446 Aquatic Ecology Flashcards Preview

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Flashcards in 446 Aquatic Ecology Deck (279)
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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