Larger body size and earlier run timing increase alewife reproductive success in a whole lake experiment

Marjadi, Meghna N.; Roy, Allison H.; Jordaan, Adrian; Gahagan, Benjamin I.; Armstrong, Michael P.; Whiteley, Andrew R.

doi:10.1139/cjfas-2017-0451

Cited by 17 publications

(25 citation statements)

References 90 publications

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“…Since Alewives are batch spawners (Ganias et al. ; Marjadi et al., in press), repeated short‐term residencies on the spawning grounds are likely indicative of multiple spawning events. Some individuals visited the spawning grounds up to four times, consistent with oocyte histology findings (Ganias et al.…”

Section: Discussionmentioning

confidence: 99%

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A New Paradigm in Alewife Migration: Oscillations between Spawning Grounds and Estuarine Habitats

et al. 2019

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The current paradigm in Alewife Alosa pseudoharengus migrations is shifting from a single reproductive event and rapid movement in and out of freshwater to one that recognizes more nuanced movements and asynchronous batch spawning. In this study, Alewives (n = 72) were acoustically tagged in the Carmans River, Long Island, New York, a small coastal river with restored fish passage. Our objective was to examine fine-scale spatial movements in the tidal and reconnected habitats to identify spawning behavior patterns, including habitat use and spawning periodicity, that can be applied to fishway restoration and species management. Alewives that completed their spawning migration (n = 27) exhibited variability in posttagging trajectories, residency, passage rate, and behavior. The current paradigm consisting of a single upstream migration followed by a downstream migration was only seen in 26% (n = 7) of fish, while 41% (n = 11) deviated from the paradigm and made multiple reversals and numerous movements on and off the spawning grounds. Oscillations spanned from the estuary into the reconnected habitat and resulted in a proportionally large amount of time spent in the estuarine and brackish habitats. Some oscillations also consisted of multiple fishway passage events within a season. Oscillation behavior is likely a naturally occurring spawning strategy that has gone undetected. Consequently, the proportion of individuals of a population that display single versus multiple passage events could result in fishway counts that bias run size estimations and thus population assessments.

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Section: Discussionmentioning

confidence: 99%

“…), in which females could spawn at least three batches per season. Alewives have been observed to reproduce with mates from different components of the run, and multiple males contribute to each female reproductive event (Marjadi et al., in press). The spawning behaviors observed here are consistent with those observations.…”

Section: Discussionmentioning

confidence: 99%

A New Paradigm in Alewife Migration: Oscillations between Spawning Grounds and Estuarine Habitats

et al. 2019

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“…Different life history stages may have unique phenologies, while density‐dependent effects can also influence seasonal events such as the timing and duration of migration and spawning. For example, the timing of river herring and Atlantic herring movements is related to the size of individual fish, with larger fish arriving first on spawning grounds (Lambert, ; Marjadi et al, ). If the proportion of large fish in the population changed over time, this could appear as a shift in spawning phenology whether or not it was real.…”

Section: Confounding Factors For Detecting and Understanding Shifts Imentioning

confidence: 99%

It’s about time: A synthesis of changing phenology in the Gulf of Maine ecosystem

Staudinger

Mills

Stamieszkin

et al. 2019

Fisheries Oceanography

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The timing of recurring biological and seasonal environmental events is changing on a global scale relative to temperature and other climate drivers. This study considers the Gulf of Maine ecosystem, a region of high social and ecological importance in the Northwest Atlantic Ocean and synthesizes current knowledge of (a) key seasonal processes, patterns, and events; (b) direct evidence for shifts in timing; (c) implications of phenological responses for linked ecological‐human systems; and (d) potential phenology‐focused adaptation strategies and actions. Twenty studies demonstrated shifts in timing of regional marine organisms and seasonal environmental events. The most common response was earlier timing, observed in spring onset, spring and winter hydrology, zooplankton abundance, occurrence of several larval fishes, and diadromous fish migrations. Later timing was documented for fall onset, reproduction and fledging in Atlantic puffins, spring and fall phytoplankton blooms, and occurrence of additional larval fishes. Changes in event duration generally increased and were detected in zooplankton peak abundance, early life history periods of macro‐invertebrates, and lobster fishery landings. Reduced duration was observed in winter–spring ice‐affected stream flows. Two studies projected phenological changes, both finding diapause duration would decrease in zooplankton under future climate scenarios. Phenological responses were species‐specific and varied depending on the environmental driver, spatial, and temporal scales evaluated. Overall, a wide range of baseline phenology and relevant modeling studies exist, yet surprisingly few document long‐term shifts. Results reveal a need for increased emphasis on phenological shifts in the Gulf of Maine and identify opportunities for future research and consideration of phenological changes in adaptation efforts.

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“…While causes of mortality are often hard to discern, advances in molecular techniques allow for reproductive success to be assessed through genetically reconstructed pedigrees, providing a sufficient proportion of the population can be sampled (e.g. Marjadi et al , 2019). However, more evidence of the impact of genetic admixture, and the degree to which it may have positive or negative effects on threatened populations, is needed before it could be considered standard practice in species management plans.…”

Section: Introductionmentioning

confidence: 99%

Mixing genetically differentiated populations successfully boosts diversity of an endangered carnivore

McLennan

Grueber

Wise³

et al. 2020

Animal Conservation

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Biodiversity decline and genetic erosion are among the most challenging conservation issues. Genetic admixture, the mixing of two or more genetically differentiated populations, can increase genetic diversity of admixed individuals. However, genetic admixture for conservation purposes is rare due to concerns over outbreeding depression, loss of local adaptations and scepticism regarding the benefits of mixing populations. We used an introduced population of Tasmanian devils Sarcophilus harrisii descended from two genetically differentiated source populations to illustrate the benefits of genetic admixture for translocation programmes. Devils are endangered due to an infectious cancer causing 80% population declines across their range since disease emergence in 1996. Devil populations are known to be structured on an east-west cline across Tasmania. As part of their conservation management, devils were introduced to Maria Island, Tasmania in an assisted colonization in 2012 with supplementations in 2013 and 2017. Of the released individuals (N = 34), 23 were western (13M; 10F), four were eastern (4F) and seven were of mixed origin (2M; 5F). The genetic composition of devils born on Maria Island (N = 185) was examined using 927 single nucleotide polymorphism loci. Using a reconstructed pedigree for each individual, we examined the proportion of founding origin (east, west or mixed) and used Shannon's Diversity Index to quantify the evenness of founder origin. Individuals with mixed origins (N = 102) had higher genetic diversity than purebred individuals (N = 83), and increased evenness of founder origin was positively correlated with genetic diversity. Increased genetic diversity had no influence on reproductive success. For a genetically depauperate species, mixing individuals descended from differentiated populations, resulted in increased diversity in subsequent generations. This finding permits conservation managers to select individuals for translocation that produce offspring with higher genetic diversity, creating high-diversity source populations that can be used when augmenting other declining wild populations.

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Larger body size and earlier run timing increase alewife reproductive success in a whole lake experiment

Cited by 17 publications

References 90 publications

A New Paradigm in Alewife Migration: Oscillations between Spawning Grounds and Estuarine Habitats

A New Paradigm in Alewife Migration: Oscillations between Spawning Grounds and Estuarine Habitats

It’s about time: A synthesis of changing phenology in the Gulf of Maine ecosystem

Mixing genetically differentiated populations successfully boosts diversity of an endangered carnivore

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