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At least 1,423 records · Page 79Linked to original sources
USGS1998

Sexual difference in polychlorinated biphenyl accumulation rates of walleye (Stizostedion vitreum)

Adult male walleye (Stizostedion vitreum) exhibited significantly higher polychlorinated biphenyl (PCB) concentrations than similarly aged female walleye from Saginaw Bay (Lake Huron). To explain this difference, we tested the following three hypotheses: (i) females showed a considerably greater reduction in PCB concentration immediately following spawning than males, (ii) females grew at a faster rate and therefore exhibited lower PCB concentrations than males, and (iii) males spent more time in the Saginaw River system than females, and therefore received a greater exposure to PCBs. The first hypothesis was tested by comparing PCB concentration in gonadal tissue with whole-body concentration, the second hypothesis was tested via bioenergetics modeling, and we used mark-recapture data from the Saginaw Bay walleye fishery to address the third hypothesis. The only plausible explanation for the observed difference in PCB accumulation rate was that males spent substantially more time in the highly contaminated Saginaw River system than females, and therefore were exposed to greater environmental concentrations of PCBs. Based on the results of our study, we strongly recommend a stratified random sampling design for monitoring PCB concentration in Saginaw Bay walleye, with fixed numbers of females and males sampled each year.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1995

Genetic contribution of hatchery fish to walleye stocks in Saginaw Bay, Michigan

Stocks of walleye ( Stizostedion vitreum ) were severely depressed in Saginaw Bay in the 1970s. In 1979, the Michigan Department of Natural Resources began intensive stocking of walleye fingerlings to bolster fish populations. Subsequent to stocking, the walleye fishery has recovered. The study objective was to determine if recovery was due to the stocking program or natural reproduction. Inherent genetic differences between hatchery fish and endemic walleyes were used to determine the effect and contribution of hatchery fish to Saginaw Bay.

Michigan↗
USGS1997

Fossil zooplankton and the historical status of westslope cutthroat trout in a headwater lake of Glacier National Park, Montana

Surviving pure-strain populations of westslope cutthroat trout Oncorhynchus clarki lewisi in headwater lakes of Glacier National Park could play an important role in the managed recovery of regional cutthroat trout fisheries. However, uncertainty exists about whether native trout could have naturally invaded several park lakes where they now occur. This study used paleolimnological techniques to address the question of whether the population of native trout in Avalanche Lake is indigenous or became established through an undocumented introduction. The validity of using fossil diapause eggs (ephippia) of the fish-sensitive cladocerans Daphnia spp. as indicators for the historical presence of zooplanktivorous fish was tested with a survey of live zooplankton and corresponding surface-sediment fossil assemblages in eight Glacier Park lakes with or without trout. Analysis of a sediment core from Avalanche Lake dated by lead radioisotopes, historical wildfires, and a flood allowed reconstruction of zooplankton dynamics from about 1700 A.D. to the present. Fossil Daphnia ephippia were rare or absent in Avalanche Lake sediments deposited before 1910, suggesting intense zooplanktivory due to sustained presence of an indigenous population of native cutthroat trout. Fossil evidence for larger Daphnia populations in the 1930s and early 1940s revealed a temporary disturbance of the lake's normal food web interactions during which zooplanktivory was significantly reduced. This disturbance may have resulted from a collapse of the native trout population caused indirectly by failed attempts between 1915 and 1943 to stock Avalanche Lake with Yellowstone cutthroat trout O. clarki bouvieri.

