THE INFLUENCE OF SPRING AND FALL TEMPERATURES ON THE AVOIDANCE RESPONSE OF JUVENILE ATLANTIC MENHADEN,BREVOORTIA TYRANNUS,EXPOSED TO SIMULTANEOUS CHLORINE-δT CONDITIONS1

ABSTRACT: The avoidance response of groups of juvenile Atlantic menhaden, Brevoortia tyrannus, was evaluated by exposing test species to a range of simultaneous total residual chlorine (TRC) (0.00, 0.05, 0.10, and 0.15 mg/L) and elevated temperature (0, 2, 4, and 6°C) conditions simulating power plant discharges. This species was tested at both 15 and 20°C to determine possible effects of acclimation temperature on the avoidance response. These temperatures were selected to represent spring or fall thermal conditions when most East Coast power plant facilities initiate power plant chlorination in the spring or terminate the use of this biocide in the fall. An unbalanced 3-factor factorial design was used to develop response surface avoidance models at 15 and 20°C. The model developed at 15°C showed: (1) an increase in avoidance occurred at all δT conditions as TRC increased from 0.00 to 0.05 mg/L; (2) a greater degree of avoidance occured at TRC concentrations above 0.05 mg/L at all δT conditions; and (3) TRC was the most important term inflencing avoidance. The model for Atlantic menhaden at 20°C showed: 1) avoidance increased with increasing TRC concentration at each δT condition; (2) avoidance did not necessarily increase with increasing δT's at each TRC concentration; (3) greatest avoidance occured at 0°C δT and 0.15 mg/L TRC; and (4) TRC was the most important term influencing avoidance. There was a significant difference (p < 0.00001) between avoidance models at 15 and 20°C. However, when extreme conditions of 0.15 mg/L TRC and 0–6°δT were compared, the degree of avoidance responses (percent time in control area) was similar.     

REVIEW AND ANALYSIS OF METHODS FOR QUANTIFYING INSTREAM FLOW REQUIREMENTS1

ABSTRACT: Present guidelines for selecting a method to determine instream flow requirements and evaluating the validity of the results from a particular method are insufficient. This paper contributes to the efforts of researchers to develop a guide and critique for instream flow methods. A review of instreani flow methods and recommendations for their application is supplemented by a summary of a comparison of four independent analyses. The four analyses: the Physical Habitat Simulation System approach of the Instream Flow Incremental Methodology by the U.S. Fish and Wildlife Service, the Montana Method by Tennant, and two methods by Orsborn (Maximum Spawning Area Flow and Maximum Spawning Area) represent resource intensive and simplistic data collection and analysis methods. Each analysis was used to independently determine flows to support spawning by chinook salmon (Oncorhynchus tshawytscha) in Willow Creek, Alaska. Results of these analyses indicate that each method can be used independently or collectively to generate instream flow recommendations, if calibrated to the site or area studied. Once adjusted to the species and basin of interest, methods similar to the Montana and two Orsborn methods should be used to determine flow recommendations for areas where competition for water is minimal. The Instream Flow Incremental Methodology or similar methods should be applied when competition for water is keen or when detailed evaluations of the responses of species/life phases to flow variations are required.     

BEHAVIORAL RESPONSES TO TWO ESTUARINE FISH SPECIES SUBJECTED TO BIS (tri-n-butyltin) OXIDE1

ABSTRACT: The objective of this investigation was to evaluate the avoidance responses of juvenile striped bass, Morone saxatilis and Atlantic menhaden, Brevoortia tyrannus to bis (tri-n-butyltin) oxide. An avoidance responses was exhibited by striped bass at a total organic tin concentration of 24.9 μg/L. Atlantic menhaden exhibited avoidance to total organic tin concentrations of 5.5 μg/L and greater. Atlantic menhaden are generally more sensitive to toxicants than striped bass; therefore, avoidance responses reported in this study are not surprising. It is highly likely that the concentrations of total organic tin that were avoided by the test species in this study were much higher than expected environmental concentrations. Ecologically significant hazards may occur due to potential effects that unperceived or non-avoided organotin concentrations may have on behavioral responses mediated by chemosensory systems.     

