Going global: The introduction of the Asian isopod Ianiropsis serricaudis Gurjanova (Crustacea: Peracarida) to North America and Europe

Abstract

Cladophora is a genus of branched filamentous green algae (Ulvophyceae). It contains many species that are challenging to differentiate based on morphology because of the scarcity of diagnostic characters and extensive phenotypic plasticity. Within the past five years, Cladophora blooms have been observed on the ropes of green-lipped mussel farms in the Marlborough Sounds, New Zealand. When Cladophora reaches high biomass, it can clog mussel-harvesting equipment; thus, it is considered a nuisance organism in the region. This study used morphological and molecular techniques to identify the species responsible for the blooms, and to investigate whether this might be a recent incursion. Cladophora samples (n = 21) were collected from nine mussel farms, one salmon farm, and a marina. Morphological and phylogenetic analyses (partial large subunit and internally transcribed spacer regions 1 and 2 of the nuclear ribosomal cistron), revealed the identity of the bloom forming species as Cladophora ruchingeri (C.Agardh) Kützing, 1845. This represents the first report of this species in the Southern Hemisphere and Pacific region. Given the distinct morphology of C. ruchingeri (when mature), its absence from previous surveys of macro-algae from this region, and increasing reports of blooms, our findings suggest that this species has only recently been introduced to New Zealand. This study provides a robust taxonomic identification and initial baseline data. Further directed studies on Cladophora are required to advance knowledge on its ecology and distribution in New Zealand, and assist in the development of mitigation strategies.

First record of Ianiropsis cf. serricaudis in Maryland Coastal Bays, USA (Crustacea, Peracarida, Janiridae)

“…Unfortunately, the original description is poor and the illustrations are incomplete (Gurjanova 1936). Specimens of I. serricaudis have also previously been reported in the Sea of Okhotsk, on the Coast of Iturup Island (one of the Kuril Islands) from Russia (Kussakin 1962, 1988), Korea (Jang and Kwon 1990), and recently as a successful invasive species of both coasts of the United States and Europe (Hobbs et al 2015; Marchini et al 2016; Ulman et al 2017) (Fig. 1).…”

“…Ianiropsis serricaudis – type material (green circle), I. serricaudis – additional records (red circle), I. cf. serricaudis (yellow square). Data from: Gurjanova (1936); Kussakin (1962, 1988); Jang and Kwon (1990); Hobbs et al (2015); Marchini et al (2016); Ulman et al (2017); Morales-Núñez and Chigbu (this study).…”

“…For this reason, identification of the specimens from this study is based on the morphological characters from previous descriptions (Gurjanova 1936; Kussakin 1962, 1988; Jang and Kwon 1990; Hobbs et al 2015). …”

“…1). In the coastal waters of the northeastern United States, it has only been reported from Gulf of Maine to Barnegat Bay, NJ whereas in Europe it is known only from England, Netherlands, Italy, and France (Hobbs et al 2015; Marchini et al 2016; Ulman et al 2017) (Fig. 1).…”

“…1). These authors presented additional descriptions of the body and/or appendages of specimens of the species and showed morphological differences among specimens from various geographic locations (see Kussakin 1962, 1988; Jang and Kwon 1990; Hobbs et al 2015). Additionally, Saito et al (2000) considered I. notoensis as a junior synonym of I. serricaudis despite exhibiting multiple differences with Gurjanova’s original description.…”