After Storm Harry: Can Offshore Aquaculture Survive the New Mediterranean?
In mid January 2026, Storm Harry (a powerful Mediterranean extratropical cyclone) unleashed unprecedented rainfall, flooding, and severe sea conditions across North Africa and Southern Europe, including Tunisia, where aquaculture operations along the northern coast suffered heavy losses.
Meteorological services reported rainfall amounts not seen in over 70 years in several regions of Tunisia during the storm period of 19-25 January, with totals exceeding 200 mm in a single day. These levels far surpassed historical averages and led to widespread flooding, submerged streets, and disruptions to daily life.
In the governorates of Monastir, Nabeul, Sousse, Beja, and Greater Tunis, authorities recorded exceptional rainfall, forcing schools and public services to close and leaving some communities isolated by floodwaters. At least four people were reported killed by flooding, highlighting the human toll of this extreme weather event.
During Storm Harry in January 2026, the Mediterranean experienced exceptionally violent wind and sea conditions. Monitoring buoys recorded wave heights up to 13 m (about 43 ft) off Malta – the highest measured in Maltese waters during the event – and even up to 16 m in the wider Sicilian Channel, illustrating the Tank-like swell hitting the region. Peak wind gusts of around 95 km/h (about 26 m/s) were observed simultaneously with strong near-surface currents reaching around 80 cm/s (~4.6 km/h) as the storm persisted for nearly 40 hours in some sectors of the central Mediterranean. Such conditions created prolonged high sea states and hazardous maritime environments, with hurricane-force winds and towering swells battering coastlines and infrastructure, far exceeding typical Mediterranean storm thresholds and underscoring the extreme nature of the event.
Offshore Fish Farms hit hard
The extreme wind speeds, powerful currents, and unusually high waves had a direct and destructive impact on both coastal and offshore aquaculture systems. Cage structures, mooring lines, and floating platforms are engineered for historical Mediterranean storm norms, not for prolonged 13-16 m swells combined with strong surface currents and hurricane-force gusts. The result was structural fatigue, broken moorings, displaced cages, and massive fish escapes. In coastal areas, sediment resuspension, turbidity, and sudden salinity fluctuations further stressed farmed organisms and infrastructure. Such oceanographic conditions turn aquaculture installations into highly vulnerable assets, demonstrating how climate-driven storm intensity now exceeds the operational safety margins on which many farms were originally designed.
For Tunisia’s offshore aquaculture sector, Storm Harry was not simply a severe weather episode; it was a structural shock that exposed how vulnerable marine cage farming has become to increasingly violent sea conditions.
Several offshore aquaculture farms located along the northern half of Tunisia’s coastline were contacted, all of which reported being affected to varying degrees depending on their exposure, bathymetry, and distance from shore. The accounts were strikingly similar:
- Entire cages were torn apart or displaced by the combined effect of wave height, strong currents, and prolonged agitation of the sea surface.
- Large quantities of fish escaped when nets ruptured or cages collapsed.
- Losses occurred despite the presence of controlled and professionally engineered mooring systems designed according to current standards for offshore aquaculture.
Farm operators shared photographs showing broken floating collars, twisted net pens, snapped mooring lines, and deformed anchoring structures, clear evidence that the storm exceeded the design thresholds typically considered sufficient for Mediterranean conditions.
Even more alarming was what happened after the storm.
Local fishermen were seen recovering escaped fish and selling them at very low prices in nearby markets. Many of these fish were already at commercial size, ready for harvest, and in several cases destined for export markets. This transformed what should have been the final, most profitable stage of the production cycle into an abrupt economic loss.
According to Mr. Foued Nakbi, Director General of an offshore aquaculture farm, who also spoke on behalf of the National Federation of Aquaculturists in Tunisia, “this storm was not like the others.” He emphasized that the sector has experienced difficult weather in the past, but never at this scale of structural damage and biomass loss in such a short period.
The financial impact is twofold:
Immediate capital loss from destroyed cages and infrastructure.
Production cycle disruption, as the loss of market-size fish erases months of feeding, labor, and operational costs, while delaying the next stocking cycle.
A Pattern, Not an Exception
Aquaculture professionals insist this is not the first climate-related stress the sector has faced. Over recent years:
- Rising sea temperatures,
- Increased frequency of storms,
- Unusual current patterns,
- And prolonged extreme events
have gradually altered farming conditions.
The same pattern is visible in conchyliculture in the Bizerte Lagoon, where shellfish farmers have experienced repeated losses linked to temperature spikes, water quality fluctuations, and ecological imbalance. Comparative photos taken over the years show visible degradation of farming conditions before and after other previous extreme climate events.
Storm Harry, therefore, should not be seen as an isolated disaster, but as part of an accelerating trend where climate variability is directly reshaping the operational reality of aquaculture in Tunisia.
Farm operators note that this is not the first time aquaculture has felt the impact of shifting climate patterns. Bivalve producers in the Bizerte lagoon, for example, have reported recurring losses tied to heatwaves, algal fluctuations, and salinity changes over recent years, further illustrating how climate stressors compound across sectors.
Learning from Loss: What comes Next?
As Tunisia navigates recovery, adaptation and mitigation must be priorities for the aquaculture sector:
- Climate-resilient farm design, stronger cages, adaptive mooring systems, early warning integration.
- Insurance and risk pooling, to protect producers from climate-driven economic shocks.
- Data-driven planning, combining meteorological forecasts with aquaculture site selection using modern GIS and remote sensing.
- Public-private collaboration, leveraging national and regional climate action plans to safeguard coastal food economies.
Tunisia’s aquaculture and the wider Mediterranean marine economy cannot view climate change as a distant threat. Storm Harry has shown that climate variability is now embedded in the daily risk landscape, reshaping not only nature but the businesses and communities that depend on it.
For many producers, the conclusion is becoming unavoidable: the current design standards, risk models, and management approaches used for offshore aquaculture are no longer fully aligned with the new climate reality of the Mediterranean. At the same time, many of these emerging climate-related risks are not adequately covered by existing insurance schemes, leaving farmers to bear massive financial losses alone. This growing gap between real climate exposure and insurance coverage is making it increasingly difficult for aquaculture farms to survive repeated extreme events. In the near horizon, updating and adapting design standards, risk assessment models, and management practices to this new climate context is no longer an option, it is becoming the only viable path for the sector’s survival.
After Storm Harry: Can Offshore Aquaculture Survive the New Mediterranean?
