MOVEMENTS, FISHERY INTERACTIONS, AND UNUSUAL MORTALITIES OF BOTTLENOSE DOLPHINS by STEVE F. SHIPPEE B.S. University of West Florida, 1983 Professional Certificate in Natural Resource Management, University of California San Diego, 2001 A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Biology in the College of Sciences at the University of Central Florida Orlando, Florida Spring Term 2014 Major Professor: Graham A.J. Worthy © 2014 Steve F. Shippee ii ABSTRACT Bottlenose dolphins (Tursiops truncatus) inhabit coastal and estuarine habitats across the globe. Well-studied dolphin communities thrive in some peninsular Florida bays, but less is known about dolphins in the Florida panhandle where coastal development, storms, algal blooms, fishery interactions, and catastrophic pollution have severely impacted their populations. Dolphins can react to disturbance and environmental stressors by modifying their movements and habitat use, which may put them in jeopardy of conflict with humans. Fishery interaction (FI) plays an increasing role in contributing to dolphin mortalities. I investigated dolphin movements, habitat use, residency patterns, and frequency of FI with sport fishing. Dolphins were tracked using radio tags and archival data loggers to determine fine-scale swimming, daily travels, and foraging activity. Dolphin abundance, site fidelity, ranging, stranding mortality, and community structure was characterized at Choctawhatchee and Pensacola Bays in the Florida Panhandle via small boat surveying and photo-identification. Reported increases in dolphin interactions with sport anglers were assessed at deep sea reefs and coastal fishing piers near Destin, FL and Orange Beach, AL. Results from these studies yield insights into the ranging and foraging patterns of bottlenose dolphins, and increase our knowledge of them in the northern Gulf of Mexico. Dolphins were tagged with short-term Trac Pac tags (N=23) and bolt on radio-tags (N=5) during 1995-2007. Swim speeds averaged 1.6 m/s (±0.43 SD), which agreed with the predicted mean cost of transport. On average, 48% of their day was spent transiting between habitats. Swimming and activity rates did not vary significantly with time of day/night. Foraging and social interactions constituted 39% of their day. Increased foraging was detected by stomach iii temperature changes that revealed dolphins fed during daylight, but also at night with a peak starting just after sunset. Tagged dolphins exhibited behaviors suggesting ‘sleep’ during slow speed swimming, which represented 15% of their day on average. Dolphins made daily movements beyond their expected core area, heading up river tributaries, and to the open sea. Surveys in Choctawhatchee Bay began in 2006 and later expanded to include Pensacola Bay in 2010 following concern of dolphin mortalities in concert with the Deepwater Horizon spill and two extremely cold winters. Photo-identification revealed dolphins moved frequently between the bays. Of 655 individuals identified in 2010-11, 22% were seen during all seasons, with highest abundance in the fall. Resident dolphins showed site fidelity to specific areas (42%) or traveled between parts of the bays (58%). Three communities of dolphins were identified from stable isotope analysis and photo-id: 1) tidal inlet associated, 2) estuarine specific, and 3) river delta associated. Dolphins traveled over 70 km via the near-shore Gulf between the inlets, and through the inshore waterways. The findings suggest dolphin communities in these bays overlap and many dolphins had a high probability of oil exposure in 2010. I observed sport fishing trips to assess frequency and nature of FI over 28 months. FI was seen at 18% of fishing reef spots. Scavenging of discarded fish was seen most often, while depredation of catch occurred in 40% of FI observations. Of 103 dolphins identified on offshore reefs, 13% were encountered repeatedly. At coastal fishing piers, dolphins came within 100 m on 42% of visits, while FI was seen on 17% of visits. Most dolphins at the fishing piers were known inlet and estuarine residents, while offshore reef dolphins were never seen near the beach. This indicates that discrete communities are involved. Harmful interactions with dolphins on reefs and at fishing piers negatively affect these resident communities. Mitigation of FI is suggested by use of avoidance strategies, gear modifications, and improved fish release practices. iv To boldly go where no man has gone before… - Captain Kirk Two roads diverged in a wood, and I, I took the one less traveled by, And that has made all the difference. - Robert Frost v ACKNOWLEDGMENTS The projects I undertook were entirely dependent on assistance with tag design and application, radio