Understanding Consumer Inflation Expectations during the COVID‐19 Pandemic

Abstract We study how individuals' formation of inflation expectations are affected by the stringent containment and economic support measures put in place during the COVID‐19 pandemic. Using the New York Fed Survey of Consumer Expectations (SCE) and the Oxford COVID‐19 Government Response Tracker (OxCGRT), we find that policies aimed at containing the pandemic lead to an increase in individuals' inflation expectations and inflation uncertainty. We also find some heterogeneity in the impact across different demographic groups.

Introduction
Inflation expectations play a major role in many decisions by households and firms, such as consumption, wage bargaining and price setting. Consequently, they serve as a key input for central banks in their assessments of inflation risks, as de-anchored expectations might result in a persistent rise in prices. This involves the distinction between short-lived spikes and persistent deviations and is especially relevant during periods of stress (such as financial, economic or even health crises) when policy-makers need to make decisions amid unclear economic signals.
At the time of writing, the COVID-19 pandemic continues to pose a threat to a sustained economic recovery in many economies. The response of authorities, for example, in the United States, included instituting stringent containment and health measures, as well as economic support measures. This paper aims to examine the impact of these various government measures on the formation of consumers' inflation expectations. Have these policies helped anchor inflation expectations, or have they instead contributed to a rise in inflation expectations or inflation uncertainty? Answering these questions will provide insights into how expectations are formed in a crisis.
We investigate the behavior of the US inflation expectations, namely the Federal Reserve Bank of New York's Survey of Consumer Expectations (SCE), through February 2021 by using the Oxford COVID-19 Government Response Tracker (OxCGRT) as an indicator of local measures. The implemented measures were not homogeneous, such that we leverage their variation between states and across time to identify their impact on inflation expectations and inflation uncertainty. Our main contribution is that we improve upon Armantier et al. (2021), who examine how inflation beliefs in the SCE evolved over five specific phases during the first six months of the COVID-19 pandemic.
By exploiting the panel dimension of the survey, we find that the effective policies to contain the pandemic lead to an increase in both 1-year ahead inflation expectations and inflation uncertainty. For the 3-year ahead expectations, the results are mixed. At the same time, confirmed cases and deaths contribute little to explaining inflation beliefs. We also examine a cross-sectional dimension of the data with particular attention to demographic aspects such as education and high income. Our results are in line with those of Armantier et al. (2021), suggesting no substantial heterogeneities in the effect of the crisis.
The onset of the COVID-19 pandemic in early 2020 represented a seismic shock for economies worldwide. Lockdown measures such as temporary business shutdowns first indicated a supply-side shock, whereas contagion fears increased uncertainty (Leduc and Liu 2016) and job losses soon led to declines in demand. This resulted in divergent effects on US inflation rates: food prices rose while energy and services inflation fell in the second quarter of 2020. Core inflation measured through PCE inflation excluding food and energy fell from 2.1 per cent in February to around 1 per cent in April 2020. 1 Consumer inflation expectations, on the other hand, had risen at short-and mediumterm horizons since the onset of the crisis (Figure 1). 2 Moreover, there is a notable increase in individual uncertainty ( Figure 2). This reflects consumers' relative inability to clearly quantify what the COVID-19 pandemic would mean for future price developments. One reason could be the confluence of both demand and supply shocks, which rendered the impact on prices to depend both on the magnitude and timing of these shocks. Another reason may be the large change in the composition of consumption baskets following lockdowns, such that consumers are not able to assess the current

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The overall inflation rate (Gautier, Ulgazi and Vertier 2020). At the same time, one needs to consider that respondents have become more polarized with more divergent views on future inflation including deflationary expectations (Armantier et al. 2021). The literature on inflation expectations is extensive and our paper particularly relates to studies analyzing consumer inflation expectation dynamics during the COVID-19 era such as Binder (2020), Dietrich et al. (2020), Coibion, Gorodnichenko andWeber (2020), and Candia, Coibion and Gorodnichenko (2021). 3 The remainder of the paper is structured as follows: Section 2 describes the Survey of Consumer Expectations by the Federal Reserve Bank of New York and the data on state containment policies. Section 3 specifies the econometric model and discusses the results, while Section 4 concludes.

Consumer Inflation Expectations
Each month, the New York Fed Survey of Consumer Expectations 4 is answered by about 1,300 rotating household heads. Households may participate up to 12 months before being substituted. 5 For a discussion of the survey's details and representativeness, we refer to Armantier et al. (2016). Individuals are surveyed about their households' financial and job situation and their expectations of their own future earnings and spending, as well as the economy's future inflation. Our analysis focuses on the questions in which participants rate the odds of certain value ranges of future inflation, for example, the percentage chance that inflation over the next 12 months will be between 2 per cent and 4 per cent, see Appendix A. As a result, participants submit their density distribution of expected future prices at the 1-and 3-year horizon. This provides insights into their range of perspectives and uncertainty around a mean forecast. The SCE further surveys different demographic aspects, allowing us to explore heterogeneity within the panel.
Our analysis starts in April 2015 and includes survey submissions until February 2021. 6 We focus on the individuals' density mean as well as the individual uncertainty calculated as the interquartile range of the individuals' density forecast. Since survey participations are distributed over the entire  Detmers, Ho and Karagedikli: Consumer Inflation Expectations during the COVID-19 Pandemic month, this allows us to link them to current key data of the pandemic.

