fish stock Articles
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Are fisheries going from bad to worse? The case of the Northeast Arctic cod
The Northeast Arctic cod is one of the few fish stocks with a long time series of landings, stock size, recruitment and rate of exploitation. This paper discusses how this stock and the catches it supports have developed since 1900. Both catches and the stock increased from 1900 until after the Second World War. After the war the stock declined and so did the catches from the late 1950s. A rising ...
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Recovering from overexploitation: the European fisheries of the North Sea
In the last two decades, the fisheries of the North Sea have experienced substantial declines in the population of a number of commercially harvested species. The fisheries have also experienced the development of considerable overcapacity as a result of ineffective management and subsidies. Management of the fishery is complicated by the existence not only of multiple species and gears, but also ...
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Individual Rationality and the “Zonal Attachment” Principle: Three Stock Migration Models
Shared fish stocks migrate across borders between different countries’ exclusive economic zones. This paper discusses the individual rationality of fish-sharing agreements based on the zonal attachment of such stocks. Three types of migrations are considered: (i) a common stock that grows and reproduces and is then distributed in given proportions between two countries’ zones at the beginning of ...
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Alternative futures for Southern Bluefin Tuna
This paper examines the outcomes of alternative management scenarios for the Southern Bluefin Tuna (SBT) fishery over the next 30 years. Two criteria are used to characterise outcomes: economic efficiency as measured by the present value of net benefits generated and conservation as measured by the predicted size of the spawning stock biomass in 20 years' time (SSB20). A bioeconomic model, ...
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Aquatic environment and yield of sea bass (Lates calcarifer, Bloch) in ponds
This study was conducted for three years to investigate the aquatic parameters and growth of sea bass at varying stocking densities and sizes and requirement of quantity of forage fish for its culture in ponds. Two separate experiments were conducted: one for determining growth and seed stocking density and the other for ascertaining of quantity of forage fish. Under experiment 1, two trials ...
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Fisheries management in a sea of uncertainty: the role and responsibility of scientists in attaining a precautionary approach
On the political level, there is now an agreement that the fish stocks in the North Sea should be managed in accordance with the precautionary principle. The goal of this paper is to show that fisheries scientists will have to adapt to the new requirements represented by this principle, first and foremost by adjusting the model of decision-making in a way that facilitates communication of the ...
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Challenges and opportunities for fisheries managers in developing countries: a case for economic eclecticism
Fisheries managers and advisors in developing countries face challenges that may be difficult to overcome, because they use doctrines, principles and models of management and economics that do not adequately explain the problems that need to be solved. This may perpetuate non-sustainable policies, because broader issues important to fisheries sustainability are not accounted for more eclectic ...
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Communities, knowledge and fisheries of the future
The 'human dimension' in fisheries management has historically been incorporated via a specific economic understanding of fisheries wedded to a single-species approach. Meeting the challenge of fisheries, however, will require a broadening of fisheries science towards an ecosystems-based approach. There is also the need for a parallel shift in social science understandings of fishing towards ...
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Stocking Tilapia / Aquaculture
Overview: To get a good crop of marketable fish it’s necessary to stock the pond with the correct number of fingerlings. Stocking too few fish may result in fast growth and large fish but this isn’t an economical use of the pond. However, stocking too many fish will result in slow growth and a large number of very small fish. Tilapia For all-male (monosex) culture of tilapia for ...
By Fishward
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Population dynamics of 15 fish species in Grand-Lahou lagoon (West Africa, Côte d’Ivoire)
This study described growth, mortality, recruitment patterns and exploitation rates of 15 fish species in Grand-Lahou lagoon (Côte d’Ivoire). Monthly length-frequency data collected from artisanal fisheries from November 2013 to October 2014 were analyzed with FiSAT software using the ELEFAN package to estimate the population parameters of fishes. Asymptotic values for total length ...
