Bio 346 - Freshwater Eco. (Chpt 26) --> Fish and Water Birds Flashcards
1
Q
What do aquatic birds exert and important effect on?
A
The abundance and community structure of macro-invertebrates and fish
2
Q
What are the greater size I’m most fishes associated with?
A
- Greater longevity (life expectancy)
- Slower biomass doubling time
- Much higher mobility
3
Q
How many inland fish species are there? And what are the 2 groups they can divide in?
A
- 11,000
- Can be divided into groups with jaws or without jaws
4
Q
Where do the air-breathing lung fishes live?
3 things
A
- High temp
- Low latitude wetlands
- Likely to become hypoxic or anoxic
5
Q
What do the teleost fish behaviourally respond to?
A
Low dissolved O2 [ ] by migration of local movements
- Die if DO is below species-specific minima
6
Q
Different parts of the world have different fish because of what 3 things?
A
- Environment
- Competition
- Predators
7
Q
What are the number of species affected by? (4 things)
A
- Latitude
- Altitude
- Dissolved organic carbon (DOC)
- Total Al [ ]
8
Q
What does life history refer to? (6 things)
A
- Where a species lives
- How it feeds
- Food preferences
- Growth
- Mortality rates
- Behaviour
9
Q
What percent is the mortality from eggs to larvae?
A
Greater than 99%
10
Q
Cohort
A
Number of fish of a given age
11
Q
Year-Class strength
A
Number of fish spawn during single season
12
Q
Why do young fish commonly change habitats?
3 things
A
To reduce the risk of…
- Predation
- Cannibalisms
- Competition for food or habitat
13
Q
Where do fish like to live?
A
Tend to live in selective vegetated inshore areas that provide better protection for predation compared to open waters
14
Q
What effect of age-0 fish have? (2 things)
A
- Abundance of zooplankton prey
2. Alters species composition and size distribution
15
Q
Why are some cohorts strong and some weak?
A
Temporal or spatial match between larvae and abundance of prey or predators during “crucial period”
16
Q
Crucial period
A
When larvae have absorbed most of egg sac and are feeding independently
17
Q
Food limited
A
Density- dependent growth
18
Q
Food not limited
A
Density independent growth
19
Q
Low water
A
Growth arrested
20
Q
High water (flood)
A
Growth, reproduction
21
Q
Poor flood
A
Poor growth, no reproduction (stunted)
22
Q
When is survival the highest?
A
When food is abundant and predation is low
- Competition must also be considered
23
Q
What cab high survival rate lead to?
A
Stunting
24
Q
Stunting
A
To stop, slow down, or hinder the growth or development of species
- Poor population growth
25
What are 5 determinants of fish growth?
1. High latitude
2. Strong seasonality in temp
3. Irradiance
4. Resource ability reflect in seasonality variable growth
5. Flood season
26
What are seasonality in growth at low latitudes often linked to? (3 things)
1. Seasonal floods
2. Drought affecting habitat
3. Resource availability
27
What are 2 ways to measure growth?
1. Mark and recapture
| 2. Inner ear bone rings (otoliths)
28
Larger fish grow at what kind of rate?
Slower rate
29
Production (P) from biomass (B) does what with size?
Decrease
30
What does P:B ratio define?
Biomass growth rate
31
What can differences in ratios indicate? (3 things)
Differences in...
1. Productivity
2. Genetics
3. Species-species/species/enviro interactions
32
What happens to biomass and density as fish size increases?
Decreases
33
How can you determine structure of population?
Multiplying P:B ratio of each cohort by biomass density
34
What age of fish has a higher specific feeding and respiration rates?
Younger fish
35
What re young fish a major source of?
Regenerated nutrients through nutrient excretion
36
Fish exert what kind of effect?
Top-down (predation) and bottom-up (nutrient supply)
37
What are 5 ways you can estimate population in inland waters?
1. Traps
2. Gill nets
3. Seines
4. Trawls
5. Poison all the fish
38
What does electroshocking do?
Temporarily immobilizes the fish so they can be scooped up for estimation
39
What is echolocating?
An acoustic method that involves sending 1 or more beams of ultrasonic sound waves either downbeat at specific angles from the boat
- Waves from fish are bounced off and detected by the screen
40
What is a + and - thing about echolocating?
```
+ = Easy to track
- = Cant tell the specific species
```
41
What kind of sample size works best for the mark and recapture method?
Small sample size
42
Mark and recapture assume 3 things?
1. 100% random mixing (all have the same probability of getting picked)
2. Same mortality (the tags don't increase or decrease of survival)
3. No immigration on emigration
43
What do they use scientific surveys for?
