Decline Of Fisheries Research Articles

Can nature deliver on the sustainable development goals?

The increasing availability of data and improved analytical techniques now enable better understanding of where environmental conditions and human health are tightly linked, and where investing in nature can deliver net benefits for people—especially with respect to the most vulnerable populations in developing countries. These advances bring more opportunities for interventions that can advance multiple SDGs at once. We have harmonised a suite of global datasets to explore the essential nexus of forests, poverty, and human health, an overlap of SDG numbers 1, 2, 3, 6, and 15. Our study combined demographic and health surveys for 297 112 children in 35 developing countries with data describing the local environmental conditions for each child (appendix).4 This allowed us to estimate the effect forests might have in supporting human health, while controlling for the influence of important socio-economic differences.4 We extended this work to look at how forests affect three childhood health concerns of global significance for the world's poorest people: stunting, anaemia, and diarrhoeal disease.

Bonefish in South Florida: status, threats and research needs

Bonefish (Albula vulpes) support a world-renowned fishery in South Florida, USA. However, fishing guides and anglers have been reporting significant declines in bonefish angling quality over that past three decades. In the absence of any long-term bonefish stock and ecosystem assessments, the cause of this decline in the fishery is unclear. Here we summarize our current knowledge of bonefish ecology in Florida and discuss potential causes of fishery decline. Reductions and alterations in freshwater flows from the Everglades have caused major changes in bonefish habitat, including acute (anoxic conditions) and chronic (changes in benthic flora and fauna) effects in Florida Bay and Biscayne Bay. Various pollutants from agricultural and urban runoff may also be impacting bonefish population(s) directly and/or indirectly throughout their range. Efforts to locate juvenile A. vulpes in Florida have been largely unsuccessful to date, suggesting abundances may be low, and/or juveniles have unknown habitat requirements in Florida. Further, bonefish larvae may be sourced from adult individuals outside of Florida in areas such as Cuba or Mexico, in which case bonefish conservation in other regions is highly relevant to the Florida population. Extreme weather events may have also contributed to the decline; an extreme cold spell in 2010 caused significant bonefish mortality and coincided with documented declines in the fishery. The fishery may also be impacting the population. We outline research needs and potential approaches to better understand the causes of the bonefish decline in Florida and restore populations of this ecologically and socioeconomically important species.

The assessment of fishery status depends on fish habitats

AbstractAt the crux of the debate over the global sustainability of fisheries is what society must do to prevent over‐exploitation and aid recovery of fisheries that have historically been over‐exploited. The focus of debates has been on controlling fishing pressure, and assessments have not considered that stock production may be affected by changes in fish habitat. Fish habitats are being modified by climate change, built infrastructure, destructive fishing practices and pollution. We conceptualize how the classification of stock status can be biased by habitat change. Habitat loss and degradation can result in either overly optimistic or overly conservative assessment of stock status. The classification of stock status depends on how habitat affects fish demography and what reference points management uses to assess status. Nearly half of the 418 stocks in a global stock assessment database use seagrass, mangroves, coral reefs and macroalgae habitats that have well‐documented trends. There is also considerable circumstantial evidence that habitat change has contributed to over‐exploitation or enhanced production of data‐poor fisheries, like inland and subsistence fisheries. Globally many habitats are in decline, so the role of habitat should be considered when assessing the global status of fisheries. New methods and global databases of habitat trends and use of habitats by fishery species are required to properly attribute causes of decline in fisheries and are likely to raise the profile of habitat protection as an important complementary aim for fisheries management.

The decline of fisheries on the Madeira River, Brazil: The high cost of the hydroelectric dams in the Amazon Basin

AbstractDespite being considered beneficial by providing a clean and renewable source of energy, the construction of hydroelectric dams has extremely negative implications for Amazonian fisheries. This study investigated the impacts of the Santo Antônio and Jirau hydroelectric dams on the fishery stocks of the Madeira River. This investigation was based on fish catch data from the Z‐31 fishing colony, located in the municipality of Humaitá, in Amazonas State, Northern Brazil. Data were collected daily and provided information on the date of return from each trip, the fish species targeted, and the total catch (kg) between January 2002 and September 2017. The results indicated reductions of 39% in the mean annual catch and 34% in the mean monthly catches. These results highlight the high price paid by local fish communities for the development of hydroelectric power in the Amazon basin.