Containment Policies and Number of COVID-19 Cases and Deaths
Our measures on government responses by US state governments are obtained from the OxCGRT (Hale et al. 2021). 7 The OxCGRT builds upon 17 indicators that are grouped according to their objectives; that is, containment and closure (e.g., school or workplace closing, restrictions on gathering size, etc.), economic response (e.g., income support, debt relief for households, etc.), health systems (e.g., testing policy, vaccination policy, etc.) and others. These indicators are combined into the various composite indices using a simple, additive unweighted method. We focus specifically on the Containment and Health Index (CHI) and the Economic Support Index (ESI). The former shows the number and strength of the measures undertaken to contain the pandemic spread and protect the health of residents. The latter captures the extent of economic support that is implemented to support livelihoods. As shown in Figure 4, there are substantial variations of the indices between US states.
In addition to these indices, the OxCGRT database also provides information about the number of confirmed cases and deaths at the state level. Using this data, we construct 7-day moving averages of the changes in the number of cases and deaths. We include these variables as our state-level explanatory variables in our regression specifications.
Our approach in using state-level containment measure refines the approach employed by Armantier et al. (2021). They identify possible changes during the pandemic by partitioning the post-pandemic data into five periods that are applied uniformly across all states in the United States. However, in reality, the evolution of the pandemic did vary between states. In our approach, we allow for the timing and magnitude of the pandemic to vary across states, depending on the implementation of stringency measures. Thus, we do not need to make ex-ante choices about the timing and evolution of the pandemic.
We match each individual respondent in the SCE by their reported state of residence with the state-specific indicators obtained from the OxCGRT at the given survey date. The unique aspect of our combined dataset is that both the SCE and OxCGRT are available at daily frequency, thereby allowing for a high-frequency estimation of the impact of the policy measures on reported inflation expectations.
Notes: Maximum and minimum lines refer to the maximum and minimum of the index among the 50 US states and the District of Columbia, respectively.

Model
We estimate the following panel data model for the mean inflation expectations and inflation uncertainty of survey participants' density forecasts: (1) where we replace y with it t k e π | + , which is the inflation expectation of the survey participant i at time t for the horizon t + k, where k = 1, 3 years, when we estimate the model for the individual density mean, and with it t k σ π | + for the interquartile range as a proxy for inflation uncertainty. The CHI st is the CHI in state s, the ESI st is the ESI, the gas price rt represents the gasoline prices 8 and π rt is the current inflation rate in the region r of the individual respondent i. 9 The specifications also include confirmed COVID-19 cases and deaths at the state level and control for individual and tenure fixed effects, β i and δ τ respectively. We also controlled for individual's current employment situation, emp it , which could vary during their tenure in the survey.

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The In addition, we investigate heterogeneities by controlling for a range of demographics similar to Armantier et al. (2021) such as age, income, gender, education and health status of individual respondents.
In making a causal interpretation of the impact on inflation expectations and uncertainty, our policy variables to measure the stringency of containment measures are continuous and vary by state, thereby not subject to problems associated with making ex-ante choices about the timing and evolution of the pandemic. However, there could still be remaining confounding factors. For example, the severity and timing of the imposition of the containment measures themselves could depend on the political leaning of the state governments. At the same time, these political leanings could have affected inflation beliefs independently of the containment measures (Bachmann et al. 2021). As a robustness check, we omitted individuals that reside in the five states 10 that flipped from Republican to Democrat at the 2020 US Presidential Election and re-estimated our regressions. Those results (not shown) remain broadly in line with our baseline findings. Table 1 reports the results for 1-and 3-year ahead inflation expectations. The first two columns present the results for mean expectations for 1-year ahead inflation, with column 1 showing the full sample result and column 2 the results from the sample of stayers (individuals who remain for at least 12 survey rounds) only. One of the (non-economic) policy measures, the CHI is statistically and economically significant out of all the major economic variables included in the model. This is the case in both the full and the stayers  (1) and (3) show the results from the full sample while columns (2) and (4) show the results for the individuals who remain in the sample for at least 12 rounds. Coefficients on current employment status are not shown due to space constraints. Standard errors (in parentheses) are clustered at the individual level. *p < 0.1. **p < 0.05. ***p < 0.01. 145 Detmers, Ho and Karagedikli: Consumer Inflation Expectations during the COVID-19 Pandemic only samples. The sign of the coefficient suggests that stronger containment and healthrelated policies correspond with higher 1-year ahead inflation expectations. This may reflect individuals' expectations that these measures would lead to a faster economic and, therefore, faster inflation recovery. Although not reported due to space constraints, the tenure fixed effects also indicate that the mean inflation expectations are lower for participants who stay in the survey for a longer period, suggesting that participants learn from their past participation in the survey and may pay more attention to inflation news and data (Kim and Binder 2021). Columns 3 and 4 of the same table report results for the 3-year ahead inflation expectations. The CHI variable is marginally significant in the full sample and insignificant in the stayers sample, suggesting that the CHI measure is expected to have an effect in the short-term but not in the medium run. Arguably, participants are able to distinguish between the short and medium-term, as the effects of these policies are expected to vanish by the end of the third year from the date of the survey. The results in the full sample are similar to the 1-year ahead responses we discussed above. However, for the sample with stayers only, the CHI variable is not statistically significant. In this sample, the 7-day moving average of confirmed cases turns out to be significant with a negative coefficient. Interestingly, the ESI is not statistically or economically significant.

Individual Density Means
In Appendix B, Table B1 reports results from the specification with a number of interactions for the 1-and 3-year ahead inflation expectations. Some interesting results emerge from these regressions. In the full sample (column 1), the interactions of the CHI with college-educated participants have a negative effect on mean expectations. Participants with a household income above USD100K also report a significantly lower expected inflation 1-year out. On the other hand, people over the age of 60 have a higher mean expected inflation. The health status also plays some role in survey participants' 1-year ahead expectations where people with 'very good' health report significantly lower inflation expectations.

