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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Towards an Ecosystem Approach for Non-Target Reef Fishes: Habitat Uses and Population Dynamics of South Florida Parrotfishes (Perciformes: Scaridae)

Molina-Ureña, Helena 14 May 2009 (has links)
The goal of this research was to develop statistically robust ecosystem-based approaches, while optimizing data acquisition on relatively unexploited fish species in South Florida reefs, i.e., parrotfishes, Family Scaridae, in Biscayne Bay (with seasonal roller frame beam trawl surveys, 1996-2000) and Florida Keys (with annual Reef Fish Visual Censuses, 1997-2001), by following these steps: (I) analysis of information gaps for the stocks, including systematics, biogeography, population dynamics, reproductive ecology, trophodynamics, habitat use, and fisheries dynamics of Western Atlantic parrotfishes; (II) determination of primary research objectives from prioritization in Step I; (III) determination of essential fish habitats, ontogenetic shifts, migrations, and reef-seagrass habitat, from integration of stratified sampling design for fisheries-independent surveys, habitat selection theory-based analyses, and length-based analyses; (IV) estimation of population dynamics and fisheries-specific parameters encompassing life history demographics from empirical data or comparisons to theoretical expectations adapted to local conditions; (V) simulation modeling of a realistic range of fishing scenarios and demographic characteristics to evaluate the efficacy of potential traditional fisheries and spatial management strategies; and (VI) application of sampling optimization procedures and fisheries ecology approaches. Four scarid species had an estimated combined abundance of ca. 36.8 x 106 individuals in the Florida Keys. Connectivity among seagrass beds, coral reefs and deep waters had three major patterns: seagrass dwellers, reef dwellers, with inshore-to-offshore ontogenetic , and a seagrass-reef connection, using Biscayne Bay as an important recruitment ground. Marine protected areas of the Florida Keys National Marine Sanctuary did not show effects on abundance, size composition or spatial distribution of any parrotfish studied. Simulations suggested relatively short longevities (5-10 years), moderate body growth curvature, high instantaneous natural mortality rates (0.3-0.6 y super minus one), and low annual survival rates (27-54%). Simulated estimates of fishing mortalities ranged from 0.3 to 0.6 y super minus one, indicating low levels of exploitation, but low Spawning Potential Ratios (SPR = 23.5-26%). Proposed potential exploitation based on a legal minimum size equal to their size at first maturity and fishing rates equal or below to their natural mortality should secure SPR values at 45-48%.
32

Conserving Fish and Forests: Community Involvement and Its Limits in Resource Management On the Island of Hawai'i

Datta, Amber W 01 May 2013 (has links)
In this thesis I examine the limits of community involvement in accomplishing the conservation goals of biodiversity and ecosystem function in resource management by analyzing the multiple interest groups that compose community. Two case studies are presented to accomplish this goal. The first case study is the West Hawaii Fisheries Management Area, where a group of community stakeholders provide management recommendations that are then implemented by the state. The second case study is the Ka’u forest reserve, where community involvement is invited into the management decision-making process but is also limited in its ultimate political power by the state. Through an examination of these cases I find that the ability of community involvement to accomplish conservation goals is limited when powerful interest groups within the community oppose these goals.
33

Good Governance of A Marine Nation: Establishing Institutions on Marine Protected Areas for Taiwan

Chen, Tai-An 08 September 2012 (has links)
This dissertation uses ¡§marine good governance¡¨ as the core to discuss the establishment of marine protected areas institutions in Taiwan. As a marine nation, it is a fatal key whether Taiwan can properly manage marine resources or not. Appropriately dealing with marine-related affairs can bring success to overall national development. The marine environmental diversity makes its affairs much more complicated than the land area. The global cognition of marine management has greatly changed. ¡§The concept of public management¡¨ has shifted from ¡§government¡¨ to ¡§governance¡¨. Good governance is the aim of public management nowadays. A marine nation should aim to have good marine governance. Establishing integrated marine institutions would be the key point. Although the quantity of Taiwan¡¦s marine protected areas has greatly increased, the effectiveness of management on marine protected areas is still called into question. This dissertation recommends that Taiwan should focus on integrating the institutions on marine protected areas. The future Marine Affair Organization and the corresponding marine governance legal structure would result in a ¡§Good Governance of a Marine Nation¡¨.
34

Implications of complex connectivity patterns, disturbance, Allee effects, and fisheries in the dynamics of marine metapopulations

