1. Lecture 17. October 15, 2008 Osmoregulation & Excretion How many students are missing the lab notebook? Need 2 graduate student volunteers to enter data.

2. http://www.npr.org/templates/story/story.php?storyId=95567915&live=1&ps=bb1 Deepest Sea Fish Ever Found!! - Liparidae - Snail Fish Family - Scorpaneiformes - 4.8 miles down - no airspaces - despite no light, it has eyes - presumably to see bioluminescence - if you subject nerves or muscle to that much pressure, they stop working. - must have adaptations that allow for all that pressure

3. Thought Question Active fish have higher relative surface areas than inactive fish. Why don’t all fish have high relative surface areas?

4. Dissolved Solutes in Different Types of Water

5. hagfish Source[Na+][K+][Cl-]othersureamOsm seawater4399513881050 hagfish4868508201035

6. sharks - hammerhead Source[Na+][K+][Cl-]othersureaTMAOmOsm seawater439951388001050 shark2556241103441721118 Sharks use trimethylamine oxide (TMAO) which protects them from high urea.

7. toadfish - SW Source[Na+][K+][Cl-]othersureamOsm seawater4399513881050 toadfish18051969452

8. goldfish - FW Source[Na+][K+][Cl-]othersureamOsm freshwater0.250.040.231<5 goldfish13031253274

9. Source[Na+][K+][Cl-]othersTMAOureamOsm freshwater0.250.040.231<5 FW stingray150- 7--308 freshwater stingray

12. http://www.biology.ualberta.ca/courses/zool241/index.php?Page=1815 Gill Models Take home point: This is somewhat complex.

13. Some saltwater teleosts lack a glomerulus in their kidney. What does a glomerulus do? Why would this be a good thing for saltwater teleosts?

15. Thought Questions 1. What properties/traits that affect osmoregulation do you think would change when catadromous eels migrate from f.w. to s.w. to spawn? 2. What properties/traits do you think would change when anadromous lampreys migrate from s.w. to f.w. to spawn? 3. Why are saltwater Elasmobranchs have a slightly higher total ion concentration than the surrounding seawater?

16. Review Questions. 1. Distinguish between an osmoregulator, an osmoconformer, an ion regulator, and an ion conformer. For each of the following taxa, explain their strategy in regards to ion/water balance: hagfish, shark, toadfish, goldfish, f.w. stingray. 2. Why do inactive fish have low relative gill surface volumes? Why not have a large gill surface volume to get more O2 in the body? Hint: what problem does large gill surface area lead to? 3. How do fish regulate their pH? Did you read page 91? 4. Why don’t freshwater stingrays maintain urea in their bodies? Why do saltwater Elasmobranchs maintain TMAO in their bodies? 5. What properties/traits that affect osmoregulation do you think would change when catadromous eels migrate from f.w. to s.w. to spawn? What properties/traits do you think would change when anadromous lampreys migrate from s.w. to f.w. to spawn? 6. From the book. What hormones are involved in the transition from freshwater to saltwater? What hormones are involved in the transition from saltwater to f.w.? 7. Why do some saltwater teleosts lack a glomerulus?