Networks of capital: Reframing knowledge in the Namibian hake fishery

This paper explores the failures of the quota allocation system in the hake fishery in Walvis Bay, Namibia through an examination of the complex processes that link commodities, labour, production, markets, and knowledge in the industrial setting. The relationships between state regulations and public nature point to a specific engagement in which nature is divided, distributed, and owned, namely through the market driven prospects of transferable quotas. This article examines fishing quota as a set of relations that links the transformation of fish from biological organism to global product and thus weaves science, the state, markets, and social relationships into an entanglement of different forms of capital. In this context, the tension between the quota holder, the value of that quota, and their participation in the industry reflects a complex network of capital mediated through various strategies. Based on ethnographic research in the Namibian trawl sector, this article surfaces these modes of capital in the dynamics of the fishing operations. As such, the fishing industry, the company that holds the fishing rights, the government׳s role in quota allocations, the vessels, gear, and technologies, and the relationships and roles of the crewmembers and skippers׳ knowledge all contribute to a particular formulation of fishing practices. Fisher׳s knowledge in industrial fishing practices becomes a site in which to explore the consequences of ITQs that may also begin to destabilise the neoliberal business model for fisheries in times of crisis.     

Measuring fishery profitability: An index number approach

Tracking the financial well-being of vessels that depend on a marine fishery resource is an important function of regulators. This research demonstrates how simple indices can be constructed and utilized to track the economic well-being of vessels operating in the Northeast (USA) Multispecies (Groundfish) Fishery. The indices, which use both public and private data, can separately track trends in inputs, outputs, and prices. For the Northeast Multispecies Fishery, the indices reveal that the economic well-being of the groundfish fleet has improved under catch share management through gains in productivity.     

Statistical fraud detection in a commercial lobster fishery

In this study we introduce the first step towards a statistical model for the reliability of fisheries data. We applied Benford's Law to catch data from the Atlantic Canadian lobster (Homarus americanus) fishery's lobster fishery areas (LFAs) 33 and 34 and compared our results to those using observations from the “grey zone” (a highly regulated lobster fishery shared by Canada and United States) and a fishery with a different regulatory regime (snow crab, Chionoecetes opilio). Non‐conformity with Benford's Law is often considered as an indicator of human manipulation of accounting data. We found that observations from the grey zone conformed to the distribution predicted by Benford's Law, whereas observations from snow crab and both lobster fishery areas did not conform.     

Offshore wind capital cost estimation in the U.S. Outer Continental Shelf—A reference class approach

Offshore wind power developed rapidly in Northern Europe in the first decade of the 21st century and is expected to spread to Southern Europe, North America and Asia before 2020. To date, no projects have been built offshore North America because of the high development costs and economic risk and uncertain profitability. The purpose of this paper is to review the development cost of constructing offshore wind farms to inform the U.S. market. The capital expenditures of a reference class of 18 European wind farms constructed after 2005 with monopile foundations are normalized to proxy U.S. capital cost. Regression models are developed to investigate the physical features that influence expenditures. U.S. capital costs are expected to range between $4 and $5.6 million/MW for projects built between 2012 and 2015. Capital costs increase with increasing water depth and steel prices. For most farm components, capital expenditures are expected to be similar in Europe and the U.S., but the installation markets differ and this may impact the reliability of the reference class approach.     

A small core fishery:: a new approach to fisheries management

A new approach to fisheries management is suggested. Recognizing the great uncertainty and variability that affects the supply of fish, combined with the immobility of capital and labor in the industry, a small core fishery should be maintained with the capacity to catch only the quantity of fish that it would be safe to catch as the stock approaches the lower limits of its natural cycle. When fish are abundant, the excess would be auctioned to risk takers who have neither a permanent commitment to, nor multi-year fishing rights in, the fishery.     

