Lessons for resource conservation from two contrasting small-scale fisheries

Small-scale fisheries present challenges to management due to fishers’ dependency on resources and the adaptability of management systems. We compared social-ecological processes in the sea cucumber fisheries of Zanzibar and Mayotte, Western Indian Ocean, to better understand the reasons for resource conservation or collapse. Commercial value of wild stocks was at least 30 times higher in Mayotte than in Zanzibar owing to lower fishing pressure. Zanzibar fishers were financially reliant on the fishery and increased fishing effort as stocks declined. This behavioral response occurred without adaptive management and reinforced an unsustainable fishery. In contrast, resource managers in Mayotte adapted to changing fishing effort and stock abundance by implementing a precautionary fishery closure before crossing critical thresholds. Fishery closure may be a necessary measure in small-scale fisheries to preserve vulnerable resources until reliable management systems are devised. Our comparison highlighted four poignant lessons for managing small-scale fisheries: (1) diagnose the fishery regularly, (2) enable an adaptive management system, (3) constrain exploitation within ecological limits, and (4) share management responsibility.     

Marine fisheries in Tanzania

Fishery resources are a vital source of food and make valuable economic contributions to the local communities involved in fishery activities along the 850 km stretch of the Tanzania coastline and numerous islands. Small-scale artisanal fishery accounts for the majority of fish catch produced by more than 43 000 fishermen in the country, mainly operating in shallow waters within the continental shelf, using traditional fishing vessels including small boats, dhows, canoes, outrigger canoes and dinghys. Various fishing techniques are applied using uncomplicated passive fishing gears such as basket traps, fence traps, nets as well as different hook and line techniques. Species composition and size of the fish varies with gear type and location. More than 500 species of fish are utilized for food with reef fishes being the most important category including emperors, snappers, sweetlips, parrotfish, surgeonfish, rabbitfish, groupers and goatfish. Most of the fish products are used for subsistence purposes. However, some are exported. Destructive fishing methods such as drag nets and dynamite fishing pose a serious problem as they destroy important habitats for fish and other organisms, and there is a long-term trend of overharvested fishery resources. However, fishing pressure varies within the country as fishery resources are utilized in a sustainable manner in some areas. For this report more than 340 references about Tanzanian fishery and fish ecology were covered. There are many gaps in terms of information needed for successful fishery management regarding both basic and applied research. Most research results have been presented as grey literature (57%) with limited distribution; only one-fifth were scientific publications in international journals.     

Satisfaction with fishing and the desire to leave

Predicting who may leave a fishery is an important consideration when designing capacity reduction programs to enhance both ecological and economic sustainability. In this paper, the relationship between satisfaction and the desire to exit a fishery is examined for the Queensland East Coast Trawl fishery. Income from fishing, and changes in income over the last 5 years, were key factors affecting overall satisfaction. Relative income per se was not a significant factor, counter to most satisfaction studies. Continuing a family tradition of fishing and, for one group, pride in being a fisher was found to be significant. Satisfaction with fishing overall and the challenge of fishing were found to be the primary drivers of the desire to stay or leave the fishery. Surprisingly, public perceptions of fishing, trust in management and perceptions of equity in resource allocation did not significantly affect overall satisfaction or the desire to exit the fishery.     

Climate change,fisheries management and fishing aptitude affecting spatial and temporal distributions of the Barents Sea cod fishery

Climate change is expected to influence spatial and temporal distributions of fish stocks. The aim of this paper is to compare climate change impact on a fishery with other factors impacting the performance of fishing fleets. The fishery in question is the Northeast Arctic cod fishery, a well-documented fishery where data on spatial and temporal distributions are available. A cellular automata model is developed for the purpose of mimicking possible distributional patterns and different management alternatives are studied under varying assumptions on the fleets’ fishing aptitude. Fisheries management and fishing aptitude, also including technological development and local knowledge, turn out to have the greatest impact on the spatial distribution of the fishing effort, when comparing the IPCC’s SRES A1B scenario with repeated sequences of the current environmental situation over a period of 45 years. In both cases, the highest profits in the simulation period of 45 years are obtained at low exploitation levels and moderate fishing aptitude.     

