How to Sustain Fisheries: Expert Knowledge from 34 Nations

: Ensuring productive and sustainable fisheries involves understanding the complex interactions between biology, environment, politics, management and governance. Fisheries are faced with a range of challenges, and without robust and careful management in place, levels of anthropogenic disturbance on ecosystems and fisheries are likely to have a continuous negative impact on biodiversity and fish stocks worldwide. Fisheries management agencies, therefore, need to be both efficient and effective in working towards long-term sustainable ecosystems and fisheries, while also being resilient to political and socioeconomic pressures. Marine governance, i.e., the processes of developing and implementing decisions over fisheries, often has to account for socioeconomic issues (such as unemployment and business developments) when they attract political attention and resources. This paper addresses the challenges of (1) identifying the main issues in attempting to ensure the sustainability of fisheries, and (2) how to bridge the gap between scientific knowledge and governance of marine systems. Utilising data gained from a survey of marine experts from 34 nations, we found that the main challenges perceived by fisheries experts were overfishing, habitat destruction, climate change and a lack of political will. Measures suggested to address these challenges did not demand any radical change, but included extant approaches, including ecosystem-based fisheries management with particular attention to closures, gear restrictions, use of individual transferable quotas (ITQs) and improved compliance, and control.


Introduction
For the second half of the twentieth century, scientific and technological endeavours focused on finding new fisheries to exploit and more efficient and effective ways of harvesting. This was possible as developments in vessel and gear design, navigation and positioning systems and means to detect fish (e.g., depth-sounders) became more accessible to the common fisher [1]. These scientific and technological advances led to a dramatic increase in global fishing effort. Such developments also allowed fleets to exploit more distant resources to the point where the only unexploited fishery resources were those that remained physically inaccessible, for example under sea-ice [2]. For much of this period, much of the sea was treated as a common resource with many fish stocks exploited with little restriction and only a few with strict governance, setting conditions for a "tragedy of the commons" [3]. In recent decades, there has been increasing awareness of the need for global political management recommendations based on their findings, ultimately management decisions are made by government officials and politicians. Importantly, these decisions are not driven only by scientific knowledge of the stock and dynamics of the ecosystem in which a fishery is embedded, but also by a range of political agendas and economic, social and cultural considerations. While scientists may be frustrated with this reality, it is important for them both to accept that they are only one voice at the decision-maker's table, but also not to shy away from objectively presenting the scientific evidence.
Given that there are many environmental, biological and socioeconomic factors that ultimately affect the state and health of the oceans, and that these drivers vary in time and space, decisionmakers increasingly ask whether there is sufficient scientific information and knowledge of ecological functions and processes to implement an ecosystem approach to marine and fisheries management [31]. Successful marine management needs careful integration across sound scientific knowledge, development and implementation of management instruments and compliance tools. Even though there are many ecological processes to understand further, it is widely recognised that we do have sufficient scientific information to start implementing EBFM in many places around the world [32][33][34].
One challenge to implementing EBFM is that ocean resources are often managed sector-bysector, i.e., coastal and terrestrial development, water management, environment conservation and primary industries (including fisheries) are each managed by separate jurisdictions [31]. The different set of goals and objectives within each sector may have implicit trade-offs so that fisheries managers often need to navigate and respond to conflicting objectives and incentives involving two or more government agencies [35,36] or interest groups. Clearly, if there is a negative impact on marine habitat due to fishing gear as well as from toxic terrestrial run-off, then both the fishing sector and the land-use sector need to take appropriate actions to prevent further habitat degradation [37]. Implementing EBFM, or EBM, requires a governmental organisational structure that matches this holistic view of ecosystem-based management. This does not immediately dictate an overarching, allencompassing regulatory body, but it does necessitate communication (and where possible harmonisation of requirements) between agencies.
While defining the final scope of an ecosystem-based management governance system is beyond the scope of this paper, providing information on the current state of play is important to understanding what steps are still required to achieve solid advances. This research explores the main issues influencing the sustainability of fisheries. It draws on data derived from an international survey of fisheries experts, using the elicited responses to (1) identify the main issues in attempting to ensure the sustainability of fisheries, and (2) address how to begin to bridge the gap between scientific knowledge and the governance of marine systems, from the point of view of fishery management experts. The survey data were analysed to explore expert insights, opinion and understanding on the challenges to sustainable fisheries, the efficacy of tools used to manage fisheries and the complexity of interactions in fishery socioecological systems.

