The importance of crabs should be considered when looking at increasing human pressure on the Barr al Hikman nature reserve, a new research has revealed.
The intertidal mudflats of Barr al Hikman, a reserve in the southeast coast of the sultanate, are crucial nursery grounds for numerous crab species. In turn, these crabs are a vital element of the ecology, as well as the regional economy, a new study in the scientific journal Hydrobiologia shows.
“The important function of the crabs should be considered when looking at the increasing human pressure on this nature reserve,” first author and Royal Netherlands Institute for Sea Research researcher Roeland Bom said.
The mudflats of Barr al Hikman are home to almost 30 species of crabs. For his research, Bom, together with colleagues from the Netherlands and at Sultan Qaboos University, looked at the ecology of the two most abundant species (Macrophthalmus sulcatus and Thalamita poissonii).
“Barr al Hikman is home to the blue swimming crab – Portunus segnis – the species caught by local fishermen. This crab uses the mudflats of Barr al Hikman as nursery grounds.”
According to Bom and his colleagues’ count, there are millions of these crabs in the reserve. They are food to hundreds of thousands of birds, both migratory species as well as birds that breed in the area, such as crab plovers.
The crustaceans live in holes in the ground and forage on the seagrass found in abundance in the reserve.
“Apart from the high production of algae in Barr al Hikman, the reserve is also well suited for crabs because of the vastness of the area,” Bom explained.
“The slopes of the mudflats are very gentle, so at low tide, the crabs have an immense area at their disposition.”
According to Bom, the crabs have more than just ecological value.
“The blue swimming crabs caught here are sold not only throughout Oman, but the rest of the Arabian Peninsula and as far as Japan. At approximately €2 per kilo, these crabs represent an important economic pillar both for the region around Barr al Hikman as well as for the whole of Oman.”
Efforts currently continue to include the reserve in the Ramsar Convention on Wetlands of International Importance – an international treaty for the conservation and sustainable use of wetlands.
With increasing human pressure on Barr al Hikman, the authors have called for further protection of the mudflats.
“There are well-developed plans to start shrimp farming around this intertidal area. When looking at the cost and benefits of these activities, it is important to look at the role of this reserve in the local ecology, as well as in the broader ecology of the many migratory birds that use the area,” Bom said.
“Our research shows that the unique ecosystem of Barr al Hikman plays a key role in the economy as well.”