Age and growth of endangered smalltooth sawfish (Pristis pectinata) verified with LA-ICP-MS analysis of vertebrae.
Endangered smalltooth sawfish (Pristis pectinata) were opportunistically sampled in south Florida and aged by counting opaque bands in sectioned vertebrae (n=15). Small sample size precluded traditional age verification, but fish collected in spring and summer had translucent vertebrae margins, while fish collected in winter had opaque margins. Trends in Sr:Ca measured across vertebrae with laser ablation-inductively coupled plasma-mass spectrometry corresponded well to annual salinity trends observed in sawfish estuarine nursery habitats in south Florida, thus serve as a chemical marker verifying annual formation of opaque bands. Based on that finding and assumptions about mean birth date and timing of opaque band formation, estimated age ranged from 0.4 y for a 0.60 m total length (TL) male to 14.0 y for a 4.35 m TL female. Von Bertalanffy growth parameters computed from size at age data were 4.48 m for L(∞), 0.219 y(-1)for k, and -0.81 y for t(0). Results of this study have important implications for sawfish conservation as well as for inferring habitat residency of euryhaline elasmobranchs via chemical analysis of vertebrae.
Department of Biology, University of West Florida, Pensacola, Florida, USA. rachel.scharer@MyFWC.com
Rachel M
RM
Scharer
William F
WF
Patterson
John K
JK
Carlson
Gregg R
GR
Poulakis
D000375:Aging / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D056727:Endangered Species; D063366:Estuaries; D005260:Female; D005431:Florida; D005843:Geography; D007834:Lasers; D008297:Male; D013058:Mass Spectrometry / Q000379:methods*; D010758:Phosphorus / Q000378:metabolism; D012860:Skates, Fish / Q000254:growth & development*; D013054:Spectrophotometry, Atomic / Q000379:methods*; D013131:Spine / Q000033:anatomy & histology / Q000254:growth & development*; D013324:Strontium / Q000378:metabolism
D010758:Phosphorus; D002118:Calcium; D013324:Strontium