Patrik Rönnbäck

The ecological basis for economic value of seafood production supported by mangrove ecosystems

The undervaluation of natural products and ecological services generated by mangrove ecosystems is a major driving force behind the conversion of this system into alternative uses. This trend of undervaluation is partly due to the difficulty involved in placing a monetary value on all relevant factors, but lack of ecological knowledge and a holistic approach among those performing the evaluation may be even more important determinants. This article identifies and synthesizes ecological and biophysical links of mangroves that sustain capture fisheries and aquaculture production. Fish, crustacean and mollusc species associated with mangroves are presented and the ecology of their direct use of this system is reviewed. Through a coastal seascape perspective, biophysical interactions among mangroves, seagrass beds and coral reefs are illustrated. The life-support functions of mangrove ecosystems also set the framework for sustainable aquaculture in these environments. Estimates of the annual market value of capture fisheries supported by mangroves ranges from US

Ecosystem perspectives on management of disease in shrimp pond farming

750 to 16 750 per hectare, which illustrates the potential support value of mangroves. The value of mangroves in seafood production would further increase by additional research on subsistence fisheries, biophysical support to other ecosystems, and the mechanisms which sustain aquaculture production.

Ecosystem services of the tropical seascape : interactions, substitutions and restoration

This paper reviews and discusses, from an ecological perspective, the causes behind the development and spreading of pathogens in shrimp aquaculture. The risk of disease in shrimp farming often inc ...

Ecological engineering in aquaculture: use of seaweeds for removing nutrients from intensive mariculture

The tropical coastal ‘‘seascape’’ often includes a patchwork of mangroves, seagrass beds, and coral reefs that produces a variety of natural resources and ecosystem services. By looking into a limi ...

Ecosystem goods and services from Swedish coastal habitats: identification, valuation, and implications of ecosystem shifts.

Rapid scale growth of intensive mariculture systems can often lead to adverse impacts on the environment. Intensive fish and shrimp farming, being defined as throughput-based systems, have a continuous or pulse release of nutrients that adds to coastal eutrophication. As an alternative treatment solution, seaweeds can be used to clean the dissolved part of this effluent. Two examples of successfully using seaweeds as biofilters in intensive mariculture systems are discussed in this paper. The first example shows that Gracilaria co-cultivated with salmon in a tank system reached production rates as high as 48.9 kg m−2 a−1, and could remove 50% of the dissolved ammonium released by the fish in winter, increasing to 90–95% in spring. In the second example, Gracilaria cultivated on ropes near a 22-t fish cage farm, had up to 40% higher growth rate (specific growth rate of 7% d−1) compared to controls. Extrapolation of the results showed that a 1 ha Gracilaria culture gave an annual harvest of 34 t (d. wt), and assimilated 6.5% of the released dissolved nitrogen. This production and assimilation was more than twice that of a Gracilaria monoculture. By integrating seaweeds with fish farming the nutrient assimilating capacity of an area increases. With increased carrying capacity it will be possible to increase salmon cage densities before risking negative environmental effects like eutrophication and toxic algal blooms sometimes associated with the release of dissolved nutrients. The potential for using mangroves and/or seaweeds as filters for wastes from intensive shrimp pond farming is also discussed. It is concluded that such techniques, based on ecological engineering, seems promising for mitigating environmental impacts from intensive mariculture; however, continued research on this type of solution is required.

The return of ecosystem goods and services in replanted mangrove forests: perspectives from local communities in Kenya

Abstract Coastal areas are exposed to a variety of threats due to high population densities and rapid economic development. How will this affect human welfare and our dependence on natures capacity to provide ecosystem goods and services? This paper is original in evaluating this concern for major habitats (macroalgae, seagrasses, blue mussel beds, and unvegetated soft bottoms) in a temperate coastal setting. More than 40 categories of goods and services are classified into provisional, regulating, and cultural services. A wide variety of Swedish examples is described for each category, including accounts of economic values and the relative importance of different habitats. For example, distinguishing characteristics would be the exceptional importance of blue mussels for mitigation of eutrophication, sandy soft bottoms for recreational uses, and seagrasses and macroalgae for fisheries production and control of wave and current energy. Net changes in the provision of goods and services are evaluated for three cases of observed coastal ecosystem shifts: i) seagrass beds into unvegetated substrate; ii) unvegetated shallow soft bottoms into filamentous algal mat dominance; and iii) macroalgae into mussel beds on hard substrate. The results are discussed in a management context including accounts of biodiversity, interconnectedness of ecosystems, and potential of economic valuation.

