Combined effects of flow speed and sub-lethal insecticide exposure on predator–prey interactions between the California killifish and an infaunal polychaete

• Published in: Ecotoxicology (London) 2019-01, Vol.28 (1), p.117-131
• Main Authors: Hayman, Nicholas T., Hentschel, Brian T., Renick, Violet C., Anderson, Todd W.
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal bites; Animals; Behavior; Biting; Brackishwater environment; Chlorpyrifos; Chlorpyrifos - adverse effects; Dose-Response Relationship, Drug; Earth and Environmental Science; Ecological effects; Ecological monitoring; Ecology; Ecotoxicology; Environment; Environmental Management; Enzyme inhibitors; Estuaries; Estuarine environments; Exposure; Feeding; Feeding Behavior - drug effects; Fish; Fluid dynamics; Fluid flow; Fluid mechanics; Flumes; Food Chain; Freshwater fishes; Fundulidae - physiology; Fundulus parvipinnis; Hydrodynamics; Insecticides; Insecticides - adverse effects; Laboratories; Pesticides; Polychaeta - drug effects; Polydora cornuta; Predation; Predator prey relations; Predator-prey interactions; Prey; Random Allocation; Sediments; Sediments (Geology); Toxicants; Water Movements; Water Pollutants, Chemical - adverse effects
• ISSN: 0963-9292; 1573-3017
• DOI: 10.1007/s10646-018-2005-6

Hydrodynamics and pollution affect estuarine populations, but their ecological effects have rarely been studied in combination. We conducted two laboratory experiments to quantify whether predator–prey interactions between California killifish, Fundulus parvipinnis , and the polychaete Polydora cornuta vary with flow speed and chlorpyrifos exposure. In one experiment, only F. parvipinnis was exposed to chlorpyrifos; in the other, only P. cornut a was exposed. The flume included a 300-cm 2 area of sediment with 24  P. cornuta in a central patch (98 cm 2 ). We videotaped groups of three killifish for 50 min at one of four flow speeds (6, 9, 12, or 15 cm/s) and recorded the proportion of bites directed at the prey patch. Unexposed killifish directed 70% of their bites at the prey patch at 6 cm/s, and prey-patch selection decreased as flow increased. Killifish exposed to chlorpyrifos directed 41% of their bites at the prey patch at 6 cm/s with reduced prey-patch selection relative to unexposed fish at 9 and 12 cm/s. At 15 cm/s, both exposed and unexposed fish displayed non-selective biting. Worms were videotaped to quantify their deposit- and suspension-feeding activities. Exposing worms to chlorpyrifos reduced total feeding activity by ~30%. Suspension feeding was more common at faster flow speeds, but the time worms spent suspension feeding relative to deposit feeding was unaffected by chlorpyrifos. No behavioral changes were noted in either species when the other was exposed to chlorpyrifos. This study highlights how hydrodynamic conditions can alter the relative importance of a toxicant’s effects on predator–prey interactions.