MEPS 753:85-104 (2025)  -  DOI: https://doi.org/10.3354/meps14777

ABSTRACT: Life history traits affecting dispersal ability could affect species’ responses to climate change. Size-specific abundances of 4 NE Pacific Littorina snail species (2 with planktonic eggs and larvae [planktonic development, PD] and 2 with direct development [DD] from attached egg masses) were compared on 2 rocky intertidal sites near Bamfield on Vancouver Island, British Columbia, Canada, between 1994 and 2021. Two very strong El Niño-Southern Oscillation events (1997/1998 and 2015/2016) were followed by large, significant increases in recruitment of 2 PD species. By contrast, the juvenile recruitment of the common DD species showed varied responses to the first event and a large, significant decrease during the second event. Four hypotheses explaining the effect of the developmental mode on recruitment after very strong El Niño events were evaluated. Two of these hypotheses, (H₁) interspecific competition and (H₂) selective predation of the thin-shelled DD species by a temporarily invading lined shore crab from southern Oregon, USA, were rejected. Alternative hypotheses were that the larval supply and/or juvenile survival of the PD species increased because of (H₃) higher summer sea surface temperature (SST) or (H₄) stronger winter poleward currents and higher minimum winter SST. H₄ was strongly supported by the significant positive ‘slope’ coefficients for the covariate ‘previous February SST’ within multivariate autoregressive state-space models of the July and December juvenile PD count anomalies. The northward winter Davidson surface current is faster and warmer during very strong El Niño events, which may increase the larval transport and subsequent intertidal recruitment of the PD species.

KEY WORDS: Abundance patterns · California Current · Coastal Kelvin wave · Direct development · Larval transport · Long-term data series · Sea surface temperature · Time-series modelling

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Cite this article as: Boulding EG (2025) Presence or absence of a planktonic egg and larval stage affects the intertidal recruitment of Littorina species (Gastropoda) during very strong El Niño events. Mar Ecol Prog Ser 753:85-104. https://doi.org/10.3354/meps14777 Export citation Share:    Facebook - - Bluesky - linkedIn