Endothermic tunas and sharks: how some aquatic predators turn up the heat up on their prey!

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Wednesday, March 19th, 2014
7:00 PM to 8:00 PM

Tunas and sharks of the family Lamnidae, such as makos and great whites, are some of
the most active and warmest predatory, pelagic fishes hunting in the world�s oceans. Both of these groups of apex predators have independently evolved regional endothermy, the amazing capacity to retain the heat produced by their powerful swimming muscles to maintain elevated body temperatures even in spite of the frigid waters some of these species inhabit. This remarkable example of convergent evolution also extends to a suite of anatomical and physiological specialisations for high-performance-swimming, which is so striking that in terms of their anatomy and physiology tunas and lamnid sharks appear more similar to each other than they do to their close relatives. The ancestors of tunas and lamnid sharks diverged over 400 million years ago, but similar selection pressures have caused both of these groups of thermoconserving fishes to evolve almost identical biomechanical and biochemical designs for swimming. This lecture will review the tuna-lamnid convergence, and describe the similarities in body shape and biomechanics related to high-performance swimming, the mechanisms that allow these animals to be warm, the cardio-respiratory and biochemical specialisations for enhanced oxygen delivery and energy production, and overall, what makes these charismatic and athletic animals so fascinating to physiologists.

Phillip Morrison was born and raised in Nanaimo, where he completed his undergraduate
education at VIU, receiving both a Diploma in Forest Resource Technology (2007), and a BSc Degree in Biology (2011). During his final year at VIU, Phillip worked with Dr. Erick Groot to complete an undergraduate research project that investigated the effects of surgically implanted tracking devices on the swimming performance and physiology of juvenile coho salmon. After a brief stint doing contract work for DFO scientists, Phillip joined Dr. Colin Brauner�s research group at UBC where his PhD thesis seeks to investigate the evolution and functional significance of temperature independent haemoglobin-oxygen binding in regionally endothermic sharks