If you’ve ever collected ‘opihi, and wondered why they’re always clinging to shore rocks that take a pounding from the waves, here’s an interesting factoid: these molluscs have poorly formed gills and require a mix of air and highly oxygenated, surging seawater to breathe. In fact, prolonged submersion in seawater could result in suffocation or drowning.
In a new study funded by the UH Undergraduate Research Opportunities Program, PhD candidate Anthony Mau and MS student Angelica Valdez of the Dept. of Molecular Biosciences and Bioengineering found that crashing waves and temperature influence the seasonal growth patterns and reproduction of the yellowfoot limpet, or ʻopihi ʻālinalina, an intertidal species endemic to the Hawaiian Islands. Their conclusions may lead to improved techniques in farming ʻopihi.
This paper reveals the first age estimates and growth-curve for ‘opihi, which “continues in a similar trajectory through 2 years of age, a time-point that is well beyond their first reproductive term at 8-9 months old,” says Anthony, the study’s lead author. “Based on our previously published research, we know that female fecundity, or a measure of reproductive potential, is significantly greater with increasing shell length. If we connect the dots, we should really be focusing on these older ‘opihi (40-50 mm long) as broodstock for hatchery production of seed (juvenile ‘opihi).”
He adds, “As we begin to explore and understand the role of temperature on growth and reproduction, we will be able to improve our techniques to farm 'opihi. This work also provides important information to develop sustainable fishing practices and management strategies of our intertidal fishery. We are collaborating with other UH research arms and local, non-profit groups to monitor 'opihi populations and develop effective strategies to conserve the species for future generations.”
The study, “ʻOpihi growth patterns influenced by Hawaiian intertidal environment,” was done in collaboration with the UH School of Ocean and Earth Science and Technology (SOEST) and appears in the latest Nature. Read more in UH News.
Photo: Anthony Mau (center) and study collaborators during a 2017 intertidal research and opihi survey in Papahānaumokuākea Marine National Monument.