• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 9
  • 4
  • 1
  • 1
  • Tagged with
  • 17
  • 17
  • 9
  • 5
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 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.
1

The study of the Bioeconomics analysis Of Grey mullet in Taiwan

Cheng, Man-chun 29 January 2007 (has links)
Abstract This study is based on the theory of biology and economy to establish the open access model, dynamic optimization model and static optimization of fishery mathematical models, to discuss the problem of fishery management. To be aimed at getting the equilibrium of resource stock and effort, research data are mainly analyzed by comparative statues. In so doing, the amount of grey mullet, collect and analyze the estimation of exogenous variable. Then, we can use Mathematica program to calculate the equilibrium value resource stock and the effort, and do the sensitivity analysis by standing on the change of estimation of exogenous variable. The result of analysis is as follow: These three fishery mathematical models¡¦ resource stock and effort are consistency. In another view of CPUE, it is not obvious of the economic effect of open access model. We must strengthen the management in policy of fishing for grey mullet, to let the fisherman earn the highest economic benefits. Keyword: open access model static optimization model. dynamic optimization model.
2

The biological and economical analysis of the resource of the shrimp Acetes intrmedius in TungKang,PingTung.

Yang, Chung-hao 27 June 2008 (has links)
The fishery of the shrimp Acetes intermedius in the southwestern coast of Taiwan has long history , and it is the food of many species of fishes and large-scale shrimps . Shrimp Acetes has not only fallen on dead ears , but also been ignored its importantce of ecologyical status in the southwestern coast by the academia because of less harvest and output value in the past . It then comes into operation the management of catch , leading the price going up and output value increasing rapidly when the establishment of TungKang producer organization of the shrimp Acetes intrmedius in 1994 , and it also becomes the important seasonal fishery . According to as was mentioned above , the study is based on the theory of biology and economy to put out the open access model , static optimization model and dynamic optimization of fishery mathematical models , and further discuss the problem of fishery management. In connection with getting the equilibrium of resource stock and effort , research data from the substitution of real data are mainly analyzed by compareative statues on exogenous variable .By means of understanding the sensitivity of variation on endogenous variable depending on exogenous variable , we can provide the member of TungKang producer organization of the shrimp Acetes intrmedius with the control on harvest and preservation of stock . The study can get the fact that the management of TungKang producer organization of the shrimp Acetes intrmedius has the notion of sustainable administration by the deriveation of theoretical model and the simulate analysis of historyical data. I hope the management of TungKang producer organization of the shrimp Acetes intrmedius can be popularized.
3

none

Wu, Hsiao-wen 27 July 2009 (has links)
In this study, the fundamental model of fish dynamic model- Gordon Schaefer Model is used to discuss the equilibrium levels for the Pacific Bluefin Tuna fishery of open access and dynamic optimization, and then to do the sensitivity analysis. By comparing the historical record of catch data with the equilibrium values of open access and dynamic optimization, we could know that the fish stocks and harvests of Pacific Bluefin Tuna are not in the condition of dynamic optimization. In order to ensure the sustainable development of Pacific Bluefin Tuna fishery, we have to take effective measures to preserve and manage the Pacific Bluefin Tuna resources. Finally, this study simulates and analyses the various management scenarios of the Pacific Bluefin Tuna fishery. The results of simulative analysis reveal that the optimal management of the Pacific Bluefin Tuna fishery would imply significant reallocation of the fishing gear shares. Furthermore, the net present value could increase substantially by reallocating the fishing gear shares.
4

Positive Analysis on the Stock Size of Argentine Shortfin Squid, Illex Argentinus in Southwest Atlantic

Wu, Pei-jung 08 July 2011 (has links)
This thesis is based on Gordon-Schaefer model, and assesses Argentine shortfin squid¡¦s stock by using the data of Southwest Atlantic from FAO between 1983 and 2009. First, estimate the equilibrium level of the open-access fishery and dynamic optimization fishery and compare to each other. Then estimate annual Argentine shortfin squid¡¦s stock size, comparing the stock size with the equilibrium level of the two fishery models. The result is that Argentine shortfin squid¡¦s stock size has no crisis of extinction now in Southwest Atlantic. In addition, simulate Argentine shortfin squid¡¦s stock size under management and no management status in the future. The result is that it will make the Argentine shortfin squid sustainable development under dynamic optimization fishery, and this fishery model will be a good management. Finally, this thesis based on the catch of Southwest Atlantic Argentine shortfin squid, which we figure out the fluctuation of catch by literatures, and do the sensitivity analysis.
5

