Environmental Attributes of Wild versus Farmed Tuna: Beliefs, Knowledge and Purchasing Choices of Italian Consumers of Canned Tuna

: The study investigates the perception of the environmental sustainability of wild-caught versus farm-raised tuna production among a sample of Italian consumers. Awareness, concern, knowledge and beliefs related to the environmental impacts of wild and farmed tuna, and the attention given to environmental attributes when purchasing canned tuna, are tested for signiﬁcance based on the socio-demographic characteristics of individuals. The results show that respondents are aware and concerned about the environmental challenges in ﬁsh production, but more than half of the sample has no or little knowledge of the environmental sustainability of both wild and farmed sources of tuna production. They indicate impacts in terms of by-catch, marine ecosystems and species reproduction for the wild source; for the farmed source, environmental issues related to the feeding and risk of the virus are reported. Most respondents believe that the wild ﬁsh source has a greater environmental impact than the farmed tuna production. Plastic contamination, separate waste collection and air emissions are other environmental challenges respondents mostly consider. Finally, minimal attention is paid to environmental attributes when purchasing canned tuna, and the production method of the ﬁsh is ignored.


Introduction
Environmental sustainability in seafood production and consumption is an important global issue that asks for adequate measures in order to face the increasing seafood demand [1] in the face of scarcity in fish supply and stock over-harvesting.In fact, due to the increase in capture fishery production and unsustainable fishing practices, some wild stocks are at risk of depletion which affects marine biodiversity [2].As an alternative to wild-caught fishing, fish farming has become an important source of food, but even for this source some concerns about potential environmental impacts have also increased [3,4].
For the above reasons, it is extremely important to assist consumers in their decisionmaking and purchasing choices towards products obtained from environmentally sustainable fisheries and aquaculture [5,6].For this to occur, it is important to fully comprehend what consumers know about the environmental sustainability of fishery and aquaculture production and which aspects are relevant to their opinions and purchasing choices [7].
Recent literature has assessed the consumer's preference for environmentally sustainable seafood products [8][9][10][11][12] and the importance assigned to environmental attributes in making consumption choices [13][14][15][16].These studies revealed the sensitivity of the results depending on whether it concerned the sustainability of seafood in general or some specific products, and whether the analyses focused on environmental attributes or considered other product characteristics.Regarding farmed products, people's attitudes toward aquaculture are related to the perceived environmental impact, as reported in several studies at the national scale, such as those dealing with Canada [17], Norway [18], Spain [19] and Scotia [20].Fewer studies addressed the topic of consumers' attitudes, beliefs and preferences toward seafood sustainability by comparing wild-caught versus farm-raised fish [21][22][23].
Environmental knowledge and information have also been identified as factors that encourage consumers to choose sustainable seafood products [8,24,25], although their effects are controversial [26].Among the studies that addressed the role of environmental knowledge and concern in consumers' preferences, there are those referred to Belgium [27], Ireland and Norway [14,28], Portugal [29] and Italy [30].The study by Carlucci et al. [10] showed that not understanding the information accompanying products makes EU consumers less likely to consume fishery and aquaculture products.Other authors assessed that having information about aquaculture operations reduces the negative attitude toward farmed products [5,31].Among the key factors that conditioned the sustainable image and acceptance of the farmed fish, some authors considered the lack of information regarding aspects such as sustainable breeding techniques [28,32].Other environmental aspects studied in seafood choices were biodiversity loss and the overuse of antibiotics and pesticides [33]; in addition, appropriate feeding emerged as the most influential factor in choosing farmed fish [24].
Socio-demographic variables are considered in the literature on the topic as factors capable of explaining differences in individuals' beliefs, motivations and purchasing choices.In particular, among these variables, the most considered in the analyses are gender, age and the level of education of the respondents [8,10,11,25,29,34,35].
Compared to the abundance of studies dealing with the purchasing choices of environmentally sustainable fish products, fewer studies have focused their analyses on tuna and on European consumers.The study of Davidson et al. [36] investigated the tuna fish purchases of consumers in Hawaii and deepened the comparison of wild versus farmed, as well as the importance of environmental factors.A different perspective was followed by Pérez-Ramírez et al. [37] that found that Mexican consumers who preferred canned tuna had a lower frequency of consumption compared to those who preferred fresh fish; in addition, having information about ecolabels made them more eager to consume canned tuna.The study by Zhou et al. [38] found positive preferences and willingness to pay for eco-labeled tuna steak among consumers in Kentucky that were less likely to purchase wild-caught tuna species.Finally, the study of Lim et al. [39] compared imported canned tuna and domestic products among American, Ecuadorian, and Vietnamese consumers but did not consider the wild or farmed fish source; in addition, they found country-specific effects.Previous studies [30,40] on the sensitivity of Italians towards the environmental sustainability of canned tuna have not investigated the comparison between the wild-caught and farmed sources in relation to people's knowledge, beliefs and purchasing behavior.
The study aims to contribute to the above literature on sustainable seafood consumption and purchasing choices by adopting a focused approach that concerns both the product, i.e., the canned tuna fish, the sustainability pillar, i.e., the environmental pillar, and the country dealing with a sample of Italian consumers.
Concerning the product, canned tuna is an interesting product to study for two main reasons.One reason relates to being canned tuna one of the most traded products in the global supply chains [1,41] whose global demand will continue to increase [42].As currently the fattening and farming of tuna are mainly destined for the fresh market, and the canned tuna industry continues to depend on capture-based fisheries for its raw material in order to satisfy the growing demand [43].Future scenarios are quite complex and although farmed production is expected to increase, it is not clear if it will dampen or not the fishing pressure on wild stocks [44].
The previous consideration lead to the second reason for the study which pertains to the environmental sphere and to some related issues: firstly, despite the efforts of the EU (Reg.2016/1627, Reg.2023/194) and of the regional organizations managing global tuna fisheries and tuna quota mechanism, the presence of world stocks that are overexploited or at risk of overfishing such as the Southern Bluefin Tuna, the Pacific Bluefin Tuna and the Bigeye Tuna, as reported by the IUCN Red List of Threatened Species; secondly, the environmental relevance of the global supply chain; and finally, the problem caused by illegal, unreported and unregulated fishing activities [45].
Finally, the choice of Italy is motivated by the fact that the country has a long tradition of tuna production that in recent years has suffered from competition [46], although it remains strategic according to the National Strategic Plan 2021-2027 [47].Furthermore, Italy is one of the main tuna importers in the EU in order to support with raw materials national canned tuna industry and is experiencing a decline in production against an increase in domestic consumption [1].Data from the European Market Observatory for Fisheries and Aquaculture Products report that among the main commercial species imported into Italy in 2021, skipjack tuna alone accounts for 7% of total imports in nominal value (https:// www.eumofa.eu/en/italy,accessed on 10 March 2022).As far as canned tuna is concerned, according to ANCIT, the National Association of Preserved Fish and Tuna Producers, in 2021 the national production exceeded 83,000 tons and consumption by 159,000 tons; in ten years the value of the canned tuna market has increased by 31.3%, the domestic production by 18% and per capita consumption by 17.4% (https://www.tonno360.it/,accessed on 17 March 2022).Regarding farmed fish production, the country is positioned among the top EU countries, although it remains highly dependent on imports, it suffers from firms' inefficiency and is concentrated on a few species, such as trout, clams, mussels and sea bream [48,49].
This study is part of a larger research about the Italian consumer's perspective on the environmental sustainability of canned tuna that has been carried out in recent months [30,40].Within this larger research, the aim of the present study is twofold: to analyze the knowledge and beliefs of consumers about the environmental sustainability of wild-caught versus farmed tuna production, and to investigate the attention given to environmental attributes in the purchase of canned tuna fish.To achieve these aims, consumers' opinions about the environmental characteristics of the two sources of tuna fish production were primarily investigated.People's opinions and beliefs were then analyzed in relation to some socio-demographic factors and to the frequency of consumption in order to assess whether these variables differentiate people's profiles.

