Likely Population-Level Effects of Contaminants on a Resident Estuarine Fish Species: Comparing Gillichthys mirabilis Population Static Measurements and Vital Rates in San Francisco and Tomales Bays

Background The application of otolith-based tools to inform the management and conservation of fishes first requires taxon- and stage-specific validation. The Delta Smelt (Hypomesus transpacificus), a critically endangered estuarine fish that is endemic to the upper San Francisco Estuary (SFE), California, United States, serves as a key indicator species in the SFE; thus, understanding this species’ vital rates and population dynamics is valuable for assessing the overall health of the estuary. Otolith-based tools have been developed and applied across multiple life stages of Delta Smelt to reconstruct age structure, growth, phenology, and migration. However, key methodological assumptions have yet to be validated, thus limiting confidence in otolith-derived metrics that are important for informing major water management decisions in the SFE. Methods Using known-age cultured Delta Smelt and multiple independent otolith analysts, we examined otolith formation, otolith-somatic proportionality, aging accuracy and precision, left-right symmetry, and the effects of image magnification for larval, juvenile, and adult Delta Smelt. Results Overall, otolith size varied linearly with fish size (from 10–60 mm), explaining 99% of the variation in fish length, despite a unique slope for larvae < 10 mm. Otolith-somatic proportionality was similar among wild and cultured specimens. Aging precision among independent analysts was 98% and aging accuracy relative to known ages was 96%, with age estimates exhibiting negligible differences among left and right otoliths. Though error generally increased with age, percent error decreased from 0–30 days-post-hatch, with precision remaining relatively high (≥ 95%) thereafter. Increased magnification (400×) further improved aging accuracy for the oldest, slowest-growing individuals. Together, these results indicate that otolith-based techniques provide reliable age and growth reconstructions for larval, juvenile, and adult Delta Smelt. Such experimental assessments across multiple developmental stages are key steps toward assessing confidence in otolith-derived metrics that are often used to assess the dynamics of wild fish populations.

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Size-based, seasonal, and multidirectional movements of an estuarine fish species in a habitat mosaic

Marine Ecology Progress Series ◽

10.3354/meps10837 ◽

2014 ◽

Vol 507 ◽

pp. 263-276 ◽

Cited By ~ 19

Author(s):

AB Barbour ◽

AJ Adams ◽

K Lorenzen

Keyword(s):

Fish Species ◽

Estuarine Fish ◽

Habitat Mosaic

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214 Longitudinal Changes in Sleep Duration, Timing, Variability, and Stages during the COVID-19 Pandemic: Large-Scale Fitbit Data

SLEEP ◽

10.1093/sleep/zsab072.213 ◽

2021 ◽

Vol 44 (Supplement_2) ◽

pp. A86-A86

Author(s):

Michael Grandner ◽

Naghmeh Rezaei

Keyword(s):

New York ◽

Los Angeles ◽

San Francisco ◽

Sleep Duration ◽

Large Scale ◽

Age Groups ◽

Population Level ◽

Sleep Stages ◽

Longitudinal Changes ◽

Timing Variability

Abstract Introduction The COVID-19 pandemic has resulted in societal-level changes to sleep and other behavioral patterns. Objective, longitudinal data would allow for a greater understanding of sleep-related changes at the population level. Methods N= 163,524 deidentified active Fitbit users from 6 major US cities contributed data, representing areas particularly hard-hit by the pandemic (Chicago, Houston, Los Angeles, New York, San Francisco, and Miami). Sleep variables extracted include nightly and weekly mean sleep duration and bedtime, variability (standard deviation) of sleep duration and bedtime, and estimated arousals and sleep stages. Deviation from similar timeframes in 2019 were examined. All analyses were performed in Python. Results These data detail how sleep duration and timing changed longitudinally, stratified by age group and gender, relative to previous years’ data. Overall, 2020 represented a significant departure for all age groups and both men and women (P<0.00001). Mean sleep duration increased in nearly all groups (P<0.00001) by 5-11 minutes, compared to a mean decrease of 5-8 minutes seen over the same period in 2019. Categorically, sleep duration increased for some and decreased for others, but more extended than restricted. Sleep phase shifted later for nearly all groups (p<0.00001). Categorically, bedtime was delayed for some and advanced for others, though more delayed than advanced. Duration and bedtime variability decreased, owing largely to decreased weekday-weekend differences. WASO increased, REM% increased, and Deep% decreased. Additional analyses show stratified, longitudinal changes to sleep duration and timing mean and variability distributions by month, as well as effect sizes and correlations to other outcomes. Conclusion The pandemic was associated with increased sleep duration on average, in contrast to 2019 when sleep decreased. The increase was most profound among younger adults, especially women. The youngest adults also experienced the greatest bedtime delay, in line with extensive school-start-times and chronotype data. When given the opportunity, the difference between weekdays and weekends became smaller, with occupational implications. Sleep staging data showed that slightly extending sleep minimally impacted deep sleep but resulted in a proportional increase in REM. Wakefulness during the night also increased, suggesting increased arousal despite greater sleep duration. Support (if any) This research was supported by Fitbit, Inc.