Individual Uncertainty
Next, we run estimations on the respondents' interquartile range at the two horizons to determine what affects people's uncertainty about future inflation. The results are shown in Table 2. An increase in containment measures, CHI, leads to individuals becoming more uncertain about future inflation at both horizons. Hence, it can be assumed that people sense the severity of the pandemic, particularly through the implemented policy measures rather than through actual cases or deaths. The stronger the policies taken by a state, the more uncertain respondents become about the pandemic's impact on future inflation. In terms of the size of the impact, we observe a median increase in inflation uncertainty at the 1-year horizon of one-sixth around mid-April 2020, when containment measures along the states were most extensive, see Figure 3. Hence, at that time, the individual's interquartile range widens by 116 percentage points. This signals a potential deanchoring of inflation expectations and thus reduced trust in the central banks' ability to maintain price stability, see Grishchenko, Mouabbi and Renne (2019), Apokoritis et al. (2019), and Coleman and Nautz (2021). Furthermore, Armantier et al. (2021) show that the increased inflation uncertainty in 2020 already had a significant effect on precautionary savings.
For the 1-year horizon, we do not find a different effect of containment policies in the full sample versus the sample with stayers only. Yet, people who stay in the panel for a minimum of 12 months became slightly more uncertain about prices at the 3-year horizon. Accordingly, stayers assign a wider range of possible outcomes to future inflation three years from now. This is of particular interest, as in general, tenure leads to smaller uncertainty about future inflation (for brevity not shown here, see also Kim and Binder 2021). At the same time, we have seen in Section 3.2 that stayers are not significantly affected by

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The  (1) and (3) show the results from the full sample while columns (2) and (4) show the results for the individuals who remain in the sample for at least 12 rounds. Coefficients on current employment status are not shown due to space constraints. Standard errors (in parentheses) are clustered at the individual level. ***p < 0.01. The ESI reflects the policy measures aimed at mitigating the negative economic effects of the pandemic and the implemented containment measures. However, an increase in ESI does not affect inflation uncertainty. This means that such economic support policies do not create any sense of certainty, at least about future prices. Yet, as shown in Figure 4, there is not too much variation in the ESI such that we might not be able to gauge the entire effect.
As indicated above, the numbers of confirmed COVID-19 cases and deaths affect people's uncertainty about future prices to a much smaller degree. While we find no impact for the 1-year horizon, reactions are significant for inflation uncertainty three years ahead. The daily change in confirmed cases makes people less uncertain about future prices at both horizons, while we find an opposite effect for the change in confirmed deaths. For stayers, the effects are even larger, yet still small compared to the impact of the containment policies. This contrasts with the results by Apergis and Apergis (2021), who analyze break-even inflation and find significant effects of confirmed cases and deaths while they control for oil prices and equity volatility.
In Table B2 in Appendix B, we examine a potential heterogeneity in consumers' reaction to the COVID-19 pandemic, as we did for the individual density means with a particular focus on containment policies.
For the general demographic aspects, in line with Ben-David et al. (2018), we confirm uncertainty decreasing effects for respondents with higher education, increased financial literacy, a higher household income, higher age and male gender, as well as some occupation categories. Specifically, full-and part-time employed people, as well as retirees and early retirees, are less uncertain about future prices. When individuals first enter the survey, they are also asked about their current health. The results indicate that people who consider their health to be merely fair or poor are significantly more uncertain about future prices.
When interacting these demographic aspects with COVID-19 indicators and policies, we find significant results for individuals with high income and college education. Particularly those with a household income The Australian Economic Review March 2022 of above USD100K 11 reveal higher inflation uncertainty at both horizons in response to containment policies. Therefore, these respondents are more uncertain about the potential medium-term effects of pandemic policies and project a wider range of outcomes. By contrast, we find a slight uncertainty decreasing effect for the 1-year horizon for individuals with some college education due to the policies. This indicates that educated individuals expect policies to dampen the effects of the pandemic. Although we expected that those individuals with health issues would respond significantly to the pandemic and the implemented measures, we found no such effect. However, the survey only asks the health question the first time respondents enter and therefore does not allow further conclusions about changes.

Conclusions
We build upon the recent paper by Armantier et al. (2021) by further exploring the effects of the pandemic on individuals' inflation expectations formation. We considered the impact of actual policy measures (i.e., containment policies and economic support) implemented in the different US states on inflation expectations and inflation uncertainty. In this way, we contribute to a better understanding of how consumers perceive crises and crisis policies. We find that, controlling for the actual cases and deaths from the pandemic in a state, the effective containment measures that directly affect all state residents, influence their expectations. These measures lead individuals to expect higher inflation and be more uncertain about future price developments over the 1-year horizon. Over the 3-year horizon, our results are more mixed, with statistical and economically significant effects on inflation uncertainty but not on inflation expectations. Although the measures are aimed at mitigating the pandemic and its negative impact on society and the economy, these actually lead to an increase in short-term inflation expectations and uncertainty. Furthermore, to the extent that higher inflation uncertainty over the medium-term can signal a de-anchoring of inflation expectations, our results show that these policy measures may have longer lasting impact on individuals' inflation expectation formation.
For future research, we highlight the importance of examining the effects of the different types of containment measures. Through that, we can ascertain which type of policy measures are particularly useful for containing the spread of the virus, in tandem with their trade-offs vis-a-vis central banks' mandate in preserving price stability.

