Photo credit: Sharmala Naidoo (South Africa)
Review: Abdel Rahman El Gamal (Website founder)
Introduction: Cuttlefish are sea molluscs that belong to the order Sepiida and to the Cephalopoda class. The photo that shows a specimen of “Pharaoh Cuttlefish” was taken at Sahar landing site, the Sultanate of Oman. The pharaoh cuttlefish (Sepia pharaonis) is a large cuttlefish species that may exceed 40 cm in mantle length and 5 kg in weight. The average longevity of the species is between 1-2 years. The Pharaoh cuttlefish ranks high among the fish export list from Oman.
Distribution and habitats: Its regional distribution includes Red Sea, Arabian Sea, Oman Sea and is also found in wider geographical areas. The Pharaoh cuttlefish is demersal species and occurs in water depth of 100-130 meter, but during the reproductive season, the species is more abundant in the top 40 meters for mating.
Special biological features:
Reproduction: Spawning times vary depending on habitats. After mating, the female deposits her eggs near the coast, between depths of 5 and 20 m.
Feeding: When hunting at night, the Pharaoh cuttlefish swims up to shallower depths to feed on small mollusks, crabs, shrimps, small fishes, octopuses, worms, and occasionally other cuttlefish. On the other hand, its predators are dolphins, sharks, big fishes, and birds.
Camouflage: The Pharaoh cuttlefish can camouflage to avoid its predators.
Harvesting: The light attracters are used to catch larger species of cuttlefish at night. Also, the cuttlefishes are caught in large numbers during full moon days and fog season.
Utilization: In the past, the cuttlefish was caught and treated as bycatch with almost no commercial value in most of its distribution region including Oman. During 90’s, the attention paid to the importance of the species for human consumption led to the upgrading the species to a much higher category to become a valuable and target species for artisanal and industrial fisheries in Oman. The contribution of cuttlefish in Oman amounted about 16% of the demersal total catch with significant economic returns in 2011. It is believed that Omani cuttlefish are in high demand due to their thick flesh and bigger sizes. The Sepia pharaonis has been proposed as a promising species for mariculture due to its high spawning success, rapid growth rate, disease resistance and tolerance of crowding and handling.
Threats and conservation: The over fishing of cuttlefish is considered a major threat to their populations especially when done during the spawning season. Also, ocean acidification is a potential threat to all cuttlefish and may negatively affect buoyancy regulation of the species. In regard to conservation measures, governing the cuttlefish catch seems the practical method for the conservation of its stocks.
References: Wikipedia, Oman Fisheries Company, Encyclopedia of Life, IUCN, scientific papers