Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga

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 602:213-224 (2018) - DOI: https://doi.org/10.3354/meps12673 Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga Samuel C. Ginther*, Mark A. Steele California State University Northridge, Department of Biology, Northridge, CA 91330-8303, USA *Corresponding author: samuel.ginther@csun.edu ABSTRACT: Some invasive species have devastating ecological impacts on native species, whereas others have little effect. The macroalga Sargassum horneri recently invaded the waters of California (USA) and Mexico, and in some places has largely replaced an important native macroalga, the giant kelp Macrocystis pyrifera. To explore the potential impacts of the invasive alga on populations of an ecologically and economically important fish, the kelp bass Paralabrax clathratus, we tested whether recruitment of kelp bass onto macroalgae differed between the invasive S. horneri and native M. pyrifera. Field surveys by scuba divers on naturally occurring S. horneri and M. pyrifera at Santa Catalina Island revealed that kelp bass recruits were ~30 times more abundant on individual M. pyrifera than on individual S. horneri. To assess the cause of this pattern, we conducted a field experiment in which plots containing 3 treatments (M. pyrifera only, S. horneri only, and M. pyrifera and S. horneri together) were isolated over a sandy bottom, which limited post-settlement movement of recently settled kelp bass among macroalgae. Kelp bass recruitment was similar for the 2 treatments containing M. pyrifera, but no recruits were observed on S. horneri, regardless of whether the alga was alone or paired with M. pyrifera. Additionally, we found a strong spatial gradient in recruitment among the experimental plots that was explained by the abundance of larger, cannibalistic conspecifics. This study presents the first evidence that invasive S. horneri may negatively impact an important reef fish. KEY WORDS: Sargassum horneri · Macrocystis pyrifera · Kelp bass · Santa Catalina Island Full text in pdf format PreviousNextCite this article as: Ginther SC, Steele MA (2018) Limited recruitment of an ecologically and economically important fish, Paralabrax clathratus, to an invasive alga. Mar Ecol Prog Ser 602:213-224. https://doi.org/10.3354/meps12673 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 602. Online publication date: August 23, 2018 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2018 Inter-Research.