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CONFERENCE SCHEDULE UPDATES & CHANGES: As a result of the prolonged government shutdown, we experienced a number of cancellations and changes to the schedule. Cancellations and changes are listed here (as of January 26, 2019). 

Tuesday, January 29 • 6:00pm - 9:00pm
(P38) Validating Daily Otolith Increment Deposition in Aquarium-Reared Juvenile Walleye, Sander Vitreus

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AUTHORS. Kaitlin Ulin, L. Zoe Almeida – Ohio State University; Taylor A. Brown, Cornell University; David Dippold, Stuart A. Ludsin, Elizabeth A. Marshall – Ohio State University

ABSTRACT. The daily age and growth rate of a juvenile fish can provide useful information about early life conditions. Researchers frequently take advantage of the fact that fish otoliths accrue daily rings, which can be counted and measured, to estimate ages and growth rates.  Previous studies have indicated, however, that aging juvenile walleye, Sander vitreus, with otolith increments past 42 d is difficult, if not impossible. This difficulty is partially due to the development of accessory primordia (a second growth plane on the otolith), a problem exacerbated by otolith preparation techniques that obscure rings on different planes. Herein, we examined the accuracy of aging walleye before and past 42 d using known-age, aquarium-reared walleye and a modified otolith preparation technique. Our otolith preparation technique involved gently grinding the convex side of the otolith in three planes: the core, the middle, and the edge. By grinding on the convex side, we removed material along a curved axis to allow visibility of rings from the hatch-check to the most recently laid ring and, therefore, allowed us to age the fish from hatch to capture. Walleye were hatched on April 20, 2018 (± 3 d) and reared for 96 d; sagittal otoliths were collected on days 10, 41, 56, 79, and 96 post-hatch. Otoliths were aged by three readers. We are comparing reader estimates of ages to known ages and analyzing among- and within-reader error to determine if error lies within readers’ interpretation of rings, or if accessory primordia inhibit clear interpretation of daily rings past 42 d. Future experiments manipulating temperature will be conducted to confirm if our findings are consistent under different environmental conditions known to affect otolith growth patterns.

Tuesday January 29, 2019 6:00pm - 9:00pm
SUPERIOR BALLROOM C/D

Attendees (7)