Status of resources
Based on FAO’s assessment,13 the fraction of fishery stocks within biologically sustainable levels decreased to 64.6 percent in 2019, that is 1.2 percent lower than in 2017 (Figure 23). This fraction was 90 percent in 1974. In contrast, the percentage of stocks fished at biologically unsustainable levels has been increasing since the late 1970s, from 10 percent in 1974 to 35.4 percent in 2019. This calculation treats all fishery stocks equally regardless of their abundance and catch. Biologically sustainable stocks account for 82.5 percent of the 2019 landings of assessed stocks monitored by FAO.
FIGURE 23GLOBAL TRENDS IN THE STATE OF THE WORLD’S MARINE FISHERY STOCKS, 1974–2019
Biologically sustainable stocks consist of the maximally sustainably fished and underfished stocks, accounting for, respectively, 57.3 percent and 7.2 percent of the total number of assessed stocks in 2019. The underfished stocks maintained a decreasing trend over the entire period (bouncing back slightly during 2018 and 2019), whereas the maximally sustainably fished stocks fell between 1974 and 1989, to then increase, reaching 57.3 percent in 2019. In 2019, among FAO’s 16 Major Fishing Areas, the Southeast Pacific (Area 87) had the highest percentage (66.7 percent) of stocks fished at unsustainable levels, followed by the Mediterranean and Black Sea (Area 37) 63.4 percent (Figure 24). In contrast, the Northeast Pacific (Area 67), Eastern Central Pacific (Area 77), Western Central Pacific (Area 71) and Southwest Pacific (Area 81) had the lowest proportion (13–23 percent) of stocks fished at biologically unsustainable levels. Other areas varied between 27 percent and 45 percent in 2019 (Figure 24). Landings of fish varied greatly among fishing areas (Figure 9b), and therefore, the significance of each area for global fishery sustainability may vary depending on its proportionate contribution to the global landings The temporal pattern of an area’s landings often reveals information about its ecological productivity, fishery development stage, management and fishery stock status. In general, after excluding Arctic and Antarctic areas, which have minor landings, three groups of patterns can be observed (Figure 25): (i) areas with an overall declining landing trend following historical peaks; (ii) areas with catches oscillating around a globally stable value since 1990, associated with the dominance of pelagic, short-lived species; and (iii) areas with a continuously increasing trend in catches since 1950. The first group has the lowest percentage of biologically sustainable stocks (59.2 percent), the second group the highest (76.1 percent), while the third is in between (67.0 percent). When management intervention is not strong, an increasing trend of catch (the third group) suggests development of fishing and lack of control, with resource sustainability most likely in good shape. However, when there is an increasing trend, stock assessment may involve great uncertainty and be unreliable due to the lack of contrast resulting from the one-way-trip pattern in catch or catch per unit of effort. In contrast, a decreasing trend in catch (the first group) usually suggests worsening sustainability of fishery stocks or implementation of strict regulations but lack of recovery. The highest level of sustainability (the second group) is likely to be associated with the full development of fisheries, mature management and effective regulation in fishing. However, other issues, such as environmental changes and social factors, can also influence catch trends. Box 3 illustrates the FAO plan to revise the current assessment methodology to better reflect the major changes that have occurred in the relative dominance of different fisheries resources.
FIGURE 24PERCENTAGES OF BIOLOGICALLY SUSTAINABLE AND UNSUSTAINABLE FISHERY STOCKS BY FAO MAJOR FISHING AREA, 2019
BOX 3IMPROVING THE FAO PERIODIC ASSESSMENT OF THE STATE OF WORLD FISHERY RESOURCES
Since its first publication of the global review of marine fishery stocks in 1971,1 FAO has been regularly assessing and monitoring the state of world marine fishery resources with results published biennially in The State of World Fisheries and Aquaculture (SOFIA) since 1995. The objective of the FAO assessment is to provide an overview of the global and regional state of marine fishery resources to help with policy formulation and decision-making for the long-term sustainability of these resources. As marine fisheries have developed, both the assessment methods and the relative data available have undergone significant change. The current methodology was revised in 20112 and has not been updated since. In order to continue providing a comprehensive and objective global analysis, FAO has decided to revise the methodology to better reflect the major changes that have occurred in the relative dominance of different fisheries resources, and to base the analysis on an updated and more comprehensive list of fishery stocks. The new methodology will update the list of stocks and provide a tiered and transparent approach to a new analysis with newer reporting formats. These changes are also expected to engage more directly with the growing community of assessment and management institutions and experts in Member Countries, and thus enhance transparency.
