ISSN 1188-603X

No. 481 August 13, 2014 Victoria, B.C.
Dr. A. Ceska, P.O. Box 8546, Victoria, B.C. Canada V8W 3S2


From: Michael W. Hawkes, Dept of Botany, University of BC, Vancouver, BC

Accompanying plates:

The Japanese red alga, Mazzaella japonica (Mikami) Hommersand, is a source of carrageenan, which is commercially valuable (the GOOD), however, harvesting beach-cast material of this species is potentially damaging to intertidal habitat, fisheries, and removes important detritus from the food web (the BAD). In addition, this accidentally introduced species may also be invasive (the UGLY).

The genus Mazzaella currently contains 26 species (Guiry and Guiry, 2014), with 11 of these occurring in British Columbia (Saunders and Millar, 2014, who note: "...specimens of Mazzaella can be difficult to assign to accepted species due to their relatively simple morphologies confounded by intraspecific phenotypic plasticity." For a key to the species of Mazzaella from SE Alaska to Oregon see Gabrielson et al. (2012: 131-133). One of the best known species in our area is Mazzaella splendens, previously known as an Iridaea in reference to the bluish, oily sheen that the blade surface has when viewed at certain light angles. Mazzaella species vary in size, shape and vertical position on the shore. Some, like M. splendens are single blades, often lobed, tough and rubbery in texture and up to 40 cm or more in length. Mazzaella japonica is flattened and dichotomously to irregularly branched, but not rubbery in texture like M. splendens, nor as large. Like M. splendens, it grows from the low intertidal down into the upper subtidal. The natural distribution of M. japonica is Korea, Japan (I have seen and collected it at the type locality in Oshoro Bay, UBC A67273), and Russia. Its presence in British Columbia waters is thought to be due to accidental introduction, possibly via oyster aquaculture (Saunders, 2009).

During the zero foot low tide series in July, I was on the look-out for Mazzaella japonica. This species was first recognized in our marine flora about 10 years ago (although it may well have been here much longer than that) in the area from Deep Bay, at the south end of Baynes Sound, to Bowser on the east coast of Vancouver Island. It has subsequently been reported by Saunders and Millar (2014) at Comox, Hornby Island, and Nanaimo (the latter without specimen citation). This summer (12 July 2014), for the first time (after several years of looking), I found two attached plants (Figure 1) at the zero foot tide level on Newcastle Island off Nanaimo in the Strait of Georgia (herbarium specimens to be deposited in the UBC Phycological Herbarium in the Beaty Biodiversity Museum).

On the next day's low tide (13 July 2014), I went up to Deep Bay to see how widespread Mazzaella japonica has become in the area where it was first accidentally introduced. Much of the shoreline consists of cobble / boulder beach along with some gravel and sand. Such substrata are high disturbance habitat due to their frequent movement by wave action, especially during winter storms. Species diversity in such habitat is typically lower than on larger, solid substrata that experience less physical disturbance (Sousa, 1979).

Along the Deep Bay to Bowser shoreline, Mazzaella japonica forms a band from about the 2 ft tide level down into the subtidal. Mazzaella dominates the zone, with only a few other seaweeds mixed in with it, e.g. the Reds: Chondracanthus exasperatus, Neogastroclonium subarticulatum, Prionitis sternbergii, and Ceramium sp., and the Brown: Sargassum muticum (an infamous invasive species from Japan that was introduced with oyster spat many years ago). See Figs. 2-4. The exposed Mazzaella was suffering quite a bit of sun bleaching (low tide was at high noon and it was hot; about 32° C).

Kylee Pawluk, a Ph.D. student in the Dept. of Geography at the University of Victoria, is investigating the impacts of both Mazzaella japonica and Sargassum muticum in Baynes Sound. Recently she reported results from her field experiments, which demonstrated that attached Mazzaella japonica is having a negative impact on native seaweeds (Pawluk, 2014). So at least in her study area around Deep Bay to Bowser this alien seaweed appears to be outcompeting local species and may therefore be invasive. Given the abundance of this species in the Bowser area (both attached to the substratum as well as in the drift) it seems likely that it is here to stay and will displace local seaweeds if it expands its range further into the Strait of Georgia and possibly beyond.

This seaweed story gets more interesting, complex, and challenging from a resource management perspective. Like many red seaweeds, Mazzaella japonica contains cell wall chemicals known as carrageenans, complex sulphated polysaccharides that are used in a variety of food, pharmaceutical and industrial processes for their properties as emulsifying, gelling, and thickening agents. Carrageenan is a valuable product and there is commercial interest in it in British Columbia. In 2012, the BC Ministry of Agriculture issued 5 licences to harvest up to 1,000 metric tonnes / licence of beach-cast M. japonica along a 21 km length of shoreline between Deep Bay and Qualicum (in total, only 300 metric tonnes were actually taken). Harvesting was done with rakes and the seaweed packed into large sacks, which were then picked up on the beach by an all-terrain vehicle.

In 2013, as a result of feedback from concerned groups, the Ministry revised this pilot project by offering only 2 harvest licences, lowering the quota to a maximum of 300 metric tonnes / licence, and reducing the extent of the harvest area to a 5 km stretch of shoreline near Bowser. Again, harvest was limited to beach-cast Mazzaella and only hand-harvesting was permitted (BC Ministry of Agriculture, 2013).

At first glance this seaweed harvest seems like a good thing; a small, local industry harvesting beach-cast drift for its carrageenan content, as well as using some of the seaweed for cattle feed. For local media coverage see: Note: in the video clip Mazzaella japonica is referred to as 'Irish Moss', which is incorrect as this is the common name for the Atlantic red seaweed, Chondrus crispus, which looks superficially similar to Mazzaella japonica and also produces carrageenan. They also mistakenly report the seaweed as a local species rather than being non-indigenous.

Local groups have expressed concern that Mazzaella harvesting will negatively impact the beach and its biota especially spawning habitat of Pacific sand lance and surf smelt, both important food species for other organisms including commercial fishery species like salmon. Both physical damage done by harvesting, as well as ecosystem impacts through removing the decomposing seaweed from the food chain are a concern. Another concern, expressed by a Bowser homeowner in a letter to the Minister of Agriculture Norm Letnick and published in the Island Tides newspaper, is that waterfront property values will drop due to the industrial activity on the beach (Walker, 2014).

A recent study by Birtwell et al. (2013) and an E-Fauna BC Blog post by Carefoot (2013) summarize details of the food web and organisms potentially impacted. The scientific report by Birtwell et al. (2013) concludes with a call for further study before any more permits for harvesting are approved. Jurisdictional and legislative complexities of this issue have been thoroughly discussed by Brusse et al. (2013). Best to leave it be........or is sustainable harvesting of beach-cast Mazzaella japonica a viable option that could provide much-needed income to coastal communities? Can we have the GOOD, without some BAD? And what if it turns out to be UGLY? There are no easy solutions here.

Literature Cited

Birtwell, I.K., R.C. de Graaf, D.E. Hay, & G.R. Peterson. 2013.
Seaweed harvesting on the east coast of Vancouver Island, BC: Biological review. Unpublished report, 28 pp. Available from the Nile Creek Enhancement Society web page: L-REVIEW.pdf
Brusse, P. G. Jackson, & C. Sanborn. 2013.
Seaweed harvesting on Vancouver Island: A new industry that requires better regulation. Unpublished report by the Environmental Law Clinic, Univ. of Victoria, 38 pp. Available at:
BC Ministry of Agriculture 2013.
Mazzaella beach cast harvest licenses issued for 2013. Information Bull. #2013AGRI0046-001368.
Carefoot, T.C. 2013.
Ask an expert: seaweed harvesting in BC. E-Fauna BC.
Gabrielson, P.W., S.C. Lindstrom, & C.J. O'Kelly. 2012.
Keys to the seaweeds and seagrasses of Southeast Alaska, British Columbia, Washington, and Oregon. Phycological Contribution No. 8, [i]-iv, 1-192. Hillsborough, North Carolina: PhycoID.
Guiry, M.D. & Guiry, G.M. 2014.
AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. [searched on 04 August 2014]
Pawluk, K. 2014.
The direct impacts of an introduced seaweed Mazzaella japonica on benthic seaweed communities in Baynes Sound and possible interaction with the invasive seaweed Sargassum muticum. Abstract #630, 2014 Salish Sea Ecosystem Conference, April 30 - 2 May 2014, Seattle, WA.
Saunders, G.W. 2009.
Routine DNA barcoding of Canadian Gracilariales (Rhodophyta) reveals the invasive species Gracilaria vermiculophylla in British Columbia. Molecular Ecology Resources 9(Suppl. 1): 140-150.
Saunders, G.W. & K.R. Millar. 2014.
A DNA barcode survey of the red algal genus Mazzaella in British Columbia reveals overlooked diversity and new distributional records: descriptions of M. dewreedei sp. nov. and M. macrocarpa sp. nov. Botany 92: 223-231.
Sousa, W.P. 1979.
Disturbance in marine intertidal boulder fields: The non-equilibrium maintenance of species diversity. Ecology 60:1225-1239.
Walker, L. 2014.
Bowser Seaweed. Letter to the Editor, Island Tides 24 July - 6 Aug., Vol. 26: 5.

