The abalone Haliotis mariae (locally called As’sufailah) is endemic to the subtropical Arabian Sea coast of southern Oman, where it inhabits inter- and subtidal rocky substrates down to 20 m depth (Bosch and Bosch, 1982; Johnson et al., 1992). In this habitat, abalone shelter among rocks and in crevices during daytime and forage nocturnally. Larger individuals occur in deeper areas than smaller animals (Anon, 1984). The life cycle of H. mariae is related to the southwest monsoon driven upwelling that occurs from June to August (Johnson et al., 1992), which decreases seawater temperature and increases nutrient concentrations (Barratt et al., 1986). During the premonsoon (March-May) and monsoon period, the brown and red algae on which H. mariae predominantly feed are scarce or absent (Barratt et al., 1984; Jupp, 2002). In the post-monsoon months of September to February, abalone move into shallower waters to reproduce and feed (Al-Hafidh, 2006). Females appear to spawn once a year with a peak spawning during December and January, and a gradual decrease during February and March as algae become scarce (Al-Hafidh, 2006). Sea urchins appear to be a competitor for food (Tripneutes gratilla) and living space (Diadema spp.), and natural predators on abalone include scalloped spiny lobster (Panulirus homarus), seastars (Asterias spp.), octopus (Octopus aegina), cuttlefish (Sepia spp.) and finfishes like morays (Gymnothorax spp.). A fishery for H. mariae is concentrated around Sadah, with catches declining towards Sharbithat in the East and Mirbat to the West . The annual production of abalone from a two-month fishing season was estimated at 50 t in 2006, valued at more than US$ 8 million (MAF, 2007).
Economically, it has the highest yield per kg of all Omani fisheries products. Intense fishing by locals using free diving methods have led to sharp decline in catches, and abalone stock is presently regarded as overfished (Al-Hafidh, 2006). The aquaculture of abalone on a commercial scale has developed rapidly in several countries including the USA, Mexico, South Africa, Australia, New Zealand, Japan, China, Taiwan, Ireland and Iceland (Hahn, 1989; Gordon and Cook, 2001). Specific culture techniques need to be developed or adapted for each abalone species. The geography and subtropical climate of Oman with warm clean coastal waters lends itself to aquaculture, and H. mariae furthermore has a unique yellow foot and excellent meat texture. Given the high value of abalone products on international markets and the decline of wild stocks, the aquaculture of H. mariae in Oman was investigated in a series of projects since 1994, the resources of which are available in several internal- and unpublished reports (Ogawa, 1994, 1997; Iwao, 2000; Al-Rashdi, 2001; Endo, 2005), but have not appeared in the peerreviewed literature. (Al-Rashdi and Iwao, 2008).
The Omani abalone (Haliotis mariae) is a prevalent species distributed along the southern coast of Oman. They are considered as one of the premium seafood delicacies in Oman and have the highest commercial value among all Omani fisheries products (Balkhair et al. 2013). Historically, the Omani abalone was traded to other regions including Yemen and India, and more recently China. During the last few decades, the Omani abalone stock has been seriously overexploited because of concentrated fishing; illegal harvest by fishing out of the permitted season; the harvest of small, immature specimens, and a fishery practice of overturning boulders and thus destroying the abalone habitat (Al-Hafidh 2006). Recently, it was apparent that the Omani abalone populations could not be maintained under the sustained fishing pressures. Therefore, research on biological and technological methods for the seed production of H. mariae has been undertaken with emphasis on spawning induction and larval rearing development and latterly restocking of hatchery-bred seeds of Omani abalone to the natural habitat has been implemented. Although the mass production of Omani abalone is currently successful, there are still many issues associated with the percentage of survival rates that need to be resolved.( Balkhair et al., 2016)
Commercial abalone farming in Oman
The abalone fishing industry in southern Oman – an important source of livelihood for traditional fishing communities distributed along the coast of Dhofar Governorate – is set for a big boost with an anticipated uptick in the commercial farming of this hugely coveted seafood delicacy.