The revised plan to address these issues in future reports on the state of world marine capture fisheries is to adopt a regional strategy, where gaps in assessment can be narrowed over time by using a tiered approach linked to the level of information available. The initial and most important step is to update the list of stocks considered in the analysis in each region, thus better reflecting current realities in fisheries in different parts of the world. This will be done collaboratively with local experts, through regional workshops and new forms of consultations, such as the Sustainable Development Goal (SDG) Indicator 14.4.1 (Proportion of fish stocks within biologically sustainable levels) country-specific questionnaires. The tiered assessment approach depends on the quality of the data and supplementary information for each region:
- Tier 1 – Stocks for which traditional stock assessments are available and deemed reliable. Formal results are used as reported by the management agencies.
- Tier 2 – Stocks for which no formal assessments are available, but for whom alternative approaches (such as Sraplus3) are viable, because supplementary information, such as external data on landings with abundance indices or expert-driven priors for depletion, is available to derive a state of the particular stock.
- Tier 3 – If data are insufficient for either Tier 1 or Tier 2 approaches, then a weight-of-evidence4 approach to categorize the status of the stock based on qualitative/semi-quantitative information will be used.5
To demonstrate the proof of concept of this tiered approach in a transparent SOFIA assessment framework, two FAO statistical areas (Area 31 and Area 37) will be piloted by FAO to present to the Thirty-fifth Session of the Committee of Fisheries (COFI) in 2022, comparing the current and new approach in terms of derived metrics. The pilot will document the data, workflow, analysis and reporting in a standardized format that is easily replicable. In addition, new infographics (see figure for a preliminary prototype example) will be developed to provide a more engaging communication format and present fisheries assessments in a wider context aligned with the ecosystem approach to fisheries management (EAFM).6
A detailed work programme to achieve the objectives of modernizing the SOFIA indicator on the status of marine resources will be proposed to the Thirty-fifth Session of COFI. If endorsed, examples of the tiered analysis and new visual communication approaches will be offered in the 2024 edition of The State of World Fisheries and Aquaculture with a full roll-out in most areas. A new edition of the FAO Technical Paper, Review of the state of world marine fishery resources, will subsequently be published describing the methodology in detail. The work programme also envisions a process to increase the capacity of national and regional fisheries institutions for assessing the state of the stocks. The programme will encourage greater participation and more active involvement in the global analysis by national institutions, empowering them to regularly present their analyses as inputs to the FAO flagship publication in conjunction with reporting on progress on SDG Indicator 14.4.1.
- 1 Gulland, J.A. 1971. The fish resources of the ocean. West Byfleet, UK, Fishing News Books. www.fao.org/3/al937e/al937e.pdf
- 2 FAO. 2011. Review of the state of world marine fishery resources. FAO Fisheries and Aquaculture Technical Paper No. 569. Rome.www.fao.org/3/i2389e/i2389e.pdf
- 3 Stock reduction analysis + (Sraplus) includes options to estimate depletion based on external covariates.
- 4 The weight-of-evidence approach was initially developed by the Australian Government:
Woodhams, J., Stobutzki, I., Vieira, S., Curtotti, R. & Begg, G.A., eds. 2011. Fishery status reports 2010: status of fish stocks and fisheries managed by the Australian Government. Canberra, Australian Bureau of Agricultural and Resource Economics and Sciences.
The approach aims to hypothesize alternative stock status based on different indicators (social, biological or economic). The weight of evidence would indicate the highest probability of a status using multiple approaches indicating the most likely outcome.
- 5 Castro de Souza, M. & Barros, P. forthcoming. Providing EAF-compliant management advice in data- and capacity-limited fisheries: A framework using the weight of evidence approach. Rome, FAO.
- 6 Staples, D., Brainard, R.,Capezzuoli, S., Funge-Smith, S., Grose, C., Heenan, A., Hermes, R. et al. 2014. Essential EAFM. Ecosystem approach to fisheries management Training Course. Volume 2 – For Trainers. RAP Publication 2014/13. Bangkok, FAO Regional Office for Asia and Pacific, Bangkok, Thailand.www.fao.org/3/i3779e/i3779e.pdf
DRAFT INFOGRAPHICS ON REGIONAL INFORMATION IN THE CONTEXT OF MULTIPLE INDICATORS RELEVANT TO FISHERIES MANAGEMENT AND ECOSYSTEM COMPLEXITY
Status and trends by major species
For the top ten species with the largest landings in 2019 – anchoveta (Peruvian anchovy) (Engraulis ringens), Alaska pollock (walleye pollock) (Gadus chalcogrammus), skipjack tuna (Katsuwonus pelamis), Atlantic herring (Clupea harengus), yellowfin tuna (Thunnus albacares), blue whiting (Micromesistius poutassou), European pilchard (Sardina pilchardus), Pacific chub mackerel (Scomber japonicus), Atlantic cod (Gadus morhua) and largehead hairtail (Trichiurus lepturus) – on average, 66.7 percent of these stocks were fished within biologically sustainable levels in 2019, slightly higher than the global average of 64.4 percent. European pilchard, Atlantic cod and Atlantic herring had higher than average proportions of overfished stocks.
