Introduction As the population of California continues to grow, new communities emerge and existing ones expand. Impervious surfaces, including roads, houses, and commercial buildings, are a hallmark of this urban expansion. These impervious surfaces have significant impacts on local watersheds. Impervious cover (IC) affects the hydrology, chemistry, and biotic integrity of aquatic ecosystems. Many of the effects are interrelated and can often be difficult to pinpoint and assess. Schueler (1997) described the impacts of increasing watershed IC on stream conditions as occurring in three primary stages: a) non-impacted streams when IC was less than 10%, b) impacted when IC was between 10 and 25%, and c) degraded waterways when IC exceeded 25%. Questions have been raised regarding the applicability of these thresholds to California's arid and semi-arid climates. Some studies suggest that the thresholds are actually lower in the arid Southwest (Coleman et al., 2005). Others suggest that total watershed IC is less relevant than connected IC or the IC within the riparian corridor, floodplain, or upstream portions of the watershed. Climate, geomorphology, and historical flow regimes of the watershed can also affect the threshold values. The validity of any threshold value is also a question that is under consideration. The literature reviewed in this annotated bibliography touches on these and other factors relevant to assessing the impacts of impervious cover on the aquatic ecosystem. The review is divided into four main sections as follows: Background/Purpose: The purpose of this paper is to document the abundance and distribution of the Jollyville Plateau salamander, and to identify its habitat requirements and factors that may regulate the abundance and distribution of the species. The Jollyville Plateau salamander is a lungless salamander whose range is limited to six small drainages on the Edwards Plateau, Texas. The species was first described in 2000 and status of its population is not well understood. Most of the range of the species is potentially threatened by impairment from urban development. Methods: Six sites known to provide habitat for salamanders were monitored for a two year period. Based on total impervious cover (TIA), sites were labeled as either developed (TIA>10%) or undeveloped (TIA<10%). Impervious cover was estimated from GIS maps of roads and buildings developed using 1997 aerial photos. Salamanders were surveyed each month and the habitat characteristics, including potential predators, were noted. The surface water chemistry was also sampled to determine temperature, pH, and dissolved oxygen. Results: …

Green sturgeon ( Acipenser medirostris) movement patterns and habitat use within the Rogue River, Oregon were evaluated using radio telemetry. Nineteen specimens ranging from 154 to 225 cm total length were caught by gill netting and tagged with radio transmitters during May July 2000. One tagged green sturgeon was verified as a female near spawning condition. Individual green sturgeons spent more than 6 months in fresh water and traveled as far as river kilometer (rkm) 39.5. Green sturgeon preferred specific holding sites within the Rogue River during summer and autumn months. These sites were typically deep ( > 5 m) low-gradient reaches or off-channel coves. Home ranges within holding sites were restricted. All tagged individuals emigrated from the system to the sea during the autumn and winter, when water temperatures dropped below 10 degreesC and flows increased. This species is extremely vulnerable to habitat alterations and overfishing because it spawns in only a few North American rivers and individuals reside within extremely small areas for extended periods of time.

1. Despite wide recognition of the need for catchment‐scale management to ensure the integrity of river ecosystems, the science and policy basis for joint management of land and water remains poorly understood. An interdisciplinary case study of a river basin in south‐eastern Michigan is presented.2. The River Raisin drains an area of 2776 km2, of which some 70% is agricultural land. The upper basin consists of till and outwash, and both topography and land use/cover are diverse. The lower basin consists of fine textured lake deposits, is of low relief, and land use is primarily agricultural.3. The River Raisin basin historically was a region of oak‐savannah and wetlands. It was deforested, drained and converted to farmland during the mid‐nineteenth century. Human population reached a plateau at about 1880, and then underwent a second period of growth after 1950, mainly in small urban areas. More recently, the amount of agricultural land has declined and forested land has increased, in accord with a general decline in farming activity.4. It could be suggested that the influence of land use on stream integrity is scale‐dependent. Instream habitat structure and organic matter inputs are determined primarily by local conditions such as vegetative cover at a site, whereas nutrient supply, sediment delivery, hydrology and channel characteristics are influenced by regional conditions, including landscape features and land use/cover at some distance upstream and lateral to stream sites.5. Sediment concentrations measured during low flows were higher in areas of greater agriculture. In a comparison of two subcatchments, sediment yields were up to ten times greater in the more agricultural location, in response to similar storm events. A distributed parameter model linked to a geographical information system predicted that an increase in forested land cover would result in dramatic declines in runoff and sediment and nutrient yields.6. Habitat quality and biotic integrity varied widely among individual stream sites in accord with patterns in land use/cover. Extent of agricultural land at the subcatchment scale was the best single predictor of local stream conditions. Local riparian vegetation was uncorrelated with overall land use and was a weak secondary predictor of habitat quality and biotic integrity.7. Investigation of the regulatory agencies involved in land and water management in the basin revealed a complex web of overlapping political jurisdictions. Most land‐use decision‐making occurs at the local level of township, city or village. Unfortunately, local decision‐making bodies typically lack the information and jurisdictional authority to influence up‐ and downstream events.

