Effects of Sublethal Chlorpyrifos Exposure on Postlarval American Lobster ( Homarus americanus )

Abstract

The organophosphate pesticide chlorpyrifos has been introduced to the marine environment via adsorption to agricultural soil runoff or as spray drift. Chlorpyrifos affects the survival of some larval decapod crustaceans, but no data exist on the impacts to the American lobster, Homarus americanus. The purpose of the present study was to assess the levels at which chlorpyrifos affects the survival of postlarval H. americanus. Using acute saltwater exposures, the 24‐ and 48‐h median lethal concentrations were established for stage IV H. americanus (1.56 and 1.33 µg/L, respectively). Movement, acetylcholinesterase activity, intermoult period, specific growth rate, and moult increment were measured during exposure to sublethal concentrations. Movement patterns were assessed to establish a 48‐h median inhibition concentration for cessation of normal movement (0.66 µg/L). Acetylcholinesterase activity was found to be inhibited immediately post‐exposure to 0.50, 0.57, and 0.82 µg/L chlorpyrifos but could be recovered within a period (9–15 d) in clean seawater. Sublethal growth effects of increased intermoult period, decreased specific growth rate, and decreased moult increment were observed during exposure to an environmentally relevant concentration (0.82 µg/L). The present study suggests that H. americanus stage IV larvae were marginally less sensitive to chlorpyrifos compared with other decapods and that acute lethality of H. americanus postlarvae is not likely to occur with chlorpyrifos concentrations previously reported from aquatic environments. Environ Toxicol Chem 2019;38:1294–1301. © 2019 SETAC

Glyphosate Herbicide Induces Changes in the Growth Pattern and Somatic Indices of Crossbred Red Tilapia (O. niloticus × O. mossambicus)

“…These include the effect of the organophosphate pesticide fenitrothion on the behavioral alterations of European seabass Dicentrarchus labrax [ 51 ] or the effect of total toxic compounds in ponds on the reproductive capacity of the common toad Bufo bufo [ 52 ]. In some of the correlation studies, a nonlinear correlation is implied as seen in a study on the effect of chlorpyrifos on the specific growth rate of the American lobster ( Homarus americanus ) [ 53 ] or the effect of nitrite on the total feed intake and specific growth rate of Clarias gariepinus [ 54 ]. In this study, we attempt to correlate the effect of technical grade glyphosate to several toxicity parameters.…”

The stress–immunity axis in shellfish

“…While concentrations of these pesticides can be lethal in extreme cases, more often they accumulate within shellfish and lead to chronic idiopathy. For example, exposure of American lobsters (Homarus americanus) to environmentally relevant concentrations of chlorpyrifos, 0.5 -0.82 μg L -1 , led to the inhibition of acetylcholinesterase activity (within 24 -48 hours) and interfered with moulting and growth (Taylor et al, 2019). Malathion and endosulfan alone, and in combination, reduced survival of P. vannamei by <4% over 96 hours using concentrations at 1, 10 and 50% the LC50 for each pesticide (78 and 0.2 μg L -1 , respectively; Bautista-Covarrubias et al, 2020).…”

Evaluating non‐lethal and latent effects of the anti‐sea lice pesticide azamethiphos on larvae and adults of the American lobster ( Homarus americanus )

“…These concentrations represent what may be observed 60 m around a tarp or 6 m in a well boat treatment with azamethiphos (Ernst et al, 2014). Comparatively, similar studies with 3 h exposure trials revealed LC 50 values (± SE) for Stage I and Stage IV as 5.87 (±2.01) and 20.45 (±12.77) μg azamethiphos L −1 (Taylor et al, 2019). Parsons et al (2020) similarly found no significant difference between the immobilization or mortality response in the larvae of the European lobster ( Homarus gammarus ) following a 1 h exposure to azamethiphos followed by a 24 h recovery period (EC50s of 15.5 and 9.2 μg azamethiphos L −1 ).…”