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Environmental influences on the occurrence of coastal sharks in estuarine waters

2010; Inter-Research; Volume: 407; Linguagem: Inglês

10.3354/meps08546

1616-1599

John T. Froeschke, GW Stunz, ML Wildhaber,

Fish Ecology and Management Studies

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 407:279-292 (2010) - DOI: https://doi.org/10.3354/meps08546 Environmental influences on the occurrence of coastal sharks in estuarine waters John Froeschke1, Gregory W. Stunz1,*, Mark L. Wildhaber2 1Texas A&M University-Corpus Christi, Harte Research Institute for Gulf of Mexico Studies and Department of Life Sciences, 6300 Ocean Drive, Corpus Christi, Texas 78412-5869, USA 2US Geological Survey, Columbia Environmental Research Center, 4200 New Haven Road, Columbia, Missouri 65201, USA *Corresponding author. Email: greg.stunz@tamucc.edu ABSTRACT: Long-term fisheries independent gill net surveys conducted in Texas estuaries from 1975 to 2006 were used to develop spatially explicit estuarine habitat use models for 3 coastal shark species: bull shark Carcharhinus leucas, blacktip shark C. limbatus, and bonnethead shark Sphyrna tiburo. Relationships between environmental predictors and shark distribution were investigated using boosted regression trees (BRT). Bull shark was the most abundant species (n = 5800), followed by blacktip (n = 2094), and bonnethead sharks (n = 1793). Environmental conditions influenced distribution patterns of all species and relationships were nonlinear, multivariate, and interactive. Results showed very good model performance and suggested shark distribution is most closely linked to salinity, temperature, and proximity to tidal inlets. By interpolating the BRT models, maps of the probability of capture were produced using ordinary kriging. Results showed that the central region along the Texas coast contains the most important estuarine shark habitat. This area was characterized by warm temperatures, moderate salinities, and abundant tidal inlets. Bull sharks also extended into low salinity estuaries, while blacktip and bonnethead sharks were restricted to areas near tidal passes with moderate salinities. Juvenile sharks were frequently captured, suggesting the Texas coast may constitute important nursery areas for all 3 species. The development of these spatially explicit models allows for prioritization and conservation of areas in a region that has great potential for human disturbance and climate change impacts. These results provide new insight into the habitat requirements of coastal sharks in the northwestern Gulf of Mexico and practical information for managing this resource. KEY WORDS: Shark · Boosted regression trees · Essential fish habitat Full text in pdf format PreviousNextCite this article as: Froeschke J, Stunz GW, Wildhaber ML (2010) Environmental influences on the occurrence of coastal sharks in estuarine waters. Mar Ecol Prog Ser 407:279-292. https://doi.org/10.3354/meps08546 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 407. Online publication date: May 20, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.