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USGS2016

Increased temperatures combined with lowered salinities differentially impact oyster size class growth and mortality

Changes in the timing and interaction of seasonal high temperatures and low salinities as predicted by climate change models could dramatically alter oyster population dynamics. Little is known explicitly about how low salinity and high temperature combinations affect spat (<25mm), seed (25–75mm), andmarket (>75mm) oyster growth and mortality. Using field and laboratory studies, this project quantified the combined effects of extremely low salinities (<5) and high temperatures (>30°C) on growth and survival of spat, seed, andmarket-sized oysters. In 2012 and 2013, hatchery-produced oysters were placed in open and closed cages at three sites in Breton Sound, LA, along a salinity gradient that typically ranged from 5 to 20. Growth and mortality were recorded monthly. Regardless of size class, oysters at the lowest salinity site (annualmean = 4.8) experienced significantly highermortality and lower growth than oysters located in higher salinity sites (annual means = 11.1 and 13.0, respectively); furthermore, all oysters in open cages at the two higher salinity sites experienced higher mortality than in closed cages, likely due to predation. To explicitly examine oyster responses to extreme low salinity and high temperature combinations, a series of laboratory studies were conducted. Oysters were placed in 18 tanks in a fully crossed temperature (25°C, 32°C) by salinity (1, 5, and 15) study with three replicates, and repeated at least twice for each oyster size class. Regardless of temperature, seed and market oysters held in low salinity tanks (salinity 1) experienced 100% mortality within 7 days. In contrast, at salinity 5, temperature significantly affected mortality; oysters in all size classes experienced greater than 50%mortality at 32°C and less than 40%mortality at 25°C. At the highest salinity tested (15), only market-sized oysters held at 32°C experienced significant mortality (>60%). These studies demonstrate that high water temperatures (>30°C) and low salinities (<5) negatively impact oyster growth and survival differentially and that high temperatures alone may negatively impact market-sized oysters. It is critical to understand the potential impacts of climate and anthropogenic changes on oyster resources to better adapt and manage for long-term sustainability.

Louisiana↗

USGS2010

Effects of High-Flow Experiments from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lees Ferry Reach of the Colorado River

High-flow experiments (HFEs) from Glen Canyon Dam are primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River as it flows through Grand Canyon National Park, Arizona. These experimental flows also have the potential to affect the rainbow trout (Oncorhynchus mykiss) population in the Lees Ferry tailwater reach immediately below the dam, which supports a highly valued recreational fishery and likely influences the abundance of rainbow trout in Grand Canyon. Understanding how flow regimes affect the survival and growth of juvenile rainbow trout is critical to interpreting trends in adult abundance. This study reports on the effects of HFEs in 2004 and 2008 on early life stages of rainbow trout in the Lees Ferry reach on the basis of monthly sampling of redds (egg nests) and the abundance of the age-0 trout (fertilization to about 1 to 2 months from emergence) and their growth during a 7-year period between 2003 and 2009. Multiple lines of evidence indicate that the March 2008 HFE resulted in a large increase in early survival rates of age-0 trout because of an improvement in habitat conditions. A stock-recruitment analysis demonstrated that age-0 abundance in July 2008 was more than fourfold higher than expected, given the number of viable eggs that produced these fish. A hatch-date analysis showed that early survival rates were much higher for cohorts that hatched about 1 month after the 2008 HFE (about April 15, 2008) relative to those fish that hatched before this date. These cohorts, fertilized after the 2008 HFE, would have emerged into a benthic invertebrate community that had recovered, and was possibly enhanced by, the HFE. Interannual differences in growth of age-0 trout, determined on the basis of otolith microstructure, support this hypothesis. Growth rates in the summer and fall of 2008 (0.44 mm/day) were virtually the same as in 2006 (0.46 mm/day), the highest recorded during 6 years, even though abundance was eightfold greater in 2008. We speculate that the 60-hour-long 2008 HFE (with peak magnitude about twice that of the annual peak flow during the previous 4 years) increased interstitial spaces in the gravel bed substrate and food availability or quality, leading to higher early survival of recently emerged trout and better growth of these fish through summer and fall. Abundance in 2009 was more than twofold higher than expected, given the estimated number of viable eggs deposited in that year, perhaps indicating that the effect of the 2008 HFE on early life stages was somewhat persistent. In a 3-week interval that spanned the November 2004 HFE, abundance of age-0 trout that were approximately 7 months old from hatch experienced about a threefold decline, compared to the approximately twofold decrease observed between November and December 2008. Abundance of age-0 trout that were approximately 10 months old from hatch was very similar across sampling trips that spanned the March 2008 HFE. It is uncertain whether the decline in abundance after the November 2004 HFE was the result of higher flow-induced mortality or higher flow-induced downstream dispersal. A focused monitoring effort in Marble Canyon (the reach immediately downstream of the Lees Ferry tailwater) before and after future HFEs is recommended to resolve this uncertainty. Relatively detailed monitoring of early life stages-such as the program described in this study-is essential to establish linkages between Glen Canyon Dam operations, or possibly other factors, and trends in the abundance of important nonnative and native fish populations living downstream within Grand Canyon National Park.

