446 Aquatic Ecology Flashcards Preview

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Flashcards in 446 Aquatic Ecology Deck (279):
1

why study aquatic ecology

aquatic ecosystems & resources critical to human survival, health, well being

2

ecosystem processes

hydrologic flux, storage
biological productivity
biogeochemical cycling, storage
decomposition
maintenance of biological diversity

3

ecosystem "goods"

food
construction materials
medicinal plants
wild genes for domestic plants and animals
tourism and recreation

4

ecosystem "services"

maintain atmospheric gaseous composition
regulate cimate
cleanse water/air
pollinate crops
generate/maintain soils
store/cycle nutrients
absorbe/detoxify pollutants
maintain hydro. cycles
provide beauty, inspiration, research

5

human disturbances affecting coastal ecosystems

1. Fishing, Pollution, Mechanical habitat destruction, introductions, climate change
(fishing always preceded other disturbances, others change in order)

6

inputs and concerns

organic (livestock), fertilizer, rain, pollutants, pathogens, pharma-care, invasive species, nitrate leaching

7

adverse effects of eutrophication

increased biomass of plankton
shifts in phytoplankton (may be to toxic)
increased epiphytes
coral reef loss
decreased water transparency
oxygen depletion
increased fish kills
loss of desirable fish species
reduction in fish/shellfish harvest
decreased aesthetic value

8

chemical characteristics of aquatic ecosystems

nutrients

9

biological characteristics of aquatic ecosystems

foodweb

10

limnology

the study of inland waters - lakes (both freshwater and saline), reservoirs, rivers, streams, wetlands, and groundwater - as ecological systems interacting with their drainage basins and the atmosphere.

11

algal biomass vs nutrient

chl vs. Total phosphorus (TP)
increasing on log scale but large variation above/below the line

12

why measure TP as nutrient load?

most limiting resource

13

high nutrient, lower than expected Chl (algae)

more large fish, preying on large grazers

14

small algae

larger, efficient grazers
larger biomass
larger planktivorous fish
system is more efficient

15

system with lots of small planktivorous fish

prey upon small grazers
larger algae

16

high density of small fish

low density of large zooplankton
higher Chl (algae)
greener water, lower O2

17

small grazer, shallow lake, Chl vs. TP

high productivity, but less than small grazer system in med-large lake- less O2, less insolation, less space...

18

empirical data

observational

19

experimental data

manipulate variable

20

response of lake ecosystem to nutrient loading experiment

same [nutrient], #large fish vary
w/o large fish = small zooplankton = more algae

21

epilimnion

the upper layer of water in a stratified lake, ~constant T, mixed layer

22

lakes with high grazing, low TP

clear water, more light penetration, more heat deeper, larger metalimnion, less steep T gradient, deeper O2 max, photosynthesis can occur throughout metalimnion

23

metalimnion

thermocline, T changes more rapidly with depth than it does in the layers above or below, highest density, layer of 'stuck' algae

24

indicator of water transparency

secchi depth

25

lake with low grazing, high TP

high Chl = low transparency = low O2, higher and smaller metalimnion, less light penetration, steeper T slope in metalimnion, light just barely penetrates meta., photosynthesis cannot occur throughout metalimnion, O2 goes to 0, system is reducing (like saanich inlet)

26

zooplankton size under high fish density

~80% less than 0.2mm

27

zooplankton size under low fish density

~40% less than 0.2mm

28

hypolimnion

the lower layer of water in a stratified lake, typically cooler than the water above and relatively stagnant, ~constant T, O2

29

algae biomass with time

low grazing= increased biomass w/ t
intense grazing = very low slope, barely increasing

30

TP with time

low grazing = increased TP w/ t
intense grazing = very low slope, barely increasing
low grazing = more algae = more TP

31

dissolved P with time

low grazing = very low slope, barely increasing
intense grazing = high slope, increasing

32

why is there higher dissolved P with intense grazing

high grazing = lots of dissolved P b/c not being taken up by algae
size of fish controls [algae] which controls [dissolved vs. particulate P]

33

length of algae as a function of biomass of algae in large grazer system

as biomass increases, size increases (more removed = more nutrients available to the fewer)

