market squid lobster abalone rockfish sea urchin shark commercial fishery landings in santa barbara
TRANSCRIPT
Market Squid
Lobster
Abalone
Rockfish
Sea Urchin
Shark
Commercial Fishery Landings in Santa Barbara
What is Catch??
• Catch = (Catchability) (Effort) (Biomass)
Catchability is f(skill, technology,…)
Effort is hours, # trawls, … = f(profit, …)
Biomass is the stock abundance
• Profit to fishery = (price) (Catch) – (Costs)
Profit drives effort…
Price = f(market, …)
Costs = f(fuel, distance to port, biomass, …)
Fish & Climate
• Several identified oscillators
– annual, SOI & PDO
–more likely as our data sets are short
• Several mechanisms
– changing upwelling – bottom up - food web control
– spawning habitat changes
• The interaction of time scales are key
– If critical time scales are similar, climate is important
Market Squid Landings
VERY short lived – Egg survival is key – Size specific carnivore
Yellowtail Landings
Long lived - Migrates 1000’s km – Eats squid, crabs, sardines
PDOand …
Switching of Alaskan &Wash/Oregon Catches
Related to PDO
Hypothesis: Spawning habitat First feeding
PD
O A
laska
n C
atch
OR
/WA
Catch
Mantua et al paper in reader
Estuaries!
WARM COOL
sardines = warm
anchovies = cool
Varved Sediments in Santa Barbara Basin
• Sediments form in annual varves
• Low O2 – little bioturbation – require C inputs
Fish Abundance from Varves
• Switching between anchovy & sardine
is seen – on 20 to 50 year time scales
• Policy implications are important
– Fishery collapses are not JUST due to
fishing
– Climate control of fish abundances
Fish & Climate
• The interaction of time scales are key
–Salmon its during spawning (precip or first feeding)
– Squid its egg survival & recruitment to adult stages
– Yellowtail its food availability (recruitment?)
– Sardine warm – anchovy cool (food web??)
• If time scales are similar, climate is important
• We know food webs structure changes due to
climate regime shifts
CalCoFIZooplankto
n
Hi Zoo’s = Low Temp
ENSO connection
All in pre-1977
CalCoFI Zooplankton
McGowan et al. [1998] in readings
Food Web
Changes
Zooplankton food web
Association of abundance among taxa
McGowan et al. [1998] in readings
Non ESNO
ESNO
SB Channel – Low Diatoms during 97/98 ENSO
Z(T=10oC)
Chlorophyll
Biogenic Silica - Diatoms
Food Webs & Climate
• Abundances of various components of marine
food web change due to climate
• Some evidence that food webs structure
changes too
– Dominant phytoplankton go from diatoms to mixed
– Zooplankton assemblages & associations change
too
• This alters food webs and the length &
intensity of food chains
Ch
avez
et
al. [
20
03
] p
ap
er
in r
ead
ing
s
Seabirds, Anchovy & Sardine off Peru
Chavez et al. [2003] paper in readings
Seabirds are dominated by a cormorant who lives off anchovy almost exclusively
Seabirds, Anchovy & Sardine off Peru
Sardine Synchrony Over Pacific
The Sardine Regime
The Anchovy Regime
Climate & Fish
• The interaction of time scales are key
– Salmon its during spawning (precip or 1st feeding)
– Squid its egg survival & recruitment to adult stages
– Yellowtail its food availability (recruitment?)
– Sardine warm – anchovy cool (food web??)
• If time scales are similar, climate is important
• We know food webs structure changes due to
climate regime shifts