• ucsantabarbara twitter avatar
    A new construction project on campus aims to ‘pave’ the way for updated utilities & better infrastructure at #UCSB. https://t.co/FkRmgpo8LC
    4 hours 1 min ago
  • UCSBgauchos twitter avatar
    WWP: Gauchos End The Day With A Dominate Win And A Close Loss https://t.co/U0mHxrjEPb
    1 day 1 hour ago
  • UCSBgauchos twitter avatar
    WBB: Gauchos Share The Cape In All-Around 74-62 Win Over Hawai'i On Super Hero Night https://t.co/7JozUy4Wi1
    1 day 3 hours ago
  • UCSBgauchos twitter avatar
    Vincent Hits 1,000 Point Mark But UCSB Loses at UC Riverside, 65-55 https://t.co/rvtR2CFZwU
    1 day 3 hours ago
  • ArtsandLectures twitter avatar
    Tune in to @prairie_home to hear @odonovanaoife & pals performing songs from #lalaland! Now on KCLU
    1 day 4 hours ago
  • UCSBgauchos twitter avatar
    WBB: FINAL UCSB 74 - Hawaii 62 Gauchos rack up season-best 4th straight win, improve to 9-9 (4-1). Edelman 19pts 6reb, Toler 17pts off bench
    1 day 4 hours ago
  • UCSBgauchos twitter avatar
    WBB: We're inside the last minute of regulation, Toler with 10 points in the final quarter. 71-60 UCSB 46.1 remaining.
    1 day 5 hours ago
  • UCSBgauchos twitter avatar
    WBB: Gauchos roar off the first 8pts and Hawaii needs to talk about it! 58-45 UCSB 7:54 remaining in the fourth quarter.
    1 day 5 hours ago
  • UCSBgauchos twitter avatar
    WBB: End of Third Quarter UCSB 50 - Hawaii 45 Hernandez goes for 8pts in 3Q. Gaucho pep band is ready for the fourt… https://t.co/VDP5Er1MZ1
    1 day 5 hours ago
  • UCSBgauchos twitter avatar
    WBB: Gauchos respond to a mini Hawaii run with a Durr and-one, and back-to-back 3's from Hernandez. 45-37 UCSB 4:56 left in 3Q.
    1 day 5 hours ago
  • UCSBgauchos twitter avatar
    WBB: Halftime UCSB 31 - Hawaii 26 Edelman with team highs 10pts and 3rebs. Gauchos a 14-8 pts in paint advantage, 11-2 off turnovers.
    1 day 6 hours ago
  • UCSBgauchos twitter avatar
    WBB: Toler with an emphatic chase down block from behind! She has first 2 buckets for UCSB in 2Q. 27-19 Gauchos, 4:21 before halftime.
    1 day 6 hours ago
  • UCSBgauchos twitter avatar
    WBB: End of First Quarter UCSB 23 - Hawaii 15. Porter leads all scorers with 9pts, 3/4 from downtown. Gauchos 11pts from 5 Hawaii turnovers.
    1 day 6 hours ago
  • UCSBgauchos twitter avatar
    WBB: Gauchos sink their first 4 from the field, 3/3 from downtown and lead 18-9 at 1Q media break. Porter 2/2 for trey, Edelman doing work.
    1 day 6 hours ago
  • brenucsb twitter avatar
    Growing an interest in nature: #UCSB students & Edible Campus Project plant seeds of sustainability in preschoolers https://t.co/dyoiFtroWo
    1 day 12 hours ago

Not-So-Cold-Blooded Creatures

A new study finds that a rise in body temperature enables certain species of fish to maximize their swimming distance and speed
Wednesday, May 6, 2015 - 09:30
Santa Barbara, CA

Salmon_shark_ENH.jpg

Salmon shark

The salmon shark is one of four shark species that can raise their internal temperatures higher than that of the surrounding water.

Photo Credit: 

Yutaka Sasaki

Jenn Caselle 3.jpg

Jenn Caselle

Jenn Caselle

Photo Credit: 

SONIA FERNANDEZ

Marine scientists have long known that some species of fish possess a unique physiological characteristic — a web of arteries and veins lying very close together — that enables them to raise their internal temperatures higher than that of the water surrounding them.

Now, a new study by an international team of scientists that includes UC Santa Barbara research biologist Jenn Caselle has demonstrated that species possessing the ability to warm their core — a process called endothermy — are able to swim two and a half times faster than those whose body temperature doesn’t change. In addition, these species, which include some sharks and tunas, can also swim twice as far — ranges comparable to those of warm-blooded animals such as penguins and other marine mammals. The researchers’ findings appear in the Proceedings of the National Academy of Sciences.

“The cost of moving faster and farther is high so there has to be an ecological reason that outweighs the physiological expenditure,” Caselle said. “These endothermic fishes are putting a lot more energy into each unit of movement than their cold-blooded counterparts are.

“In fact, the estimated cost of transport is twice as high, but in return they’re getting benefits from that increased swimming speed and wider range of migration,” she added. “We hypothesize these gains allow these endotherms to be more efficient hunters and to span larger areas in their migration, which probably provides feeding and reproduction benefits.”

To conduct the study, the team combined existing data with new information they obtained by attaching sensors — designed and built by lead author Yuuki Watanabe of Japan’s National Institute of Polar Research — to several sharks in different locations around the world. The researchers’ analysis suggests that warmer “red” muscle endothermy permits speedier cruising and greater endurance, which in turn enables these fishes to swim long distances relatively quickly. This characteristic, the marine scientists speculate, allows the fishes to take advantage of seasonally variable food sources.

Of those examined in the study, four shark species are endothermic — salmon, porbeagle, white and shortfin mako — as are five species of tuna — yellow fin, southern bluefin, Atlantic bluefin, Pacific bluefin and albacore. One species in particular, the white shark, has a migration range greater than that of the humpback whale.

 Of specific interest, Caselle noted, is the fact that endothermy evolved independently in these distinctly different groups of fishes. The two taxonomic groups diverged more than 450 million years ago, and their common ancestor was most likely cold-blooded. “The mechanisms of convergent evolution aren’t always the same, although in this case they pretty much are,” Caselle said. “There are only a limited number of ways a fish can rewire.

“This research begins to shed light on possible reasons why these endothermic fish evolved in this way,” Caselle concluded. “Our paper contains almost every piece of electronically recorded information in the literature right now — and that’s not a lot. We’d like to be able to expand the use of sensor-captured data to other groups of fishes in order to build a dataset we could analyze to see what different species are doing in terms of their movements and speed.”

Contact Info: 

Julie Cohen
julie.cohen@ucsb.edu
(805) 893-7220

Topics: