New Zealand Journal of Botany, 2013 Vol. 51, No. 1, 7174, http://dx.doi.org/10.1080/0028825X.2012.728137

SHORT COMMUNICATION A new record of percursa (, ) on the North Island, New Zealand SJ Pratta, CJ Lundquistb*, W Nelsonc and CEC Gemmilla aDepartment of Biological Sciences, University of Waikato, Hamilton, New Zealand; bNational Institute of Water and Atmospheric Research Ltd (NIWA), Hamilton, New Zealand; cNational Institute of Water and Atmosphere Research Ltd (NIWA), Wellington, New Zealand (Received 2 May 2012; accepted 30 August 2012)

The filamentous green alga (Ulvaceae, Ulvales) was recorded for the first time on the North Island of New Zealand at O¯ mokoroa Estuary, Tauranga Harbour. This species is previously known within New Zealand from only two records, both from the South Island. In Tauranga Harbour, this species was restricted to anoxic estuarine sediments where mangrove forests had been mulched, and mulchate left in situ. Percursaria percursa was found intertwined with Ulva spp. and Rhizoclonium spp. Surveys of other North and South Island estuaries suggest that this alga, although occurring as part of nuisance green algal blooms in Tauranga Harbour, has only colonized human-impacted locations, and has not yet been observed in ‘natural’ estuarine ecosystems in New Zealand. As this species was found intertwined with other mat-forming filamentous green , it can easily be misidentified in the field, leading to both over- and under-reportingof species occurrence. Keywords: Percursaria percursa; Ulvaceae; Tauranga Harbour; mangrove; macroalgal blooms; New Zealand

Introduction uncommon or cryptic indigenous species or an Here we report a new record of the macroal- introduced non-indigenous species. gal species Percursaria percursa (C. Agardh) The Percursaria Bory (Ulvaceae) is Rosenv. (Ulvaceae) at O¯ mokoroa Estuary, monotypic and is comprised currently of the Tauranga Harbour, North Island, New Zeal- single recognized species P. percursa (Guiry & and. Percursaria percursa has previously been Guiry 2012). The species is widely distributed recorded only twice in New Zealand waters globally with extensive representation through- Downloaded by [University of Waikato] at 15:01 11 April 2013 from South Island localities. Laing(1927, 1932) out the coastal margins of the Pacific and recorded it from Kaikorai, Dunedin, but this Atlantic oceans (Garbary et al. 1985; South record was questioned by Naylor (1954) as no 1984; Wynne 1986), usually in sheltered bays authenticated voucher was found in Laing’s and inlets in the upper intertidal region herbarium. Percursaria percursa has also been (Londry et al. 2005). Percursaria percursa is a found from highly modified hypersaline la- filamentous green alga that forms dense, bright goons and channels adjacent to Lake Grass- green clumped mats on the substrate. While this mere, Marlborough (Adams 1994). Based on alga is virtually indistinguishable in the field the few records available for this species, it is from other filamentous green algae such as currently difficult to determine whether it is an Rhizoclonium spp., it is readily identified in the

*Correspondingauthor. Email: [email protected]

# 2013 The Royal Society of New Zealand 72 SJ Pratt et al.

laboratory with the aid of a compound We observed P. percursa only on the highly microscope. anoxic (oxic layer generally B5 mm deep) The first documented record of P. percursa mangrove mulchate along with Ulvaceae and on the North Island of New Zealand was at other filamentous green algae. These multi- O¯ mokoroa Estuary, Tauranga Harbour, in species macroalgal blooms (C. J. Lundquist, April 2010 (Table 1). Large patches (1 ha) NIWA, pers. obs.), including P. percursa, of filamentous green algae were also observed Rhizoclonium spp. and Ulva spp., were found colonizingdisturbed substrates where man- in highest abundance in spring months. Large groves were removed in four other estuaries in patches of filamentous green algae were re- Tauranga Harbour (Waikareao, Waikaraka, corded in O¯ mokoroa in 2010, and sub-samples Te Puna and Matua estuaries); however, confirmed the presence of P. percursa, and did P. percursa has not yet been documented at not confirm presence of other filamentous these sites. All putative records have been green algae such as Rhizoclonium spp. Detailed associated with localized disturbances due to samplingin 2012 found macroalgalblooms to deposition of post-removal mulched mangrove be comprised of multispecies aggregations at all (Avicennia marina subsp. australasica (Walp.) locations, suggesting that the large patches of J.Everett). Large seasonal blooms of filamen- filamentous green algae observed in 2010 were tous green algae, similar in timing to blooms of likely to also be multispecies aggregations. other Ulvaceae such as (Ulva sp.) and other filamentous green algae such as Morphology Rhizoclonium spp. (Cladophoraceae), have We observed mats, both fresh and rehydrated, formed at most mangrove clearing sites; these under400 magnification on a compound blooms are probably fuelled by high nutrient microscope; this was the minimum magnifica- availability at these disturbed sites, although in tion at which we could make reliable determi- situ nutrient release associated with mangrove nations. The thalli of P. percursa are generally mulchate has not been quantified. unbranched, biseriate filaments (Londry et al. 2005; Guiry & Guiry 2012) (Fig. 1). The filaments are also typically contorted in Distribution and habitat appearance. The filament cells are square to Percursaria percursa presence in the North slightly elongate, typically 1025 mm wide Island of New Zealand was confirmed from 1040 mm in length (Guiry & Guiry 2012). three collections at O¯ mokoroa Estuary, Taur- The two rows of cells are more or less anga Harbour, made in 2010 and 2012. The symmetrical, with each cell containinga single

