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Resilient rivers and connected marine systems: a review of mutual sustainability opportunities
- Henry H. Hansen, Eva Bergman, Ian G. Cowx, Lovisa Lind, Valentina H. Pauna, Kathryn A. Willis
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- Journal:
- Global Sustainability / Volume 6 / 2023
- Published online by Cambridge University Press:
- 25 November 2022, e2
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Non-technical summary
Rivers are crucial to the water cycle, linking the landscape to the sea. Human activities, including effluent discharge, water use and fisheries, have transformed the resilience of many rivers around the globe. Sustainable development goal (SDG) 14 prioritizes addressing many of the same issues in marine ecosystems. This review illustrates how rivers contribute directly and indirectly to SDG 14 outcomes, and also provides ways to potentially address them through a river to sea view on policy, management and research.
Technical summaryThe United Nations initiated the SDGs to produce ‘a shared blueprint for peace and prosperity for people and the planet, now and into the future’. Established in 2015, progress of SDGs directed at the aquatic environment is slow despite an encroaching 2030 deadline. The modification of flow regimes combined with other anthropogenic pressures underpin ecological impacts across aquatic ecosystems. Current SDG 14 targets (life below water) do not incorporate the interrelationships of rivers and marine systems systematically, nor do they provide recommendations on how to improve existing management and policy in a comprehensive manner. Therefore, this review aims to illustrate the linkages between rivers and marine ecosystems concerning the SDG 14 targets and to illustrate land to sea-based strategies to reach sustainability goals. We provide an applied case study to show how opportunities can be explored. We review three major areas where mutual opportunities are present: (1) rivers contribute to marine and estuary ecosystem resilience (targets 14.1, 14.2, 14.3, 14.5); (2) resilient rivers are part of the global fisheries sustainability concerns (targets 14.4, 14.6, 14.7, 14.B) and (3) enhancing marine policy and research from a river and environmental flows perspective (targets 14.A, 14.C).
Social media summaryRestoring resilience to rivers and their environmental flows helps fulfil SDG 14.
17 - Maintaining taxonomic skills; the decline of taxonomy – a threat to fish conservation
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- By Maria J. Collares-Pereira, University of Lisbon, Paul H. Skelton, Rhodes University, Ian G. Cowx, University of Hull
- Edited by Gerard P. Closs, University of Otago, New Zealand, Martin Krkosek, University of Toronto, Julian D. Olden, University of Washington
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- Book:
- Conservation of Freshwater Fishes
- Published online:
- 05 December 2015
- Print publication:
- 03 December 2015, pp 535-562
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Summary
INTRODUCTION
Species, however defined, are the generally accepted unit of biology, including in conservation biology where it is more conventional to consider elements in terms of landscape units, ecosystems or communities (Mace, 2004). Here we consider how a general decline in systematics and taxonomy, the science dealing with the identification, description, naming and classifying of organisms, might affect fish conservation (Reid, 2010).
The link between species and conservation has many facets and implications, all of which have changed over time as the paradigms of both systems themselves have changed. The one constant that a ‘species’ has for conservation is that of linkage and communication, of being the instrument through which conservation issues are brought into a common understanding for different audiences. The iconic nature of certain species linked to conservation illustrates this point – giant pandas, rhinos, elephants, tigers, the blue whale or, more relevant to this chapter, species like golden trout, Atlantic salmon, sturgeon, Tennessee darter, coelacanth, Australian lungfish and Asian arowana – all have clear conservation connotations. In every case, the icon connects directly to an environment or ecosystem and threats to its existence, and critically to the human dimensions of its conservation needs. Were it not that fish and fisheries are of major economic and cultural importance (Welcomme et al., 2010), this situation might not be considered that serious, but fishes are key components of aquatic ecosystems and are both an essential food resource as well as a source of other products. They also play a major cultural role, from aesthetics to pets and leisure, in the lives of millions of people (Reid et al., 2013).
Their taxonomy is thus critical to recognise the threats to their existence and the steps required to conserve them. It is our contention, therefore, that conservation is all about ‘human’ concerns and actions, and, as such, taxonomy is a critical component in the process. A ‘taxonomic impediment’ (or insufficient taxonomic expertise) has been raised as a problem for understanding the extent of the biodiversity crisis that currently faces society. As represented in Figure 17.1, taxonomic capacity has been declining and conservation demand clearly increasing, particularly under obligations to international directives and conventions (e.g. Convention on Biological Diversity, Rio+20, the European Habitats and Water Framework Directives), and drives to protect landscapes and habitats.