Tuna stocks are of upmost importance because of their large volume of catches, high economic value and extensive international trade. Moreover, their management is subject to additional challenges owing to their highly migratory and often straddling distributions. At the global level, the seven species of tunas of principal commercial importance are albacore (Thunnus alalunga), bigeye tuna (Thunnus obesus), skipjack tuna (Katsuwonus pelamis), yellowfin tuna (Thunnus albacares) and three species of bluefin tuna (Thunnus thynnus, Thunnus maccoyii, Thunnus orientalis). The main commercial tunas contributed 5.7 million tonnes of catch in 2019, a 15 percent increase from 2017 but still 14 percent lower than the historical peak in 2014. On average, of the principal commercial tuna species, 66.7 percent of stocks were fished within biologically sustainable levels in 2019, slightly higher than the all-species average, but unchanged in comparison with 2017.
Tuna stocks are closely monitored and extensively assessed, and the status of the seven above-mentioned tuna species is known with moderate uncertainty. However, other tuna and tuna-like species remain mostly unassessed or assessed under high uncertainty. This represents a major challenge, as tuna and tuna-like species are estimated to account for at least 15 percent of the total global small-scale fisheries catch (FAO, Duke University and WorldFish, forthcoming). Furthermore, market demand for tuna remains high, and tuna fishing fleets continue to have significant overcapacity. Effective management, including better reporting and access to data and the implementation of harvest control rules across all tuna stocks, is needed to maintain stocks at a sustainable level and in particular rebuild overexploited stocks. Moreover, substantial additional efforts on data collection, reporting and assessment for tuna and tuna-like species other than the main commercial species are required.
Status and trends by fishing area
The Northwest Pacific has the highest production among the FAO Major Fishing Areas, producing 24.1 percent of global landings in 2019. Its total catch fluctuated between 17 million tonnes and 24 million tonnes in the 1980s and 1990s and was about 19.4 million tonnes in 2019 (Figure 25). Historically, Japanese pilchard (Sardinops melanostictus) and Alaska pollock used to be the most productive species, with peak landings at 5.4 million tonnes and 5.1 million tonnes, respectively. However, their catches have declined significantly in the last 25 years. In contrast, landings of squids, cuttlefishes, octopuses and shrimps have increased greatly since 1990. In 2019, two stocks of Japanese anchovy (Engraulis japonicus) were overfished, while for Alaska pollock two stocks were overfished and another sustainably fished. Overall, in 2019, about 55.0 percent of assessed stocks were fished within biologically sustainable levels, and 45.0 percent fished outside these levels, in the Northwest Pacific, a 10 percent increase compared with the last assessment in 2017.
FIGURE 25THE THREE TEMPORAL PATTERNS IN FISHERIES LANDINGS, 1950–2019
In recent decades, catches in the Eastern Central Pacific have oscillated between 1.5 million tonnes and 2.0 million tonnes (Figure 25). Total landings in 2019 were 1.9 million tonnes, close to the maximum seen in history. A large proportion of the landings in this area are small and medium-sized pelagic fish (including important stocks of California pilchard (Sardinops sagax), anchovy and Pacific jack mackerel (Scomber japonicas), squids and prawns. The productivity of these stocks of short-lived species are naturally more susceptible to interannual variations in oceanographic conditions, which generate oscillations in catches despite sustainable exploitation rates. Catches of California pilchard in the Gulf of California stock have for instance recovered dramatically in the last three years, most likely in response to favourable environmental conditions. As noted in previous years, overfishing impacts selected coastal resources of high value, such as groupers, snappers and shrimps. However, the status of these stocks is considered highly uncertain due to the limited information available. The percentage of assessed stocks in the Eastern Central Pacific fished within biologically sustainable levels has remained stable since 2015 at 85.7 percent, the second highest among fishing areas.
The Southeast Pacific produced 7.8 million tonnes of aquatic animals in 2019, accounting for about 10 percent of global landings, with a clear decreasing trend since the 1990s (Figure 25). The two most productive species were anchoveta and jumbo flying squid (Dosidicus gigas), with landings of almost 5.0 million tonnes and 0.9 million tonnes, respectively. These species are considered to be within biologically sustainable levels, mostly due to a decrease in landings since the early 1990s as part of a more precautionary and effective fisheries management of anchoveta. Araucarian herring (Strangomera bentincki) was also harvested within sustainable levels. In contrast, South American pilchard (Sardinops sagax), South Pacific hake (Merluccius gayi) and Southern hake (Merluccius australis) continued to be overfished, and Patagonian toothfish (Dissostichus eleginoides) is currently being fished at unsustainable levels. Although the majority of the catch (approximately 95 percent) within this region comes from stocks at sustainable levels, overall, just 33.3 percent of the assessed stocks in the Pacific Southeast were fished within sustainable levels in 2019.
