Title: Past Records of Salmon Abundance by Francis Choi
1Past Records of Salmon Abundanceby Francis Choi
2Outline
- The importance of salmon abundance information
- What are salmons?
- Methods to measure the abundance
- Causes for abundance variation
- Study 1 climate and salmon abundance
- Study 2 biocomplexity and salmon sustainability
- Problems in past salmon abundance data
- Present day population dynamics of the salmon
- Future direction of salmon sustainability
3Why is Salmon abundance important?
- It is all about fish stock sustainability
- With salmon abundance history
- Management and stock prediction can be made
- Maximum stock harvest can be estimated
4Why do we want to sustain the salmon stock?
- Salmon is an important part of the North American
Pacific Coast. - Pacific Canada culture
- - part of the heritage of many First Nations of
BC - - ceremonial use
- - everyday resource food, tools, medicine
- - commercial trading
-
5Why do we want to sustain the salmon stock?
- Salmon is a backbone resource for Pacific coastal
economy - - commercial or recreational fishing
- - fish dependent businesses
- - Marina operations
- - Fish processing
- industries
- - Transportation/distributor
- - Boat building and repair
- business
- - retail fish sales
6What is a salmon?
- They are anadromous fish
- Two types
- Pacific salmon Atlantic salmon
- - terminal spawners - repeated spawners
7- Types of salmon found on the Pacific coast
-
- Chinnok
-
- Chum
- Coho
- Sockeye
- Pink
8Methods to measure salmon abundance
- Past accumulated data of the CPUE of the salmon.
- CPUE Catch per unit effort
- N15 isotope-indicators
- - Algal bio-indicators
- Past DNA check
- Visual juvenile monitoring
9Abundance of salmon can be affected by
- Combination of
- Human disturbance
- - harvesting
- - pollution
- - urbanization
- Biotic factor
- - predation
- - competition
- Abiotic factors
- - climate change
-
10- Climate change can affect
- - flow rate of streams
- change in spawn location
- migration time
- - Life history time
- spawning time
- hatching time
- - favorable spawning location
- - abundance of food resources
- biomass of salmon
11- Advantages for studying the population dynamics
of Pacific salmon -
- - Have more accurate methods for
measuring abundance - - able to use algal bio-indicator and N15
isotopes -
- - Pacific Ocean is less disturbed than
Atlantic Ocean - - human disturbance can be eliminated from
factors affecting salmon abundance
12Study 1 Fisheries productivity in the northern
Pacific Ocean over the past 2,200 yearsFinney
B.P., Gregory-Eaves I., Douglas M.S.V. Smol
J.P. (2002) Nature, 416, 729-733
- The study creates the abundance of Pacific
sockeye for the past 2,200 years - Purpose determine that climate variability is
related to the population dynamics of the
Pacific salmon - Methods used N15 isotopes, algal bio-indicators
- collected core samples from spawning sites
- - used N15 (SDN) and the abundances of diatom
remains as indexes for measuring the abundance
of salmon at a certain time - SDN salmon derived nutrients
13Area of observation
Kodiak Island, Alaska 3 lakes Karluk Lake
(main lake), Afognak Lake, Frazer Lake
(controlled)
14Figure 1 N15 isotope () and diatom abundance
() through 2,200 years in Karluk Lake
Oligotrophic diatom domination
Mesotrophic diatom domination
15- Results from Figure 1
- - 100BC Decline in N15 isotopes (abundance of
salmon) - Decline in mesotrophic diatom taxa
- Increase in oligotrophic diatom taxa
(Cyclotella Comensis, Cyclotella
ocellata) - (oligotrophic taxa dominant)
- (suggest ? colder climate)
-
- - 250 AD Increase in N15 isotopes
- Increase in mesotrophic diatom taxa
- Decrease in oligotrophic diatom taxa
-
- - 1200 -1900 High percentage of N15
- (suggest high abundance in salmon)
- Mesotrophic diatom taxa dominants
- (suggest ? warmer climate)
16Figure 2 Sockeye salmon from Kodiak Island
compare to other fish species along the pacific
coast through 2,200 years.
Data collected from the coast of California
Data from the coast of southern British Columbia
17- Results from Figure 2
- - Karluk Lake Sockeye salmon show a negative
correlation with the other fish species to the
south. - - Salmon shows weak abundance before 1200 AD,
while the other fish species to the south show
strong abundance - - After 1200 AD, their characteristic reversed
- - This study suggest there might be a shift in
ocean-atmospheric circulation that moved north
to favor the salmon population of Karluk Lake. -
18Study also observed that cultural change can also
affect salmon abundance
- At each transition between archaeological
phases, there is a dramatic change in salmon
abundance. - Early to Late Kachernak
- It is known that there were huge cultural
change at this period, this study suggests this
cultural change could have involve the
population of salmon. - Kachernak to Koniag
- Evidence of a shift towards greater abundance
of fishing tools -
19Study 2 Biocomplexity and fisheries
sustainabilityHilborn, R., Quinn, T. P.,
Schindler, D. E., Rogers, D. E. (2003)
Proceedings of the National Academy of Sciences
of the United States of America, 100, 6564-6568.