Data Collection
We targeted marine experts from around the world, primarily scientists and natural resource managers. Our survey was designed to elicit knowledge from marine scientists, managers, fishers and policy-makers. The intention was to gather specialist knowledge and experience in relation to sustaining fisheries. The survey was implemented by inviting experts to share their knowledge and experiences at the 6th World Fisheries Congress in Edinburgh, 8-11 May 2012. Attendees were invited to sit down at a booth and take part in the web-based survey. If an individual did not have time to conduct the survey when approached, they were given the opportunity to complete the survey in their own time either online or via a hard-copy of the survey. In total, 549 persons were invited to participate in the survey, resulting in 168 fully completed surveys (20 more provided partial completions that were still sufficient for inclusion in the analysis), giving a 34% response rate.

Analysis
The questions and a summary of the answers are presented in Appendix A. Given small sample sizes when respondents were broken down by category, for some questions, the responses from fisheries/natural resource managers and policy-makers were aggregated into a 'managers/policy makers' group. For the same reason, variables measured on five-point response scales were, in some cases, converted into a three-point scale. For example, the five-point 'satisfied-dissatisfied' scale was in some cases collapsed into the categories 'satisfied', 'neutral' and 'dissatisfied', by combining 'satisfied' with 'very satisfied', and 'dissatisfied' with 'very dissatisfied'.
Statistical analyses, including crosstabulations, were conducted using SPSS (Version 25.0., IBM Corp, Armonk, NY, USA). No corrections were made. The statistical independence of pairs of variables was analysed using the 2-factor G-test for independence at a 95% significance level.

Demographics
The respondents were from 34 nations, representing scientists, fisheries managers, fishers, policy-makers, NGOs and others. Forty (40) respondents were from Australia, as the survey was trialed there before presenting it at the World Fisheries Congress.
Seventy-one percent of the respondents were male, and 60% of the respondents were 35-64 years old (Appendix A). Forty-two percent of the respondents had a Doctoral degree, 28% a Master's degree, 14% a 3-4 year university degree, and the remainder did not hold a degree, but all had completed high school (Appendix A). The majority of the respondents were scientists (Figure 1), with fifty-nine percent of the respondents holding a degree in marine science and 20% in environmental science. Other respondents had degrees in business, law, economics and social sciences (Appendix A). The majority of the respondents spanned middle-executive management positions, and represented pelagic, demersal, coastal and crustacean fisheries (Figures 2 and 3). The respondents represent experience and knowledge from fisheries deemed to be sustainable as well as from overfished, collapsed, recovering and exploratory fisheries ( Figure 4). Of the respondents, 47% worked with national management agencies, 24% with international management and 15% at universities (Appendix A).

Fisheries status
Overfishing, climate change and habitat destruction were believed to be the three threats most affecting fisheries, both at national and global scales ( Figure 5). There was no significant difference among the responding groups as to whether or not they perceived the same 10 threats as major threats to national and world fisheries (G = 10.191, df = 9, p = 0.335), where G is the likelihood-ratio, df the degree of freedom and p the probability value.
Overfishing was believed to be a major threat to world fisheries by 79% of the managers, 92% of the policy-makers, 79% of the scientists and 84% of the fishers ( Figure 5). Notably, 69% of the policymakers and scientists said they believe that illegal, unreported and unregulated (IUU) fishing is not a major threat to national fisheries, while 78% of the fishers said they think it is.
Fifty-eight percent of all respondents believed climate change to be a major threat to national fisheries, while 59% believed that ocean acidification is a major threat to world fisheries and 40% to national fisheries. Seventy-two percent of the fishers said they think habitat destruction is a major threat to the marine environment for world fisheries, while only 13% said it is a threat to national fisheries. Forty-one percent of the scientists believed land-based pollution is a major threat to fisheries, compared to 84% of the fishers, 85% of the policy-makers and 79% of the managers. Of all the respondents, 46% said plastic is a major threat to world fisheries (57% of managers and 62% of the scientists) and 30% said it is a major threat to national fisheries. Despite the divergence in views in the earlier question pertaining to whether IUU is a threat to international or national fisheries, there was no significant difference among the responding groups on how they viewed the specific aspects of IUU fishing (G = 61.275, df = 45, p = 0.054). Corruption was seen as the main aspect of IUU fishing (66%), with 55% of respondents believing that there is insufficient compliance in place to combat IUU fishing ( Figure 6). Sixty-four percent said they believe IUU fishing is a problem within their fishery, and of those 43% said they think IUU fishing amounts to 6-30% of the total catch (Appendix A). When specifically asked about IUU (rather than ranking it against other threats), on a global scale, 99% of the respondents believed that IUU fishing is a problem and 65% estimated the global level of IUU fishing to be between 31-60% of the total catch worldwide (Appendix A).

