Overview and Current Trends in Studies on the Evolution and Phylogeny of Anguilla

Pujolar, José Martín; Maes, Gregory

doi:10.1201/b19925-4

Cited by 5 publications

(5 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The geographical distribution of A. bicolor in both Indian and Pacific basins indicates this species may also have multiple spawning sites. Understanding panmixia and the mechanisms that underpin any genetic structuring of eel populations is fundamental to the management of eel populations and the development of integrated demographic‐genetic models (Jacobsen et al, 2018; Mateo et al, 2017; Pujolar & Maes, 2016).…”

Section: Resultsmentioning

confidence: 99%

“…When different eel species share spawning locations, they have great potential for interspecies mating (Avise et al, 1990). Using genomic data, frequent occurrence of hybridization has been demonstrated for the two Atlantic Anguilla species ( A. anguilla and A. rostrata ) (Albert et al, 2006; Gagnaire et al, 2011; Pujolar & Maes, 2016; Wielgoss et al, 2014), as well as several tropical eel species (Barth et al, 2020; Schabetsberger et al, 2015). In an extensive genomic analysis of species throughout the Indo‐Pacific, hybrids for A. marmorata with the Pacific longfin eel ( A. megastoma) , Pacific shortfin eel ( A. obscura) and A. interioris , as well as A. megastoma with A. obscura were found.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Important questions to progress science and sustainable management of anguillid eels

et al. 2021

View full text Add to dashboard Cite

Anguillid eels are found globally in fresh, transitional and saline waters and have played an important role in human life for centuries. The population status of several species is now of significant concern. The threats to populations include direct exploitation at different life stages, blockages to migratory routes by dams and other structures, changes in river basin management that impact habitat carrying capacity and suitability, pollution, climate change, diseases and parasites. While much has been done to understand eel biology and ecology, a major challenge is to identify the key research and management questions so that effective and targeted studies can be designed to inform conservation, management and policy. We gathered 30 experts in the field of eel biology and management to review the current state of knowledge for anguillid eel species and to identify the main topics for research. The identified research topics fell into three themes: (a) Lifecycle and Biology; (b) Impacts and (c) Management. Although tropical anguillid eels are by far the least well understood, significant knowledge gaps exist for all species. Considerable progress has been made in the last 20 years, but the status of many species remains of great concern, particularly for northern temperate species. Without improved engagement and coordination at the regional, national and international level, the situation is unlikely to improve. Further, adaptive management mechanisms to respond to developments in science, policy and our knowledge of potential threats are required to ensure the future of these important and enigmatic species.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Important questions to progress science and sustainable management of anguillid eels

et al. 2021

View full text Add to dashboard Cite

show abstract

“…In these layers of the STUW, ripe eels may have to actively search for odor trails of individual conspecifics to find mates by following smell wafted down by the currents (Sillar et al 2016). Some tropical eels seem to spawn throughout the year (Aoyama et al 2003, Arai & Abdul Kadir 2017, and the numbers of spawners aggregating at one time may be small compared to temperate eels (estimated to be <500 spawners per spawning event; Pujolar & Maes 2016). Finding suitable mates in the vast ocean may require a risky and strenuous prolongation of the eels' spawning migration when they are nearing or have reached maturity.…”

Section: Discussionmentioning

confidence: 99%

Tracking the marine migration routes of South Pacific silver eels

Chang

Dall’Olmo

Schabetsberger

2020

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

It is still a mystery how catadromous eels find their way through the seemingly featureless open ocean to their spawning areas. Three catadromous Pacific eels (2 Anguilla marmorata, 1 A. megastoma) from the Archipelago of Vanuatu were tagged with pop-up satellite archival transmitters, and their migration tracks towards their presumed spawning area approximately 870 km northeast of the point of release were reconstructed in order to evaluate their movements in relation to oceanographic conditions. We used the timing of diel vertical migrations to derive the eels’ positions. The 2 A. marmorata exhibited steep-angled turns resulting in a zig-zag migration path along the east-west axis, while the A. megastoma took a relatively straight course towards the presumed spawning area. They migrated with a speed over ground of 21-23 km d-1. In this region, the eastward flow of the South Equatorial Counter Current (SECC, ~5°-10°S) separates the westward flowing South Equatorial Current (SEC; ~0°-5°S and 10°-18°S) into 2 branches. During shallower nighttime migration depths around 150 m, eels crossed a variable flow field through the southern branch of the westward SEC with westward propagating mesoscale eddies and the eastward SECC, but stayed south of the stronger northern branch of the SEC, possibly increasing retention time of larvae within this area. The eels headed towards a tongue of high-salinity Subtropical Underwater (STUW). The eels did not move beyond a salinity front of 35.9-36.0 at a depth of 100-200 m, which may have provided cues for orientation towards the spawning area.

