HILO — Months after communties on Kauai gathered to get invasive tilapia out of the nearshore waters on the North Shore, residents in Hilo are seeing large schools of tilapia in the Waiola River system.
They’re not the same type of tilapia — these are Nile tilapia, the ones on Kauai were Black Chin tilapia — but the state Department of Land and Natural Resources Division of Aquatic Resources is taking the same approach it did on Kauai, encouraging residents to eat them, for now.
The tilapia invasion was announced in a Friday news release from DLNR, which said: “There are no restrictions or bag limits on tilapia, and for now biologists say catch and eat as many as you want.”
The release also hinted at a potential open fishing tournament on Hawaii Island to control the expanding population of the invasive fish.
According to DLNR, the Nile tilapia were reclassified by the state Board of Agriculture two years ago as a restricted species only for research. That permits importation for aquaculture faciltities to farm-raise the tilapia.
The reasons behind the current increase in the Nile tilapia invasion in Hilo are not known, but biologists caution that while aquaculture farming facilities are “closed systems,” all it takes is one lapse in biosecurity measures to start a quick invasion population of these fish.
The department says while there’s no evidence that a recent invasion of the tilapia in freshwater streams has anything to do with commercial farming operations, it confirms fears DLNR-DAR leadership and biologists expressed when board members were debating whether to allow the state Deptartment of Agriculture to revise its rules to permit aquaculture importation of Nile tilapia.
“Unfortunately, Hawaii has a long history of bringing in species, thinking that they’ll provide some commercial or ecosystem benefit, to discover later that these same species out-compete native species,” said Brian Neilson, DAR Administrator, in Friday’s news release.
“We are now seeing stark evidence of this. While Nile tilapia were present in the Hilo waterways before aquaculture operations began, reports of Nile tilapia or hybrids are on the rise, indicating that their population may be increasing, and their range may be expanding. That’s the real downside of bringing non-native species into the state for any reason,” Neilson said.
Local fisherman, as with a recent invasion of black chin tilapia along Kauai’s Napali Coast, were among the first to see and report increasing numbers of Nile tilapia in the Wailoa River and its associated waterways.
On Kauai, locals noticed large amounts of tilapia in the nearshore waters in the Napali Coast State Wilderness Park in July, particularily near Nu‘alolo. Biologists theorize those fish washed into the ocean from one of Kauai’s Westside ditch systems after heavy rains.
In early September, DLNR partnered with Kauai fishermen to remove the majority of the fish from the area.
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Jessica Else, environment reporter, can be reached at 245-0452 or jelse@thegardenisland.com.
