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

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Project Type: 
Research
Project Number: 
R/CE-136
Inception Date: 
2006
Completion Date: 
2008
Theme Area: 
Coastal Ecosystem and Public Health

Participants:

Arthur Mathieson UNH - Jackson Estuarine Lab Principal Investigator
Christopher Neefus UNH - Department of Biological Sciences Co-Principal Investigator

Students Involved:

Troy Bray UNH - Department of Biological Sciences
Michelle Dare UNH - Department of Biological Sciences
Jeremy Nettleton UNH - Department of Biological Sciences
Abstract: 
Invasive non-indigenous seaweeds can significantly impact intertidal ecology by displacing native species, sequestering nutrients, and utilizing common resources. Populations of two Asian species of the red seaweed Porphyra have recently been discovered in New England. One of the species, P. katadae has been confirmed at five sites near Cape Cod. The second species, P. yezoensis has been found at 26 sites ranging from mid coastal Maine to Rye, New York. Using molecular data, seven P. yezoensis populations in Long Island Sound have been identified as a commercial cultivar of P. yezoensis f. narawaensis, which 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 extinction of some native species.
 
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 as follows:
 
• Determine how long Porphyra yezoensis and P. katadae have been present in New England.
 
• Determine the seasonality, geographic extent and expansion rates of the current populations.
 
• Determine the ecological impact of current populations of Porphyra yezoensis and P. katadae.
 
• 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.
 
As both Asian species are superficially similar to native Porphyra species (e.g. P. leucosticta and P. purpurea), it is possible that they have been previously collected in New England but not recognized. The first objective will be accomplished using a combination of morphological and molecular analyses of extensive herbarium collections of Porphyra that date back to the 1800s. The second objective will be accomplished through seasonal field collections. The third objective will be met through: 1) quadrat sampling to compare community structure of impacted and non-impacted sites; 2) similar quadrat comparisons of current community structure to historic data available at several sites; and 3) comparisons of physiological conditions of native species at impacted versus non-impacted sites. The final objective will be met via reports and a Website available to managers, regulators, scientists and other interested groups, through presentations at CZM and scientific meetings, and via publication in international journals.
Objectives: 

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.

Methodology: 

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.

Rationale: 

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.

Accomplishments: 
Multiple assessments of Northwest Atlantic seaweeds were employed, including historical and recent floristic studies, rapid assessment surveys, molecular enumerations of cryptic seaweed taxa, and morphological/ecological of evaluations. A total of four Asiatic taxa (i.e. Rhodophyta) were documented, including P. katadae A. Miura, P. suborbiculata Kjellman, P. yezoensis f. narawaensis A. Miura, and P. yezoensis f. yezoensis .

Publications

Available from the National Sea Grant Library (use NHU number to search) or NH Sea Grant

Journal Article

  • Neefus, C. and J. Brodie. Lectotypification of Porphyra elongata Kylin (Bangiales, Rhodophyta) and proposed synonymy of Porphyra rosengurttii Coll et Cox. Cryptogamie, Algologie 30(3):198-192, August 2009.
  • Bray, T., C. Neefus and A. Mathieson (2006). Morphological and molecular variability of "Porphyra purpurea" (Roth) C. Agardh (Rhodophyta, Bangiales) from the Northwest Atlantic. Nova Hedwigia 82(1-2):1-22, February 2006.
  • Brodie, J., I. Bartsch, C. Neefus, S. Orfanidis, T. Bray and A. Mathieson (2007). New insights into the cryptic diversity of the North Atlantic-Mediterranean "Porphyra leucosticta" complex: "P. olivii" sp. nov. and "P. rosengurttii" (Bangiales, Rhodophyta). European Journal of Phycology 42(1):3-28, 2007.
  • Mathieson, A., E. Hehre, C. Dawes and C. Neefus (2008). An historical comparison of seaweed populations from Casco Bay, Maine. Rhodora 110(941):1-102, Winter 2008.
  • Mathieson, A., J. Pederson and C. Dawes (2008). Rapid assessment surveys of fouling and introduced seaweeds in the Northwest Atlantic. Rhodora 110(944):406-478, December 2008.
  • Mathieson, A., J. Pederson, C. Neefus, C. Dawes and T. Bray (2008). Multiple assessments of introduced seaweeds in the Northwest Atlantic. ICES Journal of Marine Science 65(5):730-741, July 2008.
  • Neefus, C., A. Mathieson, T. Bray and C. Yarish (2008). The distribution, morphology, and ecology of three introduced Asiatic species of "Porphyra" (Bangiales, Rhodophyta) in the Northwestern Atlantic. Journal of Phycology 44(6):1399-1414, December 2008.
  • Teasdale, B., A. West, A. Klein and A. Mathieson (2009). Distribution and evolution of variable group-I introns in the small ribosomal subunit of North Atlantic "Porphyra" (Bangiales, Rhodophyta). European Journal of Phycology 44(2):171-182, 2009.
  • Mathieson, A., G. Moore and F. Short (2010). A floristic comparison of seaweeds from James Bay and three contiguous Northeastern Canadian Arctic sites. Rhodora 112(952):396-434, October 2010.

Thesis/Dissertation

  • Bray, T. (2006). A molecular and morphological investigation of the red seaweed genus "Porphyra" (Bangiales, Rhodophyta) in the Northwest Atlantic. Doctoral dissertation, University of New Hampshire.
  • Nettleton, J. (2008). Ecology, distribution, quantification and impact of introduced, Asian "Porphyra yezoensis" f. "yezoensis" Ueda and "Porphyra yezoensis" f. "narawaensis" A. Miura in the northwestern Atlantic. Master's Thesis, University of New Hampshire.