RESUMEN
Large blooms of the dinoflagellate Karenia brevis cause annual harmful algal bloom events, or "red tides" on Florida's Gulf Coast. Each year, the Clinic for the Rehabilitation of Wildlife (CROW) is presented with hundreds of cases of aquatic birds that exhibit neurologic clinical signs due to brevetoxicosis. Double-crested cormorants (Phalacrocorax auratus) are the most common species seen, and typically present with a combination of ataxia, head tremors, knuckling, and/or lagophthalmos. Blood lactate levels are known to increase in mammals for a variety of reasons, including stress, hypoxia, sepsis, and trauma, but there is limited literature on blood lactate values in avian species. The objective of this study was to determine the prognostic value of blood lactate concentration on successful rehabilitation and release of birds presenting with clinical signs consistent with brevetoxicosis. Blood lactate levels were collected on intake, the morning after presentation and initial therapy, and prior to disposition (release or euthanasia) from 194 birds (including 98 cormorants) representing 17 species during the 2020-2021 red tide season. Overall, mean blood lactate at intake, the morning after intake, and predisposition was 2.9, 2.8, and 3.2 mmol/L, respectively, for released birds across all species (2.9, 2.9, and 3.2 mmol/L for released cormorants); 3.4, 3.4, and 6.5 mmol/L for birds that died (4.0, 3.5, and 7.9 mmol/L for cormorants that died); and 3.1, 3.5, and 4.7 mmol/L for birds that were euthanized (3.5, 4.7, and 4.9 mmol/L for cormorants that were euthanized). On average, birds that died or were euthanized had an elevated lactate at all time points as compared to those that were released, but these results were not statistically significant (P = 0.13). These results indicate that blood lactate levels do not appear to be useful as a prognostic indicator for successful release of birds, including double-crested cormorants, affected by brevetoxicosis.
Asunto(s)
Animales Salvajes , Ácido Láctico , Animales , Pronóstico , Aves , MamíferosRESUMEN
Willapa Bay (Washington State, USA) has been 1 of the rare intertidal locations where large-scale pesticide applications occur. Until recently, carbaryl was applied to control burrowing shrimp that decrease commercial oyster productivity. The bay is a critical habitat for green sturgeon (Acipenser medirostris), an anadromous species listed as threatened under the US Endangered Species Act. However, the hazard that carbaryl poses is unknown. Surrogate seawater-acclimated white sturgeon (A. transmontanus) were exposed to 0 µg L(-1) , 30 µg L(-1) , 100 µg L(-1) , 300 µg L(-1) , 1000 µg L(-1) , and 3000 µg L(-1) carbaryl for 6 h, and brain acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) activities were measured. Enzyme recovery was measured in an additional cohort exposed to 1000 µg L(-1) carbaryl for 6 h. Activity of AChE was reduced (p ≤ 0.001) at concentrations ≥ 100 µg L(-1) with recovery in the 1000 µg L(-1) cohort by 72 h. Surprisingly, BChE activity was greater than controls at concentrations ≥ 300 µg L(-1) (p > 0.05), a finding confirmed in additional fish exposed to 3000 µg L(-1) for 6 h (+30%, p < 0.001) with apparent recovery by 48 h. Plasma samples were collected from free-living green sturgeon before and 4 d to 5 d after application of carbaryl in Willapa Bay. Activity of BChE after application was reduced 28% (p < 0.001), indicating exposure to the pesticide. However, the lack of congruence between BChE and AChE activity in captive white sturgeon exposed to carbaryl indicates that further studies are needed to better understand the risk carbaryl exposure poses to green sturgeon. Environ Toxicol Chem 2016;35:2003-2015. © 2015 SETAC.
Asunto(s)
Butirilcolinesterasa/sangre , Carbaril/toxicidad , Crustáceos/efectos de los fármacos , Exposición a Riesgos Ambientales/análisis , Peces/sangre , Agua de Mar/química , Contaminantes Químicos del Agua/toxicidad , Acetilcolinesterasa/metabolismo , Animales , Biomarcadores/sangre , Encéfalo/efectos de los fármacos , Encéfalo/enzimología , Crustáceos/crecimiento & desarrollo , Relación Dosis-Respuesta a Droga , Ecosistema , Ostreidae/crecimiento & desarrollo , WashingtónRESUMEN
Carbaryl has been applied in Willapa Bay, Washington, for five decades to control burrowing shrimp (Neotrypaea californiensis and Upogebia pugettensis) on commercial oyster (Crassostrea gigas) beds. Concerns about effects on nontarget species, including fishes, have led to restrictions in use despite a lack of data on in situ exposure. We measured brain acetylcholinesterase (AChE) activity in adult Shiner perch (Cymatogaster aggregata) and juvenile Chinook salmon (Oncorhynchus tshawytscha) after operational applications. We hypothesized that exposure in Shiner perch would be greater than in juvenile Chinook salmon because of their greater site fidelity and benthic foraging. However, Shiner perch exhibited no statistically significant AChE inhibition. Enzyme activity was statistically decreased (≤14 %) in juvenile Chinook salmon after a second spray event; however, inhibition was less than that associated with overt effects and was similar to controls by 48 h after the spray. Diet analyses confirmed that Shiner perch were primarily feeding on benthic invertebrates and that juvenile Chinook salmon were feeding primarily within the water column. Composition of Shiner perch diets and amount of food consumed varied little among channels and time periods; however, Shiner perch on beds consumed more food 6 h after application than those at other time points and locations. There were no consistent differences in the diets of juvenile Chinook salmon within channels among time periods. Results suggest (1) that carbaryl applications pose little hazard to fish in the bay having habitat and dietary preferences similar to those of Shiner perch and juvenile Chinook salmon and (2) that quantification of direct exposure in the field is essential to adequately assess risk.
Asunto(s)
Acetilcolinesterasa/metabolismo , Encéfalo/metabolismo , Carbaril/toxicidad , Inhibidores de la Colinesterasa/toxicidad , Percas/metabolismo , Salmón/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Bahías/química , Encéfalo/efectos de los fármacos , Decápodos/crecimiento & desarrollo , Ecosistema , Monitoreo del Ambiente , Femenino , Masculino , WashingtónRESUMEN
Conflict between native amphibians and aquatic weed management in the Pacific Northwest is rarely recognized because most native stillwater-breeding amphibian species move upland during summer, when herbicide application to control weeds in aquatic habitats typically occurs. However, aquatic weed management may pose a risk for aquatic species present in wetlands through the summer, such as the Oregon spotted frog (OSF, Rana pretiosa), a state endangered species in Washington. Acute toxicity of herbicides used to control aquatic weeds tends to be low, but the direct effects of herbicide tank mixes on OSFs have remained unexamined. We exposed juvenile OSFs to tank mixes of the herbicide imazapyr, a surfactant, and a marker dye in a 96-h static-renewal test. The tank mix was chosen because of its low toxicity to fish and its effectiveness in aquatic weed control. Concentrations were those associated with low-volume (3.5 L/ha) and high-volume (7.0 L/ha) applications of imazapyr and a clean-water control. Following exposure, frogs were reared for two months in clean water to identify potential latent effects on growth. Endpoints evaluated included feeding behavior, growth, and body and liver condition indices. We recorded no mortalities and found no significant differences for any end point between the herbicide-exposed and clean-water control frogs. The results suggest that imazapyr use in wetland restoration poses a low risk of direct toxic effects on juvenile OSFs.