Antarctic krill fishery effects over penguin populations under adverse climate conditions: Implications for the management of fishing practices

Fast climate changes in the western Antarctic Peninsula are reducing krill density, which along with increased fishing activities in recent decades, may have had synergistic effects on penguin populations. We tested that assumption by crossing data on fishing activities and Southern Annular Mode (an indicator of climate change in Antarctica) with penguin population data. Increases in fishing catch during the non-breeding period were likely to result in impacts on both chinstrap (Pygoscelis antarcticus) and gentoo (P. papua) populations. Catches and climate change together elevated the probability of negative population growth rates: very high fishing catch on years with warm winters and low sea ice (associated with negative Southern Annular Mode values) implied a decrease in population size in the following year. The current management of krill fishery in the Southern Ocean takes into account an arbitrary and fixed catch limit that does not reflect the variability of the krill population under effects of climate change, therefore affecting penguin populations when the environmental conditions were not favorable.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01386-w) contains supplementary material, which is available to authorized users.     

Depletion of coastal predatory fish sub-stocks coincided with the largest sea urchin grazing event observed in the NE Atlantic

In this contribution, we propose fishery driven predator release as the cause for the largest grazing event ever observed in the NE Atlantic. Based on the evolving appreciation of limits to population connectivity, published and previously unpublished data, we discuss whether overfishing caused a grazer bloom of the sea urchin (Strongylocentrotus droebachiensis) resulting in overgrazing of more than 2000 km² kelp (Laminaria hyperborea) forest along Norwegian and Russian coasts during the 1970 s. We show that coastal fisheries likely depleted predatory coastal fish stocks through modernization of fishing methods and fleet. These fish were important predators on urchins and the reduction coincided with the urchin bloom. From this circumstantial evidence, we hypothesize that coastal predatory fish were important in regulating sea urchins, and that a local population dynamics perspective is necessary in management of coastal ecosystems.     

Management Implications of the Response of Two Tilapiine Cichlids to Long-Term Changes in Lake Level,Allodiversity and Exploitation in an Equatorial Lake

The tilapiine cichlids Oreochromis leucostictus and Tilapia zillii were introduced into Lake Naivasha, Kenya, in 1956. Previous studies on data collected to 1987 revealed they were persistent following establishment, despite environmental variability and exploitation. Recent data, however, suggest this persistence is under threat as data indicate some significant declines in aspects of their abundance since 1999. The influence of changes in lake level, allodiversity and fishing effort on this decline was tested and showed that a decline in lake level was a significant causal factor. The recent change in allodiversity, with the establishment and dominance of Cyprinus carpio in the fishery, was not significant on the catch per unit effort of O. leucostictus but was on T. zillii. Since 1999, catches of tilapiines in the fishery have been independent of fishing effort, contrary to between 1975 and 1987, suggesting their management through application of fishery models may no longer be applicable. As it was anthropogenic-mediated lake level changes that were mainly responsible for their decline, then lake management should focus on sustainable water utilization that maximizes lake levels in accordance with the basin-wide water balance.     

A case study of human migration and the sea cucumber crisis in the Galapagos Islands

The sea cucumber fishing crisis in Galapagos is an example of the potential consequences of rapid migration, growing economic competition, and weak regulatory mechanisms. In a short period of time sea cucumber fishing has become the most inflammatory issue in the Galapagos. The key factors that allowed for the efficient exploitation of the new resource were not the fishermen themselves but rather the new fishing techniques and access to credit and markets. This suggests that the annual sea cucumber crisis is due to factors more complex than simply more fishermen generating greater sea cucumber catches. This paper examines census data and fisher registries to analyze population growth in the islands. A public opinion survey is used to determine the population's attitudes toward sea cucumber fishing and regulations. Qualitative interviews explore the history of the sea cucumber boom. Information from the sea cucumber monitoring program provides estimates for the annual sea cucumber catches.     

