Fish Ecology Flashcards
Pelagic
Open Water species (eg. Tuna, Salmon, mackerel, anchovy)
Demersal
Close to Bottom or Bottom-dwelling” (eg. rockfish, halibut, cod, flounder, haddock)
Diadromous
moving between freshwater and marine
Molluscs
eg.clams, snails, etc.
Crustaceans
eg. shrimp, crabs, lobsters
What are the 4 trophic levels?
- Phytoplankton
- Zooplankton
- Prey Fish
- Top Predators
Definition of a fish
- Aquatic
- Poikilotherm - ectothermic/cannot regulate their own body temperature, with the exception of tunas and mackerel sharks which are warm-blooded.
- Vertebrate
- Gills (throughout whole life)
- Often having Scales and limbs (in shape of fins)
Rete mirabile
- Complex of veins close together
- Heat exchanger in warm blooded or fast moving fish
- allows greater blood temp than ambient temp
Fish measurement - most common
- (postorbital-hypural length). - from the posterior of the orbit to the hypural plate
- Used for adult salmonids on spawning grounds
- hooked nose and tail abrasion can make measuring difficult, so this gets around
Other fish measurements
- Girth - measured around the largest diameter. Girth measurements can be an indicator of ecosystem health.
- Head length
- Snout length
- Eye diameter
- Jaw length
- Anal fin base length
Meristic measurements of fish
- Vertebrae
- Fin rays
- Lateral line scales
- Scales on sides
- Teeth
- Gill rakers
- Pyloric caeca
Pharyngeal teeth
teeth in the back of the throat
Branchiostegal rays
curved bones that support the branchiostegal membrane
Taxonomy
Academic discipline of defining groups of biological organisms. On the basis of shared characteristics, and giving names to those groups.
Nomenclature
The scientific naming of species whereby each species receives a latin or latinized name of two parts; first indicates the genus and second species.
Phylogeny
the “tree of life”, hierarchical structure in which every lifeform is related to each other.
Genetics
branch of biology that deals with heredity, mechanisms of hereditary transmission and the variation of inherited characteristics among similar or related organisms.
Anatomy
a. The body structure of a plant or animal or of any of its parts
b. The science of the shape and structure of an organisms and their parts
Zoogeography
is the science that attempts to describe
and explain the distribution of animals in space and time.
Orientation of fish, looking left clockwise
left anterior
top dorsal
right posterior or caudal
bottom ventral
Fork Length
- From tip of nose to fork in tail
- Used for salmonid juveniles and other fish with clear fork in tail
Total length
- tip of nose to end of tail
- flounders, sculpins, others w/rounded tails
Counting dorsal and anal fin rays
- Don’t count ones on the right that are short
- go biggest to smallest rays
- for the ones that fuse near the base - call these 1
Counting scales
- count above and below lateral line
- dont count the lateral line scale, or at the top or bottom of fish
- start at the origin of the dorsal fin, then count along the natural line