Fisheries Governance and Management Affecting Fisheries and Marine Systems
On the question of what the three main challenges to fisheries are, the following four factors ranked the highest: a lack of political will (56%); not enough compliance with regulations (33%); overfishing (29%); and stock assessment and monitoring (28%) (Figure 7). There was no significant difference among the responding groups regarding which of the four factors were seen as the main challenges to managing fisheries (G = 23.409, df = 15, p = 0.076). Despite compliance being listed as a major challenge to sustainability, 90% of the fishers and 66% of the scientists said there is already enough compliance. Fifty-five percent of the respondents believed that, during the course of their careers, they have seen major changes in fisheries management, such as increased input from scientists and industry, and stakeholder collaboration ( Figure 8). Four main challenges to managing fisheries More of the respondents were satisfied than dissatisfied with the planning and implementation of the EBFM processes. However, when considering the results of EBFM, a greater number of respondents were neutral, out numbering those who were satisfied or dissatisfied ( Figure 9). When looking to the fisheries they knew best, 60% of the respondents said that the fishery they worked with has implemented (EBFM) (Appendix A), or a similar holistic approach to governing fisheries, though 50% said they were unsure as to whether the implementation of EBFM has been successful ( Figure  10).

EBFM process satisfaction
Planning process Implementation process Results Figure 10. The perception of those respondents who said the EBFM process has been implemented regarding how successful the process had been (n = 107).
There was no significant difference among the responding groups in terms of their satisfaction with the planning processes associated with implementing EBFM (G = 11.358, df = 10, p = 0.33), with 73% of the managers, 67% of the policy-makers, 47% of the scientists and 50% of the fishers being satisfied. Thirty-eight percent of the scientists and 50% of the fishers were neutral. When it came to taking the step of implementing EBFM, there was also no significant differences among the responding groups on how they felt regarding this implementation process (G = 21.174, df = 15, p = 0.131), with approximately 50% of both the scientists and fishers being neutral.
Sixty-four percent of the managers and 58% of the policy-makers were satisfied with the results of implementing EBFM, compared with 31% of the scientists, 46% of the fishers and 0% of the NGOs (Table 1). About as many scientists as managers thought the implementation process of EBFM had been unsuccessful (Table 1) and about as many fishers as scientists remained neutral as to whether the EBFM implementation process had been successful (Table 1). Once EBFM is in place (often in an adaptive management context), it is important to know if it is proving successful. When asked about this, there was no significant difference among the responding groups regarding how satisfied they were with the results of EBFM (G = 16.571, df = 10, p = 0.084): 55% of the managers were satisfied, compared with 23% of the scientists ( Table 2). Of the fishers, 65% were neutral and 67% of the NGOs were dissatisfied ( Table 2). Figure 11 shows that EBFM is challenging to implement, mainly because the process is highly complex.
There was a significant difference among the responding groups regarding which tools are most efficient for implementing EBFM (G = 44.226, df = 20, p = 0.001). Respondents viewed good science, Marine Protected Areas (MPAs), individual transferable quotas (ITQs), gear restrictions and stakeholder participation to be the five most efficient tools for Ecosystem-Based Fisheries Management ( Figure 12).

