Tane 35: 121 - 125 (1995)

ASPEROCOCCUS BULLOSUS - A NEW RECORD FOR NORTHERN NEW ZEALAND OF AN ADVENTIVE MARINE BROWN ALGA

by Wendy A. Nelson and Glenys A. Knight Museum of New Zealand Te Papa Tongarewa, P O Box 467, Wellington

INTRODUCTION

In November 1994 thalli of the brown seaweed Asperococcus bullosus Lamouroux (Dictyosiphonales, Punctariaceae) (Fig. 1) were found washed ashore in the drift at Kotiatia Point near Rangiputa, at the eastern entrance to the Rangaunu Harbour, in Rangaunu Bay (Fig. 2). This is the first record of this species for the North Island.

Previous distribution and records in NZ Asperococcus bullosus was first recorded in New Zealand waters from Stewart

Island by Lindauer (1957) who described it as "sausage-shaped and thin skinned". In summer months it is found in the drift on the beach at Oban. The first records for the South Island were collected from sites within the Marlborough Sounds in the late 1980s and early 1990s (Mikhail Lermontov wreck, Port Gore, C. Hay, 1988, W E L T A19130; Nikau Bay, Pelorus Sound, L . Rhodes, 1989, Cawthron Institute; Hallam Cove, Tawhitinui Reach, Pelorus Sound, C. Duffy, 1990, W E L T A19063).

Description of species Asperococcus bullosus is characterised by a simple, erect, hollow thallus that

tapers at the base and has a rounded apex. It is golden to mid-brown in colour and has a characteristic spotted appearance. A. bullosus has an inner medulla of large colourless cells and an outer cortex of small pigmented cells, each with several discoidal plastids containing pyrenoids. Phaeophycean hairs are borne singly or in clusters, each with a basal meristem and sheath. Sporangia arise from surface cells and they are usually associated with short, clavate, multicellular paraphyses.

European and Australian records This species is native to Europe, and has been referred to as A. bullosus on

the Continent (Cabioc'h et al. 1992) and as A. turneri in Britain (Fletcher 1987; Morton 1994). The name A. bullosus has priority as explained by Womersley (1987) "According to Stafleu & Cowan (1979:741), A. bullosus

Fig. 1. Asperococcus bullosas collected at Kotiatia Point, Rangaunu Harbour, November 1994 (WELT A21053).

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Fig. 2. Map of the northern North Island showing Rangaunu Harbour and the collection area.

Lamouroux 1813 was published in August and Ulva turneri Dillwyn in Smith & Sowerby has the plate dated Nov 1, 1813, with the volume published between 1 March 1813 and 1 March 1814 (pi. 2592)".

Three species of Asperococcus have been recorded as adventive species in Australia (Womersley 1987):

A. bullosus - found from Rottnest Island (Western Australia) to Pittwater, Sydney (NSW) and also on the north and east coasts of Tasmania; A. compressus - known solely from Flinders and Port Phillip (Victoria); A. fistulosus - found on Kangaroo Island (South Australia) to Apollo Bay (Victoria), and in south-eastern Tasmania.

Seasonality/ ecology In Britain and Europe A. bullosus is a summer annual plant growing in

sheltered waters, usually epilithic but occasionally epiphytic, as for example on Posidonia in the Mediterranean (Fletcher 1987; Cabioc'h et al. 1992). In Australia A. bullosus is typically epiphytic on the seagrasses Posidonia and Amphibolis, and is usually found in shallow sheltered waters, although it has been

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found extending to 22m. Many of the plants found at Rangaunu Harbour were attached to fragments

of Zostera. Presumably strong winds from the north and east had stirred up the Zostera beds, causing the inflated thalli of Asperococcus to tear away and then to be cast ashore.

DISCUSSION

Adams (1983) listed A. bullosus as an adventive seaweed, along with other marine macroalgae that had been recorded in New Zealand from a number of harbour and mooring areas, both those in modern usage and others which were used in the times of the whaling and sealing operations of last century. Although the first record of A. bullosus was this century it is quite possible that the species was in Stewart Island for some time before its discovery.

In Europe this species has a life history in which the macroscopic phase alternates with a microthallus stage. The microscopic phase is unknown in Australia, where the species exhibits a direct life history - that is, spores produced by the macroscopic phase developing into more macroscopic thalli (Clayton 1982, as A. turneri). No life history studies of New Zealand populations have been carried out to date and thus it is not possible to speculate whether the plant travelled to New Zealand as a microscopic gametophyte or macroscopic sporophyte.

The subsequent records of Asperococcus in New Zealand may be from translocation of this species from the Stewart Island population, or may be new and separate introduction events, either from the native range of this species, or from another part of the species adventive range (Australia). The discovery of A. bullosus plants at the wreck of the cruise ship Mikhail Lermontov suggests that these plants were being transported by this ship. The records from other parts of the Marlborough Sounds may be due to quite separate introductions or translocation events. The Rangaunu Harbour is very distant from these southern sites and no records of pleasure craft and fishing vessels link the northern record to the Marlborough Sounds or Stewart Island sites. Studies of the adventive kelp Undaria pinnatifida in major fishing ports and harbours have clearly shown the importance of coastal shipping in the translocation of this species around the New Zealand coastline (Hay 1990).

The application of molecular 'fingerprint' methods, such as plastid D N A mapping, to determine relationships between populations has recently yielded interesting information about the possible origins of adventive populations (Goff et al. 1992). A comparison of populations in Stewart Island, Port Gore and other Marlborough Sound sites, and Rangaunu Harbour populations, with material from

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Europe and Australia may provide an insight into the relationships between these disjunct populations with human-mediated distributions.

REFERENCES

Adams, N.M. 1983: Checklist of marine algae possibly naturalised in New Zealand. New Zealand Journal of Botany 21: 1-2.

Cabioc'h, J., Floc'h, J-Y., Le Toquin, A. , Boudouresque, C-F., Meinesz, A. & Verlaque, M. 1992: "Guide des Algues des Mers D'Europe." Delachaux et Niestle, Paris. 231pp.

Clayton, M.N. 1982: Life history studies in the Ectocarpaceae (Phaeophyta): Contributions toward the understanding of evolutionary processes. Botanica Marina 25: 111-116.

Fletcher, R.L. 1987: "Seaweeds of the British Isles. Volume 3: Fucophyceae (Phaeophyceae) Part 1." British Museum (Natural History), London. 359pp.

Goff, L.J . , Liddle, L . , Silva, P.C., Voytek, M . , & Coleman, A.W. 1992: Tracing species invasion in Codium, a siphonous green alga, using molecular tools. American Journal of Botany 79: 1279-1285.

Hay, C.H. 1990. The dispersal of sporophytes of Undaria pinnatifida by coastal shipping in New Zealand, and implications for further dispersal of Undaria in France. British Phycological Journal 25: 301-313.

Lindauer, V.W. 1957: A descriptive review of the Phaeophyceae of New Zealand. Transactions of the Royal Society of New Zealand 85: 61-74.

Morton, O. 1994: "Marine Algae of Northern Ireland." Ulster Museum, Belfast. 123pp. Stafleu, F.A. & Cowan, R.S. 1979: Taxonomic Literature. 2nd Ed., Vol. II, H-Le. Regnum

Vegetabile 98: 1-991. Womersley, H.B.S. 1987: "The Marine Benthic Flora of Southern Australia Part II." South

Australian Government Printing Division, Adelaide. 484pp.

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