Celebrating the 25th International Conference of The International Environmetrics Society

Celebrating the 25th International Conference of The International Environmetrics Society

Contemporary and emerging fisheries in The Bahamas—Conservation and management challenges, achievements and future directions

AbstractThe harvest of marine resources has long‐standing cultural and economic importance to The Bahamas and other small island developing states. Tourists and residents place a demand on local marine resources, particularly Caribbean spiny lobster, Panulirus argus (Latreille), queen conch, Lobatus gigas (Linnaeus) and Nassau grouper, Epinephelus striatus (Bloch), and many fishery products are also sold on the global market. Illegal, unreported and unregulated fishing coupled with inadequate regulations and enforcement are the main factors contributing to the decline of Bahamian fisheries along with other anthropogenic impacts. This article reviews the status of fisheries management in The Bahamas using economically and ecologically important species as case studies to highlight conservation successes, knowledge gaps and deficiencies in existing management approaches. The review concludes with an examination of how emerging fisheries and improved conservation management strategies have the potential to improve economic and food security throughout the archipelago.

Widespread mosquito net fishing in the Barotse floodplain: Evidence from qualitative interviews.

BackgroundThe insecticide-treated mosquito net (ITN) is a crucial component of malaria control programs, and has prevented many malaria cases and deaths due to scale up. ITNs also serve effectively as fishing nets and various sources have reported use of ITNs for fishing. This article examines how widespread the practice of mosquito net fishing with ITNs is.MethodsWe conducted in-depth interviews with fishery personnel and traditional leadership from the Barotse Royal Establishment in Western Province, Zambia, to better understand the presence or absence of the use of ITNs as fishing nets. We then coded the interviews for themes through content analysis. Additionally we conducted a desk review of survey data to show trends in malaria indicators, nutritional status of the population and fish consumption.ResultsAll those interviewed reported that ITNs are regularly used for fishing in Western Zambia and the misuse is widespread. Concurrently those interviewed reported declines in fish catches both in terms of quantity and quality leading to threatened food security in the area. In addition to unsustainable fishing practices those interviewed referenced drought and population pressure as reasons for fishery decline. Malaria indicators do not show a trend in declining malaria transmission, fish consumption has dropped dramatically and nutritional status has not improved over time.ConclusionsDespite the misuse of the ITNs for fishing all those interviewed maintained that ITN distribution should continue. Donors, control programs and scientists should realize that misuse of ITNs as fishing nets is a current problem for malaria control and potentially for food security that needs to be addressed.

Reforming Provisional (2007-2008) <i>Sarotherodon galilaeus</i> Landing Decline in Lake Kinneret (Israel)

The background for the case analysis of the present paper is the landing decline of Sarotherodon galilaeus during 2007-2008 to the annual level of <10 ton whilst normal harvests varied between 170 and 350 t/y. The objectives of the study are aimed at exploring limnological conditions and fishery management which might be the cause for this case. The research methods are focusing at long-term analysis of entire environmental conditions. The results indicatively highlight that, as other fluctuations of limnological parameters (Plankton, Nutrients) in Lake Kinneret, the fishery decline of S. galilaeus is attributed to normal periodical cyclic trends. Therefore, a recommendation that was submitted as a total fishing ban for three years was strongly opposed. The total fishing ban recommendation was rejected because further demolishing processes within the ecosystem were predicted. This conclusion was justified later (2011-2016) when annual landings came to the normal level. Conclusive recommendations considered that the fishing ban was indicated as “Ecological Disorder” and its replacement by controlled fishing policy as “Order Policy” was successfully implemented.

Post-productivist transformation as a challenge for small-scale fisheries: Changing preconditions and adaptation strategies in the Finnish Archipelago Sea Region

This article focuses on changes in the use of fish resources and its interrelationships with societal and natural transformations in the Baltic Sea setting within the last 100 years. The study area, the Finnish Archipelago Sea Region, consists of unique coastal landscape with shallow water areas between thousands of islands and islets. Fishing income was traditionally combined with shipping and small-scale agriculture, but today fishing families’ income combinations are more diverse. The fishing livelihood in the archipelago is typically seasonal operation and targets several fish species with e.g. gill nets.Extraction of fish resources has been of utmost economic and cultural importance in the Archipelago Sea Region: fisheries contributed to habitation of outer parts of the region at the turn of the 20th century. In mid 20th century fishing started to lose its profitability and many islands became desolated. Decline in the fishing employment was due, for instance, to technical development, urbanization and industrialization of the society. In the 1970s a new innovation, fish farming in net cages, compensated for the decline of capture fisheries. At the same time the production landscape of fishing peasants began its change towards one of leisure and nature conservation. This post-productivist transformation contained not only an increase in the competition of space, but also a remarkable change in people’s perceptions and values about the use and governance of fish resources. This analysis is based on a wide collection of published articles, books and documents, together with unpublished interview material illuminating the most recent transformations.