Managing sino-ghanaian fishery relations: A political ecology approach

A global recurring challenge for marine managers and policy makers is the effective management of fisheries conflicts. This study demonstrates the usefulness of a political ecology approach in understanding the complexity of conflict in increasingly internationalized national fisheries. By doing so it aims to provide an alternative approach to the environmental security perspectives, predicated on scarcity narratives, that often underpin policy on fishery conflicts. Using a localised example of industrial Chinese and local artisanal fishermen conflict in Ghana, this paper reveals a complex account of contesting ‘access’ to resources, in material and nonmaterial terms, that moves beyond an ‘absolute scarcity’ driven narrative. The conflict is shown to be one, in part, focussed around spatially fixed areas as well as moral claims of correct ways of fishing that reflect social tensions within the local fishing community. Both aspects show long term motivations to keep resource access, rather than being concerned with in the moment struggles over scarce resources. This work also highlights the existence of cooperation between groups of artisanal fishermen involved in transhipment with Chinese fishermen, revealing the complex nexus of winners and losers produced by environmental, social and political factors. In sum, policy must acknowledge that conflict is rarely produced purely by scarcity, and that broader social and political factors often combine in a variety of forms to produce localised conflict. If these complexities are ignored, fisheries policy runs the risk of unintentionally exacerbating conflicts and disadvantaging those who it aims to help.     

Understanding socio-ecological drivers of spatial allocation choice in a multi-species artisanal fishery: A Bayesian network modeling approach

Effective management of artisanal fisheries requires understanding fishers, their behaviors, and the drivers that underpin their choices. Behavioral drivers are critical links in understanding the interactions between social and ecological systems and can help inform effective management approaches. A Bayesian Belief Network modeling approach was used to investigate a diverse range of qualitative and quantitative social and ecological drivers of spatial location choice in a multi-species artisanal dive fishery in Costa Rica. Empirical and observer data used to populate the BBN showed the influence of economic factors, environmental conditions as well as social interactions on the decision-making process of spatial location choice. Good governance scenarios represented by Responsible Fisheries Marine Areas Management were analyzed for both hookah and free diving methods to assess the effects of responsible fishing on the fishers and the fishery. Model based-scenario analysis suggests that management interventions should consider the fisher's potential behavioral responses in the context of environmental variability, dependence on cultural assets, and food security. The results show that there is a need to understand fisher's decisions based on broad socio-ecological system understanding and consider the environmental outcomes alongside food security and the cultural significance of different marine species to fishing communities.     

A voluntary reduction in the commercial catch of rock lobster (Jasus edwardsii) in a New Zealand fishery

We describe the development and application of a management procedure (decision rule) that resulted in a voluntary reduction in the commercial catch of spiny rock lobster (Jasus edwardsii) in the lower east coast of North Island of New Zealand. The management procedure was developed from an accepted assessment of the CRA 4 (Wellington‐Hawke's Bay) fishery, which used an integrated length‐based assessment model fitted to commercial fishery catch‐per‐unit‐effort (CPUE) biomass indices, commercial length‐frequency data, and tag‐recapture data. The assessment model had been Bayesian, and used the joint posterior distribution of parameters to predict the effect of 384 alternative harvest control rules on the future size of the CRA 4 stock. The harvest control rules all used CPUE as their input, and generated annual changes in catch, which were then simulated by the population dynamics of the operating model. Uncertainty was added to evaluations through observation error, added to the simulated CPUE observations, and stochastic serial auto‐correlation variation in recruitment. We describe how this management procedure was used to effect a voluntary reduction in catch to address the problem of a rapidly declining population.     

低渗油藏采收率确定新方法

通过对油藏相渗曲线的归一化处理,利用达西定律理论,建立采油指数与含水率的关系;再通过油藏确定的单井经济极限采油量和油藏极限生产压差求出极限采油指数,从而得到极限含水率;最后以最终水驱体积波及系数与储层退汞效率计算出采收率。并以低渗透油藏为实例验证了该方法的正确与适用性,说明该方法对油田开发中确定低渗油藏采收率具有科学的指导意义。     

Transdisciplinary co-operation for an ecosystem approach to fisheries: A case study from the South African sardine fishery

