Early life history of tropical freshwater eels (Anguilla spp.) recruiting to Viti Levu, Fiji Islands, in the western South Pacific

2020 ◽  
Vol 71 (4) ◽  
pp. 452 ◽  
Author(s):  
C. A. Hewavitharane ◽  
T. D. Pickering ◽  
C. Rico ◽  
N. Mochioka

Abstract. The oceanic early life histories of three species of tropical anguillid glass eels, namely Anguilla marmorata, Anguilla megastoma and Anguilla obscura, recruiting to Viti Levu, Fiji Islands, in the western South Pacific, were studied using otolith microstructures of 94 individuals. A. megastoma had the shortest leptocephalus duration, age at recruitment and metamorphosis stage (mean±s.d. 104.7±7.2, 141.3±8.7 and 36.6±8.5 days respectively), followed by A. marmorata (September–October recruitment peak: 113.0±11.9, 115.1±8.3 and 39.2±11.1 days respectively; April recruitment peak: 152.2±13.5, 154.0±12.5 and 38.9±10.1 days respectively) and A. obscura (118.0±10.2, 168.4±16.5 and 49.6±12.5 days respectively). A. obscura also had the shortest oceanic glass eel duration of (12.2±3.4 days), followed by both peaks of A. marmorata (23.3±3.2 and 20.2±3.3 days) and A. megastoma (20.7±6.7 days). Otolith increment rates during the leptocephalus stage did not differ significantly among the three species, but there were significant differences between the leptocephalus duration and metamorphosis stage of A. megastoma compared with A. marmorata and A. obscura, as well as in the oceanic glass eel duration of A. obscura compared with A. marmorata and A. megastoma. There were also significant differences in the age at recruitment among all three species. Back-calculated hatch dates suggest separate peak seasonal spawning periods for each of the three species.


<em>Abstract.</em>—The goal of this study was to determine if the vertical distribution of larval delta smelt <em>Hypomesus transpacificus </em>and striped bass <em>Morone saxatilis </em>was affected by tidal stage and diel period. Delta smelt and striped bass have similar early life histories in that their larvae drift downstream from freshwater spawning habitats to brackish water rearing habitats. Little is known on whether the larvae undergo a vertical migration as they move downstream. Conical plankton nets were used to collect larval fishes from the surface, middle, and bottom sections of the main channels of the Sacramento and San Joaquin rivers. Samples were collected over six paired day–night cruises. Approximately 45,000 fish were collected; 82% were striped bass and 2% were delta smelt. More delta smelt were caught at night than during the day, and more at middle depth than surface or bottom. Very few striped bass were found at surface during day; most were caught at middle depth. Both species were fairly dispersed throughout the water column at night. Although striped bass larvae appear to undergo a small surface to middepth migration, this study indicates that larval delta smelt and striped bass do not undergo a mass diel or tidal vertical migration as they drift down the Sacramento and San Joaquin rivers.



2015 ◽  
Vol 4 (3) ◽  
pp. 261-274
Author(s):  
Luke D. Gardner ◽  
Scott F. Cummins ◽  
David Mills ◽  
David Leavesley ◽  
Abigail Elizur


2017 ◽  
Vol 36 (2) ◽  
pp. 338-350 ◽  
Author(s):  
John M. McLeod ◽  
Howard L. Jelks ◽  
Sandra Pursifull ◽  
Nathan A. Johnson


Crustaceana ◽  
1994 ◽  
Vol 66 (3) ◽  
pp. 271-294 ◽  
Author(s):  
Bruce F. Phillips ◽  
John D. Booth


2014 ◽  
Vol 172 (1) ◽  
pp. 107-118 ◽  
Author(s):  
Crystal L Ruble ◽  
Patrick L Rakes ◽  
John R Shute ◽  
Stuart A Welsh




2015 ◽  
Vol 41 (2) ◽  
pp. 436-447 ◽  
Author(s):  
Michael J. Weber ◽  
Blake C. Ruebush ◽  
Sara M. Creque ◽  
Rebecca A. Redman ◽  
Sergiusz J. Czesny ◽  
...  


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