Using Vessel Monitoring System Data to Improve Systematic Conservation Planning of a Multiple-Use Marine Protected Area,the Kosterhavet National Park (Sweden)

When spatial fishing data is fed into systematic conservation planning processes the cost to a fishery could be ensured to be minimal in the zoning of marine protected areas. We used vessel monitoring system (VMS) data to map the distribution of prawn trawling and calculate fishing intensity for 1-ha grid cells, in the Kosterhavet National Park (Sweden). We then used the software Marxan to generate cost-efficient reserve networks that represented every biotope in the Park. We asked what were the potential gains and losses in terms of fishing effort and species conservation of different planning scenarios. Given a conservation target of 10 % representation of each biotope, the fishery need not lose more than 20 % of its fishing grounds to give way to cost-efficient conservation of benthic diversity. No additional reserved area was needed to achieve conservation targets while minimizing fishing costs. We discuss the benefits of using VMS data for conservation planning.     

Rehabilitating mussel beds in Coffee Bay,South Africa: Towards fostering cooperative small-scale fisheries governance and enabling community upliftment

Along the coast of South Africa, marine resources play a significant role in supporting livelihoods and contributing to food security in impoverished rural communities. Post-apartheid fisheries laws and policies have begun to address traditional fishing rights and development needs, and new management arrangements are being implemented. One such initiative has been the Mussel Rehabilitation Project in Coffee Bay, which piloted a resource rehabilitation technique at several over-exploited fishing sites. Mussel stocks in these exploited areas had dropped to under 1 % mussel cover, and during the project period, stocks increased to >80 % cover, supporting a sustainable harvest well above national daily bag limits. This stock enhancement was achieved only after the project had started to address social challenges such as the lack of local management institutions and the need to enhance food security. The project embarked on training and institution-building; it formed a robust community mussel management committee; and developed a local resource management plan, facilitating increased community participation in the day-to-day management of the resource. The project also saw the initiation of various ancillary projects aimed at improving food security and stimulating the local economy and hence alleviating pressure on the marine resources. Here we review this 10-year project’s outcomes, and present lessons for small-scale fisheries governance in South Africa and internationally. We show, through empirical experience, that balancing stock rebuilding needs in a context of widespread poverty and dependency on natural resources by a local fisher community can only be addressed through an integrated approach to development. Participation of resource users and a thorough understanding of the local context are imperative to negotiating appropriate small-scale fisheries governance approaches. We recommend that the implementation of South Africa’s newly minted Small-Scale Fisheries Policy should begin with bottom-up, demonstrative resource management measures such as mussel rehabilitation. This type of initiative can deliver short-term food security benefits and foster social learning towards sustainable and cooperative fisheries governance.     

Studying common-pool resources over time: A longitudinal case study of the Buen Hombre fishery in the Dominican Republic

Like many small-scale fishing communities around the world, the community of Buen Hombre in the Dominican Republic is dealing with a set of challenges to reconcile its fishing activities with the ecology on which it depends. Also like many such communities, this case has been examined at a particular period in time by a group of social scientists, but not over substantial lengths of time in order to examine the longitudinal validity of the conclusions made during this period. In this paper we combine data from previous anthropological work with our own primary social and ecological data to conduct a longitudinal case study of the Buen Hombre fishery. Our over-time comparison focuses on a suite of mostly social and institutional variables to explain what we find to be a continued degradation of the fishery, and we conclude the analysis by presenting a causal-loop diagram, summarizing our inferences regarding the complex interactions among these variables. We find that a mix of factors, notably changes in gear and fishing sites used, the number of fishermen and their livelihood diversity, as well as an increased connectivity between Buen Hombre and its external environment, have contributed to the decline of the condition of Buen Hombre coral reef fishery. We conclude with a discussion of what may lie ahead for this particular case and others like it.     

Present and past dynamics of Inughuit resource spaces

Information from a collaborative GPS tracking project, Piniariarneq, involving 17 occupational hunters from Qaanaaq and Savissivik, Northwest Greenland, is used to explore the resource spaces of hunters in Avanersuaq today. By comparison with historical records from the time of the Thule Trading Station and the decades following its closure, we reveal a marked variability in resource spaces over time. It is argued that the dynamics of resources and resource spaces in Thule are not underlain by animal distribution and migration patterns, or changes in weather and sea ice conditions alone; but also by economic opportunities, human mobility, settlement patterns, particular historical events and trajectories, and not least by economic and political interests developed outside the region.     

