Invasive fish ta`ape maintains diversity by fast invasion

It seemed to make so much sense back then—if native species aren't doing well, just bring in stronger competitors rather than figuring out why the locals aren't thriving.

(Image: The introduced snapper, Lutjanus kasmira, commonly known as taʻape. Credit: Keoki Stender)

It happened in forestry, bringing in alien trees to reforest the Islands, rather than figuring out why the native forests were ravaged.

And it happened in fisheries, when the Hawai`i Territorial Division of Fish and Game determined, around the time of statehood, to supplement the islands' existing nearshore marine species with three alien reef fishes, Lutjanus fulvus (blacktail snapper or to‘au), Cephalopholis argus (blue-spotted grouper or roi) and Lutjanus kasmira (bluestriped snapper or ta‘ape).

What's been the result? A couple of them have done so well that organizations sponsor targeted fishing tournaments to try to reduce their impact on the reefs and the native species.

A group of scientists from the Hawai`i Institute of Marine Biology has studied the genetics of the three species to learn what happened to them as they settled in to their new Hawaiian home. The researchers are Michelle Gaither, Robert Toonen, and Brian Bowen.

They were released on O`ahu and Hawai`i Islands, but quickly spread to all the Main Hawaiian Islands, and the ta`ape traveled more than 1,000 miles right up the Northwestern Hawaiian Islands chain to Midway Atoll. Roi thus far has made it to French Frigate Shoals. Only to`au remains in the main islands.

The researchers found that the fast-spreading ta`ape maintained its genetic diversity—a diversity similar to that found in the ta`ape of its source islands in Fresh Polynesia. But the slower-spreading species, particularly the to`au, lost much of their genetic diversity.

It suggests that fast growth itself may play a role in protecting diversity of invasive species, they write.

“We now have a better idea of why some species are more successful invaders than others. The faster a species becomes established in its new environment, the faster it finds food and begins to reproduce, the more likely it is to maintain the genetic diversity that is so important to its long term success as an alien species,” said Gaither, in a press release.

For more information the Hawai`i Institute of Marine Biology work in the Northwestern Hawaiian Islands, see www.hawaii.edu/himb/nwhi/. The abstract from their paper in is here: www.ncbi.nlm.nih.gov/pubmed/22874747. The publication is Proc Biol Sci. 2012 Aug 8.

© Jan TenBruggencate 2012

Two major new climate research efforts at UHawai`i

Hawai’i is increasingly active in the science of the Pacific, with island-based researchers contributing to global research efforts.

Two new federally funded research efforts have just landed in Hawai`i.

Recently, the University of Hawai`i announced that NOAA has committed up to $95 million for a five-year program to study coastal and marine resources in connection with changes to the environment.

It will run through UH’s Joint Institute for Marine and Atmospheric Research (JIMAR), to be headed by oceanographer Mark Merrifield. It will be one of 18 such cooperative institutes across the country.

Among the specific projects: “assessment of local fish stocks, monitoring and ecosystem-based management policies for coral reef ecosystems including the Northwestern Hawaiian Islands, development of remediation strategies for endangered Monk Seal populations, monitoring of global sea level rise and local sea level impacts, modeling of volcanic smoke and haze (VOG), improved forecasts of hurricane intensities, projections of ENSO variability and impacts on Pacific island states, and provision of water level observations for tsunami warning.”

Meanwhile, the Interior Department announced that it will fund the development at UH of the Pacific Islands Climate Science Center, one ofseveral such climate centers across the U.S. This one will be a joint project of University of Hawai'i at Mānoa, the University of Hawai'i at Hilo, and the University of Guam.

Again, its goal will be to help our nation cope with climate change and “other landscape-style stressors impacting the nation’s natural and cultural resources.”

“The new climate center will serve as a resource for federal agencies and other stakeholders in providing the necessary science input into policy decisions. It will also support research and graduate student training on a variety of environmental concerns with a primary scientific focus on understanding the effects of climate change and variability on island ecosystems,” said Kevin Hamilton, the director of the UH’s International Pacific Research Center, who iwill head the new Pacific Islands Climate Center.

The university expects initial funding to be in the neighborhood of $3 million over 5 years, and anticipates the Department of Interior will station several federal scientists in Hawai`i to work with the project.

© Jan TenBruggencate 2011