Lecture Slides Flashcards
1
Q
How is Scope of Ecology linked to Resource management? 5
A
- population growth
- competition between species
- origin/maintenance of biological diversity
- influence of physical environment
- trophic webs ( = feeding webs)
2
Q
Biodiversity in the Ocean?
% of marine species, benthic/pelagic
A
4-14% marine species
- most benthic 98%, 2 % pelagic
3
Q
Phytoplankton
A
plants
4
Q
Zooplankton
A
animals
5
Q
Nekton
A
active swimmers (fish, birds, whales, sealions, etc.
6
Q
Benthos
A
live on bottom (epifauna)
live within bottom sediments
7
Q
West Wind Drift
A
Through April - Sept brings warmer winds, nutrients which supports BC’s coast.
- adds 10% to Oceans Primary productivity
- adds 20% to Worlds Fishery Catch
8
Q
How have bottom trawlers effected the re-introduction of Sea Otters?
A
Bottom trawlers focusing on polluck which has a direct influence on Sea Lion populations which is impacting Killer Whale prey counts which may explain the struggle for the re-introduction of sea-otters (new source of prey for killer whales)
9
Q
How many Estuaries in BC? How do they support a variety of marine resources?
A
442 estuaries in BC
- Support a variety of marine resources through their function as a nursery.
10
Q
What is an estuary?
A
semi-enclosed by land, which is diluted by freshwater runoff
- freshwater input may be small or large.
11
Q
What is the broad ecological importance of estuaries? 5
A
- Highly productive
- habitat for wildlife
- invertebrates - many species in high abundance.
- Nursurt grounds for marine fish “resources”
- migratory pathway for salmon
12
Q
Dungeness reliance on estuaries?
A
Mass tidal migrations
- go up into estuaries to feed during particular seasons.
13
Q
Juvenile Salmon reliance on Estauraries
A
- provide rapid growth
- partial refuge from predators
14
Q
What is the potential link between inbound adult salmon and outbound juvenile salmon?
A
Adult Salmon die providing nutrients for Harpacticod copepods which are a major source of prey for juvenile salmon - assists growth.
15
Q
Benefits of Eel Grass? 5
A
- refuge from predators
- enhance food resources
- reduce local current velocities
- produce oxygen
- stabilize shoreline and stores carbon.
16
Q
What % of commercial fish have been supported through Eel Grass in BC?
A
80%
17
Q
What is a current issue with marine estuaries?
A
- estuaries are economically/industrially attractive due to their unique situation.
- Sheltered harbours & access to rivers (transport)
- Liquid waste disposal, including sewage and industrial effluent.
May lead to:
- Habitat degredation & destruction
- Chemical contamination (pollution)
- In turn creates:
Eutrophication - algae can outcompete eelgrass - Habitat loss/destruction
18
Q
Pacific Herring
- Importance?
A
- Foundation Species
- Dominant forage fish in BC
- Ecological importance but also economic and culturally significant.
19
Q
Recruitment age?
A
age/size of a species that is harvested.
20
Q
Pacific Herring
Where/when do they spawn?
In high biomass years, what can they reach?
A
Spawn December - June in a ‘silver wave’ from California - Alaska
- Discrete short lived spawn events along 450 - 600km BC coast each year.
- Can reach aggregations of 1million adult herring spawn per - ha (in high biomass years)
21
Q
Link between Bears and Herring
A
Black Bears consume herring eggs
- similar timing between spawn and emergence from dens
22
Q
State of Herring in BC
- how was the data collected?
A
Acheological data suggesting information on abundance, distribution and variability.
- Archaeological data came from midden deposits (areas where FN disposed of bones, shells and other food sources)
23
Q
Archaeological Data?
A
- Shape based bone identification (family, genus, species)
- Quantification (number of identified bones, abundance is relative)
24
Q
Significance of Salmon?
A
Salmon effect food webs across ecosystems.
25
Relationship between Bears, Salmon and the terrestrial environment?
Bears are direct consumers of salmon.
- Bears are primary vectors into the forest.
- Forage in daylight and darkness
- Typically consumed brain, roe and dorsal muscle
- Transfer up to 100m
- When salmon are available and abundant bears leave a large portion of carcass that is consumed by multiple scavengers.
26
what influences how far Bears take fish into the terrestrial environment?
How far have they been known to transfer salmon?
distance predicted by energetic reward: salmon density, fish species, sex and size, bear density and habitat.
- up to 100m
27
Why are Chum salmon taken into the forest more than pink by bears?
- due to their size and fat (greater energetic reward)
28
Other vectors of salmon into the forest?
animals?
Natural processes?
wolves, mustelids, eagles
- carcasses, urine, feces and guano
- flooding and groundwater flow.
29
How many vertebrates eat salmon?
39 species (8 mammals, 2 amphibians, 29 birds)
30
15 N? Where is it found?
How is it brought into terrestrial environment?
What can it inform us of?
- How?
Found in marine environments, salmon in particular.