Materials and Methods
A web-based survey was conducted with Italians aged over eighteen in April-July 2022; individuals included in the sample are consumers of canned tuna fish who are involved often/always in food purchases.Study participants were enrolled in two stages.In the first stage, individuals were identified within the researchers' networks using convenient sampling but paying attention to include different ages, gender, and educational background.Individuals were informed that their participation in the survey was voluntary and anonymous and were asked to fill in a questionnaire through the Google Forms Platform.In the second step, these individuals were invited to forward the link to friends, family and colleagues by following a snowball method [50].The non-random nature of respondents' selection may have limitations in terms of potential bias [51] but representativeness and inferences [52] were not within the study aims.
The questionnaire was tested in order to verify any uncertainties in understanding the questions; it was preceded by a short description of study aims and by the request for consent.
The questionnaire was organized into four sections (an extract of the questionnaire is reported in Appendix A).
The first section collected information about the respondents' knowledge, awareness and concern about the environmentally related topics of seafood production [53]; in addition, the perceived level of the global environmental impact of wild-caught versus farmed fish production was explored.Respondents' opinions were collected on the basis of a 5-point Likert scale ranging from "totally disagree" (1 point), "partially disagree" (2 points), "nor disagree or agree" (3 points), "partially agree" (4 points), to "totally agree" (5 points).
The second section deepened people's knowledge about aspects that may favor the environmental sustainability of tuna production when obtained from wild-caught sources or from farm-raised production, and under a general perspective; these aspects were selected based on Zander et al. [54] and other studies reported in the literature background.As above, respondents' level of agreement or disagreement with each statement was expressed based on a scale ranging from 1 point "totally disagree" to 5 points "totally agree".Aspects concerning wild-caught tuna that can make this more environmentally sustainable included the reduction of impacts on marine life, the respect of the biological reproductive cycle of tuna stocks, the reduction of discards of non-target and non-commercial fish products, the reduction of the risk of catching endangered, threatened and protected marine species, and other marine ecosystem damages, such as those on the deep-sea and the sea floor.Specific issues concerning the environmental sustainability of farmed tuna included practices reducing fish infections and diseases caused by parasites, bacteria or viruses; farming practices free of antibiotics; avoidance of capturing endangered, threatened and protected marine species; and finally, the avoidance of other damages on marine ecosystem as well as the deep-seawater and seabed.Finally, as regards general environmental issues that may regard both wild and farmed tuna production, they included energy efficiency, air emissions, separate waste disposal, and plastic and micro-plastic outflow in marine waters.Indeed, the impacts in terms of greenhouse gas emissions and energy were proven to be critical [55,56], mainly for species that are globally traded and involve post-harvest transformations, as in the case of tuna fish and canned products.For each source of tuna production, the list of environmentally sustainable aspects included at least a response item that is fake or controversial: for wild captured tuna, the use of Fish Aggregating Devices (FADs), banned in the EU legal framework, that are applied in some tuna fisheries worldwide [57]; for the sustainability of farmed tuna, the use of wild-caught fish meal or oil to feed farmed fish; finally, among the general practices of sustainability, the preference for big sized vessels instead of small artisanal fishery, and the capture/farming of fish in high seas as defined by to the UNCLOS Convention (art.86), instead of in marine areas within the national jurisdiction.Responses to the fake items were recorded in the statistical analyses.
The third section of the questionnaire dealt with the attributes individuals pay attention to when purchasing canned tuna fish; these attributes were selected based on some literature [10,38].Responses were measured on a 5-point scale in terms of the frequency of attention paid to product attributes when purchasing canned tuna (from never (1), rarely (2), sometimes (3), often (4), to always (5) paying attention).Some attributes mainly referred to the environmental intrinsic qualities of the fish, such as the fishing area, the fishing technique, the farming method, the presence of ecolabel, and the specie of tuna; in addition, the country of origin and the commercial brand of canned tuna were considered in order to catch the importance of attributes other than those expressing environmental sensitiveness [40].The price level was not considered: canned tuna market competition is not based on price levels that are highly accessible and makes canned tuna a standard low-price product in Western EU countries [58].As for the consumption frequency, canned tuna consumption was measured on a six-point scale in the form: "How often do you regularly consume canned tuna?": two-three times or more a week; once a week; once a month; less than once in a month; finally, seldom/never.
The final section collected respondents' characteristics, such as gender, age and education level attainment.
In order to deeply investigate people's opinions about sustainability aspects in the comparison of wild versus farmed sources and the purchasing behavior of individuals when buying canned tuna, a descriptive analysis was applied: first of all, the statistical distribution of the variables was provided and deepened according to some demographic characteristics of respondents.In order to check the internal consistency of each set of items and its reliability, the Cronbach Alpha test was conducted and alpha levels more than 0.7 were considered appropriate, but 0.8 and higher are preferred.Since the variables measuring beliefs about the environmental aspects were expressed in terms of ordinal scale, as measures of central tendency and variability we considered the median and the interquartile range, defined as the difference between the third and first quartile, it measures the width of the range of values that contains the "central" half of the sample; Kendall's tau-b correlation coefficient, with the Bonferroni adjustment to calculated significance levels, was applied to assess the strength and direction of the association between pairs of environmental aspects.Values of Tau-b range from −1 in case of perfect negative association to +1 in case of perfect positive association.
In addition, test analyses were applied to obtain a picture of differences in the distribution of phenomena by socio-economic variables, the level of knowledge about sustainability topics and the frequency of consumption of canned tuna fish.Non-parametric tests based on the Mann-Whitney test for two-sample statistics, and the Kruskal-Wallis test for more than two-sample statistics, were used.
The final sample was composed of 289 valid questionnaires.Descriptive statistics for demographics are shown in Table 1.