tracking, field surveys, photo analysis, stranding response, and biopsy sampling. I especially thank Forrest Townsend and Frank Deckert (Trac Pac Inc); Randy Wells, Aaron Barleycorn, and Jason Allen (SDRP, Mote Marine Lab); Greg Bossart, Steve McCulloch, Marilyn Mazzoil, and Elizabeth Howells (Harbor Branch Marine Mammal Program); Jay Sweeney (Dolphin Quest); Aleta Hohn and Larry Hanson (NMFS Beaufort Lab); Monica Parries (UWF Pensacola), Christina Toms (UCF Biology) and Courtney Smith (USM Hattiesburg); Amanda Wilkerson, Stephanie Kadletz, Brittany Patrick, Deb Edwards, Cathy Holmes, Istvan Zsok, and Michelle Gonzales (ECWR); Blair Mase, Jenny Litz, Elizabeth Stratton, Lauren Noble, and Micah Brodsky, VMD (NMFS-SER); Sarah Kalinoski and Julia Terrell (CBA); Gary Parsons (Choctawhatchee Audubon); Capt. Jim Green (New Florida Girl American Spirit) and Capt. Troy Frady (Distraction Charters); and Capt. Cliff Atwell & Capt. Steve Wilson (Southern Star Dolphin Cruises). I owe my greatest debt to my parents, Margarete and Spencer Shippee for their inspiration in all things animal & aquatic since my early youth; and to my beloved Tara Kirby who kept me in fine mental health during the major part of this epic journey. The research work described here was made possible by grants from Florida’s Protect Wild Dolphins, Dolphin Quest Foundation, Sea World Busch Gardens Conservation Fund, Mississippi-Alabama Sea Grant Consortium, NOAA Prescott Grant Program, and The Gulf of Mexico Research Initiative through the Florida Institute of Oceanography. Sincere thanks to the “Four W’s”: advisor, Dr. Worthy, and committee members, Dr. Weishampel, Dr. Walters, and Dr. Wells for their expert guidance and suggestions in developing and completing this dissertation. vi TABLE OF CONTENTS LIST OF FIGURES ..................................................................................................................... xiii LIST OF TABLES ....................................................................................................................... xvi LIST OF ACRONYMS ............................................................................................................. xviii CHAPTER ONE: INTRODUCTION ............................................................................................ 1 Background ..................................................................................................................... 1 Residency, Site Fidelity, and Habitat Use................................................................... 2 Movements and Ranging ............................................................................................ 3 Swimming Speed and Daily Travels (Energetics) ...................................................... 4 Resting ........................................................................................................................ 4 Impacts of Provisioning by Humans and Fishery Interactions ................................... 5 Reproduction, Juvenile Survival, and Dispersal ......................................................... 5 Foraging Implications ................................................................................................. 6 Methodology and Approach ........................................................................................... 8 Radio and Satellite-Linked Tags ................................................................................. 8 Mark-Recapture Surveys .......................................................................................... 10 Remote Dart Biopsy Sampling and Stranded Animal Tissue Collection ................. 11 Preview of Work ........................................................................................................... 12 CHAPTER TWO: ARCHIVAL TAGS WITH STOMACH TEMPERATURE TELEMETRY FOR MEASURING FINE-SCALE TRAVEL AND FORAGING IN FREE RANGING BOTTLENOSE DOLPHINS ............................................................................................ 15 Introduction ................................................................................................................... 15 vii Methods ........................................................................................................................ 18 Health Assessments .................................................................................................. 18 Trac Pacs ................................................................................................................... 20 Archival Data Loggers .............................................................................................. 22 Stomach Temperature Pill and Data Logging ..........................................................