Dynamic patterns of overexploitation in fisheries

Understanding overfishing and regulating fishing quotas is a major global challenge for the 21st Century both in terms of providing food for humankind and to preserve the oceans’ ecosystems. However, fishing is a complex economic activity, affected not just by overfishing but also by such factors as pollution, technology, financial factors and more. For this reason, it is often difficult to state with complete certainty that overfishing is the cause of the decline of a fishery. In this study, we developed a simple dynamic model specifically designed to isolate and to study the role of depletion on production. The model is based on the well-known Lotka-Volterra model, or Prey-Predator mechanism, assuming that the fish stock and the fishing industry are coupled variables that dynamically affect each other. In the model, the fishing industry acts as the “predator” and the fish stock as the “prey”. If the model can fit historical data, in particular relative to the productive decline of specific fisheries, then we have a strong indication that the decline of the fish stock is driving the decline of the fishery production. The model doesn’t pretend to be a general description of the fishing industry in all its varied forms; however, the data reported here show that the model can describe several historical cases of fisheries whose production decreased and collapsed, indicating that the overexploitation of the fish stocks is an important factor in the decline of fisheries.

The consistency of a species' response to press perturbations with high food web uncertainty.

Predicting species responses to perturbations is a fundamental challenge in ecology. Decision makers must often identify management perturbations that are the most likely to deliver a desirable management outcome despite incomplete information on the pattern and strength of food web links. Motivated by a current fishery decline in inland lakes of the Midwestern United States, we evaluate consistency of the responses of a target species (walleye [Sander vitreus]) to press perturbations. We represented food web uncertainty with 193 plausible topological models and applied four perturbations to each one. Frequently the direction of the focal predator response to the same perturbation is not consistent across food web topologies. Simultaneous application of management perturbations led to less consistent outcomes compared to the best single perturbation. However, direct manipulation of the adult focal predator produced a desirable outcome in 77% of 193 plausible topologies. Identifying perturbations that produce consistent outcomes in the face of food web uncertainty can have important implications for natural resource conservation and management efforts.

Sea change.

A policy-focused history probes the factors driving the decline of global fisheries

Of Sea Lice and Superfood: A Comparison of Regional and National News Media Coverage of Aquaculture

As wild fisheries decline, aquaculture, or the cultivation of species in fresh and salt water, will provide the majority of seafood consumed worldwide. Given that aquaculture is an increasingly critical food “technology” – with implications for public opinion formation – we apply theory of social function systems and sustainability to a U.S. news media content analysis. We examine coverage of aquaculture (N = 493 articles) over a ten-year period (2005-2015), comparing four regional and four national newspapers for discussion of risks, benefits, science, economics, political/legal issues, and environmental sustainability. Results suggest the dominance of risk in regional and national news; however, we also find more recent attention to benefit and sustainability. Differences within and between regional and national newspaper coverage further suggest that the conversation about aquaculture varies within the U.S., is multi-dimensional, and involves frequent co-occurrence

SOCIOECONOMIC AND LIVELIHOOD ANALYSIS OF HILSA FISHERS OF LOWER STRETCH OF GANGA

The present study was conducted to understand the socio-economic and livelihood features of the hilsa fishers in Hooghly-Bhagirathi river system and also to find out the reasons of decline in hilsa fishery as perceived by the fishers. Results of the analysis revealed that 60% of the hilsa fishers belonged to jele/malo community and the average experience in hilsa fishing was for about 20 years. Hilsa fishery contributed 38.84% in annual family income of fishers’ households. Lower hilsa catch in Hooghly-Bhagirathi river system during the past ten years led to large scale forced migration among the fishers’ community. The younger generation of fisherfolk had lost their interest from fishery particularly of hilsa fishery due to uncertain income. Six reasons behind decline of hilsa fishery as perceived by the fishers were documented and ranked. According to the fishers, ‘use of destructive fishing gears’ (mean score 66.06) was ranked as first among the reasons behind decline in hilsa fishery followed by ‘erratic rainfall’ (64.54); ‘huge catch of hilsa fish in lower part of Hooghly/sea mouth’ (60.3); ‘industrial pollution in Hooghly River’ (52.3) and ‘freshwater discharge/influx’ (35.07). Poor implementation of mesh size regulation, poor enforcement of closed season in rivers, ineffective extension services, and recurring climatic hazards made the hilsa fishery more vulnerable. The government, fishery cooperatives, NGOs and other related organisations need to join hands to support the hilsa fishers for sustainable hilsa fishery management.

