Ecological Effects and Coastal Zone Management Implications of Recently Discovered New England Populations of Two Fast-Growing Asian Seaweeds, Porphyra yezoensis Ueda and Porphyra katadae Miura
The goal of our proposed research is to assess the extent, impact and potential ecological threat(s) of Porphyra yezoensis and P. katadae in New England and to provide information needed for their effective management. The specific objectives of the project are:
1) To determine how long Porphyra yezoensis and P. katadae have been present in New England.
2) To determine the seasonality, geographic extent and expansion rates of these current populations.
3) To determine the ecological impact of current populations of Porphyra yezoensis and P. katadae.
4) To provide information and recommendations to coastal zone managers and regulatory agencies regarding the status and potential environmental threat(s) posed by the spread and/or further introductions of Asian Porphyra species.
Both Asian species are superficially similar to native Porphyra species. It is possible they have been collected previously in New England but not recognized. The first objective will be accomplished using a combination of morphological and molecular analysis of extensive herbarium collections of Porphyra that date back to the 1800s. The second and third objectives will be accomplished through seasonal field collections and quadrat sampling to compare community structure of impacted and non-impacted sites. The final objective will be met via reports and a Web site available to managers, regulators, scientists and other interested groups, through presentations at CZM and scientific meetings, and via publication in international journals.
The rocky intertidal is an area of intense competition for space and resources; it also represents critical habitat for a number of ecologically and economically important marine animals and plants. Invasive non-indigenous species can significantly impact intertidal ecology by displacing native species, sequestering nutrients, and utilizing common resources.
Very recently, populations of two Asian species of the red seaweed Porphyra have been discovered in New England. One of the species, P. katadae, has been confirmed at three sites on the bay side of Cape Cod and in the Cape Cod Canal. The second species, P. yezoensis, has been found at ten sites ranging from Maine to Connecticut. Using molecular data, the P. yezoensis populations in Long Island Sound have been identified as a commercial cultivar of P. yezoensis f. narawaensis. This is a very fast growing strain developed for the $1.2 billion Asian nori industry. It is grown extensively in Japan on nets in coastal bays, where it has also become established on natural substrata, causing the displacement and even extinction of some native species.
Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant
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