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

Abstract

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.