Ocean Indicators Predict Range Expansion of an Introduced Species: Invasion History of the European Green Crab Carcinus maenas on the North American Pacific Coast

Abstract Major El Niño events and oceanic heat waves are linked to the range expansion of many marine species. For the shores of the northeast Pacific, we compared range expansion in the European green crab, Carcinus maenas, which was introduced to San Francisco Bay prior to 1990, to that of the native lined-shore crab, Pachygrapsus crassipes, which has existed on the coast since at least the end of the last Ice Age (>10,000 years ago). The initial northern range limit of these species was central California and central Oregon, respectively. Both species increased their northern range along the open coast to northern Oregon, Washington and Vancouver Island after strong El Niño events. C. maenas, however, in just a matter of decades, successfully established populations in inlets on the west coast of Vancouver Island, and possibly also in the Salish Sea, while P. crassipes, in thousands of years, never has. We hypothesize that this difference in invasion success is due to the shorter larval duration of C. maenas, < 2 months, compared to that of P. crassipes, 3-4 months and timing of larval release, winter for both species. Because the residency times of water in the inlets of the west coast of Vancouver Island are ~1-2 months, they can act as an incubator for the larvae of C. maenas, while those of P. crassipes are likely flushed out to the open sea before they can complete their development.

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Northward range expansion of the European green crab Carcinus maenas in the SW Atlantic: a synthesis after ~20 years of invasion history

10.1101/2020.11.04.368761 ◽

2020 ◽

Author(s):

Mariano E. Malvé ◽

Marcelo M. Rivadeneira ◽

Sandra Gordillo

Keyword(s):

Native Species ◽

Species Distribution Model ◽

Carcinus Maenas ◽

Distribution Model ◽

Invasion History ◽

Biogeographic Provinces ◽

History Of ◽

European Green Crab ◽

Sw Atlantic ◽

Northward Expansion

AbstractThis study aims at synthesizing the recent invasion history of Carcinus maenas in the SW Atlantic (~20 years), particularly the northward expansion, based on available published papers, technical reports, and new field surveys. Our analyses extend the known distribution range northwards ca. 330 km. totaling ~1000 km along the Argentinean coast since its last detection in Nuevo Gulf in 2015. The expansion rate appeared to slow down during the last 15 years (from 115km/yr. to 30 km/yr.) as the species continues moving northwards into the transition zone between the Magellan and Argentinean biogeographic provinces (41°–43°S). In addition, a species distribution model (SDM) is provided at a much finer spatial resolution than previous studies, which accurately foresees suitable areas of invasion in the southern San Jorge Gulf, and predicts a hotspot of invasibility around 40°–33°S° if the invasion continues northward. Potential impacts of C. maenas on native species, particularly economically important oyster beds are discussed.

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