Molecular detection of six viral pathogens from Australian wild sourced giant black tiger shrimp (Penaeus monodon) broodstock

Abstract

Disease presents a considerable challenge to the sustainability and development of global shrimp aquaculture. The Australian black tiger shrimp (Penaeus monodon) aquaculture industry is heavily reliant on wild-sourced broodstock for seedstock production, representing a large and under evaluated biosecurity risk. Currently, there is a paucity of quantitative, large-scale data detailing the extent of pathogenic agents in wild-sourced P. monodon broodstock. This study presents a comprehensive investigation of the presence and level of detection of endemic pathogen targets in wild-sourced P. monodon broodstock collected from the two primary sources of supply for the Australian shrimp aquaculture industry using quantitative polymerase chain reaction (qPCR). Broodstock pleopod samples (N = 7472) were analysed by TaqMan qPCR for the detection of six viral pathogens. In total, 44.9% of wild-sourced broodstock were positive for the detection of at least one pathogen target. White spot syndrome virus and yellow head virus-1 were not detected in any sample. Infectious hypodermal haematopoietic necrosis virus (30%) and gill-associated virus (28.1%) were the most prevalent pathogen targets detected. Whenzhou (syn. Wenzhou) shrimp virus-2 and yellow head virus-7 were each cumulatively detected in less than 3% of broodstock samples. Geographic source, sex and year of collection of broodstock significantly influenced prevalence of detection. The current study will be valuable to the Australian shrimp aquaculture industry to improve understanding of the presence of pathogens in wild-sourced broodstock, along with informing management decisions related to wild broodstock collection and associated biosecurity practices.