Length and age at maturity were determined for tilefish Lopholatilus chamaeleonticeps collected off the Georgia coast during the reproductive season. Fifty percent of the females were mature at a total length (TL) of 500 mm and an age of 6 years (the youngest female collected), whereas 50% of males were mature at 450 mm TL and 5 years of age (the youngest male collected); true sizes and ages of median maturity may be less. Fecundity estimates increased nonlinearly with tilefish weight, length, and age and ranged from approximately 0.85 × 106 to 8.5 × 106 eggs for fish ranging from 573 mm TL (2.0 kg, 8 years) to 899 mm TL (8.9 kg, 20 years), respectively. The relationship between fecundity (F) and length was: Log eF = (4.749 logeTL) - 16.508; r2= 0.93; N = 31. We observed disproportionately large numbers of females at smaller lengths and of males at larger lengths. This would be expected if protogynous hermaphroditism were common among tilefish in the South Atlantic Bight. Skewed sex ratios, howev...

Reproductive cycling and oocyte development were examined for female tilefish, Lopholatilus chamaeleonticeps Goode and Bean, captured in the South Atlantic Bight, U.S.A. A total of 752 female tilefish was collected during 15 sampling periods from May 1982 to December 1983. Reproductive cycling was quantified using four techniques: gross visual estimation of ovarian stages, histological examination of ovaries, follicle diameter measurements, and an ovarian index. The relative accuracies of these techniques also were evaluated. All four methods indicated that L. chamaeleonticeps was capable of spawning from March to June. Most spawning occurred between April and June. Ovarian development was positively correlated with the change in daylength. Follicular development was asynchronous, which is characteristic of multiple spawners. Folliculogenesis was similar to that in most oviparous teleosts.

1.1. Gonadal indices (i.e. GSI = gonadalwt/bodywt × 100) commonly are used to quantify reproductive condition in fishes. These indices may be inappropriate with specimens of different sizes. however, for gonActal growth often is allometric.2.2. A new gonadal index (relative gonadtal index, RGI) was developed to quantify the reproductive condition of animals independent of body size.3.3. The RGI is based on the underlying model W = αiSβi, where W is gonActal weight, S is body size (less gonadal weight if body weight is used), and α, and β, are parameters to be estimated for gonadal developmental stage i.4.4. Assuming that a multiplicative lognormal error is appropriate, parameter estimates for αi, and βi were obtained by linear least squares regression for the log-transformed model ln(W) = βi-ln(S) + ln(αi), where, in this form, βi is the slope and ln (αi) is the intercept.5.5. Only if estimates of βi, do not differ significantly among ovarian developmental stages, as in our case, can a pooled estimate of β be used to obtain the relative gonActal index, RGI = αi = W/Sβ.6.6. Applicability of the RGI was tested using ovaries of three ecologically distinct fish species. The RGI was found to be more appropriate than the gonosomatic index for all three species.

ADVERTISEMENT RETURN TO ISSUEArticleNEXTSelective Properties of High Flux Cellulose Acetate Membranes toward Ions Found in Natural WatersD. L. Erickson, Julius Glater, and J. W. McCutchanCite this: Ind. Eng. Chem. Prod. Res. Dev. 1966, 5, 3, 205–211Publication Date (Print):September 1, 1966Publication History Published online1 May 2002Published inissue 1 September 1966https://pubs.acs.org/doi/10.1021/i360019a001https://doi.org/10.1021/i360019a001research-articleACS PublicationsRequest reuse permissionsArticle Views90Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts