Multi-Year Environmental Trends of Shrimp Black Gill (Hyalophysa lynni) Prevalence in Texas Gulf Coast Shrimp Populations

Shrimp Black Gill, caused by the apostome ciliate Hyalophysa lynni, is an emerging disease impacting penaeid shrimp populations along the southeast Atlantic Coast and the Gulf of Mexico (GOM). Changing annual environmental conditions may drive infection levels of this parasitic ciliate in these populations, which comprise one of the largest fisheries in the United States. Hyalophysa lynni is established on the Texas Gulf Coast, and prevalence of this parasite has a strong seasonal and spatial trend, likely linked with high temperature and a wide range of estuarine salinities. Texas Parks and Wildlife Department monitored shrimp black gill in 2 penaeid shrimp species, Litopenaeus setiferus and Farfantepenaeus aztecus in 2019, with the aim of observing trends in prevalence along spatial and temporal scales. Hyalophysa lynni was found in all 7 bay systems throughout the study period, and this study is a continuation of that monitoring effort, adding 2 years of data collection (2020 and 2021) to prior research. Throughout the entire sampling period (2019–2021) and coastwide, H. lynni was found in 66% of all shrimp samples collected, although prevalence varied annually. Boosted regression tree modeling indicated that low salinity, high temperature, and time of year (late spring through fall) had a significant relationship with H. lynni prevalence in shrimp along the Texas Gulf Coast. Shrimp Black Gill is likely to continue to be present in GOM shrimp populations, and annual precipitation events and increased water temperatures may amplify the population morbidity within any given year

Penaeid Shrimp in Chesapeake Bay: Population Growth and Black Gill Disease Syndrome

Since 1991, the number of penaeid shrimp occurring in Virginia waters of Chesapeake Bay has steadily increased, prompting an interest in developing a fishery. Although development of a shrimp fishery in the Chesapeake Bay region could bring economic benefits, the fishery may be hampered by the presence of a disease syndrome known as shrimp black gill (sBG). The objectives of our study were to (1) describe the spatial distribution and abundance patterns of shrimp in Chesapeake Bay, (2) relate relative abundance of shrimp to habitat characteristics, and (3) determine the presence and seasonality of sBG to better understand disease dynamics in the region. Subadult penaeid shrimp were collected monthly from Virginia waters by trawl from 1991 to 2017, and individuals were identified to species and counted. White shrimp Litopenaeus setiferus were the most numerous species captured, followed by brown shrimp Farfantepenaeus aztecus and pink shrimp F. duorarum. Shrimp were captured primarily from July to December. White shrimp were the only species that exhibited visible signs of sBG, which was first observed in October 2016 (13.4% prevalence); the condition continued into November and recurred the following year. Shrimp with visible signs of gill disease were examined by microscopy, histology, and PCR assay and were diagnosed with infections of a histophagous apostome ciliate, presumably Hyalophysa lynni. Any impacts of sBG on shrimp survival or marketability should be considered in fishery management plans to ensure sustainability of the resource