Endnotes
1. From about March 2021, the economy then experienced an 'atypical nature of the recovery' (Lagarde 2021) since the rapid reopening of the economy pushed prices upwards. Furthermore, many sectors revealed supplychain bottlenecks that contributed to an increase in inflation. Consequently, the Federal Reserve has recently signalled tightening in policy rates. However, this part of the 'story' is beyond the sample considered in this paper.
2. Note that average consumer inflation expectations in the United States are typically above the Federal Reserve's target of 2 per cent inflation. This bias is not unusual and has been observed in other economies.
3. For a discussion on other measures of inflation expectations, such as by firms and professional forecasters or financial markets, see Meyer, Prescott and Sheng (2021) and Apergis and Apergis (2021). In contrast to consumer expectations, these declined notably with the onset of the pandemic. 4. https://www.newyorkfed.org/microeconomics/sce#/ 5. Over the reviewed sample, about half remain in the panel for the entire possible period.
6. While the panel started in June 2013, some questions such as how participants consider their health conditions were only included later. 7. Sub-national indices for the US states are obtained from this data depository: https://github.com/OxCGRT/ USA-covid-policy. The associated analysis is documented by Hallas et al. (2020). 8. See Binder (2018 for the link between inflation expectations and gasoline prices. 9. The r is the region for gas prices and regional inflation rates, where the boundaries of regions might differ from states, s.    Notes: Other controls include (not shown) regional inflation rates, regional gas prices (annual change), employment status, Economic Support Index. Columns (1) and (3) show the results from the full sample while columns (2) and (4) show the results for the individuals who remain in the sample for at least 12 rounds. Financial literacy is 'high' for respondents who answer at least four out of the five questions on financial knowledge in the survey correctly (see Armantier et al., 2021 for a similar treatment). The baseline characteristics are education at high school level, household income of below USD50K, below 40 years old, female, married, low financial literacy and excellent reported health. Robust standard errors in parentheses. *p < 0.1. **p < 0.05. ***p < 0.01.

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The Australian Economic Review March 2022


A Kettle of Fish: A Review of the Scientific Literature for Evidence of Fish Sentience

Simple Summary Fish are traded, caught, farmed, and killed in their trillions every year around the world, yet their welfare is often neglected and their capacity for feelings is regularly disregarded. We have searched the scientific literature to determine what is known about fish sentience and relate our findings to the many uses of fish around the globe. Abstract Fish are traded, caught, farmed, and killed in their trillions every year around the world, yet their welfare is often neglected and their sentience regularly disregarded. In this review, we have sought to (1) catalogue the extent to which fish sentience has featured over the past 31 years in the scientific literature and (2) discuss the importance of fish sentience in relation to their commercial uses. We searched the journal database Science Direct using 42 keywords that describe traits or elements of sentience to find articles that were referring to or exploring fish sentience. Our review returned 470 results for fish sentience in 142 different species and subspecies of fish, and featured 19 different sentience keywords. The top four keywords were; ‘stress’ (psychological) (n = 216, 45.9% of total results), ‘anxiety’ (n = 144, 30.6%), ‘fear’ (n = 46, 9.7%), and ‘pain’ (n = 27, 5.7%). Our findings highlight an abundance of evidence for fish sentience in the published scientific literature. We conclude that legislation governing the treatment of fish and attitudes towards their welfare require scrutiny so that their welfare can be safeguarded across the globe.

Introduction
Fish are experimented upon, traded, caught, and farmed in numbers far outweighing any other vertebrate taxa [1]. Currently, fish represent over half of the vertebrate species in the wildlife trade and had an estimated worth of US$180 billion in 2018 [1,2]. The commercial fishing sector is so vast that fish harvested from the wild are typically recorded by weight, rather than numbers of individuals [3]. Records generally do not account for the numbers of fish that are caught as by-catch or in ghost fishing gear [4]. Animals caught in abandoned fishing gear or in fishing nets as by-catch can suffer extensive injuries and slow deaths as a result [5][6][7].
Although most fish involved in the wildlife trade are destined for consumption (both for subsistence and commercial use), many are also caught, farmed, and traded as pets, an industry that has seen significant growth in recent years [2,8]. Figures regarding the scale of the fish pet trade remain unclear, as much is unmonitored and unregulated, and few scientific analyses have attempted to quantify the numbers involved [2]. Fish are also increasingly used for scientific research. The past 20 years, for example, have seen a steep rise in the number of zebrafish (Danio rerio) used as models for various human diseases e.g., [9][10][11] for developing pharmaceutical drugs [12], and in aquaculture nutrition research e.g., [13]. In addition, fish are used in tourism, including ray petting and sport fishing, where they may be subject to a range of welfare issues [14][15][16]. Fish are also traded for traditional medicines and belief-based use [17,18]. Seahorses, for example, are one of the most widely traded taxa for traditional medicines [19], with thousands of metric tonnes of their bodies traded into and out of China for this purpose each year [20]. Aquaculture has also grown exponentially in terms of the numbers of fish involved [21], and although domesticated species of fish are typically used, wild fish are also involved, as new species are continually being targeted for farming. Millions of tonnes of fish are also wild-caught to feed farmed fish and domesticated livestock every year [21,22].
Despite their wide uses in the wildlife trade, legislation protecting fish has been described by some researchers as inadequate, including for experimentation, trade, and aquaculture [23][24][25]. Nevertheless, some efforts to develop protocols for fish welfare are being seen in response to the increasing use of fish in translational research and aquaculture [26]. The disparity still seen in legislation, however, is in part due to doubt and ignorance regarding the capacity of fish to feel pain and suffer [27,28], and many consumers and policymakers still consider fish to have little capacity for subjective experience [23,28,29]. For example, fish often score low on belief in animal minds surveys compared with other vertebrates such as mammals and birds [30,31]. The capacity of fish to feel pain has been questioned historically, potentially because there are significant economic implications associated with acknowledging this [32]. Specifically, some argue that the entire commercial fishing model is based upon the idea that fish do not suffer and therefore do not need to be slaughtered, but can be left to asphyxiate instead [33,34].
Inadequate protection for fish applies to both welfare and conservation concerns, as fish and other less charismatic taxa, such as invertebrates and amphibians, have not always received the same level of attention from policy forums as other vertebrates have. For example, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) currently lists only 16 species of fish in Appendix I, despite 15,000 species being traded globally, around 20% of which are threatened with extinction [35,36].
In this review, we have sought to address these issues by examining the scientific literature to quantify the extent to which fish sentience has been recognised, utilised, or experimentally explored. For the purpose of this review, we define sentience as the capacity to have feelings, but have used a list of 42 different keywords to encompass all aspects of sentience. In this review, we have (1) catalogued the extent to which fish sentience featured over the past 31 years in the scientific journal database Science Direct, both in terms of sentience traits and the species involved, and (2) discussed the findings concerning the extensive involvement of fish in the various industries that impact them.