The Eastern Central Atlantic has seen an overall increasing trend in catches, but with fluctuations since the mid-1970s, reaching 5.4 million tonnes in 2019, the highest value in the time series (Figure 25). European sardine is the single most important species, with reported catches of about 1 million tonnes per year since 2014 and its stocks remain underfished. Round sardinella (Sardinella aurita) is another important small pelagic species. Its catches have been generally decreasing to about 184 000 tonnes in 2019, only about 50 percent of its peak value in 2001. The species is considered overfished. The demersal resources are known to be intensely fished in the region, and the status of the stocks varies – some are classified as sustainable and others as unsustainable. Overall, 60 percent of the assessed stocks in the Eastern Central Atlantic were within biologically sustainable levels in 2019.
In the Southwest Atlantic, total catches have varied between 1.8 million tonnes and 2.6 million tonnes (after an early period of increase that ended in the mid-1980s), reaching 1.7 million tonnes in 2019, a 5 percent decrease from 2017 (Figure 25). The species with the largest landings is the Argentine shortfin squid (Illex argentinus), representing 10–30 percent of the region’s total catches historically. However, landings of this species decreased to 250 000 tonnes (14 percent) in 2019, and in contrast, Argentine red shrimp (Pleoticus muelleri) catch has grown significantly since 2005. Both were fished within biologically sustainable levels. In 2019, Argentine hake (Merluccius hubbsi) catch increased by 26 percent from 2017 and thus represents the most important species in terms of catch volumes for the region with 449 000 tonnes. One of the hake stocks had recovered to biologically sustainable levels in 2019 as a result of significant efforts to improve assessment and management, including reductions in fishing mortality. Moreover, Patagonian grenadier (Macruronus magellanicus) and whitemouth croaker (Micropogonias furnieri) have shown an increase in catches of about 70 percent and 20 percent, respectively, since 2017. Overall, 60.0 percent of the assessed stocks in the Southwest Atlantic were fished within biologically sustainable levels in 2019, a 20 percent improvement from 2017.
In 2019, landings in the Northeast Pacific remained at the same level as 2013, at about 3.2 million tonnes (Figure 25). Alaska pollock remains the most abundant species, representing about 50 percent of total landings. Pacific cod (Gadus microcephalus), hakes and soles are also large contributors to the catches. Most species except salmon stocks in this region are healthy and well managed, primarily due to the science-based advice from the North Pacific Fisheries Commission and North Pacific Fishery Management Council and to good governance that has helped reduce fishing pressure from distant water fishing nations. However, stocks of Pacific salmon (chinook, coho, sockeye and chum in southern parts of British Columbia in Canada, and the states of Washington, Oregon and California in the United States of America) were overfished in 2019. Overall, 86.2 percent of the assessed stocks in the area were fished within biologically sustainable levels in 2019, the highest among fishing areas.
The Northeast Atlantic is the third most productive area and had a catch of 8.1 million tonnes in 2019, a decline of 1.2 million tonnes from 2017. Its landings reached a peak of 13 million tonnes in 1976, then dropped, recovered slightly in the 1990s and have been decreasing since (Figure 25). Its fishery resources experienced extreme fishing pressures in the late 1970s and early 1980s. Since then, countries have managed better fishing pressure to rebuild overfished stocks. Recovery was seen in Atlantic mackerel (Scomber scombrus), turbot (Scophthalmus maximus), European plaice (Pleuronectes platessa), common sole (Solea solea), Arctic cod (Boreogadus saida) and Atlantic cod (Gadus morhua) in the 2000s, and common sole (Solea solea) and whiting (Merlangius merlangus) in the late 2010s. In the Northeast Atlantic, 72.7 percent of the assessed stocks were fished within biologically sustainable levels in 2019.
The Northwest Atlantic produced 1.7 million tonnes of aquatic animals in 2019 and continued a decreasing trend from its peak of 4.5 million tonnes in the early 1970s (Figure 25). The group of Atlantic cod, silver hake (Merluccius bilinearis), white hake (Urophycis tenuis) and haddock (Melanogrammus aeglefinus) has not shown a good recovery, with landings remaining at about 0.1 million tonnes since the late 1990s, only 5 percent of their historical peak value of 2.1 million tonnes in 1965. The reasons behind the poor recovery are environment-driven changes in productivity for some stocks, such as Atlantic cod (Gadus morhua), American plaice (Hippoglossoides platessoides), winter flounder (Pseudopleuronectes americanus) and yellowtail flounder (Limanda ferruginea). Although catches may be very low and overfishing is not occurring, these stocks have still not recovered. In general, invertebrate fisheries are in a better state than finfish fisheries. Overall, 61.1 percent of the assessed stocks in the Northwest Atlantic were fished within biologically sustainable levels in 2019.
