"Pai Daxing Army" invaded Jiaozhou Bay, eating clams and scallops
How to deal with the heavy losses of fishermen?
Lin Zhishu, a researcher at the Marine Management Guarantee Center of the Qingdao Municipal Ocean Development Bureau, said that the large number of starfish in Jiaozhou Bay has become a biological disaster.
The marine authorities have also issued urgent measures to allow farmers to temporarily use "ground cage nets" in the breeding areas to speed up the cleaning of sea stars.
At the same time, merchants and citizens of Qingdao also joined the ranks of ordering starfish.
(According to CCTV News)
We have become accustomed to the use of nature as "free".
The starfish crisis just tells us again-It's wrong.
In the vastly acclaimed Yellow Sea of China, the "Army of Big Stars (Sea Stars)" is invading Qingdao Jiaozhou Bay violently.
According to CCTV News, Qingdao Morning Post and many other media reports, a large number of sea stars have recently appeared in the coastal waters of Qingdao Jiaozhou Bay, and each boat can catch one to two thousand catties or more per day.
Because of the large number, fishermen use baskets to carry the starfish to the shore, and transport them to the market in trucks.
The starfish looks good, but it is a "beauty killer".
Because starfish feed on clams and scallops, farmers have suffered serious losses.
After the Spring Festival this year, fishermen found a large number of starfish in the offshore area, and the clams they raised in the sea were also attacked by starfish and suffered heavy losses.
"A starfish is an omnivorous animal and eats everything. A starfish can eat 10 clams a day, which is an amazing number." Many starfish groups passed by, and the clams were eaten so that only their shells were left.
Experts say that sea stars have extremely strong reproductive capacity, and they have almost no natural enemies when they become adults, and there is no control method for the time being.
Starfish is rich in nutrients, and the more common ways to eat it are: steaming, cooking, steaming eggs, boiling soup, etc.
Many netizens have suggested that they can eat all the starfish, but is this method reliable?
In order to explore the causes of the starfish disaster and possible countermeasures, Chengdu Business Daily-Red Star News joined the Zhihu Q&A community to invite outstanding creators @一个男在流浪 (science blogger; excellent answers to topics such as animals, oceans, and marine life) ) Provide professional answers for us.
The starfish that was infested this time was Asterias amurensis, and the main clams that were afflicted were Ruditapes philippinarum (Ruditapes philippinarum).
This is not the world, the country, or even Qingdao's first encounter with starfish flooding, and I am afraid it will not be the last.
At this stage, there is no good solution to the starfish flooding, and the mechanism of its outbreak is also very complicated and elusive.
All answers that advocate using "eating" to deal with starfish disasters can be stopped.
This time the catastrophe-the spiny sea wheel
Let's first get to know the starfish, the protagonist of this flood-Asterias amurensis.
Starfish is the collective name for more than 1,500 species in 5 orders of the Echinoderm, Seastar. The spiny sea, which belongs to the Pneumococcus family, is the most common sea star species in the offshore Northwest Pacific.
In my country, thorny seas are basically only distributed in the waters of the Yellow and Bohai Seas, especially the shallow and cooler waters along the coast of the Liaodong Peninsula, the central Bohai Sea, the waters near Changdao at the junction of the Yellow and Bohai Seas, and the smoke in the northern Shandong Peninsula. Wei fishery nearby.
It can be seen that the coast of Qingdao belonging to the Yellow Sea was originally located in the natural distribution area of the spiny sea, so this starfish disaster is not a biological invasion.
As a typical carnivorous animal, the adult spiny sea carnivorous predator is very fierce. It especially likes to start with the hard bones painted along the beach-shellfish protected by thick shells.
When preying, the spiny sea scallop wraps the shell of the bivalve with its own wrist, and then pulls it directly left and right with brute force. The soft shellfish that has lost its hard shell protection is exposed under the mouth in the center of the abdomen of the spiny scallop. At this moment, the thorny sea tray will turn out one of its own stomachs, the cardia stomach, to wrap the food, and then swallow the food after partial digestion, and hand it over to the other stomach, the pyloric stomach, to process slowly while holding the cardia. The stomach retracted, looking for the next prey.
Because the digestibility is too low, the thorny sea panche must have a preference for food choices. It prefers those with moderate body size (shellfish that are too small are not enough to fill the stomach, and those that are too large generally have a thicker shell) , The adductor muscle is relatively weak (the adductor muscle is the secret to "holding" the double shell of bivalve molluscs. The strength of the adductor muscle directly determines the difficulty of the starfish "hardening" the shell), or rarely The shellfish hiding under the deep sand (to avoid the time it takes for the starfish to dig the shellfish) start, so the abalone with only one shell, the oyster that is completely exposed on the reef and cannot escape, and the story of this time The other protagonist, the Philippine clam, often becomes its "ghost under the stomach".
The Philippine clam (Ruditapes philippinarum) has different names in different parts of China. In a few places in Liaoning and Shandong Peninsula, it exists as a clam; in other parts of the Shandong Peninsula, clam is its exclusive name; continue to go south , People call it flower clam or flower beetle.
In recent years, the Philippine clam has an annual output of 3 million tons, accounting for 15% of the country's total mariculture production, and has consistently topped the list of species with the highest mariculture production in my country.
Especially in the two provinces of Liaoning and Shandong, the Philippine clams are the most important existence in coastal areas, no matter in terms of production or consumption.
