Midterm Flashcards
1
Q
How is ecology linked to resource management?
A
- Populations grow
- Species competition
- Biodiversity maintenance
- Trophic feeding relationships
- Influence of physical environment
2
Q
What is biodiversity in the ocean like? (3)
A
- Of discovered world species, marine species =4-14%
- Likely underestimated
- Most are benthic
3
Q
How are marine organisms classified?
A
By lifestyle
- Plankton float (phytoplankton and zooplankton)
- Nekton swim (fish)
- Benthos live on bottom (epifauna and infauna)
4
Q
5 major oceanic fisheries areas
A
- West coast North America
- Peru coast
- NW Africa
- SW Africa
- Ethiopia
5
Q
Role of whales in nutrient transport
A
- Deep divers bringing up P via their feeding
- Their poop floats, fuels phytoplankton
- Declines in whales have caused this nutrient pump to decrease (24% historic value)
6
Q
Why are kelp forests important?
A
- Highly productive (in nutrient and light-rich waters)
- Structure to support species
- Bring nutrients from marine to terrestrial land (birds eat kelp)
7
Q
Animals involved with kelp forests
A
Sea cows -> sea otters -> urchins -> kelp
8
Q
Explain top-down control of kelp forests
A
Pre-contact: otters each urchins eat kelp
Post-contact fur trade: urchins overgraced kelp forests
Re-introduction: otters controlled urchin population
9
Q
Why were whales blamed for declines in otters?
A
- lost their normal diet of harbour seals and sea lions ->adapt
- We overfished large fish for whales to eat
10
Q
What is an estuary?
A
Portion of ocean semi-enclosed by land and diluted by freshwater runoff (embayment)
11
Q
Characteristics (benefits) of estuaries (6)
A
- Nutrients from rivers = highly productive
- Wildlife habitat
- Nursery for marine fish
- Migratory path for salmon
- Refuge from marine predators
- Dungeness crab mass tidal migrations
12
Q
CPUE
A
Catch per unit effort
- A proxy of abundance
13
Q
osmoregulation
A
adapting to saltwater
14
Q
Explain the relationship between adult chum salmon and chum fry…thanks mom and dad!
A
- Adult chum die and fertilize algae (Ulva) in fall migration
- Copepods eat Ulva, chum fry eat copepods!
- “Conveyor belt”
15
Q
Why are estuaries economically and industrially attractive?
A
- Sheltered harbours and river access = transport
- Fishing and recreation
- Liquid waste disposal
16
Q
What are estuaries vulnerable to?
A
- Habitat degradation/destruction
- Chemical contamination
- Depletion of fish
17
Q
Characteristics of eelgrass
A
- Sub-tidal, adjacent to estuaries and shoreline
- Worldwide in temperate and tropical seas
- Soft-sediments
18
Q
Benefits of eelgrass (5)
A
- Refuge from predation
- Enhance food resources
- Reduce local current velocities
- Produce Oxygen
- Stabilize shoreline and stores carbon via underground biomass
19
Q
Foundation species in coastal food webs
A
Pacific herring = prey for other animals
20
Q
Why are Pacific herring declining?
A
Climate-induced ecological changes in: - Predator distribution - Disease Overfishing Rebound of marine mammal predators
21
Q
Why did herring populations collapse in 1960s?
A
- Increased fleet efficiency
- Reduction fisheries (turning herring into oil and fertilizer)
- Poor recruitment
22
Q
What happens to eelgrass?
A
- Eutrophication causes algae to outcompete eelgrass
- habitat loss
23
Q
Who is Gail Shea?
A
Federal Fisheries Minister
- Approved the reopening of commercial roe herring fisheries on First Nations land
- Ignored recommendations from DFO scientists (2013)
24
Q
The key ecological role of Forage fish (AKA HERRING) (3)
A
- prey for lingcod and salmon
- key position in food webs
- Few species, but high biomass
25
Shifting baseline syndrome and fishery scientists
- Each generation of fisheries scientists accepts baseline that occurred at start of their careers
- Uses this to evaluate change
26
Recent declines in salmon numbers according to Schindler (3)
- fishery exploitation
- habitat loss
- hatchery practices limiting "conveyor belt"
27
Why is the herring egg nesting related to "New Year" to the Heiltsuk?
- Least amount of photosynthetic and animal activity in months prior
28
Salmons accumulate over 95% of their biomass where?
OCEAN!
29
Who eats salmon carcasses and eggs? (4)
- Benthic invertebrates, fish, bacteria, primary producers
30
Two nutrients derived from salmon
P and N
31
How are salmon ecosystem engineers? (4)
Dig nests (holes)
- alters sediment comp
- disturbs benthic communities-> predators eat them
- Changes water and oxygen flow ->increased egg survival
- increases silt export
32
How do salmon derived nutrients enter terrestrial ecosystems? (5)
- Terrestrial predator consumption
- Birds and scavengers
- Floodplains depositing carcasses
- Subsurface water flow to riparian zones
- Aquatic bugs -> riparian zones
33
What parts of the salmon do bears eat?
