Killer whales and sea otters
Download
1 / 7

Killer whales and sea otters - PowerPoint PPT Presentation


  • 369 Views
  • Updated On :

Killer whales and sea otters. Daily caloric requirements:. Male killer whale: 308,000 Kcal/day or 5-7 sea otters. Killer whale and seal otter energetics. Female killer whale: 187,000 Kcal/day or 3-5 sea otters. Account for 40,000 sea otters lost over 6 years?.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Killer whales and sea otters' - victoria


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Killer whales and sea otters l.jpg
Killer whales and sea otters

  • Daily caloric requirements:

  • Male killer whale: 308,000 Kcal/day or 5-7 sea otters

  • Killer whale and seal otter energetics

  • Female killer whale: 187,000 Kcal/day or 3-5 sea otters

  • Account for 40,000 sea otters lost over 6 years?

  • 5 sea otters per day per whale x 365 days x 6 years = 10,950 sea otters!

  • 10,950 sea otters eaten x 4 whales would account for 40,000 sea otter losses

Where have all the sea otters gone?


Killer whales and sea otters2 l.jpg
Killer whales and sea otters

  • Sea otters usually not main component of killer whale diet -- why the change?

  • Some fish populations have declined in recent decades

  • Shortage of certain fish caused substantial declines in harbor seals and sea lions

  • Shortage of seals and sea lions resulted in killer whales preying on smaller sea otters

Where have all the sea otters gone?


Killer whales and sea otters3 l.jpg

Killer whales and sea otters

  • Why should we care about sea otter declines?

Where have all the sea otters gone?


Indirect effects on communities l.jpg
Indirect effects on communities otters results in many indirect effects

  • Predation (or parasitism) can reduce competition, preventing competitive exclusion

  • Predators typically feed on several types of prey

  • Prey selected based on its relative abundance

  • Superior competitors can reach high relative abundance, but predation can control such populations

  • Example: removal of starfish (Pisaster) in rocky intertidal results in competitive exclusion by mussels

Where have all the sea otters gone?


Indirect effects on communities5 l.jpg
Indirect effects on communities otters results in many indirect effects

  • Predation (or parasitism) can result in many indirect effects on other species

  • Example: ant-rodent interactions

  • Both ants and rodents eat seeds in Chihuahuan Desert

  • Removal of rodents caused initial increase in ant populations, but then a decrease

Where have all the sea otters gone?


Indirect effects on communities6 l.jpg
Indirect effects on communities otters results in many indirect effects

  • Keystonespecies = species that have strong effect on the composition of the community

  • Removal of keystone species causes a decrease in species richness

  • Example: sea otters eat sea urchins which are superior competitors; if sea urchin populations increase, kelp reduced and species richness drops

Where have all the sea otters gone?


Indirect effects on communities7 l.jpg
Indirect effects on communities otters results in many indirect effects

  • Kelp ‘forest’

Where have all the sea otters gone?


ad