Bioenergetics of Juvenile Scalloped Hammerhead Sharks
Kaneohe Bay, Oahu Hawaii is well known nursery ground for the scalloped hammerhead shark. Adults come into the bay to give to their young in the spring and early summer. Pups use the bay as a protective nursery until they are large enough to enter the pelagic environment. It has been estimated that up to 10,000 pups can be born in this bay over the summer.
Little is known about the impact that this shark population has on Kaneohe Bay. One way to measure this impact is by quantifying the energetic demands of this predator.
This is the large swim tunnel respirometer that was custom-built for this project and maintained at the Hawaii Institute of Marine Biology. This aquatic "treadmill for fish" was used to measure the metabolic rate of young scalloped hammerhead sharks and related swimming behavior (tailbeat frequency, swimming speed).
Hammerhead sharks are known as obligate ram ventilators and must continuously swim in order to breathe. We developed a custom acoustic transmitter that functions like a "pedometer". This device produces an acoustic pulse every time the shark tail wags.
Because tailbeat frequency, swimming speed and oxygen consumption over a range of seasonal water temperatures were strongly correlated, I was able to use tailbeat frequency as a predictor of swimming speed and metabolic rate. Information on energy consumption on sharks in the laboratory was used to determine the energetic requirements of free swimming sharks in the bay.
Metabolic Rates of Juvenile Whitetip Reef Sharks
Using the large swim tunnel respirometer, we have measured metabolic rates of other shark species, such as whitetip reef sharks. These sharks are much easier to work with because they are non-obligate swimmers and can rest on the bottom for prolonged periods of time. This was part of the Hawaii Institute of Marine Biology summer Pauley Program.
Metabolic Rates of Southern California Fishes
We've built and used a variety of annular respirometers to measure resting and routine metabolic rates of a variety of nearshore gamefishes and rays.
Kim Johnson measured the mass specific routine metabolic rate of kelp bass across a range of sizes.
Hayley Zemel used our 30 liter respirometer to measure metabolic Q10 of round stingrays, and Derek Castleman used this system to measure the metabolic Q10 of California sheephead.
Our new swim tunnel respirometer (Loligo systems 90 liter chamber) with fiberoptic O2 probe and temperature-control system is now being used for swimming kinematics and metabolic rate studies. Emily Meese and Kristin Privitera-Johnson has recently used it to measure resting metabolic rates of California halibut, and Sarah Luongo has been using it to measure metabolic Q10 of California horn sharks.
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