Concern, Knowledge and Beliefs about the Sustainability of Wild-Caught versus Farm-Raised Fish
Most respondents have heard about the issue of sustainability in fisheries before entering the survey (73%).However, 7% and 47% of the respondents consider their knowledge about the environmental sustainability of processes and products to be null or poor, respectively.The level of very poor/poor knowledge is higher among females (61.0%), respondents with postgraduate diplomas (60.5%), and aged 55 or over (57.8%).
A high level of concern about the potential environmental impact of fisheries was observed: 40% of respondents are highly concerned and 46% are quite concerned.Regarding the level of concern, the differences in responses by subgroups of personal characteristics are thin but report that males (44.7%) and the highly educated (48.7%) are more concerned than their counterparts.
Comparing beliefs about the impacts of wild fisheries and fish farming (Table 2), percentages reveal that people agree most on assigning impacts on marine ecosystems to the wild fishing activity than on fish farming indeed, around 80% of people assign impacts to wild-caught fish, while 50% agree on assigning impacts to farm-raised fish.Regarding farmed production, the distribution reports a high percentage of people partially or totally disagreeing (34%) and (17%) of people neither agreeing nor disagreeing.The median score corresponds to a high level of agreement with the statement about the environmental impacts of the wild source (4 = partially agree), while it corresponds to an intermediate assessment of respondents nor disagreeing or agreeing about the impacts of the farmed source (median equal to 3).The interquartile range indicates that the variability of the scores with reference to the beliefs about the environmental impacts of the wild source is lower than that for the farmed source.When asked to compare the two fish sources, the catching of the wild fish is considered to have a greater impact: around two-thirds of respondents totally or partially agree that the wild-caught fish is more impacting than the farmed fish.* Legend of scores (5-points Likert scale): totally disagree = 1; partially disagree = 2; nor disagree or agree = 3; partially agree = 4; totally agree = 5.
Females, postgraduates, and aged people showed a higher level of agreement (totally + partially) about the environmental impacts of wild-caught fish (Figure 1A).Regarding the impacts of farm-raised fish (Figure 1B), differences by gender in the level of the agreement are not so strong, while differences according to the education level attainment are marked and show that individuals with postgraduate education are more convinced of the impacts of farmed fish.Comparing both sources, postgraduate and aged people assign a greater impact on wild-caught than farmed fish production (Figure 1C).
In order to deepen the analysis of people's beliefs about the environmental issues related to tuna production, respondents were invited to agree to statements regarding the environmental sustainability of wild-caught tuna production, farm-raised tuna, and some general issues applied in both cases (Table 3).Regarding the internal consistency of items in each statement the results of the Cronbach Alpha suggest that the items have relatively high internal consistency: the consistency of the construct related to the environmental sustainability in wild-caught tuna was measured by a coefficient of 0.837; the reliability of the construct related to the sustainability in farm-raised productions was 0.865; finally, the Cronbach Alpha of the construct about general environmental issues was 0.797.
Regarding those issues that are relevant to wild-caught tuna, "totally agree" opinions point to the need of paying attention to the by-catch, of reducing impacts on the marine ecosystems and deep water, and of safeguarding the fish reproductive cycle.A lower attention has been paid to reducing fish discards, although the percentage of opinions partially or totally agreeing with the above impact is very high (71%).Considering the "fake" environmental issue of catching wild tuna, opinions about the use of fish aggregating devices are not so clear-cut and responses are distributed in quite similar percentages in all five classes, from totally disagreeing to totally agreeing.
Among the environmental issues specific to farm-raised tuna that should be addressed in order to be sustainable, the highest level of agreement (totally and partially) among respondents refers to the protection of the marine environment (the reduction of the bycatch of threatened species and impacts on marine deep water and ecosystem), and to aspects related to the proper management of farmed tuna breeding (i.e., avoid administering antibiotics and reducing pathogens and parasites risks for the animal welfare).Regarding the "fake" sustainable aspect of farmed tuna production, while 29% of people somehow agree that the practice of feeding tuna with wild fish species cannot be considered environmentally sustainable, 43% consider this practice as sustainable and 28% is irresolute.
Finally, considering the environmental issues applying in both wild-caught and farmraised tuna production, three topics were most cited: prevention of plastics from ending up in sea water; implementation of appropriate separate collection of wastes on board; reduction of air emissions and energy consumption.The perception of the environmental sustainability of the (big) fleet size involved in tuna catching is an aspect that creates a more dispersed distribution of answers: around 53% of people consider it as a sustainable aspect, 27% of the sample is irresolute, and finally, 20% of respondents disagree on considering a big sized fleet a sustainable way of catching tuna fish.Another aspect that collects varied opinions is about the catching area of tuna: 45% of people believe that catching tuna only from high seas is a sustainable practice, 24% of respondents are irresolute, while 31% of individuals disagree with the statement.
The value of the interquartile range indicates that the variability of the scores around the median is quite low over all the topics considered, both for those specific to the sources of tuna and for the general environmental issues; the only exception was observed for the fake options whose range reveals a more dispersed distribution of the answers provided by the interviewees.* Legend of scores (5-points Likert scale): totally disagree = 1; partially disagree = 2; nor disagree or agree = 3; partially agree = 4; totally agree = 5.
Females, postgraduates, and aged people showed a higher level of agreement (totally + partially) about the environmental impacts of wild-caught fish (Figure 1A).Regarding the impacts of farm-raised fish (Figure 1B), differences by gender in the level of the agreement are not so strong, while differences according to the education level a ainment are marked and show that individuals with postgraduate education are more convinced of the impacts of farmed fish.Comparing both sources, postgraduate and aged people assign a greater impact on wild-caught than farmed fish production (Figure 1C).In order to deepen the analysis of people's beliefs about the environmental issues related to tuna production, respondents were invited to agree to statements regarding the environmental sustainability of wild-caught tuna production, farm-raised tuna, and some general issues applied in both cases (Table 3).Regarding the internal consistency of items in each statement the results of the Cronbach Alpha suggest that the items have relatively high internal consistency: the consistency of the construct related to the environmental sustainability in wild-caught tuna was measured by a coefficient of 0.837; the reliability of the construct related to the sustainability in farm-raised productions was 0.865; finally, the Cronbach Alpha of the construct about general environmental issues was 0.797.Table 4 shows the cross-tabulation of the correlation linkages between the scores assigned to variables expressing the opinions of the interviewees on environmental issues.As the Table 4 shows, there were several linkages significant at the 10% level or lower, as well as at the 5% level (marked with an *); in addition, the sign of all significant coefficients is positive.In addition, correlations among environmental issues/variables concerning the same sphere (i.e., issues/variables specific to the wild and those specific to the farmed source), and other significant and moderate to high-value coefficients were at the intersections between issues belonging to different spheres.As regards environmental issues specific to the wild-caught tuna, a variable that respondents strongly associated with other issues concerns the respect of the biological reproductive cycle of tuna stocks that is positively related to the problem of by-catch, the protection of deep seas and of the marine species and ecosystems.As regards specific issues of the farmed source, high coefficients involve all the environmental aspects except the issue of feeding fish with wild species which was a fake issue under a sustainable perspective.The environmental issue related to the deep seas and ecosystem protection shows high positive correlations with several other environmental aspects, both in relation to the catching and the farming of tuna, and particularly with the problem of by-catch of endangered species.Finally, as far as general environmental issues are concerned, the problem of plastic outflow into marine waters stands out compared to other issues for the high value of the linkages that associate it with other general impacts, as well as with topics specific to tuna source.Summing up the number of responses in partial/total agreement on overall environmental issues (for the fake aspects, summing opinions totally or partially disagreeing) the total score goes from zero for people that are skeptical over all the issues, to six points for people recognizing the relevance of all environmental issues (Table 5).People who agree on a greater number of environmental impacts (with a score of 4-6) tend to be women, post graduates, and older: this result emerges with regard to the environmental sustainability of wild fish and of farmed production, and even more so with regard to the environmental issues that apply in both cases, in line with results about the general perceptions emerged from Figure 1A-C.
Finally, regarding the opinions on the overfishing status of global tuna stocks, 35% of individuals declare not knowing that percentage.The remaining individuals tend to overestimate the problem: over 36% of the sample believe that overexploited stocks are between 30% and 50%, 26% of individuals consider it to be in the range of 10-30%, and finally, the 3% of respondents are of the opinion that overfished tuna is lower than the 10% of global tuna stocks.In this regard, according to the International Seafood Sustainability Foundation, 22% of the tuna stocks experienced overfishing in the year 2019 [45].

