High Interannual Variability in Connectivity and Genetic Pool of a Temperate Clingfish Matches Oceanographic Transport Predictions

Abstract

Adults of most marine benthic and demersal fish are site-attached, with the dispersal of their larval stages ensuring connectivity among populations. In this study we aimed to infer spatial and temporal variation in population connectivity and dispersal of a marine fish species, using genetic tools and comparing these with oceanographic transport. We focused on an intertidal rocky reef fish species, the shore clingfish Lepadogaster lepadogaster, along the southwest Iberian Peninsula, in 2011 and 2012. We predicted high levels of self-recruitment and distinct populations, due to short pelagic larval duration and because all its developmental stages have previously been found near adult habitats. Genetic analyses based on microsatellites countered our prediction and a biophysical dispersal model showed that oceanographic transport was a good explanation for the patterns observed. Adult sub-populations separated by up to 300 km of coastline displayed no genetic differentiation, revealing a single connected population with larvae potentially dispersing long distances over hundreds of km. Despite this, parentage analysis performed on recruits from one focal site within the Marine Park of Arrábida (Portugal), revealed self-recruitment levels of 2.5% and 7.7% in 2011 and 2012, respectively, suggesting that both long- and short-distance dispersal play an important role in the replenishment of these populations. Population differentiation and patterns of dispersal, which were highly variable between years, could be linked to the variability inherent in local oceanographic processes. Overall, our measures of connectivity based on genetic and oceanographic data highlight the relevance of long-distance dispersal in determining the degree of connectivity, even in species with short pelagic larval durations.

Past climate changes and strong oceanographic barriers structured low‐latitude genetic relics for the golden kelp Laminaria ochroleuca

“…(), Klein et al. () and Cunha et al. (), with daily data from the Hybrid Coordinate Ocean Model (HYCOM; Chassignet et al., ).…”

“…This period covers the reproductive stages that can potentially fragment and drift, releasing spores after dispersal (Clarkin et al, 2012;Thiel & Gutow, 2005) even when rafting for long time (Macaya et al, 2005). Particles were allowed to drift until reaching shore, and their position was determined hourly with bilinear interpolation on the velocity fields of currents (Cunha et al, 2017;Klein et al, 2016). As real dispersal times of L. ochroleuca are unknown, different simulations were performed with contrasting thresholds of: 1 day, for dispersal by spores, as sporulation lasts 15-18 h (Pereira et al, 2011), and spores stop swimming after~24 h (inferred for Macrocystis pyrifera and Pterygophora californica; Reed et al, 1992); 30 days, considering long-lived rafts, in line with the period estimated for other brown algae (Monteiro, Paulino, Jacinto, Serrão, & Pearson, 2016;Thiel & Gutow, 2005); 60 days, for longer-lived rafts.…”

“…Dispersal predictions are increasingly compared with genetic estimates, but not along species ranges (e.g., Alberto et al., ; Billot, Engel, Rousvoal, Kloareg, & Valero, ; Buonomo et al., ; Coleman, ). Species with restricted dispersal generally hold fine‐scale genetic differentiation (e.g., seaweeds: Assis et al., ; Neiva, Pearson, Valero, & Serrão, ; Robuchon, Le Gall, Mauger, & Valero, ), while those with larger dispersal probabilities (having larval stages) tend to have variable or little phylogeographic structure (e.g., mussels: Lourenço et al., ; pelagic fish: Silva et al., ; benthic fish: Klein et al., ). In benthic marine organisms, depth range shifts, the equivalent to terrestrial altitudinal shifts, may further permit long‐term persistence of ancient gene pools.…”

Evidence for interannual variation in genetic structure of Dungeness crab (Cancer magister) along the California Current System

“…Therefore, both local recruitment and large‐scale dispersal may play distinct roles in shaping genetic connectivity of this species, as in Klein et al. ().…”

“…These analyses focus on how genetic variation within populations is distributed among individuals and have contributed to a growing paradigm that local processes (e.g., kin aggregation, retention) play important roles in regulating genetic connectivity alongside large‐scale processes (e.g., dispersal) (Christie et al., ; Klein et al. ; Pusack et al., ; Underwood, Travers, & Gilmour, ).…”