First record of the invasive swimming crab Charybdis hellerii (A. Milne Edwards, 1867) (Crustacea, Portunidae) off Martinique, French Lesser Antilles

Abstract

The giant garden slug Limax maximus Linnaeus, 1758 (Limacidae, Pulmonata) is considered one of the most widely spread terrestrial molluscs in the world and is a formidable pest of agricultural and horticultural crops. This slug was recently introduced to Japan, where its population is now rapidly increasing and spreading. A naturalised population of L. maximus was first discovered in Hokkaido, Japan, in 2012 in the isolated natural forest of Maruyama Forest Park in Sapporo City, and the species has become common in this area. In the present study, we investigated observations of L. maximus reported by ordinary citizens acting as "citizen scientists" to assess the recent expansion of this invasive slug. We posted an announcement in the local newspaper requesting reports of the occurrence of L. maximus via e-mail and analysed 38 observations provided by local citizens. As a result of these reports, 16 naturalised populations of L. maximus were detected in Hokkaido, several of which were quite far from the original population in Sapporo City. Moreover, a terrestrial macrophagous leech, Orobdella kawakatsuorum Richardson, 1975 (Arhynchobdellida, Orobdellidae), is reported as a potential native predator of L. maximus for the first time.

Short Communication: Biological aspects of Charybdis anisodon (De Haan, 1850) in Lasongko Bay, Central Buton, Southeast Sulawesi, Indonesia

“…Mann-Whitney test of carapace width and length of C. anisodon showed a significantly different (p<0.05) between males and females (Table 2). Body size (carapace width and length) of male was larger than females, and this is identical to those found in some other species of Charybdaris, such as C. feriatus (Dineshbabu 2011;Dash et al 2014), C. natator (Sumpton 1998; Sallam and Gab-Alla 2010; Vidhya 2016), C. bimaculata (Doi et al 2008), C. hellerii (Ozcan et al 2010;Sant'Anna et al 2012;Ferry et al 2017) and C. japonica (Fowler 2011;Wong 2013).…”

“…The carapace width of ovigerous female C. anisodon found in this study was larger than that of ovigerous female C. hellerii, i.e. 3.82 cm (Ferry et al 2017), but smaller than that of C. japonica, i.e. 6.25+0.24 cm (Wong 2013) and C. natator, i.e.…”

“…In Lasongko Bay, the male C. anisodon was dominated by the 5.09-5.59 cm carapace width class size, while the female was dominated by the 4.07-4.57 cm carapace width class size ( Figure 2). The carapace width class size distribution of male and female C. hellerii in Martinique, French was dominated by the 3.70-3.95 cm class size (Ferry et al 2017), while Ozcan et al 2010found the dominant class size was 6.1-7.0 cm in males and 5.1-6.0 cm in female for the same species in Iskenderun Bay, Turkish.…”

“…Among the species of the genus Charybdis, C. anisodon, C. hellerii and C. japonica are categorized as small-sized species while C. natator, C. bimaculta and C. feriatus are the large-sized ones. The carapace width of male C. hellerii ranged between 2.5 and 7.8 cm and female ranged between 1.73 and 6.50 cm (Ozcan et al 2010;Bolanos et al 2012;Sant'Anna et al 2012;Ferry et al 2017), carapace width of male C. japonica ranged between 2.8 and 10.37cm and female ranged between 2.8 and 9.9 cm (Fowler 2011; Wong 2013). The maximum carapace width of C. feriatus and C. natator reached 20 cm and 17 cm, respectively (Ng 1998), and carapace width of the male C. bimaculata ranged between 5.35 and 24.14 cm and the female ranged between 4.94 and 20.75 cm (Doi et al 2008).…”

“…From biological point of view, information on the size distribution, the relationships between carapace sizes and body weight, sex ratio, first-sex maturity and spawning season are needed in sustainable crab fisheries management (Kamrani et al 2010;Ikhwanuddin et al 2012, Hamid et al 2016b. Researches on biological aspect of the genus Charybdis have been carried out on C. natator (Sumpton 1990; Sallam and Gab-Alla 2010; Kannathasan and Rajendran 2011; Vidhya 2016), C. affinis (Chu 1999), C. hellerii (Mantelatto and Garcia 2001, Sant'Anna et al, 2012, Ferry et al, 2017, C. bimaculata (Doi et al 2010), C. feriatus (Dineshbabu 2011;Nieves et al, 2015) and C. japonica (Fowler 2011;Wong. 2013), but it is lacking in C. anisodon.…”