Fisheries and Fisheries Management

Granger-causality analysis of integrated-model outputs, a tool to assess external drivers in fishery

Rincón M, Corti R, Elvarsson B, Ramos F, Ruiz J. Granger-causality analysis of integrated-model outputs, a tool to assess external drivers in fishery. [Internet]. 2019 . Available from: https://marxiv.org/zn63y/
Freely available?: 
Yes
Summary available?: 
No
Type: Manuscript

Integrated models are able to combine several sources of data into a single analysis using joint likelihood functions, fostering the consistency of assumptions among analyses and the ability to diagnose goodness of fit and model-misspecification. Owing to their capacity to consistently combine diverse information, integrated models could detect the variability induced by external drivers, such as various environmental drivers, on key components of the stock dynamics (e.g. recruitment) in cases where these external drivers are relevant but not yet identified or incorporated into the modelling exercise. This diagnosing power could then be used to explore causality between fishery dynamics, as estimated by the integrated model, and external drivers. To achieve this aim, a correlation analysis is neither necessary nor sufficient to prove causation. An alternative statistical concept, Granger-causality, provides a framework that uses predictability, rather than correlation, to give more evidence of causation between time-series variables.

A two-step procedure to investigate external forcings in stock dynamics is proposed. First, an integrated model is implemented to detect anomalies that cannot be explained by the internal dynamics of the stock. Then, in a second step, Granger-causality is used to detect the external origin of these anomalies. This two-step procedure is explored using the European anchovy in the Gulf of Cádiz as an example population where the external (environmental) drivers are well documented. The fishery dynamics is first estimated through an age-length model (Gadget). Then Granger-causality is used to assess the predictive power of different environmental drivers on recruitment. The results indicate that this is a powerful procedure, although also with important limitations, to determine predictability and that it can be implemented in a wide variety of stocks and external drivers. Moreover, once Granger-causality has been identified, it is shown that it can be used to forecast by making few modifications of the integrated model used for diagnosis.

Mechanisms for science to shape US living marine resource conservation policy

Merrick R. Mechanisms for science to shape US living marine resource conservation policy. ICES Journal of Marine Science [Internet]. 2017 ;75(7):2319 - 2324. Available from: https://academic.oup.com/icesjms/article/75/7/2319/4748808
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

National Oceanic and Atmospheric Administration Fisheries are responsible for the stewardship of the US living marine resources and their habitat and for providing productive and sustainable fisheries, safe sources of seafood, the recovery and conservation of protected resources, and healthy ecosystems to the nation. Their approach to conservation requires, by legislative mandates, that management be informed by science. It has evolved into a four-step approach to providing this advice: (i) the national framework for conservation science, (ii) region specific implementation, (iii) development of unbiased, scientific advice as required by the framework, and (iv) scientists acting, as appropriate, as advocates and science communicators. This approach has been a conservation success where, e.g. 92% of known managed fish stocks are no longer being overfished and 84% of known stocks are at healthy levels, with the latter including 43 stocks rebuilt from depleted levels. In a changing marine climate, it is all the more important that marine conservation decisions be driven by science.

Comparative valuation of fisheries in Asian Large Marine Ecosystems with emphasis on the East China Sea and South China Sea LMEs

U. Sumaila R. Comparative valuation of fisheries in Asian Large Marine Ecosystems with emphasis on the East China Sea and South China Sea LMEs. Deep Sea Research Part II: Topical Studies in Oceanography [Internet]. In Press . Available from: https://www.sciencedirect.com/science/article/pii/S0967064518301504
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $39.95
Type: Journal Article

