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1801. [Article] Vertebral elemental markers in elasmobranchs : potential for reconstructing environmental history and population structure
Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns ...Citation Citation
- Title:
- Vertebral elemental markers in elasmobranchs : potential for reconstructing environmental history and population structure
- Author:
- Smith, Wade D.
Differences in the chemical composition of calcified structures can be used to reveal natal origins, connectivity, metapopulation structure, and reconstruct the environmental history or movement patterns of many marine organisms. Sharks, skates, and rays (elasmobranchs) lack the calcified structures, known as otoliths, that are typically used for geochemical studies of dispersal and natal origin in fishes. If the incorporation of elements into shark and ray vertebrae is related to environmental conditions, the geochemical composition of cartilaginous vertebrae may also serve as natural tags and records of environmental history in elasmobranch populations. I used complementary laboratory and field studies to address several key assumptions regarding the incorporation of elements in elasmobranch vertebrae, providing the first detailed studies to assess relationships between water and vertebral chemical composition and the spatial and temporal variation of vertebral elemental signatures in this subclass of fishes. To validate the uptake and incorporation of elements from water to vertebrae, I conducted two laboratory studies using round stingrays, Urobatis halleri, as a model species. First, I examined the effects of temperature (16°, 18°, 24° C) on vertebral elemental incorporation (Li/Ca, Mg/Ca, Mn/Ca, Zn/Ca, Sr/Ca, Ba/Ca) and found that temperature had strong, negative effects on the uptake (measured as a partition coefficient, D[subscript Element]) of magnesium and Ba and positively influenced manganese incorporation. Second, I tested the relationship between water and vertebral elemental composition by manipulating dissolved barium (Ba) concentrations (1x, 3x, 6x ambient concentrations) and found significant differences among rays from each treament. I also evaluated the influence of natural variation in somatic growth and vertebral precipitation rates on elemental incorporation. Finally, I examined the accuracy of classifying individuals to known environmental histories (temperature and barium treatments) using vertebral elemental composition. There were no significant relationships between elemental incorporation and somatic growth or vertebral precipitation rates for any elements with the exception of Zn. Relationships between somatic growth rate and D[subscript Zn] were, however, inconsistent and inconclusive. Elemental variation of vertebrae reliably distinguished U. halleri based on temperature (85%) and [Ba] (96%) history. These results support the assumption that vertebral elemental composition reflects the environmental conditions during deposition and validates the use of vertebral elemental signatures as natural markers in an elasmobranch. To evaluate the utility of vertebral geochemistry as intrinsic markers of natal origin, I collected vertebrae of young-of-the-year scalloped hammerhead sharks (Sphyrna lewini) from artisanal fishery landings at six sites along the Pacific coast of Mexico and Costa Rica between 2007-2009. A total of 386 vertebrae were used to assess patterns of spatial and temporal variation in elemental composition using laser ablation-inductively coupled plasma mass spectrometry. A protracted pupping period was confirmed for S. lewini, with newborn pups being recorded from May through mid-October. Natal elemental signatures detected in the vertebrae of the sharks varied significantly among sites and could be used to identify source populations. All element-to-calcium ratios included in these analyses (Li/Ca, Mg/Ca, V/Ca, Cr/Ca, Mn/Ca, Rb/Ca, Sr/Ca, Ba/Ca, Pb/Ca) were useful for the discerning natal origins of sharks; however, Ba, Sr, Mn, and Mg ratios most consistently generated the greatest discriminatory power based on step-wise discriminant function analyses. Classification accuracy to putative nursery areas (natal signature) and location of capture (edge signature) based on step-wise discriminant function analysis ranged from low (30-60%) to high (80-100%) depending on the degree of spatial and temporal resolution by which the data were filtered for analysis (e.g. pooled across months, early season, late season). All classification accuracies exceeded chance expectations and assignment to putative nursery areas and sites of capture were accomplished with up to 100% accuracy in several models. I found significant intra-annual differences in natal elemental signatures within the three primary study sites, which likely contributed to the low assignment accuracies when data were grouped across months of collection. Significant differences in natal elemental signatures were also detected across years. However, pair-wise analyses revealed that site-specific inter-annual variation was driven by differences associated with samples collected in 2009. Natal elemental signatures were similar between 2007 and 2009, indicating some consistency in site-specific vertebral chemistry across years. These results confirmed that vertebral elemental signatures can be applied to distinguish individuals across small (5s km), moderate (100s km), and large spatial scales (>1000 km). The potential for intra-annual variation in natal signatures within a year-class highlights the importance of cohort-specific analyses and the development of a spatial atlas of natal vertebral elemental signatures for studies of natal origin and population connectivity. The findings of my laboratory validation experiments and field study establish that geochemical analyses of vertebrae can provide reliable information on the spatial ecology and environmental history of shark and ray populations. The use of elemental signatures offers a new approach for the study and conservation of this historically vulnerable group of fishes.
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1802. [Article] Patterns and mechanisms : postcopulatory sexual selection and sexual conflict in a novel mating system
Postcopulatory sexual selection—sperm competition and cryptic female choice—has become a major area of research over the past 40 years. Within this field there are many outstanding questions at every level ...Citation Citation
- Title:
- Patterns and mechanisms : postcopulatory sexual selection and sexual conflict in a novel mating system
- Author:
- Friesen, Christopher R.
Postcopulatory sexual selection—sperm competition and cryptic female choice—has become a major area of research over the past 40 years. Within this field there are many outstanding questions at every level of analysis, from proximate to ultimate. The fitness consequences for both sexes in the period after copulation and before fertilization are considerable, but are obscured within the female reproductive tract. Our understanding of postcopulatory mechanisms is especially sparse in taxa other than birds and insects. Nearly nothing is known in reptiles except that multiple paternity is common and widespread, and often results from long-term sperm storage across breeding seasons. We present some of the very first data on the determinants of fertilization success in the context of sperm competition in reptiles, a group that accounts for 30% of terrestrial vertebrates. In the first chapter, "Asymmetric gametic isolation between two populations of red-sided garter snakes", we discuss the use of between-population crosses to reveal gametic isolation. The effect of population density and operational sex ratios on mating systems and the speciation process has fueled theoretical debate. We attempted to address these issues using two populations of red-sided garter snakes (Thamnophis sirtalis parietalis) from Manitoba, Canada. Our study populations differ markedly in their density mating aggregations, with a 10-fold difference between them. Using microsatellite markers for paternity analysis of litters produced from within and between population crosses. We found that the population with highest aggregation density, and presumably with the highest level of sexual conflict (i.e., when the evolutionary interests of the sexes differ) over mating, was also the population that exhibited homotypic sperm precedence. The less dense population showed a distinct postcopulatory male-size advantage. We also demonstrated that sperm stored within the female over hibernation can father 20-30% of offspring in a litter. In the second chapter, "Sperm competition and mate-order effects in red-sided garter snakes", we test whether females use mate-order effects to ensure that a larger (fitter) male will sire her offspring. Does that second male should have precedence in sperm competition? We tested for second-male precedence using singly-mated females that mated with a second male. Average proportion of paternity was shared equally among the first (P₁, i.e., proportion of offspring from a litter fathered by the first male to mate) and second males (P₂) to mate, and stored sperm (P[subscript ss]). This may be a case where last male precedence breaks down with more than two males. All females were spring virgins (they had not mated that spring, but may have stored sperm from fall matings); thus sperm stored presumably from fall matings is important in this system. As the interval between matings increased P₁ increased at the expense of P[subscript ss]. As the second male to mate's copulation duration increased, P₁ also increased at the expense of P₂. This last result may indicate female influence over sperm transfer during coerced matings. Copulatory plugs (CPs) are found in many taxa, but the functional significance is debated. Male garter snakes produce a gelatinous copulatory plug during mating that occludes the opening of the female reproductive tract for approximately two days. In chapter three, "Not just a chastity belt: the role of mating plugs in red-sided garter snakes revisited", we experimentally tested the role of the CPs. In snakes, sperm are produced in the testes and delivered through the ductus deferens, and the copulatory plug is thought to be produced by the sexual segment of the kidney and conveyed through the ureter. We manipulated the delivery of the two fluids separately by ligating the ducts. We confirmed that the CP is not formed in ureter-ligated males and that sperm leaks out immediately after copulation. The CP is analogous to a spermatophore. The protein matrix contains most of the sperm which are liberated as the plug dissolves within the female's vaginal pouch. One of the fundamental principles in sperm competition is that increased sperm numbers increase the odds of winning in competitions for fertilization success and males will adjust their ejaculate relative to competition and the quality of his mate. In chapter four, "Sperm depleted males and the unfortunate females who mate with them", we detect significant among-male variation in the number of sperm ejaculated, and that male mate-order reduces sperm numbers. Male sperm numbers drop significantly from one mating to the next, and this has implications for sperm competiveness, as Thamnophis sirtalis exhibits a disassociated reproductive tactic, in that sperm stores are produced outside the breeding season, and thus cannot be replenished after mating. Interestingly, however, the on average the mobility of the sperm increased for a male's second mating. Therefore, increased sperm quality may compensate for reduced numbers in a competitive context. Further, females increase their remating rate when mating with males that are unable to deliver sperm. In chapter five, "Sexual conflict during mating in red-sided garter snakes as evidenced by genital manipulation", we revisited the CP in the context of sexual conflict. Sex-differences in optimal copulation duration can be a source of conflict, as increased copulation duration may be advantageous for males as it delays female remating. Males of many species actively guard females to prevent them from remating, and in some cases males produce copulatory plugs to prevent remating. If precopulatory choice is limited at the time of her first mating, conflict may be especially onerous to a female. The size of the plug is influenced by the copulation duration. We experimentally tested the contribution of male and female control over copulation duration. We ablated the largest basal spine on the male's hemipene and found a reduction in copulation duration and an increase in the variation of plug mass. Further, we anesthetized the female's cloaca and found copulation duration increased, which suggests that males benefit from increased copulation duration while females actively try to reduce copulation duration. Therefore, sexual conflict is manifest in divergent copulation duration optima for males and females.
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1803. [Article] Food habits and diet quality of deer and cattle and herbage production of a sagebrush-grassland range
Research was conducted on the Keating rangelands in north-eastern Oregon to determine the food habits of deer and cattle and similarity of their diets, and to estimate deer and cattle months of grazing ...Citation Citation
- Title:
- Food habits and diet quality of deer and cattle and herbage production of a sagebrush-grassland range
- Author:
- Hilken, Thomas O.
Research was conducted on the Keating rangelands in north-eastern Oregon to determine the food habits of deer and cattle and similarity of their diets, and to estimate deer and cattle months of grazing on both a quantitative and nutritional basis. Data were collected during the winters of 1978-1979, 1979-1980 and during the spring and fall of 1979 and 1980. In the Crystal Palace, Tucker Creek and Spring Creek study areas, field fecal collections were made and the microhistological method was used in the laboratory to determine the food habits of both deer and cattle. Similarity indices were calculated comparing food habits of both deer and cattle. In delineated plant communities, available herbaceous forage was estimated within 0.5m² circular plots employing a double sampling technique, and available browse was estimated employing a multiple linear regression technique. Subsamples of available forage were analyzed for in vitro dry matter digestibility and crude protein. An extensive literature review was conducted to determine nitrogen (N) and metabolizable energy (ME) requirements of both deer and cattle. Cattle and deer months of grazing were calculated for each plant community on a quantitative (i.e., forage biomass) and nutritional (i.e., metabolizable energy and nitrogen) basis employing the resources available following relationships: number supported = resources available/resources required. Management recommendations were made based on data collected in this study. Grass was the most dominant forage consumed by cattle, while deer consumed both grass and browse. Forbs were not an important dietary constituent for either cattle or deer. During the early winter period of 1978-1979, browse and grass averaged 57.4 percent and 1.6 percent of the deer diets, respectively. However, during the late winter period of 1978-1979, browse and grass averaged 40.2 percent and 31.5 percent of the deer diets, respectively. During the 1979-1980 winter, browse and grass averaged 35.4 percent and 51.9 percent of the deer diets, respectively. The predominant grass and browse consumed by deer was Sandberg's bluegrass and big sagebrush, respectively. During the spring period, crested wheatgrass, cheatgrass and Sandberg's bluegrass averaged 21.8, 29.1 and 19.5 percent of cattle diets, respectively. During the fall period,.cheatgrass and Sandberg's bluegrass averaged 30.4 and 24.9 percent of cattle diets, respectively. Diet similarity ranged from 27.1 percent to 52.8 percent while the average spring overlap for both years was 37 percent and the average fall overlap was 50 percent. Most of the dietary overlap occurred on Sandberg's bluegrass. The literature review revealed that on a forage biomass basis a cow-calf pair in spring required 14 kg/day, while a dry pregnant cow in the fall required 10 kg/day. On an energy and nitrogen basis, a nursing cow required 26.6 Meal/day of ME and 206 g of N, while a dry pregnant cow required 10.0 Meal/day of ME and 94.5 g of N. On a forage biomass basis, a wintering adult deer required .9 kg of forage per day while a fawn required .6 kg per day. Considering the length of the winter period, the energy obtained by catabolism of fat, and the energy and nitrogen required in gesta tion, I determined that during the early and late winter periods of 1978-1979 deer required 1.81 and 1.80 Meal/day of ME and during the 1979-1980 winter, they required 1.73 Meal/day of ME. The literature also revealed that a wintering deer required 12.9 g of N per day. Quantitative forage analysis showed that depending upon study area and pasture on a kg/ha basis the predominant grasses available to cattle were crested wheatgrass, Sandberg's bluegrass and cheatgrass. Determination of available browse biomass was made employing a multiple linear regression model for mountain big sagebrush (log y = -6.37 + .9337 log H + 1.49 log W₂), and a simple linear regression model for gray rabbitbrush (log y = -3.70 + 1.81 log W) and basin big sagebrush (log y = -3.84 + .9870 log A). Depending upon study area and plant community, quantitative analysis of the forage showed that big sagebrush and Sandberg's bluegrass were the dominant species available to deer. Early spring grazed pastures could carry more AUMS on a nutritional basis than on a quantitative basis. Pastures sampled in late spring showed that total AUMS on a forage quantity basis exceeded those on a nutritional basis. During the fall on an old-growth (i.e., previous year's growth) and fall growth basis, total AUMS based on N generally exceeded those based on ME or forage quantity, except in the crested wheatgrass-dominated pasture where more AUMS were calculated on a quantity basis than on a nutritional basis. On a fall-growth-only basis, more AUMS were calculated on a nutritional basis than on a quantity basis. Generally, the least number of AUMS could be carried on the medusahead communities while the most AUMS could be carried on the crested wheatgrass seedings. Deer months calculated for the two winters across the three study areas showed more deer months per plant community were calculated on a forage quantity basis than on an ME or N basis. However, an exception to this trend occurred in the grassland com munities where more deer months were calculated on an N basis than on an ME or forage quantity basis. Generally, the most deer months were calculated for the basin big sagebrush communities while the least number of deer months were calculated on the medusahead communities.
