BIO 358 1st Edition Lecture 18 Outline of Last Lecture I Notes from Osteology Lab Outline of Current Lecture I Methods of Tracking dives II D Tag III Right Whale D Tag Study IV Beaked Whale D Tag Study Current Lecture Diving Part 2 Acoustic Telemeter puts out a sound to tell where an animal is Radio Telemetry UHF ultra high frequency Satellites All of these tell us how deep they are Dr Peter Tyack and Mark Johnson electrical engineer what happens when animals dive D Tag Mini computer With hydrophone Pressure Depth 10 GB of memory can stay on animal a long time HFreqency sensors Suction cup attachment Floats and has a radio antenna so you can find it How to get the tag on an animal place it on the animal with a really long pole Tag records behavior continuously without bias throughout a dive cycle These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Swimming behavior Vocalizations Sound in environment Time depth and pressure D tag has revolutionized what we know about diving behavior North Atlantic Right Whale and Beaked whales Eubalena Glacialis Single most common reason right whales died was ship strikes and entanglement D tag used to study swimming behavior and figure out if they could respond to acoustic stimuli to help avoid vessel strikes 3 questions How to right whales swim during diving o Positively buoyant o Why is this important o Buoyancy changes can save an animal energy while it is diving Williams study o No one ever looked at diving behavior o They put cameras on the animals facing head or tail also included TDR o ALL species animal worked to get away from the surface started dive by stroking continuously and at about 80 meters depth they would stop stroking but they would keep moving but stop stroking o Hypothesis air in the lungs compressing at depth animal is denser and becomes negatively buoyant they can keep descending but they no longer need to power it using strokes save energy o Once at depth they have to stroke to become positively buoyant again to get to the surface o Same pattern as in a right whale Why not Right whale to kill they float they are positively buoyant animals big blubber layer do they ever become negatively buoyant D tag right whale study 8 tags whales had to propel themselves downward the entire way down at steep angles they ascent passively to the surface they do the exact opposite of all the other species studied so far we would not have known that without D tags Passive ascent problems o A right whale at the surface that dives to avoid a vessel likely has its vertical descent slowed by its positive buoyancy o Passively ascending whale may not be paying as much attention or have the same maneuverability to avoid a ship at the surface o Positive buoyancy may enhance vulnerability to ship strikes Do right whales respond adaptively to ship noise run away Can a human design acoustic alert signal to help them avoid ships o No not respond adaptively and run away o Taged 10 whales and followed o Played sounds to whales ship sounds acoustic alarm signal whale social sounds and silence o Monitored whale swimming and diving behavior o Alarm signal designed by bioacoustitions o Whales exhibited no measurable response to ship sounds whales social sounds and silence o Alert signal response Extreme response Abandoned foraging at depth Executed a shallow angled high powered ascent Remained at or near the surface for entire exposure time to signal Spent significantly more time at a sub surface depth of 1 10 m not good for ship avoidance They make themselves invisible at the surface ALARM ENHANCES RISK Non adaptive response D tag important conservation tool if we used the alarm without the D tag experiment we wouldn t have known the risk of it 2008 ship strike reduction rule slowed down boats in some areas in 2014 it was extended and a sunset clause was deleted Beaked Whale Strandings and Sonar Since 1985 there has been a series of atypical multispecies beaked whale mass stranding events internationally Events occurred in temporal and spatial association with military use of tactical mid frequencies sonar 3 6 kHz Veterinary assessment concluded that clinicopathological findings most similar to decompression sickness in human divers in vivo gas bubble formation associated with navy sonar o Indirect Effect behavior change causes bubble formation o Sonar is causing there s animals to change stereotypic dive behavior which causes bubble formation in supersaturated tissue o What is the normal diving behavior of beaked whales Deep diving pelagic animals before 2006 with knew about these animals through strandings 2006 tyack and colleagues but a D tag on diving animals 7 tagged whales from Ligurian Sea 700 2000 m deep 3 whales tagged in Canairy isalnds Mesoplodon densirostris Ziphius cavirostris dive profile deepest dive ever documented for a marine mammal 1888 meters over 6 200 feet dive record goes up down up down then a deep dive yellow squiggles on dive record time animal is echolocating don t start until 500 meters once they are down there they are echolocating a lot foraging absolutely silent in first 400 500 meters shallow divs out of date march 2014 deep dive up series of shallow dives down up series of shallow dives Schor et al implantable tag 37 hundred hours of diving recorded new record 2992 meters almost 1 9 miles round trip 4 miles all on a breath hold 2 hours and 17 minutes Beaked whale diving Record dive 85 min 30 prey captures per dive ascent rate is approximately 2x longer deep foraging dives always followed by series of vocally silent shallow dives diving pattern very stereotypical WHY display this diving pattern hypothesis recompression diving pattern people dispute continual collapse and expansion of lungs doesn t get nitrogen into solution it aids in the additional loading of oxygen continuing to load at a high rate may enhance risk of decompression sickness hypothesis permits whales to recover from oxygen debt Tyack et al 2006 hypothesized that beaked whales exceed their aerobic dive limit ADL by almost two times Beaked whale strandings and sonar Could changing diving pattern in response to sonar cause in vivo bubble formation and decompression sickness To date we do not know but D tag studies have showed that beaked whales have very stereotypical dives How would you test if sonar is causing these animals to change diving behavior o Ramped