Migration,markets, and mangrove resource use on Kosrae,Federated States of Micronesia

Kosrae, Federated States of Micronesia, is a prototype of an island economy prone to economic crowding. Average family size is large, the habitable land area is small, economic activity is limited, and household dependence on natural resources for fuel and food is high. We analyze how economic crowding--and its mitigation through trade and migration policies--affects mangrove resource use. A comparison of household survey data from 1996 and 2000 indicates that despite decreases in US aid and public-sector jobs, average household consumption of mangrove resources has not increased. Migration and remittances have allowed the purchase of imported fuel and building materials substituting for mangrove wood. Despite changing preferences and shifts toward import consumption, population growth and further declines in US financial support will likely cause aggregate demand for mangrove and upland wood to rise. Moreover, continued emigration may accelerate the export of mangrove crabs to off-island Kosraeans.     

The Links Between Resource Dependency and Attitude of Commercial Fishers to Coral Reef Conservation in the Red Sea

The imperative to further constrain extractive uses of natural resources will strengthen as resources degrade through over-use or exposure to climate changes. Here, we explore an approach to increase the support for marine conservation among coral reef fishers. We explore the proposition that resource dependency in the Egyptian Red Sea can act as a barrier to conservation. We administered face-to-face surveys to 49% of the fishing industry to: (i) identify the level of compliance to the local marine protected area (MPA), (ii) assess the level of dependency on marine resources in the region and (iii) examine the relationship between resource dependency and conservation attitudes. Only 11.4% of fishers were aware of the MPA. Fishers were mostly limited in their social flexibility and livelihood options. Results suggest that resource dependency is highly and negatively correlated with conservation attitudes suggesting that management efforts need to seriously focus on reducing dependency if conservation goals are to be met.     

The Sulu-Sulawesi Sea: environmental and socioeconomic status, future prognosis and ameliorative policy options

The Sulu-Sulawesi Sea, with neighboring Indonesian Seas and South China Sea, lies at the center of the world's tropical marine biodiversity. Encircled by 3 populous, developing nations, the Philippines, Indonesia and Malaysia, the Sea and its adjacent coastal and terrestrial ecosystems, supports ca. 33 million people, most with subsistence livelihoods heavily reliant on its renewable natural resources. These resources are being impacted severely by rapid population growth (> 2% yr-1, with expected doubling by 2035) and widespread poverty, coupled with increasing international market demand and rapid technological changes, compounded by inefficiencies in governance and a lack of awareness and/or acceptance of some laws among local populations, particularly in parts of the Philippines and Indonesia. These key root causes all contribute to illegal practices and corruption, and are resulting in severe resource depletion and degradation of water catchments, river, lacustrine, estuarine, coastal, and marine ecosystems. The Sulu-Sulawesi Sea forms a major geopolitical focus, with porous borders, transmigration, separatist movements, piracy, and illegal fishing all contributing to environmental degradation, human suffering and political instability, and inhibiting strong trilateral support for interventions. This review analyzes these multifarious environmental and socioeconomic impacts and their root causes, provides a future prognosis of status by 2020, and recommends policy options aimed at amelioration through sustainable management and development.     

Extrapolating phosphorus production to estimate resource reserves

Various indicators of resource scarcity and methods for extrapolating resource availability are examined for phosphorus. These include resource lifetime, and trends in resource price, ore grade and discovery rates, and Hubbert curve extrapolation. Several of these indicate increasing scarcity of phosphate resources. Calculated resource lifetime is subject to a number of caveats such as unanticipated future changes in resource discovery, mining and beneficiation technology, population growth or per-capita demand. Thus it should be used only as a rough planning index or as a relative indicator of potential scarcity. This paper examines the uncertainty in one method for estimating available resources from historical production data. The confidence intervals for the parameters and predictions of the Hubbert curves are computed as they relate to the amount of information available. These show that Hubbert-type extrapolations are not robust for predicting the ultimately recoverable reserves or year of peak production of phosphate rock. Previous successes of the Hubbert curve are for cases in which there exist alternative resources, which is not the situation for phosphate. It is suggested that data other than historical production, such as population growth, identified resources and economic factors, should be included in making such forecasts.     

