Friends who have lived in Guangdong know that there are all kinds of strange fish in the river, some of which taste good, and some of which are even inedible! And these fish are not inland, in fact, they are not native fish in china, but foreign invasive fish!
It is not unfamiliar to us to mention biological invasion, referring to the phenomenon that "a certain organism has been naturally introduced from other places or artificially introduced into the wild and has caused certain harm to the local ecology." It can also be said that non-native species can be called alien species, and there are 7 species of exotic fish commonly found in Guangdong.
Tilapia: Tilapia is an invasive fish that was introduced from Vietnam in 1957 with the first Mozambican tilapia, more than half a century ago, and after several more introductions, they spread in the wild.
Scavengers: In order to clean up the garbage in the fish tank, scavengers entered our country in the 80s and 90s of the last century, and in just a few decades, they have flooded most of the southern region.
Pond mackerel: Pond mackerel was introduced from Egypt in 1981, and in 1982, Guangdong Freshwater Aquaculture Farm successfully bred and bred, and has since entered the streets. Around 2000, the night market was very popular, charcoal grilled catfish is a delicacy, the ingredient is pond catfish!
Mud carp: There are 2 species of invading mud carp, one is Thai carp and the other is wheat carp. The real name of the Thai carp is Lusta Nok, which was introduced from Thailand in 1978 so it was called the Thai carp. The original name of the Wheat Carp is The Wheat Ray Galactic Carp, which was introduced from India in 1982.
Green Sunfish: Native to the Americas, green sunfish have been introduced to Africa, South America, Asia and Europe, and were introduced in 1999 as ornamental and sport fishing fishing, where they spread out in the wild after entering wild waters.
Mosquito-eating fish: In 1924, the Philippine Institute of Medical Sciences donated a batch of mosquito-eating fish to Shanghai for trial breeding, and later after several introductions and large-scale releases, they have a large population in the waters.
Largemouth bass: native to Canada and the United States, Shenzhen, Huiyang, Foshan and other places in 1983 introduced largemouth bass seedlings, and in 1985 successively artificial breeding success. The propagated fry have been introduced to Jiangsu, Zhejiang, Shanghai, Shandong and other places in China for culture.
These 7 species of fish enter the country at different times and in different places, but the common point is that they have long been everywhere, and they have their traces in small street rivers, ponds and ditches, river reservoirs, etc., and they are very dense. Although they were introduced for different purposes, they were not intended to breed in the wild.
Each plant or animal has its own way of survival, in order to adapt to the environment, they have evolved a variety of organs, or have their own unique survival skills, so why can these alien species run amok in Guangdong? There are 7 reasons for this.
Abundant water resources: Guangdong has abundant precipitation, with an average annual precipitation of between 1300-2500 mm and abundant water resources. Such a large amount of precipitation, many rivers, which provides a suitable growth environment for exotic fish to grow slowly.
Suitable temperature: Guangdong Province belongs to the East Asian monsoon region, from north to south are central subtropical, South Asian tropical and tropical climate, the average temperature is 28-29 °, suitable for the growth of these fish, although there are occasional low temperature weather in winter, some fish that are not tolerant to low temperature are frozen to death, but in general, the impact on these fish is not large.
Not picky about food: these 7 species of fish, except for largemouth bass, are omnivorous, that is, what to eat, not picky feeding methods allow them to adapt to most of the environment, as long as the temperature is right, there is a water source, they can survive.
Can tolerate extreme environment: the so-called extreme environment refers to some polluted waters, we all know that although Guangdong is rich in water resources, but due to the development of the economy caused by serious pollution, and these fish have a very good ability to resist pollution, even if the water quality pollution can survive.
Fast growth rate: Although these fish have a large difference in appearance, they all have one of the biggest characteristics, that is, they grow fast. Because of the fast growth rate, it can obtain benefits in a short period of time in the case of breeding, so it is promoted as a cultured variety. Scavengers and mosquito-eating fish are more different, scavengers are to clean the fish tank, and mosquito-eating fish are to reduce the breeding of mosquitoes. It is equivalent to saying that each has its own use, but only after they are flooded do they know the harm.