Asia’s marine waters are divided into 13 Large Marine Ecosystems (LMEs), which together generate about 50% of the global marine fish catch of ~110 million tonnes annually. Here, I carry out a comparative analysis and valuation of these 13 LMEs with a focus on fish values even though marine ecosystem valuation is much broader than the valuation of fisheries. The following indicators were employed: Catch level, landed values, and subsidy intensity. These are key indicators of a fishery because (i) catch is an indicator of the amount of fish available in weight for food security purposes; (ii) landed value is the firsthand value from which wages, profits and economic impact originate; and (iii) fisheries subsidy is a policy instrument, which if used wrongly can lead to overcapacity and overfishing. In the second part of this contribution, I use the East and South China Sea LMEs to further illustrate the value of ocean fisheries and some of the threats they face. To carry out the comparative analysis, I extracted data from the Sea Around Us and Fisheries Economics Research Unit databases at the University of British Columbia. I also rely on the data and analysis of the OceanAsia project supported by the ADM Capital Foundation Ltd of Hong Kong. The analysis suggests that Asian LMEs are crucial in terms of food security, economic and social benefits to tens of millions of people in Asia and around the world; are under strong overfishing pressure; and that action is needed through effective management to stem the overfishing tide in order to ensure that these LMEs continue to sustain the delivery of goods and services through time.

A Review of Habitat Connectivity Research for Pacific Salmon in Marine, Estuary, and Freshwater Environments

Flitcroft RL, Arismendi I, Santelmann MV. A Review of Habitat Connectivity Research for Pacific Salmon in Marine, Estuary, and Freshwater Environments. JAWRA Journal of the American Water Resources Association [Internet]. 2018 . Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/1752-1688.12708
Freely available?: 
No
Summary available?: 
No
Type: Journal Article

Long‐term conservation planning for diadromous fishes would benefit from a better understanding of both the role of connectivity among environments and habitat variability in the expression of life‐history diversity. Most of the scientific knowledge on habitat fragmentation and connectivity has been developed in terrestrial systems in the discipline of landscape ecology. Research on habitat connectivity in aquatic systems (e.g., salmonid research that spans the spectrum of habitats from freshwater to the sea) is uncommon and largely focused on barriers to fish passage. Here, we present a review of the literature characterizing current research patterns on habitat connectivity within and among environments for Pacific salmon. We found this topic is still incipient: the literature is dominated by studies of freshwaters, with few articles focusing on habitat needs in estuary and marine systems. Pan‐environment studies are rare, pointing to a gap in our understanding of complex habitat relationships that might be significant in the development of long‐term conservation and restoration plans for Pacific salmon, particularly in light of the potential impact of climate change.

Examining public support for international agreements on tuna management and conservation

Wakamatsu M, Managi S. Examining public support for international agreements on tuna management and conservation. Marine Policy [Internet]. In Press . Available from: https://www.sciencedirect.com/science/article/pii/S0308597X18300976
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $35.95
Type: Journal Article

Many tuna stocks are being depleted, and the bluefin tuna stock is of particular concern because it has been designated endangered or severely overexploited. Japan's actions are pivotal in protecting bluefin tuna stocks because high volumes are caught for sushi/sashimi. However, the efforts of the Japanese government to conserve these valuable stocks have been limited or even counterproductive, as the government currently seems to prioritise the short-term interests of the domestic fishing industry. In this study, public preferences are revealed, potentially affecting the position of the Japanese government in the long run by quantifying the extent to which public support could be generated with changes in specific features of the international agreement on the conservation and management of tuna resources. With a choice experiment that focused on the catch limits, target species, and parties who would be responsible for the expenses of monitoring, this paper finds that a fishery closure is the scenario least likely to inspire public support for tuna conservation. Japanese consumers favour a prompt management response to the overfishing of tuna fisheries beginning immediately when the exploitation of the stocks reaches an unsustainable level. Atlantic/Pacific bluefin tuna, compared to other tuna species, is a top conservation priority for Japanese consumers. These results indicate that although the current movement towards conserving bluefin tuna is publicly supported, conservation actions should have been initiated sufficiently early to avoid a drastic catch reduction before the stock was overfished or the population became endangered.

