Assessing residency time and habitat use of juvenile smalltooth sawfish using acoustic monitoring in a nursery habitat

Ld Hollensead,Rd Grubbs,Jk Carlson,Dm Bethea

doi:10.3354/esr00919

Abstract

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 37:119-131 (2018) - DOI: https://doi.org/10.3354/esr00919 Theme Section: Biology and ecology of sawfishes Assessing residency time and habitat use of juvenile smalltooth sawfish using acoustic monitoring in a nursery habitat Lisa D. Hollensead1,4,*, R. Dean Grubbs1, John K. Carlson2, Dana M. Bethea3 1Florida State University Coastal Marine Laboratory, St. Teresa, FL 32358, USA 2NOAA NMFS Panama City Laboratory, Panama City, FL 32408, USA 3NOAA NMFS Southeast Regional Office, St. Petersburg, FL 33701, USA 4Present address: University of North Carolina Wilmington, Wilmington, NC 28403, USA *Corresponding author: ldh7520@uncw.edu ABSTRACT: Highly productive, protected habitats have been shown to serve as nurseries for many marine fishes. However, few studies quantitatively measure the biotic characteristics that often drive a habitat’s function as a nursery. We used a combination of passive acoustic monitoring and quantification of biotic attributes to assess nursery habitat use of juvenile smalltooth sawfish Pristis pectinata. Acoustic receivers were deployed within Everglades National Park to quantify residency, identify the timing of emigration, and detect migration of juvenile smalltooth sawfish. Benthic grain size and organic content along with mangrove prop root density and limb overhang were quantified throughout the array to test for relationships between habitat attributes and smalltooth sawfish presence. Results indicated that sawfish moved quickly through deep water, narrow creeks, and rivers between shallow tidally influenced bays. A stepwise regression analysis of detections per hour indicated that sawfish had an increased probability of being encountered in areas with high prop root density. Observed residency within the nursery ranged from days to several months with some overwintering, which has never previously been documented in Everglades National Park. Given the large amount of individual variability of movement within the study area, future studies of juvenile smalltooth sawfish habitat in Everglades National Park should strive to investigate the relationships between occurrence and other potential drivers of habitat use such as prey fish assemblage and relative flow at multiple spatiotemporal scales. KEY WORDS: Pristis pectinata · Nursery · Habitat use · Movement · Conservation · Management Full text in pdf format PreviousNextCite this article as: Hollensead LD, Grubbs RD, Carlson JK, Bethea DM (2018) Assessing residency time and habitat use of juvenile smalltooth sawfish using acoustic monitoring in a nursery habitat. Endang Species Res 37:119-131. https://doi.org/10.3354/esr00919 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 37. Online publication date: October 10, 2018 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2018 Inter-Research.

Highlights

Discrete coastal habitats that are highly productive, such as bays and estuaries, have been shown to serve as nursery areas for many marine fishes (Carlson & Straty 1981, Meyer et al 2000, Beck et al 2001), including elasmobranchs (Castro 1993, Holland et al 1993, Carlson et al 2008)
Coastal habitats, including backwater portions of estuaries, within southwest Florida from Charlotte Harbor to Florida Bay function as nursery habitat for the smalltooth sawfish Pristis pectinata, an elasmobranch listed as endangered under the US Endangered Species Act (ESA) in 2003 (Poulakis et al 2011, Hollensead et al 2016, National Marine Fisheries Service (NMFS) 2003)
We examined juvenile smalltooth sawfish movement within the backwater region of the northernmost portion of Everglades National Park (ENP)

Summary

Introduction

Discrete coastal habitats that are highly productive, such as bays and estuaries, have been shown to serve as nursery areas for many marine fishes (Carlson & Straty 1981, Meyer et al 2000, Beck et al 2001), including elasmobranchs (Castro 1993, Holland et al 1993, Carlson et al 2008). Coastal habitats, including backwater portions of estuaries, within southwest Florida from Charlotte Harbor to Florida Bay function as nursery habitat for the smalltooth sawfish Pristis pectinata, an elasmobranch listed as endangered under the US Endangered Species Act (ESA) in 2003 (Poulakis et al 2011, Hollensead et al 2016, NMFS 2003). This region has been designated under the ESA as critical habitat (NMFS 2009, Norton et al 2012). Rapid juvenile growth is typical of many batoids (Simpfendorfer et al 2008, Dale & Holland 2012), and in sawfish, may facilitate a rapid decrease in predation risk as potential predators such as bull sharks Carcharhinus leucas, lemon sharks Negaprion brevirostris, and American crocodiles Crocodylus acutus co-occur in these inshore areas (Wiley & Simpfendorfer 2007)

Methods

Results

Discussion

Conclusion