20 resultados para After-images.

em Aquatic Commons


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One of the most important marine ecological phenomena is red tide which is created by increasing of phytoplankton population, influenced by different factors such as climate condition changes, utrification hydrological factors and can leave sever and undesired ecological and economical effects behind itself in the case of durability. Coast line of Hormozgan is about 900km from east to west, within the range of geographical coordinates of 56 16 23.8, 26 58 8.8 to 54 34 5.33 and 26 34 32 eastern longitude and northern latitude, seven sampling stations were considered and sampled for a period of one year from October 2008 to October 2009. after the analysis of Satellite images, monthly, during the best time. In several stages, samplings were performed. In each station, three samples were collected for identification and determination of Bloom- creating species abundance. Cochlodinium polykrikoides was the species responsible for the discoloration which occurred at October 2008 in Hormozgan marine water. Environmental parameters such as sea surface temperature, pH, salinity, Dissolved Oxygen concentration, Total Dissolved Solids (T.D.S.), conductivity, nitrate, nitrite and phosphate and also chlorophyll a were measured and calculated. Kruscal Wallis test was used to compare the densities between different months, seasons and the studied stations. Mann-whitney test from Nonparametric Tests was used for couple comparison. Pearson correlation coefficient was used to determine the relationship between physical and chemical data set and the abundance of Cochlodinium polykrikoides. Multivariate Regression and analysis of variance (ANOVA) also were used to obtain the models and equations of red tide occurrence relationship, environmental parameters and nutrient data. The highest density was 26 million cells per liter in Qeshm station. A meaningful difference was observed between sampling months and seasons but there was no between sampling stations which indicates that in favorable conditions, the occurrence of this phenomenon by the studied species is probable. Regarding to β coefficients of nitrate, temperature, phosphate, Total Dissolvable Solutions (T.D.S) and pH these parameters are effective on the abundance of this species and red tide occurrence. Increase in these factors can represent the effects and outcomes of human activities and increase in marine pollution.