Transformations of Social-Ecological Systems - Co-creation, Co-evolution and Co-management of Japanese Coastal Fisheries: A Tool-box Approach

Makino M, Tajima H. Transformations of Social-Ecological Systems - Co-creation, Co-evolution and Co-management of Japanese Coastal Fisheries: A Tool-box Approach. In: Sato T, Chabay I, Helgeson J Singapore: Springer Singapore; 2018. pp. 309 - 331. Available from: https://link.springer.com/chapter/10.1007/978-981-13-2327-0_17
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $29.95
Type: Book Chapter

Taking changes, uncertainty and diversification of ecosystems and societies as prerequisites, the effective way to implement stable fisheries management involves engaging the stakeholders (e.g., fishers, authorities and researchers) in discussions of issues. Such dialogues allow the participants to select and implement initiatives for measures that suit the location in question. This process also can accommodate revisions to compensate for changes in nature and society as the results and significance of the initiatives are continually appraised via the varied knowledge possessed by the stakeholders. And, to support this kind of deliberation and decision-making, in cooperation with fishers, we have developed and are sharing a fisheries management tool-box. As a result, we are now able to compare various sites using a common framework, which enables us to search out general theories for fisheries management in the future. Moreover, by using the tool-box in recurring discussions among the diverse range of knowledge holders at the site in question, the diverse perspectives of stakeholders (including researchers) change. In turn, that change can be fed back to the tool-box, with the hope that it will contribute to “co-evolution” of knowledge related to fisheries management.

Young-of-the-year recruitment does not predict the abundance of older age classes in black rockfish in Barkley Sound, British Columbia, Canada

Haggarty DR, Lotterhos KE, Shurin JB. Young-of-the-year recruitment does not predict the abundance of older age classes in black rockfish in Barkley Sound, British Columbia, Canada. Marine Ecology Progress Series [Internet]. 2017 ;574:113 - 126. Available from: https://www.int-res.com/abstracts/meps/v574/p113-126/
Freely available?: 
Yes
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $5263.91
Type: Journal Article

Recruitment and connectivity are important criteria for designing effective marine protected areas, as coastal fish populations must be sustained by settling juveniles. However, patterns of recruitment are difficult to observe, and adults and juveniles may occupy distinct habitats. We examined patterns of adult black rockfish Sebastes melanops abundance with respect to habitat and spatiotemporal variability in recruitment of young-of-the-year (YOY) to determine how these variables influence population density in and around a rockfish conservation area (RCA). For most year classes, there was no relationship between the density of YOY and the density of 1 yr olds or the density of adults, and instead habitat variables such as topological complexity and the amount of rocky substrate predicted adult black rockfish abundance. For 1 year class of moderate abundance at the YOY stage but high abundance at the 1 yr old stage, a significant relationship between 1 yr olds and subsequent adults was observed. We surmise that overwinter survival of YOY fish may be an important determinant for year-class strength in black rockfish. Although a companion study found low recruitment of YOY inside the RCA, our data indicate that the density of many species of rockfish was higher inside the RCA. These results highlight how the density of adults can be determined by post-recruitment processes such as movement into suitable habitat and mortality, rather than by recruitment of YOY, and have implications for the design of marine reserve networks.

Persisting Worldwide Seabird-Fishery Competition Despite Seabird Community Decline

Grémillet D, Ponchon A, Paleczny M, Palomares M-LD, Karpouzi V, Pauly D. Persisting Worldwide Seabird-Fishery Competition Despite Seabird Community Decline. Current Biology [Internet]. In Press . Available from: https://www.sciencedirect.com/science/article/pii/S0960982218314180
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $31.50
Type: Journal Article

Fisheries transform marine ecosystems and compete with predators, but temporal trends in seabird-fishery competition had never been assessed on a worldwide scale. Using catch reconstructions for all fisheries targeting taxa that are also seabird prey, we demonstrated that average annual fishery catch increased from 59 to 65 million metric tons between 1970–1989 and 1990–2010. For the same periods, we estimated that global annual seabird food consumption decreased from 70 to 57 million metric tons. Despite this decrease, we found sustained global seabird-fishery food competition between 1970–1989 and 1990–2010. Enhanced competition was identified in 48% of all areas, notably the Southern Ocean, Asian shelves, Mediterranean Sea, Norwegian Sea, and Californian coast. Fisheries generate severe constraints for seabird populations on a worldwide scale, and those need to be addressed urgently. Indeed, seabirds are the most threatened bird group, with a 70% community-level population decline across 1950–2010.

