Self-recruitment and sweepstakes reproduction amid extensive gene flow in a coral-reef fish

Department of Zoology, Oregon State University, Corvallis, OR 97331-2914, USA.
Molecular Ecology (Impact Factor: 5.84). 03/2010; 19(5):1042-57. DOI: 10.1111/j.1365-294X.2010.04524.x
Source: PubMed

ABSTRACT Identifying patterns of larval dispersal within marine metapopulations is vital for effective fisheries management, appropriate marine reserve design, and conservation efforts. We employed genetic markers (microsatellites) to determine dispersal patterns in bicolour damselfish (Pomacentridae: Stegastes partitus). Tissue samples of 751 fish were collected in 2004 and 2005 from 11 sites encompassing the Exuma Sound, Bahamas. Bayesian parentage analysis identified two parent-offspring pairs, which is remarkable given the large population sizes and 28 day pelagic larval duration of bicolour damselfish. The two parent-offspring pairs directly documented self-recruitment at the two northern-most sites, one of which is a long-established marine reserve. Principal coordinates analyses of pair-wise relatedness values further indicated that self-recruitment was common in all sampled populations. Nevertheless, measures of genetic differentiation (F(ST)) and results from assignment methods suggested high levels of gene flow among populations. Comparisons of heterozygosity and relatedness among samples of adults and recruits indicated spatially and temporally independent sweepstakes events, whereby only a subset of adults successfully contribute to subsequent generations. These results indicate that self-recruitment and sweepstakes reproduction are the predominant, ecologically-relevant processes that shape patterns of larval dispersal in this system.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The largely endemic cichlid species flocks of the East African Great Lakes are among the prime examples for explosive speciation and adaptive radi-ation. Speciation rates differ among cichlid lineages, and the propensity to radiate has been linked to intrinsic and extrinsic factors such as sexual selection and ecological opportunity. Remarkably, only one cichlid tribe—the Boulengerochromini—comprises just a single species, Boulengerochromis microlepis, a predominantly piscivorous endemic of Lake Tang-anyika and the world's largest cichlid. While the lineage diverged from its closest relatives at the onset of the Lake Tanganyika radiation [8 MYA, mito-chondrial control region sequences collected in this study dated the most recent common ancestor of B. microlepis to *60–110 KYA. There was no evidence of phylogeographic structure in the lake-wide sample. Patterns of genetic diversity and demographic analyses were consistent with slow and steady population growth throughout the reconstructed timescale. Addi-tionally, the shallow divergence within the species may be related to a possibly large variance in reproductive success in this highly fecund species. Trophic niche space restriction by sympatric pisci-vores, lack of geographic structure, low potential for sexual selection arising from the monogamous mating system and extinction may have contributed to keep-ing the lineage monotypic.
    Hydrobiologia 04/2015; 748:29-38. DOI:10.1007/s10750-014-1863-z · 2.21 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Using calcified structures as natural geochemical tags to estimate levels of population connectivity is becoming increasingly common. However, the technique suffers from several logistical and statistical problems that constrain its full application. Foremost is that only a subset of potential sources is sampled, often compounded by under-sampling within locations at an overly coarse spatial scale. This introduces unknown error and prevents the creation of a rangewide connectivity matrix. To address this issue, we analyzed the natural geochemical tags of embryonic statoliths in the whelk Kelletia kelletii (Forbes, 1850). We sampled from 23 sites over the entire geographic range in 2004 and 2005 from Monterey (California, USA) (36°N) to Isla Asunción, (Baja California, Mexico) (27°N). We then used geospatial statistics (kriging) to make continuous along-coast maps of embryonic statolith chemistry. This allowed us to estimate chemistry at unsampled locations. We used this new continuous assignment method to estimate the spatial error associated with assignment by the classic method of discriminant function analysis (DFA). Then, we compared the performance of the 2 methods at classifying unknown embryonic statoliths. We found large spatial errors often associated with DFA assignments, even when traditional DFA accuracy assessments indicated the method was performing well. The continuous method provided an improved assessment of uncertainty in assignments. It outperformed the DFA method in classifying unknown embryos to the vicinity of their true source. Geospatial statistics also provided useful information on other range-wide variables, such as adult reproductive abundance. As a proxy for larval supply, such information can aid future assignments of recruits. Our combined analyses help inform sampling designs and motivate the development of a new approach for population connectivity studies.
    Marine Ecology Progress Series 08/2014; 508:33-51. DOI:10.3354/meps10871 · 2.64 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Many organisms can alternatively expand their range through long-and short-distance movements. Understanding the relative importance of these two strategies in determining species range size is of great interest in ecology and conservation biology. The more distant species move, the lower their probability of finding suitable conditions for survival. Thus, a species has a lower probability to succeed in colonization through long-distance dispersal than through short-distance dispersal, i.e., a tradeoff exists between the two strategies. Here, I investigate this issue by using a spatially explicit model where species move from patch to patch across a fragmented landscape. By analyzing the outcomes of 10,000 simulations run on the model under a wide range of tradeoff scenarios, I identified colonization ability as the strongest predictor of species range, followed by short distance dispersal ability, short distance colonization ability and long distance dispersal ability. Thus, range size of species having two different movement strategies is mainly determined by how far the species can move in the short distance strategy, and by its likelihood to succeed in colonization of distant localities, even if the dispersal/colonization tradeoffs between the two strategies are very small. ã 2014 Elsevier B.V. All rights reserved.
    Ecological Modelling 11/2014; 297:80-85. DOI:10.1016/j.ecolmodel.2014.11.011 · 2.33 Impact Factor

Full-text (4 Sources)

Available from
May 26, 2014