Unintended backpackers: bio-fouling of the invasive gastropod Rapana venosa on the green turtle Chelonia mydas in the Río de la Plata Estuary, Uruguay

Abstract

Here we report the first observations of the rapa whelk Rapana venosa massively bio-fouling immature green turtles Chelonia mydas. From November 2004 to July 2011, we examined 33 green turtles with rapa whelks attached to their carapaces in Uruguayan waters. The number of attached rapa whelks ranged from 1 to 49 individuals, representing up to 20 % of turtle weight. This previously unrecorded interaction may be of global importance to green turtles conservation because (a) immature green turtles from distant breeding populations utilize insular and coastal waters of the Río de la Plata estuary and Atlantic coast of Uruguay as developmental and foraging habitats and (b) attached whelks may reduce green turtle fitness by reducing buoyancy, increasing drag, and causing severe injuries to the carapace.

Non-native mollusks throughout South America: emergent patterns in an understudied continent

“…Rapana venosa (Muricidae) or rapa whelk, was probably introduced in the Río de la Plata River during the late 1980s via larvae transported in ballast water (Pastorino et al 2000;Orensanz et al 2002) (Online Resource 3). Reported impacts in South America include probable depletion or reduction of at least some prey population (e.g., mussels) (Carranza et al 2009) and massive fouling on immature green turtles Chelonia mydas (Linnaeus, 1758) (Lezama et al 2013). On the other hand, the rapa whelk may constitute up to 100% of the diet for immature and mature logger heads, Caretta caretta (Linnaeus, 1758), and at least a minor item in the diet of the small shark Mustelus schmitti Springer, 1939 (Bonelli et al 2016).…”

Determining body condition of nesting loggerhead sea turtles (Caretta caretta) in the South-west Indian Ocean

“…Ultimately, turtle health can be compromised by increased weight and drag, which in some cases is excessively large. For example, green turtles in Uruguay were found to have biofouling from an invasive gastropod ( Rapana venosa ) that accounted for up to 20% of the turtle's mass (Lezama et al ., 2013). For reproductive females, the associated cumulative energetic cost is particularly compromising during long migrations of thousands of kilometres between feeding and nesting habitats.…”

Incorporation of Rapa Whelk (Rapana venosa) meal in diets for rainbow trout (Oncorhynchus mykiss) fry

“…Concerning the invasive features of R. venosa, the European Union Parliament reported its negative effects on the blue mussel ( Mytilus galloprovincialis ) and the striped venus ( Chamelea gallina ) populations that the precautionary solutions must be taken in response to predation pressure, which poses a significant threat to the ecological balance (Anonymous, 2011). Other studies also indicate several serious adverse effects of R. venosa on green sea turtle Chelonia mydas (Lezama et al., 2013; Spotorno‐Oliveira et al., 2020) or bivalve species such as Mactra isabelleana, Ostrea puelchana (Spotorno‐Oliveira et al., 2020), Ostrea edulis and Flexopecten glaber (Chukhchin, 1961; Drapkin, 1963). Bringing in the snails that are discarded by processing facilities could have a positive economic impact; moreover, the invasive nature of the species also supports the idea that this animal can be used in fish feeds instead of fishmeal (Sahin et al., 2018).…”