Total catches in the Western Central Atlantic reached a maximum of 2.5 million tonnes in 1984, then declined gradually to 1.2 million tonnes in 2014, and rebounded slightly to 1.4 million tonnes in 2019 (Figure 25). Small pelagic fishes, namely Gulf menhaden (Brevoortia patronus) and round sardinella are considered to be fully fished. Medium-sized pelagic fishes such as king mackerel (Scomberomorus cavalla) and Atlantic Spanish mackerel (Scomberomorus maculatus) appear to be fully fished, while the serra Spanish mackerel (Scomberomorus brasiliensis) appears to be overfished. Snappers and groupers are among the most highly valued and intensively fished in the region and, despite reductions in directed fishing effort thanks to management actions, some stocks continue to be overfished. Highly valued invertebrate species such as Caribbean spiny lobster (Panulirus argus) and queen conch (Lobatus gigas) are considered fully fished. Penaeid shrimps are currently sustainably fished, as well as the Atlantic seabob (Xiphopenaeus kroyeri) along the Guianas-Brazil shelf. In the Western Central Atlantic, 62.2 percent of the assessed stocks were fished within biologically sustainable levels in 2019.
The Southeast Atlantic has shown a decreasing trend in landings since the late 1960s, from a total of 3.3 million tonnes to 1.4 million tonnes in 2019 (Figure 25). Horse mackerel and hake support the largest fisheries of the region and have recovered to biologically sustainable levels following good recruitment and strict management measures. The Southern African pilchard (Sardinops ocellatus) stocks are still very degraded, warranting special conservation measures from both Namibia and South Africa. The sardinella (Sardinella aurita and Sardinella maderensis) stocks, very important off Angola and partially in Namibia, remained at biologically sustainable levels. Whitehead’s round herring (Etrumeus whiteheadi) was underfished. However, Cunene horse mackerel (Trachurus trecae) remained overfished in 2019, and perlemoen abalone (Haliotis midae), targeted heavily by illegal fishing, continued to deteriorate and remained overfished. Overall, 64.7 percent of the assessed stocks in the Southeast Atlantic were fished within biologically sustainable levels in 2019.
After reaching a historical maximum of about 2 million tonnes in the mid-1980s, total landings in the Mediterranean and Black Sea declined to a low of 1.1 million tonnes in 2014; since 2015, they have recovered slightly, with a catch of 1.4 million tonnes in 2019 (Figure 25). Most of the commercially important stocks regularly assessed continue to be fished outside biologically sustainable limits, including the stocks of hake (Merluccius merluccius), turbot (Scophthalmus maximus) and European pilchard. A decreasing trend in the level of overfishing of some of these stocks has been observed in past years but according to the General Fisheries Commission for the Mediterranean (GFCM), the overall fishing mortality for all resources combined is estimated at nearly 2.5 times higher than sustainable reference points. In 2019, 36.7 percent of the assessed stocks in the Mediterranean and Black Sea were fished within biologically sustainable levels.14
The Western Central Pacific produced the second largest landings, 13.9 million tonnes (17 percent of the global total) in 2019, continuing the linear increasing trend since 1950 (Figure 25). Aquatic species are highly diversified, but catches are not always split by species, often recorded as “miscellaneous coastal fishes”, “miscellaneous pelagic fishes” and “marine fishes not identified”, which together constituted almost 50 percent of the region’s total landings in 2019. Major species are tuna and tuna-like species, contributing about 21 percent of total landings. Sardinellas and anchovies are also significant in the region. Few stocks are considered to be underfished, particularly in the western part of the South China Sea. The high reported catches have probably been maintained through expansion of fishing to new areas or through fishing down trophic levels of targeted species. The tropical and subtropical characteristics of this region and the limited data availability make stock assessment challenging with great uncertainties. Overall, 79.6 percent of the assessed fishery stocks in the Western Central Pacific were fished within biologically sustainable levels in 2019.
The Eastern Indian Ocean continues to show a steady increase in catches, with 6.8 million tonnes in 2019 (Figure 25). Stock status information is generally scarce and available only for a few coastal stocks in certain areas. Most of the stocks monitored by FAO are assessed based on catch trends and other ancillary information rather than analytical stock assessments or fishery independent data. Therefore, the state of stocks in the region is considered highly uncertain and should be treated with caution. Toli shad (Tenualosa toil), sardinellas (Sardinella spp.), Indian mackerel (Rastrelliger kanagurta) and Indian oil sardine (Sardinella longiceps) have highly fluctuating landings, most likely driven by the combined effect of fishing pressure and changing environment. Hilsa shad (Tenualosa ilisha) stocks are either fully fished or overexploited. Among the stocks considered within sustainable levels are anchovies, banana prawn, giant tiger prawn, squids and cuttlefish. Of the assessed stocks in the Eastern Indian Ocean, 65.3 percent were fished within biologically sustainable levels in 2019.