Improvements Needed to Obtain and Maintain Sustainable Fisheries
For the question on what type of organisation would be optimal for implementing EBFM, 83% believed that a mix of a top-down and bottom-up management is optimal (Appendix A). When it came to what more is needed to sustain fisheries, 72% of all respondents answered they believe a stronger political will is needed to achieve successful ecosystem-based management ( Figure 13).

Five most efficient tools for implementing EBFM
There was no significant difference among the responding groups regarding which improvements are needed to sustain fisheries (G = 5.747, df = 20, p = 0.999), with all groups identifying the same mix of factors. However, this congruence did hide some differences in detail. Amongst managers, a clear majority (79%) stated that stronger political will is needed. A majority of managers (60%) also said they think more enforcement is needed; this latter result is in sharp contrast to the 25% of fishers who felt the same way. Overall, 53% of the respondents believed that more science is needed in order to obtain and maintain sustainable fisheries ( Figure 13). The majority of the respondents were supportive of input controls, such as by-catch reduction devices, size limits, spawning and spatial closures, regional zoning, seasonal closures and gear restrictions ( Figure 14). The majority of the respondents also showed support for output controls, such as total allowable catch (86%), individual transferable catch (69%) and bag limits (69%) (Appendix A).

Support of input controls
When it came to monitoring and assessing stocks, Catch Per Unit Effort (CPUE) was the most common method used for measuring fish abundance ( Figure 15), although logbook data was considered a close second. Experts were asked to identify what they see as the main challenges to sustainable fisheries and what management tools would be generally useful for combatting challenges in fisheries (Table 3). Interestingly, while the challenges included things that are beyond the scope of fisheries management alone (e.g., land-based pollution or plastics), all of the suggested tools are classical fisheries management tools. When asked the question regarding why regulated fisheries are still faced with overexploitation, the highest ranking responses were: (1) the need for more scientific information; (2) existing science not being used to its fullest; and (3) a lack of political will. There was no significant difference to these three reasons among the responding groups (G = 2.001, df = 10, p = 0.996). The vast majority of all responding groups (regardless of background) said that the lack of political will is a major reason why regulated fisheries are still faced with overexploitation (Table 4). Table 3. Ten main challenges and ten main tools for sustaining fisheries (n = 133).  Lack of political will 93% 92% 74% 84% 80%

Socioeconomic Situations Affecting Fisheries and Marine Systems
Forty-two percent of the respondents said fish as a protein source is not important for survival in their country, 7% said it was, and 23% considered fish vital for some regions (Appendix A). However, when questioned on how important fishing is as a main source of income, 65% of the respondents said fishing is the major economic activity for a few regions, 42% said fishing is a vital source of income for some regions and 37% said that fishing is somewhat important as a main source of income for the country as a whole (Appendix A). Regarding subsides, 52% of the respondents said that fisheries subsidies are available in their country, 34% said there are no subsidies and 14% did not know (Appendix A). Of those who said there are subsidies in their country, 88% said they have fuel subsidies, 35% have employment subsidies, 26% have lower interest rates on bank loans and 15% said they have subsidies related to culture. Sixty-five percent of the respondents believed that subsidies contribute to overcapacity of the fishing industry ( Figure 16). There was particular support amongst the respondents for economic incentives, such as fishing access agreements and fishing vessel buy-backs by the government (Figure 17).

Not at all 32%
Somewhat 40% Significantly 25% Don't know 3% Fifty-one percent of the respondents were not able to estimate the cost of management for the fishery they work with (Appendix A).

Discussion
Results from the survey demonstrate that the respondents have had extensive experience in the fisheries management process, including both science and management. The respondents had formal qualifications and/or experience; with 42% having Doctoral degrees, 28% Masters degrees and almost half of the respondents having senior or executive roles in fisheries. The coverage was also global, representing 34 nations in total. While we acknowledge the sample sizes were uneven, with more scientists answering than any of the other respondents, there was congruence in many results, suggesting that perceptions held by fisheries scientists and managers may not actually be that different. Indeed, in many cases, fishers also held similar attitudes, though there were some notable differences (e.g., on the need for additional enforcement). In following up on why it proves so hard to access the opinions of managers, let alone policy-makers (who were an even smaller respondent group), it became clear that they lack opportunities to gather and share information in the same way as provided by scientific conferences. Funding such travel is often hard to do. In improving the state of fisheries globally-sharing insights into what has and has not worked-it appears that there is a fundamental need for the creation of a fora, or a conduit, for information sharing amongst these managerial and policy groups.

