Chapter 24: Fishes, Class: Petromyzontida aka Lampreys

Question 1

Do they have a jaw or lack one?”

Answer 1

• lack

Question 2

What is Petromyzon marinus?

Answer 2

• species of lamprey that lives in a marine environment occurring in both Atlantic coastlines

Question 3

Half of the 20 species of lampreys in NA belong to what?

Answer 3

• nonparasitic brook dwelling species

Question 4

Reproduction and Development:

• They ascend to _____ to breed.
• Marine forms are anadromous meaning what?
• In NA all spawn in the ___ or ___.
• Who builds the nest/how?
• mating?
• Fertilization?

Answer 4

• freshwater streams
• leave the sea as adults to spawn upstream
• winter or spring
• Males build the nest by lifting stones with oral discs and using body vibrations
• Females anchor themselves to a rock and the male attaches to her head
• As eggs are shed into the nest, males fertilize them.
  L> adults die soon after mating

Question 5

Parasitic Lampreys: 
- Live in what habitat(s)? 
- Describe the process of feeding!
- life expectancy?
-Anadromous life expectancy?
L> what about nonparasitic lampreys and feeding? Their life cycle?

Answer 5

• marine parasitic lampreys migrate to the sea but others remain in freshwater
• Attach to a fish via sucker like mouth, sharp teeth rasp through flesh as they suck fluids. They inject an anticoagulant into a wound. Once engorged the lamprey drops off but the wound can be fatal to the fish.
• Parasitic freshwater adults live 1-2 years before spawning and dying
• Anadromous forms live 2-3 years
• nonparasitic lampreys do not feed, their digestive tract degenerates as an adult, they spawn and die.

Question 6

What was the impact of lampreys moving into the Great lakes after the Welland Ship canal was deepened?
- solution?

Answer 6

• they destroyed lake trout which is commercial species along with overfishing.
• they then went after rainbow trout, whitefish, lake herring, chubs and other species.
• the lamprey populations declined both from depletion of food and control measures such as Chemical larvicides in spawning streams and the release of sterile males