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(Document pdf contains 193 pages) Executive Summary (pdf, < 0.1 Mb) 1. Introduction (pdf, 0.2 Mb) 1.1 Data sharing, international boundaries and large marine ecosystems 2. Objectives (pdf, 0.3 Mb) 3. Background (pdf, < 0.1 Mb) 3.1 North Pacific Ecosystem Metadatabase 3.2 First federation effort: NPEM and the Korea Oceanographic Data Center 3.2 Continuing effort: Adding Japan’s Marine Information Research Center 4. Metadata Standards (pdf, < 0.1 Mb) 4.1 Directory Interchange Format 4.2 Ecological Metadata Language 4.3 Dublin Core 4.3.1. Elements of DC 4.4 Federal Geographic Data Committee 4.5 The ISO 19115 Metadata Standard 4.6 Metadata stylesheets 4.7 Crosswalks 4.8 Tools for creating metadata 5. Communication Protocols (pdf, < 0.1 Mb) 5.1 Z39.50 5.1.1. What does Z39.50 do? 5.1.2. Isite 6. Clearinghouses (pdf, < 0.1 Mb) 7. Methodology (pdf, 0.2 Mb) 7.1 FGDC metadata 7.1.1. Main sections 7.1.2. Supporting sections 7.1.3. Metadata validation 7.2 Getting a copy of Isite 7.3 NSDI Clearinghouse 8. Server Configuration and Technical Issues (pdf, 0.4 Mb) 8.1 Hardware recommendations 8.2 Operating system – Red Hat Linux Fedora 8.3 Web services – Apache HTTP Server version 2.2.3 8.4 Create and validate FGDC-compliant Metadata in XML format 8.5 Obtaining, installing and configuring Isite for UNIX/Linux 8.5.1. Download the appropriate Isite software 8.5.2. Untar the file 8.5.3. Name your database 8.5.4. The zserver.ini file 8.5.5. The sapi.ini file 8.5.6. Indexing metadata 8.5.7. Start the Clearinghouse Server process 8.5.8. Testing the zserver installation 8.6 Registering with NSDI Clearinghouse 8.7 Security issues 9. Search Tutorial and Examples (pdf, 1 Mb) 9.1 Legacy NSDI Clearinghouse search interface 9.2 New GeoNetwork search interface 10. Challenges (pdf, < 0.1 Mb) 11. Emerging Standards (pdf, < 0.1 Mb) 12. Future Activity (pdf, < 0.1 Mb) 13. Acknowledgments (pdf, < 0.1 Mb) 14. References (pdf, < 0.1 Mb) 15. Acronyms (pdf, < 0.1 Mb) 16. Appendices 16.1. KODC-NPEM meeting agendas and minutes (pdf, < 0.1 Mb) 16.1.1. Seattle meeting agenda, August 22–23, 2005 16.1.2. Seattle meeting minutes, August 22–23, 2005 16.1.3. Busan meeting agenda, October 10–11, 2005 16.1.4. Busan meeting minutes, October 10–11, 2005 16.2. MIRC-NPEM meeting agendas and minutes (pdf, < 0.1 Mb) 16.2.1. Seattle Meeting agenda, August 14-15, 2006 16.2.2. Seattle meeting minutes, August 14–15, 2006 16.2.3. Tokyo meeting agenda, October 19–20, 2006 16.2.4. Tokyo, meeting minutes, October 19–20, 2006 16.3. XML stylesheet conversion crosswalks (pdf, < 0.1 Mb) 16.3.1. FGDCI to DIF stylesheet converter 16.3.2. DIF to FGDCI stylesheet converter 16.3.3. String-modified stylesheet 16.4. FGDC Metadata Standard (pdf, 0.1 Mb) 16.4.1. Overall structure 16.4.2. Section 1: Identification information 16.4.3. Section 2: Data quality information 16.4.4. Section 3: Spatial data organization information 16.4.5. Section 4: Spatial reference information 16.4.6. Section 5: Entity and attribute information 16.4.7. Section 6: Distribution information 16.4.8. Section 7: Metadata reference information 16.4.9. Sections 8, 9 and 10: Citation information, time period information, and contact information 16.5. Images of the Isite server directory structure and the files contained in each subdirectory after Isite installation (pdf, 0.2 Mb) 16.6 Listing of NPEM’s Isite configuration files (pdf, < 0.1 Mb) 16.6.1. zserver.ini 16.6.2. sapi.ini 16.7 Java program to extract records from the NPEM metadatabase and write one XML file for each record (pdf, < 0.1 Mb) 16.8 Java program to execute the metadata extraction program (pdf, < 0.1 Mb) A1 Addendum 1: Instructions for Isite for Windows (pdf, 0.6 Mb) A2 Addendum 2: Instructions for Isite for Windows ADHOST (pdf, 0.3 Mb)

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Executive Summary: Circulation and Exchange of Florida Bay and South Florida Coastal Waters The coastal ecosystem of South Florida is comprised of distinct marine environments. Circulation of surface waters and exchange processes, which respond to both local and regional forcings, interconnect different coastal environments. In addition, re-circulating current systems within the South Florida coastal ecosystem such as the Tortugas Gyre contribute to retention of locally spawned larvae. Variability in salinity, chlorophyll, and light transmittance occurs on a wide range of temporal and spatial scales, in response to both natural forcing, such as seasonal precipitation and evaporation and interannual “El Niño” climate signals, and anthropogenic forcing, such as water management practices in south Florida. The full time series of surface property maps are posted at www.aoml.noaa.gov/sfp. Regional surface circulation patterns, shown by satellite-tracked surface drifters, respond to large-scale forcing such as wind variability and sea level slopes. Recent patterns include slow flow from near the mouth of the Shark River to the Lower Keys, rapid flow from the Tortugas to the shelf of the Carolinas, and flow from the Tortugas around the Tortugas Gyre and out of the Florida Straits. The Southwest Florida Shelf and the Atlantic side of the Florida Keys coastal zone are directly connected by passages between the islands of the Middle and Lower Keys. Movement of water between these regions depends on a combination of local wind-forced currents and gravitydriven transports through the passages, produced by cross-Key sea level differences on time scales of several days to weeks, which arise because of differences in physical characteristics (shape, orientation, and depth) of the shelf on either side of the Keys. A southeastward mean flow transports water from western Florida Bay, which undergoes large variations in water quality, to the reef tract. Adequate sampling of oceanographic events requires both the capability of near real-time recognition of these events, and the flexibility to rapidly stage targeted field sampling. Capacity to respond to events is increasing, as demonstrated by investigations of the 2002 “blackwater” event and a 2003 entrainment of Mississippi River water to the Tortugas. (PDF contains 364 pages.)