Open-File Report↗

USGS2014

Evaluation of coral pathogen growth rates after exposure to atmospheric African dust samples

Laboratory experiments were conducted to assess if exposure to atmospheric African dust stimulates or inhibits the growth of four putative bacterial coral pathogens. Atmospheric dust was collected from a dust-source region (Mali, West Africa) and from Saharan Air Layer masses over downwind sites in the Caribbean [Trinidad and Tobago and St. Croix, U.S. Virgin Islands (USVI)]. Extracts of dust samples were used to dose laboratory-grown cultures of four putative coral pathogens: Aurantimonas coralicida (white plague type II), Serratia marcescens (white pox), Vibrio coralliilyticus , and V. shiloi (bacteria-induced bleaching). Growth of A. coralicida and V. shiloi was slightly stimulated by dust extracts from Mali and USVI, respectively, but unaffected by extracts from the other dust sources. Lag time to the start of log-growth phase was significantly shortened for A. coralicida when dosed with dust extracts from Mali and USVI. Growth of S. marcescens and V. coralliilyticus was neither stimulated nor inhibited by any of the dust extracts. This study demonstrates that constituents from atmospheric dust can alter growth of recognized coral disease pathogens under laboratory conditions.

Caribbean Sea↗

USGS2018

Juvenile Lost River and shortnose sucker year class strength, survival, and growth in Upper Klamath Lake, Oregon, and Clear Lake Reservoir, California—2016 Monitoring Report

