Diet and population biology of the invasive crabCharybdis helleriiin southwestern Atlantic waters

Abstract

For many species the population structure varies along latitudinal gradients, especially at the extremes of their distributions. This may apply to invasive species, whose ability to grow, reproduce, feed and compete is hypothesized to be lower at higher latitudes. A population of Charybdis hellerii was investigated on a rocky shore at Armação do Itapocoroy (Santa Catarina, 26°4 0′-26°47′S and 48°36′-48°38′W), Brazil. The study was carried out over two periods to test the hypotheses that: (1) this population differs from other populations that presumably became established earlier and at lower latitudes; (2) the population parameters change over time (number and size of individuals and ovigerous females), progressively showing more indications of establishment; and (3) the diet overlaps with the native crabs. In total, 642 individuals were caught: 544 males, 55 females, and 43 ovigerous females. This population of C. hellerii is similar to others presumably established earlier and at lower latitudes on the Atlantic coast, with a predominance of larger males and a male-biased sex ratio. The population is reproducing, but the similarity in the population size and frequency of ovigerous females between periods may indicate that this population is encountering difficulty in increasing in size. The generalist diet was composed mainly of crustaceans, molluscs and algae, thus overlapping with other native crab species. Although the direct and indirect impacts of this invasive species were not assessed, the population parameters indicate that this population of C. hellerii is established and may act as a centre of dispersal to higher latitudes.

Metagenomes of a Freshwater Charavirus from British Columbia Provide a Window into Ancient Lineages of Viruses

“…The consistent linkage of the charavirus CPs to a homolog isolated from a swimming crab, Beihai Charybdis crab virus 1, is of interest. This virus is possibly a contaminant, rather than a virus of Charybdis crabs, as, although these crabs are opportunistic carnivores, they do eat algae [54], and although most charophytes inhabit freshwater, some also live in brackish water [55], where they might be eaten by crabs. However, in the k-mer analyses, the BCCV1 CP did not group with the CV CPs, indicating that its host is probably not a charophyte.…”

Applying geometric morphometrics in megalopa larval stages: relevance for species distribution and biological invasion studies

“…Successful invasive crabs are often characterized by a great dispersal capability, high environmental tolerance, uncommon morphology, and a wide range of potential prey items (Gherardi, 2006;Baiser et al, 2010;Zhang et al, 2010). These are typical in most of the harmful global invasive brachyuran crabs, including C. maenas (Elner, 1981;Siegenthaler et al, 2022), C. sapidus (Prado et al, 2022) or C. hellerii (Sant' Anna et al, 2015). Indeed, C. ruber presents many of these traits (Triay-Portella et al, 2022).…”

Predation on the invasive swimming crab Charybdis hellerii (Crustacea, Decapoda) by Myrichthys ocellatus (Actinopterygii, Ophichthidae): the first record of consumption by a native fish

“…This species spread along the Caribbean in the following years, probably transported by ballast water and local currents [14,15]. The rapid growth, continuous reproduction, along with the generalized habitat and diet requirements of C. hellerii, allowed a successful establishment and spread of this IAS, which is now found in virtually the entire Brazilian coast, from Pará to Santa Catarina states [13,16].…”

“…In some Brazilian states (e.g. São Paulo and Santa Catarina), C. hellerii has outnumbered local crab populations, competing for resources with native species [4,16]. The use of this invasive crab in local fisheries is minimal; for example, in Venezuela (Falcón State), C. hellerii represented 5% of the captures in crab artisanal fisheries in 2003-2004 [18].…”