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1804. [Article] Investigation of the structural influence on the properties of functional inorganic oxides
While properties are extremely important from an application point of view, it is crucial to have a detailed understanding of the underlying structural influence. Once a concrete correlation between the ...Citation Citation
- Title:
- Investigation of the structural influence on the properties of functional inorganic oxides
- Author:
- Laurita-Plankis, Geneva
While properties are extremely important from an application point of view, it is crucial to have a detailed understanding of the underlying structural influence. Once a concrete correlation between the structure and the observed property is established, rational design of novel materials with optimized properties can be realized. These optimized materials lead to advancements in technology in a variety of applications, including new building materials, faster electronic devices, and more efficient catalysts. This dissertation examines the structural influence on the observed properties in a series of metal oxide materials for electronic and energy applications. A series of pyrochlores Ag[subscript 1-nx]M[superscript n][subscript x]SbO₃ (M = Na⁺, K⁺, Tl⁺, and Cd²⁺) has been studied to evaluate the structural influence on the samples' photocatalytic activity. A complete solid solution between the anion-deficient pyrochlore Ag₂Sb₂O₆ and the ideal pyrochlore Cd₂Sb₂O₇ has been synthesized through the standard solid state ceramic method. Each composition has been characterized by various different techniques, including powder X-ray diffraction, optical spectroscopy, electron paramagnetic resonance and ¹²¹Sb Mössbauer spectroscopy. Computational methods based on density functional theory complement this investigation. Photocatalytic activity has been studied, and transport properties have been measured on pellets densified by spark plasma sintering. The analysis of the data collected from these various techniques enables a comprehensive characterization of the complete solid solution and revealed an anomalous behavior in the Cd-rich end of the solid solution, which has been proposed to arise from a possible radical O⁻ species in small concentrations. Polycrystalline samples of the pyrochlore series Ag[subscript 1-nx]M[superscript n][subscript x]SbO₃ (M = Na⁺, K⁺ and Tl[superscript +/3+]) have been structurally analyzed through total scattering techniques and evaluated for photocatalytic activity. The upper limits of x obtained are 0.08 for Na, 0.16 for K, and 0.17 for Tl. The Ag⁺ cation occupies a site with inversion symmetry on a 3-fold axis. When the smaller Na⁺ cation substitutes for Ag⁺, it is displaced by about 0.6 Å perpendicular to the 3-fold axis to achieve shorter Na-O bond distances. When the larger Tl⁺ cation substitutes for Ag⁺, it is displaced by about 1.14 Å along the 3-fold axis and achieves an environment typical of a lone pair cation. Some of the Tl³⁺ from the precursor remains unreduced, leading to a formula of Ag₀.₇₇Tl⁺₀.₁₃Tl³⁺₀.₀₄SbO₃.₀₄. The position of the K⁺ dopant was effectively modeled assuming that K⁺ occupied the same site as Ag⁺. The expansion of the lattice caused by substitution of the larger K⁺ and Tl⁺ cations results in longer Ag-O bond lengths, which would reduce the overlap of the Ag 4d and O 2p orbitals that compose the valence band maximum. Substitution of the smaller Na⁺ results in a decrease in the Ag-O bond distance, thus increasing the overlap of the Ag 4d and O 2p orbitals. An increase in the photocatalytic activity has been observed for the nominal composition Ag₀.₈Na₀.₂SbO₃ made through solid state synthesis, and this is attributed to both the slight decrease in the band gap and the increase in pore dimensions compared to the parent compound AgSbO₃. The structural transitions in Cd₂Nb₂O[subscript 7-x]S[subscript x] (x = 0, 0.25, 0.5, and 0.7) have been studied to determine the origin of ferroelectricity in pyrochlore oxides. For x = 0, 0.25, and 0.5 peak splitting indicative of a transition to orthorhombic symmetry is observed below the transition temperature. In the x = 0.7 sample, the evolution of new peaks suggest a cubic space group is retained below the phase transition accompanied by a loss of the face-centering symmetry. The observed lowering of symmetry may be responsible for the transition into a ferroelectric phase, and may be driven by a strong displacement of both the Nb and Cd from the high- to low-symmetry structures. The S content may drive the stability if different ferroelectric phases, as no trend was observed with increasing content in the ferroelectric Curie temperatures of the samples. The structure of the hollandites A[subscript x]Ru₄O₈ (A = K⁺, Rb⁺) has been studied through total scattering techniques upon cation exchange with Na⁺ on the A-site to evaluate the effect on the quasi-one dimensional (Q1D) nature of these materials. It is observed that the A-site of the hollandite structure is not fully occupied when A = K⁺, Rb⁺, and full A-site occupancy is achieved after ion exchange with NaNO₃. All samples exhibit Pauli paramagnetism, and this is primarily due to a large low temperature range of metallic conduction. The double chains of edge-shared RuO₆ octahedra and corner shared double chains found in the channel of the hollandite structure promotes two conduction mechanisms: ρ∥ (intra-chain metallic) and ρ⊥ (inter-chain hopping). The coexistence of ρ∥ and ρ⊥ gives rise to metallic conductivity below T[subscript max] (suppressed hopping at lower temperature) and semiconductivity above T[subscript max] (intra-chain mean free path becomes smaller than the inter-chain hopping distance), exhibiting the Q1D conduction at lower temperatures. The inter-chain distance is larger in the Rb-containing samples, and consequently the region dominated by intra-chain metallic conduction increases, along with an increase in T[subscript max].
