The state of the Northeast Atlantic fisheries in recent years has highlighted implementation as the Achilles heel of modern fisheries management: discards, unreported or misreported landings are in ...many cases recognised to effectively subvert sound conservation goals. Implementation is thus a key factor in avoiding fisheries crises. While social science literature on fisheries management has tended to regard the implementation of resource conservation policies as a question of effective enforcement, this book seeks to widen the perspective taken on implementation in fisheries management. The cases presented in this volume addresses legal, administrative, and political challenges regarding implementation of resource conservation policies. The book addresses problems relating to goal achievement, but also causes of deliberate change of political goals during implementation. Fisheries management systems are embedded in inert social structures and natural conditions that vary among different states. Consequently, the book takes a historical and comparative approach, describing the historical developments of national implementation systems and the conditions that shaped their development. It thus seeks to explain why national fisheries management systems have evolved differently, focusing on Norwegian, Faeroese, and EU/Danish management systems. The descriptive and explanatory outlines are accompanied by qualitative assessments of the systems effectiveness as tools for collective action. Written for:Fisheries professionals: fishermen, scientists, managers, communicators and educators; students of fisheries science; environmentalists and conservationists
Mycteroperca bonaci (black grouper) is one of the most sought species of grouper along its entire distribution, being a prime target for demersal line fisheries because of its high commercial value. ...Nonetheless, because of population declines the species is considered near threatened according to the IUCN red list. The present study aimed to determine the population parameters of M. bonaci, including growth, reproduction and mortality, and thus contributes to measures towards its conservation and management in the southwestern Atlantic. The sampling area is in the North Brazil Shelf, off Maranhão State, an area of intense fisheries development and yet poorly known. The large continental shelf harbours unique coral reef formations and has been declared an ecologically or biologically significant marine area (EBSA). Sampling on landing sites was carried out monthly between May 2017 and January 2019. A total of 137 black grouper specimens were sampled from commercial landings of artisanal fisheries. The size of the specimens ranged from 44 to 157 cm, and the weight varied from 0.976 to 54 kg. The length–weight was established: log(TW) = −11.26 + 3.01log(TL). Histological analysis of the gonads confirmed only the presence of female individuals, and the occurrence of individuals in the sexual transition was not recorded. Higher GSI values and higher frequency of spawning capable staged individuals occurred during the months of June to August, indicating spawning peaks. The estimated age of sexual maturity A50 for females was 4.62 years (x_ 93 cm−TL). The growth parameters for the Von Bertalanffy model were TL∞ (cm): 185.5, k: 0.04, t0 (year): −4.75 (t0 not fixed) and TL∞ (cm): 141, k: 0.11 (t0 = 0 fixed). The total estimated mortality rate (Z) according to catch length presented a Z value = 0.11, and the natural mortality was M = 0.04 year−1. This is the first study on the age and growth of M. bonaci in the SWA, a region where the species is considered as endangered according to Brazil's red list regional assessment. Only females were present in the samples, results that suggest either differential capturability of sexes because of distinct patterns of behaviour or distribution or an effect of selective mortality upon larger and older individuals, as the species is described as a protogynous hermaphrodite. This indicates the need to closely manage this population to avoid collapses. Recovery plans that have been planned by the Brazilian government but not yet implemented for the species must be put into practice to avoid progressive decline as fisheries target more remote areas.
Governance of social-ecological systems is a major policy problem of the contemporary era. Field studies of fisheries, forests, and pastoral and water resources have identified many variables that ...influence the outcomes of governance efforts. We introduce an experimental environment that involves spatial and temporal resource dynamics in order to capture these two critical variables identified in field research. Previous behavioral experiments of commons dilemmas have found that people are willing to engage in costly punishment, frequently generating increases in gross benefits, contrary to game-theoretical predictions based on a static pay-off function. Results in our experimental environment find that costly punishment is again used but lacks a gross positive effect on resource harvesting unless combined with communication. These findings illustrate the importance of careful generalization from the laboratory to the world of policy.
A debate is emerging over the extent to which privatization of fishery resources is socially desirable. The "pessimists" argue that there are strict limits to socially optimal privatization of such ...resources. The "optimists" maintain that there are no effective limits to privatization and that the decades old fear that privatization could, in some cases, lead to resource extinction are of theoretical interest only. We argue here that these fears are, regrettably, not baseless and that there are definite limits to socially desirable privatization. We discuss means by which such limits could be identified on a fishery-by-fishery basis.
Climate change has detrimental impacts on the ocean such as ocean acidification, the occurrence of extreme weather, increasing frequency of storms, and sea level and temperature rise, which will ...threaten the marine ecosystem existence and threaten the marine economic potential. Indonesia, with 6.4 million km2 area of waters, hold enormous fisheries potential wealth and enormous potential economic value. Data from the Marine and Fisheries Ministry notes that the marine economic potential reaches IDR 3000 trillion and there only IDR 291.8 trillion of the total potency that already gained. Sustainable fisheries development must be in accordance with the development principles that benefit the present generation but still pay attention to sustainability for future generations. Blue economy policies and programs become the right and effective approach for marine development to encourage optimal and sustainable utilization and exploitation of fisheries resources. This research is a legal research by using statute approach to relevant legal materials. This study aims to integrate the blue economy principle in to marine and fisheries policies and reconstruct the existing policies. The result of this study is a proposed model of blue economy-based policy to get a sustainable national marine and fisheries management.
