Size-related shifts in the habitat associations of young-of-the-year winter flounder (Pseudopleuronectes americanus): field observations and laboratory experiments with sediments and prey.
Field surveys and laboratory studies were used to determine the role of substrata in habitat selection by young-of-the year winter flounder. A synoptic field survey of winter flounder and sediments in the Navesink River-Sandy Hook Bay estuarine system in New Jersey demonstrated that winter flounder distribution was related to sediment grain size. Analysis using a generalized additive model indicated that the probability of capturing 10-49 mm SL winter flounder was high on sediments with a mean grain diameter of </=0.5 mm, while fish 50-95 mm were least likely to be collected on fine sediments and most commonly on sediments with a grain-size near 1.0 mm. In the laboratory, sediment preferences and the burying ability of winter flounder (15-69 mm SL) were tested by exposing fish in 10-mm size groups to a choice of azoic sediments of different sediment grain sizes. Smaller individuals (<40 mm SL) preferred fine-grained sediments while larger individuals (>/=40 mm SL) preferred coarse-grained sediments. Burying ability increased with size and all flounders avoided sediments that prevented burial. Subsequent laboratory experiments revealed that the presence of live prey (Mya arenaria) can over-ride sediment choice by winter flounder (50-68 mm SL) indicating the complexity of interrelated factors in habitat choice.
Behavioral Ecology Branch, Northeast Fisheries Science Center, National Marine Fisheries Service, James J. Howard Marine Sciences Laboratory, 74 Magruder Road, 07732, Highlands, NJ, USA
B A.
BA
Phelan
J P.
JP
Manderson
A W.
AW
Stoner
A J.
AJ
Bejda