16 resultados para whaling

em DigitalCommons@University of Nebraska - Lincoln


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In an open letter published last year in the New York Times, 21 distinguished scientists (including three Nobel laureates) criticized Japan's program of scientific research whaling, noting its poor design and unjustified reliance upon lethal sampling. In a recent Forum article in BioScience, Aron, Burke, and Freeman (2002) castigate the letter's signers and accuse them of meddling in political issues without sufficient knowledge of the science involved in those issues.

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North Pacific right whales (Eubalaena japonica) were extensively exploited in the 19th century, and their recovery was further retarded (severely so in the eastern population) by illegal Soviet catches in the 20th century, primarily in the 1960s. Monthly plots of right whale sightings and catches from both the 19th and 20th centuries are provided, using data summarized by Scarff (1991, from the whale charts of Matthew Fontaine Maury) and Brownell et al. (2001), respectively. Right whales had an extensive offshore distribution in the 19th century, and were common in areas (such as the Gulf of Alaska and Sea of Japan) where few or no right whales occur today. Seasonal movements of right whales are apparent in the data, although to some extent these reflect survey and whaling effort. That said, these seasonal movements indicate a general northward migration in spring from lower latitudes, and major concentrations above 40°N in summer. Sightings diminished and occurred further south in autumn, and few animals were recorded anywhere in winter. These north-south migratory movements support the hypothesis of two largely discrete populations of right whales in the eastern and western North Pacific. Overall, these analyses confirm that the size and range of the right whale population is now considerably diminished in the North Pacific relative to the situation during the peak period of whaling for this species in the 19th century. For management purposes, new surveys are urgently required to establish the present distribution of this species; existing data suggest that the Bering Sea, the Gulf of Alaska, the Okhotsk Sea, the Kuril Islands and the coast of Kamchatka are the areas with the greatest likelihood of finding right whales today.

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Morishita’s “multiple analysis”of the whaling issue [Morishita J. Multiple analysis of the whaling issue: Understanding the dispute by a matrix. Marine Policy 2006;30:802–8] is essentially a restatement of the Government of Japan’s whaling policy, which confuses the issue through selective use of data, unsubstantiated facts, and the vilification of opposing perspectives. Here, we deconstruct the major problems with Morishita’s article and provide an alternative view of the whaling dispute. For many people in this debate, the issue is not that some whales are not abundant, but that the whaling industry cannot be trusted to regulate itself or to honestly assess the status of potentially exploitable populations. This suspicion has its origin in Japan’s poor use of science, its often implausible stock assessments, its insistence that culling is an appropriate way to manage marine mammal populations, and its relatively recent falsification of whaling and fisheries catch data combined with a refusal to accept true transparency in catch and market monitoring. Japanese policy on whaling cannot be viewed in isolation, but is part of a larger framework involving a perceived right to secure unlimited access to global marine resources. Whaling is inextricably tied to the international fisheries agreements on which Japan is strongly dependent; thus, concessions made at the IWC would have potentially serious ramifications in other fora.

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Eighteen years after initiating scientific whaling in Antarctic waters, Japan presented a new and more ambitious program to the International Whaling Commission (IWC); the proposal was made in early June during the IWC’s annual meeting in Ulsan, Korea. Japan now wishes to more than double its annual catch of Antarctic minke whales (from about 440 to 935), and to expand lethal sampling to include an additional yearly take of 50 humpback and 50 fin whales. Unlike catches for commercial whaling, scientific catches are unregulated. Since 1987, Japan has taken some 6,800 minke whales from Antarctic waters, despite ongoing criticism of the relevance and direction of Japan’s research. The IWC was set up to regulate commercial whaling and to conserve whale populations, under the authority of the 1946 International Convention for the Regulation of Whaling. Following a well-documented failure of management that led to the collapse of most global whale populations, the IWC set a zero quota for commercial whaling (the moratorium). This was made effective from 1986. Norway, the former Soviet Union and Japan initially objected to the moratorium, but Japan withdrew its objection and ceased commercial whaling in 1988.

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You published recently (Nature 374, 587; 1995) a report headed "Error re-opens 'scientific' whaling debate". The error in question, however, relates to commercial whaling, not to scientific whaling. Although Norway cites science as a basis for the way in which it sets its own quota. scientific whaling means something quite different. namely killing whales for research purposes. Any member of the International Whaling Commission (IWC) has the right to conduct a research catch under the International Convention for the Regulation of Whaling. 1946. The IWC has reviewed new research or scientific whaling programs for Japan and Norway since the IWC moratorium on commercial whaling began in 1986. In every case, the IWC advised Japan and Norway to reconsider the lethal aspects of their research programs. Last year, however, Norway started a commercial hunt in combination with its scientific catch, despite the IWC moratorium.