For management efforts to succeed in Caribbean fisheries, local fishers must support and be willing to comply with fishing regulations. This is more likely when fishers are included in a stock ...assessment process that utilizes robust scientific evidence, collected in collaboration with fishers, to evaluate the health of fish stocks. Caribbean parrotfishes are important contributors to coral reef ecosystem health while also contributing to local fisheries. Scientifically robust stock assessments require regional species-specific information on age-based key life history parameters, derived from fish age estimates. Evaluation of the accuracy of age estimation methods for fish species is a critical initial step in managing species for long-term sustainable harvest. The current study resulted from a collaborative research program between fish biologists and local fishers investigating age, growth, and reproductive biology of the seven parrotfish species landed in U.S. Caribbean fisheries; specifically, we validated age estimation for stoplight parrotfish Sparisoma viride and queen parrotfish Scarus vetula. This is the first study to directly validate age estimation for any parrotfish species through analysis of Δ14C from eye lens cores. Our age estimation validation results show that enumeration of opaque zones from thin sections of sagittal otoliths for a Sparisoma and a Scarus species provides accurate age estimates. The oldest stoplight parrotfish and queen parrotfish in the Δ14C age estimation validation series were 14 y and 16 y; while the oldest stoplight parrotfish and queen parrotfish we aged to-date using the Δ14C validated age estimation method were 20 y and 21 y, respectively. Fish longevity (maximum age attained/life span) is a key life history parameter used for estimation of natural mortality, survivorship, and lifetime reproductive output. Past reviews on parrotfishes from the Pacific and Atlantic concluded that most Caribbean/western Atlantic parrotfish species are relatively short-lived with estimated maximum ages ranging from 3-9 y. However, information from our collaborative research in the U.S. Caribbean combined with recently published age estimates for Brazilian parrotfish species indicate that many western Atlantic parrotfishes are relatively long-lived with several species attaining maximum ages in excess of 20 y.
The Baltic Sea is one of the most eutrophied seas in the world, facing challenges with both hypoxia and algae blooms. In this study we analyse the effect of using different fishery policy instruments ...to reduce nutrient loads by removing fish biomass from the ecosystem. The study covers Danish, Finnish and Swedish pelagic fisheries. We distinguish between a private optimum maximising the net present value from fishing and a social optimum including the positive externality of removing nutrients. A dynamic bio-economic model, FishRent, is used to estimate the effect of three policy scenarios: Fisheries regulation using individual transferable quotas (ITQ); Economic compensation provided to fishers for reducing nutrients; and Environmental regulation maximising sustainable catches. The results show that the highest social welfare gain is achieved by maximising catch volumes while having a flexible system for quota trade within the fishing sector. The social welfare gain from the positive externality of the extra fish landed in this case outweighs the private loss of not fishing at the optimal individual level (maximum economic yield).
•Fisheries contribute to removal of nutrients in the eutrophied Baltic Sea•Combining fisheries policy instruments, aiming at utilizing total allowable catches maximize the overall welfare to society•The welfare gain from the positive externality outweighs the private loss of not fishing at the optimal individual level•Fishing at Maximum Sustainable Yield generate the highest benefit to society, taking into account the positive externality•The policy scenarios are modeled using the dynamic bio-economic model FishRent
Offshore aquaculture plays an important role in China's marine fishery economy. The research on the extraction of offshore aquaculture areas based on remote sensing technology is of great ...significance for the regulation of offshore fishery resources and the protection of the marine ecological environment. This paper uses the Gaofen-2 series multispectral remote sensing image to extract the offshore aquaculture areas of Lianyungang City. We use the optimum index factor to extract the spectral features of the aquaculture areas and the grey-level co-occurrence matrix to extract their texture features. We use the Bhattacharyya distance to select the spatial and spectrum features and construct the characteristic data set of the aquaculture areas. In this paper, we propose a method to construct a uniform distributed disturbance term to optimize the cross entropy loss function. We employ it in the three-dimensional convolutional neural network (3D-CNN) model, extract the extended feature data set of aquaculture areas, and input it into the radial basis function support vector machine (RBF-SVM) classifier for classification. Within the study area of 150 km
2
, the experimental results show that the extraction model has high extraction accuracy and strong spatial migration despite complex water backgrounds. The F
1
-score values in the training area and the four random test areas were 0.939 or above for 2017 data. In addition, the extraction model also has stable time migration. We used the extraction model on remote sensing data for the same study area in 2018 and 2019. The F
1
-scores for all test areas are 0.866 or higher. Therefore, the model proposed in this paper is suitable for the extraction of large-scale and multi-temporal offshore raft aquaculture areas from remote sensing images.
PDF