Peña-Baca, Tania Sarith 09 July 2014 (has links)
Nearshore populations have been depleted and some have not yet recovered. Therefore, theoretical studies focus on improving fisheries management and designing marine protected areas (MPAs). Depleted populations may be undergoing an Allee effect, i.e. a decrease in fitness at low densities. Here, I constructed a marine metapopulation model that included pre- and post-dispersal Allee effects using a network theory approach. Networks represent metapopulations as groups of nodes connected by dispersal paths. With this model I answered four questions: What is the role of Allee effects on habitat occupancy? Are MPAs effective in recovering exploited populations? What is the importance of larval dispersal patterns in preventing local extinctions due to exploitation and Allee effects? Can exploitation fragment nearshore metapopulations? When weak Allee effects are included, habitat occupancy drops as larval retention decreases because more larvae are lost to unsuitable habitat. With strong Allee effects habitat occupancy also drops at high larval retention because more larvae are needed to overcome the Allee effect. Post-dispersal Allee effects seem more detrimental for nearshore metapopulations. MPA effectiveness seems also lower in a post-dispersal Allee effect scenario. In overexploited systems, local populations that go extinct are also less likely to recover even after protecting the whole coastline. In exploited nearshore metapopulations with Allee effects, local occupancy or the recovery of local populations depends not only on larval inflow from neighbor populations, but also on larval inflow for these neighbors. Nearshore metapopulations with intense fishing mortality and Allee effects may also suffer a decrease in dispersal strength and fragmentation. Population fragmentation occurs when large populations are split into smaller groups. A tool for detecting partitioning in a network is modularity. The modularity analysis performed for red abalone in the Southern California Bight showed that exploitation increases partitioning through time before the entire metapopulation collapses. These findings call for research effort in estimating the strength of potential Allee effects to prevent stock collapse and assess MPA effectiveness, evaluating the predictability of local occupancy by centrality metrics to help identify important sites for conservation, and using modularity analysis to quantify the health of exploited metapopulations to prevent their collapse. / text
35

Conservation and compliance: a quantitative assessment of recreational fisher compliance in Rockfish Conservation Areas

Lancaster, Darienne 13 August 2015 (has links)
Concerns about declines in marine biodiversity led to the creation of marine protected areas and spatial fishery closures as tools for recovery. Yet many marine conservation areas suffer low levels of compliance from diverse fishing populations, including recreational fishers. Little research quantifies levels of recreational fisher compliance and its drivers, especially in temperate marine environments, despite the prevalence of this kind of fishing in some regions. This thesis addresses this knowledge gap through a study of recreational fisher compliance in Rockfish Conservation Areas (RCAs) in British Columbia, Canada. One hundred and sixty four RCAs were implemented between 2003 and 2007 and now cover 4847.2 km2. These conservation areas were created in response to widespread concern from fishers and non-governmental organizations about inshore rockfish population declines. However, recent research suggested that recreational fisher compliance might be low. This thesis had two goals: 1) contribute to knowledge about, and develop methods of assessing, non-compliance within marine conservation areas, and 2) address the immediate problem of suspected recreational non-compliance in RCAs. I had the following objectives: 1) Assess ecological and social RCA effectiveness to date, using a framework for improving governance from the literature on common pool resources; 2) Assess recreational fisher knowledge and perceptions of RCAs, and 3) Quantify non-compliance and social and ecological compliance drivers in RCAs. Methods included a literature review, structured surveys with 325 recreational fishers at 16 locations in the Salish Sea (Southern Gulf Islands and Victoria area), and trail camera monitoring in 42 coastal locations (both RCAs and unprotected sites). Results show that recreational fisher knowledge and compliance to RCA regulations is low. The assessment of social and ecological effectiveness shows much room for management improvement for recreational fisheries. This finding is supported by my survey and trail camera data. I found that 25.5% of recreational fishers had never heard of RCAs and ~60% were unsure of RCA locations. The total non-compliance rate was 23% in RCAs. Seventy nine percent of trail camera monitored RCA sites showed confirmed or probable fishing activity, with no significant difference between fishing effort inside and outside RCAs. However, 77% of fishers surveyed believed that rockfish conservation is necessary with advertising, fisher education, and increased monitoring offered as solutions to non-compliance. I recommend managers implement a public outreach and education campaign to address low levels of compliance. This study suggests that positive perceptions of marine conservation areas and conservation initiatives are not enough to create high compliance. Educating stakeholders and creating high levels of awareness should be an essential first step when creating marine conservation areas. My research offers important insights into the study of non-compliance, and the immediate problem of recreational non-compliance in BC’s RCAs. My successful use of a simple and cost/time efficient multiple methods approach to assessing compliance provides robust tools for future compliance analyses, and hence provides a valuable contribution to the compliance literature. The study also suggests that trail camera monitoring could be a promising new method for monitoring coastal conservation areas. / Graduate / 0768 / 0792 / 0306
36