The first of two abalone farming projects initiated last year in the Governorate is due to produce its maiden harvest this year. Oman Aquaculture Company, set up by Al Jazeera Investments at a cost of around RO 5.7 million, will celebrate this year the harvest of its first crop of ‘Golden Abalone’ (Haliotis Mariae) from its newly established farm in Mirbat.
The Mirbat project represents a successful effort to commercially produce Golden Abalone, a high-value locally occurring species that is billed as one of the highest quality and most valuable species of abalone in the world. Together with a similar venture under development at Sharbathat (Wilayat of Shaleem al Al Halaniyat Islands), the projects are aimed at sustaining the farming of Omani abalone for local consumption and export as well.
For centuries, Omani fishermen and women have been harvesting naturally occurring abalone at key locations off the Dhofar coast. Equipped with locally fashioned wetsuits, but without the benefit of breathing apparatus, they have mastered the art of diving in shallow waters and scouring the seafloor for these shelled gastropods, which are found clinging to rocks. In recent decades, abalone fishing has been restricted to a brief season during winter to help conserve and sustain the industry.
But given the soaring demand for abalone, particularly in markets in the Far East, international and local investors have explored the potential for commercial farming of the lucrative seafood. Assisting the interested parties in the expeditious processing of approvals and permits for their investments has been Implementation Support & Follow-up Unit (ISFU) of the Diwan of Royal Court, a high-powered committee tasked with fast-tracking projects and initiatives aimed at accelerating Oman’s economic diversification.
Besides facilitating approvals for the 200-tons per annum capacity Mirbat farm, ISFU has also rendered similar assistance to Al Jazeera Investments in the delivery of the Sharbathat abalone farm. Construction work on the RO 5.6 million farm project is due to be wrapped up shortly. At full capacity, it will produce around 450 tons of farmed abalone per year. Separately, the parent company is also setting up a hatchery and 50-ton-capacity grow-out farm for abalone broodstock at Al Lakbi on Oman’s Wusta coast. (Oman Observer, 2020)
Cephalopod fishery comprising cuttlefish, squid and octopus, in the Oman coastal waters is economically very important, due to the high commercial value in national and international markets. In the past, the cuttlefish was caught as bycatch and didn’t have any commercial value. In 90’s, increasing attention was paid to this valuable fishery and of late it has become a target species for both artisanal and industrial fisheries in Oman. Cuttlefish constitutes about 16% of the demersals’ total catch (Annual fishery statistics book, 2011) earning about 11 million Omani Rial (OR ≈ 2.6$). The major species of cuttlefish in the Omani waters are Sepia pharaonis and Sepia prashadi. Sepia pharaonis (Ehrenberg, 1831) is distributed in Indo-Pacific: Red Sea, Arabian Sea to South China Sea, East China Sea and northern and north-western Australia. It is a neritic, demersal species occurring from the coastline to about 110 m depth, but more abundant in the upper 40 m, particularly during the reproductive season, when it migrates shoreward and aggregates in shallow waters (Fishbase, 2011; Fahmy Mehanna et al., 2014)
The fishermen in the coasts of the Sultanate in the governorates of Dhofar, Al Wusta and South Al Sharqiyah are hauling large quantities of squid marking the start of the squid season. Al Ghatro or squid season continues until the end of December.
Squid hauled in 2018 season reached 16,154 tonnes compared to 9,504 tonnes in 2017. The Governorate of Al Wusta topped the season with 6,558 tonnes, followed by South Al Sharqiyah with 4,137 tonnes, Dhofar with 2,620 tonnes, North and South Al Batinah with 2,140 tonnes, Musandam with 381 tonnes and Muscat with 317 tonnes.