- Purpose provide evidence that biocomplexity also
affects the stability and sustainability of the
Pacific salmon stock -
- Species used Pacific Sockeye in Bristol Bay,
Alaska
20- Sites of study Three fishing sites at Bristol
Bay - Nushagak, Naknek-Kvichak, Egegik
21Table of biocomplexity of sockeye salmon
determined in Bristol Bay
Using two case studies to present how climate
variation affect the biocomplexity of salmon,
thus changing the salmon abundance through time
22Case 1 climate variation and flow rate -
determine how Pacific Decadel Oscillation (PDO)
correlated with salmon abundance
- Method Comparing stream flow (index) to PDO
through the past decade - Result high flow is positively correlated with
PDO anomaly - High flow high sockeye productivity
- - increase access to nursery for larger fish
- - reduced migration time to the ocean
- - reduced vulnerability for juveniles to
encounter freshwater predators
23Case 2 Climate variation and Pattern of
productivity - to determine changes in abundance
within different sites
Method Using past catch data from the three
fishing site to reconstruct past salmon abundance
from 1890-2000
Results - Before 1977, the sockeye production
was ranked as followed Naknek- Kviehak,
Nushagak, Egegik - After the regime shift of PDO
in 1977, Egegik increased dramatically
- Nushagak remained small.
- In 1990, Egegik stock diminished, Naknek-kviehak
crashed but Nushagak increased to the present
most important fishery in Bristol Bay - Concludes At different times, different
biocomplexity variations will favor one site over
the others
24Recap of Study 1 and 2
- Study 1
- - using N15 in core sample to determine climate
change is correlated with salmon abundance in
the past - - It presented a long term population dynamics
of salmon at one site - Study 2
- - Using past flow rate and PDO change to suggest
that climate change is correlated with salmon
abundance - - Using catch to determine that different sites
will have different opportunities to become
productive at certain biocomplexity that favors
the site - - This study presented a short term population
dynamics of salmon at multiple sites. - Both studies stress that climate variation
influences the past dynamics of salmon, therefore
understanding the climate and the population
dynamics link can lead to a better sustainability
for the salmon stock.
25Problems with the population dynamics for the two
studies
- The indexes are not accurate
- - CPUE
- - CPUE catch / effort (where catch harvest
ratebiomass) - - Data collected from fishermen
- - N15 isotopes
- - Climate change, created variations in
spawning locations along the river - - Therefore, hard to estimate a consistent
nursery site -
26Present day population dynamics of salmon
- Human interactions has the greatest affect on the
present age abundance of salmon. - Abundance of stock is now depended on the
management of the stock by each country - - Alaska (Record high abundance of salmon)
- - Scandinavian (Growing abundance)
- - British Columbia (declining population)
- - Ireland (declining population)
27Future directions for sustaining salmon stock
- Well planned and strict management policies
implemented for ALL salmon nurseries. - Fixed escapement policy or fixed harvest rate
policy - Use more recent and more accurate methods to
collect the population dynamics of salmon - Visual juvenile counting
- Mark-Recapture method, most recent DNA tagging
28Reference
- Key reference
- Finney B.P., Gregory-Eaves I., Douglas M.S.V.
Smol J.P. (2002) Fisheries productivity in the
northeastern Pacific Ocean over the past 2,200
years. Nature, 416, 729-733. - Hilborn, R., Quinn, T. P., Schindler, D. E.,
Rogers, D. E. (2003) Biocomplexity and fisheries
sustainability. Proceedings of the National
Academy of Sciences of the United States of
America, 100, 6564-6568. - Other reference
- Gregory-Eaves I., Finney B., Douglas M.S.V., Smol
J.P. (2004) Inferring sockeye salmon
(Oncorhynchus nerka) population dynamics and
water quality changes in a stained nursery lake
over the past 500 years. Canadian Journal of
Fisheries Aquatic Sciences, 61(7), 235-1246. - Schindler D., Leavitt P., Johnson S., Brock C.
(2006) A 500-year context for the recent surge in
sockeye salmon (Oncorhynchus nerka) abundance in
the Alagnak River, Alaska. Canadian Journal of
Fisheries Aquatic Sciences, 63 (7), 1439-1444. - Boylan P., Adams C.E. (2006) The influence of
broad scale climatic phenomena on long term
trends in Atlantic salmon population size an
example from the River Foyle, Ireland. Journal of
Fish Biology, 68 (1), 276-283. - Gregory-Eaves I., Smol J., Douglas M.S.V., Finney
B.P. (2003) Diatoms and sockeye salmon
(Oncorhynchus nerka) population dynamics
Reconstruction of salmon-derived nutrients over
the past 2,200 years in two lakes from Kodiak
Island, Alaska. Journal of Paleolimnolgy, 30,
35-53 - Camilla F., Yang D.Y., Hayden B. (2005) Ancient
DNA investigation of prehistoric salmon resource
utilization at Keatly Creek, British Columbia,
Canada. Journal of Archaeological Science, 32(9),
1378-1389