International Journal of Marine Science, 2025, Vol.15, No.2, 92-106 http://www.aquapublisher.com/index.php/ijms 96 the Cape of Good Hope to enter the Atlantic Ocean, and the Patagonian cold current at the southern end of South America also limits tropical shrimps to cross the sides of South America. Salt jump layers, hypoxic zones, etc. in the marine environment may also constitute invisible obstacles. 4 Artificial Introduction and Cross-Continental Transmission Path Analysis 4.1 Review of the introduction history in global shrimp aquaculture The global distribution pattern of shrimp species in large-scale introduction and breeding by humans has had a revolutionary impact. Since the second half of the 20th century, with the rise of aquaculture, major breeding shrimp species have been introduced to areas outside their origin for artificial breeding. The most typical one is the Whiteleg shrimp, which is native to the Pacific coast of the Americas. In the 1960s and 1970s, Southeast Asian countries began to develop local black tiger shrimp (spotted shrimp) farming, and at the same time tried to introduce different kinds of shrimp seedlings from neighboring countries to improve production. However, at that time, breeding technology was limited and the scale of transnational introduction was relatively small. The second stage was from the 1980s to 1990s. After the breakthrough in seedling cultivation and breeding technology, the tide of transcontinental introduction emerged. In 1988, China introduced the first Vannabin Prawn Prawn from Hawaii, USA, and successfully tried to raise it in Guangdong, kicking off the introduction of South American whitening prawns in Asia. In just over ten years, South American whitening prawns spread to the entire Asia-Pacific region through Taiwan, Thailand and other places. During the same period, India, Indonesia and others also introduced fine varieties of platylensis shrimp from their Asian neighbors to improve local germplasm (Tandel et al., 2017). Since the beginning of the 21st century, a global shrimp fry trade network has been formed, and some countries have begun to import shrimp fry from third countries in batches for breeding. For example, many Asian shrimp farmers choose to purchase SPF vannabean shrimp seedlings from the United States or Hawaii to reduce disease risk (Boyd and Jescovitch, 2020). Emerging breeders in Africa and the Middle East also purchase shrimp seedlings from Asia through international cooperation. 4.2 Global diffusion route for Litopenaeus vannamei 4.2.1 From the Eastern Pacific to Asia: the rise of seedling trade Whiteleg shrimp are native to the eastern Pacific coast (from Peru to Mexico coast), and before the 1980s, their breeding was basically limited to the Americas. The truly large-scale transcontinental spread began in the late 1980s and early 1990s. At that time, due to the continuous outbreak of viral diseases (such as leukoplakia) of prawns cultivated in Asia, it was urgent to find alternative varieties. In 1988, Chinese scientific researchers introduced South American white prawn parents from the United States for trial breeding for the first time and achieved success, which aroused strong interest from Asian countries. Subsequently, Taiwan introduced a batch of Pacific white shrimp from Hawaii in 1990, quickly realizing artificial seedling cultivation and promoting breeding. During the same period, Thailand also obtained seedlings from the United States and Taiwan, and Malaysia, Indonesia, Vietnam and others followed suit to introduce them. In just a few years, South American white prawn farming technology has spread in Asia. Around 1995, Whiteleg shrimp replaced local prawns and became the dominant breeding farm in Southeast Asia. Seedling trade played a key role in this process - early Asian shrimp seedlings relied heavily on pro-shrimps airlifted from Florida, Hawaii and other places in the United States, and then gradually achieved self-sufficiency in local seedlings (Moss et al., 2010). 4.2.2 Rapid expansion and genetic convergence of high-density breeding areas in Asia After the introduction of Whiteleg shrimp into Asia, countries quickly established high-density and intensive breeding systems, with rapid output growing, and problems such as genetic convergence and germplasm degradation have also occurred. From the late 1990s to the early 2000s, Thailand, mainland China, Vietnam and other places promoted the high-density breeding model of Whiteleg shrimp ponds on a large scale, with annual output hitting new highs. Taking China as an example, the total production of vannah shrimp has skyrocketed from thousands of tons in the early stages of introduction to millions of tons in the 2010s, and currently accounts for about two-thirds of global production. However, due to the relatively single source of the prawn germplasm introduced by most countries, and the lack of systematic breeding of good varieties during the breeding process,
RkJQdWJsaXNoZXIy MjQ4ODYzNA==