Critical science gaps impede use of no-take fishery reserves

As well as serving valuable biodiversity conservation roles, functioning no-take fishery reserves protect a portion of the fishery stock as insurance against future over-fishing. So long as there is adequate compliance by the fishing community, it is likely that they will also sustain and even enhance fishery yields in the surrounding area. However, there are significant gaps in scientific knowledge that must be filled if no-take reserves are to be used effectively as fishery management tools. Unfortunately, these gaps are being glossed over by some uncritical advocacy. Here, we review the science, identify the most crucial gaps, and suggest ways to fill them, so that a promising management tool can help meet the growing challenges faced by coastal marine fisheries.     

The paraty artisanal fishery (southeastern Brazilian coast): ethnoecology and management of a social-ecological system (SES)

ABSTRACT: This study intends to give recommendations to the management of Paraty fishery in Brazil through an interplay of local and scientific knowledge. In particular, the objectives are the following: 1) to describe the Paraty fishery; 2) to compare the fishermen's local ecological knowledge with recorded fish landings and previous studies in Paraty; 3) to combine the data on local fishing and on local/Caicara livelihoods with the SES (social-ecological systems) Model. The methods include a systematic survey of fishing in Tarituba and Praia Grande, which are located in the northern end and the central part of the Paraty municipality, respectively. For four days each month, systematic data on catches at landing points were collected, as well as macroscopic gonad analysis data for the fishes Centropomus parallelus and C. undecimalis (snook, robalo), Epinephelus marginatus (grouper, garoupa), Scomberomorus cavalla (King mackerel, cavala), and Lutjanus synagris (Lane snapper, vermelho). Spring and summer are important seasons during which some species reproduce, and the integration of fishing periods for some target species could assist in fishing management through the use of closed seasons. Fishermen could obtain complementary earnings from tourism and from the "defeso system" (closed season including a salary payment) to conserve fishing stocks. The SES model facilitates an understanding of the historical context of fishing, its economic importance for local livelihoods, the constraints from conservation measures that affect fishermen, and the management processes that already exist, such as the defeso. If used to integrate fishing with complementary activities (tourism), such a system could improve the responsibility of fishermen regarding the conservation of fish stocks.     

A comparative study of success and failure of fishery cooperatives in the Aegean, Turkey

This study assessed the performance of fishery cooperatives in six selected fishing areas along the central and southern Aegean coasts of Turkey during the 2002–2003 fishing season, in particular with regard to their stated objectives (e.g. member-fisher satisfaction recognition by fishery management authorities). A total of 127 member-fishers (72% of all active fishers in the study area) as well as fishery cooperative directors were interviewed. The results indicated the various strengths of these cooperatives as well as their limitations. Performance below full potential was due to internal factors such as lack of solidarity and qualified business management skills, as well as external factors relating to weak legislative support by the government, the tax system and the lack of training. However, through their contribution to local society and their function in assisting management bodies, cooperatives play a significant role in Turkish small-scale fisheries. They are therefore in need of further capacity building through specific encouragement from the government, academics, and fishers in order to improve their performance.     

Quantifying the Short-Term Costs of Conservation Interventions for Fishers at Lake Alaotra,Madagascar

Artisanal fisheries are a key source of food and income for millions of people, but if poorly managed, fishing can have declining returns as well as impacts on biodiversity. Management interventions such as spatial and temporal closures can improve fishery sustainability and reduce environmental degradation, but may carry substantial short-term costs for fishers. The Lake Alaotra wetland in Madagascar supports a commercially important artisanal fishery and provides habitat for a Critically Endangered primate and other endemic wildlife of conservation importance. Using detailed data from more than 1,600 fisher catches, we used linear mixed effects models to explore and quantify relationships between catch weight, effort, and spatial and temporal restrictions to identify drivers of fisher behaviour and quantify the potential effect of fishing restrictions on catch. We found that restricted area interventions and fishery closures would generate direct short-term costs through reduced catch and income, and these costs vary between groups of fishers using different gear. Our results show that conservation interventions can have uneven impacts on local people with different fishing strategies. This information can be used to formulate management strategies that minimise the adverse impacts of interventions, increase local support and compliance, and therefore maximise conservation effectiveness.     