- brought into terrestrial environment from migration of salmon upstream and decomposition of salmon in terrestrial environment.
- Eaten by Fly Larvae, Burying beetles and a range of other animals.
- It can inform us on historical salmon abundance through identifying amounts of 15 N in tree ring size, etc.
31
What are some N-rich indicators and N-poor indicators?
Identified through plants
- N- Rich: Salmonberry, Foamflower
- N - Poor: Blueberry, Red huckleberry, Salal, Deer Fern.
32
Do Salmon subsidies increase or decrease plant diversity?
Salmon decrease plant diversity.
33
Summary Information: Just look at it.
```
Resource subsidies can structure the
ecology of recipient communities
• Salmon impact terrestrial biodiversity:
plants, insects, vertebrates, salmon
themselves, people
Summary
•Shifts in process: invert breeding,
vertebrate predation, riparian plant
community structure and diversity
• Enables predictions of potential
management targets and how
ecosystems may respond
to changes.
```
34
Resource definition?
| Who uses resources?
means of supplying a want or deficiency
| - everything living uses resources - among and between species.
35
Why and how does over exploitation happen? 4
1) Wealth from resources = social and political power, which promotes increased exploitation
2) Scientific understanding limited by lack or controls/replicates (scientific managment of 'optimal' exploitation perspective) - unable to see full extent
3) Complexity of Systems precludes a reductionist approach - so trial and error is needed
4) natural variation (in abundance) masks over-exploitation, often until severe & irreversible.
36
Case Study of Over exploitation in Columbia Basin
- what about recovery efforts?
Pacific Salmon have declined dramtically over last 150 years in Columbia basin - direct result of resource overexploitation and development of the river.
- Extensive recovery efforts have been unsuccessful
- Major threats were:
- harvest, habitat degradation, hydro power and hatcheries.
37
Hatchery produced fish have negatively affected salmon recovery in three ways:
1 - artificial production has taken resources away from other recovery efforts.
2 - Artificial production leads to competition for food and habitat between wild and hatchery fish.
3 - Direct genetic effects can occur when hatchery fish breed with wild fish. offspring have greater mortality.
38
According to Ludwig: How can we avoid patterns of repeated over-exploitation? 5
We must manage humans, not the resources.
1 - study/manage human motivation
2 - act before scientific consensus is achieved
3- - Expect scientists to identify problems not remedy them.
4 - Distrust claims of sustainability (history repeats itself)
5 - Confront uncertainty and include it in management plans.
39
What was the previous outlook on the state of the oceans?
the sea viewed as inexhaustible.
40
Whats so different about us "Human Predators"
- human population explotion
- advanced technology (increased efficiency)
- advantage of fossil fuels
- subsidies from terrestrial foods (agriculture)
- specializations and global trade - not linked to one or few species/food types.
41
```
World Dependence on (use of) fish:
Protein supply?
-how many use as main source of protein?
-where is its use highest?
-how much is harvested annually?
- common uses?
```
15% world protein supply
- 1 billion use as main source of protein
- use is higher in coastal areas
- 95 million tons directly from saltwater/freshwater environments.
- most used for food but increasing in animal feeds etc.
42
Status of Wold Fish Stocks
- % significantly depleted?
- % fully exploited or meet target sustainable yeilds
- % underexploited
28% - significantly depleted or overexploited
- 47% are either fully exploited or meet target maximum sustainable yeilds
- 24% of global fish stocks are under-exploited.
43
CPUE
Catch per unit effort
44
Fisheries Consequences: Shrinkage
- mean fish lengths in a population shrink
| - reproduces at younger ages and smaller sizes.
45
Large predatory fish biomass is be only about .... % of pre industrial levels (sharks, skates, rays and marlin)
10%
46
How has human expansion led to altered ecosystems? 5
```
1 - Fishing
2 - Pollution
3 - Mechanical Habitat destruction
4 - Introductions
5 - Climate Change
```
47
How might recent fisheries data be misleading?
Earliest data on fish stocks may already be on over exploited populations.
48
Why should fisheries management use historical data in centuries versus decades?
- provides the missing baseline for restoration efforts
| - raise the possibility that many more marine ecosystems may be vulnerable to collapse in the near future.
49
The Allee Effect
small populations sizes lead to proportionally increased rates of predation, reduced mating success and reduced fertility
50
Problems that Prevent Recovery (the resources)
- Inter-specific competition and natural predation
| - The Allee Effect
51
Problems that Prevent recovery (humans)
- slow response by managers to address depletion
- inability to reduce anthropogenic mortality to zero
- selective harvesting
- Public/user-group perceptions that are unsupported by science that delay or alter the nature of the managerial response - (links to Ludwig model)
52
Selective harvesting
the largest most successful individuals are targeted whereas those with lower fitness stay in the population
53
What is needed with Uncertainty?
needs to be incorporated into fisheries management models (i.e. there is a lot that we don’t know)
54
Fishing down food webs
Humans started harvesting the highest trophic levels, as those target species declined in population we continued harvesting the next trophic level.