In the Western Indian Ocean, total landings continued to increase and reached 5.5 million tonnes in 2019 (Figure 25). Main Penaeidae shrimp stocks fished in the South West Indian Ocean, a main source of export revenue, continue to show clear signs of overfishing, prompting the countries concerned to introduce more stringent management measures. The stocks of sea cucumber across the region are considered overexploited. The Southwest Indian Ocean Fisheries Commission continues to update the assessment of the status of the main fished stocks in the region. The 2019 assessment estimated that 62.5 percent of the assessed stocks in the Western Indian Ocean were fished within biologically sustainable levels, while 37.5 percent were at biologically unsustainable levels.
Prospects of achieving the SDG target on fisheries
In 2019, 64.6 percent of the fishery stocks of the world’s marine fisheries were fished within biologically sustainable levels. The significant continuous decreasing trend over time (Figure 25) is cause for alarm in the international community and among all relevant stakeholders, as urgent concrete plans and efforts are needed to achieve sustainable fisheries.
Overfishing – stock abundance fished to below the level that can produce maximum sustainable yield (MSY) – not only causes negative impacts on biodiversity and ecosystem functioning, but also reduces fisheries production, which subsequently leads to negative social and economic consequences. Rebuilding overfished stocks to the biomass that enables them to deliver MSY could increase fisheries production by 16.5 million tonnes and annual rent by USD 32 billion (Ye et al., 2013). It would also increase the contribution of marine fisheries to the food security, nutrition, economies and well-being of coastal communities. The situation seems more critical for some highly migratory, straddling and other fisheries resources that are fished solely or partially in the high seas. The United Nations Fish Stocks Agreement (in force since 2001) should be used as the legal basis for management measures of the high seas fisheries.
The United Nations Sustainable Development Goals (SDGs) set a clear target on fisheries (SDG Target 14.4): to end overfishing of marine fisheries by 2020. The world fisheries are now diverging away from this target. However, this global picture may mask regional and intra-country differences in progress. A recent study (Hilborn et al., 2020) shows that scientifically assessed and intensively managed stocks have, on average, seen abundance increasing or at proposed target levels and that in contrast, regions with less developed fisheries management have much greater harvest rates and lower abundance than assessed stocks. This highlights the urgent need to replicate and re-adapt successful policies and regulations in fisheries that are not managed sustainably and to create innovative mechanisms that promote sustainable use and conservation around the world.
The productivity and resilience of inland water ecosystems is primarily driven by environmental factors, the most important of which include temperature, water flows and nutrient pulses driven by the seasonal expansion and contraction of aquatic systems. The species of these ecosystems have life strategies that allow them to take advantage of the inherent variability or stability of different systems depending on the location, whether they are arctic, montane, temperate or tropical, lakes, rivers, wetlands or floodplains.
The performance of fishery stocks or specific inland fisheries is intimately related to water quality and quantity and to the size and health of the habitats on which they rely to complete their life cycles and the connectivity between these. In tropical floodplains, which are home to some of the world’s largest inland fisheries, and on which large numbers of people depend for their livelihoods, food security and nutrition, inter-annual variability in flooding decides survival and growth rates of the aquatic species and thus the size of the stocks capable of recovering from high levels of mortality. Fishing pressure in these systems can be significant but is not normally the principal driving factor that determines the status of the fisheries. Conversely, isolated stocks in temperate or Arctic lakes or streams may be very vulnerable to overfishing, although impacts on habitat, spawning grounds and connectivity may still be important or even overriding factors in determining the health of the stock.
The significant inland fisheries of the world’s tropical basins may be further characterized by the large number of species present and the highly diversified fisheries which exploit them. As many of these important food fisheries lie within least developed or low-income food-deficit countries, there are limited human and financial resources to monitor and manage such fisheries. Given the highly dispersed nature of many of these fisheries, the use of traditional assessment methods (length frequency surveys, catch and effort surveys, fishery independent surveys, etc.) is time-consuming and expensive and hard to justify considering the limited options for deriving revenue from the landings and the low return on investment to the State. Even in some developed countries, the low profile of inland waters means that assessment and monitoring may be a relatively low priority or seen as an unwarranted expense when there are so many other competing needs.
The transboundary nature of catchments and river basins is another challenge to overcome, as basin boundaries do not necessarily follow convenient country borders, or those of their subnational jurisdictions. Few major river basins with important inland fisheries lie completely within the borders of a single country. In large continental and archipelagic countries, the national inland fishery landings are provided by the catch from several different basins, all driven by their own local pressures. In neither of these situations will an aggregate national catch figure provide an accurate or satisfactory or informative indicator of the status of the inland fisheries of a country. Importantly, the tendency in many countries is to monitor only the largest fisheries or landing sites and apply estimations or ignore other less intensive fisheries, further obscuring the understanding of the true state of inland waters and their fisheries.
