[Smart Farmers] Wild carp are also endangered! Wild forms of aquatic species are under threat

Editor’s Note:

The report of the 20th CPC National Congress emphasized that "we should consolidate the foundation of food security in all aspects" and "implement major biodiversity protection projects". What is the intrinsic connection between building a strong agricultural country and agricultural biodiversity? How to balance food security and sustainable agricultural development? What is the current status of agricultural biodiversity in my country? How to protect agricultural biodiversity? "Five grains and six livestock" and "one meal and one vegetable" are all topics we care about. Science Popularization China Smart Farmers has launched a series of popular science articles. Welcome to follow.

Biodiversity is a broad concept that describes the diversity of nature. It includes all animal, plant and microbial species on the earth and the genes they possess, as well as the ecological processes and all ecosystems they form.

Biodiversity includes three levels: genetic diversity, species diversity and ecosystem diversity. It is the result of billions of years of development and evolution of life on Earth and is the material basis for human survival.

Today's topic is fish, which refers to aquatic organisms including fish, shrimp, crabs, and shellfish. There are currently 22,396 species and subspecies of fish in the world, belonging to 4 classes, 57 orders, 479 families, and 3,848 genera. Only a small part of them have been studied and used by humans, that is, caught, domesticated, and cultivated for food or other purposes. Many species have become extinct before scientists have time to discover and name them.

Among the fish we eat, how many are wild? How many are farmed? This question is often difficult to answer for the following reasons: First, technology is advancing. Some fish that could not be farmed before can now be farmed, especially some marine fish. Second, the species and resource conditions in different places are different. Some fish resources have declined here, and they need to be farmed to meet market demand. Maybe the resources of this fish are abundant in other countries or regions, so the fish in their markets are wild caught.

However, according to the data from the Food and Agriculture Organization of the United Nations, a total of 554 species were reported as farmed in 2016. There are also some minor differences in the data, saying that from 1950 when the FAO began recording to 2016, a total of 598 species were farmed. So, are there 44 species that no longer need to be artificially bred, or have disappeared, or is it waiting for scientists to further study. The total number of farmed species reported in 2016 includes 369 finfish (including 5 hybrids), 109 mollusks, 64 crustaceans, 7 amphibians and reptiles (not including alligators, caimans or crocodiles), 9 other aquatic invertebrates and 40 aquatic algae.

It is important to note that these figures do not include species known or unknown to FAO, produced through research, cultured as live feed in aquaculture hatcheries, or ornamental species produced in captivity.

From 2006 to 2016, the total number of commercially farmed species or species items recorded by FAO increased by 26.7%, from 472 in 2006 to 598 in 2016. Moreover, the data reported by countries to FAO are out of sync with the actual rate of diversification of aquaculture species. Many single species items recorded in official statistics of many countries are actually composed of multiple species, sometimes hybrids.

Biodiversity also affects the diversity of farmed species, and therefore, we can eat a variety of delicious aquatic products. People who are not in the industry may not necessarily understand the importance of aquaculture. For ordinary people like us, what we care about most is whether there are fish to eat? What kind of fish to eat? Is it delicious? As for the importance of the healthy development of aquaculture to ensuring food security, protecting the ecological environment and biodiversity, providing employment and rural revitalization, perhaps few people know much about it.

According to FAO statistics, global aquaculture production hit a record high of 122.6 million tonnes in 2020, with a total value of US$281.5 billion. Aquatic animals accounted for 87.5 million tonnes, making a significant contribution to providing food and nutrition for the world's growing population.

According to FAO's Fisheries and Aquaculture Outlook 2030, production, consumption and trade are expected to continue to grow in the future. The total production of aquatic animals is expected to reach 202 million tons in 2030, mainly due to the continued growth of aquaculture.

In 2020, aquaculture contributed 49.2% of global aquatic animal production, a record high. The huge potential of aquaculture is obvious to all the world, but the growth must be sustainable, which is also the consensus of the fishing industry in various countries. Experts believe that the increase in the number of species may be a major reason for the rapid growth of aquaculture production. However, according to statistics, the types of farmed aquatic animals are very diverse, but the aquaculture production of food fish is dominated by a few "major" species, especially grass carp farmed inland and Atlantic salmon farmed in the ocean.

We all know that any livestock and poultry are domesticated from the wild, and aquaculture species are no exception. An international research report states that unlike the terrestrial agricultural industry, although the wild types of some aquatic species are under threat, especially due to the invasion of farmed and non-native genotypes, the wild relatives of all farmed aquatic species can still be found in nature. This natural reserve of genetic diversity not only supports capture fisheries and helps species adapt to human and natural impacts, but also provides a source of individuals and genes for aquaculture, so that they will not be wiped out, which is a bit smug.

However, a piece of news last year said that the carp’s endangered status was the same as that of the giant panda, which surprised people!

Carp pictures from the Internet

Carp is the earliest breed in my country's history. It belongs to a very large family. The highest classification is Cypriniformes, which consists of about 280 genera and more than 2,700 species. It is the most widely distributed freshwater fish in the world today. Its traces can be found almost everywhere on the earth. This does not include some new species that are constantly being discovered and improved. How can the endangered level of carp be the same as that of giant panda?

After careful investigation, it turned out to be true! Because the genes of wild carp populations have been continuously polluted in recent years. First, a large number of artificially bred carp have escaped into wild waters. Second, carp is the main species for release. Some people do not understand the scientific way of releasing them into wild waters and mate with wild carp, resulting in impure genes in wild carp populations and endangering the genetic diversity of wild carp populations.

As early as December 12, 2007, my country included wild carp in the "List of China's National Key Protected Economic Aquatic Animal and Plant Resources (First Batch)". In the "Red List of Endangered Species of the World Conservation Union" (IUCN 2008 ver3.1), carp also became a vulnerable (VU) species.

my country has always been a world leader in the breeding technology and production of carp fish. Especially with the rapid development of bioengineering technology, artificial hybrid breeding has bred many new carp varieties with fast growth and good quality, such as Fengli, Heyuan carp, Furong carp, Jianli, Songpu mirror carp, Xiangyun carp, Yuxuan Yellow River carp, Ukraine scale carp, Songhe carp, etc., which have become popular delicacies. However, the wild population of carp is endangered. Not only carp, but also silver carp, one of the four major carps, is in the same situation and is also near threatened (NT).

Sustainable aquaculture development requires the support of biodiversity. While developing aquaculture, paying attention to and protecting the health of wild related species is the fundamental guarantee for resisting risks. Therefore, we must protect the ecosystem, reduce pollution, protect biodiversity and thus ensure social equity.

Produced by: Popular Science in China to Benefit Farmers

Producer: Guangming Online Science Department

Author: Liu Yadan, Research Fellow, National Chief Scientific Communication Expert, former Assistant Secretary-General of the Chinese Society of Fisheries, and Assistant Secretary-General of the China Rural Professional and Technical Association

Review expert: Pan Xiaofu, senior engineer, Kunming Institute of Zoology, Chinese Academy of Sciences

Planning: Wu Yuetong, Jiang Nan