34

length of algae as a function of biomass in small grazer system

increased biomass = smaller size (more biomass means higher quantity means less nutrients available to each)

35

algae size and phosphate turnover time

small algae (large grazer system) = slower nutrient turnover = long phosphate turnover time
large algae (small grazer system) = faster Phosphate turnover time

36

when you have large particles, the overall particle load

is made up of more large particles, median is higher
large particles = less small particles

37

add nutrients

overall particle size shift to larger particles
= long phosphate turnover time

38

add nutrients and fish

shift to more smaller particles
= shorter phosphate turnover time

39

so... as average size of plankton declines..

larger slope, uptake efficiency increases, turnover time is shorter
AND transparency declines

40

how changes in biology = changes in physics

thermal structure, penetration of light, accumulated energy/heat content

41

fetch

longest open length of a water body through which wind can blow

42

change in epilimnion with fetch

increased fetch = increased depth of epilimnion (more wind = more wind mixing)

43

downward heating intensity vs. penetration of solar radiation

increasing surface area of water body (fetch) vs. increasing water transparency

44

increasing fetch & transparency

deeper epilimnion, more heat, more energy, greater depth for photosynthesis, more O2

45

role of biology on mixing rate

affects clarity of lake which affects insolation absorption which affects stratification

46

sedimentation, total phosphorus rates highest in

+N (nutrients added, no small fish, large zooplankton)

47

secchi depth highest in

control then +N
deepest when no small fish

48

chlorophyll highest in

+NF (nutrients, small fish, small zooplankton grazers, larger algae)

49

summer O2 profile, control vs. +F

+F higher O2 in epilimnion
lower O2 in metalimnion and hypolimnion
O2 max is higher in water column in +F and goes to 0 with depth

50

summer O2 profile, +N, +NF

+N higher O2 at all depths
+NF goes to 0 in hypolimnion

51

lake St. George

large # planktivorous fish
low secchi depth
smaller daphnia
shallower epilimnion depth
higher TP
higher Chl
strongly eutrophic

52

Haynes lake

less planktivorous fish
deeper secchi depth
deep epilimnion depth
larger daphnia length
lower TP
lower Chl

53

Julian days

continuous count of days since the beginning of the day starting at noon on January 1

54

hypolimnetic oxygen changes with season

oxygen depletion from spring -- summer (lowest O2 with +F)

55

hypolimnetic oxygen chantes in Haynes lake and lake StGeorge

both reach min. in June, S.G. stays at ~0 for rest of summer, H. increases to second max in late July-early August. Lake H. never goes to 0

56

algae size and relative sedimentation rate

small grazer system = short phosphate turnover time = lower relative sedimentation

57

why larger grazer system has higher relative sedimentation

large things sediment more, greater proportion sink, heavier, less efficiently used (P turnover)

58

absolute sedimentation rates

would be higher in small grazer system because there's so much more

59

toxic algal groups

cyanobacteria, dinoflagellates, diatoms

60

problems with algal blooms

toxins, anoxia, habitat loss, recreational loss, health risks

61

anthropogenic P, N to aquatic systems lead to

eutrophication
algal blooms
fatal algal toxins
anoxia- loss of diversity/habitat
proliferation of waterborne pathogens
increased chlorination byproducts in drinking water

62

waterborne pathogens especially important in

tropical/subtropical regions, can be related to cholera

63

forms of land-use

agriculture
farming
waste disposal
fertilizer
harvesting
hydrology

64

effects of N,P loading are different

depending on structure of system
shallow vs. deep
large vs. small fish

65

population growth

increasing pop., more mouths to feed, more land-use required, world fertilizer growth, more N,P loading,

66

obtaining N, P for fertilizer

N atmospherically available, easier to obtain. P not atmospherically available, geological nutrient, limited

67

problem with speed of population growth

available, cultivatable agricultural land is NOT increasing, need GMOs to keep up with pop. increase

68

GMOs to keep up w/ pop. increase

rices that can grow through floods - multiple crops/year

69

problem with GMOs that allow us to increase agricultural yield

leaching soil nutrients, more and more fertilizer

70

population growth and water shortage

water hungry plants and animals (and nutrient loading)