In Qingdao, where the sea star invasion occurred, the Philippine clams are no longer a simple shellfish. The promotion of a large number of Qingdao stars has taught many foreigners a Qingdao dialect-"Drink (pronounced'ha') ) Beer to eat clams (pronounced'Gala')", drinking beer and eating Philippine clams while blowing the sea breeze is the most original style of Qingdao people.
According to statistics from previous years, Qingdao citizens eat at least 50 tons of Philippine clams every day.
Why are Philippine clams popular?
Because it is generous, delicious and easy to cook.
More importantly, the large scale of breeding brought about by the strong demand of coastal residents allows it to be found everywhere.
According to data, at the end of March 2007, the thorny sea clam disaster broke out on Red Island, the main producing area of Philippine clams in Qingdao. By mid-April, the affected area of Philippine clams in the Hongdao breeding area reached 60%. The infant mortality rate even reached 80%. A 60-horsepower fishing boat can catch more than one ton of thorny barge in a day, and Qingdao's output has lost more than 100,000 tons during the entire breeding season.
Just a year ago, in July 2006, Qingdao’s Laoshan, Huangdao, and Jiaonan had already suffered a round of "sea star invasion" composed of spiny sea trestle and petrel starfish, which was even worse than that in 2007. The tragic thing is that the farmed products in these areas are generally more expensive abalone and sea cucumbers. In Houwan, Huangdao Street, the worst-hit area, the losses of 10 abalone farmers have exceeded 10 million yuan.
In addition to the original habitat of the thorny sea bark, the ecological invasion disaster caused by it has also formed. In 1999, Tasmanian fishermen caught this kind of unseen starfish from the seabed. Since then, the thorny sea The sea trestle not only continues to harm the local shellfish farming industry, but also continues to move north along the coast of Australia. The sharp decline of the local endangered fish, the thick Australian scorpionfish, is also likely to be related to the spiny sea trestle, which is produced in algae. The egg masses in the cluster are preyed on by starfish.
It is reasonable to speculate that the larvae of the Spiny Sea Barge came to this new world with the ballast water of the freighter.
How did the thorny sea turning disaster break out?
According to the description of the old fisherman, sea stars have always existed, but I have never seen so many sea stars in flood before. This has to be linked to the rapid changes in the offshore ecological environment in recent decades-sea stars are not without natural enemies, a large number of fish, bottom Large snails can effectively suppress the population size of starfish, but with the vigorous development of offshore fishing, predatory marine fish resources with higher economic value are the first to deplete, which inadvertently raised the ceiling of the scale of starfish flooding.
Another point of view is that the proliferation of starfish is closely related to the rapid expansion of the scale of near-coastal aquaculture. The breeding of tidal flat shellfish makes it easier for the larvae of starfish to find food, and it also greatly promotes the carrying capacity of a certain sea area for the population of starfish. Facts have also proved that even during the Qingdao starfish disaster outbreak season in 2006 and 2007, the starfish outbreak was limited to the vicinity of the breeding area, and the starfish population size in other nearby sea areas has been maintained at a normal level.
This view believes that large-scale shellfish farming has lowered the threshold for outbreaks of starfish flooding.
Is there a way to eradicate or reduce the disaster of starfish flooding?
Is it feasible to eat?
This has been proven completely unworkable by countless examples.
In response to a netizen’s suggestion of "letting food to eliminate starfish", experts reminded that the starfish people usually eat are actually its gonads, which are slightly toxic.
Some people will have a tingling sensation in their mouths after eating, so it is recommended to eat less.
People who are weak and sick are best not to consume it.
Some people also mentioned crayfish (Procambarus clarkii). The same example is bullfrogs. Both crayfish and bullfrogs are very popular in street dining. Many domestic farmers make their fortunes by raising them, but this does not prevent them from continuing. In China's wild water bodies, they have become biological invasive species, and you cannot catch them all and eat them cleanly.
Then we will discuss how to reduce and contain the hazards of starfish explosions.
Because of the earliest impact of the starfish outbreak, Japan and the United States have gone the farthest in the field of preventing starfish outbreaks. But realistically speaking, they have no good way. The common method is to soak the ropes used for cultivating shellfish with lime. , Or sprinkle lime to kill.
Can you fish it all?
In our country, we mainly focus on fishing, but we usually wait for the disaster to break out before rushing to start, and the cost is huge.
For example, after the outbreak of the spiny barking disaster in Qingdao, farmers actively carried out self-rescue. There were more and more fishing boats fishing for starfish, but they were always unable to catch them.
Starfish caught ashore can still be sold, and the price of a large individual can reach 4 yuan per catty, but the cost of fishing has reached 3 yuan per catty, and as more and more sea stars are harvested, purchase Prices will definitely fall further, and a loss is an inevitable outcome, not to mention using the money earned by fishing starfish to compensate for the loss of shellfish.
Root cause: the imbalance of the marine ecosystem
Whether the sea star has a high reproduction rate or a large appetite, in fact, it will not cause a catastrophe. It was originally restrained by the layers of natural balance, but it is only a not unique link in the marine benthic ecological chain.
The root cause of the starfish outbreak is the imbalance of the marine ecosystem, which is the final result of the accumulation of many ecological crises.
If this deterioration of the environment is not addressed from the root cause, even if the starfish problem can be resolved, other potential hazards will always erupt.
Chengdu Commercial Daily-Red Star News Reporter Wang Tuo
Comprehensive CCTV News Report