Methods
We searched the scientific literature for evidence of sentience in fish. As the term sentience is complex, and the traits and characteristics of sentience may manifest themselves in different ways, we used a list of 42 keywords to define sentience (Supplementary File S1). The keywords were derived from previous reviews we have performed exploring sentience in all animals [37], reptiles [38], insects [39], and amphibians [40]. Because of the scale of this current review, we only searched for the keywords that had returned results in the previous four reviews. We also added two additional keywords, namely 'intentionality' and 'prosocial', to encapsulate additional aspects of sentience that were not used in the previous reviews.
We used the 42 keywords to search through the journal database Science Direct. We performed the searches using the search term 'fish', along with the Boolean operator 'AND', and then each of the keywords in turn. As some fish genera are not commonly referred to as fish and would therefore be unlikely to come up when searching for 'fish', we performed additional searches to ensure that we covered as many species of fish as possible. Therefore, we also searched for 'seahorse', 'eel', 'shark', and 'ray', along with each of the sentience keywords. We performed 210 searches in total. Each of the articles was reviewed against a set of criteria. Those that met all five of the criteria were included in the results as a returned article. The criteria were that the article (1) had to be published between 1990 and 2020, (2) be a research article, (3) utilise one or more species of fish in an experiment, (4) use the keyword regarding the fish species being studied in their experiment and not a previous study, and (5) use the keyword in relation to the fish's subjective state. For example, the keyword 'stress' had to be used regarding the emotional or subjective experience of stress, and not oxidative or thermal stress. Some articles referred to more than one keyword or species, and we treated these as individual results, providing they met the criteria. We focused on the timeframe of 1990-2020 in order to cover a large selection of research within the time constraints that we had. The research was performed in 2021 to ensure that 2020 was a complete year.
We reviewed all the results to establish how the keyword was used regarding the fish species. Each returned result was categorised as either 'assume' or 'explore', depending on whether the keyword was accepted or being experimentally explored. For example, a study that 'assumed' that parrotfish can experience pleasure would use the keyword in their experiment to test whether parrotfish found one thing more pleasurable than another, whereas a study that was 'exploring' whether fish can feel grief would test to see whether they showed behavioural and physiological signs of grief in an experimental paradigm. We recorded the 'explore' results as either positive, negative, or inconclusive, depending on the study's authors' reported outcome. If they found positive evidence of the keyword they were exploring, then we recorded it as a positive result. If they found evidence that the fish species did not have the characteristic or trait they were exploring, then we classed it as negative. We recorded ambiguous findings as inconclusive.
We then recorded the article's title, publication year, and journal name for each result, along with the scientific name and common name of each of the relevant species, and their taxonomic order(s). To maintain consistency, following the initial searches, one researcher reviewed all the returned articles against the criteria to determine which articles were to be included in the review.

Additional Criteria
In addition to the five criteria mentioned earlier, some keywords were subject to additional criteria due to their use. The keywords 'stress', 'distress', and 'suffer' were commonly mentioned in relation to ethical procedures or regulations that the study had to adhere to. For these keywords, we only included the article if the keyword was used directly about the fish species being studied and not used only as a sweeping statement. For example, if the study stated that 'care was taken to reduce distress in the zebrafish', then it was included as it referred specifically to the fish species. However, if it stated that 'care was taken to reduce distress in the animals used in the experiment', this phrase was considered to be too general, as it did not refer specifically to the fish species used and, therefore, did not fit the criteria for inclusion.
Science Direct caps the results it displays to a maximum of 6000. The keyword 'stress' was the only one to return over 6000 results (92,695 results). Therefore, we could only view the first 6000 of these results (organised by relevance).

Inter-Rater Reliability Tests
Two of the authors collected the data, and both had previously performed a similar systematic review using many of the same keywords [37]. Both researchers conducted two inter-rater reliability tests [41] before and after the data collection period. For each of these tests, both researchers reviewed the same six articles and recorded whether the keyword was used correctly for each and whether it was explored or assumed. Each test used three randomly selected keywords, and a different selection of six articles was used for each test. The lead researcher's analyses served as the gold standard throughout training and for all comparisons. We then compared the researchers' responses with each another and calculated a percent agreement. Both tests returned a 100% agreement score.

Data Analysis
We performed descriptive analyses (totals and percentages) on the returned results using Microsoft Excel Version 2110.

Results
In total, 470 results were returned across 349 articles. Some articles mentioned more than one keyword or utilised more than one species of fish, and we recorded those as individual results.

Data Analysis
We performed descriptive analyses (totals and percentages) on the returned results using Microsoft Excel Version 2110.

Results
In total, 470 results were returned across 349 articles. Some articles mentioned more than one keyword or utilised more than one species of fish, and we recorded those as individual results.

Sentience Keywords
Of the 42 sentience keywords we searched for, 19 returned results (see Figure 1). The top four keywords returned were 'stress' (n = 216, 45.9% of total results), 'anxiety' (n = 144, 30.6%), 'fear' (n = 46, 9.7%), and 'pain' (n = 27, 5.7%). The graph shows the number of times each keyword was studied in fish across the 349 returned articles published between 1990 and 2020, and whether the keyword was accepted in the study ('assume') or was being experimentally explored.