Strong reproductive ability: These invasive fish are very reproducive and can form groups in the wild in a short period of time. For example: tilapia have the habit of protecting eggs after breeding, the survival rate of fish fry is greatly increased, and mosquito-eating fish are egg-born, and fry are directly produced without spawning!
No predators: The complete biological chain is that every creature can be countered, and these exotic fish have no natural enemies! Their growth cannot be inhibited, resulting in uncontrolled reproduction, and the number is increasing, the density is increasing, and even some of the scavengers, tilapia, and pond mackerels in some rivers have been flooded.
Abundant water resources, suitable temperatures, not picky about food, able to tolerate extreme environments, fast growth rate, strong reproductive ability, no natural enemies, these 7 reasons for these foreign fish can grow naturally, and the rate of reproduction is very fast. In fact, not only in Guangdong, Hainan, Fujian, Yunnan and other places, they can grow, and the density of population is very large.
So we can't help but wonder, where do the native fish go? The growth space in the water is limited, after these exotic fish enter the water to grow, can the native fish still grow? In fact, there is bitterness that cannot be said! Because the native fish can't compete with them, they have lost the battle, and the number is getting smaller and smaller! There are 7 reasons for this.
Slow growth rate: for example: crucian carp vs tilapia, crucian carp growth rate is very slow, in the wild state 3 years is difficult to weigh a pound, but tilapia 3 years can even reach several pounds, the difference is too big. For example: earth carp vs Tai carp, 2-year-old earth carp does not have a pound, but Thai carp easily weighs a few pounds! The slow growth rate makes native fish less competitive than exotic fish.
High water quality requirements: Crucian carp, grass carp, silver carp and other native fish have relatively high water quality requirements and cannot survive in slightly polluted waters, resulting in smaller and smaller populations. However, pond mackerel, tilapia, scavengers and other exotic fish, even if they survive in slightly polluted waters, are not affected, are very resistant to pollution, and can even grow in sewers.
There are many predators: Fish have predators unless you can stand at the top of the food chain, but these alien species have no predators! For example, the Thai carp is huge, and the Thai carp can even grow to dozens of pounds, and there is no natural enemy to threaten them when they become adults. For example, scavengers are exoskeleton fish, whether birds or carnivorous fish are difficult to swallow, even if forcibly swallowed, they may be pierced through the esophagus.
Meat quality is general: everyone knows that southerners do not eat carp, because the silt in the southern rivers is relatively thick, and carp has been rummaging in the silt for a long time to find food, so the meat has an earthy smell and few people eat it. However, tilapia, largemouth bass, and green sunfish have relatively good meat quality and a large number of people eating them, which also causes some native fish to be unpopular.
Low reproductive ability: strong reproductive ability, in order to form a population in a short period of time, although crucian carp, carp, silver carp, grass carp breed quickly, but relative to foreign fish is still a small witch. For example, after the tilapia spawns, it will wait until the eggs hatch and have the ability to survive independently before leaving the cubs. For example, mosquito-eating fish spawn several times a year, and the eggs hatch in the belly of the female fish, directly laying juveniles, which causes a high survival rate of fry. And in the river where there are mosquito-eating fish, native medaka is rare.
Slow growth rate, high requirements for water quality, more natural enemies, general meat quality, low reproductive capacity, which causes native fish to be less competitive, for foreign fish step by step, there is no power to fight back!
The commander of the bald fish summed up: It is not that the native fish are not strong enough, but the opponent is too perverted, after all, any fish that can survive is after thousands of years of efforts and has evolved step by step. When these exotic fish enter, they destroy the ecological environment and break the rules, thus being unscrupulous, resulting in fewer and fewer native fish.
Finally: these 7 species of fish, have long been in the "blacklist", even in the international is also a well-known invasive species, anglers do not release after catching, casually thrown into the trash can, or buried and disposed of. In addition to these, do not release foreign fish, especially predatory fish such as: alligator eel, alligator turtle, electric eel, etc. do not release, so as not to destroy the ecology.