Effects of Simulated Angler Capture and Live-Release Tournaments on Walleye Survival

We examined the effects of acclimation water temperature, live-well (LW) water temperature, and LW dissolved oxygen (DO) concentration on survival of adult Walleyes Sander vitreus subjected to simulated tournament conditions (angling, LW confinement, and weigh-in procedures) under controlled laboratory conditions. We tested three acclimation temperatures (12, 18, and 24◦C), and three LWtemperature differentials (Delta T=−4, 0, and +4◦C) were tested at each acclimation temperature. Survival was monitored after 8 h of LW confinement and during a 5-d retention period in 1,700-L tanks. None of the Walleyes that were acclimated to 24◦C and subjected to simulated tournament procedures survived the 5-d retention period; for fish subjected only to simulated angling at 24◦C, survival during the 5-d retention period was 29%. Five-day survival was generally over 70% at acclimation temperatures of 12◦C and 18◦C, and we observed a significant interaction between acclimation temperature and Delta T; survival was greatest in LWs at −4◦C Delta T for fish acclimated to 18◦C and in LWs at +4◦C Delta T for fish acclimated to 12◦C. Best survival of Walleyes subjected to the stress of angling and tournament procedures was obtained at temperatures 6–8◦Cbelow the optimum temperature for adult Walleyes (i.e., optimum = 20–22◦C). Five-day survival exceeded 70% when LW DO was 5 or 12–15 mg/L (at an acclimation and LW temperature of 18◦C), but survival was 0% when DO was 2 mg/L. Anglers may increase survival of Walleyes through careful manipulation of LW temperature and DO when ambient temperature is at or below 18◦C, but high mortality of angled and LW-retained Walleyes should be expected when ambient water temperatures are 24◦C or greater

Radiographic Assessment of Equine Interphalangeal Joints Asymmetry: Articular Impact of Phalangeal Rotations (Part I)

This study is part of a work to develop a radiographic method that defines objectively the individual conformation of an equine digit and its appropriate trimming. The authors used isolated distal limbs on a rotation support to study the influence of induced foot rotations on several angles measured from specific radiographs. The results of this work enabled the authors to quantify the rotation of the proximal phalanx compared to the distal, and to determine exactly the possible rotation in the distal interphalangeal joint. It was also observed that, faced with a forced rotation of the foot, the digit responded by a hoof plastic deformity, a distal interphalangeal intra-articular rotation and asymmetrical interphalangeal compressions