Exploitation Of Marine Mammals Research Articles

Holocene climate change shifted Southern Ocean biogeochemical cycling and predator trophic dynamics

AbstractStudies of Antarctic paleo‐archives have produced conflicting hypotheses on the relative impact of long‐term climate change and historic exploitation of marine mammals on Southern Ocean krill predator foraging ecology. We disentangle these hypotheses using amino acid stable isotope analysis on a 7000‐yr Holocene archive of Adélie penguin (Pygoscelis adeliae) eggshells to differentiate variation in diet and trophic dynamics from baseline biogeochemical cycling as drivers of the rapid decline in krill predator bulk tissue δ15N values in recent centuries. Contrary to previous hypotheses suggesting solely trophic dynamic mechanisms as drivers of this decline, we identified an abrupt decline in source amino acid δ15N values, indicative of major changes in biogeochemical cycling at the base of the Southern Ocean food web that mirrored the decline in penguin bulk tissue δ15N values. These abrupt shifts in penguin δ15N values and associated biogeochemical cycling aligned with climatic events during the Little Ice Age that decreased surface δ15NNO3−, likely connected to a proposed increase in Ekman upwelling via a southward migration of the Westerlies. This baseline shift was in addition to a long‐term, gradual decline in penguin trophic position over the Holocene that began prior to both recent anthropogenic climate change and a proposed “krill‐surplus” following historic marine mammal exploitation in the 19th and 20th centuries. In resolving these outstanding hypotheses about drivers of Southern Ocean food web dynamics, this study emphasizes the fundamental importance of climate‐induced variability in biogeochemical cycling on ecological processes and improves the ability of paleo‐archives to inform the ecological consequences of future environmental change in the Southern Ocean.

Extensive woodland pasturing supported Pitted Ware Complex livestock management systems: Multi-stable isotope evidence from a Neolithic interaction zone

Middle Neolithic Pitted Ware Complex (PWC) groups throughout the Baltic coastal areas of Scandinavia almost exclusively exploited marine resources for their subsistence. However, Pitted Ware communities inhabiting eastern Jutland (Denmark) also heavily relied on domesticated livestock, reflecting their close contacts and interactions with neighboring Funnel Beaker agriculturalists. Whether or not these domesticates were managed using husbandry practices designed to intensively enhance livestock production or herded using more extensive management strategies that may have better articulated with seal hunting, shellfish gathering, and fishing activities remains unknown. Here, multi-stable isotopic analyses conducted on bone collagen and enamel apatite from wild and domesticated animal species recovered from Pitted Ware sites in Djursland indicate that hunters regularly sought prey that roamed in deeply canopied forests but extensively pastured their livestock under lightly canopied woodlands while also grazing some animals in more open habitats at moderately high stocking rates. Cattle may have been grazed on crop stubble after the summer harvest but were not fed grassy hay or agricultural by-products during the winter season. Instead, they were provided with leaf fodder sourced from diverse woodland pastures. The use of extensive pasturing regimes for livestock by PWC groups fitted well with the intensive exploitation of marine mammals, fishes, and shellfish as part of a highly resilient, sustainable subsistence complex.

Prehistoric and historic exploitation of marine mammals in the Black Sea

The recent exploitation of marine species is relatively well documented and understood in terms of impacts on species abundance, distribution, and resource use. In contrast, ancient exploitation of marine mammals remains poorly documented; in part, because a detailed meta-analysis of their presence in the zooarchaeological record is lacking. This is true in the Black Sea, where cetaceans are reported in the zooarchaeological record but have not yet been studied comprehensively. Here, we synthesize all available published and unpublished zooarchaeological data from 27 sites around the Black Sea, dating from the Mesolithic and Neolithic periods (6500-6000 BCE) to the Medieval period (641–1475 CE), to document the extent and nature of the exploitation of the Black Sea cetacean species. The results suggest that cetacean exploitation was practised continuously in the Black Sea over a period of 8500 years from the Neolithic through to the Medieval period. This suggests a much longer history of marine mammal exploitation in the Black Sea than previously understood, pushing back the timeline of human impacts on the Black Sea marine fauna.

Past and present utilisation of marine mammals in Grenada, West Indies

The exploitation of marine mammals in Grenada dates back to pre-Columbian times. Whaling ships visited Grenadian waters in the 19th century and during the 1920s there was a short-lived attempt to develop a local, modern whaling industry. Since then no exploitative interactions between Grenadians and marine mammals had taken place, until the 1990s when two whalewatching operations were established.

