Jellyfish are important plankton in the aquatic environment, as a large group of colloidal zooplankton, including hydra jellyfish, tube jellyfish, bowl jellyfish, cubic jellyfish and ctenophores of the ctenophore phylum 5 categories.
The extremely simple biological structure and high affinity for seawater allow jellyfish to adapt to almost any marine environment. From the Caribbean Sea near the equator to the polar ice oceans, from shallow bays around the world to the deep ocean floors, there is no place for jellyfish to deter, even next to the hot magma flowing from the crater of the ocean more than 8,000 meters deep.
Jellyfish can be said to be a very ancient creature, it is said that in the Cambrian era 550 million years ago, it was the hegemony of the ocean, but later, fish became the hegemon of the ocean, but now, the famous scientist Ferdinand Burrow warned that the ocean is afraid of returning to the era of jellyfish rule.
<h1 class="pgc-h-arrow-right" data-track="3" > jellyfish flooding around the world</h1>
In recent years, the global jellyfish began to breed in large quantities, at least 14 seas around the world often have jellyfish outbreaks, including the Black Sea, the Mediterranean Sea, the United States Hawaii coast, the Gulf of Mexico, the Sea of Japan, etc., the scale and frequency of jellyfish outbreaks worldwide far beyond the limits of self-regulation of marine ecosystems, forming a catastrophic outbreak.
The biomass of large jellyfish jellyfish in the eastern Bering Sea increased 10-fold in the 1990s compared to the 1980s, and the marine moon jellyfish in the Black Sea reached about 300-500 million tons in the late 1980s. Large-scale jellyfish outbreaks have also occurred in the Liaodong Bay of the Bohai Sea, the northern part of the East China Sea and the southern part of the Yellow Sea in China, and there is a trend of aggravation year by year.
The reason why jellyfish flood is caused by climate change, environmental pollution and overfishing, etc. With the warming of the climate, the increase in seawater temperature makes the distribution range of jellyfish wider, and tropical jellyfish gradually move to subtropical and temperate regions. At the same time, seawater warming makes the temperature range suitable for the hydra body fracture process longer, resulting in more discs and jellyfish larvae, providing suitable conditions for the outbreak of jellyfish populations.
Human activities (e.g., eutrophication, fishing, aquaculture, invasion of non-native species, construction of dams, nuclear power plants, etc.) have caused changes in the offshore ecological environment, which may have created conditions for the mass growth of jellyfish.
Humans take the upper trophic level in marine ecosystems - fish too much from the ocean, the reduction of jellyfish-fed fish (such as: salmon, pomfret, horn sharks, etc.) means that the natural enemies of jellyfish are reduced, which is conducive to the growth of jellyfish; secondly, overfishing fish that feed on other zooplankton, because they overlap with jellyfish's bait, for jellyfish, the reduction of these fish means that the reduction of bait competition, which is also conducive to the growth of jellyfish.
Another reason for this is biological invasion, through ballast water, or through trade between aquariums, newly invaded jellyfish species usually multiply in large numbers at the beginning, such as ctenophores invading the Black Sea and destroying the Black Sea's fisheries, with a total weight of about 1 billion tons at its peak, about equal to the weight of all the catched fish in the ocean that year.
<h1 class="pgc-h-arrow-right" data-track="3" > jellyfish hazards</h1>
Jellyfish multiply in large numbers will prey on large numbers of zooplankton and cause a decrease in plant-feeding zooplankton. The reduction of plant-feeding zooplankton reduces the pressure on algae to be fed, and eventually causes algal outbreaks and changes in plankton community structure.
In addition to preying on plankton, jellyfish can also adversely affect the survival of fish by preying on fish eggs and baby fish, competing for food with fish that feed on baby fish and zooplankton, and acting as an intermediate host for fish parasites. Therefore, the increase in jellyfish biomass further leads to a decrease in the number of fish, which continues to worsen this bad cycle, and jellyfish is also known as the "killer of the sea".
In summary, the mass reproduction of jellyfish will undoubtedly destroy the chain of marine life, which may cause a fatal blow to marine life, and it is not nonsense that the ocean has become a jellyfish world. This is also why Ferdinand Burrow warned that the ocean fears a return to the era of jellyfish rule.
For example, in many parts of the world, in recent years, when people are stung by jellyfish when they are fishing, farming or swimming, poisoning or death occurs frequently, 150 million sea bathing enthusiasts and fishermen around the world are deeply troubled by jellyfish, and 200,000 people are stung by jellyfish every year in Florida, USA.
During jellyfish outbreaks, being stung by jellyfish may even reach the level of plague, and if unfortunately encountering a highly toxic jellyfish, there is even a fatal danger. Dangerous jellyfish are often found on Australia's waterfront, and the infamous box jellyfish is the most toxic jellyfish in the world, mixing almost all types of toxins possessed by various poisonous animals and can kill people in a matter of minutes.
The increase in jellyfish production interferes with fishery production, and the presence of large tides of jellyfish in fishing operations can block nets, damage fishing gear and, in severe cases, cause vessels to roll over. Large jellyfish prey on small juvenile fish and fish eggs and compete with other economical fish and shrimp that prey on zooplankton, resulting in severe losses in fisheries. It has seriously affected the development of offshore marine fisheries, coastal industry, coastal tourism and the health of marine ecosystems.
In addition, it is not uncommon for jellyfish to block the inlet sieve of cooling water from power plants, desalinated water plants and nuclear power plants.
Many people say that jellyfish can be caught and made into jellyfish to eat, but most of the jellyfish that cause disasters are not jellyfish (a type of jellyfish) that people often eat, but sand jellyfish, sea jellyfish and kasumi jellyfish that have very low or no use value.
<h1 class="pgc-h-arrow-right" data-track="3" > summary</h1>
Jellyfish outbreaks are marine disasters closely related to human activities, reflecting the imbalance and deterioration of the marine environment. If the ocean really returns to the era of jellyfish rule, it will have an irreparable impact on global fisheries and marine resources.
Therefore, understanding the causes of jellyfish outbreaks, scientifically monitoring the reproductive process and drift trajectory of hydras and jellyfish, and exploring the solution to jellyfish outbreaks will be hot spots and priorities in related research fields in the future.