Resilience at Risk: Epistemological and Social Construction Barriers to Risk Communication

Stoffle, Richard W., Minnis, Jessica 01 January 2008 (has links)
This paper is about the persistent failure of social scientists to bring into the Environmental Impact Assessment (EIA) process socially constructed environmental concerns held by potentially impacted communities. The failure to communicate perceived risks results from a two-communities divide based on both epistemological differences and obfuscation due to vernacular communication. The analysis provides robust modeling variables that can bridge this social-environmental divide. The case involves data collected from members of traditional communities regarding their perceptions of the potential impacts of proposed Marine Protected Areas (MPAs). The study is situated in the Bahamas where the government has approved setting aside 30 No-take MPAs to protect their sea. This analysis is based on 572 interviews conducted during eight field trips with members of six traditional settlements in the Exuma Islands and Cays in the central Bahamas. Confidence in the findings is high because the sample involves 34% of the census population of these settlements and the findings have repeatedly been returned for review and approval by the members of these settlements.
37

At the Sea’s Edge: Elders and Children in the Littorals of Barbados and the Bahamas

Stoffle, Brent W., Stoffle, Richard W. 27 January 2007 (has links)
Littorals in the in the Exuma Cays, Bahamas and the Bath Plantation, Barbados are comparative in many ways. These edges of the sea have provided critical services to local people during the time of slavery and since. More than food and medicine, the littoral is the nightly sea bath, where children are instructed, and the last ecosystem effectively used by the elderly. Independence and self- respect derive from use and protection of these littoral by individuals and communities. Local patterns of conservation and use are argued to be essential in the ecological structure and functions of the littoral. Development projects and marine protected areas alike are seen as potentially breaking local ties with the littoral causing trophic skew and damaging local society. If development occurs, mitigation solutions potentially derive from legally recognizing local people as partners in the co-management of their traditional littoral. Included with this article is a presentation prepared by Drs. Brent and Richard Stoffle.
38

