The Pliocene Elizabethtown otolith assemblage (Bladen County, North Carolina, USA) with indications of a primary fish nursery area

ABSTRACT

Bulk sampling of Pliocene (2.5–3.1 Ma, Piacenzian) beds at the Elizabethtown locality (Bladen County, North Carolina) produced 745 teleostean otoliths (17 taxa, representing extant fish off the U.S. Atlantic coast). Sciaenids dominate the assemblage (8 taxa; 44.4% of the total) and account for an extremely large percentage of total specimens (93.2%). The number of species (richness) at Elizabethtown is relatively small, and percentage abundance indicates a very large unevenness with Micropogonias undulatus and Leiostomus aff. L. xanthurus (91.4% of the specimens). Otolith assemblages from Elizabethtown and Lee Creek Mine, one of the most extensively studied North Carolina Pliocene sites, were compared. Assemblages were extremely dissimilar (percentage similarity measurement of 3.3%). Modern distributions of M. undulatus and L. aff. L. xanthurus are very strong indicators of shallow, soft bottom estuarine creeks and bays. The preponderance of juvenile M. undulatus (99.5% represent 1-year-old or less) is a strong indicator for a primary nursery area. This specialised habitat explains the dominance of juvenile Atlantic croakers and spots, the high percentage of fishes distributed in freshwater, brackish, and marine environments, and the paucity of marine-only species. The specialised habitat indicated at Elizabethtown would also account for the pronounced difference between the Elizabethtown and Lee Creek otolith assemblages.

KEYWORDS:

• Sciaenidae
• Atlantic Coastal Plain
• Micropogonias undulatus
• Leiostomus aff. L. xanthurus

Acknowledgments

Don Clements, Research Associate at the North Carolina Museum of Natural Sciences (Raleigh, North Carolina), was instrumental in initiating the investigation of the Elizabethtown locality by the authors. This study would not have been possible except for the foresight of K. Shannon to collect bulk samples in the aragonitic shell-bed layers (collecting is no longer possible at the site). L. Campbell (Professor Emeritus of Geology, University of South Carolina Upstate) provided very useful information and insight on the site’s stratigraphy. K. A. Johnson (National Marine Fisheries Service, Southeast Fisheries Science Center, Pascagoula, Mississippi), R. Taylor (formerly of the Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, St. Petersburg, Florida), and J. R. Hendon (Center for Fisheries Research and Development, Gulf Coast Research Laboratory, University of Southern Mississippi, Ocean Springs, Mississippi) generously provided Recent fishes and otoliths. D. Nolf (Institut Royal des Sciences Naturelles de Belgique, Brussels, Belgium) also supplied Recent and fossil otolith specimens and assisted in numerous ways. W. Schwarzhans (Natural History Museum of Denmark, Zoological Museum, Copenhagen, Denmark) made valuable suggestions regarding the identity and taxonomy of otoliths. P. Weaver, Collections Manager of Geology and Paleontology at the North Carolina Museum of Natural Sciences, aided in having the otoliths reposited. D. Bell (the University of Louisiana at Monroe Museum of Natural History) prepared the plate.

Disclosure statement

No potential conflict of interest was reported by the authors.