Empirical analysis of Tong-Kong sakura shrimp fishery resources

Hsu, Chia-fen 08 July 2011 (has links)
Tong-Kong sakura shrimp is one of important fisheries in southwest coast. Tong-Kong sakura shrimp, blue fin tuna and mullet roe are called Three Treasures of Tong-Kong . It brings significant economic benefits for local residents. This research is based on Gordon-Schaefer Model theory that combines with fishery catch statistics and operational cost data. Also, we use these data to discuss open-access fishing ground and dynamically optimal fishing ground of balance status under equilibrium level. Next step is to do stimulation analysis that based on annual fishery catch statistics of sakura shrimp. After stimulation, we can make comparisons of equilibrium values of these two fishing grounds. From analysing fishery catch statistics and fishing resource we may know that it can shows that the management of sakura shrimp tends to dynamically optimal fishing ground, and also can state that the management mechanism of sakura shrimp is an ideal of sustainable management. Then, through the example, we can understand how each variation influences fishing resources and fishing effort of these two fishing grounds. Finally, we simulate fishing resources model of two fishing grounds to show the result. If we don¡¦t manage fishery of sakura shrimp well and keep uncontrolled fishing, not only the fishing ground will become an open-access fishery, but also fishing resources will become extinct. However, once we can manage fishing ground efficiently, it will become a dynamically optimal fishing ground and the fishery of sakura shrimp will develop sustainably.
6

Estimation of Thunnus alalunga stock and economic analysis in the Western and Central Pacific Fishery

Luo, Lan-shin 11 July 2011 (has links)
The study is based on Gordon-Schaefer model, using statistic data from Western and Central Pacific Fishery Commission to estimate the resource stock of Albacore between 1960 and 2009. Compare the equilibrium levels of open access model and present value maximization model with the real data, and the result shows that the real stock is close to the equilibrium of present value maximization model. The thesis uses sensitivity analysis to understand the impact of the changed parameters on stock and effort, and by using real examples to understand the impact of the changed situation on stock and effort. Finally, by simulating the stock of open access fishery and present value maximization fishery and government management nowadays fishery. The result shows the stock of government management fishery is higher than the stock of the present value maximization fishery, and the stock both are closed. The management is conservative and effective, hence the management will make the profit maximize and the resource continue forever to develop.
7

The stock assessment Analysis of the Thunnus obesus in the Western and Central Pacific Ocean

Liu, Yu-li 16 February 2012 (has links)
This study used the Gordon-Schaefer model to discuss the equilibrium levels for bigeye tuna in the Western and Central Pacific of open access and present value maximization. And then to compare the catches and the stocks on the two model¡¦s equilibrium value, the result shows the management of bigeye tuna in the Western and Central Pacific tend to present value maximization model. Following that, this paper did sensitivity analysis to understand the impact of the changed parameters on stock size and effort. Finally, using simulation analysis on open access model and present value maximization model. In open access model, the result shows that resources will face extinction crisis if the fishery is not controlled well. In the present value maximization model, the bigeye tuna would be sustainable management. This result is valuable for the fishery management authorities to maintain the development of fishery and cherishing ocean resources at the same time.
8

The biological and economical analysis of the resource of South Pacific albacore

Chiu, szu-wei 14 June 2009 (has links)
Abstract This study used the Gordon-Schaefer model to do resource economic analysis on the South Pacific albacore fishery in 1967-2007 . Evaluated the equilibrium standard of open access model and present value maximization model, and then compared them with the real data. The results indicates that the fishing yield, resource stock, effort and catch-per-unit-effort of south Pacific albacore is close to the equilibrium level of present value maximization model after year 2002, which means the South Pacific albacore fishing is under appropriate development. Following that, this paper did sensitivity analysis to understand the impact of the changed parameters on stock size and effort. Finally, using the simulation analysis on open access model and present value maximization model. In open access model, the result shows that resources will face extinction crisis if the fishery is not controlled well. In present value maximization model, the albacore fishery would sustainable management. This result is valuable for the fishery management authorities to maintain the development of fishery and cherishing ocean resources at the same time.
9

The bio-economic analysis of the Sergestid Shrimp in TungKung, PingTung.

Tang, Yu-min 15 June 2009 (has links)
Sergestid Shrimp contains rich nutrition, regards as a high-class aquatic product in Japan. The management of the catch has come into operation, and it¡¦s led the price raising and the output value increasing rapidly when the establishment of TungKung producer organization of the Sergestid Shrimp in 1993 and it also has become the important seasonal fishery in the southwestern coast of Taiwan. This study is based on the fundamental model of fish dynamic- Gordon Schaefer Model, to discuss the equilibrium values for the optimal conduction of open access and dynamic optimization, and to do the comparative statics analysis. By applying the data provided by Fisheries Research Institute, the evaluation of the variation are under both conductions were available, and in additions, the sensitivity analysis had been done by assuming all bio-economics parameters varied within a reasonable range. The study can figure out the fact that the management of TungKang producer organization of the Sergestid Shrimp with the notion of the sustainable administration by the derivation of theoretical model and the simulate analysis of historical data, and the conclusions of analysis are consistency. Furthermore, the study discusses the fishery management policies of TungKung Sergestid Shrimp. I hope the management policies of TungKung producer organization of the Sergestid Shrimp could be popularized in the related industry.
10