Threats and Challenges in Sustaining Fisheries
This analysis clearly confirmed that sustaining fisheries is a complex challenge, but the experts also offered their opinions as to how to combat the issues involved, which are generally consistent with the literature on how to sustainably manage fisheries [37][38][39][40]. The respondents considered the 10 main threats to fisheries to be overfishing, climate change, habitat destruction, pollution, ecosystem shifts, IUU fishing, ocean acidification, costal development, land-based pollution and introduced species. These same threats were considered important at national and global scales. This shows that the threats and challenges to sustaining fisheries are similar around the world; a finding consistent with existing scientific literature [8,[41][42][43].

Support
Neutral Oppose

Management Tools in Sustaining Fisheries
Although the analysis highlights an extensive range of challenges in achieving sustainable fisheries, it also shows that the respondents believe there are many existing tools for addressing these obstacles and supporting sustainable fishing. Just as the main challenges and threats to sustaining fisheries were viewed similarly around the world, so too the list of potential tools was consistent across respondents from differing backgrounds and nationalities. While overfishing was seen as a major threat to sustaining fisheries (nationally and globally), the majority of all responding groups said it is not a challenge to manage. Given concern over the magnitude of the problems facing "small scale" fisheries and the difficulties of achieving successful management in locations with few regulatory resources [44], this is a surprising response. However, this may be because the respondents primarily work in fisheries with a range of regulations in place, with compliance and enforcement mechanisms already implemented to combat this challenge and so they have directly experienced the management of overfishing. This result may highlight a tacit bias in the workpeople working in less well-resourced fisheries are unlikely to have had the means to visit the Congress where the survey was undertaken-and future follow-up on this work should endeavour to address this gap.
Tools identified as useful in sustaining fisheries included sound science, input controls (gear restrictions, seasonal closures, spatial closures, spawning closures, by-catch reduction device, size limits and regional zoning), output controls (bag limits, ITQs, Total Catch Limits (TACs)), a mixture of top-down and bottom-up organisation, stakeholder participation, fishing access agreements and fishing vessels buy-backs, effectively taking an integrated or ecosystem approach. In particular, the vast majority of all responding groups viewed good science, MPAs, ITQs, gear restrictions and stakeholder participation to be the five most efficient tools for Ecosystem-Based Fisheries Management. All of these tools are consistent with what have been recorded as good supporting tools for sustainable fisheries in other research [39,[45][46][47].
More of the respondents were satisfied than dissatisfied with the EBFM's planning and implementation processes. More were, however, neutral regarding the results of the EBFM, reflecting in part the complex nature of the EBFM process. Management tools might be put in place, but it may take a long time before any results are seen. These approaches may be introduced when the system has been overfished and shifted to a state where restoration may take a lengthy period [48][49][50]. More managers than any other responding group said they believed the EBFM implementation process was a success. About the same number of managers, policy-makers and scientists said they believed it was unsuccessful. Possibly, there were different expectations among the various responding groups, where the managers saw it as a success in itself that such a large management process had been adopted and implemented by the government in the first place; while the scientists may have been more cautious (neutral) because any biological success was yet to be seen. More managers and policy-makers said they were satisfied with the results of EBFM than the scientists and fishers, although all responding groups showed a cautious element to any success, the fishers more so than any other group. Again, the expectations are likely to differ among the various stakeholders, as implementing EBFM unavoidably involves trade-offs in meeting all biological, economic and social goals [51], which will differ between the different groups.
Given the growing focus on the implications of a high level of marine pollution [52][53][54], it might be surprising that only just over half of the respondents answered that they believe land-based pollution is a major threat to the world's fisheries and 46% said plastic is a major threat. This might be due to the fact that the survey was undertaken in 2012 when there was not as much scientific reporting on plastics in the ocean [55]. It was particularly noteworthy though that, despite pollution and plastics being identified as threats, few, if any, of the suggested tools put forward are likely to have a significant role in combating these issues. This indicates that, while awareness of the issue is growing, focus is still on the classical threats and long-established tools.

