Telemetry‐Based Mortality Estimates of Juvenile Spot in Two North Carolina Estuarine Creeks

Abstract

This thesis would not have been possible without the unconditional guidance, support and understanding from nothing short of a plethora of amazing people. First and foremost I would like to thank those in Michigan who donated their time, patience and knowledge and in doing so helped me successfully embark on my career as a fisheries scientist. Greg Kennedy, Jaquie Craig and Beth Stockdale showed me what it means to truly love your work. We were able to find something to laugh at every day (mostly ourselves) and I can't thank them enough for the continued support and camaraderie. Glenn Walker went above and beyond, helping me navigate the world of academia, temporarily inspiring me to love the field of cellular and molecular biology, and providing a great lunchtime listening ear. Laura Eidietis was instrumental in kick-starting my career during my undergraduate years at Eastern Michigan University. Her endless kindness and patience in teaching me how to make posters, network at conferences and edit manuscripts are skills I will use for the rest of my time as a professional scientist. She never preached, but fully understood the value in learning and always took advantage when a teaching moment presented itself. Ulrich Reinhardt showed me the value of professional collaboration as well as provided guidance in constructing a repertoire of coursework that would send me off to graduate school well prepared. And although in Seattle, Mary Moser showed me how to think outside the box, both literally and figuratively and I thank her for opening my mind to a different way of looking at things. My graduate committee has been the most important and influential component of my career at NC State, and I sincerely thank them for everything. Though from a distance, Fred iv Scharf and Ken Pollock provided an incredible amount of knowledge, without which this thesis would not be of the caliber it is. I especially thank my co-advisors, Joe Hightower and Jeff Buckel. Both have been endlessly patient, understanding and supportive throughout the past two and a half years, and I feel very fortunate to have been under their advice. I am very proud to have earned both their professional and personal respect.

Estimates of Red Drum Mortality via Acoustic Telemetry

“…If an aquatic predator consumed a tagged Red Drum and remained in the river, then the Red Drum would be assumed alive initially after predation; however, tag movement would have likely ceased within 1 month given tag expulsion from the predator (Friedl et al. ; Schultz et al. ).…”

“…Finally, five of the seven fish that were confirmed emigrations without harvest elsewhere (Table ) were detected for 28 d or longer on the broad receiver array; this interval is likely too long for a predator to retain an ingested tag (Friedl et al. ; Schultz et al. ).…”

“…A censorship interval of 7 d posttagging was used to account for tagging effects (Friedl et al. ; Ellis et al. ); if an emigration or mortality occurred within this time period, then these Red Drum were censored from all analyses.…”

An accuracy assessment of ultrasonic transmitter locations determined by mobile telemetry in aquatic systems

“…; Friedl et al . ). A telemetry system basically consists of a transmitter that emits radio (27–300 MHz) or ultrasonic signals (27–300 kHz), an antenna or hydrophone that detects the signal (passively or actively) and a receiver that decodes signals into audible sounds (Winter ).…”

Identifying when tagged fishes have been consumed by piscivorous predators: application of multivariate mixture models to movement parameters of telemetered fishes

“…For example, Vogel [8] proposed that tag detections be examined at three scales of resolution to classify an acoustic tag as a live or consumed smolt: 1) examining the acoustic pattern of a tag as it passes a hydrophone, 2) comparing movement direction relative to flow direction (typically, emigrating smolts move with the flow) and 3) comparing the movement rate of a given tag against the movement rates of the entire tagged population. Friedl et al [9] used three criteria for determining natural mortality of telemetered juvenile spot (Leiostomus xanthurus) in estuarine creeks. Tagged fish were considered moribund or consumed if: 1) the tag ceased to move, 2) swim speeds were not within the normal range for the study fish or 3) the fish failed to emigrate from the rearing habitat.…”