The platform being created by the EU-funded HiSea project (High resolution Copernicus-Based Information Services at Sea for Ports and Aquaculture) will be a “great help” for aquaculture in the sector’s struggle with red tide and other toxic algae and eutrophic hazards, according to experts at HiSea aquaculture partner Selonda.
“Traditional systems regarding identifications of such problems cannot provide to us instant success and the ability to pro-act. Such weaknesses could lead to huge economic disaster, even the bankruptcy of aquaculture producers,” warned Selonda’s Andreas Marountas.
“Monitoring and forecasting of harmful algal blooms is a must these days. A satellite-based forecasting system, such as the HiSea platform, can provide real-time information on such topics as early warning and detection, synoptic monitoring and prediction models, leading to a better understanding of causes and effects, and contributing to environmental conservation, the saving of flora and fauna, action towards mitigation and proactive responses,” Marountas said, calling it “ideal”.
Factors that could be tracked through HiSea to help detect such blooms as they emerge include oxygen levels, dissolved solids, nutrients, chlorophyll, nitrates and phosphorus, alongside sea-surface photometric data.
To demonstrate the consequences of a “red tide” crisis in the absence of real-time detection, Marountas described a fish kill event of unusual scale, which took place in the Maliakos Gulf (on the Aegean coast of central mainland Greece) over a period of more than four weeks during the spring of 2009.
Dead fish appeared by the thousands at different points along the Gulf’s coastline and a large number of them were examined and checked for all kinds of potential causes of death. Analyses were done simultaneously by a long list of laboratories to check for heavy metals, pesticides, parasites, various diseases and infections.
After an enormous loss of fish, finally water quality analyses done by the Hellenic Centre for Marine Research (HCMR) successfully identified the problem as toxic algae, a full month after the initial outbreak. Two days later, Aristotle University of Thessaloniki’s Biology Department laboratory confirmed this diagnosis.
“The lack of a rapid method of detection for the problem, plus the limited social trust in public administrators and the adverse media interpretation during communication of the event, exacerbated the effects of the crisis on the local behaviour of the coastal society”, Marountas noted, highlighting HiSea’s expected importance.
Fish kill losses and the large numbers of dead fish washing up on the coast adversely affected the incomes of local fishermen and fish farming operations, as well as other sectors. The mass mortality event impacted residents, consumers of local seafood products and tourism long thereafter.
Identification of the catastrophe’s cause taking so long was not unusual; in the absence of a service such as HiSea, a diagnosis pertaining to fish health in relation to environmental stressors can normally take up to two months before a clear causal etiology of mass mortalities is established.
Greece’s coastal areas include a wealth of gulfs and basins that are ideal for aquaculture development, but also favour eutrophic phenomenon since they receive the water and fertile material draining from urban, agricultural and industrial areas, Selonda said in the summary document, highlighting the need for improved detection methods such as that provided by the HiSea platform.
At least sixteen species of algae have been associated with the occurrence of significant harmful algal blooms, causing damage to the aquaculture sector, marine life, and overall water quality. These phenomena are likely related to the anthropogenic eutrophication prevailing in the investigated areas.
Routine phytoplankton samples taken along the Greek coastline during the last thirty years have revealed the constant presence of toxic and potentially toxic algae, as well as non-toxic large biomass-producing species (susceptible of causing harmful blooms), Selonda noted.