Diversity of early life-history traits in freshwater eels and the evolution of their oceanic migrations

Early life-history traits of all 19 anguillid eel species and subspecies were examined to help understand the evolutionary processes of their oceanic migrations in comparison with their migration distances and the geography of their species ranges. Tropical species were found to have fewer myomeres, greater body depths, higher growth rates, shorter larval durations, and smaller maximum larval sizes than temperate species. The relationships among larval characteristics such as growth rate, age at metamorphosis, and maximum larval size differed among tropical and temperate species and corresponded with the maximum latitudes of their species ranges. Temperate eel leptocephali with slow growth and large maximum size with slender bodies appear to be specialized for long migrations and dispersal over a wide range of distances to higher latitudes, while having flexible sizes of metamorphosis and recruitment. Tropical species with faster growth metamorphose earlier at a relatively fixed size, which would facilitate larval retention near their species ranges at low latitudes. Changes in the early life-history traits of tropical eels appear to have occurred during the evolution of longer migrations as they entered temperate regions.

Download Full-text

Prey tell: what quillback rockfish early life history traits reveal about their survival in encounters with juvenile coho salmon

Marine Ecology Progress Series ◽

10.3354/meps13300 ◽

2020 ◽

Vol 650 ◽

pp. 7-18 ◽

Cited By ~ 1

Author(s):

HW Fennie ◽

S Sponaugle ◽

EA Daly ◽

RD Brodeur

Keyword(s):

Life History ◽

Early Life ◽

Life History Traits ◽

Direct Evidence ◽

Coho Salmon ◽

Larval Fish ◽

Early Life History ◽

In The Wild ◽

Otolith Microstructure Analysis ◽

Pelagic Juvenile

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.

Download Full-text

Genetic architecture of early life history traits for channel catfish, Ictalurus punctatus ♀ × blue catfish, I. furcatus ♂ hybrid production

Aquaculture ◽

10.1016/j.aquaculture.2019.734436 ◽

2020 ◽

Vol 514 ◽

pp. 734436 ◽

Cited By ~ 1

Author(s):

Jaelen N. Myers ◽

Nagaraj G. Chatakondi ◽

Rex A. Dunham ◽

Ian A.E. Butts

Keyword(s):

Life History ◽

Ictalurus Punctatus ◽

Channel Catfish ◽

Early Life ◽

Genetic Architecture ◽

Life History Traits ◽

Early Life History ◽

Hybrid Production

Download Full-text

Significance of Egg and Larval Size to Recruitment Variability of Temperate Marine Fish

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f91-215 ◽

1991 ◽

Vol 48 (10) ◽

pp. 1820-1828 ◽

Cited By ~ 82

Author(s):

Pierre Pepin ◽

Ransom A. Myers

Keyword(s):

Life History ◽

Marine Fish ◽

Early Life ◽

Univariate Analysis ◽

Early Life History ◽

Fish Populations ◽

Larval Size ◽

Larval Phase ◽

Life History Stages ◽

Recruitment Variability

Recruitment variability is commonly associated with fluctuations in abundance of marine fish populations. Previous studies have focussed on stock-specific correlative or mechanistic models or on comparisons of recruitment variations of several stocks or species. The purpose of this study is to determine whether recruitment variability of commercial marine fish populations is associated with either size or the duration of early life history stages. The analysis was performed with data from 86 stocks representing 21 species of commercial marine fish. Univariate analysis shows that neither egg size nor the length at hatch is significantly correlated with recruitment variability. The change in length during the larval phase, which is representative of the duration of the stage, is significantly positively correlated with recruitment variability. Multivariate analysis shows that recruitment variability increases with increasing length at metamorphosis but that recruitment variability is poorly associated with length at hatch. The degree of serial correlation is related to the relative duration of egg and larval stages. The results clearly indicate that recruitment variability is linked to characteristics of early life history stages.

Download Full-text