Traceability and discrimination among differently farmed fish: a case study on Australian Murray cod

Area of Science:

• Aquaculture
• Food Science
• Analytical Chemistry

Background:

• Traceability of fish and seafood is crucial for consumers and industry.
• Distinguishing between wild-caught and farmed fish is established, but differentiating fish from various farms is challenging.
• Current methods lack specificity for identifying origins within aquaculture.

Purpose of the Study:

• To develop methods for discriminating between farmed Murray cod from different aquaculture systems and geographical locations.
• To evaluate the effectiveness of morphological, chemical, and isotopic analyses for intra-farm traceability.
• To identify key analytical markers for tracing farmed fish origins.

Main Methods:

• Analysis of farmed Murray cod from indoor recirculating, outdoor floating cage, and flow-through systems.
• Application of morphological, tissue proximate composition, fatty acid, and stable isotope analyses (delta(13)C, delta(15)N, delta(18)O).
• Statistical evaluation of analytical data to determine discriminatory power.

Main Results:

• Stable isotope ratios (delta(13)C, delta(15)N) correlated with specific commercial diets used in different farms.
• Delta(18)O values indicated distinct water sources associated with each farming system.
• Isotopic signatures provided clear discrimination among fish from different farms, outperforming other methods.

Conclusions:

• Stable isotope analysis is a highly effective tool for tracing the origin of farmed Murray cod.
• Isotopic markers can identify specific aquaculture systems, diets, and water sources.
• This method enhances traceability within aquaculture, complementing existing farmed vs. wild-caught distinctions.