Downloaded by [University of Waikato] at 15:01 11 April 2013 locality is described as an upper intertidal parietal chloroplast (Londry et al. 2005). It is mudflat of the greater Tauranga Harbour not uncommon for filaments to become uni- (Table 1). The site is inundated with harbour seriate for short lengths (Bliding 1963; Londry water twice daily for B6 h per tidal cycle. et al. 2005). The life history of this species

Table 1 Collection sites of Percursaria percursa at O¯ mokoroa Estuary, Tauranga Harbour, Bay of Plenty, North Island, New Zealand.

Sample ID Date collected GPS coordinates Det. Voucher

ASK204 10 November 2010 37839.006?S 176802.235?E W. Nelson WELT A032066 ASK205 10 November 2010 37839.006?S 176802.235?E W. Nelson WELT A032067 SJP15 23 January 2012 37839.056?S 176802.310?E S. Pratt WAIK 22539 A new record of Percursaria percursa on the North Island, New Zealand 73

distribution records which are all associated with sites that have been modified by human activity, however, it is possible that this species is a cryptic and uncommon indigenous species that has evaded detection until recently. The origin(s) of the population of P. percursa at O¯ mokoroa is unknown at this time and monitoringshould continue to esti- mate the extent and frequency of occurrence of this species. Small-scale samplingof macroalgal blooms associated with mangrove removals at selected sites in Auckland and Whangamata¯ harbours, as well as other sites within Tauranga Harbour (Waikaraka, Waikareao, Te Puna and Welcome Bay estuaries) has not found any P. percursa present. Extensive field samplingin Auckland estuaries in unmodified habitats did not detect this species, and it was not recorded in a national survey of soft sediment habitats in Wha¯nga¯rei, Otago and Kaipara harbours, though Ulva spp. and Rhizoclonium spp. were Figure 1 Low-light photomicrograph of a biseriate recorded in all harbours (Neill et al. 2012). filament of Percursaria percursa (not stained). Sam- Elsewhere P. percursa is generally found within ple SJP15, O¯ mokoroa Estuary, Tauranga Harbour, upper tide-pools and salt marshes (Londry Bay of Plenty, North Island, New Zealand. et al. 2005). We observed P. percursa only in association with highly anoxic substrate, gen- alternates between isomorphic gametophytes erally as part of multispecies blooms with and sporophytes (Bliding1963). The species is Ulvaceae and other filamentous green algae. capable of both asexual and sexual reproduc- This environmental condition is associated tion, producingquadriflagellatedzoospores with the human modification of the harbour and biflagellated anisogametes, respectively. through consented mangrove removal by Percursaria percursa can be easily distin- mulching. In Tauranga Harbour, mangrove guished under 40 magnification from other management has occurred as a response to filamentous green algae and Ulvaceae with increasingmangrovedistributions, which are which it often co-occurs, due to its biseriate