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Apparently alarmed that an advertisement in Nature referencing the study of Baker and Palumbi (Science 265, 1538; 1994) might lend undeserved credence to the notion that illegal whale products find their way into Japanese markets, Milton Freeman (Nature 376, 11; 1995) reiterates the arguments of the Fisheries Agency of Japan (FAJ) that the study is fundamentally flawed. As Freeman's letter contains several serious errors, we feel obliged to comment.

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Normile reports on Japan's expanded scientific whaling program and notes that "Canada, the United States, the Soviet Union, South Africa, and Japan were among several countries that [conducted scientific whaling] before 1982 [the year the IWC passed the worldwide commercial moratorium on whaling], but in recent years Japan has stood alone." Although true, this statement omits three equally important points.

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Selection of the appropriate management unit is critical to the conservation of animal populations. Defining such units depends upon knowledge of population structure and upon the timescale being considered. Here, we examine the trajectory of eleven subpopulations of five species of baleen whales to investigate temporal and spatial scales in management. These subpopulations were all extirpated by commercial whaling, and no recovery or repopulation has occurred since. In these cases, time elapsed since commercial extinction ranges from four decades to almost four centuries. We propose that these subpopulations did not recover either because cultural memory of the habitat has been lost, because widespread whaling among adjacent stocks eliminated these as sources for repopulation, and/or because segregation following exploitation produced the abandonment of certain areas. Spatial scales associated with the extirpated subpopulations are frequently smaller than those typically employed in management. Overall, the evidence indicates that: (1) the time frame for management should be at most decadal in scope (i.e., <100 yr) and based on both genetic and nongenetic evidence of population substructure, and (2) at least some stocks should be defined on a smaller spatial scale than they currently are.

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The most significant cetacean trade items until commercial whaling all but ceased in the 1990s (aside from scientific exchanges of tissues etc.) were meat and blubber from baleen whales for human consumption. Since then, live dolphins and 'small' whales for display (and to some extent for research, military use, and 'therapy') have become the most significant cetacean 'products' in international trade. Trade in live cetaceans is presently dominated by bottlenose dolphins (Tursiops spp.), beluga whales (Debhinapterns leucas) and to a lesser extent killer whales (Orcinus orca) (Fisher and Reeves 2005). In the past, most of the dolphins in trade were common bottlenose dolphins (Tursiops truncatus) originating in the United States, Mexico and the Black Sea, but since the 1980s the United States has essentially stopped its capture-for-export activities and in 2001Mexico implemented a moratorium on live-captures. The source countries for dolphins in trade are now geographically diverse, but Cuba and Japan are currently major source nations for common bottlenose dolphins. Russia is the only current source for belugas. Russia and Japan have become the main potential sources for killer whales since Iceland ceased exporting them in the 1980s or early 1990s.

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The great whales of the Southern Ocean were extensively exploited by modern whaling methods, with the first catches made in the Falkland Islands Dependencies region of IWC Management Area II in 1904 (Tønnesson and Johnsen, 1982; Hart, 2006). Exploitation went through several phases. Populations of humpback whales, Megaptera novaeangliae, and blue whales, Balaenoptera musculus, around South Georgia crashed around the time of World War I, and further exploitation occurred in other regions into the 1930’s. There was a hiatus in whaling during World War II, but large-scale catches resumed in Antarctic waters after 1945.

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Most species of baleen whales were subject to intensive overexploitation by commercial whaling in this and previous centuries, and many populations were reduced to small fractions of their original sizes. Here, we review the status of baleen whale stocks, with an emphasis on those that are known or thought to be critically endangered. Current data suggest that, of the various threats potentially affecting baleen whales, only entanglement in fishing gear and ship strikes may be significant at the population level, and then only in those populations which are already at critically low abundance. The impact of some problems (vessel harassment, and commercial or aboriginal whaling) is at present probably minor. For others (contaminants, habitat degradation, disease), existing data either indicate no immediate cause for concern, or are insufficient to permit an assessment. While the prospect for many baleen whales appears good, there are notable exceptions; populations that are of greatest concern are those suffering from low abundance and associated problems, including (in some cases) anthropogenic mortality. These include: all Northern Right Whales Eubalaena glacialis, Bowhead Whales Balaena mysticetus of the Okhotsk Sea and various eastern Arctic populations, western Gray Whales Eschrichtius robustus, and probably many Blue Whale Balaenoptera musculus populations. We review the status of these populations and, where known, the issues potentially affecting their recovery. Although Humpback Whales Megaptera novaeangliae and Southern Right Whales Eubalaena australis were also heavily exploited by whaling, existing data indicate strong recovery in most studied populations of these species.