Transactions of the American Fisheries Society↗
USGS2002

Capture locations and growth rates of Atlantic sturgeon in the Chesapeake Bay

Little information exists on temporal and spatial distributions of wild and hatchery-reared Atlantic sturgeon Acipenser oxyrinchus oxyrinchus in the Chesapeake Bay. Approximately 3,300 hatchery-reared Atlantic sturgeon comprised of two size groups were released into the Nanticoke River, a tributary of the Chesapeake Bay, on 8 July 1996. During January 1996-May 2000, 1099 Atlantic sturgeon were captured incidentally (i.e., bycatch) by commercial watermen in the Chesapeake Bay, including 420 hatchery-reared individuals. Wild and hatchery-reared Atlantic sturgeon were captured primarily in pound nets and gill nets. Biologists tagged each fish and recorded weight, length, and location of capture. Although two adults greater than 2000 mm fork length (FL) were captured in Maryland waters, wild sturgeon were primarily juveniles from Maryland and Virginia waters (415 and 259 individuals below 1000 mm FL, respectively). A growth rate of 0.565 mm/d (N = 15, SE = 0.081) was estimated for wild individuals (487-944 mm TL at release) at liberty from 30 to 622 d. The average growth of the group of hatchery-reared Atlantic sturgeon raised at 10??C exceeded that of the group raised at 17??C. Our distributional data based on capture locations are biased by fishery dependence and gear selectivity. These data are informative to managers, however, because commercial effort is widely distributed in the Chesapeake Bay, and little distributional data were available before this study.

American Fisheries Society Symposium↗
USGS2002

Whirling disease among snake river cutthroat trout in two spring streams in Wyoming

We assessed endemic age-0 cutthroat trout Oncorhynchus clarki for evidence of pathology associated with Myxobolus cerebralis in two streams formed by springs in western Wyoming. We hypothesized that the location of spawning sites in spring streams would affect the extent of exposure of cutthroat trout fry to M. cerebralis triactinomyxons (tams), occurrence of the parasite in their bodies, and clinical signs of whirling disease. The spring streams were warm relative to nearby streams flowing from the mountains or spawning and emergence of fry was early compared with fish in mountain streams. Tams were abundant early in the summer and clinical signs of whirling disease among age-0 fish were seen as early as mid-June in one stream. There were high densities of tams in one stream, and densities declined with upstream progression from May through July, whereas in the other stream, low densities of tams were observed in the downstream portion early in the summer, and they were not detected in July and August. Age-0 cutthroat trout were abundant; clinical signs of whirling disease were evident, and histological evidence of whirling disease was common in the stream where tams were abundant. Low densities of age-0 cutthroat trout and no clinical signs of whirling disease were observed in the stream where tams were not abundant. Among sentinel fish in the stream with abundant tams, we found extensive occurrence of M. cerebralis, with many fish showing clinical signs and histological evidence of pathology associated with M. cerebralis. The proportion of sentinel fish with clinical and histological signs of whirling disease decreased with upstream progression. In the stream with low tam, densities sentinel fish became infected with M. cerebralis, but there were essentially no clinical signs or histological indications of whirling disease. ?? 2002 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2002

A reservoir landscape for age-0 largemouth bass

Landscape ecology is concerned with how ecological processes are affected by spatial patterns. Identification of heterogeneity in littoral zones has expanded the conceptual framework of aquatic landscapes. Long-term study of a reservoir largemouth bass population indicated that the amount and arrangement of habitat regulated the population processes. The distribution of age-0 largemouth bass was quantified in relation to littoral habitat and relations between landscape features and population parameters on scales from embayment to microhabitat were determined. At the embayment scale, shoreline slope and amount of gravel substratum predicted fivefold variability in abundance among four reservoir embayments. Within an embayment, these habitat features explained between 37 and 88 percent of variation in shoreline distribution of age-0 largemouth bass. At the microhabitat scale, age-0 largemouth bass exhibited patchy distributions in relation to gravel substratum at 40 percent of sites. These results indicate that the landscape scale domain for young largemouth bass is large; whereas, specific patterns explained processes across multiple scales. Distributions of age-0 largemouth bass in relation to habitat, however, were apparent on a fine scale (10 m) and these data, coupled with limited movement behavior of young largemouth bass, indicate that the ecological neighborhood of this life stage is small. Our data also suggested that some habitats may be source habitats because embayments with hypothesized higher source/sink ratios were more productive. Although patch arrangement critical to young largemouth bass ecology was not quantified, it was apparent that embayments with more complex habitats likely provided the extent of the landscape for age-0 largemouth bass in Jordan Lake. Identification of scale of patchiness (of fish distributions and habitats) for this life stage will assist in making inferences regarding complex ecological processes that can affect year-class productivity on multiple scales. ?? 2002 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2002

A simulation study of factors controlling white sturgeon recruitment in the Snake River

Five of the nine populations of white sturgeon Acipenser transmontanus, located between dams on the Middle Snake River, have declined from historical levels and are now at risk of extinction. One step towards more effectively protecting and managing these nine populations is ranking factors that influence recruitment in each of these river segments. We developed a model to suggest which of seven mechanistic factors contribute most to lost recruitment in each river segment: (1) temperature-related mortality during incubation, (2) flow-related mortality during incubation, (3) downstream export of larvae, (4) limitation of juvenile and adult habitat, (5) mortality of all ages during summer episodes of poor water quality in reservoirs, (6) entrainment mortality of juveniles and adults, and (7) angling mortality. We simulated recruitment with, and without, each of the seven factors, over a typical series of hydrologic years. We found a hierarchical pattern of limitation. In the first tier, river segments with severe water quality problems grouped together. Poor water quality during summer had a strong negative effect on recruitment in the river segments between Swan Falls Dam and Hell's Canyon Dam. In the second tier, river segments with better water quality divided into short river segments and longer river segments. Populations in short river segments were limited by larval export. Populations in longer river segments tended to be less strongly limited by any one factor. We also found that downstream effects could be important, suggesting that linked populations cannot be viewed in isolation. In two cases, the effects of a factor on an upstream population had a significant influence on its downstream neighbors. ?? 2002 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2002

Characterization of annual reproductive cycles for pond-reared Florida largemouth bass Micropterus salmoides floridanus

The annual reproductive cycle of hatchery-raised largemouth bass (Florida subspecies Micropterus salmoides floridanus) was characterized over a one-year period. Largemouth bass have a distinct annual reproductive cycle with a spring spawning season (approximately between mid-January and mid-June). Cycle characterization focused on an evaluation of gonadal development and plasma concentrations of several sex steroids and vitellogenin (VTG). Adult largemouth bass (n = 20: 10 females and 10 males) were collected monthly from hatchery ponds for one full calendar year. Plasma samples were analyzed for estradiol-17?? (E2), 11-ketotestosterone (11-KT), testosterone (T), progesterone (P), and VTG. Gonadal tissues were weighed to calculate gonadosomatic index (GSI) and evaluated histologically to characterize reproductive stage. In both sexes, GSI began to increase in November, and peaked in February-March. Increases in gonad weights were correlated with maturation of gonads as evidenced by histological evaluations. Bass exhibited seasonal changes in plasma sex steroids and VTG. In males, 11-KT was the only sex steroid that showed strong seasonality, with highest values in February. In females, although E2 and T concentrations followed a similar annual cycle, with highest and lowest values in February and August, respectively, the strongest pattern was observed with E2. 11-KT concentrations were less variable across months, and values were about half of those observed in males. In females, P peaked two months after E2, with high values still in May and June and decreased thereafter, and VTG began to increase in October, but peaked a month prior to the observed peaked in E2. VTG was also detected in males but at concentrations that were about 1/12 that of females, and no seasonal pattern was evident. This study is the first to fully characterize the seasonal endocrine cycle for largemouth bass. These data will be useful when conducting reproductive evaluations of free-ranging populations of largemouth bass and for assessing potential reproductive effects due to environmental contaminants in this species. ?? 2002 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2003

Status of Alabama shad and skipjack herring in Gulf of Mexico drainages

Gulf of Mexico drainages are inhabited by two alosine species, the anadromous Alabama shad Alosa alabamae and the skipjack herring A. chrysochloris. Although their distributions are reasonably well documented, the life history and ecology of both species has been incompletely investigated. Infrequent literature references suggest populations of both species have been adversely affected by river management activities throughout parts of their ranges. This purpose of this paper is to summarize available information concerning past and present distributions, population characteristics, spawning and fecundity, age and growth, and population trends of both species as well as threats to the species. Areas of research are suggested to maintain and possibly recover existing populations. ?? 2003 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2003

Downstream movement of mature eels in a hydroelectric reservoir in New Zealand

This study investigates the behavior of migrant eels as they approached the Patea hydroelectric dam on the West Coast of the North Island, New Zealand. Seventeen mature migrant eels (870-1,240 mm; 2,000-6,380 g) were implanted with coded acoustic transmitters and released. Their movements in the reservoir were monitored for 14 months with stationary data logging and manual tracking receivers. The downstream migration of sexually maturing eels was found to occur mainly at night, usually during, or immediately after, rainfall events. Eels tended to travel at the surface, within the upper 4 m of the water column, at speeds ranging from 16 to 89 cm/s. Upon reaching the headrace, eels typically spent time searching, presumably for an unobstructed downstream route. In order to aid downstream passage of eels at the Patea Dam, power station operators began spillway opening trials during peak migration periods. Although this allowed some migrant eels to safely pass over the dam, information on the relative effectiveness and cost of this method over other possible mitigation methods is still required. ?? Copyright by the American Fisheries Society 2003.

American Fisheries Society Symposium↗
USGS2004

Effect of outflow on spring and summertime distribution and abundance of larval and juvenile fishes in the upper San Francisco Estuary

We analyzed data on spring and summertime larval and juvenile fish distribution and abundance in the upper San Francisco Estuary (SFE), California between 1995 and 2001. The upper SFE includes the tidal freshwater areas of the Sacramento-San Joaquin Delta downstream to the euryhaline environment of San Pablo Bay. The sampling period included years with a variety of outflow conditions. Fifty taxa were collected using a larval tow net. Two common native species, delta smelt Hypomesus transpacifucus and longfin smelt Spirinchus thaleichthys, and four common alien taxa, striped bass Morone saxatilis, threadfin shad Dorosoma petenense, gobies of the genus Tridentiger, and yellowfin goby Acanthogobins flavimanus, were selected for detailed analysis. Outflow conditions had a strong influence on the geographic distribution of most of the species, but distribution with respect to the 2 psu isohaline (X2) was not affected. The distribution patterns of delta smelt, longfin smelt, and striped bass were consistent with larvae moving from upstream freshwater spawning areas to down-stream estuarine rearing areas. There were no obvious relationships of outflow with annual abundance indices. Our results support the idea of using X2 as an organizing principle in understanding the ecology of larval fishes in the upper SFE. Additional years of sampling will likely lead to additional insights into the early life history of upper SFE fishes. ?? Copyright by the American Fisheries Society 2004.

American Fisheries Society Symposium↗
USGS2005

Fish assemblage responses to urban intensity gradients in contrasting metropolitan areas: Birmingham, Alabama and Boston, Massachusetts

We examined fish assemblage responses to urban intensify gradients in two contrasting metropolitan areas: Birmingham, Alabama (BIR) and Boston, Massachusetts (BOS). Urbanization was quantified by using an urban intensity index (UII) that included multiple stream buffers and basin land uses, human population density, and road density variables. We evaluated fish assemblage responses by using species richness metrics and detrended correspondence analyses (DCA). Fish species richness metrics included total fish species richness, and percentages of endemic species richness, alien species, and fluvial specialist species. Fish species richness decreased significantly with increasing urbanization in BIR (r = -0.82, P = 0.001) and BOS (r = -0.48, P = 0.008). Percentages of endemic species richness decreased significantly with increasing urbanization only in BIR (r = - 0.71, P = 0.001), whereas percentages of fluvial specialist species decreased significantly with increasing urbanization only in BOS (r = -0.56, P = 0.002). Our DCA results for BIR indicate that highly urbanized fish assemblages are composed primarily of largescale stoneroller Campostoma oligolepis, largemouth bass Micropterus salmoides, and creek chub Semotilus atromaculatus, whereas the highly urbanized fish assemblages in BOS are dominated by yellow perch Perca flavescens, bluegill Lefomis macrochirus, yellow bullhead Ameiurus natalis, largemouth bass, pumpkinseed L. gibbosus, brown bullhead A. nebulosus, and redfin pickerel Esox americanus. Differences in fish assemblage responses to urbanization between the two areas appear to be related to differences in nutrient enrichment, habitat alterations, and invasive species. Because species richness can increase or decrease with increasing urbanization, a general response model is not applicable. Instead, response models based on species' life histories, behavior, and autecologies offer greater potential for understanding fish assemblage responses to urbanization. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Status and conservation of the fish fauna of the Alabama River system

The Alabama River system, comprising the Alabama, Coosa, and Tallapoosa subsystems, forms the eastern portion of the Mobile River drainage. Physiographic diversity and geologic history have fostered development in the Alabama River system of globally significant levels of aquatic faunal diversity and endemism. At least 184 fishes are native to the system, including at least 33 endemic species. During the past century, dam construction for hydropower generation and navigation resulted in 16 reservoirs that inundate 44% of the length of the Alabama River system main stems. This extensive physical and hydrologic alteration has affected the fish fauna in three major ways. Diadromous and migratory species have declined precipitously. Fish assemblages persisting downstream from large main-stem dams have been simplified by loss of species unable to cope with altered flow and water quality regimes. Fish populations persisting in the headwaters and in tributaries to the mainstem reservoirs are now isolated and subjected to effects of physical and chemical habitat degradation. Ten fishes in the Alabama River system (including seven endemic species) are federally listed as threatened or endangered. Regional experts consider at least 28 additional species to be vulnerable, threatened, or endangered with extinction. Conserving the Alabama River system fish fauna will require innovative dam management, protection of streams from effects of urbanization and water supply development, and control of alien species dispersal. Failure to manage aggressively for integrity of remaining unimpounded portions of the Alabama River system will result in reduced quality of natural resources for future generations, continued assemblage simplification, and species extinctions. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Effects of landscape change on fish assemblage structure in a rapidly growing metropolitan area in North Carolina, USA

We evaluated a comprehensive set of natural and land-use attributes that represent the major facets of urban development at fish monitoring sites in the rapidly growing Raleigh-Durham, North Carolina metropolitan area. We used principal component and correlation analysis to obtain a nonredundant subset of variables that extracted most variation in the complete set. With this subset of variables, we assessed the effect of urban growth on fish assemblage structure. We evaluated variation in fish assemblage structure with nonmetric multidimensional scaling (NMDS). We used correlation analysis to identify the most important environmental and landscape variables associated with significant NMDS axes. The second NMDS axis is related to many indices of land-use/land-cover change and habitat. Significant correlations with proportion of largest forest patch to total patch size (r = -0.460, P < 0.01), diversity of patch types (r = 0.554, P < 0.001), and population density (r = 0.385, P < 0.05) helped identify NMDS axis 2 as a disturbance gradient. Positive and negative correlations between the abundance of redbreast sunfish Lepomis auritus and bluehead chub Nocomis leptocephalus, respectively, and NMDS axis 2 also were evident. The North Carolina index of biotic integrity and many of its component metrics were highly correlated with urbanization. These results indicate that aquatic ecosystem integrity would be optimized by a comprehensive integrated management strategy that includes the preservation of landscape function by maximizing the conservation of contiguous tracts of forested lands and vegetative cover in watersheds. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Effects of urbanization on benthic macroinvertebrate assemblages in contrasting environmental settings: Boston, Massachusetts; Birmingham, Alabama; and Salt Lake City, Utah

Responses of invertebrate assemblages along gradients of urban intensity were examined in three metropolitan areas with contrasting climates and topography (Boston, Massachusetts; Birmingham, Alabama; Salt Lake City, Utah). Urban gradients were defined using an urban intensity index (UII) derived from basin-scale population, infrastructure, land-use, land-cover, and socioeconomic characteristics. Responses based on assemblage metrics, indices of biotic integrity (B-IBI), and ordinations were readily detected in all three urban areas and many responses could be accurately predicted simply using regional UIIs. Responses to UII were linear and did not indicate any initial resistance to urbanization. Richness metrics were better indicators of urbanization than were density metrics. Metrics that were good indicators were specific to each study except for a richness-based tolerance metric (TOLr) and one B-IBI. Tolerances to urbanization were derived for 205 taxa. These tolerances differed among studies and with published tolerance values, but provided similar characterizations of site conditions. Basin-scale land-use changes were the most important variables for explaining invertebrate responses to urbanization. Some chemical and instream physical habitat variables were important in individual studies, but not among studies. Optimizing the study design to detect basin-scale effects may have reduced the ability to detect local-scale effects. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Relationships of field habitat measurements, visual habitat indices, and land cover to benthic macroinvertebrates in urbanized streams of the Santa Clara Valley, California

