World Aquaculture Magazine - June 2020

28 JUNE 2020 • WORLD AQUACULTURE • WWW.WA S.ORG mesticated shrimp stocks repro- duced in closed maturation sys- tems (Fig. 2). Two disease crises in 1999 drove the necessity for such a drastic change in the way the industry operated: theWSSV epidemic that swept through the Americas and the SlowGrowth Syndrome that made culturing black tiger shrimp unprofitable. There were problems in the early history of the adoption of domesticated shrimp by the industry and the move to SPF Pacific white shrimp in Asia. Adoption of SPF Pacific white shrimp in Asia lifted world production from one million t to three million t in ten years. Domestication of shrimp also provided the platform to increase the efficiency of shrimp production that resulted in increased volumes of shrimp at lower costs to consumers. It disrupted the shrimp industry and allowed application of genetic selection to domesticated stocks. Progress in shrimp breeding is generating more efficient shrimp for culture. Newly developed and evolving molecular technologies will provide the basis for the next big disruption in the shrimp industry. CP breeds shrimp to maximize diversity, which requires large breeding populations. CPF maintains over 3000 families/year. There are three independent breeding programs at three nucleus breeding sites. Selective genetics will result in inbreeding. Inbreeding effects on survival from nauplii to PL12 is very slight but inbreeding effects on shrimp disease challenge survival is significant. The maximum allow- able inbreeding needs to be determined. No fresh feeds are used in broodstock maturation and all algae are laboratory-grown. Individual tanks are used for family rearing. Brood- stock grow-out uses zero water exchange. Broodstock are grown from PL to broodstock in 170 days in a multiplication center. Nucleus and broodstock multipliers are under continuous disease surveillance, with 20,000 PCR tests per year. CPF has a shrimp disease challenge center. CPF uses indexing to breed for multiple traits. Indexing has evolved from growth and TSV resistance from 2004-2007 to growth, WSSV-resistance and robustness as current selection criteria. There is no negative correlation between growth and disease tolerance and there has been significant progress in breeding for TSV tolerance and AHPNS tolerance. Introduction Shrimp farming is the world’s most valuable aquaculture industry. Over 85 percent of global production is derived from domesticated stocks of Pacific white shrimp Letopenaeus vannamei . Global production dominance by Pacific white shrimp only started in the 1990s. Previously, the black tiger shrimp Penaeus monodon dominated global production. In the mid-1990s, global farmed shrimp production was 700,000 t per year with a total crop value of about $3.5 billion and Pacific white shrimp only contributed about 5 percent of global shrimp production. This six-fold increase in industry production and value resulted from the domestication, breeding and widespread use of Pacific white shrimp. The cumulative value added to the shrimp industry crop value from the introduction of Pacific white shrimp to Asia is about $225 billion. This industry transformation was driven by Pacific white shrimp’s lower production costs, reduced disease risks derived from their specific pathogen free (SPF) status, advancing domestication, and the species’ natural growth traits. The biggest opportunity to lower costs in shrimp farming is through continual advanced breeding with high performance genetics. Selective breeding of Pacific white shrimp is thus of vital concern for the industry’s continued profitability and sustainability. I invited colleagues working on shrimp breeding and genetics to participate in a Special Session on the topic. The session was held at Aquaculture America 2020 in Honolulu, HI in February 2020 (Fig. 1). This article provides a synopsis of the presentations made in that session. The Importance of Shrimp Breeding in Evolving the Modern Shrimp Industry Robins McIntosh Prior to 1999, world shrimp production was stagnant, with many problems caused by known diseases and unknown syndromes. Prior to 1999, early work on domestication and shrimp maturation by the Oceanic Institute provided the basis for an industry in crisis to move from producing post-larvae fromwild-caught broodstock to using do- Shrimp Breeding and Genetics: A Special Session Synopsis Jim Wyban FIGURE 1. Shrimp Breeding and Genetics Special Session presenters (L to R): John Buchanan, Oscar Hennig, Shaun Moss, Robins MacIntosh, Melony Sellars, JimWyban, Robin Pearl, Ravi Yellanki, Kyle Martin. FIGURE 2. The shrimp farming industry switched from using wild shrimp stocks to domesticated shrimp stocks in 1999.