Integrative approaches that involve natural and social scientists are needed to manage fisheries, but these are difficult to achieve. The process of developing a prototype, knowledge-based, electronic decision support tool for the South African sardine Sardinops sagax fishery provided a platform for fostering collaboration and achieving active participation of many stakeholders. The aim of the decision support tool is to assist managers in evaluating how effectively an ecosystem approach to fisheries (EAF) has been implemented for this fishery. The collaborative process involved a series of meetings during which knowledge was elicited from fisheries scientists, social scientists, resource managers and fishing industry representatives. Conceptualisations of the different stakeholder perspectives were developed in terms of objectives and indicators following the hierarchical tree approach recommended by FAO. This paper describes the collaborative process. Hierarchies of objectives, indicators and data sets for the human dimension of an EAF in the South African sardine fishery are introduced. The value of a transdisciplinary approach towards an EAF in South Africa is discussed.     

东海区底拖网渔业主要经济鱼类渔业生物学的初步研究

根据1997~2000年东海区底拖网渔业资源调查资料,分析了18种主要经济鱼类的渔业生物学特征,运用体长频率法估算了von Bertalanffy生长参数、总死亡系数、自然死亡系数、捕捞死亡系数和开发率。结果表明,大部分鱼类已出现个体小型化,15种鱼类的开发率过高,处于超额开发状态,其中,4种为重度超额开发,开发率大于0.8,7种为中度超额开发,开发率介于0.7~0.8之间,4种为轻度超额开发,开发率为0.5~0.7。建议加强保护和管理,以利于鱼类资源的可持续利用。     

Maximum run-up,breaking conditions and dynamical forces in the swash zone: a boundary value approach

On the basis of the approximate analytical solution for the nonlinear shallow water equations of Antuono and Brocchini [M. Antuono & M. Brocchini, The boundary value problem for the nonlinear shallow water equation, Stud. Appl. Maths, 119, 71–91 (2007).], we propose useful regression curves for the prediction of maximum run-up and dynamical forces in the swash zone on a frictionless, uniformly sloping beach. For the first time the dependence of the results on both the wave height and the wave steepness is analyzed in detail providing formulae able to describe a wide class of wave inputs. Finally, the regression formulae are validated through comparison with maximum run-up laws and breaking conditions already available in the literature, the present model results appearing to better account for nonlinear effects.     

Sustainable development: Social outcomes of structural adjustments in a South Australian fishery

The assessment of sustainable development is a relatively recent advent in policy and the evaluation of industry structural adjustments. Although the elements of economic and environmental assessment have been relatively well developed and accepted, the effective inclusion of ‘social’ aspects in assessments of sustainable development are still being grappled with.     

Adaptation in a time of stress: A social-ecological perspective on changing fishing strategies in the Canadian snow crab fishery

Recent scholarship has focused attention on the dynamics and management of marine social ecological systems and on the need for developing a deeper understanding of the fishing strategies of fish harvesters. This includes an understanding of how a broad range of factors influence the strategies of those at the ‘center’ of marine social-ecological interactions. This paper reports on the findings of a survey of snow crab (Chionoecetes opilio) fishers in Southeastern Labrador conducted at a time (2005) of significant stress in the fishery. Results highlight that snow crab fishers are embedded in a social-ecological system and that shifts in fishing strategies in times of stress are a product of adapting to a dynamic, interactive set of factors that have social, economic, ecological and management aspects. Important differences between fleet sectors (larger and smaller vessels) as well as processes of learning are also described. The article concludes with a discussion of the implications for management and the utility of a holistic social-ecological perspective.     

A software tool for monitoring legal minimum length of landings: Case study of a fishery in southern Spain

The regulation of minimum legal size (MLS) of catches is a tool widely applied in the management of fisheries resources, although the MLS does not always coincide with the length at first maturity (LFM). The optimization of this management tool requires a series of quality control in fish markets and transportation. A software application has been developed to make the control of the landings of several target species easier and faster. In order to test and make this tool operational, six species of commercial interest were selected: four species of fish and two species of bivalves. It is proposed to estimate the proportion of illegal specimens in the studied lot from the proportion of illegal individuals found in the samples taken from this lot. The input data for the application are the minimum legal size (MLS) of the species and the total length (TL) of each specimen sampled. The output data is a statistical summary of the percentage of specimens of size less than the legal minimum (TL≤MLS) within different confidence intervals (90%, 95% and 99%). The software developed will serve as a fast, efficient and easy to manage tool that allows inspectors to determine the degree of compliance on MLS control and to make a decision supported by statistical proof on fishing goods.     