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1805. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2016 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), ...Citation Citation
- Title:
- Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2016 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), developed to mitigate for wild fish production lost as a result of construction of the four lower Snake River dams. Hatchery Chinook and steelhead smolts in the Snake River basin are produced at LSRCP hatcheries in Washington, Idaho and Oregon. Subsequent adult returns are meant to provide tribal and recreational (sport) fisheries and, in some cases, enhance natural spawner numbers. The Oregon Department of Fish and Wildlife (ODFW) initiated the Imnaha and Grande Ronde spring Chinook hatchery program in 1982 under the LSRCP. Subsequent program management has been coordinated between ODFW, the Confederated Tribes of the Umatilla Indian Reservation (CTUIR), and the Nez Perce Tribe (NPT). The Imnaha and Grande Ronde River hatchery programs are comprised of five components, each with smolt acclimation and adult collection facilities located on the Imnaha River, upper Grande Ronde River, Lookingglass and Catherine Creeks, and the Lostine River. The Lostine River program interacts with natural production within the broader Wallowa-Lostine population unit. Other hatchery program components are discrete to specific populations indicated. The Lookingglass Creek portion of the program focuses on reintroduction of spring Chinook to that stream and targets the release of 250,000 smolts, annually. Each of the four remaining program components integrates natural-origin fish returning to each respective tributary into production. Smolt release goals, developed to meet LSRCP mitigation responsibilities; include 490,000 for the Imnaha, 250,000 for the Lostine and upper Grande Ronde rivers, and 150,000 for Catherine Creek. Fisheries that target returns to the Imnaha and Grande Ronde hatchery programs are guided by Fishery Management and Evaluation Plans (FMEP), approved by NOAA fisheries under limit 4 of the final 4(d) rule of the Endangered Species Act (ODFW 2011, ODFW and WDFW 2012). The objective of the FMEP is to provide recreational fishing opportunities and related benefits derived from harvest of Imnaha and Grande Ronde basin hatchery-origin spring Chinook salmon in Oregon and Washington in a manner that supports the continued survival and future recovery of natural-origin Chinook salmon. Each respective FMEP utilizes a management framework for harvest of adipose-clipped, hatchery-origin Snake River spring/summer Chinook salmon using abundance-based sliding scales to set annual fishery impacts. Fisheries are prescribed maximum impact rates for both direct and incidental mortality of natural-origin adult salmon in sport and tribal fisheries. Impacts are assessed for each population in relation to critical and minimum abundance thresholds (MAT) as described by the Interior Columbia Technical Recovery Team (ICTRT 2007). Population designations for the Imnaha and Grande Ronde Basins are listed in Table 1, and are based upon an analysis of Chinook salmon life history traits, distribution, abundance, and productivity, and geographical and ecological characteristics of the landscape within the Snake River Spring/Summer Chinook Salmon ESU (McElhany et al. 2000). The abundance-based harvest rate schedule for Imnaha and Grande Ronde Basin fisheries to be shared by all fishing entities in the basin as described in Table 2. Harvest is not considered when hatchery run size does not exceed the number of adults identified for broodstock and supplementation needs as described by sliding scale management plans set for each population’s hatchery program. Surplus is generally defined as the adult hatchery run projection less hatchery adults needed for broodstock. This approach limits sport harvest during years when wild fish runs are below MAT and hatchery fish runs are of similar size. In addition, near the lower end of the harvest rate scale, fisheries are not implemented until the allowable hatchery fish harvest exceeds 20 fish due to potential to over harvest within a single week. Fishery impacts to listed Snake River spring/summer Chinook salmon are assessed on a collective basis (i.e., the sum of recreational and tribal fisheries) by NOAA fisheries. However, the coordination of impact amongst states and tribes is a key component of executing conservation-based fisheries in the Imnaha and Grande Ronde Basins. Co-managers within each basin have developed, and implement annually, an impact sharing agreement that is described in Table 3. Within each fishery scenario, this agreement provides tribal fisheries more of the natural-origin impacts to reflect the non-selective nature of traditional fishing techniques. Recreational fisheries are provided a larger portion of the hatchery harvest such that all available impacts (hatchery and natural collectively) are shared equally (Table 3). Recreational fisheries administered by the states limit harvest (retention) of spring/summer Chinook hatchery-origin salmon with a clipped adipose fin (as evidenced by a healed scar). All salmon with an intact adipose fin (natural-origin) must be released back to the water. Therefore, incidental mortality impacts occur from catch and release of unclipped Snake River spring/summer Chinook salmon in fisheries targeting adipose-clipped hatchery Chinook salmon, and/or from the illegal retention of unclipped fish. It is generally assumed throughout the Columbia River Basin that the mortality rate resulting from the catch and release of salmon in fisheries is 10%. However, for Lookingglass Creek comanagers, with concurrence from NOAA fisheries, assume a slightly lower rate of 7.5% (ODFW and WDFW 2012). As stated in the FMEP, fisheries are adjusted or terminated when the total ESA take limit identified in Table 2 and 3 has been reached. Therefore, once fisheries are initiated regular monitoring is required to ensure consistency with co-manager agreements and FMEP requirements. The objective of this LSRCP project was to conduct statistical creel surveys to determine spring Chinook and steelhead ESA impact levels, harvest and release rates, and to inform decisions regarding fishery status in the Imnaha and Grande Ronde Basins in 2016. In this report, we describe creel surveys conducted and estimates of angler effort, catch, and harvest. In addition we compare these estimates in relation to estimates of natural and hatchery-origin returns to each population to assess consistency with prescribed impacts under FMEP guidelines. Lower Snake River Compensation Plan (LSRCP) ODFW
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1806. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2015 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), ...Citation Citation
- Title:
- Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2015 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), developed to mitigate for wild fish production lost as a result of construction of the four lower Snake River dams. Hatchery Chinook and steelhead smolts in the Snake River basin are produced at LSRCP hatcheries in Washington, Idaho and Oregon. Subsequent adult returns are meant to provide tribal and recreational (sport) fisheries and, in some cases, enhance natural spawner numbers. The Oregon Department of Fish and Wildlife (ODFW) initiated the Imnaha and Grande Ronde spring Chinook hatchery program in 1982 under the LSRCP. Subsequent program management has been coordinated between ODFW, the Confederated Tribes of the Umatilla Indian Reservation (CTUIR), and the Nez Perce Tribe (NPT). The Imnaha and Grande Ronde River hatchery programs are comprised of five components, each with smolt acclimation and adult collection facilities located on the Imnaha River, upper Grande Ronde River, Lookingglass and Catherine Creeks, and the Lostine River. The Lostine River program interacts with natural production within the broader Wallowa-Lostine population unit. Other hatchery program components are discrete to specific populations indicated. The Lookingglass Creek portion of the program focuses on reintroduction of spring Chinook to that stream and targets the release of 250,000 smolts. Each of the four remaining program components integrates natural-origin fish returning to each respective tributary into production. Smolt release goals, developed to meet LSRCP mitigation responsibilities; include 