MALE REPRODUCTIVE STRATEGIES IN WILD NORTHERN PIG-TAILED MACAQUES (MACACA LEONINA): TESTING THE PRIORITY-OF-ACCESS MODEL

Trebouet, Florian (Allen 01 December 2019 (has links)
Among multi-male, multi-female primate groups, males engage in direct contest competition for access to mates. The priority-of-access model (PoA model) generally predicts that male reproductive success increases with male dominance rank, but the strength of this relationship is expected to decrease with increasing female reproductive synchrony, particularly in seasonally breeding primates. Genetic paternity studies support the model’s predictions, having found a positive relationship between male dominance rank and reproductive success. However, in addition to dominance status and female reproductive synchrony, a number of proximate factors also impact males’ ability to sire offspring, which have not been considered in studies of male reproductive strategies.By integrating behavioral, genetic, morphological, and hormonal analysis as more direct measures of reproductive success in individual males, this dissertation investigated the relationship between male dominance rank and reproductive success and including the proximate factors affecting this relationship in wild northern pig-tailed macaques (Macaca leonina). The main objectives of this study are: 1) to identify the relationships between male dominance rank, male mating success, and male reproductive success, and assess to what extent female synchrony affects these relationships; 2) to identify the proximate factors that may reduce the reproductive success of the top-ranking male and assess variation in male mating tactics related to dominance rank and migration status (i.e., resident males vs. extra-group males); and 3) to evaluate the function of males’ red ornaments that may be used to signal male dominance status (male-male competition) to attract females (female mate choice) or both. The study was conducted at Khao Yai National Park, northeastern Thailand. Systematic data collection on CH group occurred from September 2015-June 2017. The group composition was recorded daily as well as births, deaths, individual emigrations and immigrations, females’ parity status, and the presence of extra-group males (EGMs). Sociosexual data and male-female interactions (i.e., copulations, ejaculatory copulations, consortships, grooming, female proceptive behaviors and receptive behaviors) were recorded during females’ receptive periods. To assess male reproductive success, genetic paternity analyses were conducted on fecal DNA samples collected from 18 adult and subadult males, 22 adult females, and 25 juveniles and infants. To measure red skin coloration of males, hindquarter images were collected non-invasively for seven adult males. From those images, skin color and luminance were computationally quantified to assess variation in male anogenital reflectance. Lastly, fecal samples were collected from nine adult males to assess monthly levels of fecal testosterone by microtitreplate enzyme immunoassay. The distribution of births and matings suggested that northern pig-tailed macaques, at least in this group, are best categorized as moderate seasonal breeders. Indeed, 33-67% of births occurred within a three-month period. Copulation data revealed a positive relationship between male dominance rank and mating success, supporting the predictions of the PoA model. However, the distribution of male reproductive success indicated that: 1) high-ranking males controlled a proportion of paternity much lower than predicted by the PoA model; 2) middle-ranking males controlled a proportion of paternity higher than predicted by the model; and 3) EGMs, not considered in the PoA model, controlled a surprisingly large proportion of paternity despite a low observed mating success. When females were simultaneously receptive, lower-ranking and subadult males engaged in opportunistic and surreptitious copulation and avoided direct competition with higher-ranking males, and most females approached and mated with EGMs out of the resident adult males’ sight. However, one EGM also mated in full sight of resident adult males. This is the first study to report mating and successful paternity by EGMs in a moderately seasonally breeding species.Four male mating tactics were identified: 1) the top-ranking resident male tactic, in which the male competes for the alpha male position to control priority of access to receptive females through long consortships and copulations; 2) the lower-ranking resident male tactic, in which the male copulates opportunistically and surreptitiously out of sight of higher-ranking males mostly during the mating peak; 3) the subordinate EGM tactic, in which the male lives semi-solitarily and copulates opportunistically and surreptitiously, mostly during the mating peaks; and 4) the super-dominant EGM tactic, in which the EGM copulates irrespective of the presence of other males and in full sight of even the highest-ranking resident male. In addition, I found support for female mate choice. Darker and redder males had more mating partners, received more female proceptive behaviors, and were engaged in more consortships and grooming with receptive females. Furthermore, males became redder and darker as female reproductive synchrony increased. Together, these results suggest that male red ornaments exhibited in the male’s anogenital area is attractive to females. Furthermore, behavioral evidence of female mate choice towards EGMs was found. This dissertation provides a comprehensive picture of the complex male mating tactics of northern pig-tailed macaques. To achieve reproductive success, males engage in a diversity of mating tactics, strongly influenced by male dominance rank and the degree of female reproductive synchrony. However, mate-guarding costs, surreptitious copulations by lower-ranking males and EGMs, and female mate choice, need to be included in an extended version of the PoA model to provide stronger predictions of the distribution of male reproductive success in primates.

Page generated in 0.0744 seconds