The Environmental Sustainability in Consumers' Tuna Purchasing Choices
Considering the source of tuna, a specific question investigated and compared the wild-caught and the farmed source among consumers' preferences.Results reveal that preferences towards a specific product are quite balanced (17% farm-raised; 18% wildcaught), while 27% of people have no preferences; anyway, 38% of the sample is not able to distinguish between wild-caught and farmed tuna.In relation to this point, 94% of respondents showed interest in knowing the type of canned tuna they buy, if the tuna is wild-caught or farm-raised, thus revealing that they are unaware that the canned product depends on the wild stock.
Moving to the questions involving individuals as consumers, the frequency of canned tuna consumption results as follows: 12% of respondents consume tuna 2-3 times a week; 39% once a week; 22% 2-3 times a month; 16% once a month; and finally, 11% less than once in a month.
A major part of the sample is totally (56%) or partially (30%) in agreement with the statement that "The consumption of sustainable seafood fosters the development of sustainable practices in the seafood sector".About 70% of the sample totally agrees about the responsibility of the individual or of the consumer community in making purchasing choices capable of promoting eco-sustainable fishing practices.
Despite the environmental awareness and concern in fisheries, comparing aspects that respondents most consider when purchasing canned tuna, the commercial brand is at the top of the list (Table 6): 37% of the sample always pay attention to the brand, and another 29% of people often base their purchasing choices on it.The country of origin follows as a factor always or often considered in the purchase of tuna, while all other product characteristics with an "environmental content" are not frequently considered.Reading data differently, when buying canned tuna, our respondents never/rarely considered many aspects that may concern an environmentally sustainable choice: in particular, this is the case of the fishing technique (40%), the presence of ecolabels (35%), the fishing area (34%) and the farming method (32%).

The Test Analysis
In order to investigate the significance of the differences in the distribution of phenomena by demographic and other variables, non-parametric tests (the Mann-Whitney test, for two-sample statistics; the Kruskal-Wallis test, for more than two-sample statistics) were applied.Detailed results for significance at 5% and 10% thresholds are reported in Table 7.
With a threshold of 5% significance level, differences by gender emerged for the following aspects: the knowledge and the concern about environmental issues related to seafood consumption and production; the use of FADs; the attention given to the catching area of the product; and finally, the interest in knowing if tuna fish is wild-caught or farm-raised.All the above phenomena were more perceived among females.The only variable that resulted more associated with the male gender, although with significance at 10%, was referred to the environmental impact of practicing fishing activity in the high sea.
The age of respondents makes the difference in a few items: with a greater perception among the older people, the belief of a greater impact of wild-caught tuna compared to the farmed product and the importance of carrying out fishery activities only on high seas.As far as people's purchasing preferences are concerned, differences by age are in the attention paid to the country of origin (greater among old people) and to the commercial brand of canned tuna (greater among young people).
Regarding the educational level attained by respondents, differences emerged in the opinion that consumption can boost sustainable production paths and about the responsibility of single consumers in driving these processes.Regarding the sustainability aspects, no significant difference emerged about the items related to wild-caught tuna.On the contrary, opinions differ by education in the attention given to the environmental impacts of farmed tuna as regards, the spreading of parasites and the use of antibiotics; about the risks for menaced species and for the deep ecosystems; regarding the environmental impacts related to the plastics in the sea, and the opportunity of the large-sized fleet; and finally, in the attention paid to the tuna specie and the commercial brand in the purchasing choices.With the exception of the belief about the sustainability of big-sized fishing vessels that among individuals with a low education level is considered higher compared to that of the small units, all other phenomena were more perceived among the more educated individuals.
A final set of test analyses referred to the level of knowledge about sustainability and the frequency of canned tuna consumption.Having (greater) knowledge of environmental issues leads to significantly different and highly perceived opinions on several topics: concern for the impacts of fishing and the environmental impacts of wild-caught tuna fishery; about the potential of consumers' pressure towards sustainable productions; over several items measuring the attention paid to the general environmental sustainability of tuna production; and finally, overall environmental items involved in purchasing choices -but not for the commercial brand-, whose attention increases with the level of knowledge.Similar results were obtained by testing the differences in the preference for the origin of tuna, which increases towards the farm-raised product as the level of knowledge increases, but that is not sensitive to other socio-demographic characteristics and frequency of consumption.Finally, the (high) frequency of consumption of canned tuna significantly (and negatively) differentiates over several items: concern and knowledge of the environmental impacts of fishing, and the belief about the pressure of a single consumer in driving sustainable patterns in the tuna fishery; the attention paid to several impacts of wild-caught tuna and of farm-raised tuna; the importance assigned to the separate disposal of waste and to plastics issues.In addition, differences were found in the (increasing) attention given to the fishing technique and the presence of ecolabels when the consumption frequency grows.The increasing consumer concern towards environmental sustainability has stimulated new consumption practices [59].about the potential environmental impact of fishery production is quite high among Italians participating in this study; this result is consistent with what was reported by Cantillo et al. [9] underlying that European consumers are very concerned about the environmental impact of both wild fishing and fish farming.
In this study, participants perceived that in general wild-caught fish is more environmentally impactful than farm-raised seafood.
When considering the environmental aspects that are relevant to wild fisheries, our respondents totally agree mainly with the need of giving attention to the by-catch, of reducing impacts on the marine ecosystems and deep water, as well as of safeguarding the fish reproductive cycle.According to a meta-analysis [12], by-catch is an issue for consumers that prefer wild-caught fish and are willing to pay a moderate premium price for products in order to avoid that issue.
According to our sample, sustainable fish farming should avoid the use of antibiotics.This result is in line with López-Mas et al. [22] findings reporting that European consumers believed that farm-raised fish contains higher concentrations of antibiotics than wild fish.Findings from our Italian sample are consistent with those reported in the study of Claret et al. [32], where Spanish participants perceived farmed fish to be less affected by marine pollution and parasites, while wild-caught fish was considered to have healthier feeding and contain fewer antibiotics.As for the attention put to the plastic litter issue, our results confirmed a previous study among Italians [60].
Information and knowledge about sustainable seafood emerged as important aspects of the study.Indeed, this finding is consistent with those by Lawley et al. [61] who argued that the level of environmental knowledge influences the purchase decision of Australian consumers.Furthermore, Wongprawmas et al. [62] found that subjective knowledge influences the intention of Italian consumers to purchase farm-raised fish; moreover, the level of objective knowledge is not very high, as confirmed by our results.
The study of Claret et al. [63] investigated the relevance of information in the choice of wild-caught versus farm-raised fish and demonstrated that, in informed conditions, Spanish consumers preferred wild fish.Indeed, other studies [64,65] affirmed that several misbeliefs still persist that led consumers to assign wild fish a value higher than farmed fish.These results showing wild-caught preferences are not confirmed in the present study about canned tuna, where the biggest group of individuals are those claiming that they do not have preferences.

