Going down together: invasive host, Charybdis longicollis (Decapoda: Brachyura: Portunidae) and invasive parasite, Heterosaccus dollfusi (Cirripedia: Rhizocephala: Sacculinidae) on the upper slope off the Mediterranean coast of Israel

ABSTRACT

The swimming crab Charybdis longicollis, native to the western Indian Ocean, was first recorded in the Mediterranean in 1954. It is now established from Egypt to Greece, and dominates the sandy-mud bottoms at 25–80 m in the southeastern Mediterranean. The success of C. longicollis is attributed to its high fecundity, agonistic behaviour and omnivorous diet, as well as the rise in seawater temperature. Since the early 1990s its populations in Israel and Turkey have been heavily parasitized by the alien rhizocephalan Heterosaccus dollfusi, which impacts its host’s behaviour, growth and fecundity, and causes mortality. Yet, 60 years after its first record in the Mediterranean, the population of C. longicollis seems durable, and has recently spread to the lower shelf and upper slope off Israel, where it is common at 80 m and is found down to 250 m, greatly increasing its spatial spread. The maximal percentage of parasitization was 87.2%, 88.8%, 75.5% and 81.8% at depths of 40, 60, 80, 100 m, respectively, and 50% at 120 and 250 m. Here, we hypothesize on the possible contribution of the depletion of its putative fish predators, mainly rays, to the prevalence of C. longicollis on the lower shelf.

RESPONSIBLE EDITOR:

• Ingo Wehrtmann

KEYWORDS:

• Parasitization
• population biology
• Enemy Release Hypothesis
• Crustacea
• Charybdis longicollis
• Heterosaccus dollfusi

Acknowledgements

The authors thank Levy Ornoy, Captain of the FV ‘Moti’, for his endless patience and kind hospitality, and Hana Bernard for preparing the map illustration. The authors are grateful to the anonymous reviewers for their helpful comments on previous versions of the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Gianna Innocenti http://orcid.org/0000-0002-4504-0765

Gianluca Stasolla http://orcid.org/0000-0002-8404-8794

Bella S. Galil http://orcid.org/0000-0002-9268-7211

Additional information

Funding

Partial support for this research was provided by the European Community’s Seventh Framework Programme FP7-OCEAN-2010; proposal no. 266445 for the project Vectors of Change in Oceans and Seas Marine Life, Impact on Economic Sectors (VECTORS) and Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential (COCONET) (BSG).