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Diversity of Wisconsin Fishes reproduction
habitats
Reproduction strategies
Early life history- terms
Ecology of early life history
Lab – Wisconsin fishes part 2
Non-gaurding , Pelagic
Alewife - inshore waters, eggs settle
High fecundity
High early stage
mortality
Gizzard shad - Often move up rivers, eggs drift down
Non-gaurding , Pelagic
Freshwater drum eggs float on surface until hatch
Paddlefish eggs are sticky when fertilized, adhere
to the first thing they touch
Non-gaurding , Benthic – fine substrate
Spottail shiners spawn on gravel and silt substrates
Non-gaurding , Benthic - Crevice
Spotfin shiners use rock crevices to hold eggs
Non-gaurding , Benthic –vegetation
Northern pike
prefer flooded
vegetation in
backwaters
Non-gaurding , Benthic –vegetation
Banded killifish spawn gets entangled in aquatic vegetation
Non-gaurding , Benthic – coarse bottom
Lake trout and lake whitefish spawn over large broken
coble areas
Non-gaurding , Benthic – stream
Pacific salmon and brown trout dig redds – clean gravel
where stream water upwells
Non-gaurding , Benthic – stream
Brook trout exclusively use groundwater upwelling areas in
lakes and streams
Guarding , Nests – nests of plants
Guarding means
higher survival
Sticklebacks make nests of algae and macrophytes and
then lay eggs inside the nests
Gaurding , Benthic – Underside of rocks
Both round gobies and Johnny darters spawn under rocks,
attaching the eggs to the underside of the rocks
Aggressive defense
can incur high costs
to parents or death
Gaurding , Nests – gravel
Common in centrachids
also lamprey, nests are
often fanned to increase
water flow and remove
sediments
American brook
lamprey
Smallmouth bass
Gaurding , Nests – Holes and burrows
Catfish and
bullheads make
burrows or use
existing holes
Noodling Time:
http://www.yout
ube.com/watch?v
=zOjA8Puh1BM
Gaurding , Nest – fine sediment
Crappie nests
associated with
vertical vegetation in
fine sediments
Livebearers , (none native) Mosquitofish
60 -100 progeny per brood, born live, male has modified
anal fin to impregnate female
Why bear live young?
Life history strategies
Multiple strategies: Bluegill – parental care or Cuckolder
Female mimic
http://publish.uwo.ca/~bneff/research_beea.htm
Life history strategies
Multiple strategies: Pacific salmon
‘Jack’ – 2 year old male
Normal 5-6 year old male
Female mimic
Spawning variants
How often: Semelparous = once, Iteroparous = more then once
Fish evolve to spawn in different locations
Temiscamie – strain
Little Tupper strain
Tributary spawner
Shoal spawner
Assinica- strain
Outlet spawner
Why...think about the emerged fry!
Early life history
Same basic pattern
Eggs
Larvae (alevin)
Juvenile
Adult
Snook
Salmon
Diverse Larvae
Majority of mortality occurs in early life
Most fish are r selected – lots of offspring,
little care, few make it
Verhulst equation
Small changes in survival at any stage = big
difference in year class strength
Year class strength
Measure or index at some
point when fish can be
easily caught.
Long term data is critical
since each year is only one
data point
What could influence year
class strength?
At what stages?
Factors that influence early life survival
Temperature
-How quickly adult fish mature and spawn
-How quickly eggs hatch
-Growth rate of larvae and YOY
Food availability
-Is the right food available once yolk sac is used up?
-As they grow does the food out grow them?
Water level
-Eggs can be left high and dry or smothered?
Predation
-Do larvae face a predator gauntlet?
Match/Mismatch Hypothesis
– Conditions match what is needed
Year class strength: egg stage
gravel size influences survival from egg to larvae
Year class strength: YOY – young of year
River flow influences survival of young of year
Year class strength: temperature
Food Abundance Fluctuations
Predation
Lake trout eat alewives…right?
What about larval lake trout?
Must fill swim bladder at surface
(physoclistous )
Great lakes LT spawning reefs
Match/Mismatch
Yellow perch hatch
Eat small copepods, then switch to Daphnia
Yellow perch hatch
Eat small copepods but Daphnia show up too late
Wisconsin Fishes part 2
Esocidae (Pikes)
Grass pickerel
Muskellunge
Northern pike
ID’ing esocids
Northern pike
Pores
Pickerel – 4
Pike – 5
Muskie – 6-9
Branchial. Rays
Pickerel – 12
Pike – 14-16
Muskie – 16-19
Muskellunge
Identify with pores and or branchiostegal rays
Umbridae (Mudminnows)
Central mudminnow
Fin placement
Homocercal tail
Lottidae (Burbot)
Homocercal tail
Long continuous
anal and dorsal
fins
Single chin barbel
Aphredoderidae (Pirate perch)
Big dorsal
Starts here
Ends here
"Migrating anus"
Percopsidae (Trout-perch)
Trout-perch
Big head, big eye, big mouth
Adipose fin
Centrarchidae – 4 genera, 8 species
Ambloplites
Micropterus
Pomoxis
Lepomis
Micropterus
Largemouth bass
Maxilla beyond eye
Maxilla to middle of eye
Smallmouth bass
Lepomis
Green Sunfish
Pumpkinseed
Bluegill
Ambloplites – rock bass
Rounded pectoral
Solid, no light margin
Percidae – 5 genera, 8 species
Perca
Percina
Sander
Crystallaria
Etheostoma
Sander
White tip
Walleye
More mottled
No-White tip
Sauger
Darters
Rainbow darter
Johnny darter
Fantail darter
Crystal darter
Moronidae (Temperate Basses)
Broken and offset
Yellow bass
Not offset
White bass
Sciaenidae (Freshwater Drum)
Elongated ray
on pelvic fin
Gobiidae (Gobies)
Distinct head
shape differences
Round goby
Tubenose
goby
Gasterosteidae (Sticklebacks)
Uh…count the
spines
Ninespine stickleback
Brook stickleback
Fundulidae (Killifishes & Topminnows)
Vertical
bars on
flank
Blackstripe topminnow
Faint
horizontal
bars on
flank
Starhead topminnow
Ictaluridae (Bullheads)
Yellow bullhead
Yellow chin barbels
Brown bullhead
Mottled
Saw like barbs
Black bullhead
Even color
Ictaluridae (Catfish)
Channel Catfish
Deeply forked tail
Osmeridae (Rainbow Smelt)
Rainbow smelt
Adipose fin
Atherinidae (Silversides)
Brook silverside
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