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The Ecological Fishprint of Nations: Measuring Humanity’s Impact on Marine Ecosystems
In November, 2006, a prominent team of ecologists and economists issued this dire warning: if current fishing patterns continue, all major commercial fish species will suffer population collapses by 2048. In March 2005, the United Nations State of the World Fisheries and Aquaculture report stated that 7 of the top 10 marine fish species, accounting for about 30 percent of all capture fisheries ...
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Continuous Data Delivers Added Protection for Singapore Fish Farmers
Overview Continuous water quality monitoring in the Strait of Johor supports an early warning system that helps fish farmers in Singapore protect their aquaculture operations from harmful algal blooms. Challenge Aquaculture has become an industry of special interest in Singapore. Yet, much of the country’s farmed fish comes from coastal operations vulnerable to sudden and dramatic ...
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Migration barriers protect indigenous brown trout (Salmo trutta) populations from introgression with stocked hatchery fish
Brown trout populations in the Belgian rivers Scheldt and Meuse have been intensively stocked in the past decades, often with material of uncertain origin. Moreover, the species habitat has become increasingly fragmented, preventing gene flow between neighboring populations. We assessed how this impacted genetic diversity and population structure by analyzing 12 wild populations (total n=309) and ...
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Use of sea water and hydraulic conditions. Potential cause of Mortality by Metals and Hydrogen Sulfide in Recirculation Fisheries
The traditional conception in Chile of the toxic effect of metals on cultured fish tends to weigh heavily on incoming freshwater in open flow fish farms as the major responsible for mortality in early stages of development in salmon species. This approach is mainly based on two conditions that refer to freshwater quality in Chile, and to the dilutive effect of recirculation fish stocks when a ...
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Pacific fisheries need tech to track climate impact
Climate change could benefit some Pacific fisheries, but tracking the success of adaptation needs effective monitoring, says Johann Bell. Climate change could derail plans by Pacific Island countries and territories (PICTs) to use fisheries and aquaculture to foster economic development and food security. Bottom-dwelling coastal fish are expected to be hardest hit. Under continued high ...
By SciDev.Net
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Feeding habits of the juvenile striped weakfish, Cynoscion guatucupa Cuvier 1830, in Bahía Blanca estuary (Argentina): seasonal and ontogenetic changes
The aim of this study was to analyze the feeding habits of the juvenile striped weakfish, Cynoscion guatucupa Cuvier, from Bahía Blanca estuary, Argentina. C. guatucupa is one of the most important regional fishing resources although in the last 10 years landings have greatly decreased. The year class strength of fish as well as stock size and yield are determined during the early life stages. ...
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Modeling fish production for Southern California's petroleum platforms
California's oil platforms are nearing the end of their productive lives, and therefore will be decommissioned in the near future. These structures have been shown to be important habitat for both settlement and growth for reef fishes. Important information on the biological effects (i.e. loss of biomass and production) of different decommissioning options has not yet been explored in detail. ...
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Chile Mandates Real-time Environmental Monitoring at Salmon Farms
Ocean-based fish farms in Chile have been ordered by Chilean officials to start monitoring environmental conditions in and around their pens in real time and immediately transmit the data to government environmental agencies. According to the August regulation from the Superintendencia de Medioambiente (SMA), ocean-based aquaculture sites will need to monitor water conditions for dissolved ...
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Modern strains put Lake Victoria in critical condition
Pollution and overfishing in Lake Victoria have become so severe that scientists believe they threaten the health and livelihoods of millions of East Africans. And researchers in the three countries bordering the world’s largest tropical lake — Kenya, Tanzania and Uganda — largely blame governments and national agencies for failing to control the effluent and other waste ...
By SciDev.Net
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How To Start A Catfish Farming In Nigeria
Catfish farming in Nigeria is the cultivation of one or more finned fish primarily for commercial purposes. In this article, you will learn how to start your own successful catfish farming business in Nigeria. We will provide you with all catfish farming tips so you can start your own catfish farming for profit. In terms of aquaculture, catfish farming is the most profitable in Nigeria. By the ...
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