Misidentification of megalopae as a potential source of error in studies of population genetics and ecology of the blue crab Callinectes sapidus

Abstract

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 565:95-111 (2017) - DOI: https://doi.org/10.3354/meps12043 Misidentification of megalopae as a potential source of error in studies of population genetics and ecology of the blue crab Callinectes sapidus Timothy J. Sullivan*, Joseph E. Neigel Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70503, USA *Corresponding author: tsulli1988@gmail.com ABSTRACT: Inaccuracy in taxonomic identification is an unknown but potentially important source of error in studies of planktonic larval ecology and evolution. We address the misidentification of blue crab (Callinectes sapidus) megalopae (post-larvae) as a source of error in investigations of genetic variation and factors influencing settlement. Callinectes spp. megalopae were sampled monthly in spring and summer from the water column at 2 locations on the Texas (USA) coast and identified by 16S mitochondrial sequences. Most of the megalopae could be assigned to C. sapidus (62%), C. similis (36%), C. rathbunae (1.5%), or C. danae (0.12%), while 5 (0.8%) were ambiguously grouped with both C. similis and C. danae. Previously used morphological characters (rostrum length, carapace length, and their ratio) were not diagnostic. Species composition differed between locations and among monthly samples. A recurring seasonal pattern in species composition was discerned, with ~95% C. similis in April shifting to ~95% C. sapidus by May/June, and variable proportions in August. This pattern strongly parallels changes in allozyme allele frequencies previously reported for blue crab megalopae at the same locations. Models selected by the Akaike information criterion indicated lunar phase, temperature, salinity, storms, and wind stress components all affecting megalopal abundance. The importance and sign of these factors differed between species. Temperature, the most important factor for each species analyzed separately, was not important when species were combined. This study demonstrates that misidentification of larvae could create the appearance of temporal genetic variation, inflate estimates of abundance, and obscure factors influencing settlement. KEY WORDS: Larval ecology · Larval invertebrates · Larval settlement · Gulf of Mexico · Callinectes spp. · 16S rRNA gene · Barcoding · Blue crab Full text in pdf format Supplementary material PreviousNextCite this article as: Sullivan TJ, Neigel JE (2017) Misidentification of megalopae as a potential source of error in studies of population genetics and ecology of the blue crab Callinectes sapidus. Mar Ecol Prog Ser 565:95-111. https://doi.org/10.3354/meps12043 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 565. Online publication date: February 17, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.