15 - Sustainable inland fisheries – perspectives from the recreational, commercial and subsistence sectors from around the globe
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- By Steven J. Cooke, Carleton University, Vivian M. Nguyen, Carleton University, John M. Dettmers, Great Lakes Fishery Commission, Robert Arlinghaus, Humboldt University, Michael C. Quist, University of Idaho, Denis Tweddle, South African Institute of Aquatic Biodiversity, Olaf L. F. Weyl, South African Institute of Aquatic Biodiversity, Rajeev Raghavan, St. Albert's College, Marcela Portocarrero-Aya, Instituto de Investigación de Recursos Naturales Alexander von Humboldt, Edwin Agudelo Cordoba, Instituto Amazónico de Investigaciones Científi cas SINCHI, Ian G. Cowx, University of Hull
- Edited by Gerard P. Closs, University of Otago, New Zealand, Martin Krkosek, University of Toronto, Julian D. Olden, University of Washington
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- Book:
- Conservation of Freshwater Fishes
- Published online:
- 05 December 2015
- Print publication:
- 03 December 2015, pp 467-505
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Summary
INTRODUCTION
Globally, freshwater ecosystems provide varied fishing opportunities (herein termed inland fisheries) represented by three sectors: recreational, commercial and subsistence fisheries. From the depths of the Laurentian Great Lakes to the shallow floodplains of the Ganges River, and from under-ice fisheries in Scandinavia to the rice fields of Southeast Asia, fish and other aquatic life are omnipresent components of fluvial and lacustrine systems. Freshwater fishes generate many ecosystem services that extend beyond their use in fisheries (Holmlund & Hammer, 1999; Cowx & Portocarrereo, 2011). Given the diversity of freshwater fish assemblages, levels of fisheries productivity, cultural norms, density of human population and socioeconomic conditions, it is not surprising that there is immense variation in how, why and the extent to which freshwater fishes and other aquatic animals are exploited. Whether it be sustaining livelihoods through the provision of essential nutrients, generating income, or enabling leisure time with family, inland fisheries are important. Although there are accepted definitions for the three fishing sectors (i.e. UN FAO – see below), ambiguities and exceptions remain that complicate appraisal and management.
Compared with marine waters where industrial-scale commercial fisheries predominate, inland fisheries tend to be smaller in scale and catches generally do not enter the global marketplace. Moreover, whereas exploitation pressures are the primary threat facing marine fish populations and marine ecosystems, in inland systems there are multiple threats including many unrelated to fishing (Arlinghaus et al., 2002). Indeed, declines in freshwater fish fauna are implicated with broad-scale economic activities such as flow regulation, hydropower, agriculture, urbanisation and pollution (Limburg et al., 2011; Chapters 4 and 9). Reflecting the multiple threats, freshwater fishes are among the most imperilled taxa on the globe (Strayer & Dudgeon, 2010; Chapter 2), freshwater biodiversity is in crisis (Dudgeon et al., 2006) and freshwater ecosystems are among the most altered (Kennish, 2002; Malmqvist & Rundle, 2002). Despite the many threats to inland fishes and fisheries, they receive disproportionally less interest and attention from the global conservation community and international political spheres. Indeed, global capture statistics underrepresented inland fisheries and their contribution to global production (Welcomme et al., 2010; Welcomme, 2011a,b), partly because of the diffuse nature of inland fisheries (Beard et al., 2011). By contrast, it is comparatively easy to generate data for commercial fisheries where products sold on established domestic and export markets can be readily monitored.
Effect of dietary protein on the nitrogen excretion and growth of the African catfish, Clarias gariepinus
- Louise G. Buttle, Roger F. Uglow, Ian G. Cowx
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- Journal:
- Aquatic Living Resources / Volume 8 / Issue 4 / October 1995
- Published online by Cambridge University Press:
- 15 October 1995, pp. 407-414
- Print publication:
- October 1995
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The rates of growth and nitrogen efflux (total nitrogen and ammonia) of individual C. gariepinus ($\bar{x}~=~32.2$ g; S.D. = 4.8 g) kept under 4 feeding regimens, following a 48 h imposed fast (phase l), were measured periodically. In phase 2 (35 d), groups A, B and C were fed a 49.75%, 45.55% or 41.10% protein diet respectively at a ration of 0.5% body weight (1 d−1) Group D were not fed. In phase 3 (25 d) all groups were fed the 41.10% diet. In phase 1, the ammonia efflux rates were lower than any of the values found in either phase 2 and 3. In phase 2, group A (49.75%) had a higher mean ammonia efflux rates than the other groups and ammonia comprised 60-100% of the total nitrogen efflux in all groups. Group D showed a direct relationship between ammonia efflux rate and length of fast. In phase 3, refeeding with the 41.1% protein diet caused the ammonia efflux rates of groups B and D to converge within 7 days to values no different from those of group C, but group A maintained a significantly higher mean value until day 25. During phase 2, the growth rates in B (45.55%) were greatest, but, none of the among groups differences were significant. Group D fish (unfed) lost approximately 30% of their initial weight during phase 2. Nitrogen efflux rates, notably ammonia, showed a pattern of excretion that was directly related to the protein content of the diet, but that the source of dietary protein, dietary energy and the total available energy also influenced nitrogen metabolism. The small differences in growth found were related to between diet differences in composition. The weight loss in the unfed group of fish was probably attributable to the utilisation of lipid and/or protein reserves as metabolic fuels.