Determining primary and companion species in a multi-species fishery: Implications for TAC setting

The use of ITQ management in multi-species fisheries has been the subject of much debate and the complexities and difficulties of managing multi-species fisheries are well known. A major problem is that the species mix in fishery catches may not necessarily match the mix in combined TACs or in quota holdings. While a number of solutions have been proposed or implemented to improve transferability of quota and other incentives to reduce over-quota fishing and discarding, it is surprising that there has been little focus on TAC-setting itself and coordinating this across multiple species/stocks as a means of dealing with some of these issues. In this paper, data were analysed from the trawl sector of the Australian Southern and Eastern Scalefish and Shark Fishery to determine the relationship between primary species and companion species and the implications this has for TAC setting. The primary species is the species being considered when setting an individual species TAC. The companion species are ones that should also be considered when setting the TAC of the primary species, because a considerable proportion of the primary species catch is taken as a companion species non-target catch. The target species in each fishing operation was determined and was used to characterize recent multi-species catch data into primary and companion components. This approach provides an empirical means to examine the impact of individual species TAC decisions across all of the quota species in a fishery.     

Size matters: Short term loss and long term gain in a size-selective fishery

The maximum sustainable yield concept (MSY) and the ecosystem approach to fisheries management (EAFM) have been recently adopted by the European Commission with the objective to achieve, over the long term, the highest possible sustainable yield from a given exploited stock. In this context, a fishing mortality MSY reference level (i.e., F_MSY) should be defined, taking into account recruitment, growth and natural mortality under current or recent ecosystem conditions. Thus, F_MSY is used as a generic term for a robust estimate of a fishing mortality level that is associated with high sustainable yield in the long term, assuming the current harvesting regime in terms of size selectivity. In this study, using the Eastern Baltic cod as an example, we challenge this rather simplified view showing that by using a different harvest selectivity and thus changing the size range of harvested cod, it is possible to largely increase the yield and revenue from the fishery compared to the fishing mortality stipulated in the management plan (i.e., F_MSY), while assuring sustainable high yield in the long term. Thus, implementing the MSY concept in terms of fishing mortality but neglecting selective harvesting effects will not achieve high long term sustainable yield for Eastern Baltic cod. The combination of size selective harvesting and economic reasoning may offer an important tool for the management of marine resources by potentially providing a common currency for the different stakeholders and offer guidance to achieve long term sustainability and human well-being. This would represent the natural step forward in the implementation of EAFM and MSY concepts.     

Bridges to best management: Effects of a voluntary bycatch avoidance program in a mid-water trawl fishery

The catch of non-target species or discarding of target species (bycatch) in commercial fisheries can result in negative species level and ecosystem wide impacts as well as adverse social and economic effects. Bycatch has become one of the foremost, global issues of fishery managers and conservationists, especially when the non-target species is from a protected or threatened population. However, the impact and spatial distribution of bycatch is frequently unknown making it difficult to develop effective, justifiable mitigation regulations. This challenge is exemplified by the bycatch of river herring (alewife, Alosa pseudoharengus, and blueback herring, A. aestivalis) and American shad (A. sapidissima) in the northwest Atlantic mid-water trawl fishery targeting Atlantic herring (Clupea harengus) and Atlantic mackerel (Scomber scombrus). As an alternative to immediate management action, a voluntary bycatch avoidance program was established through an industry, state government, and university partnership. Here the program is described and its impact is evaluated by comparing fleet behavior and bycatch prior to and during the program. The combined results suggest that consistent communication, facilitated by the avoidance program, positively influenced fishing habits and played a role in the approximately 60% decrease in total bycatch and 20% decrease in the bycatch ratio observed during the program. However, the success of small scale move-along strategies to reduce bycatch ratios varied greatly in different areas of the fishery and years. This suggests the program is best viewed as an intermediate or complimentary solution. Overall, this project exemplifies of how collaborative programs can help alleviate difficult management scenarios.