Dispersal of a nearshore marine fish connects marine reserves and adjacent fished areas along an open coast

Abstract

Marine species with pelagic larvae typically exhibit little population structure, suggesting long‐distance dispersal and high gene flow. Directly quantifying dispersal of marine fishes is challenging but important, particularly for the design of marine protected areas (MPAs). Here, we studied kelp rockfish (Sebastes atrovirens) sampled along ~25 km of coastline in a boundary current‐dominated ecosystem and used genetic parentage analysis to identify dispersal events and characterize them, because the distance between sedentary parents and their settled offspring is the lifetime dispersal distance. Large sample sizes and intensive sampling are critical for increasing the likelihood of detecting parent–offspring matches in such systems and we sampled more than 6,000 kelp rockfish and analysed them with a powerful set of 96 microhaplotype markers. We identified eight parent–offspring pairs with high confidence, including two juvenile fish that were born inside MPAs and dispersed to areas outside MPAs, and four fish born in MPAs that dispersed to nearby MPAs. Additionally, we identified 25 full‐sibling pairs, which occurred throughout the sampling area and included all possible combinations of inferred dispersal trajectories. Intriguingly, these included two pairs of young‐of‐the‐year siblings with one member each sampled in consecutive years. These sibling pairs suggest monogamy, either intentional or accidental, which has not been previously demonstrated in rockfishes. This study provides the first direct observation of larval dispersal events in a current‐dominated ecosystem and direct evidence that larvae produced within MPAs are exported both to neighbouring MPAs and to proximate areas where harvest is allowed.

Connectivity, Dispersal, and Recruitment: Connecting Benthic Communities and the Coastal Ocean

“…As it has become possible to determine dispersal pathways in marine populations (e.g., Baetscher et al, 2019), there has been interest in determining whether patches are demographic "sources" or "sinks. " This idea has its roots in terrestrial ecology, where patches may have a net positive (source) or net negative (sink) growth rate.…”

RAPTURE (RAD capture) panel facilitates analyses characterizing sea lamprey reproductive ecology and movement dynamics

“…For example, researchers are using genomic data in fish populations to identify genes and genomic regions associated with phenotypes and fitness in different environments (Cosart et al, 2011;Hand et al, 2016;Hohenlohe et al, 2013;Prince et al, 2017). Genotype-by-sequencing methods have also been applied in large-scale genetic pedigree reconstruction (e.g., parentage-based tagging, Anderson & Garza, 2006;Campbell, Harmon, & Narum, 2015: Beacham et al, 2017 close-kin capture-mark-release analyses, Baetscher et al, 2019) to characterize aspects of species reproductive ecology, demography, and dispersal during early life stages.…”

A GT-seq panel for walleye (Sander vitreus) provides a generalized workflow for efficient development and implementation of amplicon panels in non-model organisms

“…Finally, researchers conducting GT-seq must consider trade-offs associated with different genotyping approaches. The two main approaches we are aware of are: (1) in-silico probe-based methods that use pattern matching to genotype specific alleles (Campbell et al, 2015; McKinney et al, 2019) and (2) alignment-based methods that call all polymorphisms in a given amplicon (Baetscher et al, 2019). A major advantage of probe-based methods is that databases of probes can be shared among laboratories, facilitating standardization.…”

“…Despite its benefits, GT-seq is not yet widely used outside of salmonids. Early applications to non-model organisms, however, have shown great promise for this method’s versatility, including the ability to reveal dispersal and mating patterns in a complex environment (Baetscher et al, 2019), provide insight to the ecological and evolutionary dynamics of secondary contact (Reid et al, 2019), and understand population diversity in systems that are heavily influenced by climate change (Pavinato et al, 2019). Pedigree analysis in wild populations is highly dependent upon the ability to genotype large sample sizes to increase the likelihood of detecting kin relationships, toward which GT-seq is ideally suited.…”