Squid is found along the coastal strip of the Sultanate, especially in the Arabian Sea, which extends from the coast of Ras Al Hadd to the coasts of Governorate of Dhofar, and is considered a seasonal fish, on which a lot of fishermen depend as it constitutes a source of livelihood for them.
The price per kilo is between RO 1,200 and RO 1,700 according to demand, supply and quantities. The squid is exported to many Gulf, Arab, Asian, European countries.
In the late 1990s studies on the distribution, reproductive biology and culture of three oyster species (Saccostrea cucullata, Crassostrea rhizophorae and Crassostrea spp.) were conducted. To date none of these bivalve species are commercially farmed. (FAO, 2020)
Since 1997, the ministry has been engaged in different research and development projects on fish and shellfish culture. These included the investigations on abalone hatchery, mussel and oyster culture, shrimp farming and pilot trials on the cage and pond culture of finfish, suitable site selection for aquaculture, development of feed for cultured aquatic animal, hatchery development for finfish, sea cucumber aquaculture and development of freshwater integrated Tilapia farms in Oman.(Oman Observer , 2017)
In June 2013, a multi-million aquaculture project known as the “Sultanate Oman Qurun Aquapolis” was launched. The Lim Shrimp Organization (a social enterprise developer that helps developing countries build up sustainable livelihood programmes such as fish farming) in partnership with Bank Sohar and Arabian Marine Development, LLC, will jointly develop a 700 hectare, multi-species integrated aquaculture farm in Ras Jibsh, located approximately 300 km south of Muscat along the Arabian Sea. The species to be cultured include tiger shrimp (Penaeus monodon), Indian white shrimp (P. indicus), sand fish sea cucumber (H. scabra), Salicornia (an edible, salt tolerant plant also known as pickleweed), oysters and other bivalve species. When fully operational, the farm aims at producing annually about 4 500 tonnes of shrimp. The project is scheduled for completion in 2016. A total of 700 employees will be recruited for the project. The project will have its own feed mill, processing plant, cold storage facilities, hatcheries, desalination plant, standby power plant, sewage treatment plant, incinerator and other social amenities like shops, clinics, churches, mosques, a sport complex and a social hall. (FAO, 2020)
The sea cucumber fishery in the Sultanate of Oman is centered on one species, the Holothuria scabra. The H. scabra fishery is limited on the eastern side of Mahout Bay area in Al-Wusta region, which is characterized by seagrass beds with fine sand in sheltered lats and lagoons. H. scabra is considered one of the most commercially valuable species for beche-de-mer production and have been widely fished in the tropics. The A-grade classification of beche-de-mer from sandish H. scabra commands one of the highest prices on the international market. China has become the largest producer of sea cucumber worldwide.
In the Arabian Gulf and the Sea of Oman, sea surface temperatures in the same summer period often exceed 32°C, whereas in the winter, water temperatures drop to below 22°C. Despite these extremes, coral communities flourish along the hard-substrate shores and support a rich echinoderm fauna. There is only one marine protected area (the Daimaniyat Nature Reserve) in the Sea of Oman, and it covers about 20 km2 and encompasses a string of nine small islands. In total, 17 species of Aspidochirotida, 2 species of Apoda and 2 species of Dendrochirotida were observed during the survey. Additional species of Dendrochirotida were observed in the south of Oman. Although eight species were found in all or nearly all locations, many others were only found in four locations or fewer. Holothuria scabra, for instance, was restricted to two locations on the Arabian Sea near the Island of Masirah, and Holothuria arenacava was only found in a few sandy embayments near Muscat. The overall number of species decreased from the Arabian Sea (19 species) to the Sea of Oman (13 species) to the Arabian Gulf (8 species). Several species were recorded for the irst time during the survey: Holothuria arenacava, H. nobilis, a common yet unidentiied species of Holothuria, H. cinerescens, and a mottled pink Actinopyga, these last three were from Dhofar (southern Oman). Holothuria hilla and Holothuria impatiens were also observed. From a community standpoint, both the non-metric multidimensional scaling analysis and the cluster analysis, identiied a major split in the structure of sea cucumber communities between the Arabian Sea and the Sea of Oman. This irst subdivision is mainly due to six species that were restricted to the Arabian Sea coast of the Sultanate: Holothuria scabra, H. nobilis, Actinopyga miliaris, Actinopyga sp. (unidentiied species), H. cinerescens and an unidentiied species of Holothuria sp. Secondary subdivisions of communities distinguish the northern part of the Arabian Sea coast from its most southern part (Dhofar). In the Sea of Oman, sea cucumber communities from the central part of the Gulf (Muscat) are separated from those in the northern and southern regions. The holothuroid community found near Mahout Island appeared to be relatively distinct from both that of the Arabian Sea and the Sea of Oman.