Distal impacts of aquarium trade: Exploring the emerging sandhopper (<Emphasis Type="Italic">Orchestoidea tuberculata</Emphasis>) artisanal shore gathering fishery in Chile

Artisanal fishery activities support the livelihoods of millions of people worldwide, particularly in developing countries. Within these fisheries, distal global drivers can promote switching between alternative target resources. These drivers can promote the rapid development of new, unregulated and previously unexploited fisheries that pose a threat to the sustainability of ecosystems. In this paper, we describe a new artisanal shore gathering activity that targets a previously unexploited resource: the sandhopper (Orchestoidea tuberculata). The activity is driven by aquarium trade demand for food. We used mixed methods to describe the activity, assessed basic socio-economic incentives, and estimated Catches per Unit Effort. Results show that the sandhopper plays an important role for the livelihoods of shore gatherers engaged in the activity. Gatherers have adapted and developed two main extraction methods with different degrees of investment and extraction rates. Furthermore, gatherers have developed local knowledge regarding the ecology and management of the resource. Results show that economic incentives can motivate a rapid expansion of this unregulated activity. Future research gaps and management options to address the development of this fishery are discussed in light of these findings.     

Large-scale environmental degradation results in inequitable impacts to already impoverished communities: A case study from the floating villages of Cambodia

Cambodian subsistence communities within the Tonle Sap Great Lake area rely on resource extraction from the lake to meet livelihood needs. These fishing communities—many of which consist of dwellings floating on the lake—face potentially profound livelihood challenges because of climate change and changing hydrology due to dam construction for hydroelectricity within the Mekong Basin. We conducted interviews across five village communities, with local subsistence fisher people in the Tonle Sap in 2015, and used thematic analysis methods to reveal a fishery system that is undergoing rapid ecological decline, with local fishing communities increasingly experiencing reductions in available fish stocks. As a result, over 100 000 people living in these communities are experiencing a direct loss of well-being and livelihood. We discuss these losses and consider their implications for the future viability of Cambodian floating village communities.     

Effects of the 1998 coral morality event on Kenyan coral reefs and fisheries

Data were collected in southern Kenya on coral reef ecosystems and fisheries to assess the influence of the 1998 coral bleaching and mortality event. We compared benthic cover, sea urchin and fish abundance in unfished marine parks and fished reefs and the reef-associated fisheries 3 years before and after 1998. Hard and soft coral decreased while coralline algae increased in both management areas. Turf increased in marine parks and sponge and fleshy algae increased in the fished reefs. Sea urchin grazer biomass was unchanged over this period and the fish community changed less than benthic cover. In general, butterflyfish, damselfish and wrasses were negatively influenced while surgeonfish and a few uncommon families were positively influenced by the substratum change. There was a 17% increase in fishing effort as measured by fishermen per day at each landing site and the total demersal catch declined by 8% and the catch per man declined by 21% after 1998. The decline in the total catch and CPUE combined with the increase in effort suggest an overexploited fishery and this makes it difficult to distinguish changes caused by coral mortality or fishing effort. The price of fish increased over this period and this caused an 18% increase in the total value of the fishery but no difference in the net income of individual fishermen.     

Assessment of Blue Mussel <Emphasis Type="Italic">Mytilus edulis</Emphasis> Fisheries and Waterbird Shellfish-predator Management in the Danish Wadden Sea

We assessed the blue mussel Mytilus edulis fishery management scheme introduced in 1994 in the Danish Wadden Sea that regulate fishing vessels, fishery quota, set-aside for mussel-eating birds and established zones closed to mussel fishery. The results showed (i) a reduction in the blue mussel biomass and mussel bed areas in zones closed to fishery, (ii) decrease in eiders Somateria mollissima numbers and increase or stable numbers for oystercatcher Haematopus ostralegus and herring gull Larus argentatus and (iii) that energy estimations based on ecological food requirements for the mussel-eating birds should be at least three times larger, than the amount set-aside in the mussel management scheme. It is concluded that the mussel management scheme had been unable to stabilize or increase the blue mussel stocks and to secure stable or increasing numbers for all target bird species. Thus, it is recommended to revise the present blue mussel management scheme in the Danish Wadden Sea, to continue and improve mussel stock and bird surveys, and to consider novel studies of the mussel-eating birds’ energetics for improved set-aside estimates and future assessments.