55
Lessons
| - conclusion
Commercial species cannot be managed in isolation from the
ecosystems that they occupy
Humans must be considered part of ecosystems and the
biosphere, subject to the same natural laws and benefiting
from the same supporting services as other species
Uncertainty must be incorporated in Fisheries management.
56
In terms of selecting prey, how are wild animals different from humans?
non-human predators target the juvenile prey primarily while humans generically target the adults.
57
Humans kill carnivores ... faster?
| Humans kill fish marine species ... faster?
carnivores 9x
marine fish 14x
58
Main 3 target goals for rebuilding global fisheries
- maintain biodiversity
- maintaining high catch
- maintaining high employment
59
Sustainable exploitation as conceived by humans 3
- exploit at rates which aim to maximize yields over the long run
- MSY Maximum sustainable yeild
- target adult prey, freeing up resources for juveniles to grow quickly
60
Sustainable exploitation as demonstrated by nature 2
- primarily target juvenile prey
| - exploit adults at low rates
61
How have humans escaped limitations imposed on other predators? 5
- Evolutionary - fishing & hunting behaviour/technology render many anti-predatory adaptations of limited use.
- Behavioural - search and detect - lots of technology to assist. - pursuit and capture (guns and traps make it easy) - handling and consuming - can take as much as we want, not limited by mouth size/strength.
- Ecological - (hyper) specialized individuals - agriculture subsidy decouples humans from dwindling prey populations.
- Economic - low prey abundance can fetch higher prices and drive more aggressive exploitation.
62
In terms of watching our selves as super human predators what can we do?
- use natural predators as models of sustainable exploitation
63
Why might humans be considered super predators? 3
- kill at higher rates than natural predators, specifically large carnivores and fishes.
- target large, reproductive aged adults rather than juveniles.
- have escaped limitation imposed on natural predators.
64
Law of the Sea 1978
- recognition?
- Introductions of?
- recognition that the sea's resources were not inexhaustible
- introduction of the Canada Pacific EEZ (200 nm limit for management)
- the need to have tools for international standards for management limits
65
Decline in Fieldwork?
| reasons? 3
- expensive
- biology is time consuming
- computer modeling is cheap and fast
66
How Fisheries Science sees marine resources
Recruitment + Growth = (Exploitable Biomass) = Natural Mortality - Fishing Removals
67
In terms of models whats a good approach to use when selecting a model?
- all models are wrong. Try to use the least wrong one.
68
Stock/Recruiting Modeling is used to determine..?
Used to determine how much of a stock to exploit and much to allow to "escape" to recruit later over.
69
The problems with fisheries models (Theoretical Problems)
- do not account for changing environmental conditions
70
The problems with fisheries models (Practical problems)
Despite being very common, these models have a poor track record. Man enormous fish stocks have been carefully managed to near extinction by the use of these models. (eg. atlantic cod, anchovy, salmon)
71
Uncertainty in Management
- what errors can occur? 4
- what do most errors refer too?
- Why is uncertainty important?
1. Process error: natural variability
2. Observation (measurement) Error: INaccuracy/imprecision of measurements
3. Model Selection Error: use of "more wrong" model
4. Implementation error: failure to apply policy, or policy to work well.
- Most errors refers to uncertainty, not mistakes.
- important because consequences of ignoring uncertainty can be great
72
Mortality Limit
vs Mortality Target
- what occurs between them?
Mortality Limit:
- from biology of species
- has Process error about it; nature is variable
- our estimate adds observation error; hard to measure basic population parameters (#s, reproduction) well
- exceeding it should be avoided if you do not want population declines.
Mortality Target:
- set by management (how many are allowed to be killed)
- has implementation error about it
- mortality expected to fall above and below.
- The two are often used interchangeably in wildlife management, but are fundamentally different.
73
How is total mortality target/limit calculated?
(Population Estimate x Annual Allowable mortality) - Estimated unreported mortality.
74
Female mortality target/limit?
0. 3 x Total Target
| - only 30% of female pop may be hunted.
75
What are the 2 components to Uncertainty?
| - Component 2 is large, recommend just viewing answer.
Component 1 - Our Audit (to assess implementation error)
- Difference between allowable (target limit) vs reported (actual) human-caused mortality
Component 2 - Simulations - Confronting Uncertainty
76
Target/Limit equation?
Target/Limit = (Population estimate x Annual Allowable Mortality) - Unreported
77
How might someone simulate limits?
Simulate limits by randomly varying each parameters within ranges of uncertainty
- repeat 1000 times to create distribution of LIMITS for each population unit.
78
Confront Uncertainty Part A: How does process/observation uncertainty in population parameters propagate to uncertainty in mortality limits?
- Varied Parameter 1: Population Estimates
- Varied Parameter 2: Annual Allowable Mortality (what proportion can we kill to ensure the population will not decline.
Varied Parameter 3: Unreported mortality
79
Confront Uncertainty Part B: Simulations to confront Implementation Error
- implementation error similarily follows a distribution
| - constructed from historic relationship between allowable and reported mortality.
