Using phylogenetic analysis to identify market substitution of

Atlantic salmon for Pacific salmon: an introductory

biology laboratory experiment

Erica ClineUniversity of Washington Tacoma

Environmental Science, Interdisciplinary Arts & Sciences

The Issue: Market

Substitution

• Intentional substitution of one species for another (more valuable or rare) species

• When and where it occurs:– Collapsed fisheries; e.g., cod– Illegal, unreported, or unregulated fishing– Difference in price

“The Cove”

You buy: Should be: Scientific name

But actually is: AKA:

Red snapper

Lutjanus campechanus

Sebastes spp. Oreochromis spp. Coryphaena hippurusIctalurus punctatus

Rockfish TilapiaMahi MahiChannel catfish

Cod Gadus morhua Theragra chalcogramma Alaska pollock

‘Wild’ salmon

Oncorhynchus spp.

Salmo salar Atlantic salmon (farmed)

Cases of substitution in the US

Based on Jacquet & Pauly 2008

Scientific name Original market name

Renamed

Squalus acanthias Spiny dogfish Rock salmon, Hass

Sebastes spp. Rockfish Pacific red snapper, Rock cod

Anoplopoma fimbria

Sablefish Black cod

Oncorhynchus keta

Chum salmon Silver brite salmon

Renaming—a related problem

Based on Jacquet & Pauly 2008

How common is it?

• FDA testing 1988-1997– 37% of fish mislabeled

• High school student project in NYC, 2008– 23% of seafood mislabeled

• Local fish processor sentenced to prison for substituting coho for king salmon

• NY Times and Consumer Reports studies: 40 to 75% of ‘wild’ salmon isn’t

Learning Objectives

1. Master the fundamental concepts of cell and molecular biology with application to a unifying theme and a socially relevant project.

2. Understand how molecular biology can be applied to a local environmental issue in our community.

• Students bring in salmon from local stores or restaurants

• Lab 1: DNA extraction and set up PCR reaction using mitochondrial cytochrome oxidase I (COI)

• Lab 2: Gel Electrophoresis and set up for sequencing

• Lab 3: Sequence analysis

How it works:

Equipment and Supplies

• Thermal cycler• Gel boxes, light box, and camera• Microcentrifuge• Pipettes, tips, tubes, gloves• Agarose, Taq polymerase, primers• DNA isolation kit, $2/sample• Sequencing: $175 per 96 samples• Sequence analysis: MEGA5

Example of Student Gel:

PCR Products

DNA + - Student samples ladder, ctr, ctr, 1 2 3 4

Results

coho

pink

king

Atlantic salmon

sockeye

chum

Atlantic salmon substituted for Pacific

Financial costs

Quantity For 14% substitution

Total US consumption of coho, sockeye, chinook salmon (2004)

83,000,000 lbs

Amount of this that was actually Atlantic salmon

=83,000,000 * substitution rate

11,620,000 lbs

Wholesale price if sold as Atlantic salmon

=$0.50/lb * mislabeled Atlantic salmon (lbs)

$5,810,000

Wholesale price if sold as coho, sockeye, or chinook (average price)

=$2.00 * mislabeled Atlantic salmon (lbs)

$23,240,000

Difference in price (cost to consumers)

Pacific salmon price – Atlantic salmon price

$17,430,000

• Other costs of salmon farming:– Environmental

problems• Nutrient runoff• Spread of disease• Escapes

– Human health• Up to 10x higher PCBs,

dioxins, PBDEs

Publications and future work

Lab manual and instructor manual will be on Curriculum for the Bioregion website and SERC educational materials site– www.evergreen.edu/washcenter/bioregion – http://serc.carleton.edu/bioregion/index.html.

• Cline, ET, Gogarten, J. Using phylogenetic analysis to detect market substitution of Atlantic salmon for Pacific salmon: an introductory biology laboratory experiment. Submitted to American Biology Teacher.