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Fisheries: Conservation and Management
Published in Yeqiao Wang, Coastal and Marine Environments, 2020
The single-species convention for stock assessment and fishery management developed during the industrialization of fishing technology and widespread depletion of fishery resources in the 20th century. Although overfishing persists in many fisheries, the implementation of management strategies to end overfishing has effectively reduced fishing mortality to within-sustainable limits in many regions and rebuilt many depleted stocks. The successes of single-species management strategies have reduced the effect of fishing on many populations and increased the influence of abiotic factors (e.g., climate change)[34] and biological interactions (e.g., predation and competition) with other species, prompting a transition to multispecies and ecosystem models. Ecological approaches to fisheries science and management involve the incremental inclusion of abiotic or biotic factors in single-species population dynamics models[35] or the holistic modeling of energy through aquatic ecosystems.[36] The integration of ecosystem components as well as the consideration of all human uses of aquatic systems promoted the development of integrated ecosystem assessments.[37] Ecosystem approaches to management require confrontation of many trade-offs for multiple ecosystem utilities.[38] Although environmental variability is considered in many fishery stock assessments and management plans, the effects of climate change have been observed in many fisheries through shifting geographic distributions, phenological changes, or trends in productivity, and these changes pose a challenge for stock assessment and estimating MSY.[39]
Ocean Biological Deserts
Published in Ajai, Rimjhim Bhatnagar, Desertification and Land Degradation, 2022
Overfishing refers to the fact of harvesting too many fish than nature can sustainably yield annually (Pauly et al. 2005). For instance, in the Mediterranean Sea, it is estimated that over 90% of stocks are overexploited (Colloca et al. 2017). Overfishing has had lasting effects on marine ecosystems and continues to be one of the greatest threats to ocean health (Pauly et al. 2005, Jackson et al. 2007, Halpern et al. 2015). Overfishing has resulted in habitat loss (Daskalov et al. 2007, Halpern et al. 2015). Habitat loss is not only detrimental to marine life but also affects other aspects of ocean health, such as coastal protection and carbon storage. The direct effects include reduction in fish biomass and decline in biodiversity and its composition (Cheung et al. 2009, Sunday et al. 2017), leading to the formation of ocean biological deserts. Subsequently, this will affect marine ecosystem goods and services (Halpern et al. 2012, Sumaila et al. 2019). Thus, overfishing turns a stable and efficient ecosystem into a stressed one. It reduces the abundance of high-value predators and also alters habitats by destroying and disturbing bottom topography and the associated habitats (e.g. seagrass and algal beds, coral reefs) and benthic communities. In addition to this, the use of harmful fishing gear (Chuenpagdee et al. 2003) negatively impacts the ocean habitats too. Some fishing techniques are destructive, such as using dynamite or cyanides or trawling in the wrong habitat. Fish processing plants are a source of marine pollution and release ozone-depleting aerosols. Poorly managed large-scale mariculture can damage coastal wetlands and nearshore ecosystems. Also, according to the FAO, there are currently 4.6 million fishing vessels in the oceans (FAO, 2018). This means more contributions towards GHG emissions.
Marine spatial planning
Published in David R. Green, Jeffrey L. Payne, Marine and Coastal Resource Management, 2017
Anne-Michelle Slater, Georgina Reid
Fish stocks are an excellent example of why the EBA is required. Overfishing can lead to the reduction or even extinction of certain species of fish. Using EBA, the amount of fish which can be taken to ensure the level of fish stocks is replenished, is therefore, considered above the desire of fisherman to maintain or increase the number of their catch to make a living.
Monitoring water color anomaly of lakes based on an integrated method using Landsat-8 OLI images
Published in International Journal of Digital Earth, 2022
Xiaoqin Yang, Ruqing Tong, Li Ma, Jian Li, Siqi Wang, Liqiao Tian
Lake Changhu (Figure 1(a)), the third-largest freshwater lake in Hubei Province, is located in the northeast suburbs of Jingzhou City (30°22′–30°33′ N, 112°12′–112°31′ E). It is a momentous wetland in the middle reach of the Yangtze River, surrounded by dikes and canals. The basin area of Lake Changhu is approximately 140 km2 with functions of fish breeding, flood control and storage, and domestic water supply. Due to reclamation, overfishing, seine farming and pollution, the lake is in a eutrophic state and the biodiversity of different trophic groups of organisms shows a strong degradation. Changes in diversity, dominant population and community structure of aquatic plants have led to simplification and dysfunction in the lake ecosystem, which has changed from a grassy lake to an algal lake (Guo et al. 2019).
Bringing back ecological flows: migratory fish, hydropower and legal maladaptivity in the governance of Finnish rivers
Published in Water International, 2019
Niko Soininen, Antti Belinskij, Anssi Vainikka, Hannu Huuskonen
In a broader context, populations of wild migratory salmonids are affected by numerous anthropogenic factors. For example, the major global threats to wild Atlantic salmon include (in addition to dam construction and stocking of hatchery-reared smolts) overfishing, river engineering, pollution and salmon aquaculture. Forseth et al. (2017) identified escaped farmed salmon and salmon lice (Lepeophtheirus salmonis) from fish farms as emerging population threats in Norway, and Gyrodactylus salaris parasite, freshwater acidification, hydropower regulation and other habitat alterations as stabilized threats. The threats vary regionally, and in the Baltic Sea basin, the management of stocking and sea ranching has been classified as the most urgent concern (Palmé et al., 2012).
Polyclonal antibody-based immunoassay of vitellogenin in Van fish (Alburnus tarichi)
Published in International Journal of Environmental Health Research, 2021
Elif Kaval Oğuz, Kerem Özdemir, Güler Ünal, Ahmet R. Oğuz
Van fish is a species listed in the IUCN Red List of threatened species, owing to a decrease in its population since the 1990s. The reason for this decrease is believed to be the pressure of extensive hunting on the population. This has led the Ministry of Agriculture, Food and Livestock of Turkey to extend the duration of prohibition of hunting during the breeding period. The decrease in the population is explained only in terms of overfishing, and the continuous increase in pollution in the lake is mostly ignored. Pollution can affect the fish at molecular and cellular levels as well as at the population level.