Menakhem Ben-Yami EXECUTIVE SUMMARY The adequacy of the science and the consequent management prevailing in the Western World fisheries and its validity for the developing countries' fisheries is questioned. Population dynamics supported... more
Menakhem Ben-Yami
EXECUTIVE SUMMARY
The adequacy of the science and the consequent management prevailing in the Western World fisheries and its validity for the developing countries' fisheries is questioned. Population dynamics supported by mathematical/statistical models, and acoustic surveys, along with mainly single-species stocks assessment are inherently dependent on good real-time field data. But, even where available, those are the misleading equilibrium assumptions that have become the official science and basis for fisheries management, which considers fishing the almost sole cause for stock size fluctuations. Such management only too often doesn't pay sufficient attention to the human factor, in spite that humans are the only thing it can manage, and disregards most if not all environmental, abiotic and biotic factors that do affect fluctuations in fish populations. Generations of western fisheries scientists have been trained within this paradigm to which they stick for mental and institutional inertia.
For over a century, scientists independent of institutional pressure and inertia, realizing real-world fisheries ecology were publishing scientific reports, papers and even books trying to set the course straight, but so far with little success. Thus, most fishery-management scientists are spending most of their time in operating and discussing computer models, while trying to circumvent insufficient information and data flaws by manipulating the models with mathematical/statistical exercises. Unfortunately, this practice comes at the expense of on-board research, sampling and data collection and analysis, and keeps the scientists away from fishermen and their knowledge. With fisheries being a dynamic process where fish, fishermen, and ever-changing environment interact, no wonder that the western fisheries management is deficient. In addition, the canonical assumptions, such as: that the larger is the spawning stock the larger the recruitment; that single-species catch management is the remedy; that models can be valid without input of environmental factors, as well as the wisdom of selective fishing – are here questioned.
EXECUTIVE SUMMARY
The adequacy of the science and the consequent management prevailing in the Western World fisheries and its validity for the developing countries' fisheries is questioned. Population dynamics supported by mathematical/statistical models, and acoustic surveys, along with mainly single-species stocks assessment are inherently dependent on good real-time field data. But, even where available, those are the misleading equilibrium assumptions that have become the official science and basis for fisheries management, which considers fishing the almost sole cause for stock size fluctuations. Such management only too often doesn't pay sufficient attention to the human factor, in spite that humans are the only thing it can manage, and disregards most if not all environmental, abiotic and biotic factors that do affect fluctuations in fish populations. Generations of western fisheries scientists have been trained within this paradigm to which they stick for mental and institutional inertia.
For over a century, scientists independent of institutional pressure and inertia, realizing real-world fisheries ecology were publishing scientific reports, papers and even books trying to set the course straight, but so far with little success. Thus, most fishery-management scientists are spending most of their time in operating and discussing computer models, while trying to circumvent insufficient information and data flaws by manipulating the models with mathematical/statistical exercises. Unfortunately, this practice comes at the expense of on-board research, sampling and data collection and analysis, and keeps the scientists away from fishermen and their knowledge. With fisheries being a dynamic process where fish, fishermen, and ever-changing environment interact, no wonder that the western fisheries management is deficient. In addition, the canonical assumptions, such as: that the larger is the spawning stock the larger the recruitment; that single-species catch management is the remedy; that models can be valid without input of environmental factors, as well as the wisdom of selective fishing – are here questioned.
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Research Interests: Fisheries and Aquaculture
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The role of reactive oxygen species (ROS) in the killing of the bacterial pathogen Aeromonas salmonicida by in vitro cultured rainbow trout (Oncorhynchus mykiss) head kidney macrophages has been investigated. Using a microtitre plate... more
The role of reactive oxygen species (ROS) in the killing of the bacterial pathogen Aeromonas salmonicida by in vitro cultured rainbow trout (Oncorhynchus mykiss) head kidney macrophages has been investigated. Using a microtitre plate bactericidal assay the respiratory burst pathway responsible for ROS generation was inhibited completely using the NADPH oxidase inhibitor trifluoperazine and partially by the use of ROS scavengers (formate and/or mannitol) and the antioxidative enzymes SOD and/or catalase. Increased bacterial survival of an avirulent strain (MT004) in the presence of trifluoperazine, catalase and formate confirmed that ROS such as hydrogen peroxide and hydroxyl radicals were indeed an important killing agent. This was further confirmed using sodium nitroprusside and aminotriazole, inhibitors of SOD and catalase respectively. The presence of aminotriazole caused a significantly increased bactericidal activity against a virulent strain (MT423) normally resistant to killing by cultured resident rainbow trout head kidney macrophages.
