Exam 3 Flashcards
What is the most primitive mode of spawning
- Eggs release randomly with no parental care
- Ex. red-tailed shark
Iteroparous
-spawn more than once in life
Semelparous
-spawn once and then die
Promiscuous mating systen
- no mate choice (most primitive
- male and female have multiple partners
Polygamy
- one sex with multiple partners
- Polyandry
- Polygyny
Polyandry
-1 female with many males (rare)
Polygyny
- 1 male with several females (common)
- May form Harmes (male takes care of several females)
- May for leks where males aggregate
Monogamous mating system
- pairs stay together throughout a breeding season and sometimes life
- ex. ictalurid catfishes, reef fishes
Marine fish eggs
- buoyant, light
- may be why marine fishes are more widely spread than FW
- pelagic
FW fish eggs
-adhesive eggs, heavier and bigger than pelagic
The classic semelparous spawner
- Salmon
- Build nest and guard the territory until spawning is done, then die
What gender role are most fishes
- Gonochrostic
- sex fixed early and unchanged
Simultaneous hermaphrodites
- male and female gonads in the abdomen of 1 individual
- Hamlets
Sequential hermaphrodites
- Protandrous: male changes to female
- Protogynous: Female changes to male (most common)
Fish with sex changes are mostly found where
the tropics
Parthenogenetic
-all female but use male sperm
In what ways are sharks more advanced in their reproductive style compared to a typical fish?
-some sharks have placental-like ovary to provide nourishment to the embryos
oophagy
-female keeps feeding the embryo with eggs to provide it nutrition
Fish with asymmetrical reproduction
- limits reproduction
- sex parts on left or right side of fish
- four-eyed fish
Functions of courtship in fishes
- Species recognition
- Pair bonding
- Orientation to spawning site
- Overcome territorial aggression of male
-Features involved in courtship
- Color changes
- Sound production
- Visual displays
- Chemical signals
Forms of parental care
- Burying eggs
- Chasing predators
- Keeping young in nest or school
- Internal gestation
Costs of parental care
- Guarding means less chance to feed, may reduce gamete production
- predation risk to parent when guarding
- Number of eggs is inversely related to amount of care
Diel patterns
- diurnal: 50-66% of species
- nocturnal: 25-33%
- crepuscular: 10%
Why is diurnal more distinct in tropics
- because there is less twilight times in tropics
- due to the minimal crepuscular habitat
Why is sleep common among fishes
- Energy is conserved
- Avoid predators when light suboptimal for eyes
What is the quiet period in fish in the tropics
-during crepuscular time, diurnal fish are going to sleep and nocturnal fish are just waking up
What distinguishes fish from most other vertebrates
- intermediate growth (also birds)
- larval stages (free living most of the time)
Developmental stages in fish
- larva fishes put their energy into length (helps them swim faster)
- Metamorphosing stage puts energy into fat (helps to survive winter)
As the size of eggs _____ parental care _____
increases increases
Some components of reproductive effort
- Energy to gonad
- Body mass
- Courtship and spawning
- migration
Causes of meristic and morphometric variation
- Environmental variation (temp)
- involves longitudinal meristic counts and allometric growth of body morphology
Critical Period Hypotheisis
- in 1-2 days after hatching, fish must find food
- after this point, the fish will die even if it does find food
- has a big effect on population dynamics
Point of no return
-cant feed even if they find food
Match-mismatch hypothesis
-timing of larval development needs to match peak abundance of key prey organisms for each life stage
Terminology of fish STEPS
- Yolk sac
- Pre flex
- Flex
- Post flex
- Juvenille
Yolk sac
-yolk provides fish with food and forms digestive tract
Pre flex
- stage when vertebrae developing grow straight out
- fins develop inside the fin fold
- critical period, no more yolk and fish needs to find food
Flex
-stop making new vertebrae and form a new swimming tail
Post flex
- most basic fins are formed, fin rays present
- nice mouth/gills/digestive tract
- fins are not fully developed
Juvenille
-fins are fully developed
Indirect ontogeny
-2 stage life with metamorphosing, fish from juvenille looks nothing like larvae
Direct ontogeny
-no metamorphosing, larvae looks like juvenille (flying fish)
Theory of saltatory ontogeny
- fish develops numerous things in one stage, they once they are developed, it jumps to a new stage and so on
- May help explain evolution
three foundations of fishery science
- age structure of fish populations
- Energetic dynamic
- Life-history variations
Why are otoliths used to age fish
- they are not reabsorbed back into body like scales
- made out of calcium carbonate
How do most fish feed
-through suction feeding
Function of gill rakers
- filter out food like zooplankton
- if a fish has a lot of gill rakers then its likely eating plankton
- few gill rakers means more fish in diet
Function of pyloric caeca
- absorbs fat which increases surface area
- as # of pc increases, % fish in diet increases
Gut length in fish
- the larger the gut, the more vegetation in diet
- Piscivore and invertebrate feeders then gut will be less than 1 x body length
- omnivore - 1-2 x body length
- Herbivore/deterivore - 5-28
Truncated cone model for suction feeding
-when the fish opens its moth and expands buccal chamber, vacuum is created that quickly sucks in food items in front of mouth
Why are there so many different bones and muscles in the gill arches and jaws
-provides abundant opportunities for evolution of diverse feeding
Steps in suction feeding
1) Preparation, inward squeeze, increases pressure
2) Expansion: suction, short
3) Compression increases pressure, pushes water out gill openings
4) Recovery: return to pre-preparatory position
Two types of colors in fishes
- Pigments
- Structural colors
Pigments
- primarily in chromatophores
- Carotenoids
- Melanophores
- Leucophores and iridophores
Carotenoids
- reflect yellow, red, orange
- from fishes diet only, cannot manufacture
Melanophores
- Black melanin crystals
- can be manufactered
Leucophores and iridophores
-white/silver reflections from guanine crystals
Structural colors
- light reflected from structures rather tahn pigments
- green, blue, violet, from light refracted by layers of skins/sclaes
Static color pattern
- informs about species, sex, reproductive condition or age
- longer-term seasonal or ontogenetic changes
- most likely controlled by horomones
Dynamic color patter
- involves rapid exposure of a previously hidden structure
- often involve movement of body/fins, operculate, and/or mouth
- short-term changes primarily under influence of nervous system
What is the issue with color shading
-depends on where the light is coming from
Disruptive coloration in fishes
- eye ornamentation or dazzle shading
- have a wild color pattern so fish doesn’t look like a fish
Shoaling
-unorganzied grouping
Schooling
- organized, often polarized
- two types: polarized and unpolarized
Polarized schooling
- all individuals oriented in the same direction
- uniform speed and direction
Non-polarized schooling
-Brought together by mutual attraction, but not organized like a polarized school
Behavioral responses to a predator in schools
- Group jump
- avoid
- compact
- fountain
Schooling in fish adaptive advantages
1) hydrodynamic efficieny
2) Reduce predation risk
3) Increased feeding efficiency
4) Increased reproductive success