Taxa Returned
Of the 470 results, 75.3% (n = 354) were returned using the search term 'fish' (along with each of the sentience keywords), 15.1% (n = 71) were returned using the search term 'shark', 1.7% (n = 8) were returned using the search term 'seahorse', and 0.6% (n = 3) were returned using the search term 'eel'. The search term 'ray' did not return any appropriate results.  The graph shows the number of times each keyword was studied in fish across the 349 returned articles published between 1990 and 2020, and whether the keyword was accepted in the study ('assume') or was being experimentally explored.

Taxa Returned
Of the 470 results, 75.3% (n = 354) were returned using the search term 'fish' (along with each of the sentience keywords), 15.1% (n = 71) were returned using the search term 'shark', 1.7% (n = 8) were returned using the search term 'seahorse', and 0.6% (n = 3) were returned using the search term 'eel'. The search term 'ray' did not return any appropriate results.
In total, 142 different species and subspecies of fish were returned (Supplementary File S2), representing 30 different fish orders (see Figure 2). The top three orders returned were Cypriniformes (ray-finned fish such as carp and zebrafish; n = 185, 39.3% of all results), Salmoniformes (ray-finned fish such as salmon and trout; n = 60, 12.9%), and Perciformes (ray-finned fish such as perch and cichlids; n = 51, 10.8%). The top three species featured were zebrafish (Danio rerio, n = 120, 25.5% of all results), rainbow trout (Oncorhynchus mykiss, n = 45, 9.5%), and Nile tilapia (Oreochromis niloticus, n = 15, 3.1%). The graph shows the number of times each order featured in studies published between 1990 and 2020 that either assumed or explored sentience in fish, along with the most frequently returned types of fish that featured for each order.

Explore/Assume
Only the keywords 'anxiety', 'depression', and 'pain' were explored (see Figure 1). 'Anxiety' was explored once with a positive outcome involving piauçu (Leporinus macrocephalus). 'Depression' was explored three times, with two positive results, both involving zebrafish (Danio rerio), and one inconclusive result involving zebrafish. 'Pain' was explored six times with five positive results involving common carp (Cyprinus carpio), goldfish (n = 2 Carassius auratus), and rainbow trout (Oncorhynchus mykiss), and one inconclusive result involving zebrafish. The remaining keywords were all assumed. The graph shows the number of times each order featured in studies published between 1990 and 2020 that either assumed or explored sentience in fish, along with the most frequently returned types of fish that featured for each order.

Explore/Assume
Only the keywords 'anxiety', 'depression', and 'pain' were explored (see Figure 1). 'Anxiety' was explored once with a positive outcome involving piauçu (Leporinus macrocephalus). 'Depression' was explored three times, with two positive results, both involving zebrafish (Danio rerio), and one inconclusive result involving zebrafish. 'Pain' was explored six times with five positive results involving common carp (Cyprinus carpio), goldfish (n = 2 Carassius auratus), and rainbow trout (Oncorhynchus mykiss), and one inconclusive result involving zebrafish. The remaining keywords were all assumed.

Journals
The 349 returned articles were published in 64 different journals in the Science Direct database. The three journals featuring the most articles were Aquaculture (n = 41,  11.7% of all articles), Behavioural Brain Research (n = 37, 10.6%), and Physiology and Behavior (n = 27, 7.7%). Figure 3 shows the number of returned articles from each of the publication years reviewed (1990-2020). Overall, there was an increasing trend (R 2 = 0.881) in the number of articles featuring fish and the sentience keywords being published each year.

Journals
The 349 returned articles were published in 64 different journals in the Science Direct database. The three journals featuring the most articles were Aquaculture (n = 41, 11.7% of all articles), Behavioural Brain Research (n = 37, 10.6%), and Physiology and Behavior (n = 27, 7.7%). Figure 3 shows the number of returned articles from each of the publication years reviewed (1990-2020). Overall, there was an increasing trend (R 2 = 0.881) in the number of articles featuring fish and the sentience keywords being published each year.

Discussion
Despite the common misconception that fish cannot feel pain or that their feelings do not matter, there is plenty of evidence demonstrating the importance of considering fish sentience e.g., [25,[42][43][44]. In this review, we found evidence of fish sentience across the scientific literature, and that fish are commonly recognised as being capable of experiencing a range of emotional states. Specifically, we found 470 references to sentience traits in fish across 349 different articles published between 1990 and 2020. The results involved 142 different species and subspecies of fish (from 30 different taxonomic orders) and spanned across 19 different sentience keywords, representing a range of subjective states in fish, from altruism to stress. Of the 10 results (eight articles) that explored sentience in fish, eight positively identified evidence of pain, depression, and anxiety; the other two were inconclusive (for pain and depression). Our review has highlighted the considerable number of studies that have utilised aspects of fish sentience in experiments. Fish sentience is a growing field of research, as we found a positive exponential growth trend (R 2