Executive Summary The largest populations of federally endangered Lost River ( Deltistes luxatus) and shortnose suckers ( Chasmistes brevirostris ) exist in Upper Klamath Lake, Oregon, and Clear Lake Reservoir, California. Upper Klamath Lake populations are decreasing because adult mortality, which is relatively low, is not being balanced by recruitment of young adult suckers into known spawning aggregations. Most Upper Klamath Lake juvenile sucker mortality appears to occur within the first year of life. Annual production of juvenile suckers in Clear Lake Reservoir appears to be highly variable and may not occur at all in very dry years. However, juvenile sucker survival is much higher in Clear Lake, with non-trivial numbers of suckers surviving to join spawning aggregations. Long-term monitoring of juvenile sucker populations is needed to (1) determine if there are annual and species-specific differences in production, survival, and growth, (2) to identify the season (summer or winter) in which most mortality occurs, and (3) to help identify potential causes of high juvenile sucker mortality, particularly in Upper Klamath Lake. We initiated an annual juvenile sucker monitoring program in 2015 to track cohorts in 3 months (June, August, and September) annually in Upper Klamath Lake and Clear Lake Reservoir. We tracked annual variability in age-0 sucker apparent production, juvenile sucker apparent survival, and apparent growth. Using genetic markers, we were able to classify suckers as one of three taxa: shortnose or Klamath largescale suckers, Lost River, or suckers with genetic markers of both species (Intermediate Prob[LRS]). Using catch data, we generated taxa-specific indices of year class strength, August–September apparent survival, and overwinter apparent survival. We also examined prevalence and severity of afflictions such as parasites, wounds, and deformities. Indices of year class strength in Upper Klamath Lake were similar for shortnose suckers in 2015 and 2016, but about twice as high for Lost River suckers and suckers having intermediate Prob[LRS] in 2016 than in 2015. Indices of apparent August–September survival were lower in 2016 (0.41) than in 2015 (1.07) for shortnose suckers and suckers identified as having intermediate Prob [LRS] (0.14 in 2016 and 1.69 in 2015). Indices of apparent August—September survival were similar in 2016 (0.16) and 2015 (0.07) for Lost River suckers. Indices of apparent survival were lower for age-0 Lost River suckers than age-0 shortnose suckers in both years. Although samples sizes are small, a declining trend in the ratio of Lost River to shortnose suckers from 28/23 (1.22) as age-0 fish in September of 2015 to 1/9 (0.11) as age-1 fish in June of 2016 is consistent with higher over winter apparent mortality for Lost River suckers than shortnose suckers in Upper Klamath Lake. Shortnose sucker year class strength was greater in years with high Willow Creek inflows and Clear Lake surface elevation during the spawning season, indicating that access to spawning habitat was an important contributing factor. In previous sampling, age-0 sucker catch per unit effort (CPUE) was relatively high in 2011 and 2012, moderately high in 2013, and zero in 2014 and 2015. The 2011 and 2012 year classes continued to be detected, but the 2013 year class went undetected for the first time in 2016. The 2014 year class continued to be undetected in 2016. Three suckers with one annulus each on fin rays were captured in Clear Lake in 2016. Although these fish are potential representatives of the 2015 year class, they were small for their age, indicating they may have hatched in 2016. Age-0 shortnose and Lost River suckers were captured in Clear Lake in 2016, indicating new cohorts of both taxa were produced. Moderate to abundant year classes were produced in 2011, 2012, and 2016 when lake surface elevation greater than 1,378.9 m (4,524 ft) during the February–June spawning season. Also in 2011 and 2016, rapid increases in lake-surface elevation indicated potentially high Willow Creek inflows. A somewhat less abundant year class produced in 2012 than in 2011 and 2016 was associated with lower spawning season inflows. The apparently smaller 2013 year class was formed when Willow Creek inflows were apparently low and lake surface never exceeded 1,379.2 m (4,524.9 ft). In 2014 and 2015, when year-classes were small or not detected, the Clear Lake surface elevations were at or below 1,378.2 m (4,522 ft), and there was very little spring time Willow Creek inflow. Age-0 shortnose sucker CPUE in Clear Lake was correlated with seasonal decreases in water volumes in 2016 and could not be used to create indices of August–September survival. Age-0 shortnose sucker catch rates in Clear Lake Reservoir were about seven times less in August than in September. Meanwhile, the water volume in Clear Lake Reservoir declined by about 36 percent between these two sampling periods. Higher September catch rates may have resulted from additional age-0 suckers entering the lake from the river, a concentrating effect of declining water volumes, or both. Differences in August standard length, apparent growth rates, and the prevalence of abnormalities were consistent with healthier age-0 suckers in Clear Lake Reservoir than in Upper Klamath Lake. Age-0 suckers were larger in August in Clear Lake Reservoir than in Upper Klamath Lake, which may be due to an earlier hatch date, faster growth, or both in Clear Lake Reservoir. Sample sizes were only large enough to compare growth rates of age-0 shortnose suckers from Upper Klamath Lake in 2015 to Clear Lake Reservoir in 2016. Age-0 shortnose suckers grew more between August and September in Clear Lake Reservoir in 2016 than in Upper Klamath Lake in 2015. Petechial hemorrhages of the skin on age-0 suckers were more prevalent in Upper Klamath Lake than in Clear Lake Reservoir in 2016. Deformed opercula, black-spot forming parasites, and infections presumed to be Columnaris sp. were observed on less than 12 percent of suckers from Upper Klamath Lake but were not observed on suckers from Clear Lake Reservoir in 2016.

