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Consistent harvesting strategy in salmon aquaculture Dubreuil, Michel
Abstract
The goal of this study was to design a consistent harvest strategy using various types of salmon smolts differentiated by species, weight and timing of introduction into seawater. Consistent harvesting is a production strategy leading to the continuous harvest of fresh salmon at a predictable size 52 weeks of the year. The economic and production characteristics of six chinook salmon (Oncorhynchus tschawytscha) and six Atlantic salmon (Salmo salar) cohorts were first analyzed to establish the economic and production factors leading to their respective optimal harvest time and to compare the performance of each cohort. The study was developed with reference to the British Columbia salmon farming industry. To achieve these objectives, a discrete and deterministic bioeconomic model was developed following the theoretical framework proposed by Bjorndal (1988, 1990). A series of sub-models were incorporated to simulate three major components of the biological system. First, fish growth was simulated using a modified Iwama-Tautz growth model to which was added a dampening factor to embody a size/growth relationship. Second, feed requirements was computed using a bioenergetic feeding model based on a formulation empirically derived by Cho (1992) and the work published by Maroni et al (1994) on differential feed conversion efficiencies. Finally, two mortality rate scenarios were specified on the basis of the underlying causes of mortality and the effect of sexual maturation on fish quality and survival. In scenario 1, a fixed mortality rate was relaxed by the convergence of two conditions beyond which the mortality rate began to increase. These conditions were specified as a lower fish weight threshold and a spring to fall timeframe during the year. In scenario 2, the mortality rate was assumed fixed through the production cycle. The results showed that most fish cohort had a comparative advantage in terms of maximizing returns over a specific market window during the year. The major factors determining the comparative advantage of each cohort were life expectancy and growth performance in relation to water temperature. As a result, the optimal harvest timeframe for a cohort selected within a production portfolio could differ from its own optimal harvest time as a single production unit.
Item Metadata
Title |
Consistent harvesting strategy in salmon aquaculture
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1998
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Description |
The goal of this study was to design a consistent harvest strategy using various types of salmon smolts
differentiated by species, weight and timing of introduction into seawater. Consistent harvesting is a
production strategy leading to the continuous harvest of fresh salmon at a predictable size 52 weeks of the
year. The economic and production characteristics of six chinook salmon (Oncorhynchus tschawytscha)
and six Atlantic salmon (Salmo salar) cohorts were first analyzed to establish the economic and production
factors leading to their respective optimal harvest time and to compare the performance of each cohort.
The study was developed with reference to the British Columbia salmon farming industry.
To achieve these objectives, a discrete and deterministic bioeconomic model was developed following the
theoretical framework proposed by Bjorndal (1988, 1990). A series of sub-models were incorporated to
simulate three major components of the biological system. First, fish growth was simulated using a
modified Iwama-Tautz growth model to which was added a dampening factor to embody a size/growth
relationship. Second, feed requirements was computed using a bioenergetic feeding model based on a
formulation empirically derived by Cho (1992) and the work published by Maroni et al (1994) on
differential feed conversion efficiencies. Finally, two mortality rate scenarios were specified on the basis
of the underlying causes of mortality and the effect of sexual maturation on fish quality and survival. In
scenario 1, a fixed mortality rate was relaxed by the convergence of two conditions beyond which the
mortality rate began to increase. These conditions were specified as a lower fish weight threshold and a
spring to fall timeframe during the year. In scenario 2, the mortality rate was assumed fixed through the
production cycle.
The results showed that most fish cohort had a comparative advantage in terms of maximizing returns over
a specific market window during the year. The major factors determining the comparative advantage of
each cohort were life expectancy and growth performance in relation to water temperature. As a result, the
optimal harvest timeframe for a cohort selected within a production portfolio could differ from its own
optimal harvest time as a single production unit.
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Extent |
5738111 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-05-04
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0088398
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1998-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.