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This chapter examines the various aspects of tuna oceanography. There are several major functions that tuna oceanography studies can provide for those working to understand tuna fisheries and related tuna biology. One is to help... more
This chapter examines the various aspects of tuna oceanography. There are several major functions that tuna oceanography studies can provide for those working to understand tuna fisheries and related tuna biology. One is to help understand the variations of catch statistics from various fisheries operating within similar or adjacent regions on one or more species of tunas. Another is to help understand the general shifts in apparent population abundances over large and small areas in time. The two major reproduction and juvenile growout regions in the Atlantic for several tuna species are the Sargasso Sea, southward toward the equator, and south of the equator into the South Atlantic central gyre. The cold-tolerant southern bluefin tuna reproduces during the fourth quarter and early first quarter in a region of the deepest tropical Indian Ocean off northwestern Australia. Surface-oriented skipjack and yellowfin schools dominate oceanic island surface fisheries. In the upper ocean, where adequate oxygen levels are met, the tropical tunas coexist, but as oxygen levels decline, the smaller tunas' requirements act quickly to exclude them, while the lesser demands of older and larger tunas allow them to swim and explore the lower oxygen levels. The longtail and blackfin tuna are tropical neritic species with life histories more like that of skipjack and they are similarly limited in the adult size they can attain.
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ABSTRACT An energetics model (ENSIM) for the exploited yellowfin tuna, Thunnus albacares, population in the eastern Pacific Ocean is developed. Hydrodynamic,properties and respiration-swimming work theory are combined,to describe the... more
ABSTRACT An energetics model (ENSIM) for the exploited yellowfin tuna, Thunnus albacares, population in the eastern Pacific Ocean is developed. Hydrodynamic,properties and respiration-swimming work theory are combined,to describe the energy expenditure due to swimming,as a function oflength for tunas. Growth and maintenance,energetics are estimated and incorporated into a simplistic three process model. This model,is interfaced with a population,simulator,(TUNPj1)P) and,minimal,energy requirements,for the exploited yellowfin tuna population are derived for the simulated fishing years 1964-72. A theoretical unexploited population simulation is made, and the energy requirements by this population are compared,with primary productivity rates and minimum,micronekton,(forage) standing stock availability. No obvious food limitation is indicated for yellowfin tunas greater than 40 cm, particularly since the exploited population is at a level of, at most, 50% of the unexploited biomass,estimates. Population limitation processes are examined,and indications that the recruit ment,rates are independent,of exploited biomass,are discussed. The intent of studies of the population,dynamics
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Views about aquatic resource management are changing, particulaly now that resource yields from world fisheries have been shown to be not only unsustainable, but steadily declining under conventional management practice. There is ample... more
Views about aquatic resource management are changing, particulaly now that resource yields from world fisheries have been shown to be not only unsustainable, but steadily declining under conventional management practice. There is ample reason for re-examination, and more pragmatic definitions of what is meant by sustainability There have nearly always been clear, reasonable means for making appropriate decisions that would have safeguarded most of the ocean's living resources, hut in general greed and lack of societal will, as articulated it national governmental levels, have promoted the present resource deterioration. I also posit that the underlying science in support of sustainable fisheries decision-making has been responsible for a great proportion of this deterioration. Revitalization of fisheries science, indeed rehabilitating the affected fisheries, will he required to regain the losses in credibility of the agencies and of the underlying science. This will depend upon resumption of integrated environmental monitoring, more enlightened application of what is already known, and reconnection of the science to the several industries involved, i.e. fishing, processing and marketing. Management implemented at the market place may be one of the few remaining options to secure the sustainability of natural resources
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... reprint the quotations on page v from: THE LOG FROM THE SEA OF CORTEZ by John Steinbeck Copyright John Steinbeck and Edward F. Ricketts, 1941 Copyright John Steinbeck, 1951 By permission of Mcintosh and Otis, Inc. THE LOG FROM THE SEA... more
... reprint the quotations on page v from: THE LOG FROM THE SEA OF CORTEZ by John Steinbeck Copyright John Steinbeck and Edward F. Ricketts, 1941 Copyright John Steinbeck, 1951 By permission of Mcintosh and Otis, Inc. THE LOG FROM THE SEA OF CORTEZ by John ...