三峡水库生态渔业发展策略与关键技术研究分析

针对三峡水库蓄水后水体资源丰富、水生态系统发育尚不完善、支流库湾藻类水华问题较严重、鱼类群落结构有待调控、水生生物资源未有效利用和转化的现状, 阐述了三峡水库生态渔业作为生态系统保护途径和绿色产业的必要性与重要性, 提出了三峡水库生态渔业发展的总体目标与基本原则, 认为三峡水库发展生态渔业应以生态安全保障和水质养护为首要任务, 严格控制外来物种的引种移植, 以土著鱼类自然繁殖保护和捕捞管理为主, 动态调控放流增殖的鱼类种类和数量为辅, 建立以鱼类群落合理配置和食物网结构优化为手段的水库生态系统调控技术体系, 促进高效的物质循环和能量流动, 实现环境保护和渔业增效的双赢。作者围绕渔业放流增殖、野生鱼类资源保护、捕捞管理、局部库区渔业调控、渔业生物控藻、社区渔业协调管理、生态渔业总体规划等方面, 分析了现阶段三峡水库生态渔业的重点研究任务与关键技术,同时建议加强相关生态学理论与方法研究、技术示范和成果应用, 为三峡水库以渔养水、渔-水和谐的综合管理提供决策依据。       

Mobility, expansion and management of a multi-species scuba diving fishery in East Africa

Background

Scuba diving fishing, predominantly targeting sea cucumbers, has been documented to occur in an uncontrolled manner in the Western Indian Ocean and in other tropical regions. Although this type of fishing generally indicates a destructive activity, little attention has been directed towards this category of fishery, a major knowledge gap and barrier to management.

Methodology and Principal Findings

With the aim to capture geographic scales, fishing processes and social aspects the scuba diving fishery that operate out of Zanzibar was studied using interviews, discussions, participant observations and catch monitoring. The diving fishery was resilient to resource declines and had expanded to new species, new depths and new fishing grounds, sometimes operating approximately 250 km away from Zanzibar at depths down to 50 meters, as a result of depleted easy-access stock. The diving operations were embedded in a regional and global trade network, and its actors operated in a roving manner on multiple spatial levels, taking advantage of unfair patron-client relationships and of the insufficient management in Zanzibar.

Conclusions and Significance

This study illustrates that roving dynamics in fisheries, which have been predominantly addressed on a global scale, also take place at a considerably smaller spatial scale. Importantly, while proposed management of the sea cucumber fishery is often generic to a simplified fishery situation, this study illustrates a multifaceted fishery with diverse management requirements. The documented spatial scales and processes in the scuba diving fishery emphasize the need for increased regional governance partnerships to implement management that fit the spatial scales and processes of the operation.     

Nowcasting Intraseasonal Recreational Fishing Harvest with Internet Search Volume

Estimates of recreational fishing harvest are often unavailable until after a fishing season has ended. This lag in information complicates efforts to stay within the quota. The simplest way to monitor quota within the season is to use harvest information from the previous year. This works well when fishery conditions are stable, but is inaccurate when fishery conditions are changing. We develop regression-based models to “nowcast” intraseasonal recreational fishing harvest in the presence of changing fishery conditions. Our basic model accounts for seasonality, changes in the fishing season, and important events in the fishery. Our extended model uses Google Trends data on the internet search volume relevant to the fishery of interest. We demonstrate the model with the Gulf of Mexico red snapper fishery where the recreational sector has exceeded the quota nearly every year since 2007. Our results confirm that data for the previous year works well to predict intraseasonal harvest for a year (2012) where fishery conditions are consistent with historic patterns. However, for a year (2013) of unprecedented harvest and management activity our regression model using search volume for the term “red snapper season” generates intraseasonal nowcasts that are 27% more accurate than the basic model without the internet search information and 29% more accurate than the prediction based on the previous year. Reliable nowcasts of intraseasonal harvest could make in-season (or in-year) management feasible and increase the likelihood of staying within quota. Our nowcasting approach using internet search volume might have the potential to improve quota management in other fisheries where conditions change year-to-year.     

Bio‐economic analysis of the Mar Menor (Murcia,SE Spain) small‐scale lagoon fishery

An integrated fisheries management tool based on a bio‐economic model was applied to the demersal fishery in the Mar Menor coastal lagoon in SE Spain, with the objective of exploring solutions to ensure the sustainability of this activity. The hypothesis is that excess harvesting in recent years by fishers trying to offset growing production costs has led to the inefficient use of lagoon fishery resources. The authors established the basic bio‐economic conditions of the fishery in 2012 by means of field sampling and personal interviews with producers, and analyzed the response of several biological and economic indicators (target species biomass and yield, fleet profits) to a management scenario based on limiting the fishing season of one of the main types of fishing gear (fish traps, locally known as ‘paranzas’). Results show that a reduction in fishing mortality of two overexploited species (Sparus aurata and Lithognathus mormyrus) will help recover the biomass of these stocks by more than 40% as well as increase the economic value of the fishery, with profits increasing by 17% over a 4‐year period.     

