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.

Shrimp black gill is an emerging disease caused by a parasitic ciliate, Hyalophysa lynni, that attacks gill tissue in white shrimp Litopenaeus setiferus and brown shrimp Farfantepenaeus aztecus and induces an immune response that produces melanized tissue in shrimp gills. This immune response causes necrosis and damage in shrimp gill tissue, which limits shrimp metabolic capability and can lead to high predation mortality among infected individuals. Shrimp black gill was first observed in the southeast Atlantic shrimp fishery in the United States, and this ciliate has been increasing in prevalence in shrimp populations of this region since 2000. The Gulf of Mexico, with its lucrative shrimp fishery and extended warmwater conditions during the year, is a potential region for H. lynni spread. White and brown shrimp were sampled from seven major bays along the Gulf coast of Texas from March to November 2019 and underwent PCR analysis to detect H. lynni presence in gill tissue. From March to November, 65% of the collected shrimp samples tested positive for H. lynni. Samples from all seven bays tested positive for H. lynni, with the upper-coast bays having a significantly higher disease prevalence than lower-coast bays. Both white and brown shrimp samples tested positive for H. lynni; however, white shrimp samples had a significantly higher disease prevalence. Overall, disease prevalence showed a temporal pattern of low prevalence in the spring, peaking during the late fall. Generalized additive mixed models detected a high water temperature and a salinity level of 30‰ or less as significant contributors to high disease prevalence. This study validates the commonality of H. lynni presence in the western Gulf of Mexico, serves as a baseline for future shrimp black gill sampling efforts in this region, and contributes to the understanding and management of potential disease threats to the Texas shrimp fishery.

White spot syndrome virus (WSSV) is a virulent disease that disrupts shrimp farm operations throughout the world. While the United States has had only limited outbreaks of WSSV within the past several decades, it is important to ensure that this disease does not infect wild penaeid shrimp populations. In Texas, there is a potential for WSSV to spread to wild penaeid populations in the Gulf of Mexico via infected imported nonnative bait shrimp, imported broodstock, or wild crustacean hosts. Due to these potential threats, the Texas Parks and Wildlife Coastal Fisheries Division monitored WSSV in wild brown shrimp Farfantepenaeus aztecus and white shrimp Litopenaeus setiferus from seven major bay systems along the Texas coast during 2019. While no positive samples were detected from the collected shrimp, a power analysis illustrated a potential for low‐level WSSV prevalence within Texas shrimp populations that would not be detectable by this monitoring survey. Overall, WSSV does not appear to be a major threat in the Texas region of the Gulf of Mexico, but continual observation and monitoring of wild penaeid shrimp is necessary to protect this resource from future WSSV outbreaks.

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.