Environmental Biology of Fishes

, Volume 88, Issue 4, pp 349–359

Utility of mesohabitat features for determining habitat associations of subadult sharks in Georgia’s estuaries

Article

DOI: 10.1007/s10641-010-9648-3

Cite this article as:
Belcher, C.N. & Jennings, C.A. Environ Biol Fish (2010) 88: 349. doi:10.1007/s10641-010-9648-3

Abstract

We examined the affects of selected water quality variables on the presence of subadult sharks in six of nine Georgia estuaries. During 231 longline sets, we captured 415 individuals representing nine species. Atlantic sharpnose shark (Rhizoprionodon terranovae), bonnethead (Sphyrna tiburo), blacktip shark (Carcharhinus limbatus) and sandbar shark (C. plumbeus) comprised 96.1% of the catch. Canonical correlation analysis (CCA) was used to assess environmental influences on the assemblage of the four common species. Results of the CCA indicated Bonnethead Shark and Sandbar Shark were correlated with each other and with a subset of environmental variables. When the species occurred singly, depth was the defining environmental variable; whereas, when the two co-occurred, dissolved oxygen and salinity were the defining variables. Discriminant analyses (DA) were used to assess environmental influences on individual species. Results of the discriminant analyses supported the general CCA findings that the presence of bonnethead and sandbar shark were the only two species that correlated with environmental variables. In addition to depth and dissolved oxygen, turbidity influenced the presence of sandbar shark. The presence of bonnethead shark was influenced primarily by salinity and turbidity. Significant relationships existed for both the CCA and DA analyses; however, environmental variables accounted for <16% of the total variation in each. Compared to the environmental variables we measured, macrohabitat features (e.g., substrate type), prey availability, and susceptibility to predation may have stronger influences on the presence and distribution of subadult shark species among sites.

Keywords

Essential fish habitat Subadult sharks Canonical correlation analysis Discriminant analysis 

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Marine Fisheries Section, Coastal Resources DivisionGeorgia Department of Natural ResourcesBrunswickUSA
  2. 2.U.S. Geological Survey, Georgia Cooperative Fish and Wildlife Research Unit, D.B. Warnell School of Forestry and Natural ResourcesUniversity of GeorgiaAthensUSA

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