Downloaded by [University of Waikato] at 15:01 11 April 2013 linked to changes in land-based inputs to the filaments; Rhizoclonium has uniseriate fila- harbour (Green et al. 2003). Mangroves in ments with square to rectangular-shaped cells Tauranga Harbour have increased substan- and Ulva spp. have two layers of cells (Guiry & tially from B20 ha aerial coverage in 1943 to Guiry 2012). c. 550 ha in 2001 (Park 2004). Percursaria percursa is not recognized as a nuisance species in the worldwide literature, in Discussion comparison with Ulva spp. that form extensive This record of P. percursa from the North blooms in European and North American Island of New Zealand adds to the current estuaries, as well as extensive blooms in Taur- records of the distribution of this species both in anga Harbour (de Winton et al. 1998). Because New Zealand and internationally. We refer to macroalgal blooms often require management the species as non-indigenous given its restricted action to mitigate smothering of benthic 74 SJ Pratt et al.

communities and anoxic conditions, it is likely de Winton MD, Hawes I, Clayton JS, Champion that the presence of macroalgal blooms on PD, Smith RK 1998. Sea lettuce dynamics and mangrove removal may be delaying return of ecophysiology in Tauranga Harbour, Bay of Plenty. NIWA Client Report No. BPR802. these managed areas to a healthy ecosystem National Institute of Water and Atmospheric state (e.g. oxic layer reinstated and macrofauna Research Ltd, Hamilton, New Zealand. 68 p. re-establishment). Garbary DJ, Hansen GI, Scagel RF 1985. Additions Accurate identification of P. percursa re- to the marine algae of Barkley Sound, Vancou- quires microscopic examination as this species ver Island, British Columbia. Syesis 17: 4345. can easily be mistaken for other filamentous Green M, Ellis J, Schwarz AM, Green N, Lind D, Bluck B 2003. For and against mangrove green algae (and vice versa) in the field. Care control. NIWA Information Series 31. 8 p. must be taken to tease apart the mats that Guiry MD, Guiry GM 2012. AlgaeBase. World-wide commonly consist of tangled filaments of multi- electronic publication, National University of ple species. Ecologists must be cautious in this , Galway. http://www.algaebase.org regard if their surveys are to be accurate. (accessed 14 February 2012). Identification of P. percursa and Rhizoclonium LaingRM 1927. A reference list of New Zealand marine algae. Transactions and Proceedings of can also be confirmed via molecular identifica- the Royal Society of New Zealand 57: 126185. tion, i.e. DNA-barcoding(C.E.C. Gemmill and LaingRM 1932. List of from the coast S. Pratt, University of Waikato, unpublished near Dunedin. In: Dunedin Naturalists’ Field data). Club. Catalogue of the indigenous, and intro- duced floweringplants, ferns, and seaweeds occurringin the Dunedin district. Dunedin, Acknowledgements Mills, Dick and Co. Pp. 3141. This research was funded in part by a grant to Londry KL, Badiou PH, Grasby SE 2005. Identifi- National Institute of Water and Atmosphere cation of a marine green alga Percursaria Research (NIWA) by the New Zealand Ministry of percursa from hypersaline springs in the middle Science and Innovation (Rehabilitation of Aquatic of the North American continent. The Cana- dian Field-Naturalist 119: 8285. Ecosystems #C01X1002). Steven Pratt was funded Naylor M 1954. A check list of marine algae of the by a University of Waikato Summer Research Dunedin district. Transactions of the Royal Scholarship. We are also grateful to the two referees Society of New Zealand 82: 645663. for their constructive comments and suggestions for Neill K, D’Archino R, Farr T, Nelson W 2012. this manuscript. We thank Dr Svenja Heesch for Macroalgal diversity associated with soft sedi- providinga cultured sample, Dr Barry O’Brien ment habitats in New Zealand. New Zealand (University of Waikato, UoW) for assistance with Aquatic Environment and Biodiversity Report photography, and Rebecca Gladstone-Gallagher No. 87. 127 p. (UoW), Marenka Weis (NIWA) and Kelly Carter Park S 2004. Aspects of mangrove distribution and (UoW) for their assistance in the field. abundance in Tauranga Harbour. Environment Downloaded by [University of Waikato] at 15:01 11 April 2013 Bay of Plenty Environmental Publication No. 16. 40 p. References South GR 1984. A checklist of marine algae of Adams NM 1994. Seaweeds of New Zealand. An eastern Canada, second revision. Canadian illustrated guide. Christchurch, Canterbury Journal of Botany 62: 680704. University Press. 360 p. Wynne MJ 1986. A checklist of benthic marine BlidingC 1963. A critical survey of European taxa in algae of the tropical and subtropical western Ulvales Part I Capsosiphon, Percursaria, Blidin- Atlantic. Canadian Journal of Botany 61: gia, Enteromorpha. Opera Botanica 8: 1160. 22392281.