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Preliminary assessment of surf-zone and estuarine line-fish species of the Dwesa-Cwebe Marine Protected Area, Eastern Cape, South Africa

Koedoe ◽

10.4102/koedoe.v54i1.1059 ◽

2012 ◽

Vol 54 (1) ◽

Cited By ~ 4

Author(s):

Jan A. Venter ◽

Bruce Q. Mann

Keyword(s):

South Africa ◽

Law Enforcement ◽

Fish Species ◽

Protected Area ◽

Surf Zone ◽

Marine Protected Area ◽

Fish Populations ◽

Estuarine Fish ◽

Catch Per Unit Effort ◽

Preliminary Assessment

A preliminary assessment of surf-zone and estuarine line fish was carried out in the DwesaCwebe Marine Protected Area (MPA), on the Wild Coast, South Africa. The purpose was to provide baseline data on inshore line-fish stocks in the MPA. A total of 28 species was recorded, of which 53% have a conservation status reflecting some concern and 43% are endemic to southern Africa. This highlights the value of the MPA for protection of important line-fish species. Within the MPA, localised differences were detected in species diversity, size frequency and catch per unit effort between unexploited and illegally exploited areas. These differences were more prominent in slow growing, long-lived species. It thus appears that illegal exploitation is negatively affecting fish populations within the MPA, which counteract and potentially could eliminate the benefits of fish protection typically associated with no-take MPAs. These results highlight the need for improved law enforcement and better communication with neighbouring communities to increase awareness. It is further recommended that the current no-take status of the MPA should be maintained. In addition, baseline fisheries information was collected on certain fish species that could be used to inform future conservation management of the MPA.Conservation implications: The Dwesa-Cwebe Marine Protected Area is unique and important for the conservation of key surf zone and estuarine fish species. However there is a significant risk to the fish populations due to illegal exploitation. Key interventions should include enhanced law enforcement but, more important, the creation of alternative livelihoods and long term sustainable benefits to local communities.

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The contribution of environmental factors to fish assemblages in the Río Acahuapa, a small drainage in Central America

Neotropical Ichthyology ◽

10.1590/1982-0224-20170023 ◽

2017 ◽

Vol 15 (3) ◽

Cited By ~ 1

Author(s):

Francisco S. Álvarez ◽

Wilfredo A. Matamoros ◽

Francisco A. Chicas

Keyword(s):

Fish Species ◽

Habitat Structure ◽

Fish Assemblages ◽

Species Abundance ◽

Main Channel ◽

Estuarine Fish ◽

Species Origin ◽

High Temperature Water ◽

Distribution Of Fish ◽

Temperature Water

ABSTRACT The ichthyofauna of the Río Acahuapa was analyzed sampling 17 sites that included the basin main channel and its tributaries. Fish were collected using dip-nets, seine-nets and electrofishing. Fish standard length and species abundance were recorded. Species origin and salinity tolerance criteria were used to classify fish species. Water physicochemical variables, habitat structure and sampling sites elevation were recorded. A total of 33 fish species were registered, 12.1% are primary, 45.5% are secondary and 42.4% are of marine derivation. Fish species richness declined with increase of elevation (R2=0.55, p=0.0006). Two assemblages of fishes were identified: the first one associated to sites of low elevations (19-184 masl), composed mainly of secondary and marine-estuarine fish species related with high temperature, water velocity, river width, dissolved oxygen and low sand and silt substrate cover; the second one associated to sites of middle and higher elevations (185-519 masl), composed by primary and secondary freshwater fishes related with high pH, logs and rocks substrate cover. In summary, elevation and environmental variables contributed to the composition and distribution of fish in the Río Acahuapa.

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Abstract MP38: Longitudinal Population-Level Changes In Resting Heart Rate During The COVID-19 Pandemic: Impact Of Changes In Sleep, Circadian, And Physical Activity Variables

Circulation ◽

10.1161/circ.143.suppl_1.mp38 ◽

2021 ◽

Vol 143 (Suppl_1) ◽

Author(s):

Naghmeh Rezaei ◽

Michael A Grandner

Keyword(s):

New York ◽

Heart Rate ◽

Los Angeles ◽

Health Behaviors ◽

San Francisco ◽

Sleep Duration ◽

Age Groups ◽

Population Level ◽

Sleep Stages ◽

Resting Heart Rate

Introduction: Population-level objective estimates of changes in health metrics over the course of the COVID-19 pandemic are sparse. This study evaluated change in resting heart rate (RHR) determined by optical plethysmography and relationships to changes in other lifestyle health behaviors (sleep and activity). Methods: Data were obtained from N=197,988 Fitbit users who wore their heart-rate enabled Fitbit device to sleep and had detected sleep stages at least 10 days in the month of January, the baseline period; and synced their devices at least once in the last 10 days of April. In addition, potential participants needed to reside in one of 6 target cities: Chicago, Illinois; Houston, Texas; Los Angeles, California; San Francisco, California; New York City, New York; and Miami, Florida. Users who met these criteria were randomly selected. Daily RHR, sleep duration (minutes), sleep duration variability (standard deviation), bedtime, step count, and active minutes were estimated by the device. Differences between January (before the pandemic) and April (peak of stay-at-home orders) was computed. Correlations between change in RHR and change in other variables were evaluated, stratified by age and sex. Results: For all age groups, in both men and women, mean RHR declined from January to April by about 1bpm, with the highest reductions in the youngest adults (all p<1x10 -100 ). In general, across both genders and all age groups, reductions in RHR were correlated with greater sleep duration, delaying bedtime, reduced sleep variability, and more active minutes. Steps were also associated in younger (but not older) adults. Results for ages 18-29 and >=65 are displayed in the Table. Discussion: During the COVID-19 pandemic, RHR decreased robustly but very slightly. Reductions in RHR were correlated with improvements in other health behaviors (sleep and activity). Causal relationships could not be evaluated, but future studies may explore whether even small changes in health behaviors can measurably impact population RHR.

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