traders, and retailers. In the third instance, dried fish is valued as a cultural object, whose production and consumption is tied to shared practices and identities. Having identified trends within each of these value clusters, we explored the research possibilities suggested by the intersections between them, as represented in the accompanying figure. To simplify the analysis we excluded food science literature from this representation, given its lack of overlap with other themes, but incorporate research questions from food science under "food and nutrition security and health". The policy and governance theme, which dominates the general fisheries literature, is also excluded as a distinct theme but may be considered to apply to the entire analysis, as suggested by our discussion below.

Thematic clusters

Thematic cluster	Subthemes
culture and social relations	culture, social relations, and well-being food and cooking gender history / change political ecology
food and nutrition security and health	food and nutrition security health
value chains, economy, and labour	economy labour value chain / microeconomics

Food and nutrition security and health

The large body of food science research we collected in our review confirms that dried fish offers exceptional nutritional value. We know, as some authors have argued, that dried fish provides critical micronutrients to the world's poor and can contribute to malnutrition alleviation [7]. Nonetheless, published data concerning nutritional properties of dried fish are dispersed across the literature and have yet to be correlated with studies of consumption practices and dietary needs. Food science research also helps us to understand the forms of spoilage or contamination that are present in dried fish products. We know, from this research, that spoilage and insect infestation are widespread problems encountered by processors, but also that great harm can be done by the measures taken to counteract these problems – notably the application of harmful chemical pesticides and preservatives. Food scientists have explored the effectiveness of treatments such as irradiation [8], salting [9], or safer insecticides [10]; yet the poor uptake of such technologies suggests the need for better research into economic decision-making among dried fish processors, wholesalers, and retailers.

A small body of research on food and nutrition security builds on these findings to tell us how dried fish products, including food supplements, can be enhanced or disseminated to meet the nutritional needs of the world's poor [11]. While component analyses highlighting the nutritional value of various processed fish products are available, we lack systematic research investigating the connection of dried fish consumption to positive health outcomes. We also lack research addressing how changes to nutritional value and nutrient concentration, brought about by dehydration or fermentation processes, impact actual dietary nutrient intake when fish is consumed dried instead of fresh – or as an alternative to other protein sources.

Research into the health risks of dried fish consumption, particularly the potential negative impacts of elevated smoked or salted fish intake, has been somewhat inconclusive. Multiple dietary studies from the 1980s and 1990s identified salted fish consumption as a risk factor contributing to the relatively high incidence of nasopharyngeal carcinoma among Cantonese, Malaysian, and other South-East Asian groups [12], though this correlation has more recently been challenged [13]. Other research has suggested a connection between salted fish intake and hypertension [14] and brain cancer risk [15], while fermented fish sauce has been linked to esophageal cancer [16]. This remains an area of importance for continuing research.

Value chains, economy, and labour

Research on the economy of dried fish processing and trade tells us that dried fish value chains are essential to the livelihoods of people around the world. Studies in this area, particularly those that combine descriptive and quantitative data, help us to understand how dried fish value chains operate and how they are financed [17]. Business-oriented studies tell us how transnational businesses can optimize supply chains, particularly for salted fish [18]. At the more local scale, qualitative studies tell us about the impacts of changing markets on value chain actors' livelihoods, or how social inequalities affect participants in small-scale value chains [19].

We find that much of the research on dried fish value chains and labour is descriptive rather than critical – enumerating fish products and species, summarizing the stages of fish processing technologies, or outlining distribution channels, without commenting on the political economy of value chains and labour relations. If adequate attention is given to social inclusion and rights issues, however, this thematic area offers strong potential for policy, goverance, and development guidance. Some current research on dried fish value chains highlights issues of labour exploitation, for example among child and migrant labourers in Bangladesh [20], as well as challenges faced by women vendors and processors in places such as Cambodia or Kerala, India [21]. These topics merit broader attention in other sites and value chains. We additionally note that research in this area has not systematically addressed how value chain actors are affected by regulatory regimes, such as the imposition of food safety standards or labelling requirements applied to fish packaged for sale in supermarkets or for export.

Culture and social relations

Historical and archaeological research informs us that dried fish processing and trade activities have shaped settlement, migration, colonialism, and international trade. European colonialism in North America was largely driven by trade in salt cod [22], while settlement patterns in Europe and elsewhere have mirrored sites favourable to fish preservation [23]. Cultural ecological studies suggest that fish processing has historically grounded specific products and cultural practices in particular locations, with enduring presence in contemporary cultures [24]. We also know that fish products operate as symbolic markers of culture and identity, with taste preferences for dried fish marked by cultural upbringing and social relations [25].