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Oreochrimis niloticus (L.) was introduced to Lake victoria in the 1950s. It remained relatively uncommon in catches until 1965, when the numbers began to increase dramatically. It is now the third most important commercial fish species after the Nile perch, Lates niloticus (L.) and Rastrineobola argentea (Pellegrin). Oreochromis niloticus is considered a herbivore, feeding mostly on algae and plant material. The diet now appears to be more diversified , with insects, fish, algae and plant materials all being important food items. Fish smaller than 5 cm TL have a diverse diet but there is a decline in the importance of zooplankton, the preferred food item of small fish, as fish get larger. The shift in diet could be due to changes which have occurred in the lake. Water hyacinth, Eichhornia crassipes (Mart.) Solms, which harbours numerous insects in its root balls, now has extensively coverage over the lake. The native fish species which preyed on these insects (e.g. haplochromines) have largely been eliminated and O. niloticus could be filling niches previously occupied by these cichlids and non cichlid fishes. The change in diet could also be related to food availability and abundance where the fish is feeding on the most readily available food items.

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The report describes the results of preliminary analyses of data obtained from a series of water temperature loggers sited at various distances (0.8 to 21.8 km) downstream of Kielder dam on the River North Tyne and in two natural tributaries. The report deals with three aspects of the water temperature records: An analysis of an operational aspect of the data sets for selected stations, a simple examination of the effects of impoundment upon water temperature at or close to the point of release, relative to natural river temperatures, and an examination of rate of change of monthly means of daily mean, maximum, minimum and range (maximum - minimum) with distance downstream of the point of release during 1983.

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This report describes the general background to the project, defines the stations from which data sets have been obtained and lists the available data. The project had the following aims: To develop a more accurate and less labour-intensive system for the collection and processing of water temperature data from a number of stations within a stream/river system, and to use the River North Tyne downstream of the Kielder impoundment as a test bed for the system. This should yield useful information on the effects of impoundment upon downstream water temperatures.

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Hatchling American Alligators (Alligator mississippiensis) produced from artificially incubated wild eggs were returned to their natal areas (repatriated). We compared artificially incubated and repatriated hatchlings released within and outside the maternal alligator’s home range with naturally incubated hatchlings captured and released within the maternal alligator’s home range on Lake Apopka, Lake Griffin, and Orange Lake in Florida. We used probability of recapture and total length at approximately nine months after hatching as indices of survival and growth rates. Artificially incubated hatchlings released outside of the maternal alligator’s home range had lower recapture probabilities than either naturally incubated hatchlings or artificially incubated hatchlings released near the original nest site. Recapture probabilities of other treatments did not differ significantly. Artificially incubated hatchlings were approximately 6% shorter than naturally incubated hatchlings at approximately nine months after hatching. We concluded that repatriation of hatchlings probably would not have long-term effects on populations because of the resiliency of alligator populations to alterations of early age-class survival and growth rates of the magnitude that we observed. Repatriation of hatchlings may be an economical alternative to repatriation of older juveniles for population restoration. However, the location of release may affect subsequent survival and growth.

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The hypothesis that heavy fishing pressure has led to changes in the biological characteristics of the estuary cobbler (Cnidoglanis macrocephalus) was tested in a large seasonally open estuary in southwestern Australia, where this species completes its life cycle and is the most valuable commercial fish species. Comparisons were made between seasonal data collected for this plotosid (eeltail catfish) in Wilson Inlet during 2005–08 and those recorded with the same fishery-independent sampling regime during 1987–89. These comparisons show that the proportions of larger and older individuals and the catch rates in the more recent period were far lower, i.e., they constituted reductions of 40% for fish ≥430 mm total length, 62% for fish ≥4 years of age, and 80% for catch rate. In addition, total mortality and fishing-induced mortality estimates increased by factors of ~2 and 2.5, respectively. The indications that the abundance and proportion of older C. macrocephalus declined between the two periods are consistent with the perception of long-term commercial fishermen and their shift toward using a smaller maximum gill net mesh to target this species. The sustained heavy fishing pressure on C. macrocephalus between 1987–89 and 2005–08 was accompanied by a marked reduction in length and age at maturity of this species. The shift in probabilistic maturation reaction norms toward smaller fish in 2005–08 and the lack of a conspicuous change in growth between the two periods indicate that the maturity changes were related to fishery-induced evolution rather than to compensatory responses to reduced fish densities.