Wild-Caught versus Farm-Raised Canned Tuna: Consumers' Preferences
As reported in the literature section, some authors [10,27,63] have shown that consumers prefer wild-caught fish rather than farmed fish which has a less positive reputation among consumers [22].Indeed, Brayden et al. [66] confirmed US consumers' preferences for wild-harvested products but underlined that the magnitude of this preference differs according to the fish product.Regarding the canned tuna considered in our study, the preference for wild versus farm-raised fish does not emerge, although people declare to be interested in having this information.
Our results showed that 56% of the sample was totally in agreement with the statement that "The consumption of sustainable seafood fosters the development of sustainable practices in the sea food sector" even if consumers do not differentiate between the responsibility of a single individual or of consumers' community in making sustainable purchasing choices.Moreover, when purchasing canned tuna, our respondents do not seem highly responsible and do not pay a lot of attention to environmental attributes, especially when these attributes are compared with the commercial brand.This result is also consistent with Allegro et al. [34] that affirmed that concerted efforts should be made to keep (Sicilian) consumers more informed and to guide them to a sustainable fish purchase; furthermore, none of the interviewees indicated the presence of an ecolabel as the main factor driving the purchase of seafood products, a result that is confirmed in the present study that points to the low attention given to both ecolabel and other environmental attributes in canned tuna purchases.
The study of Davidson et al. [36] is interesting for discussing the present study findings in that it specifically addressed the tuna fish preferences, dealing with Hawaiian consumers faced with fresh and canned tuna fish; they indicated that people's purchasing preference for the wild source was higher for the fresh product, while the percentage of people declaring to be indifferent between the tuna source was higher when purchasing canned tuna, consistently with our study findings.
Banovic et al. [67] distinguished consumers' general concern about the sustainability of fish sources from the actual choice behavior.Indeed, our study highlights that individuals show concern about the environmental sustainability of fishing and farming production, but when they are involved as consumers in making sustainable choices in purchasing canned tuna, environmental attributes are not as relevant.This result confirms findings by Forleo and Palmieri [30] showing that, despite the high propensity to buy and pay for certified seafood, Italians' recognition of eco-labels as well as their purchases of certified products are quite low.
Finally, regarding the attention given to the country of origin of canned tuna at the top of the ranking in our study, this result is consistent with the literature affirming that the origin of the product is an important determinant in consumers' decisions on seafood [39,40,[68][69][70].