Local knowledge and training towards management

The urgency of managing marine resources is based on the fact that half of the world stocks are fully exploited, excluding those stocks that are already depleted. Artisanal fisheries in Brazil, both inland and coastal, are responsible for about half of the country’s catches. Therefore, management of local artisanal fisheries is a necessity that provides an additional benefit, considering the observation that decentralization and the use of local ecological knowledge (LEK) in management have given better results than centralized, top-down management. In this study, a third system of knowledge–based on practice and training–is built from the local and scientific systems of knowledge, and a method to accomplish practical steps in local management is shown. Four elements are considered for the process of linking systems towards management: (1) an understanding of the natural environment of the fishery and on the use of natural resources by locals; (2) the knowledge of the marine area used by fishers, i.e., location of fishing spots for each species; (3) the understanding of fisher behavior, e.g., using tools from optimal foraging theory; and (4) the knowledge fishers have of the biology and ecology of species and their LEK, based on studies of the ethnobiology, ethnoecology, and ethnotaxonomy of fish. Considering the availability of publications on topics 1 and 2, illustrative cases are shown using optimal foraging models in Itaipu Beach, Rio de Janeiro and São Paulo Bagre, Cananéia, São Paulo, and using common snook, Centropomus undecimalis, as an example for a target species. Finally, local programs including training courses using both scientific and local knowledge are proposed within coastal artisanal fisheries.     

Artisanal fishers’ ethnobotany: from plant diversity use to agrobiodiversity management

Artisanal fishers interact with plants in many ways, and with different intensities. In spite of being characterized by fisheries, Caiçaras use plants with varied degrees of management, since the less intensive management actions, extraction of forest products, until intensively management actions through the cultivation of the agrobiodiversity. This study presents the results of different research projects and includes the North and the South regions of São Paulo state coast. The objective is to characterize the diversity of extracted and cultivated species by traditional fishers at Southeastern region of Brazilian Atlantic forest. Ethnobotanical surveys revealed a high diversity of plants known and used, ranging up to a richness of 272 species known in two communities for the South coast, most of them being native. However, depending on the management intensity, this diversity can be rather particularized: we found 68 varieties of cassava (Manihot esculenta Crantz) at North region and 58 varieties at the South region, with exclusive vernacular names. Through an ethnobotanical perspective, we compare and discuss the different dynamic systems underlying the relationships between fishers and plants. The diversity of cultivated plants is analyzed in depth, focusing on the historical importance of agriculture among people who are currently characterized as fishers. A schematic model is proposed to explain the dynamic systems operating in the relationships between fishers and plants.     

A model of the emergence of infectious pancreatic necrosis virus in Scottish salmon farms 1996–2003

Infectious pancreatic necrosis virus (IPNV) is an increasingly common pathogen in farmed Scottish Atlantic salmon; over 80% of marine sites are now infected, although most do not suffer clinical disease. The increasing prevalence of this pathogen in farms over the period 1996–2003 is modelled using a simple susceptible–infected (SI) epidemic model. Because salmon production approximately doubled over this period, population-dependent and -independent transmission models are compared. The model generates mean R₀ (increase ratio) of 1.41 in fresh and 1.45 in marine water farms at the national level; higher values apply with time under population-dependent transmission (1.58, freshwater, 1.80 marine by 2003). Regional differences in R₀ are mostly moderate, indicating similar regional processes in spite of substantial difference in prevalence. Prevalence of IPNV for marine sites was further increased by the use of smolts (young salmon) from multiple freshwater sources. The model suggests that prevalence is entering dynamic equilibrium and will stabilise or only increase slowly as population increases. Cutting freshwater transmission is the most effective single strategy at reducing IPNV prevalence, but a combination of strategies (including reducing the number of sources of smolts) is better and indeed is required for eradication. Eradication would require cuts in transmission of at least 30–45% and this is unlikely to be practicable.     