71

examples of water hungry crops

70L/apple
3400L/kg rice
140L/cup of coffee
120L/glass of wine
15,500L/ kg of beef

72

changes in atmospheric NH4

30% increase in urea use as fertilizer (1960-1990)

73

observed relationship between N,P and Chl

positively correlated
nitrogen more tightly correlated

74

eutrophication defined as

excessive growth of algae, often associated with bluegreen and other harmful algal blooms

75

determines types of algal bloom

amount of nutrients, composition of nutrients (TN:TP)

76

N:P ratios for different runoff types

unfertilized field N:P 250
forests 75
rainfall 25
manure seepage 9
sewage 5

77

nutrient composition ratio

dependent on where nutrients come from
dictates algal bloom

78

bluegreen algae associated with what nutrient composition

low N:P ratio (towards the manure, sewage deposits)

79

differential response to increased [P] in N limited vs. P limited ecosystem

N limited systems does not respond as strongly to increased P

80

increasing phosphorus concentration =

increased dominance of cyanobacteria

81

other controls on levels and types of algal biomass blooms

seasonality of nutrient inputs (coastal and freshwater ecosystem)
physical properties of receiving system
structure of foodweb

82

N:P ratio as a control in number of red tides

as N:P decreases, #red tides increases, highest below 16
duration of blooms longer when N:P

83

redfield ratio

N:P
16:1

84

increasing nutrient, increasing algal biomass

responses are not proportional in all systems, dependent on structure of foodweb (small vs. large grazers) and physical structure of ecosystem

85

physical lake structure and response to changes in nutrients

deeper lakes can take more 'abuse' before showing response (less likely to become eutrophic)

86

algae harmful to animals, humans

cyanobacteria (bluegreen)
dinoflagellates
some diatoms

87

types of algal toxins

neurotoxins
hepatotoxins
lipo-polysaccharides

88

neurotoxins

alkaloids, b/g algae
cause neurodegenerative symptoms through disruption in communication between neutrons and muscles

89

neurotoxin examples

anatoxin-a, saxotoxin, neosaxotoxins, Nostoc, Anabaena, Oscillatoria, Aphanizomenon

90

hepatotoxins

peptides
affect liver, cause weakness, vomiting, diarrhea, respiratory blockages

91

hepatotoxin examples

Anatoxin-a, saxotoxin, neosaxotoxins, Nostoc, Anabaena, Oscillatoria, Microcystis

92

Lipo-polysaccharides

cause skin irritation (dissolve skin)

93

neurotoxin bioaccumulation

accumulate in nervous system (cerebral), show up with age

94

fertilizer use and red tides

increased fertilizer use tightly correlated with increased # of red tides

95

TP, TN and toxin forming algae concentration

both positive correlations
steeper increase in toxin forming algae with increased TP then increased TN

96

concentration of microcystin vs. toxigenic biomass

increasing. the more biomass present, the more of the toxic variety

97

microcystin

class of toxins produced by certain freshwater cyanobacteria

98

ubiquity of cyanobacteria

terrestrial, freshwater, brackish, marine, widespread = potential for widespread human exposure

99

β-N-methylamino-L-alanine

BMAA- novel neurotoxic amino acid from cyanobacteria (and many algal taxa around the world), ubiquitous, accumulate and slowly release through time, found in brain tissues of people who die of ALS and other neurodegenerative disease

100

BMAA in guam

high concentration in coralloid roots of cycad trees-- concentrated in fleshy seed-- flying fox forage on seed-- accumulate-- Chamorro people eat them-- die of ALS-PDC. 50-100X incidence rate anywhere else

101

BMAA biomagnification

free BMAA--cyanobacteria 0.3µg/g--- cycad 37µg/g -- flying foxes 3556µg/g -- Chamorro people

102

Chamorro people

highest rate of neurodegenerative disease in the world

103

water categories based on nutrient richness

Oligotrophic- nutrient poor
Mesotrophic- good clarity, average nutrient
Eutrophic- enriched with nutrients, good plant growth, possible algal blooms
Hypertrophic- excessively enriched with nutrients, poor clarity, devastating algal blooms

104

lake Taihu

went from oligotrophic (1960) to eutrophic-hypertrophic in 90's
population growth, livestock growth
toxins produced

105

ALS

amyotrophic lateral sclerosis

106

BMAA exposure in desert dust

soldiers found to have high levels of BMAA, suffering from neurodegenerative disease from Iraq desert pools. dormant until rain season. inhaled, especially around Gulf War.

107

sporadic ALS in Annapolis, Maryland

found to come from Chesapeake Bay blue crabs, BMAA in Chesapeake Bay food web common risk factor

108

fa cai, Mandarin; and fat choy, Cantonese

Nostoc grown and harvested to make soup during New Years celebration. Banned now, mostly artificial, but some still contain Nostoc (BMAA).

109

driving force in aquatic system

foodweb
changes to food web have cascading effects

110

ecosystem productivity depends on

transfer efficiency of nutrients and energy along foodweb- affected by changes in predators and prey- any affects = cascading changes

111

shifts in food web structure and function, implications for

predator/prey effects
contaminant transfer
biodiversity
productivity

112

energy transfer efficiency in small plankton, small fish system

less efficiency transfer

113

predatory invertebrates

comets with small fish for prey, added system complexity

114

food web views

bottom-up - ratio dependent, more inputs = more outputs
top-down - limits bottom up, predators self regulate

115

predator self regulation

eat too much and use up all resources

116

k

carrying capacity of system

117

low k

low resources, nutrients, space

118

predator/prey biomass vs. carrying capacity models

R-O model: predator increase w/ k, prey constant
A-G: both increase but predator growth is smaller than prey growth
Getz: both increase parallel to each other, prey higher
predator self limitation: prey increases, predator constant

119

Fretwell trophic level biomass vs environmental productivity

alternate trophic levels have parallel relationships
level 3 grazes down level 2 which helps increase level 1

120

Fretwell-Oksanen trophic level biomass vs environmental productivity

predators keep prey constant
levels 1&3 parallel increase, 2 constant while they increase
when 2 is increasing, level 1 is constant

121

Ginzburg-Getz-Ardith trophic level biomass vs environmental productivity

all increasing
ratio dependent
highly contradicted system, level can't increase at a ratio dependent manner, would self restrict

122

Persson trophic level biomass vs environmental productivity

looks the same as F-O only 2 trophic levels exist. one is increasing while the other is constant

123

length of food chain

affects accumulation process and efficiency

124

each food web interaction (energy transfer)

- 10-15% of E
shorter food chain = more efficient

125

Menge and Sutherland, views on top down regulation in food webs

physical disturbance shortens food chains, most organisms will shift diet depending on food availability

126

Hairston, Smith, Slobodkin , views on top down regulation in food webs

predator/prey interaction bring in self regulatory processes. predators regulate herbivores, releasing plants to become resource limited

127

Freewill and Oksanen, views on top down regulation in food webs

top trophic levels and even numbered steps below are resource limited, trophic levels odd numbered steps below are predator limited

128

McQueen, views on predator and resource co-limitation in food webs

top-down diminishes efficiency at bottom of food chain, but both affect each other

129

Getz, views on top down regulation in food webs

inference hypothesis- predators interfere with each other- prevent efficient exploitation of resources, prey can increase

130

Mittelbach, views on top down regulation in food webs

predators require different resources as they grow (ontogenetic shift)

131

Lei bold, views on top down regulation in food webs

control of prey by consumer is not always consistent (shifts to less edible species)

132

Sinclair and Norton, views on top down regulation in food webs

starvation-weakened prey become more vulnerable to predation or disease

133

predator negative feedback, self regulation

interference competition
exploitative competition
depletion of nutritious, palatable, accessible prey

134

algal biomass vs. potential productivity, even link system (hypothetical)

2-link (algae, zooplankton), increased productivity will not increase algal biomass

135

algal biomass vs. potential productivity, odd links system (hypothetical)

potential productivity can increase, 3rd link consumes 2nd link and allows 1st link to grow

136

TP, indicator of

productivity

137

fishing down top of foodweb

shifting average trophic level (down)
significant decline in average trophic level of fish catch, average size of fish becoming smaller
crowding down foodweb?

