Shellharbour proudly partners with Macquarie University undertaking research of the beautiful Marlin species. 

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At the 2025 Blue Water Classic, a 140kg Blue Marlin was captured by team WaWa. The results of the stomach contents are below -

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Stomach Content Analysis

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Blue Marlin (Makaira nigricans)

Analysing Researcher: Tristan Guillemin

Capture Date: 28/3/25

Capture Location: Shellharbour

Weight of Fish: 140kg

Total Length: 276

Short Length: 238

Sex: Female

 

Main Result: A total of 3.69kg of stomach content were found in your fish.

 

For the weight of the fish, this gave a stomach fullness index of 2.729. This was a very high value and is the second highest we’ve recorded in over 60 blue marlin stomachs.

 

Of the 3.69kg of stomach content, we found the following (pictures below):

• 2 large skipjack tuna (Katsuwonus pelamis). Both of these tuna were 48cm fork length and weighed ~1.8kg. These are the most common prey we find in blue marlin, however, it is uncommon to see them this large in a blue marlin this size, especially two of them.

• 1 hirudinellid parasite. These are like a large leech which lives inside the stomachs of fish, they occur in about 50% of marlin stomachs. These results provide an insight into the feeding of marlin and help us identify the prey they depend on for survival and the areas they feed in. With further marlin samples, we will be able to get a big picture understanding of the species.

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