Modelling the Spatial Behaviour of a Tropical Tuna Purse Seine Fleet

Industrial tuna fisheries operate in the Indian, Atlantic and Pacific Oceans, but concerns over sustainability and environmental impacts of these fisheries have resulted in increased scrutiny of how they are managed. An important but often overlooked factor in the success or failure of tuna fisheries management is the behaviour of fishers and fishing fleets. Uncertainty in how a fishing fleet will respond to management or other influences can be reduced by anticipating fleet behaviour, although to date there has been little research directed at understanding and anticipating the human dimension of tuna fisheries. The aim of this study was to address gaps in knowledge of the behaviour of tuna fleets, using the Indian Ocean tropical tuna purse seine fishery as a case study. We use statistical modelling to examine the factors that influence the spatial behaviour of the purse seine fleet at broad spatiotemporal scales. This analysis reveals very high consistency between years in the use of seasonal fishing grounds by the fleet, as well as a forcing influence of biophysical ocean conditions on the distribution of fishing effort. These findings suggest strong inertia in the spatial behaviour of the fleet, which has important implications for predicting the response of the fleet to natural events or management measures (e.g., spatial closures).     

Local Ecological Knowledge and Institutional Dynamics for Ecosystem Management: A Study of Lake Racken Watershed, Sweden

The sustainable use of resources requires that management practices and institutions take into account the dynamics of the ecosystem. In this paper, we explore the role of local ecological knowledge and show how it is used in management practices by a local fishing association in a contemporary rural Swedish community. We focus on the local management of crayfish, a common-pool resource, and also address the way crayfish management is linked to institutions at different levels of Swedish society. Methods from the social sciences were used for information gathering, and the results were analyzed within the framework of ecosystem management. We found that the practices of local fishing association resemble an ecosystem approach to crayfish management. Our results indicate that local users have substantial knowledge of resource and ecosystem dynamics from the level of the individual crayfish to that of the watershed, as reflected in a variety of interrelated management practices embedded in and influenced by institutions at several levels. We propose that this policy of monitoring at several levels simultaneously, together with the interpretation of a bundle of indicators and associated management responses, enhances the possibility of building ecological resilience into the watershed. Furthermore, we found that flexibility and adaptation are required to avoid command-and-control pathways of resource management. We were able to trace the development of the local fishing association as a response to crisis, followed by the creation of an opportunity for reorganization and the recognition of slow ecosystem structuring variables, and also to define the role of knowledgeable individuals in the whole process. We discuss the key roles of adaptive capacity, institutional learning, and institutional memory for successful ecosystem management and conclude that scientific adaptive management could benefit from a more explicit collaboration with flexible community-based systems of resource management for the implementation of policies as experiments. Received 26 April 2000; accepted 13 October 2000.     

Lessons Learned from Reconstructing Interactions Between Local Ecological Knowledge, Fisheries Science, and Fisheries Management in the Commercial Fisheries of Newfoundland and Labrador, Canada

Questions centered on the development of local and traditional ecological knowledge and the relationship of that knowledge to the development of conservation and management practices have recently attracted critical attention. We examine these questions with respect to the dynamic commercial fisheries of the Canadian province of Newfoundland and Labrador. The knowledge of fish harvesters coevolves with fishing practices and is embedded in a dynamic socioecological network that extends into and beyond the fisher, fishery households, and communities to include management, technologies, markets, and marine ecological conditions. Changes in these networks have moved knowledge and practices related to fishing in directions defined by policy, science, economic rationality, and new ecological realities. We characterize this movement as a shift along a continuum from local ecological knowledge (LEK) towards globalized harvesting knowledge (GHK) as harvesters become increasingly disconnected from socioecological relationships associated with traditional species and stocks. We conclude with a discussion of how LEK/GHK have interacted over time and space with other knowledge systems (particularly science) to influence management, and suggest that contingent, empirical evaluations of these interactions will provide a fruitful avenue for future interdisciplinary research.