We evaluated several approaches for measuring natural and anthropogenic habitat characteristics to predict benthic macroinvertebrate assemblages over a range of urban intensity at 85 stream sites in the Santa Clara Valley, California. Land cover was summarized as percentage urban land cover and impervious area within upstream buffers and the upstream subwatersheds. Field measurements characterized water chemistry, channel slope, sediment, and riparian canopy. In . addition to applying the visual-based habitat assessment in U.S. Environmental Protection Agency's rapid bioassessment protocol, we developed a simplified urban habitat assessment index based on turbidity, fine sediment deposition, riparian condition, and channel modification. Natural and anthropogenic habitat variables covaried along longitudinal stream gradients and were highly correlated with elevation. At the scale of the entire watershed, benthic macroinvertebrate measures were equally correlated with variables expressing natural gradients and urbanization effects. When natural gradients were reduced by partitioning sites into ecoregion subsection groupings, habitat variables most highly correlated with macroinvertebrate measures differed between upland and valley floor site groups. Among the valley floor sites, channel slope and physical modification of channel and riparian habitats appeared more important than upstream land cover or water quality in determining macroinvertebrate richness and ordination scores. Among upland sites, effects of upstream reservoir releases on habitat quality appeared important. Rapid habitat evaluation methods appeared to be an effective method for describing habitat features important to benthic macroinvertebrates when adapted for the region and the disturbance of interest. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

A legacy of change: The lower Colorado River, Arizona-California-Nevada, USA, and Sonora-Baja California Norte, Mexico

The lower Colorado is among the most regulated rivers in the world. It ranks as the fifth largest river in volume in the coterminous United States, but its flow is fully allocated and no longer reaches the sea. Lower basin reservoirs flood nearly one third of the river channel and store 2 years of annual flow. Diverted water irrigates 1.5 million ha of cropland and provides water for industry and domestic use by 22 million people in the southwestern United States and northern Mexico. The native fish community of the lower Colorado River was among the most unique in the world, and the main stem was home to nine freshwater species, all of which were endemic to the basin. Today, five are extirpated, seven are federally endangered, and three are being reintroduced through stocking. Decline of the native fauna is attributed to predation by nonnative fishes and physical habitat degradation. Nearly 80 alien species have been introduced, and more than 20 now are common. These nonnative species thrived in modified habitats, where they largely eliminated the native kinds. As a result, the lower Colorado River has the dubious distinction of being among the few major rivers of the world with an entirely introduced fish fauna. ?? 2005 by the American Fisheries Society.

American Fisheries Society Symposium↗
USGS2005

Fish assemblage structure in an Oklahoma Ozark stream before and after rainbow trout introduction

Rainbow trout Oncorhynchus mykiss have been widely stocked throughout the United States as a popular sport fish. Our study was initiated to evaluate potential effects of rainbow trout introduction on native fishes to inform future decisions about trout stocking in northeastern Oklahoma streams. We sampled fish assemblages in pools, glides, and riffles in Brush Creek, Delaware County, Oklahoma, from February 2000 to September 2002, and experimentally stocked rainbow trout into the stream from November 2000 to March 2001 and November 2001 to March 2002. We used a combination of multivariate analyses to evaluate seasonal and habitat effects on native fish assemblages and to compare assemblage structure between prestocking, the first year of stocking, and the second year of stocking. Mesohabitat type significantly affected assemblage structure among years, whereas we did not detect an effect of season. We did not detect differences in assemblage structure among years in glide or riffle habitats. Native fish assemblage structure in pool habitats before rainbow trout introduction differed from assemblage structure in both the first and second year of stocking. Declines in seven species, including two native game fish (smallmouth bass Micropterus dolomieu and bluegill Lepomis machrochirus), contributed to assemblage dissimilarity in pool habitats between prestocking conditions and the second year of stocking. Our results indicate that stocking rainbow trout may cause local disruption in assemblage structure in pool habitats. ?? 2004 by the American Fisheries Society.

American Fisheries Society Symposium↗