California, Oregon↗

USGS2003

Interactive effects of redox intensity and phosphate availability on growth and nutrient relations of Cladium jamaicense (Cyperaceae)

Expansion of Typha domingensis into areas previously dominated by Cladium jamaicense in the Florida Everglades has been linked to anthropogenic phosphorus (P) enrichment and increased hydroperiod. The principal stress factor for plants in flooded soils is biochemical reduction, the intensity of which is measured as redox potential (Eh). The objective of this study was to assess the growth response of C. jamaicense to Eh (−150, +150, and +600 mV) and P availability (10, 80, and 500 μg P/L). Plants were grown hydroponically in a factorial experiment using titanium (Ti 3+ ) citrate as an Eh buffer. Treatment effects on growth, biomass partitioning, and tissue nutrients were recorded. Growth approximately doubled in response to a 50‐fold increase in P availability. Low redox significantly reduced growth and tissue P concentration. While plant P concentrations increased 20‐fold between the 10 and 500 μg P/L treatments, P concentrations were 50–100% higher at +600 mV than at −150 mV within each phosphate level. At high Eh, C. jamaicense appears well adapted to low nutrient environments because of its low P requirement and high retention of acquired P. However, at low Eh the ability to acquire or conserve acquired P decreases and as a consequence, higher phosphate levels are required to sustain growth. Findings of this study indicate that young C. jamaicense exhibits low tolerance to strongly reducing conditions when phosphate is scarce.

Florida↗

USGS2003

An empirical model of the phytoplankton chlorophyll : carbon ratio-the conversion factor between productivity and growth rate

We present an empirical model that describes the ratio of phytoplankton chlorophyll a to carbon, Chl: C, as a function of temperature, daily irradiance, and nutrient-limited growth rate. Our model is based on 219 published measurements of algal cultures exposed to light-limited or nutrient-limited growth conditions. We illustrate an approach for using this estimator of Chl: C to calculate phytoplankton population growth rate from measured primary productivity. This adaptive Chl: C model gives rise to interactive light-nutrient effects in which growth efficiency increases with nutrient availability under low-light conditions. One implication of this interaction is the enhancement of phytoplankton growth efficiency, in addition to enhancement of biomass yield, as a response to eutrophication.

Limnology and Oceanography↗

USGS2026

Geolocator devices did not affect chick growth or adult return rates in Wedge-tailed Shearwaters (Ardenna pacifica) despite interannual variation in chick development

Although biologging has transformed seabird ecology, bird-borne devices could alter the behaviors being studied, including parental care. We tested for effects of leg-mounted light-level geolocators (< 1% of body mass) on chick growth and adult return rates in Wedge-tailed Shearwaters (‘ua‘u kani, Ardenna pacifica ) breeding on O‘ahu, Hawai‘i during two consecutive breeding seasons that coincided with contrasting El Niño Southern Oscillation (ENSO) years. Accounting for hatching phenology, we compared three responses of two tagging groups (tagged and non-tagged controls): (1) chick growth rates (mass, wing chord, 10th primary), (2) chick survival to fledging, and (3) adult return rates in the following breeding season. We found a significant effect of year on overall chick growth patterns, but no effect of tagging or sex-specific impacts. Chick survival did not differ between groups in either year. Regardless of the tagging group, all chicks in 2023 grew wing chords more slowly and reached lower peak body mass compared to chicks in 2022. However, growth rates did not differ between tagging groups within either season. Despite these interannual differences in chick growth, geolocator deployments did not impact breeding performance or adult return rates to the colony. These results emphasize the importance of evaluating device effects to avoid misinterpreting interannual variability as a tagging impact, and reinforce the value of even small-scale comparisons of tagged and non-tagged groups.

Hawaii↗

USGS1994

In vitro growth of the bacterial kidney disease organism Renibacterium salmoninarum on a nonserum, noncharcoal-based "homospecies-metabolite" medium

Laboratory and field trials were conducted to evaluate in vitro growth of Renibacterium salmoninarum in media without serum or charcoal. Growth of this bacterium, the cause of bacterial kidney disease (BKD) in salmonids, is accelerated by addition of a growth enhancing “metabolite” of unknown composition to KDM2 medium, the medium commonly used for isolation of R. salmoninarum . KDM2 medium supplemented with greater than 1% (v/v) metabolite enhanced growth even without addition of either serum or charcoal. Medium containing 5% metabolite (denoted Five-M) allowed optimal growth in laboratory studies and was further evaluated as a primary plating medium for recovery of the bacterium isolated from chinook salmon ( Oncorhynchus tshawytscha ) exhibiting clinical BKD. Recovery rates of R. salmoninarum using Five-M medium were 4% and 36% higher, respectively, than comparable rates using a serum-based medium for the two salmon populations evaluated. Five-M medium is an effective, inexpensive alternative to serum-based or charcoal-based media.