Discussion
Despite the common misconception that fish cannot feel pain or that their feelings do not matter, there is plenty of evidence demonstrating the importance of considering fish sentience e.g., [25,[42][43][44]. In this review, we found evidence of fish sentience across the scientific literature, and that fish are commonly recognised as being capable of experiencing a range of emotional states. Specifically, we found 470 references to sentience traits in fish across 349 different articles published between 1990 and 2020. The results involved 142 different species and subspecies of fish (from 30 different taxonomic orders) and spanned across 19 different sentience keywords, representing a range of subjective states in fish, from altruism to stress. Of the 10 results (eight articles) that explored sentience in fish, eight positively identified evidence of pain, depression, and anxiety; the other two were inconclusive (for pain and depression). Our review has highlighted the considerable number of studies that have utilised aspects of fish sentience in experiments. Fish sentience is a growing field of research, as we found a positive exponential growth trend (R 2 = 0.881) in the number of scientific studies that have assumed or explored fish sentience over the past three decades.
It is important to note that the majority of the results returned in our review were 'assuming' sentience traits in the fish species being studied. We do not feel that this is a concern in regards to evidence of fish sentience being unproven, as the same bias was found across other taxa, including mammals, in our previous review [37]. Furthermore, due to the limited scope of our review, we cannot say whether or not these keywords have previously been explored elsewhere in fish species, or what the assumption of the sentience trait was based upon. It is highly likely that, as with other vertebrate taxa such as mammals, the basis for these 'assumptions' comes from a mix of empirical evidence, behavioural responses, and the physiological and neurological indicators underlying the sentience trait in question.
Most of the results (75.4%) were returned when searching for 'fish', although some groups of fish were not featured in these searches; none of the results returned under the 'eel', 'shark', 'seahorse', or 'ray' searches were recorded in the generic 'fish' searches. The search term 'ray' returned no appropriate results, whereas 'seahorse' returned eight, 'shark' returned 71, and 'eel' returned three results, all of which were 'assumed'. Overall, we found no evidence of an absence of sentience in fish. Instead, our findings highlight the capacity of fish to feel important subjective states, such as pain, depression, and anxiety, and positive evidence of the capacity of fish to experience these states. As research shows that fish are capable of a range of emotional states and feelings such as pain [28,41,44], our findings have important implications for fish, both wild-caught or farmed for use as pets, scientific purposes, traditional medicine, or consumption, as the associated welfare issues can be considerable and deserve attention [23,25,45].

Fish
The sentience keywords 'stress', 'anxiety', 'fear', and 'pain' returned the most results, both when searching for 'fish' and overall (see Figure 1). This is unsurprising, given that fish, particularly zebrafish, are regularly used as models of anxiety and stress [46]. Given that some researchers question whether or not fish feel pain, e.g., [47], it is interesting to see that 'pain' was assumed in fish 21 times, including once for eels [48], in 20 different studies and in eight different fish species. 'Pain' was explored in six cases, five of which had a positive result and concluded that the species studied (common carp, rainbow trout, and goldfish) could feel pain. One study had an inconclusive result [49], as they did not have definitive evidence for pain in zebrafish. However, they did have a positive result for pain in common carp and rainbow trout.
Other keywords returned in our review included 'affective state', 'emotion', and 'sentience', all of which were assumed in European minnows (Phoxinus phoxinus), rainbow trout (Oncorhynchus mykiss), seabream (Sparus aurata), zebrafish (Danio rerio), and convict cichlids (Amatitlania nigrofasciata). In one study, both 'emotion' and 'sentience' were assumed in rainbow trout and were used as the basis for designing welfare measures for aquaculture [50]. In the study, the fish that were subjected to poor water quality (the stressed group) were less able to cope with aversive experiences (such as social isolation and human presence), showed spontaneous behavioural differences, and had diminished cognitive abilities compared with the control group. These findings have considerable implications for the many uses of fish. The water conditions for some commonly farmed fish species, for example, are often considered to be poor due to overcrowding and inadequate husbandry measures [51]. Similar issues are found for fish transported for the pet trade, as the duration of time they are kept in small containers can negatively impact water quality and severely restrict their natural behaviour [8].

Sharks
'Stress' was the only keyword that returned suitable results for sharks, and all 71 results were assumed across the 40 species featured (Supplementary File S2). Sharks are affected directly by the fishing industry, as they are targeted for their fins [52] and meat [52], and are often caught in nets as by-catch [53]. Mortality rates for sharks released after being caught as by-catch are typically high, which is thought to be due to stress caused by the experience [54]. One study we reviewed examined the post-release survival and behaviour of juvenile tiger sharks when caught in long-line fishing gear [55]. They found that the stressfulness of the experience resulted in behavioural changes in sharks, and suggested that the subsequent deep-diving that the sharks performed for the days after release was a direct response to the stress caused by being hooked, and that the sharks were deliberately avoiding the shallower waters.

Rays
Our searches for 'ray' returned no suitable results. Rays are often caught as bycatch; fished for the pet trade, consumption, and recreation; and for their skins [56,57]. Some species of rays, such as stingrays, are also used in research [58]. However, there is very little understanding regarding what constitutes good welfare for rays during capture or captivity. To our knowledge, no studies have explored the welfare of rays kept as exotic pets or in the preceding stages of trade, and it appears there are no strategies in place to ensure their welfare during commercial fishing, despite the apparent rise in interest in their skin for leather products, their meat, and the capture of live rays for the exotic pet trade [56,59,60]. Stingrays are becoming increasingly popular pets, and some species are sold for over USD 500 [61]. As they are unsuited to home aquariums, owners often release their stingrays into waterways once they outgrow their captive environment, which can pose a risk to native aquatic species [59,61]. Rays also feature in public aquariums, where people can stroke and interact with them. Despite this, we found no reference in the scientific literature on their welfare during these interactive experiences.

Eels
'Pain' and 'stress' were the only keywords that returned results for eels, both of which were assumed in the two studies (pain: n = 1; stress: n = 2), and all three results featured the European eel (Anguilla anguilla). One study concerned the welfare implications of live chilling and freezing of farmed eels, and tested the time it took eels to reach unconsciousness, based upon ECGs and their pain responses [48]. Eels are both farmed and wild-caught for consumption and breeding, and may be exposed to many stressful and painful experiences, including injuries and mortalities as a result [62]. Little is known scientifically about the subjective experiences of eels, but evidence of their capacity to feel pain and stress means that their welfare deserves more attention.