The Relevance of Socio-Demographic Characteristics
According to some authors, some socio-demographic characteristics could explain consumers' behaviors regarding environmentally friendly products [9,71,72], but others concluded they have limited influence on the purchase decision [21].As reported by Claret et al. [32], the results of this study indicate that consumers' education level, age and gender are associated with significant differences in the perception of both types of tuna sources.
Consistently with our results by age, Bouchard et al. [5] found that older consumers in the Atlantic States were more informed about aquaculture operations and that attention to the presence of product was associated with a lower probability of having a negative attitude toward farmed seafood.
Brécard et al. [73] showed that among Europeans, women, young, and highly educated consumers are more prone to be environmentally oriented.In our case, the results are partly in agreement with the female propensity reported above and indicate that women have a greater concern for the environmental impact of fish production but a lower level of knowledge than men.
The study may suffer some limitations being based on self-reported measures.The snowball sampling method used to select the survey participants may have caused greater participation by subjects aware and concerned about the environmental sustainability of their purchasing behavior.Although the sample was not randomly selected, the results of the study can provide preliminary information that could be useful for implementing marketing strategies focused on the environmental drivers that most influence the purchasing decisions of seafood consumers.A weakness of the study could be attributed to the lack of consideration of additional product attributes driving purchasing choices and of other pillars of sustainability in tuna production; indeed, the environmental attributes and pillars were the specific focus of the study.