Figure Captions

For figures go to

Figure 1. Mazzaella japonica near Kanaka Bay, Newcastle I., Strait of Georgia. Up to 18 cm across. 12 July 2014.
Figure 2. Extensive band of Mazzaella japonica growing on cobble / boulder beach just south of Deep Bay, Vancouver I. 0' tide level, 13 July 2014. Mazzaella starts just below the green Ulva zone and continues down into the subtidal.
Figure 3. Mazzaella japonica on cobble, just south of Deep Bay, Vancouver I. 0' tide level. Up to 15 cm tall and 19 cm across. Sargassum muticum in the background. 13 July 2014. Figure 4. Reproductive Mazzaella japonica, on cobble just south of Deep Bay, Vancouver I. 0' tide level, 13 July 2014.


From: Dr. Mary Berbee, Curator of Fungi, UBC Herbarium, Vancouver, BC [originally posted on the Beaty Blog on April 8, 2014 -] For accompanying photos see

Have you ever wondered how the hundreds of black Beaty cabinets become filled with specimens? Beaty collectors include dedicated specialists from the community, who contribute dried specimens and detailed notes. Two outstanding contributors, Oluna Ceska, a mycologist, and Adolf Ceska, a plant ecologist, both from Vancouver Island, arrived at the Beaty loading dock on March 31, 2014 with 52 shoe boxes containing 3312 new specimens of dried fungi, collected from 2010 to 2013. As a team, the Ceskas have been collecting, preserving and photographing fungi from British Columbia for over many years. Since the end of November 2004, they have been conducting a long standing project to inventory the fungi fruiting on Observatory Hill, Victoria, BC, where Oluna has identified over 1200 species fruiting on less than 75 ha site.

This long-term project was initiated by Dr. Paul Feldman, and has been supported by the Herzberg Institute of Astrophysics, Garry Oak Ecosystems Restoration Team, and anonymous private donors. This project is unique in North America by its length and intensity of the survey. Cataloguing the Ceskas' most recent contribution to the UBC Beaty Museum was funded through a contract with the Canadian Wildlife Service, Environment Canada program, 'General Status of species in Canada'.

Over the past ten years, the Ceskas have been responsible for filling almost a fourth of those Beaty black cabinets that are dedicated to fungi, adding over 6400 specimens and bringing the number of fungal specimens in the Beaty museum to 26,771.

Fungi are important to BC ecosystems as mutually beneficial mycorrhizal partners of our forest trees, and as decomposers that help to recycle nutrients. In spite of their importance, many mushroom species remain to be described. The inventory of BC species is strikingly incomplete and fungi are underrepresented in the Beaty. The Ceska collections provide the specimens needed to expand knowledge of the richness of BC species and ultimately, to understand how these species function in BC forests.

For more information on the Oluna Ceska's Fungi of Observatory Hill project, visit:

The Ceska collections are establishing many new species records for BC and contain specimens of quite a few newly described, or yet undescribed species of fungi. See for example: Ammirati JF, Barlow TE, Seidl MT, Ceska O, Berbee M, Harrower E, Liimatainen K (2012) Cortinarius parkeri, a new species from the Pacific Northwest of North America. Botany 90:327-335. doi:10.1139/B2012-00

Send submissions to

BEN is archived at