Management Constraints in Using More Science
Fisheries management in the majority of industrialised nations is said to be science or evidencebased, even if science-based advice is not always followed in the political process [56]. This analysis showed 'not using scientific knowledge to its fullest potential' to be the main constraint for effectively and efficiently implementing ecosystem-based fisheries management, together with: (1) a lack of compliance; (2) IUU still being a major global issue; and (3) political will.
The management of marine systems in general, and fisheries in particular, is highly complex and a story of information paucity. It is very difficult to estimate even the abundance of target species. In some regions, it is even difficult to precisely determine what has been extracted from the ocean, let alone the effects on dependent species or species not directly impacted by fishing [57]. The reason why science is not being used to its fullest is interesting. Is it because of a disconnect of science and management? In Australia, having fisheries scientists work closely with but ultimately sit apart from the management agency has been a successful approach, as the participatory processes in place there allow for communication, while the 'distance' has helped increase trust in science and motivation of scientists by all stakeholders. In other regions, the organisational disconnect has led to barriers to information uptake. In these latter instances, because scientists belong to a separate organisation, they are treated more as a consultant and thereby not fully integrated in the management process, leading to critical communication failures. An example of this is where scientists from the International Council for the Exploration of the Sea (ICES) advise the Oslo Paris Commission (OSPAR), the Helsinki Commission, the Baltic Marine Environment Protection Commission (HELCOM), the North East Atlantic Fisheries Commission (NEAFC), the North Atlantic Salmon Conservation Organization (NASCO) and the European Commission (EC) [58]. Yet, despite all of these channels, the decisions have still been largely political, leading to overfishing within the European Union [59][60][61][62]. More recently, there have been significant efforts to reverse this, though it has only been patchily effective; the Mediterranean, in particular, still has a majority of its stocks in an overfished state [63].
An alternative example is found with the Commission for the Conservation for Antarctic Marine Living Resources (CCAMLR). CCAMLR has its scientific committee with its working groups fully integrated in the organisation advising the commission at the annual meetings. Many participants are a part of both the scientific commission and the commission [64][65][66][67]. This science-based commitment to ecosystem-based management has, since 1982 (when CCAMLR was founded), contributed to the recovery of previous overfished stocks, and sustainable management of the Southern ocean ecosystems, including fisheries [39,68,69].

A Brief Comment on Cognitive Inconsistencies
With the growing accessibility of literature regarding human cognition, it would be remiss of us not to note how the perceptions reported in this survey may be effected by common cognitive biases and fallacies [70,71]. We are not trained professionals in the field of psychology, so will not go into depth, but the results for IUU appear to be a stand out example of such biases in action. There is clear recognition that IUU is a problem, with almost complete consensus on this point across respondents. However, it appears that the perception of the magnitude of the problem is strongly influenced by an optimism bias (with far fewer respondents thinking it is a problem in their own fishery) and by biases to do with framing (it is seen as more of an issue when asked directly about IUU rather than in general bundled with other risks) and uncertainty (as the true magnitude of the problem is typically unknown and so may be discounted as a result). In addition, the fact that the suggested solutions for sustainable fisheries include a list of existing tools, many of which have been in use in fisheries for centuries, suggest that there may be a strong endowment effect, with experts sticking strongly to tools they are already heavily invested in without necessarily looking for new alternatives. This is worth additional research to verify. If confirmed, it would open up new research paths; if falsified, then it would reassure all stakeholders that we already have at hand all the tools we need to achieve sustainable fisheries.

