Species composition, abundance and seasonal recruitment patterns of freshwater eels (Anguilla spp.) to Viti Levu, Fiji Islands, in the western South Pacific

Hewavitharane, Chinthaka; Pickering, T.; Ciro, R.; Mochioka, Noritaka

doi:10.1071/mf18105

Cited by 13 publications

(7 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The back calculated hatching data also provided useful information about when these eels may spawn. Combining the results of both present and previous studies estimated from leptocephali (Kuroki et al, 2008) and glass eels (Shiao et al, 2001(Shiao et al, , 2002Helme et al, 2018;Hewavitharane et al, 2018Hewavitharane et al, , 2019, the spawning of each species appears to occur over a wide range of months. Hatching date estimates of A. marmorata from the various studies occurred in almost all months of the year, and almost to the same extent for A. australis and A. reinhardtii (Fig.…”

Section: Possible Spawning Areas Of Three Anguillid Eel Speciessupporting

confidence: 82%

“…Two A. megastoma leptocephali (37.7 and 46.8 mm) caught at about 10°S to the northwest of Fiji were too large to provide any spawning location information. The glass eels of A. megastoma were much less abundant in Fiji (Hewavitharane et al, 2018). These tropical species having some glass eel recruitment during at least two periods of year or throughout most of the year (e.g., Sugeha et al, 2001;Hewavitharane et al, 2018) is different than the life-histories of temperate eel species that have single recruitment seasons.…”

Section: Larval Distribution Of Other Anguillid Eel Speciesmentioning

confidence: 99%

“…This 37 days old larva could have been transported a considerable period by the SEC or eddies. Anguilla obscura is often the most abundant species that recruits to a small river area along the southern coast of the main island of Fiji, taking 141-204 days until recruitment there, which was somewhat longer than A. megastoma (126-163 days) and A. marmorata (124-183 days) that also recruited there (Hewavitharane et al, 2018(Hewavitharane et al, , 2019. Two A. megastoma leptocephali (37.7 and 46.8 mm) caught at about 10°S to the northwest of Fiji were too large to provide any spawning location information.…”

Section: Larval Distribution Of Other Anguillid Eel Speciesmentioning

confidence: 99%

See 2 more Smart Citations

Distribution of anguillid leptocephali and possible spawning areas in the South Pacific Ocean

Kuroki

Miller

Feunteun

et al. 2020

Progress in Oceanography

View full text Add to dashboard Cite

Seven South Pacific anguillid eel species live from New Guinea to French Polynesia, but their spawning areas and life histories are mostly unknown despite previous sampling surveys. A July-October 2016 research cruise was conducted to study the spawning areas and times, and larval distributions of South Pacific anguillid eels, which included a short 155°E station-line northeast of New Guinea and five long transects (5-25°S, 160°E-140°W) crossing the South Equatorial (SEC) and other currents. This survey collected nearly 4000 anguilliform leptocephali at 179 stations using an Isaacs-Kidd Midwater Trawl accompanied by 104 CTD casts. Based on morphometric observations and DNA sequencing, 74 anguillid leptocephali were collected, which in the southern areas included 29 larvae of six species: Anguilla bicolor pacifica, A. marmorata, A. australis, A. reinhardtii, A. megastoma, and A. obscura (all anguillid species of the region were caught except A. dieffenbachii). Small A. australis (9.0-16.8 mm) and A. reinhardtii (12.4, 12.5 mm) leptocephali were collected south of the Solomon Islands, other A. australis (10.8-12.0 mm) larvae were caught northwest of Fiji along with an A. obscura (20.0 mm) larva, and an A. marmorata (7.8 mm) larva was collected near Samoa. Considering collection sites, larval ages from otolith analysis, and westward SEC drift, multiple spawning locations occurred from south of the Solomon Islands and the Fiji area (16-20 days old larvae) to near Samoa (19 days old larva) during June and July in areas where high-salinity Subtropical Underwater (STUW, ~150 m depth) and the warm, low-salinity surface Fresh Pool were present. Five long hydrographic sections showed the strong Fresh Pool in the west and the STUW formation area in the east.