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We review catches of humpback whales (Megaptera novaeangliae) in the Southern Ocean during the period following World War II, with an emphasis on Areas IV, V and VI (the principal regions of illegal Soviet whaling on this species). Where possible, we summarize legal and illegal Soviet catches by year, Area and factory fleet, and also include information on takes by other nations. Soviet humpback catches between 1947 and 1973 totaled 48702 and break down as follows: 649 (Area I), 1412 (Area II), 921 (Area III), 8779 (Area IV), 22569 (Area V) and 7195 (Area VI), with 7177 catches not assignable to area. In all, at least 72542 humpback whales were killed by all operations (Soviet plus other nations) after World War 2 in Areas IV (27201), V (38146) and VI (7195). More than a third of these (25474 whales, of which 25192 came from Areas V and VI) were taken in just two seasons, 1959/60 and 1960/61. The impact of these takes, and of those from Area IV in the late 1950's, is evident in the sometimes dramatic declines in catches at shore stations in Australia, New Zealand and Norfolk Island. When compared to recent estimates of abundance, the large removals from Areas IV and V indicate that the populations in these regions remain well below pre-exploitation levels despite reported strong growth rates off eastern and western Australia. Populations in many areas of Oceania continue to be small, indicating that the catches from Area VI and eastern Area V had long-term impacts on recovery.

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The seasonal distributions of humpback and blue whales (Megaptera novaeangliae and Balaenoptera musculus, respectively) in the North Atlantic Ocean are not fully understood. Although humpbacks have been studied intensively in nearshore or coastal feeding and breeding areas, their migratory movements between these areas have been largely inferred. Blue whales have only been studied intensively along the north shore of the Gulf of St. Lawrence, and their seasonal occurrence and movements elsewhere in the North Atlantic are poorly known. We investigated the historical seasonal distributions of these two species using sighting and catch data extracted from American 18th and 19th century whaling logbooks. These data suggest that humpback whales migrated seasonally from low-latitude calving/ breeding grounds over a protracted period, and that some of them traveled far offshore rather than following coastal routes. Also, at least some humpbacks apparently fed early in the summer west of the Mid-Atlantic Ridge, well south of their known present-day feeding grounds. In assessing the present status of the North Atlantic humpback population, it will be important to determine whether such offshore feeding does in fact occur. Blue whales were present across the southern half of the North Atlantic during the autumn and winter months, and farther north in spring and summer, but we had too few data points to support inferences about these whales’ migratory timing and routes.

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Knowledge of the local and migratory movements of humpback whales (Megaptera novaeangliae) from New Caledonia is very limited. To investigate this topic, we attached satellite-monitored tags to 12 whales off southern New Caledonia. Tag longevity ranged from 1 to 52 days (X = 22.5 days). Tagged whales generally moved to the south or southeast, with several spending time in a previously unknown seamount habitat named Antigonia before resuming movement, generally toward Norfolk Island or New Zealand. However, 1 female with a calf traveled the entire length of the western coast of New Caledonia (~450 km) and then west in the direction of the Chesterfield Reefs, a 19th century American (“Yankee”) whaling ground. None of the New Caledonia whales traveled to or toward eastern Australia, which is broadly consistent with the low rate of interchange observed from photo-identification comparisons between these 2 areas. The connections between New Caledonia and New Zealand, together with the relatively low numbers of whales seen in these places generally, support the idea that whales from these 2 areas constitute a single population that remains small and unrecovered.

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Springer et al. (2003) contend that sequential declines occurred in North Pacific populations of harbor and fur seals, Steller sea lions, and sea otters. They hypothesize that these were due to increased predation by killer whales, when industrial whaling’s removal of large whales as a supposed primary food source precipitated a prey switch. Using a regional approach, we reexamined whale catch data, killer whale predation observations, and the current biomass and trends of potential prey, and found little support for the prey-switching hypothesis. Large whale biomass in the Bering Sea did not decline as much as suggested by Springer et al., and much of the reduction occurred 50–100 yr ago, well before the declines of pinnipeds and sea otters began; thus, the need to switch prey starting in the 1970s is doubtful. With the sole exception that the sea otter decline followed the decline of pinnipeds, the reported declines were not in fact sequential. Given this, it is unlikely that a sequential megafaunal collapse from whales to sea otters occurred. The spatial and temporal patterns of pinniped and sea otter population trends are more complex than Springer et al. suggest, and are often inconsistent with their hypothesis. Populations remained stable or increased in many areas, despite extensive historical whaling and high killer whale abundance. Furthermore, observed killer whale predation has largely involved pinnipeds and small cetaceans; there is little evidence that large whales were ever a major prey item in high latitudes. Small cetaceans (ignored by Springer et al.) were likely abundant throughout the period. Overall, we suggest that the Springer et al. hypothesis represents a misleading and simplistic view of events and trophic relationships within this complex marine ecosystem.