490,000 for the Imnaha, 250,000 for the Lostine and upper Grande Ronde rivers, and 150,000 for Catherine Creek. Fisheries that target returns to the Imnaha and Grande Ronde hatchery programs are guided by Fishery Management and Evaluation Plans (FMEP), approved by NOAA fisheries under limit 4 of the final 4(d) rule of the Endangered Species Act (ODFW 2011, ODFW and WDFW 2012). The objective of the FMEP is to provide recreational fishing opportunities and related benefits derived from harvest of Imnaha and Grande Ronde basin hatchery-origin spring Chinook salmon in Oregon and Washington in a manner that supports the continued survival and future recovery of natural-origin Chinook salmon. Each respective FMEP utilizes a management framework for harvest of adipose-clipped, hatchery-origin Snake River spring/summer Chinook salmon using abundance-based sliding scales to set annual fishery impacts. Fisheries are prescribed maximum impact rates for both direct and incidental mortality of natural-origin adult salmon in sport and tribal fisheries. Impacts are assessed for each population in relation to critical and minimum abundance thresholds (MAT) as described by the Interior Columbia Technical Recovery Team (ICTRT 2007). Population designations for the Imnaha and Grande Ronde Basins are listed in Table 1, and are based upon an analysis of Chinook salmon life history traits, distribution, abundance, and productivity, and geographical and ecological characteristics of the landscape within the Snake River Spring/Summer Chinook Salmon ESU (McElhany et al. 2000). The abundance-based harvest rate schedule for Imnaha and Grande Ronde Basin fisheries to be shared by all fishing entities in the basin is described in Table 2. Harvest is not considered when hatchery run size does not exceed the number of adults identified for broodstock and supplementation needs as described by sliding scale management plans set for each population’s hatchery program. Surplus is generally defined as the adult hatchery run projection less hatchery adults needed for broodstock. This approach limits sport harvest during years when wild fish runs are below MAT and hatchery fish runs are of similar size. In addition, near the lower end of the harvest rate scale, fisheries are not implemented until the allowable hatchery fish harvest exceeds 20 fish due to potential to over harvest within a single week. Fishery impacts to listed Snake River spring/summer Chinook salmon are assessed on a collective basis (i.e., the sum of recreational and tribal fisheries) by NOAA fisheries. However, the coordination of impact amongst states and tribes is a key component of executing conservation-based fisheries in the Imnaha and Grande Ronde Basins. Co-managers within each basin have developed, and implement annually, an impact sharing agreement that is described in Table 3. Within each fishery scenario, this agreement provides tribal fisheries more of the natural-origin impacts to reflect the non-selective nature of traditional fishing techniques. Recreational fisheries are provided a larger portion of the hatchery harvest such that all available impacts (hatchery and natural collectively) are shared equally (Table 3). Recreational fisheries administered by the states limit harvest (retention) of spring/summer Chinook hatchery-origin salmon with a clipped adipose fin (as evidenced by a healed scar). All salmon with an intact adipose fin (natural-origin) must be released back to the water. Therefore, incidental mortality impacts occur from catch and release of unclipped Snake River spring/summer Chinook salmon in fisheries targeting adipose-clipped hatchery Chinook salmon, and/or from the illegal retention of unclipped fish. It is generally assumed throughout the Columbia River Basin that the mortality rate resulting from the catch and release of salmon in fisheries is 10%. However, for Lookingglass Creek comanagers, with concurrence from NOAA fisheries, assume a slightly lower rate of 7.5% (ODFW and WDFW 2012). As stated in the FMEP, fisheries are adjusted or terminated when the total ESA take limit identified in Table 2 and 3 has been reached. Therefore, once fisheries are initiated regular monitoring is required to ensure consistency with co-manager agreements and FMEP requirements. The objective of this LSRCP project was to conduct statistical creel surveys to determine spring Chinook and steelhead ESA impact levels, harvest and release rates, and to inform decisions regarding fishery status in the Imnaha and Grande Ronde Basins in 2015. In this report, we describe creel surveys conducted and estimates of angler effort, catch, and harvest. In addition we compare these estimates in relation to estimates of natural and hatchery-origin returns to each population to assess consistency with prescribed impacts under FMEP guidelines. Lower Snake River Compensation Plan (LSRCP) ODFW
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1807. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2014 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), ...Citation Citation
- Title:
- Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2014 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), developed to mitigate for wild fish production lost as a result of construction of the four lower Snake River dams. Hatchery Chinook and steelhead smolts in the Snake River basin are produced at LSRCP hatcheries in Washington, Idaho and Oregon. Subsequent adult returns are meant to provide tribal and recreational (sport) fisheries and, in some cases, enhance natural spawner numbers. The Oregon Department of Fish and Wildlife initiated the Imnaha and Grande Ronde spring Chinook hatchery program in 1982 under the LSRCP. Subsequent program management has been coordinated between ODFW, Confederated Tribes of the Umatilla Indian Reservation (CTUIR), and Nez Perce Tribe (NPT). The Imnaha and Grande Ronde River hatchery programs are comprised of five components, each with smolt acclimation and adult collection facilities located on the Imnaha River, upper Grande Ronde River, Lookingglass and Catherine Creeks, and the Lostine River. The Lostine River program interacts with natural production within the broader Wallowa-Lostine population unit. Other hatchery program components are discrete to specific populations indicated. The Lookingglass Creek portion of the program focuses on reintroduction of spring Chinook to that stream and targets the release of 250,000 smolts originating from the Catherine Creek population. Each of the four remaining program components integrates natural-origin fish returning to each respective tributary into production. Smolt release goals, developed to meet LSRCP mitigation responsibilities, include 490,000 for the Imnaha, 250,000 for the Lostine and upper Grande Ronde rivers, and 150,000 for Catherine Creek. Fisheries that target returns to the Imnaha and Grande Ronde hatchery programs are guided by Fishery Management and Evaluation Plans (FMEP), approved by NOAA fisheries under limit 4 of the final 4(d) rule of the Endangered Species Act (ODFW 2011, ODFW and WDFW 2012). The objective of the FMEP is to provide recreational fishing opportunities and related benefits derived from harvest of Imnaha and Grande Ronde basin hatchery-origin spring Chinook salmon in Oregon and Washington in a manner that supports the continued survival and future recovery of natural-origin Chinook salmon. Each respective FMEP utilizes a management framework for harvest of adipose-clipped, hatchery-origin Snake River spring/summer Chinook salmon using abundance-based sliding scales to set annual fishery impacts. Fisheries are prescribed maximum impact rates for both direct and incidental mortality of natural-origin adult salmon in sport and tribal fisheries. Impacts are assessed for each population in relation to critical and minimum abundance thresholds (MAT) as described by the Interior Columbia Technical Recovery Team (ICTRT 2007). Population designations for the Imnaha and Grande Ronde Basins are listed in Table 1, and are based upon an analysis of Chinook salmon life history traits, distribution, abundance, and productivity, and geographical and ecological characteristics of the landscape within the Snake River Spring/Summer Chinook Salmon ESU (McElhany et al. 2000). The abundance-based harvest rate schedule for Imnaha and Grande Ronde Basin fisheries to be shared by all fishing entities in the basin is described in Table 2. Harvest is not considered when hatchery run