Journal of Wildlife Diseases↗

USGS1999

Evaluation of the flood-pulse concept based on statistical models of growth of selected fishes of the upper Mississippi River system

The flood-pulse concept (FPC) states that annual inundation is the principal force responsible for productivity and biotic interactions in river-floodplain systems. Somatic growth is one component of production, and we hypothesized that, if the FPC applies, growth of fishes that use the moving littoral zone should differ among years with differing flood pattern, whereas nonlittoral fishes would show no such response. Growth of largemouth bass (Micropterus salmoides) and bluegill (Lepomis macrochirus), species that exploit littoral resources, increased during a year having an unusual warm-season flood in the Upper Mississippi River system and was reduced during low-water years. Growth of white bass (Morone chrysops), which do not rely heavily on the littoral zone, did not differ significantly between the extreme-flood and low-water years. Patterns of growth of black crappie (Pomoxis nigromaculatus), which have intermediate dependence on the moving littoral zone, were somewhat ambiguous. These results are consistent with the hypothesis that the FPC applies, at least under certain conditions, to this temperate river system. Our results can also provide an important basis from which to assess some costs and benefits of water level management strategies in large regulated temperate rivers.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2008

Anatomy of a bottleneck: diagnosing factors limiting population growth in the Puerto Rican parrot

The relative importance of genetic, demographic, environmental, and catastrophic processes that maintain population bottlenecks has received little consideration. We evaluate the role of these factors in maintaining the Puerto Rican Parrot (Amazona vittata) in a prolonged bottleneck from 1973 through 2000 despite intensive conservation efforts. We first conduct a risk analysis, then examine evidence for the importance of specific processes maintaining the bottleneck using the multiple competing hypotheses approach, and finally integrate these results through a sensitivity analysis of a demographic model using life-stage simulation analysis (LSA) to determine the relative importance of genetic, demographic, environmental, and catastrophic processes on population growth. Annual population growth has been slow and variable (1.0 6 5.2 parrots per year, or an average k?1.05 6 0.19) from 16 parrots (1973) to a high of 40-42 birds (1997-1998). A risk analysis based on population prediction intervals (PPI) indicates great risk and large uncertainty, with a range of 22?83 birds in the 90% PPI only five years into the future. Four primary factors (reduced hatching success due to inbreeding, failure of adults to nest, nest failure due to nongenetic causes, and reduced survival of adults and juveniles) were responsible for maintaining the bottleneck. Egghatchability rates were low (70.6% per egg and 76.8% per pair), and hatchability increased after mate changes, suggesting inbreeding effects. Only an average of 34% of the population nested annually, which was well below the percentage of adults that should have reached an age of first breeding (41-56%). This chronic failure to nest appears to have been caused primarily by environmental and/or behavioral factors, and not by nest-site scarcity or a skewed sex ratio. Nest failure rates from nongenetic causes (i.e., predation, parasitism, and wet cavities) were low (29%) due to active management (protecting nests and fostering captive young into wild nests), diminishing the importance of nest failure as a limiting factor. Annual survival has been periodically reduced by catastrophes (hurricanes), which have greatly constrained population growth, but survival rates were high under non-catastrophic conditions. Although the importance of factors maintaining the Puerto Rican Parrot bottleneck varied throughout the 30-year period of study, we determined their long-term influence using LSA simulations to correlate variation in demographic rates with variation in population growth (k). The bottleneck appears to have been maintained primarily by periodic catastrophes (hurricanes) that reduced adult survival, and secondarily by environmental and/or behavioral factors that resulted in a failure of many adults to nest. The influence of inbreeding through reduced hatching success played a much less significant role, even when additional effects of inbreeding on the production and mortality of young were incorporated into the LSA. Management actions needed to speed recovery include (1) continued nest guarding to minimize the effects of nest failure due to nongenetic causes; (2) creating a second population at another location on the island --a process that was recently initiated--to reduce the chance that hurricane strikes will cause extinction; and (3) determining the causes of the low percentage of breeders in the population and ameliorating them, which would have a large impact on population growth.

