Aquaculture in Cyprus aims in the sustainable development of the sector in order to maximize production and at the same time maintain environmental consciousness. At present, aquaculture production in Cyprus accounts for about 70% of the national fisheries production and over 70% of the value.

During the latest decade marine aquaculture in Cyprus has most certainly been one of the fastest growing food production industries. Fish farming efforts however had initiated many years ago but lately expanded to include mainly open sea cage farms (read a brief history of the national aquaculture sector). Due to water shortage reasons, freshwater aquaculture is limited to small scale trout farming on the Troodos range. Most fish farms are now open sea cage systems culturing mainly sea bream and sea bass and fattening blue fin tuna and are located in Vasiliko Bay (south coast), adjacent to the Limassol harbour (south coast) and off the coast of Liopetri (southeast coast). Most farms are located about 1 to 2 kilometres off the coast, at water depths of ~30 meters. Some farms (mostly those that fatten blue fin tuna) are in deeper waters (~70 meters). The policy of the Department of Fisheries and Marine Research is that any expansion or establishment of new units to be done in deeper waters and further off shore.

Fish farming activity can cause irreversible changes to the environment. The main problem associated with open sea cage farming are the organic effluents (uneaten fish feed and fish excretions) released by the fish farming process which inevitably result in organic enrichments of the water column and the benthos in the vicinity of the fish farm. The organic solid particles deposit on the sea floor, adversely impacting the established natural communities. Sedimentation rates increase and water clarity decreases and as a result, all primary producers are struggling to survive as their photosynthetic tissues are covered by sediment and the light availability is reduced. Upon their loss all subsequent food chains gradually collapse. All these once living organisms become detritus and together with the organic effluents released by the farm, contribute to elevated levels of organic matter on the sea floor. These organic enrichments of the sediment result in a population bloom of decomposing microorganisms. Saprobionts and detritivores are decomposing organic matter at high rates but being aerobes they quickly exhaust the levels of oxygen in the sediment promoting the development of anaerobic decomposing bacteria. The anaerobic bacteria can continue decomposition in the absence of oxygen but produce toxic substances such as methane and hydrogen sulphide. Overall, the biogeochemistry of the sediment is altered and it becomes an inhospitable habitat to most marine species. The extent of this impact can be affected by several reasons such as climatic conditions, current magnitude and direction, depth of the site, amount of fish feed supplied, fish stocks and densities, cage distribution, as well as, biotic and abiotic characteristics of the benthos. What’s more is that the reduced sediment quality can result in deteriorating water conditions and hence an unhealthy environment for the fish cultured.

What has been discouraging to us is the fact that several times, fish farms across Cyprus have been placed years ago; above extensive Posidonia oceanica seagrass meadows resulting in their gradual decline and eventually the irreversible loss of vital, endemic to the Mediterranean habitat. The presence of extensive dead matte (root structures, remnants of the seagrass) below the farms and unproductive, struggling patches of seagrass that still survive are proof to the once thriving seagrass systems.

The case of blue fin tuna (Thymus thymus) is also showing worrying signs. During the last years the scientific community across Europe was largely worried of the declining Mediterranean blue fin populations largely attributed to overfishing. After several years of ongoing fishing activities in the eastern Mediterranean; the blue fin fattening units of Cyprus returned from their fishing voyage this season, for the first time ever, fishless!!! Could this be, because of blue fin tuna population decline or just to the fact that the fishermen have not timed their arrival at the fishing grounds to match the migration of blue fin tuna. Soon we’ll know…….

It is vital that research regarding the aquaculture industry is promoted. Detailed studies should be undertaken prior to the establishment of the farm, during production and after cessation of all activities (it could be best that a farm is moved to allow for the recovery of the affected site). There are numerous applicable methods that could maximize production and mitigate negative environmental impacts. We have just prepared a research proposal that involves the application of biofilters adjacent to the fish farm where they will act as a substrate for the attachment of many organisms that have biofiltering capabilities and will subsequently result in mitigation of the organic loads to the benthos, reducing the decline of species and improving habitat quality (read more about this in the Projects section).

From simple aquaculture managemental decisions to detailed research projects, MER’s expert personnel can undertake all requests by customers. MER’s staff has completed several small scale projects and EIA studies on the related subject. MER is currently responsible for the general managing of Seawave Fisheries Ltd. Fish farm owners, universities and public bodies can cooperate with MER to monitor, improve productivity and reduce the adverse environmental impacts of fish farms. We can now suggest mitigation strategies.

For more information about the aquaculture industry of Cyprus read the aquaculture national report prepared by MER for Food Agriculture Organization (FAO) of the United Nations in the Projects section.

Services that MER can now offer:

• Fish disease diagnostics
• Looking at the health state of fingerlings and observing for skeletal and body deformities
• Monitoring the fish growth in the cages
• Inspecting and estimating the food supply (quality, feeding strategic methods, food conversion ratio, and daily estimations of fish nutrition)
• Image processing analysis (weight estimator) of the fish population in the cages, important parameter for the fish-food quantity estimation
• Underwater monitoring and maintenance of the mooring-cages system
• Environmental management of fish farms and aquaculture systems, from how to start a farm, to annual monitoring and advice on further development
• Proposing and applying monitoring assessments and mitigation measures that reduce or neutralize the adverse impacts of the fish farms to the environment