size does not exceed the number of adults identified for broodstock and supplementation needs as described by sliding scale management plans set for each population’s hatchery program. Surplus is generally defined as the adult hatchery run projection less hatchery adults needed for broodstock. This approach limits sport harvest during years when wild fish runs are below MAT and hatchery fish runs are of similar size. In addition, near the lower end of the harvest rate scale, fisheries are not implemented until the allowable hatchery fish harvest exceeds 20 fish due to potential to over harvest within a single week. Fishery impacts to listed Snake River spring/summer Chinook salmon are assessed on a collective basis (i.e., the sum of recreational and tribal fisheries) by NOAA fisheries. However, the coordination of impact amongst states and tribes is a key component of executing conservation-based fisheries in the Imnaha and Grande Ronde Basins. Co-managers within each basin have developed, and implement annually, an impact sharing agreement that is described in Table 3. Within each fishery scenario, this agreement provides tribal fisheries more of the natural-origin impacts to reflect the non-selective nature of traditional fishing techniques. Recreational fisheries are provided a larger portion of the hatchery harvest such that all available impacts (hatchery and natural collectively) are shared equally (Table 3). Recreational fisheries administered by the states limit harvest (retention) of spring/summer Chinook hatchery-origin salmon with a clipped adipose fin (as evidenced by a healed scar). All salmon with an intact adipose fin (natural-origin) must be released back to the water. Therefore, incidental mortality impacts occur from catch and release of unclipped Snake River spring/summer Chinook salmon in fisheries targeting adipose-clipped hatchery Chinook salmon, and/or from the illegal retention of unclipped fish. It is generally assumed throughout the Columbia River Basin that the mortality rate resulting from the catch and release of salmon in fisheries is 10%. However, for Lookingglass Creek comanagers, with concurrence from NOAA fisheries, assume a slightly lower rate of 7.5% (ODFW and WDFW 2012). As stated in the FMEP, fisheries are adjusted or terminated when the total ESA take limit identified in Table 2 and 3 has been reached. Therefore, once fisheries are initiated regular monitoring is required to ensure consistency with co-manager agreements and FMEP requirements. The objective of this LSRCP project was to conduct statistical creel surveys to determine spring Chinook and steelhead ESA impact levels, harvest and release rates, and to inform decisions regarding fishery status in the Imnaha and Grande Ronde Basins in 2014. In this report, we describe creel surveys conducted and estimates of angler effort, catch, and harvest. In addition we compare these estimates in relation to estimates of natural and hatchery-origin returns to each population to assess consistency with prescribed impacts under FMEP guidelines. Lower Snake River Compensation Plan (LSRCP) ODFW
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1808. [Article] Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2013 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), ...Citation Citation
- Title:
- Lower Snake River Compensation Plan; Oregon Spring Chinook Salmon Harvest Monitoring - 2013 Annual Progress Report
Abstract -- The Imnaha and Grande Ronde River spring Chinook hatchery programs are components of the Lower Snake River Compensation Plan (LSRCP), funded through the U.S. Fish and Wildlife Service (USFWS), developed to mitigate for wild fish production lost as a result of construction of four lower Snake River dams. Hatchery Chinook and steelhead smolts in the Snake River basin are produced at LSRCP hatcheries in Washington, Idaho and Oregon. Subsequent adult returns are meant to provide tribal and recreational (sport) fisheries and, in some cases, enhance natural spawner numbers. The Oregon Department of Fish and Wildlife initiated the Imnaha and Grande Ronde spring Chinook hatchery program in 1982 under the LSRCP. Subsequent program management has been coordinated between ODFW, Confederated Tribes of the Umatilla Indian Reservation (CTUIR) and Nez Perce Tribe (NPT). The Imnaha and Grande Ronde River hatchery programs are comprised of five components, each with smolt acclimation and adult collection facilities located on the Imnaha River, upper Grande Ronde River, Lookingglass and Catherine Creeks, and the Lostine River. The Lostine River program interacts with natural production within the broader Wallowa-Lostine population unit. Other hatchery program components are discrete to specific populations indicated. The Lookingglass Creek portion of the program focuses on reintroduction of spring Chinook to that stream and targets the release of 250,000 smolts originating from the Catherine Creek population. Each of the four remaining program components integrates natural-origin fish returning to each respective tributary into production. Smolt release goals, developed to meet LSRCP mitigation responsibilities, include 490,000 for the Imnaha, 250,000 for the Lostine and upper Grande Ronde rivers, and 150,000 for Catherine Creek. Fisheries that target returns to the Imnaha and Grande Ronde hatchery programs are guided by Fishery Management and Evaluation Plans (FMEP), approved by NOAA fisheries under limit 4 of the final 4(d) rule of the Endangered Species Act (ODFW 2011, ODFW and WDFW 2012). The objective of the FMEP is to provide recreational fishing opportunities and related benefits derived from harvest of Imnaha and Grande Ronde basin hatchery-origin spring Chinook salmon in Oregon and Washington in a manner that supports the continued survival and future recovery of natural-origin Chinook salmon. Each respective FMEP utilizes a management framework for harvest of adipose-clipped, hatchery-origin Snake River spring/summer Chinook salmon using abundance-based sliding scales to set annual fishery impacts. Fisheries are prescribed maximum impact rates for both direct and incidental mortality of natural-origin adult salmon in sport and tribal fisheries. Impacts are assessed for each population in relation to critical and minimum abundance thresholds (MAT) as described by the Interior Columbia Technical Recovery Team (ICTRT 2007). Population designations for the Imnaha and Grande Ronde Basins are listed in Table 1, and are based upon an analysis of Chinook salmon life history traits, distribution, abundance, and productivity, and geographical and ecological characteristics of the landscape within the Snake River Spring/Summer Chinook Salmon ESU (McElhany et al. 2000). The abundance-based harvest rate schedule for Imnaha and Grande Ronde Basin fisheries to be shared by all fishing entities in the basin is described in Table 2. Harvest is not considered when hatchery run size does not exceed the number of adults identified for broodstock and supplementation needs as described by sliding scale management plans set for each population’s hatchery program. Surplus is generally defined as adult hatchery run projection less hatchery adults needed for broodstock. This approach limits sport harvest during years when wild fish runs are below MAT and hatchery fish runs are of similar size. In addition, near the lower end of the harvest rate scale, fisheries are not implemented until allowable hatchery fish harvest exceeds 20 fish due to potential to over harvest within a single week. Fishery impacts to listed Snake River spring/summer Chinook salmon are assessed on a collective basis (i.e., the sum of recreational and tribal fisheries) by NOAA fisheries. However, the coordination of impact amongst states and tribes is a key component of executing conservation-based fisheries in the Imnaha and Grande Ronde Basins. Co-managers within each basin have developed, and implement annually, an impact sharing agreement that is described in Table 3. Within each fishery scenario, this agreement provides tribal fisheries more of the natural-origin impacts to reflect the non-selective nature of traditional fishing techniques. Recreational fisheries are provided more of the hatchery harvest such that all available impacts (hatchery and natural collectively) are shared equally (Table 3). Recreational fisheries administered by the states limit harvest (retention) of spring/summer Chinook hatchery-origin salmon with a clipped adipose fin (as evidenced by