Optimum fishing strategies for Isostichopusfuscus (Echinodermata: Holothuroidea) in the Gulf Of California, Mexico

The Isostichopus fuscus fishery in Mexico was heavily exploited until 1994, when it was closed due to overfishing. However, no information existed on the status of the populations. The fishery was evaluated through an age structured simulation model, and according to our analysis of the stock, the fishery can be feasible and sustainable as long as fishing mortality and age of first catch are optimized. In order to evaluate exploitation strategies, several scenarios were simulated considering different combinations of fishing intensities and ages of first catch. Input data for the model included population parameters, commercial catch and costs and benefits of the fishing operations. Yield production was strongly influenced by the fishing pressure and by the age of first capture. When the first one increased, significant decreases in yield and profits occurred. The best exploitation strategy was these parameters: fishing mortality level F = 0.15, age at first capture t(c) = 4 years, and yielding of approximately 430 tons. However, since the species reproduces for the first time at 5 years, extracting younger specimens would collapse the population. The critical value of fishing mortality was detected at Fc = 0.25. If exceeded, the population tends to exhaustion and the fishery is no longer profitable. In conclusion, I. fuscus fishery is highly vulnerable to overfishing and age of catch. It must be taken into account that the management policies should be considered as pilot and used on a regional basis. Continuous monitoring of the stock, control of the number of fishing licenses and extracting only specimens 5 yeasr-old and older (around 20 cm and >400 g), will allow the populations to recover from fishing activities. Rev. Biol. Trop.     

Non-management of Natural Resources: The Case of Inland Fisheries in the Mayan Zone,Quintana Roo,México

This study explores the management of inland fisheries on common lands (ejidos) within the Mayan Zone of Quintana Roo, Mexico. Qualitative survey data are used to examine whether there are (a) ongoing fishery conservation activities; (b) local caretakers of fishing sites; (c) restrictions on where fishing can take place; and (d) particular groups of individuals who lack the right to fish within the ejidos. Results indicate that in contrast to other local resources, fisheries in the ejidos have less defined use rights, being viewed as largely “open access”. In particular, most feel that outsiders can fish in an ejido if they abide by local rules (notably not damaging the local water bodies, asking consent to fish, and having a friend or relative in the community). However, there are within-community differences in views concerning management and conservation, with those more dependent on fishing being more likely to support exclusion of outsiders.     

A comparative study on socio-economic indicators and viability in small-scale fisheries of six districts along the Turkish coast

The study evaluates the status of small-scale fishermen and fishing operations, using socio-economic indicators and economic viability estimates in six selected fishing areas of Turkey during the 2002–2003 fishing season. Fifty-six percent of all small-scale fishing boats investigated achieved a positive net profit, fully recovering their operational and investment costs. Considering the viability of the fishery, 56% can be considered as economically viable. Percentages of negative gross cash flow (GCF) for each of the vessels in the district was 56% in Foça, 57% in Karaburun, 15% in Mordoğan, 16% in Akyaka, 65% in Akçapınar, and 44% in Marmaris. On the other hand, when sustainability is defined with more than an economic performance ratio of 10%, only 41% of the small-scale fishing vessels seem to have shown favourable results. Criteria such as comparatively higher catch, smaller crew size and lower labour costs, structure of the fishery or misreporting might have had a slight role in affecting the overall results which indicate that livelihood and economic viability are threatened by irregular and relatively low income levels in the small-scale fisheries sector. Given the economic conditions of small-scale fishing communities, it is suggested that all persons concerned at the community, industry and government levels should take a fresh look at the problem of sustainability. As such, more attention needs to be paid to the fishery management option by looking at performance data and having long-term monitoring of the socio-economic indicators.     

In search of traditional bio-ecological knowledge useful for fisheries co-management: the case of jaraquis <Emphasis Type="Italic">Semaprochilodus</Emphasis> spp. (Characiformes,Prochilodontidae) in Central Amazon,Brazil

The jaraquis (Semaprochilodus spp.) are the most abundant group in the fishing landing in Manaus. However, just command and control management strategies have been used by the fishery governmental agency in the region without the power to enforce centralized decisions. The fishermen and their culture represent a source of information on dynamics of the resources and aquatic environments, fundamental in making possible the co-management of the fishing resources. The present study aims to contribute to management through identification of common information available in scientific and traditional knowledge about the jaraquis' bio-ecology. There were 57 semi-structured interviews recorded with fishermen of Manaus and rural areas of Manacapuru in 2002 concerning biological and ecological aspects. Similarity was observed between scientific and traditional knowledge in the following items: size of first sexual maturation, spawning type, parental care, trophic relationships and migratory behavior, as well as in some aspects of the mortality and growth of the species. However, there was less ethnoicthyological information on fecundity and the determination of the age and growth of adult fish. Common information would be used preferably by agencies to start an effective and technical dialogue with commercial and riverine fishermen to design management plans in a decentralized strategy.     