show abstract

“…Moreover, spawning is temporally and spatially overlapping between multiple species, which therefore are expected to have great potential for interspecies mating (Avise et al 1990; Schabetsberger et al 2015). Frequent occurrence of hybridization has in fact been demonstrated with genomic data for the two Atlantic Anguilla species ( A. anguilla and A. rostrata ), with a particularly high proportion of hybrids in Iceland (Albert et al 2006; Gagnaire et al, 2012; Wielgoss et al, 2014; Pujolar and Maes, 2016). However, while these Atlantic species have so far received most of the scientific attention, the greatest concentration of Anguilla species is present in the tropical Indo-Pacific, where 11 species occur and may partially spawn at the same locations (Kuroki et al, 2012; Arai, 2016).…”

Section: Introductionmentioning

confidence: 89%

“…A particularly promising system for hybridization research are catadromous freshwater eels of the genus Anguilla , one of the most species-rich genera of eels with high economic value (Nelson et al, 2016). These fishes are renowned for their unique population biology, whereby all individuals of a given species reproduce panmictically in one or only few oceanic spawning areas (Jacobsen et al, 2014; Pujolar and Maes, 2016). Moreover, spawning is temporally and spatially overlapping between multiple species, which therefore are expected to have great potential for interspecies mating (Avise et al 1990; Schabetsberger et al 2015).…”

Section: Introductionmentioning

confidence: 99%

Stable Species Boundaries Despite Ten Million Years of Hybridization in Tropical Eels

Barth

Gubili²,

Matschiner

et al. 2019

Preprint

View full text Add to dashboard Cite

1Genomic evidence is increasingly underpinning that hybridization between taxa is commonplace, 2 challenging our views on the mechanisms that maintain their boundaries. Here, we focus on seven 3 catadromous eel species (genus Anguilla), and use genome-wide sequence data from more than 450 4 individuals sampled across the tropical Indo-Pacific, morphological information, and three newly 5 assembled draft genomes to compare contemporary patterns of hybridization with signatures of 6 past gene flow across a time-calibrated phylogeny. We show that the seven species have remained 7 distinct entities for up to 10 million years, despite a dynamic scenario of incomplete isolation 8 whereby the current frequencies of hybridization across species pairs (over 5% of all individuals 9 were either F1 hybrids or backcrosses) contrast remarkably with patterns of past introgression. 10Based on near-complete asymmetry in the directionality of hybridization and decreasing frequencies 11 of later-generation hybrids, we identify cytonuclear incompatibilities and hybrid breakdown as two 12 powerful mechanisms that can support species cohesion even when hybridization has been pervasive 13 throughout the evolutionary history of entire clades. 14 Introduction 17The turn of the century has witnessed a paradigm shift in how we view the role of hybridization 18 for building up biological diversity. While hybridization was previously assumed to be spatially 19 restricted and confined to a small number of taxa, it became gradually recognized that incomplete 20 isolation of genomes is widespread across eukaryotes, with varied effects on adaptation and speci-21 ation (Mallet, 2005(Mallet, , 2007 Abbott et al., 2013; Taylor and Larson, 2019). More recently, this view 22 has been further fuelled by technical and analytical advances which enable the quantification of past 23 introgression, the genetic exchange through hybridization, across entire clades, revealing that it is 24 often the most rapidly radiating clades that experienced high frequencies of gene exchange (Meier 25 et al., 2017; Lamichhaney et al., 2018; Kozak et al., 2018; Edelman et al., 2018). This seemingly 26 paradoxical association between introgression and rapid species proliferation underlies a key ques-27 tion in evolutionary biology: How can species in diversifying clades be accessible for introgression 28 but nevertheless solidify their species boundaries? To answer this question, insights are required 29 into the mechanisms that gradually reduce the degree to which hybridization generates introgres-30 sion; however, these mechanisms are still poorly understood because contemporary hybridization 31 and past introgression have so far not been jointly studied and compared across multiple pairs of 32 animal species with different divergence times within a single clade.33 Teleost fish provide well-established model systems to reveal processes of diversification, includ-34 ing the impact of hybridization on speciation (e.g., Malinsky et al., 2018a; Hench et al. 2019).35 A partic...

show abstract

Overview and Current Trends in Studies on the Evolution and Phylogeny of Anguilla

Cited by 5 publications

References 48 publications

Important questions to progress science and sustainable management of anguillid eels

Important questions to progress science and sustainable management of anguillid eels

Tracking the marine migration routes of South Pacific silver eels

Stable Species Boundaries Despite Ten Million Years of Hybridization in Tropical Eels

Contact Info

Product

Resources

About