Fish Lecture Final Exam Flashcards
(96 cards)
How can a fish deal with gravity (sustain buoyancy in water)? (6 ways)
- ACTIVE: Swimming forward through the water using fin modifications, provides lift (Pelvic fins, Caudal fins)
- SEMI-ACTIVE: Filling body up with air, gas or swim bladder
- STATIC: Reducing density of certain structures to make them lighter (having thin bones)
- Cartilage can be used in replacement to bone up which is lighter than bone.
- Use UREA and OILS to make solid parts of the body neutrally buoyant
- Some fish do not sustain buoyance, they live on benthic surface
Specific gravity of:
a) freshwater
b) saltwater
c) overall bony fish
a) Freshwater: 1.000
b) Saltwater: 1.026
c) Overall bony fish: 1.06 - 1.09
Descibe PHYSOSTOMES
- Species that have gas bladder connected to a tube to gut (more primitive fish) allows for gas bladder to be filled or emptied
Describe PHYSOCLIST
- Species with closed gas bladder
What is unique about the fishes eye lens?
- The lens is SPHERICAL in shape, this would normally result in a fuzzy image
- The composition of the fish’s eye lens changes from the center to the outer edge resulting in changing refractive index
What percentage of the worlds fish are:
a) Freshwater
b) Marine
c) Diadromous
a) 41.2%
b) 58.2%
c) 0.6%
Diadromous
Moving from freshwater to marine environments and vice vera
Anadromous
Spawning in freshwater and rearing in marine environments (ex. salmon)
Catadromous
Spawning in marine environments and rearing in freshwater (ex. eels)
What percentage the earths water is freshwater?
1%
Describe PELAGIC
Open oceans
Define EPIPELAGIC
Area of the ocean where enough sunlight can enter for photosynthetic processes (generally up to 200m in depth)
Describe BENTHIC
Sea floor
Littoral
Shallow regions near shoreline of ocean or freshwater lakes
What is the difference between TROLLING and LONGLINING?
- TROLLING: A fishing method where line and hooks are dragged behind a vessel
- LONGLINING: Large number of short lines carrying hooks are attached to a longer main line at regular intervals. The short lines are suspended horizontally at a predetermined depth with the help of surface floats
How many lines are allowed when trolling?
6 lines
Describe the following trolling gear:
- Gurdy
- Block
- Davit
- Pig
- Cannon ball
- Gurdy: WINCH that reels line in and out
- Block: PULLY in which line runs through from the gurdy
- Davit: ARM which hangs over the edge of the boat, raises, or lowers gear
- Pig/float: rectangular Styrofoam FLOAT that keeps the lines apart
- Cannon ball: Lead WEIGHT attached to the end of the line
Describe the following trolling gear:
- Flasher
- Hoochie
- Lures
- Leader
- Snap
- Flasher: Metal or plastic ATTRACTOR
- Hoochie: Plastic LURES
- Lures: spoons and plugs
- Leader: LINES from main line to hook
- Snap: CONNECTS the leader and hook to the main line
What are the three types of trawling and briefly describe?
1) Mid-water otter trawl: Net is towed in mid-water
2) Rock-hopper/bottom trawl: Net is dragged along sea bed
3) Beam trawl: Mouth of the trawl has metal beam which is dragged along the sea bed, used a lot for shellfish.
Name the 7 parts of a trawl net
1) Wings
2) Belly
3) Cod end
4) Trawl wrap
5) Otter doors
6) Headrope float
7) Iron bobbins
Why is bottom trawling so bad?
Highly damaging to the sea bed
Describe longlining
Large number of short lines carrying hooks are attached to a longer main line at regular intervals. The short lines are suspended horizontally at a predetermined depth with the help of surface floats
What are the following pieces of equipment used for longlining?
- Skate
- Gangion
- Radar reflector
- Gaff
- Skate: main long line with baited hooks set on the ocean floor
- Gangion: short line with baited hooks attached to main skate
- *See diagram pg. 39**
- Radar reflector: metal device on top of buoy to indicate where the line is or to indicate where your boat is to other vessels
- Gaff: hook on a pole used for lifting fish
What are the 3 types of hooks?
J shaped hook
Circle shaped hook
Barbless hook