Drivers of the Distribution of Fisher Effort at Lake Alaotra,Madagascar

Understanding how fishers make decisions is important for improving management of fisheries. There is debate about the extent to which small-scale fishers follow an ideal free distribution (IFD) – distributing their fishing effort efficiently according to resource availability rather than being influenced by social factors or personal preference. Using detailed data from 1800 fisher catches and from semi-structured interviews with over 700 fishers at Lake Alaotra, the largest inland fishery in Madagascar, we show that fishers generally conform to IFD. However, there were differences in catch: effort relationships between fishers using different gear types as well as other revealing deviations from the predictions of IFD. Fishers report routine as the primary determinant of their choice of fishing location, explaining why they do not quickly respond to changes in catch at a site. Understanding the influences on fishers’ spatial behaviour will allow better estimates of costs of fishing policies on resource users, and help predict their likely responses. This can inform management strategies to minimise the negative impacts of interventions, increasing local support for and compliance with rules.     

Biodiversity Offsets: A Cost-Effective Interim Solution to Seabird Bycatch in Fisheries?

The concept of biodiversity offsets is well established as an approach to environmental management. The concept has been suggested for environmental management in fisheries, particularly in relation to the substantial numbers of non-target species--seabirds in particular--caught and killed as incidental bycatch during fishing activities. Substantial areas of fisheries are being closed to protect these species at great cost to the fishing industry. However, other actions may be taken to offset the impact of fishing on these populations at lower cost to the fishing industry. This idea, however, has attracted severe criticism largely as it does not address the underlying externality problems created by the fishing sector, namely seabird fishing mortality. In this paper, we re-examine the potential role of compensatory mitigation as a fisheries management tool, although from the perspective of being an interim management measure while more long-lasting solutions to the problem are found. We re-model an example previously examined by both proponents and opponents of the approach, namely the cost effectiveness of rodent control relative to fishery area closures for the conservation of a seabird population adversely affected by an Australian tuna fishery. We find that, in the example being examined, invasive rodent eradication is at least 10 times more cost effective than area closures. We conclude that, while this does not solve the actual bycatch problem, it may provide breathing space for both the seabird species and the industry to find longer term means of reducing bycatch.     

Estimation of population parameters and their application to the development of fishery management models in two African rivers

The dynamics of fish populations in two African rivers are being investigated with a view to developing fishery management models for tropical non-floodplain rivers. Preliminary work was carried out in the Rufiji River, East Africa, to establish growth and mortality rates along with L _∞ and K for six species in a river where fishing mortality is zero. These parameters, derived from scale-reading and length frequency analysis, also allowed the development of phased management plans for the fishery resulting from impoundment.
A subsequent investigation has begun on a West African river, the Taia in Sierra Leone, to pursue observations over four seasons, two of which are now complete. A systematic daily sampling programme is being carried out of the whole community, to accumulate similar but more extensive data to those obtained previously. In the Taia, however, fishing mortality must also be estimated from catch surveys, and analysis is carried out using the recently developed ELEFAN programs which can be compared with results obtained by other methods such as scale-reading.     

浅水湖泊四种渔具捕捞选择性及对鱼类群落影响比较研究

了解不同种类和大小的鱼类对各种捕捞方式的脆弱性, 对于制定最佳的捕捞策略和合理开发鱼类资源至关重要。研究从渔获物组成、捕捞效率和个体大小等方面, 对长江中游典型湖泊牛山湖的四种渔具(网簖、刺网、电捕和鸬鹚)的捕捞选择性进行了比较分析。使用相对重要性指数(IRI)评价渔具捕捞对鱼类物种的选择性, 同时通过计算渔获物的平均营养水平(MTL)和饵料鱼与凶猛性鱼类的重量比, 分析捕捞对鱼类群落营养结构的潜在影响。结果表明, 网簖和电捕捕获的鱼类种数多、体长范围广, 对鱼类资源的破坏性最大, 应当加以限制或废除; 鸬鹚是捕获鳜(尤其是高龄鳜)的一种有效方式, 但对幼鳜和其他幼鱼也有较大损害, 应控制其捕捞强度; 刺网主要捕获几种经济鱼类, 并可平衡捕食者和饵料鱼之间数量关系, 是利用鱼类资源的一种较好方式, 关键在于对刺网网目大小和捕捞强度的限制。建议湖泊捕捞应从单一物种转向多物种综合管理, 并考虑物种之间的营养生态关系, 以更好地保护和可持续利用渔业资源。