Effects of environmental chemicals on fish thyroid function: Implications for fisheries and aquaculture in Australia

Numerous environmental stressors exert acute or chronic effects on the fish thyroid cascade. Such effects could be mediated via thyroidal alterations, imbalance of plasma T4 and T3 levels or damage to the structure of the thyroidal tissues (thyroid hypertrophy, hyperplasia). The thyroidal system is intricately linked to other endocrine systems in vertebrates including the control of reproduction. Disruption of fish thyroid function by environmental stressors has the potential to result in deleterious effects including the inhibition of sperm production, reduction in egg production, gonad development, ovarian growth, swimming activity, fertilisation and increase in larval mortality. Thyroid hormones play a major role in the development and growth of fish, particularly during their early life stages, thus, thyroid disruption by environmental stressors could inhibit the growth of fish larvae and juveniles in wild fish and cultured species, limit fish seed production and result in a decline in wild fisheries. This review highlights the effects of several environmental toxicants including PBDE, PCBs, PCDD and PCDF, PAH/oil, phthalates, metals, pesticides, mixed pollutants/chemicals, cyanide; and other stressors including acid (low pH) and ammonia, on fish thyroid function. Environmental sources of chemical stressors and appropriate water quality guidelines to protect the freshwater and marine species for the relevant pollutants are also discussed including (when available) the Australian guidelines (2000) and Canadian water quality guidelines (where Australian guidelines are not available). To date there has been no published research on the effects of anthropogenic environmental pollutants on the thyroid system of any native Australian fish species. However, the detection of high risk chemicals (notably PBDEs, PCBs, PAHs, metals and pesticides) in Australian waterways and Australian fish and shellfish implies that thyroid disruption of Australian wild fish and aquacultured species could occur. It is therefore imperative that the effects of such pollutants on the thyroid system of Australian native fish be investigated.

Subsistence in isolation: Fishing dependence and perceptions of change on Kiritimati, the world's largest atoll

Small island nations are reliant on local fishery resources due to their geographic isolation. The people of Kiritimati, the world's largest atoll, are ranked amongst the most vulnerable to degradation of their local reef resources because of their high reef dependence and exposure to threats. We conducted semi-structured interviews in 103 households, stratified across the atoll's five villages, to characterize Kiritimati's fishery, and to examine people's perceptions of the fishery status and their fishery dependence (assessed by responses to hypothetical declines in fishery catches). High immigration rates have created a shifting baseline in the community, with more recent immigrants perceiving the local fishery to be in better condition than those who have fished on Kiritimati over the long term. Due to their high dependence on fishery resources and limited alternatives for feeding their families, 70% of respondents anticipated continuing to fish even during a fifty percent hypothetical fishery decline. Despite these limitations to adaptive capacity, the people of Kiritimati were open to discussing new conservation policies that would conserve their fisheries, suggesting that locally supported conservation strategies may aid in alleviating some of their vulnerability. This study demonstrates how poverty and geographic isolation can drive low adaptive capacity to resource changes, and suggests that policy interventions are needed to avoid further reef fishery degradation and to support fishery-dependent livelihoods.

Litterfall Production of Mangroves in Huizache-Caimanero Lagoon System, México

ABSTRACT Flores-Cardenas, F.; Hurtado-Oliva, M.A.; Doyle, T.W.; Nieves-Soto, M.; Diaz-Castro, S., and Manzano-Sarabia, M., 2017. Litterfall production of mangroves in Huizache-Caimanero lagoon system, Mexico. The ecological legacy of the Huizache-Caimanero lagoon system has long been known as a trophically rich and productive ecosystem that supported artisanal fisheries of local and regional importance; however, a decline in fisheries' yields has been observed in recent decades. Mangroves are a fundamental component of this ecosystem, though data records and field studies are lacking in describing their structure and seasonal characteristics. Mangrove litterfall production was monitored during 2012–13 and described for the dominant species, Avicennia germinans (L.) Stearn and Laguncularia racemosa (L.) C.F. Gaertn. Forest surveys and monthly litter collections were obtained along a latitudinal gradient within the larger lagoon system to characterize the forest structure, leaf biomass, and related biologic...