show abstract

Section: Possible Spawning Areas Of Three Anguillid Eel Speciessupporting

confidence: 82%

Section: Larval Distribution Of Other Anguillid Eel Speciesmentioning

confidence: 99%

Section: Larval Distribution Of Other Anguillid Eel Speciesmentioning

confidence: 99%

See 1 more Smart Citation

Distribution of anguillid leptocephali and possible spawning areas in the South Pacific Ocean

Kuroki

Miller

Feunteun

et al. 2020

Progress in Oceanography

View full text Add to dashboard Cite

show abstract

“…The mechanisms that underpin the recruitment of glass eels to continental habitats are not well understood, particularly in tropical anguillid species (Cresci, 2020; Helme et al, 2018; Hewavitharane et al, 2018), but are known to include physiological as well as environmental drivers that can act over timescales of days to weeks (Edeline et al, 2009; review by Harrison et al, 2014). Glass eel and leptocephalus mortality, be it natural or due to anthropogenic activities, is particularly poorly understood and in need of further research to enable sustainable management (e.g.…”

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

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

“…The spawning occurred through the whole year in several tropical eel species ( Arai et al., 2001 ; Shiao et al., 2002 ; Arai et al., 2016 ; Arai and Abdul Kadir, 2017a ). The year-round spawning together with constant early growth during the oceanic period throughout the year, expand the recruitment period to continental habitats throughout the entire year for tropical anguillid eels ( Beumer and Sloane, 1990 ; Arai et al., 1999b ; Sugeha et al., 2001 ; Han et al., 2012b , 2016a ; Leander et al., 2012 ; Aoyama et al., 2015 ; Hewavitharane et al., 2018 ). The continuous spawning migration may stimulate breeding with different cohorts (year classes) or divergent habitats within the population.…”

Section: Evolution Of Oceanic Migrationmentioning

confidence: 99%

Ecology and evolution of migration in the freshwater eels of the genus Anguilla Schrank, 1798

Arai

2020

Heliyon

View full text Add to dashboard Cite

Scientists have long sought to uncover the secrets of the migration of anguillid eels, genus Anguilla . As catadromous fishes, anguillid eels spend most of their lives in freshwater until they return to their spawning grounds in the tropics, although part of the population never enters freshwater and instead resides in brackish and marine areas close to coastlines. Molecular phylogenetic research suggests that anguillid eels originated from deep-ocean midwater marine anguilliform species and that tropical eels originating from the Indo-Pacific region are the most basal species of anguillid eels. Anguillid eels left the tropical ocean to colonize temperate areas. The yearly spawning of tropical species and constant larval growth throughout the year extend to periods of recruitment in continental habitats to last all year for tropical eels. Tropical eels such as A. celebesensis and A. borneensis have relatively short migrations periods of less than 100 km to their spawning grounds. Conversely, the temperate European eel A. anguilla travels the longest distances and migrates more than 5000 km across the Atlantic Ocean to spawn in the Sargasso Sea. The ancestral state of migration in the genus Anguilla may have been local, short-scale and nonseasonal spawning migration throughout the year as defined in tropical eels. With the expansion of dispersion of global oceanic migration across the world, migration scales can gradually change. Temperate anguillid eels migrate thousands of kilometres from spawning areas to coastal and inland water habitats while retaining spawning areas in tropical areas, accompanied by seasonal downstream and spawning migrations with consequences for seasonal recruitment. Recent advances and the availability of electronic tags such as pop-up satellite archival tag could reconstruct the entire spawning migration from continental growth habitats to spawning sites with detailed migration behaviours and routes. Migration ecology and mechanisms throughout the life of anguillid eels have gradually been revealed in recent decades.

show abstract

Species composition, abundance and seasonal recruitment patterns of freshwater eels (Anguilla spp.) to Viti Levu, Fiji Islands, in the western South Pacific

Cited by 13 publications

References 25 publications

Distribution of anguillid leptocephali and possible spawning areas in the South Pacific Ocean

Distribution of anguillid leptocephali and possible spawning areas in the South Pacific Ocean

Important questions to progress science and sustainable management of anguillid eels

Ecology and evolution of migration in the freshwater eels of the genus Anguilla Schrank, 1798

Contact Info

Product

Resources

About