Political Will to Match Biological Challenges
The survey showed that, despite implementation of EBFM and increased levels of input from science, industry and NGOs, sustaining fisheries remains a challenge. The main challenge when managing fisheries was said to be a lack of political will. We note that policy-makers represented just 7% of the respondents, and the issue of sustaining fisheries due to a lack of political will might have been viewed differently had there been more policy people participating in the survey. Indeed, knowledge brokers who span the science-policy interface caution that policy-makers can become frustrated with scientists who fail to appreciate the many sources of information and many pressures that must be navigated by policy-makers when making a single decision [72]. Political advisers and politicians must also consider political, social, cultural and economic matters.
The challenge to managing fisheries ranked second by the respondents was a shortage in compliance and regulations, stock assessments and monitoring. This might not come as a surprise as there are high costs involved for scientific assessments and controlling regulations [73]. In linking the top two challenges, the challenge found regarding the lack of compliance may reflect a lack of general political and social will to fund and implement required management controls [70]. Politicians may be more inclined to act on issues more important to the voters (who have concerns extending well beyond fisheries), and perhaps, at times, they do not either fully appreciate the seriousness of the marine issues or the need for long-term sustainable plans that span many election cycles.
However, what might not be high on the political agenda today may change with building public awareness, which in turn may demand better management of natural resources [71]. The United Nations' Ocean Conference for implementation of Sustainable Development Goal 14 ('Conserve and sustainably use the oceans, seas and marine resources for the sustainable development') is an example. This conference was held in June 2017, with 193 nations making a commitment to a set of measures aiming to increase the resilience of ocean health. These pledges have been accompanied by over 1400 voluntary commitments. Together, these commitments can be seen as a global commitment (raised from increased scientific and public pressure) for politicians to better manage marine life. Given increased consciousness of environmental issues among the public since this survey was conducted [72,73], it would be interesting to conduct a similar survey today to see if there is a perception of a stronger political will today to sustain fisheries.

Conclusions
This study reinforces the magnitude of the challenges in sustaining fisheries. It identified key issues underpinning the use of an ecosystem management approach, such as complexity, the high degree of connectivity, difficulties associated with observing ocean processes and monitoring flora and fauna. The fact that 99% of the respondents believed that IUU fishing still is a global problem and 65% estimated the global level of IUU fishing to be between 31 and 60% of the total catch worldwide is, naturally, a major concern. Tools identified as useful in sustaining fisheries included sound science, gear restrictions, seasonal closures, spatial closures, spawning closures, by-catch reduction device, size limits and regional zoning, bag limits, ITQs and TACs. The study indicated that the common position of the respondents is that the use of a mixture of top-down and bottom-up organisation and institutional forms is important to success, as is the importance of stakeholder participation. However, implementing these solutions will come with new challenges, especially when implementing them at scales aligning with the magnitude of participation in "small-scale" (often poorly resourced) fisheries in developing nations. The survey also highlighted the impact of fishing access agreements and fishing vessels buy-backs as tools to constrain effort. Again, these are things that may work more effectively for industrial than some artisanal fisheries.
This research illustrated a clear perception of a need for a higher political will and commitment to combat challenges, such as IUU fishing, habitat destruction and climate change, both nationally and globally. More research and long-term monitoring to assist managers in prioritization resources was also identified as a particularly important need. It was clear from the analysis that the widely held belief by those experts in charge of the world's fisheries that, to recover from overfishing and fisheries collapse (and to minimise the future risk of such events), scientific input must be matched with the same level of political commitment, including implementing science-based fisheries and conservation measures.
It is also worth noting that human cognition is not infallible. When asked directly about illegal, unreported and unregulated fishing, 99% of the respondents saw it as a global issue; however, when put against other challenges, close to 70% of the policy-makers and scientists believed that is not a major threat to national fisheries, despite the fact that almost 80% of the fishers said they think it is. This suggests that there is a gap in the discourse and management of IUU fishing that likely needs closer consideration or discussion.
This analysis showed that there is the strong perception that scientific knowledge is not being used to its fullest potential and that in turn is the main constraint for effectively and efficiently implementing ecosystem-based fisheries management. Is the challenge then a lack of political will only, or is this a reflection of the make-up of respondents: scientists frustrated with a perceived lack of political appreciation? Perhaps there is a greater need to establish science-management networks that meet regularly, to train a new generation of scientists who have direct industry and regulatory body experience (spending time in both as well as academia before completing their training), as well as a need for scientists to communicate science in a more pedagogical way?

Conflicts of Interest:
The authors declare no conflict of interest.

Appendix A
Fisheries Governance Survey, with responses Q1. Threats to the marine environment: For each of the potential marine threats, please tell if you believe there is no threat, a minor threat or a major threat.