Ecological Monographs↗

USGS1990

Age determinations and growth rates of Pacific ferromanganese deposits using strontium isotopes

87Sr 86Sr ratios, trace element and REE compositions, and textural characteristics were determined for three hydrogenetic Fe-Mn crusts, one hydrothermal deposit, and two mixed hydrothermalhydrogenetic crusts from the Pacific. The Sr isotope data are compared to the Sr seawater curve for the Cenozoic to determine the ages and growth rates of the crusts. The 87Sr 86Sr in the crusts does not increase monotonically with depth as expected if the Sr were solely derived from seawater and perfectly preserved since deposition. This indicates post-depositional exchange of Sr or heterogeneous sources for the Sr originally contained in the crusts. Textures of hydrogenetic crusts generally correlate with Sr isotopic variations. The highest porosity intervals commonly exhibit the highest 87Sr 86Sr ratios, indicating exchange with younger seawater. Intervals with the lowest porosity commonly have lower 87Sr 86Sr and may preserve the original Sr isotopic ratios. Minimum ages of crust growth inception were calculated from dense, low porosity intervals. Growth of the hydrogenetic crusts began at or after 23 Ma, although their substrates are Cretaceous. Estimated average growth rates of the three hydrogenetic crusts vary between 0.9 and 2.7 mm/Ma, consistent with published rates determined by other techniques. Within the Marshall Islands crust, growth rates for individual layers varied greatly between 1.0 and 5.4 mm/Ma. For one crust, very low 87Sr 86Sr ratios occurred in detrital-rich intervals. Hydrothermal Fe-Mn oxide from the active Lau Basin back-arc spreading axis (Valu Fa Ridge) has an 87Sr 86Sr ratio with a predominantly seawater signature ( 87Sr 86Sr 0.709196), indicating a maximum age of 0.9 Ma. One crust from an off-axis seamount west of Gorda Ridge may have begun precipitating hydrogenetically at 0.5 Ma (0.709211), and had increasing hydrothermal or volcanic input in the top half of the crust, indicated by a significantly lower 87Sr 86Sr ratio (0.709052). ?? 1990.

Geochimica et Cosmochimica Acta↗

USGS2004

Reaction rim growth on olivine in silicic melts: Implications for magma mixing

Finely crystalline amphibole or pyroxene rims that form during reaction between silicic host melt and cognate olivine xenocrysts, newly introduced during magma mixing events, can provide information about the timing between mixing and volcanic eruptions. We investigated rim growth experimentally by placing forsteritic olivine in rhyolitic and rhyodacitic melts for times between 25 and 622 h at 50 and 150 MPa, H 2 O-saturated, at the Ni-NiO buffer. Rims of orthopyroxene microlites formed from high-silica rhyolite and rhyodacite melts at 885 ° C and 50 MPa, and in the rhyolite at 150 MPa and 885°C. Rims of amphibole with lesser orthopyroxene formed in the rhyolite at 150 MPa and 800 ° C and in the rhyodacite at 150 MPa and 885 ° C . Irregular, convolute olivine edges and mass balance between olivine, melt, and rim phases show that olivine partly dissolved at all conditions. Iron-rich zones at the exteriors of olivines, which increased in width parabolically with time, show that Fe-Mg interdiffusion occurring in olivines was not outpaced by olivine dissolution. Linear increases of the square of rim widths with time suggest that diffusion within the melt is the rate-controlling process for olivine dissolution and rim growth. Rims grew one-half to one order-of-magnitude faster when melt water contents were doubled, unless conditions were far above the liquidus. Rim growth rate in rhyolite increases from 0.055 ± 0.01 µm 2 /h at 885 ° C and 50 MPa to 0.64 ± 0.13 µ m 2 /h at 800 ° C and 150 MPa. Melt composition has a lesser effect on rim growth rates, with growth rate increasing as melt SiO 2 content decreases. Pyroxene rims on olivines in andesite erupted from Arenal volcano (Costa Rica) grew at a rate of 3.0 ± 0.2 µ m 2 /h over an eleven-year period. This rate is faster than those of the experiments due to lower melt viscosity and higher temperatures, and suggests that a magma mixing event preceded the start of the eruption by days.

