Native predatory fish help control invasive species in Hawaiian fish ponds

He’eia fish pond

Jacks and barracudas in He’eia Fish pond eats Australian mullet, an invasive species that has been introduced Oahu Bodies of water in the 1950s. This finding suggests that these native predatory fish may represent a form of biological control of populations of the invasive mullet species. The study was Published in Aquaculture, fish and fisheries by researchers of university Hawaii at ManoaUniversity of California at Santa Barbara (UCSB) and Papae O He’eia.

Traditional fish ponds, called loco I, were once common in the coastal areas of the Hawaiian Islands and for centuries provided local communities with a sustainable and pragmatic solution to food security concerns. Fish pond management has typically focused on growing native mullets, moi and awa, which are herbivorous fish that thrived in fish pond environments. These coveted fish would be eaten by predatory fish such as mackerel and barracuda, which had to be removed from the fish pond on a regular basis. After that, invasive fish species were introduced Hawaii Water bodies, they got into fish ponds and changed the marine food webs of fish ponds.

Kaku or barracuda.

AH manoas Hawaii Institute of Marine Biology (HIM) Associate Research Professor and co-author of the study Eric Franklin said the importance of invasive mullet in the diet of predatory fish was unexpected.

“Our study showed that the introduction of the invasive Australian mullet altered the diet of native predators in the fishpond, which really advanced our understanding of the food web interactions in these systems,” Franklin said. “The mackerel and barracuda seemed to prefer feeding on the invasive mullet rather than native mullet and moi. This would help control the population of the invasive species that competes with the native fish for resources.”

Increase in locally produced food

loco I can be a tool to increase food security by producing seafood for local consumption. More than 80% of the in Hawaii is imported at a cost of nearly $3 billion annually. Economic analysis suggests that a small substitution of imported food would generate significant sales, revenue, government taxes and employment for the fish sector.

In 2019, more than 10 million tourists visited the Hawaiian Islands, creating an immense demand for food resources that far exceeded the needs of the 1.4 million residents. Previous studies have found that tourists Hawaii from the continental US are willing to pay more for locally sourced food while vacationing on the islands to help the state become a more sustainable tourism destination. A network of restored fish ponds could help fill this need.

“Restoring viable Hawaiian fish ponds represents a promising opportunity to increase local seafood production, but much remains to be learned about the ecology and dynamics of fish pond communities,” said the lead author and AH manoa Graduate Program in Marine Biology graduate student Anela Akiona. “A functioning fishpond would contribute to improved island food security, which can supplement catches from fisheries and other aquaculture operations.”

study details

Franklin said the research led to analyzes of predatory fish abundance and prey in the United States He’eia fish pond. The study used a tag recapture experiment, genetic barcoding, stable isotope analysis, and statistical methods to determine the numbers of jacks and barracuda in it He’eia Fish ponds and their nutritional composition.

The research team included Franklin, Akiona professors Rob Toonen out HIM and Brian Popp of the Department of Earth SciencesPostdoc Margaret Siple from UCSB and Keliʻi Kotubetey and Hi’ilei Kawelo by Paepae O He’eia. A group of volunteer fishermen from the community contributed to the tag recapture experiment. Volunteer interns at Laulima A “Ike The Pono program contributed to the collection and preparation of samples for stable isotope analysis. Akiona was supported by a Hauʻoli Mau Loa Foundation Graduate Scholarship at UH Manoa.


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