a healed scar). All salmon with an intact adipose fin (natural-origin) must be released back to the water. Therefore, incidental mortality impacts occur from catch and release of unclipped Snake River spring/summer Chinook salmon in fisheries targeting adipose-clipped hatchery Chinook salmon, and/or from the illegal retention of unclipped fish. It is generally assumed throughout the Columbia River Basin that the mortality rate resulting from the catch and release of salmon in fisheries is 10%. However, for Lookingglass Creek comanagers, with concurrence from NOAA fisheries, assume a slightly lower rate of 7.5% (ODFW and WDFW 2012). As stated in the FMEP, fisheries are adjusted or terminated when the total ESA take limit identified in Table 2 and 3 has been reached. Therefore, once fisheries are initiated regular monitoring is required to ensure consistency with co-manager agreements and FMEP requirements. The objective of this LSRCP project was to conduct statistical creel surveys determine spring Chinook and steelhead ESA impact levels, harvest and release rates, and to inform decisions regarding fishery status in the Imnaha and Grande Ronde Basins in 2013. In this report, we describe creel surveys conducted and estimates of angler effort, catch, and harvest. In addition we compare these estimates in relation to post-season preliminary estimates of natural and hatchery-origin returns to each population to assess consistency with prescribed impacts under FMEP guidelines. Lower Snake River Compensation Plan (LSRCP) ODFW
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1809. [Article] Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced ...Citation Citation
- Title:
- Recovery of Wild Coho Salmon In Salmon River Basin, 2008-2010 Report Number: OPSW-ODFW-2011-10
Abstract -- Hatcheries have been a centerpiece of salmon management in the Pacific Northwest for more than a century but recent evidence of adverse interactions between hatchery and naturally-produced salmon have resulted in substantial changes in many hatchery programs. In 2007 the Oregon Department of Fish and Wildlife terminated a 30-year artificial propagation program for coho salmon in the Salmon River basin after a status assessment concluded that wild population viability was threatened by hatchery effects on salmon productivity (Chilcote et al. 2005). Hatchery-reared coho comprised 50-100% of the naturally spawning population in recent years. Low productivity was reflected in a low spawner to recruit ratio, and life-stage specific survival was lower than that of nearby populations. The temporal distribution of adult spawning in the basin was truncated and peaked 1.5 months earlier relative to the pre-hatchery period and adjacent coastal populations. The cessation of hatchery releases into Salmon River not only removed the primary factor believed to limit productivity of the local population, it also constituted a rare management experiment to test whether a naturally-spawning population can recover from a prolonged period of low abundance after interactions with hatchery-produced coho salmon are eliminated. This report summarizes the results of coho population studies at Salmon River for the first three years after the hatchery program was discontinued. The study in Salmon River is timely because ecological interactions between hatchery and wild fish have been implicated in the reduced survival and decreased productivity of wild coho and other salmonid populations (Nickelson 2003, Buhle et al. 2009, Chilcote et al. 2011). Recent studies involving a diversity of salmonid species and watersheds have shown a negative relationship between hatchery spawner abundance and wild population productivity regardless of the duration of hatchery influence (Chilcote et al. 2011). Yet neither the mechanisms of these productivity declines nor their potential reversibility have been investigated. Recent management changes at Salmon River provide an opportunity to experimentally evaluate coho salmon survival and productivity following the elimination of a decades-long hatchery program. The results will provide new insights into the reversibility of hatchery effects and the rate, mechanisms, and trajectory of response by a naturally spawning coho salmon population. Hatchery programs have been shown to change the timing and distribution of naturally spawning adults, but ecological and genetic influences on the spatial structure and life history diversity of juvenile populations are poorly understood. Conventional understanding of the life history of juvenile coho has presumed a relatively fixed pattern of rearing and migration. However, recent studies have found much greater variation in juvenile life history and habitat-use patterns than previously expected (Miller and Sadro 2003, Koski 2009), including evidence that estuaries may play a prominent role in the life histories of some coho salmon populations. A recent study in the Salmon River basin found considerable diversity in the life histories of juvenile Chinook salmon, including extended rearing by fry and other subyearling migrants within the complex network of natural and restored estuarine wetlands (Bottom et al. 2005). Unfortunately, interpretation of juvenile life history variations at Salmon River was confounded by the Chinook hatchery program, which has concentrated spawning activity in the lower river near the hatchery and may directly influence juvenile migration and rearing patterns. Discontinuation of the coho hatchery program at Salmon River provides an opportunity to quantify changes in juvenile life history following the elimination of all hatchery-fish interactions with the naturally spawning population. Such responses may provide important insights into the mechanisms of hatchery influence on wild salmon productivity and population resilience. Our research integrates adult and juvenile life stages, examines linkages to physical habitat conditions in fresh water and the estuary, and describes variability between juvenile performance and adult returns. It also monitors the coho salmon population across habitat types and life history stages to identify population responses at a landscape scale. We will determine productivity and survival at each salmon life stage and monitor the response of the adult population following the cessation of the coho salmon hatchery program. From these indicators, we will determine the potential resiliency of the coho salmon population, and evaluate the biological benefits or tradeoffs of returning the ecosystem to natural salmon production. Our study design encompasses four population phases: (1) pre-hatchery conditions (Mullen 1979), (2) dominance by hatchery-reared spawners (2008), (3) first generation naturally produced juveniles (2009-2011), and (4) second generation naturally produced juveniles (starting in 2012). This research will validate assumptions about factors limiting coho recovery and determine whether recovery actions have been effective. Here, we report on findings from 2008-2010 to address four principal objectives: 1. Quantify life stage specific survival and recruits per spawner ratio of the coho salmon population before and after hatchery coho salmon are removed from Salmon River. 2. Assess whether the Salmon River coho population is limited by capacity and complexity of stream habitat. 3. Describe the diversity of juvenile and adult life histories of coho salmon in the Salmon River basin, and estimate the relative contributions of various juvenile life histories to adult returns. 4. Determine seasonal use of the Salmon River estuary and its tidally-inundated wetlands by juvenile coho salmon. The field sampling that supported the study on coho salmon also captured Chinook salmon and steelhead and cutthroat trout during routine sampling in the watershed and estuary. This report emphasizes coho salmon results, but also summarizes catch, distribution, and migration data for other salmonids to compare densities and abundances in freshwater and the estuary. Additional results for Chinook, steelhead, and cutthroat are presented in Appendix A. See Stein et al. (2011) for more detailed information on life history diversity, migration patterns, habitat use, and abundance of cutthroat trout.
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California's Central Valley agricultural landscapes provide several important wintering regions for Pacific Flyway sandhill crane (Grus canadensis) populations; however, the value of those regions is being ...