Recovery of a Surf Clam Donax deltoides Population in Southern Australia: Successful Outcomes of Fishery‐Independent Surveys

AbstractEstimates of biomass or relative biomass are required for monitoring the recovery of depleted bivalve resources and for the management of newly exploited resources. Uncertainty around fishery catch per unit effort (CPUE) as a proxy for biomass highlights the need for fishery‐independent assessments. Following a prolonged period of decline in Australia's largest fishery for surf clam Donax deltoides, robust estimates of biomass were required to monitor recovery and to set appropriate total allowable commercial catches. Estimates of relative biomass were derived from fishery‐independent surveys (FIS) conducted cooperatively by researchers and fishers. The FIS assessed both the spatial (m to km) and temporal (months to years) dynamics of the fishery and enabled comparisons with CPUE. Concurrent size‐frequency distributions provided information on the mechanisms underlying variability in resource status across the fishery. Increasing relative biomass and complexity of size structures indicated recovery of the resource from 2009, although spatial contraction of the resource also occurred. Relative biomass from FIS provides a robust fishery performance indicator that is appropriate to the scale of the fishery and has advantages over fishery‐dependent CPUE of finer temporal and spatial resolution and consistent sampling efficiency. Performance indicators based on FIS provide improved understanding of the changes in resource status. Active engagement of fishers contributes to enhanced economic and environmental outcomes.Received December 9, 2014; accepted September 3, 2015

Status of fisheries in Egypt: reflections on past trends and management challenges

This paper provides a summary from primary and grey literature on the current status of fisheries in Egypt. It also discusses gaps which may impede effective management, and highlights future challenges. Total national seafood production has grown steadily overall in the last 15 years due to the rapid growth of aquaculture, despite a decline in fisheries production (about 23 %) from 1997 to 2012. The total production in 2012 was approximately 1,371,975 tonnes, tripling the 457,036 tonnes obtained in 1997. Fisheries production amounted to 354,237 tonnes (25 %) whilst aquaculture produced 1,017,738 (75 %) tonnes in 2012. Fisheries in Egypt’s northern lakes were the most important (36 %) followed by marine fisheries in the Mediterranean and Red Seas (32 %), which had the greatest variations in catch. The main decline in wild fisheries was due to the reduced landings from both marine and northern lake fisheries. Egypt has a wide variety of marine and freshwater species, comprising Sardina pilchardus, Penaeus japonicus, Mugil cephalus, and Saurida undosquamis, etc.; while Oreochromis niloticus, Clarias gariepinus are the main cultured species. The Egyptian fishing fleet increased by over 40 % from 3415 motorised vessels in 1997–4909 vessels in 2012. Most of these (3046 vessels, 62 %) fish in the Mediterranean, while the rest (1863 vessels, 38 %) fish in the Red Sea. Longlines were the fishing gear most used by the motorised vessels (45 %), followed by trawlers (26 %). Policy during the past few decades has been development-oriented, encouraging investment in aquaculture to ensure sustainable fish production, rather than managing wild fisheries in a sustainable way. Despite vigorous efforts through national legislation to address fishery management issues, the weak enforcement, low compliance and unregulated fishing suggest the need to restructure the fisheries management system. The main fisheries stakeholders (policy makers, scientists and fishery managers) should consider the different scales of these fisheries and the context in which they operate, in order to develop suitable management strategies.

High impact of low-trophic-position invaders: nonnative grazers alter the quality and quantity of basal food resources

AbstractLow-trophic-position animals, such as herbivorous and detritivorous fishes, mollusks, and crustaceans, have been introduced and become established in aquatic ecosystems throughout the globe. After introduction, they have the potential to change community structure and ecosystem processes fundamentally. Armored catfishes (Siluriformes:Loricariidae) are grazing fishes that have an extensive nonnative distribution. High population densities of nonnative loricariids have been linked to the decline of freshwater fisheries in invaded habitats, but the mechanisms underlying declines are poorly understood. We coupled the results of 2 loricariid exclosure experiments with a comparison of invaded and uninvaded sites to measure the effects of loricariids on the quantity and quality of food resources in a tropical stream. Loricariid grazing reduced the standing stock of benthic organic matter and algal biomass in experimental manipulations and in the site comparison. Moreover, grazing by loricariids significa...