Conclusions
Canned tuna is highly produced and consumed worldwide and is among the most consumed fish products in Italy.These circumstances make it important to investigate people's opinions and purchasing choices about the perceived sustainability of wild and farmed tuna sources.
Study results may provide hints to policymakers and producers about people's consciousness of the environmental impacts of fishery and aquaculture and about the most relevant aspects they consider sustainable.These hints could be useful in order to design regulations, tools and marketing strategies that meet Italian consumer interests and better orientate people towards more environmentally sustainable purchasing choices of seafood.
The various attributes that Italians consider relevant for the environmental sustainability of the wild and the farmed tuna, as well as those attributes that drive their purchases of canned tuna, may orientate the management strategies of the operators along the supply chain, increase their commitment to the protection of the environment, and suggest the most relevant context in which they could voluntarily engage in order to satisfy sustainable seafood consumers and be competitive.
From a policy perspective, the beliefs, knowledge and purchasing attributes Italian pay attention to suggest an intervention in several directions.The first direction is in the field of education in order to greatly improve people's knowledge of the relevance of issues relating to the environmental impacts of some fishery and aquaculture methods and techniques.Education equips people with the right tools to make informed and responsible decisions to sustainably use marine resources as a source of food, in line with the so-called Ocean Literacy efforts.Furthermore, policy tools that increase the consumers' knowledge and awareness of the transparency and traceability of the sector, such as standards, mandatory labels and technological innovations, could support more sustainable governance of the fishery and aquaculture sector.
The contribution of the study stays in several aspects.First, it specifically investigates a product, tuna, and does not generalize over all seafood products.Second, the environmental issues that consumers assign to tuna production are investigated by specifically exploring and comparing a list of perceived environmental issues of wild-caught and farm-raised tuna.Third, in addition to consumers' opinions about environmental issues, the study analyses their purchasing choices and which attributes they pay attention to when buying canned tuna.Future research could enlarge the field of investigation both in terms of a wider sample and of sustainable attributes.

Item
Statement/Question Totally Disagree

Partially Disagree
Nor Disagree or Agree Partially Agree Totally Agree

Wild-caught fish impacts
Wild caught fish production may cause environmental impact

Farm-raised fish impacts
Farm-raised fish production may cause environmental impact

Wild > farmed fish impacts
Wild caught fish is more impacting than the farmed fish production

Second Section
How much do you agree or disagree with the following statement?For the sustainability of wild tuna fishing, it is important to take care to:

Marine species impacts
Avoid impacts on species of marine fauna and flora

Reproductive cycle
Respect the natural growth of tuna stocks

Fish discards
Limit product waste or discards of non-commercial fish

By-catch menaced species
Avoid captures of endangered, threatened or protected species

Deep sea and ecosystem
Avoid other damages to the marine ecosystem and the seabed

FADs
Use fish lure technologies to encourage fish schooling (so called Fish Aggregating Devices)

Figure 1 .
Figure 1.(A) Level of agreement about the impacts of wild-caught fish by socio-demographic variables: (a) gender; (b) education level; (c) age.(B) Level of agreement about the impacts of farmraised fish by socio-demographic variables: (a) gender; (b) education level; (c) age.(C) Level of agreement about the greater impact of wild-caught versus farmed fish by socio-demographic variables: (a) gender; (b) education level; (c) age.

Figure 1 .
Figure 1.(A) Level of agreement about the impacts of wild-caught fish by socio-demographic variables: (a) gender; (b) education level; (c) age.(B) Level of agreement about the impacts of farm-raised fish by socio-demographic variables: (a) gender; (b) education level; (c) age.(C) Level of agreement about the greater impact of wild-caught versus farmed fish by socio-demographic variables: (a) gender; (b) education level; (c) age.

1 .
Wild versus Farmed Tuna: Environmental Concern and Issues, Information and Knowledge

Table 1 .
Descriptive statistics of demographic characteristics of the sample (N = 289).

Table 2 .
Beliefs about the environmental impacts of wild-caught and farm-raised fish (%; scores *).

Table 3 .
Respondents' level of agreement about environmental issues in tuna production (%; scores *).

Table 3 .
Respondents' level of agreement about environmental issues in tuna production (%; scores *).

Table 4 .
Correlation matrix among environmental issues in respondents' opinions.
Legend: the table shows only those Kendall's tau-b correlation coefficients that are significant at the 10% level or lower.* highlights all correlation coefficients significant at the 5% level or lower.

Table 5 .
Score of the opinions in partial/total agreement on overall environmental issues by tuna source and socio-demographic variables.

Table 6 .
Attention given to environmental and other attributes in tuna purchasing choices: % distribution of responses.

Table 7 .
Differences in the distribution of phenomena by socio-demographics and other variables.