- Brain, roe and dorsal muscle
| THEY ARE PICKY
34
Greater energetic reward: Chum salmon vs Pink
Chum salmon are larger and fattier, so bears bring them into the forest more frequently
35
Vectors for salmon nutrients to the forest (4)
Primary: Bears
Secondary: wolves, eagles
- faeces, carcasses
- Groundwater flow, flooding
36
HIRMD
Heiltsuk Integrated Resource Management Department
37
Nitrogen rich indicator
Salmonberry
38
Nitrogen poor indicator
Blueberry
39
Missing indicator in Salmon forest story
Bushes!
| - fertilized with salmon remains on sides of waterfalls
40
How do salmon subsidies shift plant communities
Decrease plant diversity
- Nitrogen rich indicators outcompete nitrogen poor indicators
- This means more diversity when soil is nutrient poor
41
Three periods of human impact on marine ecosystems
Aboriginal: subsistence exploitation
Colonial: foreign mercantile powers
Global: intense geographically pervasive exploitation
42
Bottom-up effects on estuaries
increases in P and N from fertilizers causing planktonic primary production -> eutrophication
43
When and How does overexploitation happen? (4)
- Wealth and power, promotes further exploitation
- Scientific understanding limited, lack of controls
- System complexity
- Natural variation masks over-exploitation
44
Major threats to salmon in the Columbia River Basin (4)
- Hatcheries
- Harvest -> first to depress salmon
- Hydropower
- Habitat loss
45
How did Columbia River Salmon harvest get out of control? (3)
- Short-term economic benefits > long-term conservation
- Poor enforcement of restrictions
- Limited salmon biology knowledge
46
Habitat degradation and Columbia River Salmon: 4 mechanisms
- Logging
- Agriculture
- Livestock grazing
- Mining
47
What is the influence of riparian vegetation on salmon physiology?
- Vegetation covers water reducing temperatures
- Human land-use reduced vegetation, water temps 2 degrees higher than historical levels
- Affects salmon metabolism and shelter
48
Effects of hydropower dams in Columbia River Basin (3)
- Reduces spawning habitat
- Changes flow conditions
- Alters habitats
55% of historic spawning habitats are blocked by dams.
49
Fish ladders
An example of an effective technological solution for adult salmon passage
50
The problem with hatcheries (3)
- Takes away resources from other recovery efforts
- Competition for food and habitat between wild and hatchery
- Genetic effects with cross breeding = unsuccessful
51
Ludwigs principles
- Study human motivation and manage it -> GREED
- Act before consensus is achieved
- Expect scientists to identify, not remedy problems
- Distrust sustainability claims -> history repeats
- Confront uncertainty in management
52
What is so different about us human predators? (4)
- Geographic range
- Ability to preserve and store
- Seek surplus -> economics
- Technology
53
Predator-prey flow chart
Search->detect->pursuit-> capture
| - Each step theres an opportunity to escape
54
Status of world fish stocks
a third are significantly overexploited
55
Problems that prevent recovery: the resources
- Natural predation
- Interspecific competition
- Allee effect: small pop sizes = increased predation, reduced fertility
56
Relationship between Harbour seals and Chinook salmon
- Herring and hake are seals primary prey, salmon isnt
- Hake eats salmon smolts
- So seals actually help keep salmon alive
57
Problems that prevent recovery: humans
- Slow response to address depletion
- Inability to reduce mortality to zero (by-catch continues)
- Always hunting BOFF
- Lack of consensus
58
To understand how fisheries is managed, need to know about one number...
Total allowable catch (TAC)
59
What is the law of the sea?
200 mile limit for management
60
Stock equilibrium depends on the balance of what four factors?
( Recruitment + growth ) - (Natural mortality + fishing removal)
61
Why is the population growth rate low at the start?
Few fish in population, but lots of resources per fish
62
Why is the population growth rate low at the end?
Lots of fish in population, but less resources per fish
63
Where is carrying capacity on the graph?
At the very end
| - no further growth is possible
64
What happens in the middle of the graph?
- 1/2 carrying capacity also Nmsy
| - population size with the highest growth rate
65
Where do we want the population size?
Lower than the carrying capacity so positive growth rate is ensured
66
What is SR?
Stock-Recruitment
| - a model showing how much fish SHOULD be added to the population based on previous year stocks
67
Problems with fisheries modelling and SR models
- poor track record
- many fish stocks fished into near-extinction with models
- decline in field work
68
Why are grizzly bears ideal for assessing uncertainty in wildlife management?
- Limited demographic information
- Life-history characteristics (long-life span, low reproductive rates, slow pop growth)
- Very vulnerable to population declines
69
Define uncertainty
Measure of our confidence in a measure
| - i.e. precision
70
AAM
Annual Allowable Mortality
| - number allowed to be killed by humans each year, excluding unreported mortalities
71
What does the red in the graph equal?
Proportion of cases where observed mortality exceeded simulated limits
72
Limits vs targets
- Limits are what you don't want to exceed
| - Targets are what you aim for, knowing you might miss