American Mineralogist↗

USGS2011

Growth characteristics and Otolith analysis on Age-0 American Shad

Otolith microstructure analysis provides useful information on the growth history of fish (Campana and Jones 1992, Bang and Gronkjaer 2005). Microstructure analysis can be used to construct the size-at-age growth trajectory of fish, determine daily growth rates, and estimate hatch date and other ecologically important life history events (Campana and Jones 1992, Tonkin et al. 2008). This kind of information can be incorporated into bioenergetics modeling, providing necessary data for estimating prey consumption, and guiding the development of empirically-based modeling scenarios for hypothesis testing. For example, age-0 American shad co-occur with emigrating juvenile fall Chinook salmon originating from Hanford Reach and the Snake River in the lower Columbia River reservoirs during the summer and early fall. The diet of age-0 American shad appears to overlap with that of juvenile fall Chinook salmon (Chapter 1, this report), but juvenile fall Chinook salmon are also known to feed on age-0 American shad in the reservoirs (USGS unpublished data). Abundant, energy-dense age-0 American shad may provide juvenile fall Chinook salmon opportunities for rapid growth during the time period when large numbers of age-0 American shad are available. Otolith analysis of hatch dates and the growth curve of age-0 American shad could be used to identify when eggs, larvae, and juveniles of specific size classes are temporally available as food for fall Chinook salmon in the lower Columbia River reservoirs. This kind of temporally and spatially explicit life history information is important to include in bioenergetics modeling scenarios. Quantitative estimates of prey consumption could be used with spatially-explicit estimates of prey abundance to construct a quantitative assessment of the age-0 American shad impact on a reservoir food web.

Oregon, Washington↗

USGS2012

Effect of developmental stage of unfed fry on survival and growth of steelhead released in a stream and hatchery ponds (Study sites: Dworshak Hatchery and North Fork Palouse River; Stock: Dworshak hatchery; Year class: 1996)

We tested whether differences in developmental stage of unfed fry at release affected subsequent survival and growth of steelhead Oncorhynchus mykiss in a stream and hatchery ponds. Differences in development were created by artificially spawning hatchery steelhead from the Clearwater River, Idaho, and incubating their progeny at three different temperatures (means=10.9, 11.3, and 11.7°C). Time between fertilization and maximum alevin wet weight (MAWW) was predicted from incubation temperature using a model. MAWW is equivalent to the button - up fry stage of development. Developmental stages at release were “underdeveloped” (97.7% of model - predicted time to MAWW, mean weight=0.177 g, proportion yolk=0.087), “intermediate” (102.5%, 0.179 g, 0.044), and “overdeveloped” (107.9%, 0.156 g, 0.030). Neither survival nor growth in the hatchery to near the end of the standard one year rearing period differed among groups. In the stream, frequency of overdeveloped fish relative to the other two groups decreased fro m release in May to September, probably indicating lower survival for the overdeveloped fish during that interval since emigration of sub - yearlings is typically negligible. Length in September was less for overdeveloped than for intermediate fish and was in between for underdeveloped fish, suggesting that growth between May and September was less for overdeveloped fish than for intermediate fish. Although changes in relative frequency and size occurred among fry development groups from September to one ye ar later, those changes may have reflected differences in emigration rate during the interval rather than differential survival or growth. Our results show a cost to survival and growth in a stream, but not in a hatchery, from overdevelopment characterize d by loss of weight and yolk reserves relative to fry closer to MAWW at release. We didn’t find any cost from underdevelopment; however, our underdeveloped fry were closer to MAWW than the overdeveloped fry, and they may have been no farther from MAWW than the intermediate fry based on percentage of model - predicted time to MAWW at release.

Idaho, Washington↗

USGS2000

Growth in conventional fields in high-cost areas: A case study

Exploration managers commonly base future drilling decisions on past experience in an area. To do this well, they should consider both discovered and undiscovered resources to characterize total future potential. Discovery-size estimates should be adjusted to account for future field growth; otherwise, the relative efficiency of recent exploration will be undervalued. This study models and projects field growth for pre-1997 discoveries in the U.S. Federal Gulf of Mexico (GOM) Outer Continental Shelf (OCS). Projected additions to reserves for these fields from field growth through 2020 are 5.2 billion bbl of oil and 46 Tcfg. Projections include growth associated with sizable new oil discoveries in deepwater areas and initial reserve additions from new subsalt plays discovered through 1996. This article focuses on the U.S. GOM because it has produced longer than other worldwide offshore areas. Its field-growth profile may be prototypical of other offshore provinces such as the North Sea, Scotian Shelf and deepwater Angola, as well as high-cost onshore areas.

Gulf Of Mexico↗

USGS2011

Structure and dynamics of an upland old- growth forest at Redwood National Park, California

Many current redwood forest management targets are based on old-growth conditions, so it is critical that we understand the variability and range of conditions that constitute these forests. Here we present information on the structure and dynamics from six one-hectare forest monitoring plots in an upland old-growth forest at Redwood National Park, California. We surveyed all stems =20 cm DBH in 1995 and 2010, allowing us to estimate any systematic changes in these stands. Stem size distributions for all species and for redwood ( Sequoia sempervirens (D. Don) Endl.) alone did not appreciably change over the 15 year observation interval. Recruitment and mortality rates were roughly balanced, as were basal area dynamics (gains from recruitment and growth versus losses from mortality). Similar patterns were found for Sequoia alone. The spatial structure of stems at the plots suggested a random distribution of trees, though the pattern for Sequoia alone was found to be significantly clumped at small scales (< 5 m) at three of the six plots. These results suggest that these forests, including populations of Sequoia, have been generally stable over the past 15 years at this site, though it is possible that fire exclusion may be affecting recruitment of smaller Sequoia (< 20 cm DBH). The non-uniform spatial arrangement of stems also suggests that restoration prescriptions for second-growth redwood forests that encourage uniform spatial arrangements do not appear to mimic current upland old-growth conditions.

California↗

USGS2016

Hydrologic effects on diameter growth phenology for Celtis laevigata and Quercus lyrata in the floodplain of the lower White River, Arkansas

Bottomland hardwood (BLH) forests represent an extensive wetland system in the Mississippi Alluvial Valley and southeastern USA, and it is currently undergoing widespread transition in species composition. One such transition involves increased establishment of sugarberry (Celtis laevigata), and decreased establishment of overcup oak (Quercus lyrata). The ecological mechanisms that control this transition are not well understood. We measured monthly diameter growth with dendrometer bands on 86 sugarberry and 42 overcup oak trees at eight sites in the floodplain of the White River (AR, USA) with differing hydrologic regimes. For both species, growth attenuated earlier at drier sites compared to wetter sites. Overcup oak grew slightly longer through late August, suggesting its growth period extends across both wet and dry periods. In contrast, sugarberry growth rate decreased substantially by mid-July. While these results did not necessarily indicate a mechanism for increased prominence of sugarberry, they suggest sugarberry growing season does not as much coincide with the typically drier period of late summer and may be less affected by these conditions. Overcup oak grows later into the dry season and water table conditions during this period may determine if overcup oak benefits from this relatively extended growth period.

Conference Paper↗

USGS2011

Long term retention, survival, growth, and physiological indicators of salmonids marked with passive integrated transponder tags

To track individuals in situ, over 12 million salmon and trout have been marked with passive integrated transponder (PIT) tags in the Columbia River Basin, USA. However, few studies have examined long term tag retention as well as tag effects on juvenile salmon and trout. We marked juvenile coho salmon Oncorhynchus kisutch (N = 207), steelhead (anadromous rainbow trout) O. mykiss (N = 221), cutthroat trout O. clarkii (N = 202) and bull trout Salvelinus confluentus (N = 180) with 12, 19, or 23 mm PIT tags and examined tag retention, survival, growth, and physiological performance over a six month period in a laboratory environment. PIT tag retention rates were high for coho salmon (100%), steelhead (95%), cutthroat trout (97%), and bull trout (99%), regardless of tag size. Survival was also high for coho (99%), steelhead (99%), cutthroat trout (97%), and bull trout (88%) and did not vary among tag sizes. Short term individual growth rates for coho salmon marked with 12 mm tags were significantly higher than those marked with 19 mm and 23 mm PIT tags. Likewise, steelhead trout individual growth rates were lower for fish marked with 23 mm PIT tags followed by 19 and 12 mm tags. Conversely, long-term growth rates were positive and not affected by tag size. There were no significant effects of tag size or marking on coho gill Na+, K+, -ATPase activity (µmol ADP x mg protein–1 h–1) and plasma osmolality (µmol kg–1) or bull trout hepatosomatic indices. Our study suggests that marking juvenile salmonids with PIT tags results in high retention with little effect upon their survival, growth, and important physiological indicators regardless of tag size in a laboratory environment.

American Fisheries Society Symposium↗