We include the social relations of fish processing and trade within this thematic cluster, noting the particular importance of gender issues in the dried fish sector. We know that women rarely participate in offshore catch directly, though they will mend nets or may harvest low-value, inland species or shellfish, or in some instances can be financial managers and boat owners; women are almost always involved in fish processing, though men may participate also; and in some countries women may run wholesale or retail businesses, sometimes independently of a processing operation [26]. As Belton and colleagues have pointed out, however, much of the literature on fisheries focuses on fishers rather than onshore processors, such that women's labour tends to be hidden [27]. With some exceptions [28], we find that publications on women's role in dried fish value chains have failed to engage the critical perspectives on gender taken in social science and feminist theory.

Thematic intersections

In keeping with our aspiration to promote transdisciplinary research, we examined the potential for research at the intersections of the three thematic clusters. We emphasize that the number of existing publications addressing each of these thematic combinations is very small; our exploration therefore highlights a number of unrealized research topics that are suggested by current research.

This Venn diagram illustrates the intersection of major themes in the dried fish literature, based on a review of resources collected in the DFM Zotero library. Themes in the literature were grouped according to three main categories, which reflect the tag combinations: (1) ##THEME: food security, health, and nutrition; (2) ##THEME: value chains, economy, and labour; and (3) ##THEME: culture and social relations.

At the intersection of food and nutrition security and health and value chains, economy, and labour (3% of the total sample), we recognize the potential for research that further examines actual consumption patterns and assesses the importance of dried fish to material well-being and health. We already see a rich body of food science research addressing the question of how losses due to spoilage and contamination can be reduced, offering the possibility of decreasing both economic loss and loss of nutritional value. A related body of research, with more of an engineering focus, takes a converse approach by proposing new processing techniques and products that add nutritional and economic value.

At the intersection of food and nutrition security and health and culture and social relations (6% of the total sample), we observe the potential for research assessing how customary fish processing practices actively contribute to food and nutrition security, notably by providing an inexpensive and accessible "reserve" food source. In a similar vein, we have noted studies addressing the local acceptability criteria for food supplements that incorporate dried fish powder. Further research in this area can support dried fish production and consumption as a culturally appropriate food that can meet the nutritional needs of consumers.

At the intersection of culture and social relations and value chains, economy, and labour (17% of the total sample), we observe a significant number of studies that address how cultural food preferences influence economic value, or how traditional processing technologies shape contemporary value chains. We also note the potential for studies of how diaspora communities are implicated in the emergence of new trade networks and value chains, as well as new consumption practices that foreground the role of dried fish as cultural heritage. Research in this domain can also inform us of the ways that historical patterns of economic development have shaped long-term cultural preferences for dried fish.

The number of resources in our sample that address themes from all three clusters is negligible. Notable publications that take a holistic view of dried fish economies include Kurlansky's Cod: A Biography Of The Fish That Changed The World [29], which explores the 600-year world history of cod fishing and salt cod trade with reference to culture and geopolitics; Mak Sithirith's political-economic study of fishing villages surrounding the Tonle Sap Lake in Cambodia [30]; and a BBS/ILO report on children's labour in the fish drying industry in Bangladesh, which addresses themes of well-being, economy, gender, health, microeconomics, and labour relations [31]. All three of these studies are notable for their attention to the human dimensions of dried fish economies, identifying the impacts of economic practices at scales ranging from the individual to the regional or global political economy. While we do not propose that such studies should serve as a universal model for research on dried fish, we underline the need for additional integrative, transdisciplinary research that focuses on the human aspects of dried fish value chains.

Conclusion

We opened this literature review with a comment on the distinction between the literatures on "fisheries" and "dried fish". While we have not attempted to engage this contrast systematically, our review demonstrates that natural and social scientists whose work concerns fish or fisheries can gain valuable transdisciplinary insights by looking at downstream value chains. We have seen evidence that dried fish makes an important contribution to the livelihoods, health, food and nutrition security, and social and cultural well-being of people around the world. We emphasize the importance of research that promotes the role of dried fish in providing security to the most vulnerable groups, and that recognizes its combination of nutritional, economic, and cultural value.

Despite the clear importance of dried fish in people's lives, we observe that research on dried fish processing, trade, and consumption practices remains limited. A significant majority of research on dried fish and fish processing is undertaken from a food science or engineering perspective, with limited attention to the social and cultural dimensions of dried fish value chains. By engaging in further transdisciplinary research that addresses dried fish in its social context, it will be possible to support policy, governance, and development initiatives that better acknowledge and promote the diverse forms of value in dried fish value chains.