A look forward
Grades
Regular exams – 300 points (200 completed)
Final exam – 150 points
Abstracts – 50 points
Self-guided field trips – 50 points
Total – 550 points (200 completed)
A = 550-495, B = 440-494, C = 385-439, D =
330 – 384, F < 330
Stocking
Outline
•
Background
•
Types
of stocking
•
Introductions
•
Maintenance
•
Supplemental
•
Biomanipulation
Readings and
Assignments
•
Ch.
10 (226-239)
Fish culture and
stocking of sport fishes
1)
First
hatcheries in U.S. started in mid-1800s
2)
Currently
2.5 billion fishes stocked annually in the U.S. and Canada
3)
Outcome
of stocking programs has been quite variable
a)
Successes
(e.g., striped bass, Gila trout)
b)
Catastrophic
failures (e.g., common carp)
Reasons for
stocking fishes
1)
Enhancing
condition of a fisheries resource
2)
Creating
fishing opportunities not supported by wild fish populations
3)
Biomanipulation
a) E.g., controlling aquatic vegetation or benthic fishes
4)
Providing
food base for predators
5)
Facilitate
recovery of endangered populations
6)
Public
perception!
Example: National
Fish Hatchery System (USF&W)
1)
Established
in 1871 by Congress
2)
Original
purpose of National Fish Hatchery System
a) provide additional domestic food fish to replace
declining native fish populations
b) replace fish that were lost from natural or human
influences (over-harvest, pollution, habitat loss due to development and dam
construction)
c) establish fish populations to meet specific management
needs
d) provide for the creation of new and expanded
recreational fisheries opportunities.
3)
Current
goals of National Fish Hatchery System
a) Restoring and maintaining native fish populations
b) Mitigate for the effect of Federal water development
projects
c) Recovery efforts for threatened and endangered fish
species
d) Providing leadership in developing new fish culture
technologies and fish health strategies
Introductory
stocking
1)
Release
of fish or wildlife into a new or renovated body of water
Number of species
introduced into US
Origin of
Introduced Fishes in the US
Considerations for
stocking introduced species
1) Will the new species compete with existing,
established stocks?
2) Will the new species prey on existing fish?
3) Is the new species suitable for the type of fishery?
4) Are the habitat and environmental conditions suitable
for the new species?
5) Why is the species not already present?
6) In older waters, was the species present before or has
it been introduced before?
7) What will the impact of the new species be on the
habitat and ecology of the water?
8) Genetic effects of introduced species?
Maintenance
stocking
1)
Stockings
made to sustain a population that has limited or no natural reproduction
a)
Spawning
habitat degraded or not adequate
2)
Put
and take fisheries
a) E.g., cost benefit of Lake Watonga trout stocking
program
Supplemental
stockings
1)
Made
to augment a naturally reproducing population
a)
Walleye
stocking in Minnesota more successful at increasing abundance in maintenance
stocking than supplemental
b)
Suggest
avoid supplemental stocking
Biomanipulation
1)
Improve
water quality
a)
Piscivore
to control 2o consumer
b)
Piscivore
to reduce benthic fishes
2)
Remove
vegetation
a)
Grass
carp to remove macrophytes
3)
Elimination
of biota
a)
Wipers
to reduce gizzard shad
b)
Walleye
to reduce bullheads
Stocking
guidelines
1)
Management
plan
a) Clearly define goals of stocking
b) Identify resources (e.g., stocking frequency)
2)
Lake
classification
a) Habitat characteristics can guide stocking protocol
b) Adequacy of forage fish
3)
Social
considerations
a) Distribution of fishing effort
b) Economics
i)
Direct impact
ii)
Indirect impact
iii)
Induced impact
– purchase of goods
4)
Evaluation!!!