Just how should we try to track the status of inland fisheries in these contexts, as part of our commitments to achieving the targets of SDG 1 (No poverty), SDG 2 (Zero hunger), indirectly SDG 14 (Life below water) and SDG 15 (Life on land) to inland waters?
Without proper assessments, the impacts on inland fisheries for food and biodiversity caused by water development, agricultural and industrial environmental impacts, deforestation and land degradation go unaccounted for.
It has been recognized for some time that these limitations in national assessments and the basin nature of inland fisheries require a new assessment paradigm that can combine information from multiple sources, often collected remotely and using proxy measurements, but the tools and computer modelling power to do this have not been available. Starting in 2016, FAO initiated a process in collaboration with the United States Geological Survey (USGS) and selected fishery experts to develop a global threat map for inland fisheries that combined 20 identified anthropogenic pressures acting across catchments and basins to create a composite threat indicator. The relevant pressures on each basin and sub-basin that affect inland fisheries were weighted according to their importance in each basin. The initial results of this model were presented in the 2020 edition of The State of World Fisheries and Aquaculture (FAO, 2020a) with the intention of providing an update in the 2022 edition.
The threat assessment method has now been further refined by USGS and automates boosted regression model outputs from over 150 spatial data layers across the threat categories which affect inland fisheries. This was achieved by improving the weighting approach to make the spatial data meaningful and assign relative importance values. The approach combines weights from literature, boosted regression trees and expert opinions. More than 9 000 peer-reviewed articles on documented threats, responses and impacts from 45 basins most important to inland fisheries catch were reviewed. The results were complemented with a survey among 536 inland fisheries professionals from 79 countries with expertise on 93 basins, who were asked to apply threat scores at the local level to the fisheries with which they were most familiar. The threat assessment represents a fully transparent, reproducible framework that will permit an objective assessment of inland fisheries with a high level of confidence. An accompanying web portal will summarize assessment outcomes for fishery managers and other users.
Figure 26 summarizes threats by continent according to aggregated pressure categories. Criteria for pressure categories were evaluated on a numeric scale of one to ten, where “low pressure” was considered those with a score of 1–3, “moderate pressure” a score of 4–7 and “high pressure” a score of 8–10. Across all major basins important to inland fisheries, 28 percent of fisheries are estimated under low pressure, 55 percent under moderate pressure, and 17 percent under high pressure (left bar, “World”). Most regions follow a similar pattern of proportional distributions. These results call attention to the majority of basins with intermediate to high levels of degraded ecological attributes and can be used to improve inland fisheries by providing a baseline metric to track changes. There are several important considerations for these estimations. One is that in this figure each basin is represented equal to the other basins rather than relative across basins by size or fisheries catch. For example, basins that cover large geographic areas (e.g. Congo) are represented equal to those of small areas (e.g. Sepik). However, because the model can use data at different scales, basin and hydrological characteristics may be used to aggregate threats differently according to the metrics most relevant to fishery managers or users. It is also essential to note that in this figure, the number of basins vary across continents. For example, Asia and Africa have, respectively, 12 and 14 hydrological basins important to inland fisheries, while Oceania only has 2. To increase ease of use and interpretation, results from the assessment will be summarized across biogeographical realms, ecoregions and hydrological basins.
FIGURE 26STATE OF MAJOR INLAND FISHERIES BY REGION
Analysis of individual basins
The threat mapping approach permits an evaluation of threats to inland fishery food production and biodiversity at different levels of resolution from the global level to the level of individual basins or sub-basins. The sub-basin disaggregation shows how different parts of a basin may contribute to its overall threat level and may show that not all parts of a basin are affected in the same way, and thus reveal where to focus conservation and ecosystem restoration efforts, and each part of the basin may support different fisheries and be subject to different threats. The vulnerability of the fisheries and their socio-economic characteristics will also vary according to their spatial distribution and will need to be considered. Linking an understanding of the state of the selected inland fisheries to the global threat map would also provide a baseline and a means to report meaningfully on progress on inland fishery stocks towards international goals such as the Aichi Targets, and support to the SDGs through recognition of the importance of inland fisheries to food security in some countries and subnational areas and how action on ecosystem restoration can sustain this. To develop a regular yet meaningful global assessment of inland fisheries will require commitment and additional resources to undertake assessments of the indicator fisheries on a routine basis and agreement to report into a common framework. This would enable FAO to collate a global assessment in a similar manner to that of the FAO marine stock status assessment.