A GIS-based framework for addressing conflicting objectives in the context of an ecosystem approach to fisheries management—a case study of the Portuguese sardine fishery

Szalaj D, Wise L, Rodríguez-Climent S, Angélico MM, Marques V, Chaves C, Silva A, Cabral H. A GIS-based framework for addressing conflicting objectives in the context of an ecosystem approach to fisheries management—a case study of the Portuguese sardine fishery. ICES Journal of Marine Science [Internet]. 2018 ;75(6):2070 - 2087. Available from: https://academic.oup.com/icesjms/article-abstract/75/6/2070/5062949?redirectedFrom=fulltext
Freely available?: 
No
Summary available?: 
No
Approximate cost to purchase or rent this item from the publisher: 
US $44.00
Type: Journal Article

An ecosystem approach to fisheries management (EAFM) is as a new paradigm in fisheries management. In this study, a combination of geographic information systems (GISs) and multi-criteria decision-making method (MCDM) is proposed as a framework supporting an ecosystem approach to European sardine (Sardina pilchardus, Clupeidae) fishery management in Portugal. This case study was chosen due to the recent severe decline shown by the species. To develop an EAFM for the sardine fishery, a set of criteria were defined based on literature review and expert knowledge. To address multiple conflicting objectives, namely conservation and fisheries, five scenarios were considered: (i) baseline; (ii) nurseries protection; (iii) spawning areas protection; (iv) fishery profit driven, and (v) safeguarding dependent fishing communities. Combination of GIS and MCDM methods highlighted important areas to implement spatial conservation measures for sardine. The analyses indicate that some areas are suitable for conservation in several scenarios, such as the area near Aveiro and the area near the Tejo estuary. However, conservation measures implemented in the area near Aveiro would imply higher economic trade-offs when compared with the actions applied in the region near the Tejo estuary. Results also suggested some of the conservation objectives, such as the protection of sardine eggs and juveniles, to not be compatible. The proposed framework is an important tool supporting EAFM by addressing conflicting objectives, trade-offs and identifying areas that could be considered as potential fishery closure sites or subjected to further analyses.

Ensemble habitat suitability modeling of vulnerable marine ecosystem indicator taxa to inform deep-sea fisheries management in the South Pacific Ocean

Georgian SE, Anderson OF, Rowden AA. Ensemble habitat suitability modeling of vulnerable marine ecosystem indicator taxa to inform deep-sea fisheries management in the South Pacific Ocean. Fisheries Research [Internet]. 2019 ;211:256 - 274. Available from: https://www.sciencedirect.com/science/article/pii/S0165783618303321
Freely available?: 
Yes
Summary available?: 
No
Type: Journal Article

Resolutions of the United Nations General Assembly (UNGA) require states and competent authorities to protect vulnerable marine ecosystems (VMEs), ecologically important habitats in the deep sea that are considered to be especially at risk from anthropogenic disturbances such as fishing. The lack of data concerning the location and extent of VMEs poses a significant obstacle to their protection. Habitat suitability modeling is increasingly used in spatial management planning due to its ability to predict the distribution and niche of marine organisms based on limited input data. We generated broad-scale, medium-resolution (1 km2) ensemble models for ten VME indicator taxa within the New Zealand Exclusive Economic Zone and a portion of the South Pacific Regional Fishery Management Organisation (SPRFMO) convention area. Ensemble models were constructed using a weighted average of three habitat suitability model types: Boosted Regression Trees, Maximum Entropy, and Random Forest. All models performed well, with area under the curve scores above 0.9, and ensemble models marginally outperformed any of the individual modeling approaches. Highly suitable habitat for each VME indicator taxa was predicted to occur in relatively small areas throughout the region, typically associated with elevated seafloor features with steep slopes. Determining the spatial distribution of VME indicator taxa is critical for assessing the current and historical extent of bottom trawling impacts on benthic communities, and for supporting the improved spatial management of fisheries in the South Pacific Ocean. Given the additional threats of climate change and ocean acidification to VME indicator taxa throughout the deep sea, habitat suitability modeling is likely to play an increasing role in designing effective, long-term protection measures for cumulative impacts on VMEs.

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