Refining Biodiversity Conservation Priorities

Abstract:  Although there is widespread agreement about conservation priorities at large scales (i.e., biodiversity hotspots), their boundaries remain too coarse for setting practical conservation goals. Refining hotspot conservation means identifying specific locations (individual habitat patches) of realistic size and scale for managers to protect and politicians to support. Because hotspots have lost most of their original habitat, species endemic to them rely on what remains. The issue now becomes identifying where this habitat is and these species are. We accomplished this by using straightforward remote sensing and GIS techniques, identifying specific locations in Brazil's Atlantic Forest hotspot important for bird conservation. Our method requires a regional map of current forest cover, so we explored six popular products for mapping and quantifying forest: MODIS continuous fields and a MODIS land cover (preclassified products), AVHRR, SPOT VGT, MODIS (satellite images), and a GeoCover Landsat thematic mapper mosaic (jpg). We compared subsets of these forest covers against a forest map based on a Landsat enhanced thematic mapper. The SPOT VGT forest cover predicted forest area and location well, so we combined it with elevation data to refine coarse distribution maps for forest endemic birds. Stacking these species distribution maps enabled identification of the subregion richest in threatened birds—the lowland forests of Rio de Janeiro State. We highlighted eight priority fragments, focusing on one with finer resolved imagery for detailed study. This method allows prioritization of areas for conservation from a region >1 million km² to forest fragments of tens of square kilometers. To set priorities for biodiversity conservation, coarse biological information is sufficient. Hence, our method is attractive for tropical and biologically rich locations, where species location information is sparse.     

APPLICATION OF A MULTIPURPOSE UNEQUAL PROBABILITY STREAM SURVEY IN THE MID‐ATLANTIC COASTAL PLAIN1

ABSTRACT: A stratified, spatially balanced sample with unequal probability selection was used to design a multipurpose survey of headwater streams in the Mid‐Atlantic Coastal Plain. Objectives for the survey include unbiased estimates of regional stream conditions, and adequate coverage of unusual but significant environmental settings to support empirical modeling of the factors affecting those conditions. The design and field application of the survey are discussed in light of these multiple objectives. A probability (random) sample of 175 first‐order nontidal streams was selected for synoptic sampling of water chemistry and benthic and riparian ecology during late winter and spring 2000. Twenty‐five streams were selected within each of seven hydrogeologic subre‐gions (strata) that were delineated on the basis of physiography and surficial geology. In each subregion, unequal inclusion probabilities were used to provide an approximately even distribution of streams along a gradient of forested to developed (agricultural or urban) land in the contributing watershed. Alternate streams were also selected. Alternates were included in groups of five in each subregion when field reconnaissance demonstrated that primary streams were inaccessible or otherwise unusable. Despite the rejection and replacement of a considerable number of primary streams during reconnaissance (up to 40 percent in one subregion), the desired land use distribution was maintained within each hydrogeologic subregion without sacrificing the probabilistic design.     

Associations of Forest Cover,Fragment Area,and Connectivity with Neotropical Understory Bird Species Richness and Abundance

Theoretical and empirical studies demonstrate that the total amount of forest and the size and connectivity of fragments have nonlinear effects on species survival. We tested how habitat amount and configuration affect understory bird species richness and abundance. We used mist nets (almost 34,000 net hours) to sample birds in 53 Atlantic Forest fragments in southeastern Brazil. Fragments were distributed among 3 10,800‐ha landscapes. The remaining forest in these landscapes was below (10% forest cover), similar to (30%), and above (50%) the theoretical fragmentation threshold (approximately 30%) below which the effects of fragmentation should be intensified. Species‐richness estimates were significantly higher (F= 3715, p = 0.00) where 50% of the forest remained, which suggests a species occurrence threshold of 30–50% forest, which is higher than usually occurs (<30%). Relations between forest cover and species richness differed depending on species sensitivity to forest conversion and fragmentation. For less sensitive species, species richness decreased as forest cover increased, whereas for highly sensitive species the opposite occurred. For sensitive species, species richness and the amount of forest cover were positively related, particularly when forest cover was 30–50%. Fragment size and connectivity were related to species richness and abundance in all landscapes, not just below the 30% threshold. Where 10% of the forest remained, fragment size was more related to species richness and abundance than connectivity. However, the relation between connectivity and species richness and abundance was stronger where 30% of the landscape was forested. Where 50% of the landscape was forested, fragment size and connectivity were both related to species richness and abundance. Our results demonstrated a rapid loss of species at relatively high levels of forest cover (30–50%). Highly sensitive species were 3‐4 times more common above the 30–50% threshold than below it; however, our results do not support a unique fragmentation threshold. Asociaciones de la Cobertura Forestal, Superficie del Fragmento y Conectividad con la Riqueza y Abundancia de Aves Neotropicales de Sotobosque