Growing fisheries have intensively exploited fish stocks since the 1950s, leading to global overfishing and to worldwide resource depletions (Pauly et al., 2002, 2005; Watson et al., 2013). This has severely impacted the economies and societies of maritime countries around the world, particularly in the coastal countries of the developing world (Pauly et al., 2005; Béné, 2006; Swartz et al., 2010). In many of these countries, small-scale fisheries are particularly suffering from competition with industrial fisheries (Allison, 2001). Given the importance of these fisheries in providing food security and livelihoods to numerous coastal communities (Pauly and Zeller, 2014; Golden et al., 2016), proper management is required.

The Food and Agriculture Organization of the United Nations (FAO) has been reporting “official” fisheries catches by country since 1950. In many countries, this is the only available information on marine living resources (Froese et al., 2012; Pauly and Zeller, 2016). Given that most methods to assess the status of fish stocks require substantial and costly data (e.g., fisheries independent surveys etc.), fisheries catch data remain, in many cases, the only basis for fisheries management (Worm et al., 2009; Costello et al., 2012; Pauly et al., 2013). Despite the importance of these data (Pauly et al., 2013), fisheries catch data reported by countries to the FAO are often heavily focused on commercial sectors only. FAO data requests specifically exclude discards, while data for most small-scale sectors (i.e., artisanal, subsistence and recreational) are often missing or substantially under-represented (Pauly and Zeller, 2016). The fact that global FAO data do not even differentiate between large- and small-scale catches (Pauly and Charles, 2015) makes proper evaluations of sectoral importance and affiliated management actions even harder to derive (Pauly and Zeller, 2016).

By (re-)evaluating official and unofficial marine fisheries components, the catch reconstruction approach (Zeller et al., 2007, 2015) can provide a more comprehensive, and likely realistic picture of what is being withdrawn from world oceans. These components involve catches from the large-scale (industrial) and small-scale (artisanal, subsistence, and recreational) sectors, plus major discards (Pauly and Zeller, 2016). These catch estimates may be approximate, and with higher uncertainty than reported data, but they are better than assigning a value of zero catch to unmonitored fishing sectors (Pauly and Zeller, 2016).

This study aims to provide a better estimation of the Sultanate of Oman's domestic marine fisheries catches that can be used to improve fisheries management in the country. Oman is an Arab country situated in the south east of the Arabian Peninsula, with a land area of around 300,000 km², a continental shelf area of 54,000 km² and an Exclusive Economic Zone (EEZ) of 536,000 km² (www.seaaroundus.org; Figure 1). Because of its separation from the rest of the Arabian Peninsula by the Rub al Khali, i.e., the largest sand desert in the world, Oman's main connections with the rest of the world were via the ocean (Metz, 1993; Vincent, 2008). Musandam, one of Oman's governorates, is an exclave surrounded by the United Arab Emirates (Figure 1B). This governorate itself contains an exclave in the UAE, called Madha (75 km²), which amazingly contains an even smaller exclave of the UAE, called Nahwah.

Before the discovery of oil in 1962, the economy of Oman was based mainly on agriculture and fisheries, which represented 70% of the GPD (Metz, 1993). Until the mid-1980s, the economy of the country experienced a rapid expansion, with the oil industry accounting for 59% of GDP in 1985 (Metz, 1993). A drop in oil prices slowed down this expansion between 1986 and 1989, but prices increased again in the 1990s (Metz, 1993). During the pre-oil period, and due to relatively abundant fisheries resources (Strømme, 1986), the fishing sector was the second largest contributor to the economy, after farming (Riphenburg, 1998). However, with the expansion of the oil industry, fishers started leaving their boats for a more remunerative activity (Metz, 1993). Thus, in the early 1970s, the Omani government started developing and organizing the fishing sector by establishing the Fisheries Department followed by the creation of the Ministry of Agriculture and Fisheries, or MAF (Alhabsi et al., 2011); in 1978, it started subsidizing the fisheries, via a “Fishermen's Encouragement Fund” to increase employment in the fishing industry (Metz, 1993; FAO, 2001). During the 1990s, the Omani government decided to invest even more in potentially sustainable sectors, and thus funded several fisheries development and research projects, e.g., the Oman Fisheries Development and Management Project (Metz, 1993). In 2007, the Ministry of Fisheries Wealth was formed (Alhabsi et al., 2011). Until the 1980s, the Omani fishing industry was only small-scale in nature. In the 1980s, an industrial fishery was launched, following the signing of fishing agreements between Oman and other countries. In 1989, Oman ratified the UN Convention on the Law of the Sea (Morgan, 2006).

“Catches” are defined as the sum of “landings” (i.e., retained and landed catch) plus “discarded” catch. Available data for total landings are assembled by taxon and year, for the period 1950-2015. Although, the national Omani fishery data and the reported FAO data for Oman have an overall similar trend, the taxonomic disaggregation in the national reports is more detailed. Therefore, national data are used as the baseline for the years 1985-2015 and data from the FAO's Fishstat database are used for the years 1950-1984, as data from Oman were unavailable. To this baseline dataset, we added estimates of previously unreported commercial large- and small-scale, recreational, and subsistence landings, as well as major discards, as obtained from independent and government studies, as well as the gray literature; throughout, we followed the general catch reconstruction approach outlined in Zeller et al. (2007, 2015). Catches were reconstructed for the whole country, then for the Musandam Governorate separately. Estimates of the catches of the sectors mentioned were then obtained for the rest of the country by subtraction. A taxonomic disaggregation is then performed for both spatial datasets, i.e., Musandam and the rest of Oman.

Overall, total reconstructed domestic marine fisheries catches in the whole of Oman (i.e., Musandam plus the rest of the country, Figure 4; Appendix 5) increased from around 64,000 t·year⁻¹ in the early 1950s (~48,000 t·year⁻¹ reported in the 1950s according to FAO data) to around 92,000 t·year⁻¹ in the 1960s (71,000 t·year⁻¹ reported according to FAO data). During the 1970s to the 1990s, catches reached respectively around 127,000, 144,000, and 156,000 t·year⁻¹. During the past 15 years, total marine fisheries catches more than doubled, increasing from around 142,000 t in 2000 to almost 290,000 t in 2015. Overall, the reconstructed total catch is 1.2 times the landings reported by the FAO on behalf of Oman for the period 1950-2015.

Reconstructed total catches for the main part of Oman (excluding Musandam) are dominated by the artisanal sector, i.e., 90% of total catches are artisanal (Figure 2A; Appendix 1). Around 20% of the total artisanal catches are unreported. The industrial fishery rapidly gained importance in the 1990s, reaching a peak of 28% of total catches in 1997. Due to the ban on trawlers, by 2015, this fishery became almost non-existent (i.e., 0.08% of total catches, with only one active longliner). Subsistence and recreational catches are estimated to be 1% and < 0.01% of total catches, respectively. Discards contributed around 1.2% of the total catch.

The main fish families caught by fishers in the main part of Oman, Figure 2B; Appendix 2, are the Clupeidae (~32%), which consist mostly of Indian oil sardine (Sardinella longiceps), followed by mackerels (Scombridae, ~19%), emperors (Lethrinidae, ~6%), jacks (Carangidae, 4.6%), and groupers (Serranidae, ~3.6%).

Catches of separate area Musandam represented 3% of the reconstructed total catch for Oman. Reconstructed marine fisheries catches in Musandam consist of 98% small-scale catches, of which about 12% are unreported (Figure 3A; Appendix 3). Subsistence and recreational catches represent a negligible fraction of marine catches, i.e., ~0.7% and < 0.01%, respectively. Discards represent around 1% of the catch in Musandam. As illustrated by Figure 3B; Appendix 4, Scombridae are the most important taxonomic group (~38%), followed by anchovies (Engraulidae,~15%), and Carangidae (~14%). Lethrinidae, Clupeidae, and Serranidae make up around 4% each of total marine fisheries catches in Musansdam.

The marine fisheries catch reconstruction for Oman for the period 1950-2015 combines the reported large- and small-scale commercial landings with our best estimates of unreported large- and small-scale commercial, recreational, and subsistence catches, as well as estimates of large- and small-scale discards. Some of these estimates are very uncertain (Table 5, Figure 4), but they likely represent, overall, a more accurate picture of the total catch than if these components were omitted (which is the unavoidable result of not reporting on existing, but unmonitored components).

Small-scale fisheries are very important in Oman, i.e., nearly 98% of total catches in 2015 are artisanal in nature. The industrial fishery, composed of trawlers and longliners, has been decreasing in importance over the past decade. For several reasons, including conflicts between artisanal and industrial fishers, the Omani authorities have banned trawling since 2011 (Fisheries Statistic Department of Oman, 2012; Alhabsi, 2013). Even before this measure, the Omani government invested greatly in controlling the activities of the industrial fishing sector through quotas, gears, temporal and fishing areas restrictions, the prohibition of discarding and the deployment of on-board governmental observers (Morgan, 2006). Since the 1970s, the fishing industry has been heavily subsidized and several initiatives were taken to improve fishery management, product quality and fisheries research (Morgan, 2006; Alhabsi et al., 2011). This includes the production of annual fisheries statistical reports that are much more detailed than those of neighboring countries (Fisheries Statistic Department of Oman, 2010, 2012, 2016).

Nevertheless, the catch reconstruction for Oman shows that almost 20% of total marine fisheries catches, including discards are unreported. This result is based mostly on conservative assumptions, and thus may be higher. While it may be argued that 20% is low, especially compared with neighboring countries (Al-Abdulrazzak and Pauly, 2013), there is still a need for local studies to estimate the real incidence of the different unreported fishing activities in Omani waters.

Recreational fishing has been growing exponentially in Oman, in parallel with the rapid development of the tourism sector in general¹, i.e., number of arrivals increased by almost 50% between 2011 and 2014. A simple online search using key words such as “fishing in Oman” leads to numerous websites and online platforms that give very detailed fishing guides to foreign recreational fishers in Oman², e.g., providing information on the best seasons, species, area, and gears for “a good fishing experience.” For instance, annual and daily licenses for sport fishing provided by the Omani authorities increased by a factor of 3 in the 2010-2015 time period, increasing from just over 1% of total fishing licenses in 2010 (including professional licenses) to 3% in 2015 (Fisheries Statistic Department of Oman, 2011, 2016). Recreational fishing is currently so common that conflicts between professional and recreational fishers are starting to emerge³. Subsistence fishing, although not as important as in the pre-oil period, still plays a role in the Omani society. Fishing has always been culturally and traditionally part of the lives of the Omani people. According to Maynard (1988), “the Omani coastal populations are traditional sea-faring people with the basic skills for a working life at sea.” Although, this might not be currently as prevalent as previously, Belwal et al. (2015) pointed out that families of fishers practice fishing without a license and that subsistence fishing does exist.

Unreported artisanal catches are likely to be considerably higher than the findings of this study. Several commercial artisanal fisheries are not being monitored or even considered to be fisheries. The tribal, independent nature of coastal communities of fishers across Oman is what characterizes the traditional small-scale Omani fishery. Yet, this very same nature, combined with the large number of artisanal fishers, is what makes the management and the monitoring of the artisanal commercial fishery challenging for the Omani government (Al-Marshudi and Kotagama, 2006; Morgan, 2006; Qatan, 2010). Instead of adapting to the nature of its traditional fishery, the Omani government appears to have decided, perhaps based on its experience with the industrial fishery, to use a centralized top-down fisheries management approach, while allowing open access to poorly regulated artisanal fisheries (Morgan, 2006; Alhabsi, 2013). This is likely to lead to overcapacity problems in the future.

As for the commercialization of catches, even when fishers are licensed, they do not necessarily sell their catches through the regulated channeled markets, and their catches are thus not monitored by the fisheries catch data collection system (Morgan, 2006), e.g., selling fish directly to consumers on the road, without passing through the fish markets⁴. One non-monitored small-scale commercial fishery is particularly interesting: the invertebrate fishery by Omani fisherwomen. These women have been part of the small-scale fishing industry in Oman for a long time, and mainly collect gastropods and bivalves from beaches as a source of income (Rashdi and McLean, 2014). Such under-valued and often ignored fisheries contributions by women are widespread around the world (Harper et al., 2013).

Despite the efforts of the Omani government in limiting and even prohibiting discarding, this practice is likely to occur occasionally (Kwiatkowska et al., 2000; Morgan, 2006), as fishing operations need to be tightly monitored to suppress discarding entirely. Note that the FAO explicitly requires countries not to include discards as part of their annual fisheries catch reports (Pauly and Zeller, 2016).

Oman is the first Arab state to ratify the 2009 FAO Port State Measures Agreement. Yet, illegal fishing has been occurring in the Omani EEZ. For instance, there used to be an export of spiny lobster and fish to other countries that is not reflected by the data recording system (Morgan, 2006). Several foreign countries used to fish in Omani waters and their catches have not been reported or monitored, e.g., Thailand used to fish on the coast of Oman during the 1970s (Pauly, 1996). In this catch reconstruction, this illegal fishing was not accounted for because of the scarcity of information. However, this warrants further historical research.

A tentative stock assessment was performed for the Narrow-barred Spanish mackerel, known in Oman as Kingfish, (Scomberomorus commerson, McIlwain et al., 2005), but scarcity of data precludes other major exploited species from being assessed (Fouda et al., 2009). What little is known is consistent with the observation that “fishing down” occurs in Omani waters (Abd-El-Rahman, 2014), e.g., in Dhofar and Albatinah. As well, by comparing the reported artisanal marine fisheries catches of each province, we noticed that marine catches in the north (Musandam) and in the south (Sharqiyah, Dhofar, and Wusta) are increasing, while catches in the center (Muscat and Batinah) are decreasing (Figure 5). This may be a consequence of stronger declines in the central area, where major urban centers occur.

Compared with the cost of traditional stock assessments, catch-based indicators would represent a cheaper and less data-demanding method to assess the status of fisheries in Oman (Pauly et al., 2013). Such indicators, however, require accurate catch data, i.e., including the landings from all fisheries sectors, and their discards, if any.

This study illustrates the need for continuously improving the data monitoring system for Oman, with emphasis on all fishing sectors and components. This cannot be done without the improvement of its fisheries related infrastructure such that it can address the need of rural coastal communities of artisanal and subsistence fishers, and also requires methods to be developed and applied for estimating recreational catches. Oman aims to rely on its marine living resources when its oil is depleted. It will be able to do this only if it ensures that its fish stocks do not meet the same fate as its oil, and sound management starts with best possible data.

MK: Completed the data assembly and analysis, and drafted the article; KZ: Assisted in general catch reconstruction queries, and edited the manuscript; DZ: Advised on methodological approaches, guided analytical decisions, and contributed to the manuscript; DP: Guided the conceptualization of the study, reviewed and edited the manuscript, and presented the findings to the government of Oman.