The advantage of this approach is that it uses global, publicly available data, thus allowing coverage of countries that may have very limited capacity to collect and report data to FAO; by selecting a number of indicator basins in each region, it will be possible to gain insight into the state of the fisheries in different parts of the world. However, for calibration and improved interpretation, the findings should be “ground-truthed” using locally available data, local knowledge and, where possible, collection of complementary data in the field; this is especially the case for large complex basins with several different fisheries in operation. Linking the threat maps to fishery data at a subnational level will enable more detailed national analysis and planning, especially pointing to areas where there is a need for greater understanding of primary threats and their relationship to fisheries production and biodiversity of aquatic species. This would enable national fishery agencies to identify important inland fisheries (or aquatic biodiversity) that are at risk and prioritize appropriate fishery monitoring and management interventions. Where there are several different fisheries operating in the same body of water that respond differently to the drivers or respond to different drivers (this could, for example, be fisheries for large predatory species and small pelagic fish taking place in the same water body or fishing for floodplain resident and migratory species in a major river), the outcomes require careful interpretation as different groups of stakeholders may be affected in different ways.
An additional step in developing a more detailed report could involve the selection and systematic tracking of a number of indicator fisheries in some of the most productive basins. Each of these fisheries would convey important information about what is happening in the basin of concern – information that may be translated into meaningful management actions. The data could also be reported into a common framework that would allow FAO to further refine the global-level assessment. Box 4 is an illustration of how such a basin assessment could be presented.
BOX 4EXAMPLE OF A BASIN ASSESSMENT: LAKE MALAWI/NIASSA/NYASA
Figure A explores how a basin assessment could be done using the example of Lake Malawi/Niassa/Nyasa, one of the great East African rift lakes shared between Malawi, Mozambique and the United Republic of Tanzania. Population density and growth rate are high, especially in the Malawian part of the basin. Fishing is one of the most important sources of livelihood and at least 1.6 million people are dependent on it. Fish is an essential source of animal protein, providing 70 percent of animal protein in Malawi. The fisheries can be divided into semi-industrial (12 percent of landings), using 32 pair and 8 stern trawlers, and artisanal (88 percent of landings), using mostly dugout canoes. Common gear types include gillnets, open water seines with lamps as attraction lights, traps and mosquito nets. Malawi began systematic monitoring in their waters of semi-industrial fishery in 1976 and of artisanal fishery in 2002. There are no comparable datasets for the other two countries.
FIGURE A Lake Malawi/Niassa/Nyasa basin report card
The trawl fishery of Lake Malawi/Niassa/Nyasa has been in decline since around 1990, while the landings in the artisanal fishery have grown since data collection started, mostly as a result of a larger number of fishers and higher fishing effort. There have been major shifts in the composition of the catches (Figure B). The artisanal fishery used to be rather diversified, but the lake Malawi sardine (Engraulicypris sardella) now contributes more than 90 percent of the artisanal catch, although with large interannual fluctuations. The trawl fishery mostly targets a number of cichlid species, of which the Chambo (Oreochromis spp.) collapsed in the early 1990s and never recovered, while the Chisawasawa (Lethrinops spp., demersal deep-water cichlids) has been in decline since the mid-2000s. Currently the trawl fishery mainly catches Ndunduma (Diplotaxodon spp., deep-water pelagic cichlids), for which there is limited competition with the artisanal fishery, and the catches remain fairly stable. Overfishing is generally believed to be responsible for the changes in fish catch composition observed. However, other factors including water abstraction, pollution, land-use change and climate change are most likely contributing factors. As in other lakes, fish production in Lake Malawi/Niassa/Nyasa is driven by nutrients originating from natural and anthropogenic sources in the basin’s tributary rivers. In addition, there is recirculation of nutrients from the bottom layers due to upwelling. Upwelling varies according to the strength and direction of the prevailing winds, and the depth of the thermocline, which is determined by water temperature. The response to variations in nutrient inputs is typically immediately visible in small pelagic zooplanktivorous species such as the lake Malawi sardine.
FIGURE B Fish landings in the artisanal and semi-industrial fisheries in Lake MALAWI/NIASSA/NYASA
While information at the species level may not be essential, the number of species present in the catches contains an important message. Nevertheless, it is important to monitor different ecological guilds (e.g. migratory species, small pelagics, large-growing and long-living species, non-native species). These indicator fisheries are most likely directed at important species that are already monitored; however, this is not an actual requirement, provided the catches supply information about the status of all the species in the guild.
- 13For the methodology for the assessment, see FAO Fisheries and Aquaculture Technical Paper No. 569 (FAO, 2011a).
- 14With the main aim to support fisheries management, the GFCM provides a regional assessment of the status of priority commercial stocks in the Mediterranean and Black Sea. This assessment is based on analytical scientific assessments of management units (a combination of priority species and geographical subareas of interest) covering about 50 percent of the catches. The assessment also indicates that in 2018, a high proportion (75 percent) of priority commercial stocks assessed were considered outside sustainable fishing levels, in line with the results presented in the 2020 edition of The State of World Fisheries and Aquaculture, but also suggests that this percentage has decreased by about 10 percent since 2014 (FAO, 2020).