Regime Shifts and Ecosystem Service Generation in Swedish Coastal Soft Bottom Habitats: When Resilience is Undesirable

Mangroves are severely threatened ecosystems, with loss rates exceeding those of rainforests and coral reefs, stressing the need for large-scale rehabilitation programmes. Not only are ecological e ...

Seagrass Ecosystems in the Western Indian Ocean

Ecosystems can undergo regime shifts where they suddenly change from one state into another. This can have important implications for formulation of management strategies, if system characteristics develop that are undesirable from a human perspective, and that have a high resistance to restoration efforts. This paper identifies some of the ecological and economic consequences of increased abundance of filamentous algae on shallow soft bottoms along the Swedish west coast. It is suggested that a successive increase in the sediment nutrient pool has undermined the resilience of these shallow systems. After the regime shift has occurred, self-generation properties evolve keeping the system locked in a high-density algae state. The structural and functional characteristics of the new system state differ significantly from the original one, resulting in less valuable ecosystem goods and services generated for society. In Sweden, loss of value results from the reduced capacity for mitigating further coastal eutrophication, reduced habitat quality for commercial fishery species, and the loss of aesthetic and recreational values.

Aquaculture and Energy Use

Abstract Seagrasses are marine angiosperms widely distributed in both tropical and temperate coastal waters creating one of the most productive aquatic ecosystems on earth. In the Western Indian Ocean (WIO) region, with its 13 reported seagrass species, these ecosystems cover wide areas of near-shore soft bottoms through the 12 000 km coastline. Seagrass beds are found intertidally as well as subtidally, sometimes down to about 40 m, and do often occur in close connection to coral reefs and mangroves. Due to the high primary production and a complex habitat structure, seagrass beds support a variety of benthic, demersal and pelagic organisms. Many fish and shellfish species, including those of commercial interest, are attracted to seagrass habitats for foraging and shelter, especially during their juvenile life stages. Examples of abundant and widespread fish species associated to seagrass beds in the WIO belong to the families Apogonidae, Blenniidae, Centriscidae, Gerreidae, Gobiidae, Labridae, Lethrinidae Lutjanidae, Monacanthidae, Scaridae, Scorpaenidae, Siganidae, Syngnathidae and Teraponidae. Consequently, seagrass ecosystems in the WIO are valuable resources for fisheries at both local and regional scales. Still, seagrass research in the WIO is scarce compared to other regions and it is mainly focusing on botanic diversity and ecology. This article reviews the research status of seagrass beds in the WIO with particular emphasis on fish and fisheries. Most research on this topic has been conducted along the East African coast, i.e. in Kenya, Tanzania, Mozambique and eastern South Africa, while less research was carried out in Somalia and the Island States of the WIO (Seychelles, Comoros, Reunion (France), Mauritius and Madagascar). Published papers on seagrass fish ecology in the region are few and mainly descriptive. Hence, there is a need of more scientific knowledge in the form of describing patterns and processes through both field and experimental work. Quantitative seagrass fish community studies in the WIO such as the case study presented in this paper are negligible, but necessitated for the perspective of fisheries management. It is also highlighted that the pressure on seagrass beds in the region is increasing due to growing coastal populations and human disturbance from e.g. pollution, eutrophication, sedimentation, fishing activities and collection of invertebrates, and its effect are little understood. Thus, there is a demand for more research that will generate information useful for sustainable management of seagrass ecosystems in the WIO.

The "ecological footprint" : communicating human dependence on nature's work

aquaculture The farming of aquatic organisms, including fish, mollusks, crustaceans, and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, and protection from predators. Farming also implies individual or corporate ownership of the stock being cultivated. embodied energy density The accumulated energy use per area of production. Can include both direct and indirect industrial energy inputs as well as fixation of solar energy in ecological systems. emergy The sum of the available energy (exergy) of one kind previously required directly and indirectly through input pathways to make a product or service. energy intensity (EI) The accumulated energy inputs required to provide a given quantity of a product or service of interest. In the current context, energy intensity is expressed as the total joules of energy required to produce a live-weight tonne of fish, shellfish, or seaweed. fossil fuel equivalents An expression of auxiliary energy inputs from the economy, embodied in goods and services (e.g., 1 unit of electricity1⁄4 3–4 units of fossil fuels). industrial energy analysis (IEA) The sum of the energy (fossil fuel equivalents) needed for manufacturing machinery and products used as inputs to the system, and the fuel energy needed for operation. life-support systems The parts of the earth that provide the physiological necessities of life, namely, food and other energies, mineral nutrients, oxygen, carbon dioxide, and water; the functional term for the environment, organisms, processes, and resources interacting to provide these physical necessities. solar energy equivalents A unit making it possible to combine ecological and economic energy requirements, based on the energy from solar fixation. It takes about 10 times of solar fixation per 1 unit of fossil fuel.