Αλιευτική δραστηριότητα και διαχείριση στον Κορινθιακό και Πατραϊκό κόλπο

Χριστοδούλου, Βασίλης 26 October 2009 (has links)
Η αλιεία σε παγκόσμιο επίπεδο παίζει σημαντικό ρόλο στην εξασφάλιση τροφής και κυρίως στην τροφοδότηση του ανθρώπινου πληθυσμού με χαμηλής εμπορικής αξίας πρωτεΐνη. Αρκετά κράτη με αναπτυσσόμενες οικονομίες στηρίζονται στην αλιεία, αλλά και πολλές τοπικές κοινωνίες έχουν υψηλή οικονομική εξάρτηση από αυτήν. Οι λανθασμένες εκτιμήσεις των αποθεμάτων και η ποιότητα των δεδομένων έχει προκαλέσει σε πολλές περιοχές του κόσμου μείωση των αποθεμάτων και/ή την κατάρρευση τους. Ο Κορινθιακός και ο Πατραϊκός κόλπος είναι ιδιαιτέρα οικοσυστήματα με μεγάλη ανθρωπογενή δραστηριότητα, η ανάπτυξη της παραλιακής ζώνης, η βιομηχανική ανάπτυξη, τα μεγάλα έργα υποδομής και η αλιεία επιδρούν στο οικοσύστημα και στους θαλάσσιους οργανισμούς. Όσον αφορά την αλιεία, ο αλιευτικός στόλος της περιοχής βάση του ΚΑΜ (2007) παρουσιάζει μια τάση μείωσης τόσο σε αριθμό όσο και σε τεχνικά χαρακτηριστικά. Η αλιευτική παραγωγή φαίνεται τα τελευταία χρόνια να ακολουθεί μία σταθεροποιητική τάση τόσο για τον Κορινθιακό όσο και για τον Πατραϊκό κόλπο πού υποδεικνύει σταθεροποίηση της αλιευτικής εκμετάλλευσης. Όμως τα δεδομένα που χρησιμοποιήθηκαν για την εκτίμηση της αλιευτικής παραγωγής παρουσιάζουν έλλειμμα ποιότητας αφού η παραγωγή του Πατραϊκού κόλπου από το 1994 και μετά αυξάνει απότομα και παραμένει σε πολύ υψηλά επίπεδα. Άρα οποιαδήποτε εκτίμηση για υπεραλίευση ή μη των αποθεμάτων των δύο κόλπων δεν μπορεί να γίνει. Για να μπορέσει να γίνει εκτίμηση των πιέσεων που δέχονται οι δύο κόλποι πρέπει να υπάρχουν ακριβή και αξιόπιστα δεδομένα ώστε κάθε διαχειριστικό μέτρο που θα αποφασιστεί, να λειτουργήσει θετικά και να μην μεταθέσει ή οξύνει το πρόβλημα. Ο αλιευτικός στόλος της παράκτιας αλιείας παρουσιάζει ρυθμό μείωσης (25%) μεγαλύτερο από αυτόν του Ελληνικού μέσου όρου (22%), επιπροσθέτως ο μεγάλος μέσος όρος ηλικίας των αλιέων και η μικρή ή ανύπαρκτη είσοδος των παιδίων τους στο επάγγελμα μας οδηγεί στο συμπέρασμα ότι η παράκτια αλιεία συρρικνώνεται στην περιοχή μελέτης. Η δραστηριοποίηση των παρακτίων αλιέων γίνεται σχεδόν κατά μήκος όλης της ακτογραμμής και χρησιμοποιούν δίχτυα (απλάδια και μανωμένα) καθώς και παραγάδια βυθού. Το κύριο είδος στόχος είναι ο μπακαλιάρος που συλλαμβάνεται από όλα τα εργαλεία, ενώ δευτερεύοντα είναι ένας μεγάλος αριθμός ειδών που αλλάζουν από περιοχή σε περιοχή δείχνοντας μεγάλη ετερογένεια βιοτόπων. Τους θερινούς μήνες παρατηρείται αύξηση της αλιευτικής προσπάθειας τόσο της παράκτιας όσο και της ερασιτεχνικής αλιείας, δημιουργώντας ανταγωνισμό μεταξύ των δύο κλάδων τόσο για το απόθεμα όσο και για τον χώρο και την αγορά. Η ερασιτεχνική αλιεία αναδεικνύεται 4 τρίτο σημαντικότερο πρόβλημα στην περιοχή, γεγονός που φαίνεται και από την ραγδαία αύξηση των σκαφών της μέσα σε μικρό χρονικό διάστημα. Το 1996 η αναλογία ερασιτεχνικών προς επαγγελματικών σκαφών για την περιοχή του Κορινθιακού και του Πατραϊκού κόλπου ήταν 4:1 ενώ το 2007 για τον Ν. Αχαΐας η αναλογία ήταν 5:1 και για τον Ν. Κορινθίας 10:1. Τα διαχειριστικά μέτρα που έχουν ληφθεί στην περιοχή φαίνεται να αποδίδουν αφού είδη που θεωρούνταν υπερεκμεταλλευμένα φαίνεται να έχουν επανακάμψει, όμως η σύγχρονη τάση είναι η ολιστική αντιμετώπιση των οικοσυστημάτων μέσω των Θαλάσσιων Προστατευόμενων Περιοχών (ΘΠΠ). Έτσι προτείνονται τεχνικού τύπου μέτρα, βάση των διεθνών πρακτικών, ώστε η διαχείριση και η προστασία των δύο κόλπων να τεθεί σε ένα πλαίσιο τόσο οικολογικό όσο και κοινωνικο-οικονομικό. / In a world wide level, fishery plays important role in human nutrition. Fishery supplies human populations with low commercial value protein. Many countries with developing economies depend on fishery, so as local communities are highly depended on this sector. Erroneous estimations about fish stocks and low quality data have caused, in many areas of the world, reduction of fish stocks and in many cases, their collapse. Corinthian and Patraikos gulfs are ecosystems which suffer from intense human activity, reflected in domestic and tourist industry growth in coastal area, industrial growth, big constructions such as the Rio- Antirrio Bridge, the new Patras harbor and fishery. All these factors have a major impact on marine ecosystems and organisms. Concerning fishery, reduction is observed in number and in technical characteristics of the fishery fleet for Corinthiacos and Patraikos gulf. Fishery production seems to be stabilized during the last years for the two areas, a fact that suggests stabilization of the fishing effort. However, we can’t make estimations about overexploitation of the stocks in the study area because the quality of the data seems to be low. We came to this conclusion after analyzing the fishing production of Patraikos gulf. In order to evaluate the impacts of the fishery sector, precise and reliable data are needed. Those help us to adopt measures that actually work and don’t transpose and accentuate problems. Coastal fishery shrinks during last years because of the fact that the age average is high for fishermen and their children do not intend to work to this sector. Coastal fishermen are active almost around the coastline, while the gears used are gill nets, trammel nets and long lines. The target species is Merluccius merluccius for almost all gears. The great number and variety of non target species caught with the same gears in different areas, suggests great heterogeneity of biotopes. Increased fishing effort observed in summer months for the coastal fishery as well as for the recreational fishery, promotes competition between the two sectors. The factors to compete for are the stock, the space and the market. This study shows that recreational fishery becomes third in the list of the problems that the professional fishery has to cope with; a fact confirmed by the great increase of the recreational boats in a very short term. These restrictions that go for the study area, appear to be effective, since stocks that are considered overexploited seem to recover. However, the modern tendency is being reflected in the holistic approach of the ecosystems through Marine Protected Areas (MPA). Thus, technical measures are proposed according to international practices, orientated to an ecological and socioeconomic aspect.
39