Citation Citation
- Title:
- Comparative wintering ecology of two subspecies of sandhill crane : informing conservation planning in the Sacramento-San Joaquin River Delta region of California
- Author:
- Ivey, Gary L.
California's Central Valley agricultural landscapes provide several important wintering regions for Pacific Flyway sandhill crane (Grus canadensis) populations; however, the value of those regions is being compromised by urban expansion, other developments, and conversions to incompatible crop types. Greater (G. c. tabida) and lesser sandhill cranes (G. c. canadensis) both have special conservation status in California; the greater is listed as threatened and the lesser as a bird species of conservation concern by the state. However, basic information about their wintering ecology has been lacking to design biologically sound conservation strategies to maintain their wintering habitats. My study of sandhill cranes focused on one major Central Valley wintering region, the Sacramento-San Joaquin River Delta (Delta). I compared daily movements and winter site fidelity between the two sandhill crane subspecies, evaluated the timing of crane arrival and departure from the region, assessed foraging habitat choices, measured abundance and distribution in the Delta, documented the characteristics of roost sites, and developed habitat conservation models and decision tools for managers to facilitate habitat conservation and management. Both crane subspecies showed strong fidelity to my Delta study area. Foraging flights from roost sites were shorter for greaters than lesser (1.2 ± 0.4 km vs. 3.1 ± 0.1 km, respectively) and consequently, mean size of 95% fixed kernel winter home ranges was an order of magnitude smaller for greaters (1.9 ± 0.4 km² vs.21.9 ± 1.9 km², respectively). The strong site fidelity of greaters to roost complexes within landscapes in the Delta indicates that conservation planning targeted at maintaining and managing for adequate food resources around traditional roost sites can be effective for meeting sandhill crane habitat needs, while the scale of conservation differs by subspecies. I recommend that conservation planning actions consider all habitats within 5 km of a crane roost as a sandhill crane conservation "ecosystem unit." This radius encompasses 95% and 69% of the flights from roosts to foraging location (commuting flights) made by greaters and lessers, respectively. For lessers, a conservation radius of 10 km would encompass 90% of the commuting flights. Management, mitigation, acquisition, easement, planning, and farm subsidy programs intended to benefit cranes will be most effective when applied at these scales. Within these radii, conservation and management of wintering habitats should include creating both new roost and feeding areas to ensure high chances of successful use. Sandhill cranes used major crops and habitat types available in the landscapes surrounding their roost sites and focused most of their foraging in grain crops. They generally avoided dry corn stubble, selected dry rice stubble early in the season, and rarely used dry wild rice stubble. Tilled fields were also usually avoided but were occasionally used shortly after tillage. Mulched corn ranked high in comparison to other corn treatments while mulched rice use was used similarly to dry rice stubble. Both subspecies often highly favored cropland habitats when they were initially flooded. Cranes were attracted to new plantings of pasture and winter wheat. One important difference between the subspecies was that lessers used alfalfa which was generally avoided by greaters. Dry corn stubble was avoided while dry rice stubble was favored early in winter. If wildlife managers want to encourage winter field use by cranes they could provide incentives for favorable practices such as production of grain crops, reduction or delaying tillage and flooding of grain fields, provision of irrigations to some crop types, and increasing the practice of mulching of corn stubble. Of the 69 crane night roosts I identified, 35 were flooded cropland sites and 34 were wetland sites. I found that both larger individual roost sites and larger complexes of roost sites supported larger peak numbers of cranes. Water depth used by roosting cranes averaged 10 cm (range 3-21 cm, mode 7 cm) and was similar between subspecies. Roosting cranes avoided sites that were regularly hunted or had high densities (i.e., > 1 blind/5 ha) of hunting blinds. Roost site design and management should consider providing and maintaining large roost complexes (100 - 1000 ha) ideally in close proximity (< 5 km) to other roost sites, with large individual sites (> 5 ha) of mostly level topography, dominated by shallow water (5-10 cm depths). The fact that cranes readily use undisturbed flooded cropland sites makes this a viable option for creation of roost habitat. Because hunting disturbance can limit crane use of roost sites I suggest these two uses should not be considered compatible. However, if the management objective of an area includes waterfowl hunting, limiting hunting at low blind densities (i.e., < 1 blind/60 ha) and restricting hunting to early morning may be viable options for creating a crane-compatible waterfowl hunt program. Radio-marked sandhill cranes arrived in the Delta beginning 3 October, most arrived in mid-October, and the last radio-marked sandhill crane arrived on 10 December. Departure dates ranged from 15 January to 13 March. Mean arrival and departure dates were similar between subspecies. From mid-December through early-February in 2007-2008, the Delta population ranged from 20,000 to 27,000 sandhill cranes. Abundance varied at the main roost sites during winter, likely because sandhill cranes responded to changes in water and foraging habitat conditions. Sandhill cranes used an area of approximately 1,500 km² for foraging. Estimated peak abundance in the Delta was more than half the total number counted on recent Pacific Flyway midwinter surveys, indicating the Delta region is a key area for efforts in conservation and recovery of wintering sandhill cranes in California. Based on arrival dates, flooding of sandhill crane roost sites should be staggered with some sites flooded in early September and most sites flooded by early October. Maintaining flooding of at least some roost sites through mid-March would provide essential roosting habitat until most birds have departed the Delta region on spring migration. Not all 5-km radius ecosystem units are equal in their value to greater sandhill cranes, and the relative foraging value of a particular parcel within an ecosystem unit depends on the numbers of cranes using the focal roost site, the habitat choices they make, and the probability that they will fly to a particular parcel. Additionally, some ecosystem units overlap, and in these overlap zones, the probability of crane use is higher, because of additive effects. To provide a tool to allow managers to further refine management plans, I developed a model which allows more specific focus of crane conservation, mitigation and habitat management, using what my study revealed about greater sandhill cranes. This model considers the abundance of greaters at individual roost sites and the probability that they would fly to a given location. Sites closer to roosts had a higher probability of crane use. I calculated the probability that greaters would fly to a parcel within concentric 1-km intervals as a product of the proportion of commuting flights of individuals that reached that interval, and the proportion of all commuting flights that reached that interval. Within crane ecosystem units, it is important to protect the existing habitat from further loss and optimize foraging conditions for cranes. I provide a decision matrix to assist with plans to enhance existing crane landscapes, create new crane habitat areas or mitigate habitat losses. This matrix provides a framework for decision-making regarding enhancing sandhill crane foraging and roost site habitats. Wildlife managers could employ a variety of tools to conserve and manage crane habitats, including fee title acquisitions, private conservation easements, and specific cropland management actions to maintain crane-compatible conditions and high food values for cranes (possibly including providing unharvested food plots). My study has demonstrated that most cranes use a relatively small landscape surrounding their traditional roost sites and that they favor certain crops and post-harvest crop management practices for foraging. However, we need a better understanding of the actual carrying capacity for cranes in these crane management zones to ensure that managers can maintain these sites for cranes in the future.