Distribution and microhabitat use by flatfishes in a Louisiana estuary |
| |
Authors: | Robert L Allen Donald M Baltz |
| |
Institution: | (1) Coastal Fisheries Institute, USA;(2) Department of Oceanography and Coastal Sciences, Louisiana State University, Baton Rouge, LA, 70803-7503, U.S.A |
| |
Abstract: | We used a 1 m beam trawl to characterize microhabitat use of flatfishes in monthly samples collected in Barataria Bay, Louisiana.
Six strata were established along a salinity gradient from the nearshore zone along the Gulf of Mexico to approximately 30
km inland. Randomized sampling within strata characterized flatfish distributions and environmental conditions throughout
the bay. Microhabitats were characterized by salinity, temperature, dissolved oxygen, depth, distance from shore, and substrate
type. In 594 short-duration, beam-trawl samples collected from October 1992 through September 1994, we identified seven flatfish
species from 7046 specimens, most of which were juveniles. Four species accounted for 98.3% of all flatfishes. The two most
abundant, offshore tonguefish and bay whiff, were euryhaline and widely distributed over the salinity gradient; however, offshore
tonguefish were concentrated in the lowermost stratum where bay whiff were uncommon. The third species, fringed flounder,
was more abundant in middle and lower bay strata at higher salinities. The fourth species, blackcheek tonguefish, was most
common in middle and upper bay strata and declined in abundance in coastal strata. A rotated factor analysis resolved six
environmental variables into three major axes that explained 69 percent of the variance and were characterized as seasonal,
depth-distance, and substrate-salinity axes. Separation of species and life history intervals in three-dimensional factor
space reflected temporal and spatial segregation. Within the four common flatfishes, 14 of 24 variable comparisons showed
clear ontogenetic trends in which at least two size-class means differed significantly. Among the common species, temporal
differences were reflected by mean temperatures and dissolved oxygen concentrations and spatial differences were reflected
by other environmental variables, including depth, distance, substrate, and salinity.
This revised version was published online in July 2006 with corrections to the Cover Date. |
| |
Keywords: | juvenile flatfish nursery habitat ecological segregation Achirus lineatus Citharichthys spilopterus Etropus crossotus Paralichthys lethostigma Symphurus plagiusa Symphurus civitatium Trinectes maculatus |
本文献已被 SpringerLink 等数据库收录! |
|