Multiple perspectives for envisioning marine protected areas

Ban, Natalie Corinna 11 1900 (has links)
This thesis provides the first direct comparison between – and integration of – community-based and science-based approaches to the establishment of marine protected areas (MPAs). MPAs are one potentially effective conservation tool, but are being established very slowly. My research shows that community involvement in placing MPAs can help meet many ecological goals, although biophysical data improve the conservation value of sitings. To assess the need for MPAs in British Columbia (BC), Canada, I mapped stressors resulting from human activities. This produced a powerful rationale for MPAs: very little of the ocean, and almost none of the continental shelf of BC, lies beyond the reach of human stressors. My work helps reconcile differing perspectives about the efficacy of community-based vs. science-based MPA selection. I explored and analyzed these approaches, separately and together, in two areas in BC. First, I generated a community-based plan for MPA placement through partnerships with two First Nations (indigenous peoples) in BC. They offered strong support for spatial protection measures, and individuals nominated overlapping areas. Second, I applied a decision support tool (Marxan) to determine MPA placement under scientific precepts. Conservation planning usually lacks detailed ecological information but the Marxan approach was robust to some missing data; in such cases, it was best to use available abiotic and biotic data to ensure that both habitats and species were represented. Third, I integrated community-based and science-based approaches, to find that they verified and complemented each other. Indeed, an integration of the two was preferred by participants and also achieved all conservation objectives. Finally, I took a novel and pragmatic approach to ocean zoning. I used spatial data for thirteen commercial fisheries on Canada’s west coast to select areas where fishing should be permitted, rather than prohibiting fishing under a MPA paradigm. The results revealed that small reductions in fisheries yields, if judiciously selected, could allow creation of large unfished areas that embraced diverse biophysical regions and habitat types. Such a pragmatic approach could achieve remarkable conservation gains.
40

Multiple perspectives for envisioning marine protected areas

Ban, Natalie Corinna 11 1900 (has links)
This thesis provides the first direct comparison between – and integration of – community-based and science-based approaches to the establishment of marine protected areas (MPAs). MPAs are one potentially effective conservation tool, but are being established very slowly. My research shows that community involvement in placing MPAs can help meet many ecological goals, although biophysical data improve the conservation value of sitings. To assess the need for MPAs in British Columbia (BC), Canada, I mapped stressors resulting from human activities. This produced a powerful rationale for MPAs: very little of the ocean, and almost none of the continental shelf of BC, lies beyond the reach of human stressors. My work helps reconcile differing perspectives about the efficacy of community-based vs. science-based MPA selection. I explored and analyzed these approaches, separately and together, in two areas in BC. First, I generated a community-based plan for MPA placement through partnerships with two First Nations (indigenous peoples) in BC. They offered strong support for spatial protection measures, and individuals nominated overlapping areas. Second, I applied a decision support tool (Marxan) to determine MPA placement under scientific precepts. Conservation planning usually lacks detailed ecological information but the Marxan approach was robust to some missing data; in such cases, it was best to use available abiotic and biotic data to ensure that both habitats and species were represented. Third, I integrated community-based and science-based approaches, to find that they verified and complemented each other. Indeed, an integration of the two was preferred by participants and also achieved all conservation objectives. Finally, I took a novel and pragmatic approach to ocean zoning. I used spatial data for thirteen commercial fisheries on Canada’s west coast to select areas where fishing should be permitted, rather than prohibiting fishing under a MPA paradigm. The results revealed that small reductions in fisheries yields, if judiciously selected, could allow creation of large unfished areas that embraced diverse biophysical regions and habitat types. Such a pragmatic approach could achieve remarkable conservation gains.

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