STATUS OF SEA CUCUMBER FISHERY IN OMAN There have been very few studies conducted on the fishery of sea cucumber in the Sultanate of Oman. Harvesting of sea cucumber mainly Holothuria scabra, constitutes a minor fishery in Oman which takes place in Mahout Bay. Due to the increased demand for beche-demer in the international markets, a revived sea cucumber fishery was noted in 2003. The fishery is usually linked with the shrimp fishing season that runs from September to March. However, sea cucumber harvesting is done only when the number of shrimp landings decreased usually during November. Despite the lack of regulations in the harvesting of sea cucumbers, some general fishery management rules are being practiced in the region such as the restriction on the use of SCUBA for harvesting any marine resource. Sea cucumbers are only collected by hand during lowtide or by skin-diving in deeper areas. The peak months for harvesting sea cucumber are from September to January, despite the lack of specific closed season. Studies showed evidences of rapid overfishing of sea cucumbers in Oman. Recently, the average harvest per fisher in 2007 was only less than 20 per fishing trip compared to about 100 sea cucumbers per fisher per fishing trip in 2005. In 2005, 50% of the fishers were Women, and because of the stock depletion their percentage has dropped in 2008 down to 15%.
Processed sea cucumbers showed a significant number of very small individuals of less than 6 cm (dried form) which correspond to about 12 cm of live specimens. (Al Rashdi et al., 2012; Claereboudt and Al-Rashdi, 2011)
Holothuria scabra is considered as one of the most valuable sea cucumber for bêche-de-mer production and have been widely fished and overfished in the tropics . It is currently valued at more than 1000 US$ per kg dry weight , and the demand from the Asian market remains strong . This increasing demand from Asian markets driving high price, an often inadequate management of the fishery and the biological characteristics of the species such as slow growth and easy to access shallow water habitat resulted globally in severe overfishing . To avoid overexploitation of natural populations while maintaining a sustainable level of exports, aquaculture is considered as one of the potential solutions for H. scabra production . Several countries have progressively developed a viable aquaculture production and in some cases have initiated restocking or sea ranching programs . Although the sea cucumber Holothuria scabra has always been a small part of the traditional exploitation of the benthos in Mahout Bay of Arabian Sea , the foreign demand for the product overseas and its high price have put increased pressure on this resource locally leading rapidly to overfishing.
The natural spawning of this species in Oman has been recently documented and showed, as in many other locations, an annual reproductive cycle . Natural maturation occurred in February and March followed by spawning in April and May, which is correlated to high sea surface temperature and precipitation as both may serve as exogenous synchronizing cues for gamete maturation and spawning . Alarming signs of the of the Omani population of H. scabra overfishing have been observed with stock densities decreasing to less than 1 individual per ha , a regular decrease in the size of animal processed and a progressive switch to less valuable species in only a few years of exploitation. Therefore, restocking and stock enhancement in addition to fisheries management policies are needed to ensure the sustainability of this resource. the first attempts made to develop hatchery techniques for the Omani sea cucumber Holothuria scabra population as initial steps towards aquaculture development and stock enhancement programs.