Research Article

Foraging by estuarine juveniles of two paralichthyid flounders: experimental analyses of the effects of light level, turbidity, and prey type

Published: 2022-8-25

Journal: Marine Ecology Progress Series

DOI: 10.3354/meps14102

Abstract

Juvenile summer flounderParalichthys dentatusand southern flounderP. lethostigmainhabit turbid salt marsh estuaries. Predation rates by juveniles (50-90 mm) were examined at 5 daytime light levels (6 × 1011to 2 × 1014quanta s-1cm-2) and in darkness and 4 turbidity levels (clear [≤1], 11, 20, and 40 NTU) at an intermediate light level. Both species fed equally well on benthopelagic mysid shrimp and benthic spionid polychaetes at all daytime light levels tested. However, predation on mysids was significantly reduced in the dark. Consumption of polychaetes was not reduced in the dark by either species, illustrating the effectiveness of non-visual foraging methods on benthic prey. Turbidity levels tested did not affect predation on either prey type by either flounder species. Locomotor behavior was examined at the same turbidity levels.P. lethostigmaspent more time swimming in the water column thanP. dentatusin lower turbidity (clear-20 NTU), and both species reduced swimming at 40 NTU. It appears that both species primarily use a benthic-oriented ambush foraging strategy under high turbidity conditions. This is a particularly pronounced switch in foraging style forP. lethostigma. Estuarine turbidity is increasing due to the impacts of climate change. When turbidity is elevated enough to eliminate light sufficient for visual feeding on mysids (between darkness and the lowest light level tested), feeding on this motile prey is negatively impacted for both species. Turbidity can thus alter foraging modes and types of prey consumed, affecting nursery habitat quality and the prey base supporting these young fishes.

Faculty Members

  • UA Howson - School of Marine Science and Policy, College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USAOffice of Renewable Energy Programs, Bureau of Ocean Energy Management, 45600 Woodland Rd, Sterling, VA 20166, USA
  • PA Grecay - Department of Biological Sciences, Richard A. Henson School of Science and Technology, Salisbury University, Salisbury, MD 21801, USA
  • PM Gaffney - School of Marine Science and Policy, College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA
  • TE Targett - School of Marine Science and Policy, College of Earth, Ocean, and Environment, University of Delaware, Lewes, DE 19958, USA

Themes

  • Impact of light levels on predation
  • Non-visual foraging strategies
  • Effect of turbidity on feeding strategies
  • Foraging behavior of juvenile flounders
  • Ecological implications of climate change on estuarine habitats

Categories

Download Article