First Establishment of an Invasive Crayfish, Orconectes Limosus (Rafinesque, 1817) (Decapoda, Cambaridae) in Nova Scotia, Canada

FIRST ESTABLISHMENT OF AN INVASIVE CRAYFISH, ORCONECTES LIMOSUS (RAFINESQUE, 1817) (DECAPODA, CAMBARIDAE) IN NOVA SCOTIA, CANADA

SHELDON D. LAMBERT1,2), DONALD F. MCALPINE3) and ANDREW HEBDA4) 1) Cape Breton Highlands National Park of Canada, Ingonish Beach, Nova Scotia, B0C 1L0, Canada 3) Natural Science Department, New Brunswick Museum, 277 Douglas Avenue, Saint John, New Brunswick, E2K 1E5, Canada 4) Museum of Natural History, 1747 Summer Street, Halifax, Nova Scotia, B3H 3A6, Canada

BACKGROUND

No native or non-native crayfish species have been recorded in Nova Scotia, Canada. Aquatic surveys and research conducted by the Nova Scotia Museum during the past 25 years have not identified any populations of crayfish in the province. The only native species of crayfish in Maritime Canada is believed to be Cambarus bartonii (Fabricius, 1798), which, along with the non-native Orconectes limosus (Rafinesque, 1817) and Orconectes virilis (Hagen, 1870), have in the past been restricted to New Brunswick (Ganong, 1887; Crocker & Barr, 1968; McAlpine et al., 1991; McAlpine et al., 1999). The evidence presented here supports other recent information (McAlpine et al., 2007) that non-native crayfish are becoming more prevalent in the region and that this may require policy measures aimed at control. On 9 August 2005, SL observed an adult crayfish excavating a burrow on the south side of Freshwater Lake in Cape Breton Highlands National Park, Nova Scotia. Over the next three months, two shed crayfish exoskeletons were collected in the lacustrine areas of the lake. An adult crayfish was captured by SL in a shallow bay on the northeast corner of the lake on 2 September 2005. This specimen was photographed and measured (total length 81 mm). After confirming that the species was Orconectes limosus, a limited trapping program was conducted in 2006 to collect basic information about the population.

2) Corresponding author; e-mail: [email protected] © Koninklijke Brill NV, Leiden, 2007 Crustaceana 80 (10): 1265-1270 Also available online: www.brill.nl/cr 1266 NOTES AND NEWS

STUDY SITE

Freshwater Lake (46◦3840N60◦2345W) is a large lake located within the boundaries of Cape Breton Highlands National Park of Canada on Cape Breton Island, Nova Scotia (fig. 1). The lake is adjacent to the Gulf of St. Lawrence and is separated from the ocean by a rock barrier beach. The lake has a total water surface area of 42.2 hectares, a maximum depth of 16 metres, and is considered to be an oligo-mesotrophic lake (Kerekes et al., 1978). The lake has a circumneutral pH with an annual mean specific conductance of 164 µmhos/cm(Kerekesetal., 1981). Freshwater Lake also has a relatively diverse fauna for the area, with ten species of fish, a population of the unionid Pyganadon cataracta (Say, 1817), and numerous gastropods, including one of only two documented sites for Valvata sincera (Say, 1824) in the province (Davis & Wilson, 1979, NSMNH). Summer water temperatures can exceed 21◦C and below five metres winter temperatures stay above 2◦C (Kerekes et al., 1981).

Fig. 1. Freshwater Lake, Cape Breton Highland National Park, Nova Scotia, showing the locations of Orconectes limosus (Raﬁnesque, 1817) captures in the lake and inlet stream.