138

how to define trophic level

analyze gut content

139

as average catch increases

average trophic level decreases, Pauley et al., 1998

140

cascading effects of the loss of apex predatory sharks from a coastal ocean

11 species of shark- all declining from overfishing
different species of mesopredators - all increasing
termination of scallop fishery

141

effects of fish in river food webs

one of first experiments on river ecosystem to demonstrate cascading effect of predators on lower trophic levels are consistent w/ observations from other ecosystem (remove large fish, small fish dominant, algal biomass increased, odd/even # trophic level limitations)

142

major change in food web concept theories

foodwebs are not closed systems. local interaction in one ecosystem may reverberate into another.
ex. aquatic system affecting terrestrial

143

aquatic system affecting terrestrial example

fish eating larval dragonfly-- decrease dragonfly abundance -- increase honeybee abundance -- increase pollination
no fish-- pollination significantly decreased

144

shrimp stocking theory

add more food, they will produce more

145

shrimp stocking results

reduced number of spawner, reduces numbers of bears and eagles

146

what happened with the shrimp stocking?

the introduced shrimp (Mysis) come up in water column at nigh and prey on the kokanee/trouts food but stay at the bottom of the lake during the day- reducing fish prey

147

Lake Victoria changes

introduced Nile Perch (1954) to increase European sport fishing; HAD extremely high diversity before; major shift to invasive species, basically replaced natives, loss of diversity and food web interactions

148

stability and diversity

higher diversity = higher stability

149

Haplochromis

zooplanktivorous cichlid, significantly decreased since introduction of nile perch

150

one positive side to nile perch introduction

more protein for Kenyan people

151

trophic downgrading

apex consumers were ubiquitous for my's, extensive cascading effects as diverse as disease, wildfire, carbon sequestration, invasive species, biogeochemical cycles: process, function, resilience

152

trophic cascades: see otter populations

eat sea urchins- sea urchins destroy roots of kelp- kelp bed declines harm many species (home to many species, similar to corals)

153

trophic cascade: sea star

absence of sea star= loss of diversity in tidal community; sea stars increase species diversity by preventing competitive dominance of mussles

154

trophic cascade: Long Lake, Michigan experiment

large mouth bass - prey on minnows-- graze on algae. right side of lake has bass = clear lake, left side has no bass = decrease clarity. bass indirectly reduce phytoplankton, indirectly increase clarity

155

trophic cascade: sharks

without sharks/apex predators don't have complex food web, can't have clear water, can't have coral reefs

156

trophic cascades: Brier Creek

predatory bass extirpate herbivorous minnows, promote growth of benthic algae, alter colour of water

157

trophic cascade: arctic fox

preys on birds, decrease bird population-- decrease nutrient input (poop)-- grasslands turn to tundra

158

trophic cascades: predatory cats

remove large predators-- herbivores increase and 'clean up' forest floor (less leaf litter and forest floor plants)

159

trophic cascade: wolf

wolf-- elk-- more, greener riparian vegetation

160

trophic cascade: wildebeest

eradication of virus-- recovery of native ungulates-- decline of woody vegetation in Serengeti

161

sea otters absent

fish abundance decreased
mussel growth decreased
gulls- diet shift from fish to invertebrates
bald eagles- diet shift-- decrease in mammals, fish; increase in birds

162

trophic cascades: fire

rinderpest (viral) decreases wildebeest which decreases vegetation control which increases fire risk
40% more burn with virus

163

trophic cascade: disease

fishing decreases lobster-- decreases sea urchin density-- increases epidemics
~30% increase in epidemic without fishing

164

trophic cascade: atmosphere

bass decrease minnow, decrease zooplankton, decrease phytoplankton, increase atmospheric C influx

165

trophic cascade: soil

fox decreases seabirds, which decrease soil nutrients

166

trophic cascade: water

spawning salmon decrease particulate suspension, decreases stream particulate load

167

trophic cascade: invasive species

predatory birds decrease non-indigenous spiders

168

trophic cascades: biodiversity

coyotes decrease mesopredators which decrease small vertebrates

169

preceded all other human disturbance

overfishing -- ecological extinction

170

fishing and nile perch

type of fishing determine survivorship (age), survivorship determines prey taken by nile perch

