Climate changes affecting aquaculture are reflected by temperature changes in both water and air, particularly surface temperatures in marine conditions and other alterations in oceanographic conditions, including currents, wind speed, and waves.
Rising temperatures can directly affect the metabolism, life cycle, and behavior of marine species. For many species, temperature serves as a cue for reproduction. Clearly, changes in sea temperature could affect their successful breeding. Rising ocean temperatures and ocean acidification are radically altering aquatic ecosystems. Climate change is modifying fish distribution and the productivity of marine and freshwater species. This has impacts on the sustainability of fisheries and aquaculture, on the livelihoods of the communities that depend on fisheries, and on the ability of the oceans to capture and store carbon (biological pump). The effect of sea-level rise means that coastal fishing communities are in the front line of climate change while changing rainfall patterns and water use impact on inland (freshwater) fisheries and aquaculture. The full relationship between fisheries and climate change is difficult to explore due to the context of each fishery and the many pathways that climate change affects.
Impact on fish production:
The rising ocean acidity makes it more difficult for marine organisms such as shrimps, oysters, or corals to form their shells – a process known as calcification. Many important animals, such as zooplankton, that forms the base of the marine food chain have calcium shells. As a result, the distribution, productivity, and species composition of global fish production is changing, generating complex and inter-related impacts on oceans, estuaries, coral reefs, mangroves and seagrass beds that provide habitats and nursery areas for fish. Changing rainfall patterns and water scarcity is impacting on river and lake fisheries and aquaculture production. The global air temperature has risen 3 degrees, leading to an increase in sea temperatures.
Due to climate change, the distribution of zooplankton has changed. Cool water cope-pod assemblages have moved north because the waters get warmer, they have been replaced by warm water cope-pods assemblages however it has lower biomass and certain small species. Atlantic cod require a diet of large cope-pods but because they have moved pole-wards morality rates are high and as a result, the recruitment of this cod has plummeted.
Impact on fishing communities:
Coastal and fishing populations and countries dependent on fisheries are particularly vulnerable to climate change. Low-lying countries are particularly vulnerable and entire communities may become the first climate refugees.
Climate change changes several parameters of the fishing population: availability, stability, access, and utilization. The specific effects of climate change on these parameters will vary widely depending on the characteristics of the area, with some areas benefiting from the shift in trends and some areas being harmed based on the factors of exposure, sensitivity, and ability to respond to said changes. The lack of oxygen in warmer waters will possibly lead to the extinction of aquatic animals. Worldwide food security may not change significantly, however rural and poor populations would be disproportionately and negatively affected based on these criteria, as they lack the resources and manpower to rapidly change their infrastructure and adapt. Over 500 million people in developing countries depend, directly or indirectly, on fisheries and aquaculture for their livelihoods – aquaculture is the world’s fastest-growing food production system, growing at 7% annually and fish products are among the most widely traded foods, with more than 37% (by volume) of world production traded internationally.
A number of studies have been conducted in Ghana. One of such studies conducted in 2015 indicates that in the coastal area of Accra, Ghana, fish catch has significantly decreased over the last two decades as average sea surface temperatures have steadily risen. For example, the catch of round sardinella, a climate-sensitive species, decreased by 75% between 1992 and 2010.
- Fishers are becoming highly indebted due to reduced fish catch, increasing risks and growing investment costs. With limited alternatives for livelihood, small scale fishers are highly vulnerable to the impacts of climate change. New livelihood options need to be identified and training will need to be provided.
- The end of the rainy season traditionally signals the start of the main fishing season, but this is becoming unpredictable due to variability in rainfall distribution patterns, increasing the risks of investment for fishers and exacerbating poverty and indebtedness.
- The Marine Fisheries Research Division (MFRD) and meteorological authorities should intensify data collection and monitoring activities, to improve forecasting about the onset and productivity of the fishing season, and should make this information available to fisherfolk.
Thus, I can fairly argue that implementation of laws or regulations against illegal methods as well as the observation of the appropriate period for the closed season are not enough to assuage the depleting fish stock
Reason why we ought to #StandTogetherNow and demand #ClimateActionNOW