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Millions of crabs are sorted and discarded in freezing conditions each year in Alaskan fisheries for Tanner crab (Chionoecetes bairdi) and snow crab (C. opilio). However, cold exposures vary widely over the fishing season and among different vessels, and mortalities are difficult to estimate. A shipboard experiment was conducted to determine whether simple behavioral observations can be used to evaluate crab condition after low-temperature exposures. Crabs were systematically subjected to cold in seven different exposure treatments. They were then tested for righting behavior and six different ref lex actions and held to monitor mortality. Crabs lost limbs, showed ref lex impairment, and died in direct proportion to increases in cold exposure. Righting behavior was a poor predictor of mortality, whereas reflex impairment (scored as the sum of reflex actions that were lost) was an excellent predictor. This composite index could be measured quickly and easily in hand, and logistic regression revealed that the relationship between reflex impairment and mortality correctly predicted 80.0% of the mortality and survival for C. bairdi, and 79.4% for C. opilio. These relationships provide substantial improvements over earlier approaches to mortality estimation and were independent of crab size and exposure temperature.

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Fishing communities around the Indian Ocean were severely affected by the December 2004 tsunamis. Programs for rebuilding coastal fisheries livelihoods need to address the pre-tsunami situation that was characterized by overfishing and degraded natural resources. Adopting appropriate strategies to ensure sustainable livelihoods will require community involvement, as well as cross-sectoral, integrated planning and management at ascending government levels. Key recommendations from the WorldFish Center study Sustainable Management of Coastal Fish Stocks in Asia are presented to encourage discussion and debate.

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Body length measurement is an important part of growth, condition, and mortality analyses of larval and juvenile fish. If the measurements are not accurate (i.e., do not reflect real fish length), results of subsequent analyses may be affected considerably (McGurk, 1985; Fey, 1999; Porter et al., 2001). The primary cause of error in fish length measurement is shrinkage related to collection and preservation (Theilacker, 1980; Hay, 1981; Butler, 1992; Fey, 1999). The magnitude of shrinkage depends on many factors, namely the duration and speed of the collection tow, abundance of other planktonic organisms in the sample (Theilacker, 1980; Hay, 1981; Jennings, 1991), the type and strength of the preservative (Hay, 1982), and the species of fish (Jennings, 1991; Fey, 1999). Further, fish size affects shrinkage (Fowler and Smith, 1983; Fey, 1999, 2001), indicating that live length should be modeled as a function of preserved length (Pepin et al., 1998; Fey, 1999).

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In this note we describe the re-formation of a spawning aggregation of mutton snapper (Lutjanus analis). A review of four consecutive years of survey data indicates that the aggregation may be increasing in size. Mutton snapper are distributed in the temperate and tropical waters of the western Atlantic Ocean from Florida to southeastern Brazil (Burton, 2002). Juveniles and subadults are found in a variety of habitats such as vegetated sand bottoms, bays, and mangrove estuaries (Allen, 1985). Adults are found offshore on coral reefs and other complex hardbottom habitat. They are solitary and wary fish, rarely found in groups or schools except during spawning aggregations (Domeier et al., 1996). Spawning occurs from May through July at Riley’s Hump (Domeier et al., 1996) and peaks in June, as indicated by gonadosomatic indices (M. Burton, unpubl. data). Mutton snapper are highly prized by Florida fishermen for their size and fighting ability, and the majority of landings occur from Cape Canaveral, through the Florida Keys, including the Dry Tortugas (Burton, 2002).

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Since 1988 regulations have required U.S. longline fishermen to release all Atlantic white marlin, Tetrapturus albidus. By the late 1990’s, approximately 99% of Atlantic white marlin caught by U.S. recreational fishermen were released. Recent studies using PSAT technology indicate that not all released fish survive and that a minor change in hook type, 0–5° offset circle hooks rather than straight-shank “J” hooks, may have a profound effect on post release mortality. Beginning in 2004, sea turtle mitigation measures have required U.S. longline fishermen to use circle hooks. Estimates of total catch, releases, and post release mortality of Atlantic white marlin caught by U.S. recreational fishermen were made in order to evaluate the potential reduction in mortality that may be realized by requiring the use of circle hooks rather than straight-shank “J” hooks by U.S. recreational fishermen. These estimates were compared to estimates of Atlantic white marlin caught by the U.S. longline fishery