171

nile perch predation on haplochromines

decreasing: no fishing, gill nets, beach seines, gill nets + seines

172

salmon life cycle

freshwater- eggs, rearing of juveniles
estuary- smolt (0-1yr)
ocean- juvenile, growth (1-4yrs)
estuary- returning to freshwater to spawn
freshwater - spawning, death- contribute nutrients

173

importance of salmon in the ocean

orca
harbour seal
commercial fishery

174

importance of salmon in freshwater

sport fishery
cultural fishery
bear, eagle, gull, coyote, otter, raven, crow, trout

175

simplified salmon life cycle

incubation-- fry-- smolt-- adult-- return

176

salmon fry

recently hatched, very young

177

smolt

young salmon, ~2yrs, ready to return to sea, changes to system for saltwater life

178

salmon return related to

size of smolts

179

~2inch smolts

4-8% return rate

180

~6inch smolt

10-20% return rate

181

smolt weight

is significantly decreased with increasing density, there is a limit to how many fish a system can produce (carrying capacity)

182

salmon and nutrient-foodweb dynamics

more nutrients-- larger algae-- small/inefficient grazers-- low growth, small smolts, low adult return

183

fertilization of lake, 1983

TP increases, algal biomass increases, daphnia size and biomass increase

184

impact of lake fertilization on smolt size

1yr old smolts small increase in size
2yr old smolts large increase in size

185

impact of lake fertilization on fry/smolt density

both increasing

186

fry stocking of lake, 1987

TP, algal biomass drop off, daphnia size and biomass drop, average smelt size drops off, fry and smelt density increase for a few years then drop off, change in zooplankton composition
over capacity

187

smolt size vs. daphnia size

positively correlated
(larger, efficient grazers = larger fish)

188

important factors in the highly variable growth pattern of sockeye smolts

fry density
size of zooplankton
lake features

189

size of 1yr old smolts and total zooplankton biomass

available food is not a good predictor of smolt size

190

size of 1yr old smolts and mean size of Daphnia

quality of food is a better predictor of smelt growth and size

191

smolt size and nutrient levels

smolt size and fry density higher in high nutrient system, but not increasingly so, systems 'level off' in all nutrient levels

192

photic depth vs. turbidity, and colour

photic depth rapidly drops off in both, but quicker with increased turbidity

193

light penetration, clear lake

euphoric depth 16.4m
secchi depth 7.2m

194

light penetration, stained lake

euphotic depth 7.4m
secchi depth 4.3m

195

light penetration, glacial lake

euphotic depth 6.5
secchi depth 1.5m

196

thermal traits, clear lake

max T 14º
mean T 7.8º
heat budget 11.8 kcal/cm^2

197

thermal traits, stained lake

max T 16.2º
mean T 6.9º
heat budget 10.8 kcal/cm^2

198

thermal traits, glacial lake

max T 11º
mean T 5.9º
heat budget 11.6 kcal/cm^2

199

vertical mixing patterns in different lakes

depth as a function of T
heat budget is area 'under the curve'

200

depth vs. T, clear lake

med T at surface, drop off, med T at depth

201

depth vs. T, stained lake

highest T as surface, rapid drop off, lowest T at depth

202

depth vs. T, glacial lake

coldest at surface, T remains ~constant at every depth, winds up being highest T at depth b/c other 2 drop off to lower T

203

Primary production in different lake types

Chl vs. TP
positively correlated, high slope in clear lake
positively correlated, med slope in stained lake
no real relationship in glacial lake

204

glacial lakes

lowest light penetration
lowest T's (med. heat budget)
constant T with depth
higher TP
lower Chl then clear
produces smallest fish and lowest smolt biomass

205

1yr old smolt weight vs. age and different lake types

age vs. weight tightly positively correlated
clear lakes - fish at whole spectrum of the best fit line
stained - ~half way up line
glacial lake- only the lowest part of the line

206

smolt length in lake types

clear 95mm
stained 71mm
glacial 69mm

207

smolt weight in lake types

clear 7.9g
stained 3.3g
glacial 2.6g

208

smolt biomass vs. euphotic depth

clear - positively correlated
stained, glacial - only points at small euphotic depths, euphotic depths can't be very deep in these lakes

209

smolt biomass vs. zooplankton biomass

clear - positively correlated
stained- positively correlated but only goes ~half way up line
glacial - only points at small smolt/zoop biomasses

210

SST shift study, Eastern Bering Sea

2002-2005 warm, 2006-2007 cold
use N isotopes in zooplankton to study shifts in foodwebs

211

Eastern Bering Sea sampling

cruises in sep. 2003, 2007
collected juvenile salmon, forage fish, zooplankton
186 stations
13,000 fish, 600 zooplankton samples analyzed for N, C isotopes

212

juvenile salmon studied in eastern Bering Sea

sockeye, pink, chum, coho, chinook

213

change in abundance of juvenile salmon

in cold years juvenile salmon distribution decreased in all species types
pacific cod abundance increased

214

∂13C tells

where food comes from in relation to shore
more depleted (more - ) = off-shore
less depleted (less - ) = near-shore

215

∂15N vs ∂13C

trophic enrichment of 15N up foodweb

216

algae ∂15N

4-8‰

217

∂15N, inverts.

8-14‰

218

∂15N, forage fish

10-14‰

219

predatory fish, ∂15N

10-18‰

220

why trophic enrichment of 15N?

organisms preferentially utilize the lower molecular weight isotope leading to enrichment of the heavier one

221

∂15N in plankton

must be determined for every group of plankton to set a baseline, then this baseline can be used to determine trophic level in the fish

222

juvenile salmon trophic position above zooplankton

2005 ~2
2007

223

why were juvenile salmon higher in trophic level in warm years

more food available, growing bigger/faster, consuming fish

224

why juvenile salmon lower in trophic level in cool years

less nutrients available, less food available

225

differences in N vs. S Eastern Bering Sea (EBS)

S: large shift in trophic level from warm - cold years
N: little change in trophic level

226

increasing nutrients of a system

may enhance smolt production through enhanced 1º, 2º productivity (but only up to k)

227

survival of smolts

can increase with increasing size of smolts

228

adults returns/recruits per spawner

may increase with increasing smolt size

229

high density of salmon fry

can dampen impacts of nutrients on smolt size and production by:
limiting resources available,
reducing efficiency of nutrient/energy transfer,
reducing growth/survival of fry and smolts

230

anadromous

fish, born in fresh water, spend most of life in the sea and returns to fresh water to spawn. Salmon, smelt, shad, striped bass, and sturgeon

231

management of anadromous fisheries

integrate ecological and fishery science to better understand and quantify linkages between freshwater and marine phases

232

challenges facing sustainable fisheries

-conflicting interests of stake holders and end users
-stocking/fertilization of lakes/streams beyond carrying capacity

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to develop meaningful management models

-synthesize long-term data to determine carrying capacity and relate to spawners and production of smolts
-develop better long-term data on fry/smolt production and relation with adult return

234

upwelling systems

less than 2% of the ocean
contribute 7% to global marine PP
contribute 20% of global fish catch

235

CCS

California Current System
from the top of VI down
wind moves water south, causes upwelling, huge economic value to BC

236

Subarctic Current, Alaska Current

North of VI
boundary between varies in position, strength, and timing throughout the year and year-year

237

current system changes

affect fish catch

238

economic value of upwelling systems

ex-vessel value at least $200million
economic spin-off orders of magnitude larger
sport fishing ~$2billion
recreational, shipping value

239

ex-vessel value

post-season adjusted price/lb for first purchase of commercial harvest, usually established by determining average price for an individual species, harvested by a specific gear, in a specific area

240

Important biological processes in the CCS

basin conditions:
PDO
NPGO
ENSO
local conditions:
upwelling
Temperature
Salinity

241

PDO

pacific decadal oscillation, oscillates between warm and cool phases,
leading principal component of North Pacific monthly sea surface temperature variability

242

NPGO

northern pacific gyre oscillation

243

ENSO

El Niño - Southern Oscillation

244

High PDO effects (generally)

high salmon survival in Alaska
lower salmon survival here and N US (lower nutrients)
inverse production regimes

245

Inverse production regimes

"portfolio effect"
provide stability
diverse stock responses = lower variability overall

246

recruitment

abundance of fish entering a targeted population determined by growth, abundance, and survival

247

classes of study in fisheries oceanography

1.determination of parameters that
define habitats of different life-history stages
2.integrated assessment of the “health” of the ecosystems
3. assessment of
the effects of climate variability on recruitment

248

first few weeks that young salmon spend at sea

appears to be when year class strength is set, critical survival period

249

Oceanic Niño Index (ONI)

3month running mean of SST anomalies in Niño 3.4 region of equatorial Pacific
(5°N–5°S, 120°–170°W).
An El Niño event is defined to occur when ONI > 0.5°C for 5 consecutive months

250

copepod diversity

summer: low- sub-Arctic
waters dominate, naturally
contain low diversity
winter: highly diverse assemblage of subtropical copepods
negative PDO: less diversity
positive PDO: more diversity
indicator/sentinel species

251

ENSO characteristics

large scale climate patterns
warm anomaly across equator
fish that are expected to come back, don't

252

ENSO now

safely say one of the 3 strongest on record
likely to be the strongest on record
~60% chance it will revert to La Niña mid2016

253

NPGO affected by

regional and basin-scale variations in wind-driven up welling and horizontal advection

254

NPGO affects

salinity, nutrient concentrations

255

NPGO fluctuations cause

changes in phytoplankton concentrations and variability up trophic level

256

NPGO now

variability is increasing
bad NPGO year = bad fish stocks everywhere, little-no portfolio effect

257

warm-water copepods

small, not high quality energy reserves

258

cold-water copepods

larger, adapted to survive cool T's, large lipid reserves, more energetic food source

259

effects of local conditions on salmon, primary production

increase Chl = increased resident fish yield
but.. salmon aren't resident, don't appear to be driven by Chl

260

PDO cool phase, copepods

transport boreal coastal copepods into california current from gulf of alaska

261

PDO warm phase, copepods

transport sub-tropical copepods into NCC from transition zone offshore

262

mechanisms that bring copepods to shore dictated by

physics

263

why do salmon care about copepod species

early marine life mortality is size-selective (predation, gape limitation), smolts 99% mortality,
growth in early marine life is critical, large fish = higher survival

264

quality of prey and growth

high quality prey = more energy = grow faster
smolts feeding on low quality of prey reach ~1/2 size of smolts on high quality prey in 1yr
quality vs. quantity appears to drive fish stock

265

linking climate to salmon survival

Bayesian networks- can use quantitative, qualitative, expert opinion, to test various scenarios. provide probabilistic framework in addition to hypothesis testing.

266

testing WCVI chinook

fish tissue samples fall of 2000-2009
stable isotope analysis to geneticallyy ID (make sure local)
remain resident w/i few hundred km of natal stream until winter
analyze stomach content

267

∂13C offshore

depleted (more negative)
low productivity

268

∂13C indicator

strong indicator for salmon survival - can predict how many salmon will return based on ∂13C

269

difficulties of examining isotope records

~months worth of data to distinguish
shifting diet and habitat with growth
interannual effects

270

results of WCVI chinook study

find NPGO to be driving factor affecting survival

271

why does NPGO affect survival

directly impacts ∂13C
indirectly: SST--copepods--zooplankton--∂13C--survival

272

what does PDO affect?

leads to ∂15N (trophic level), not connected to survival

273

effects of changing SST

shift species distribution, bring new species, new copepods, effect salmon species?

274

climate change effects

intensify winds, stronger upwelling - may increase productivity, change migration patterns, affect precipitation patterns

275

effects of changes in precipitation

warm dry summers lethal to salmon stock
truck fish from lake to river/ocean?

276

ocean acidification

CO2 sink
CO2 + H2O -- HCO3 + H
decreasing pH
affect critical life stages
killing VI shellfish stocks

277

jack salmon

Chinooks that return to the fresh water one or two years earlier than their counterpart

278

most consisten eutrophication effects

shifts in algal species composition
increased frequency/intensity of nuisance blooms

279

carrying capacity definition

maximum number of individuals of a given species that an area's resources can sustain indefinitely without significantly depleting or degrading those resources