Measure population size to determine how much of a population can be fished
44
Whats one way to look at abundance of fish?
Catch per unit effort (CPUE)
45
What does CPUE stand for?
Catch per unit effort
46
Traditional model
View each population has separate entity that can be modelled independent of competitors, predators, resources and environment
47
What is the traditional model useful?
When fish stocks are large, stable and not overfished
48
Growth over fishing
Modest overfishing can permit rapid recovery when fishing pressure is reduced
49
Negative effect of traditional models
They lack predictive power when overfishing of larger and most producing of individuals cause major change in population structure
50
Biological Overfishing
this type of overfishing causes significant chains to energy flow efficiency and food web structure
- Major problem in inland waters
51
What are 6 things fisheries management includes?
1. Setting size and quality (bag) limits for individuals in recreational fisheries
2. Restrictions on fishing gears
3. Restrictions on capture and retention of particular species during certain critical periods
Eg) Breeding season
4. Setting fishing quotas in commercial fisheries
5. Limiting number of commercial fishing boats
6. Selectivity stocking hatchery reared fish
52
Community fish biomass increases with ___ and decreases with ____
- Increases with trophic status
| - Decreases with nutrient supply declines
53
What happens to TP as total biomass decreases?
Decreases
54
Production
Elaboration of new tissue biomass over a time interval
55
Allen curve
Is a way of estimating the production and yield
| - Plot a mean number of fish against mean body size and measure area under the curve
56
What are 3 things that production is strongly correlated with?
1. Population biomass
2. Weight of largest size-class of fish in population
3. Temperature
57
As fish production increase, what happens to biomass?
Increases
58
Temperature has what kind of effect on protection and why? (+ or -)
Positive and at lower latitudes cause it is more favourable and the growing seasons are longer
59
Substantial fish production will be higher for what size of species?
Smaller
60
What does MEI stand for?
Morphoedaphic index of yield
61
What does MEI use?
Uses ratio of total dissolved solids (TDS) to mean depth (Z) as a surrogate for population yield of species
62
What is mean depth a good predictor for?
Fish yield
63
What is MEI used for? (3 things)
Quick approximation of the yield of...
1. Lakes
2. Reservoirs
3. River wetland systems
64
What are 8 things mean depth effect?
1. Distribution of organisms
2. Lake stratification
3. Light climate
4. Relative size of littoral zone
5. Water temp
6. Flashing rate
7. Nutrient supply
8. Catchment
65
What does a modest increase in resource availability allow?
Higher fish production without changing composition
- Not the case when nutrients produce hypoxia or anoxic hypolimnia or when phytoplankton abundance is sufficient to cause disappearance of submerged macrophytes
66
What can an increase in eutrophication do?
Shift fish community to be comprised of greater zooplanktivorous fish biomass, lower % of piscivorous fish
67
High transparency is incompatible with what?
High fish production
68
Who much of the inland yield is for agriculture?
50-70%
69
What species dominate worldwide?
Carp species
70
Aquaculture
Farming of aquatic organisms
71
What are the 4 types of aquaculture?
1. Extensive
- Relatively natural conditions
2. Semi-intensive
- More controlled conditions, diet supplement, high stocking densities
3. Intensive
- More intensive management and additional feeding (often monocultures)
4. Hyperintensive
- High value species at high densities in cage
- All aspects are controlled
72
What culture is aquaculture waste production best studied?
Hyperintensive culture
73
When are outputs the greatest? And what are the outputs?
- Greatest in the spring and summer when feeding and temp are the highest
- Outputs are organic matter and nutrients
74
7 ways fish farming affects limnology through:
1. Water quality
2. Destruction of good habitat
3. Removal of young fish for culture
4. Introduction of exotic species
5. Genetic effects
6. Disease and parasite introduction
7. Raising piscivorous fish require large input of wild fish for feed
75
What is affected by water birds richness, biomass and composition?
1. System morphology
2. Littoral vegetation
3. Trophic status
76
What happens to species richness with increase in system size?
Increases
77
Where is birds density productivity most highest?
In the littoral zone
78
What is the riparian zone (land-water interface) important for? (4 things)
1. Feeding
2. Resting
3. Breeding
4. Hiding
79
Systems with long shorelines relative to open water have what?
High abundance and biomass of birds
80
What kind of relationship is between tropic status, bird numbers and biomass (+ or -)
Positive
81
What is large scatter in data caused by? (6 things)
1. Human disturbance
2. Nearby size of wetlands
3. Underwater slope
4. Anoxic area
5. Variation in dominant predators
6. Competition