Seahorses
Our results show that seahorses are assumed to be capable of anxiety, distress, fear, and stress, which are all highly relevant emotional states in terms of their use in the pet trade, in scientific research, and as traditional medicine. The main two markets for seahorses are the trade of dried seahorses for traditional Asian medicine [20], which comprised an estimated 5.7 million individuals between 2004 and 2011 [63], and the trade of thousands of live seahorses for the pet trade [64]. There is currently very little in the scientific literature regarding the welfare of seahorses in both of these markets. Therefore, more research is needed, particularly when considering the extent of their trade and that they are assumed in research to have the capacity for emotional states such as distress and fear. In one study we reviewed, lined seahorses (Hippocampus erectus) showed both behavioural and physiological stress and distress responses to chronic noise exposure, compared with when they were kept in a quiet tank [65]. These findings have direct consequences for the welfare of the thousands of individual seahorses traded as pets, as the transportation and subsequent captivity may well involve exposure to chronic noise, representing a significant welfare concern.

Limitations
Our literature review was not intended to be exhaustive, but highlighted what scientists accept and are actively researching regarding fish sentience. Given the broad scope of the terms that we used (fish, seahorse, eel, shark, and ray) and the fact that we searched the Animals 2022, 12, 1182 9 of 13 full text of the articles, it is likely that we found the vast majority of relevant Science Direct articles, although we may still have missed some studies.
The sentience keyword 'stress' returned over 90,000 research articles. Unfortunately, because Science Direct only allows one to access the first 6000 articles (organised by relevance), we could only review and include the relevant articles from the first 6000, rather than the full cohort of studies referring to stress. As a result, it is likely that the total number of returned articles and results for the keyword 'stress' are far higher than we have found.

Future Research
Given that there are around 32,000 extant species of fish [23], adopting a speciesspecific approach for reviews such as this is unfeasible. Future reviews and research into fish sentience could focus on species that are utilised, traded, farmed, or caught in extensive numbers to develop our understanding of the complex welfare needs of fish, and the relevance and application of these to their use in various industries. For example, stingrays are growing in popularity as pets [59] and are sought after for their skins [56], and eels are widely caught and farmed for consumption [48]. However, our review found little research into the subjective minds of eels and rays, and so more research into their welfare needs is important.
Our review primarily returned sentience keywords that are concerned with negative states and experiences such as pain, stress, and fear. Animal welfare science increasingly recognises the importance of positive states and experiences for captive animals [66]. Our review highlights that there is currently a lack of either acknowledgement or utilisation of positive states in fish in scientific research. This may be because many do not consider fish as capable of positive experiences or states such as joy, pleasure, and play, or it may be because these keywords were not relevant to the types of research that fish are commonly used for.
Discussions and research into fish welfare are still very much lacking, especially compared with other vertebrates [24,37]. Even with the rise of aquaculture, progress has been criticised as being 'exceptionally slow' in addressing major welfare issues such as slaughter, handling, disease, and stocking densities [23]. It is unsurprising, therefore, that positive experiences and feelings in fish are relatively unexplored, as they have only recently become a concern for other vertebrates in the past decade [37,66]. However, if we are to maximise the welfare of fish in laboratories, home aquariums, or aquaculture facilities, then more research is needed into both positive and negative experiences in fish, how they affect fish welfare, and what fish need to have a good life.
Another important direction for future research should be on how to improve public attitudes to and perceptions about fish. Fish are commonly viewed merely as commodities and are typically described in terms of volume or weight, rather than the numbers of individual fish who are bred, caught, and killed [3,24,27]. Pet fish are also commonly viewed as disposable and are often simply replaced when they are ill, rather than treated [67,68]. As a result, the treatment of fish in many contexts can be poor, whether they are left to die, killed in inhumane ways, or kept in inadequate environments with little or no regard to their behavioural or environmental needs [22,23,34,68].

Additional Recommendations
Research on the impacts of trade on fish welfare is needed to make informed ethical judgements relating to policy decision-making (e.g., changes to how trade is conducted or prohibiting certain practices). Based on our findings that highlight the complexity and diversity of fish sentience, we recommend that if fish continue to be bred, traded, and caught, then the legislation governing these practices should be evaluated, improved, and enforced, taking fish sentience into full account. Where certain practices are already prohibited, such as shark finning for certain species [69] and electrical pulse fishing in the European Union in 2021 [70], these bans must be properly enforced to be effective.
Industries using fish, such as aquaculture, are growing exponentially [3], and some areas of welfare, such as slaughter practices, have benefitted from scientific attention [71][72][73]. Despite this, other areas are relatively disregarded, such as the millions of tonnes of wildcaught fish used for feeding farmed fish each year [21], and the welfare issues associated with their capture and death [34]. Fish are utilised in their trillions every year, so it is time that their sentience is properly recognised, and that practices and legislation affecting fish seek to safeguard fish welfare.

Conclusions
Our review has highlighted evidence of fish sentience in the scientific literature, but what does this mean in terms of the practices that impact the welfare of fish? According to the International Union for Conservation of Nature (IUCN), around a third of vertebrate species listed under the category 'Use and Trade' are fish [74], yet fish are rarely given much consideration in terms of legislative protection [23]. Fish are wild-caught and captive-bred for aquaculture, scientific research, traditional medicine, and the pet trade in vast numbers, yet little is known about how best to ensure their welfare and provide for their needs [75]. Furthermore, fish are a diverse group of animals, from seahorses to sharks, and what is considered acceptable by society is influenced by the type of fish in question. Shark finning, for example, is generally considered to be inhumane and criticised by the Western world as cruel, unnecessary, and wasteful, and there is legislation governing the practice, albeit widely considered to be ineffective [69]. However, practices in commercial fishing, such as leaving fish to die by asphyxiation, are commonly overlooked by society and in legislation, despite also being an inhumane practice [34].
Understanding more about the sentience of fish and publicising the scientific knowledge of fish sentience are crucial in changing both the public's and industry's attitudes and ultimately behaviour towards these animals. It is clear from our review that fish are already widely accepted as being capable of a range of sentient traits, yet practice and legislation do not always properly reflect this [23]. Targeted research that seeks to highlight the sentience of fish and how it relates to their welfare needs is therefore still needed.