“This is the way”: Knowledge networks and toolkit specialization in the circumpolar coastal landscapes of western Alaska and Tierra del Fuego

One relevant dimension through which human populations articulate their occupation of the landscape involves the accumulation and interpersonal transmission of information pertaining to the spatio-temporal distribution, accessibility, and desirability of resources. The high productivity and resource diversity of coastal circumpolar landscapes enables them to sustain larger hunter-gatherer populations throughout the year. In circumpolar landscapes, marine mammals are a particularly highly ranked resource, as major sources of essential fats, proteins, and other nutrients. The adoption of specialized toolkits for marine mammal exploitation in open waters, encompassing watercraft and detachable harpoons, would have ensured that marine mammal hunting was a particularly rewarding and predictable endeavor. The first consistent adoption of toggling harpoons in southwestern Alaska is documented primarily at the height of the cold Neoglacial (ca. 4500–2500 BP), mirroring trends along the western Bering Sea coast. While maritime resource exploitation in northwestern Alaska also appears to have begun during the Neoglacial—particularly in the Kotzebue Sound area—specialized technological adaptations reflecting full-time maritime adaptations became more prominent in the wider region during the subsequent warmer period, in the context of population growth and increasing social connectivity. In contrast, the appearance of detachable harpoons at sites in the Beagle Channel (southern Tierra del Fuego) does not appear to be associated with any significant climatic changes, developing locally around 6500 BP after an initial period of human settlement in the region which lacked such adaptations. Therefore, we argue that the pathways toward the adoption of specialized toolkits enabling a maritime-oriented subsistence strategy in circumpolar coastal environments emerged primarily as the outcome of the consolidation of knowledge networks derived from the habituation of hunter-gatherer-fisher communities to predictable ecological conditions during periods in which the coastal landscapes they inhabited had become relatively stable.

Examining the potential conflict between sea otter recovery and Dungeness crab fisheries in California

Human exploitation of marine mammals led to precipitous declines in many wild populations within the last three centuries. Legal protections enacted throughout the 20th century have enabled the recovery of many of these species and some recoveries have resulted in conflict with humans for shared resources. With legal protections and reintroduction programs, the southern sea otter (Enhydra lutris nereis) has returned to portions of its former range from which it had been extirpated for decades, causing concern that the Dungeness crab (Cancer magister) fishery could be negatively affected by increasing otter range and population size. The Dungeness crab fishery is one of the most valuable in California, and these crabs are a known prey item of sea otters. We examine sea otter population growth by port region in relation to Dungeness crab catch using landing receipts since the early 1980s. We find Dungeness crab landings and fishing success, as measured by landings per trip receipt, increased across all ports. In the most recent decade, we observed slower growth in fishing success in northern ports where otters were absent, relative to southern ports where sea otters exist and their populations have grown. In ports where otters were present, fishing success was positively correlated with otter population size over time. Further, an extensive dataset of 83,000 sea otter foraging dives identified Dungeness crab to be less than 2% of the total diet. Though we find no evidence that sea otter populations impact the Dungeness crab fishery in California, other potential conflicts could be considered before expanding reintroduction programs.

Dolphins and Boats: When Is a Disturbance, Disturbing?

Globally, exploitation of marine mammals has shifted from hunting to viewing over the last few decades. While refraining from actively killing animals may have a positive effect on marine mammal populations, whale and dolphin watching can induce changes such as displacement from preferred habitat and disruption of foraging that may also have severe fitness costs. Under some circumstances, this non-lethal disturbance may affect populations in a manner similar to directed mortality. Here, we focus on inshore dolphin populations that are known to show short-term behavioural responses to boat approaches. Long-term fitness effects have only been clearly identified in a small number of these populations, and all share certain characteristics, i.e. closed, small and food limited. This raises the question of importance of context when considering the long-term effects of disturbance, since many dolphin populations may be open, large, and/or free from resource restriction. We explored the effect of disturbance based on the characteristics of populations using the population consequences of disturbance (PCoD) framework. PCoD was developed to link short-term changes in individual behaviour and physiology to presumed long-term effects on population dynamics. To ensure our scenarios were biologically plausible, they reflected the ecological context of four well-studied populations of dolphins, Doubtful Sound NZ, Sarasota Bay USA, Durban Bay SA and Jervis Bay AUS, in terms of their size, closure and food resources. We found that the characteristics of the populations being disturbed are important with regards to the level of disturbance that could be tolerated. Closed populations were most sensitive, while large, open populations with no food limitation appeared to be able to withstand a higher probability of disturbance. This implies that population characteristics should be accounted for when determining the suitability of whale and dolphin watching operations in a given area.

Dietary resilience among hunter-gatherers of Tierra del Fuego: Isotopic evidence in a diachronic perspective.

The native groups of Patagonia have relied on a hunter-gatherer economy well after the first Europeans and North Americans reached this part of the world. The large exploitation of marine mammals (i.e., seals) by such allochthonous groups has had a strong impact on the local ecology in a way that might have forced the natives to adjust their subsistence strategies. Similarly, the introduction of new foods might have changed local diet. These are the premises of our isotopic-based analysis. There is a large set of paleonutritional investigations through isotopic analysis on Fuegians groups, however a systematic exploration of food practices across time in relation to possible pre- and post-contact changes is still lacking. In this paper we investigate dietary variation in hunter-gatherer groups of Tierra del Fuego in a diachronic perspective, through measuring the isotopic ratio of carbon (∂13C) and nitrogen (∂15N) in the bone collagen of human and a selection of terrestrial and marine animal samples. The data obtained reveal an unexpected isotopic uniformity across prehistoric and recent groups, with little variation in both carbon and nitrogen mean values, which we interpret as the possible evidence of resilience among these groups and persistence of subsistence strategies, allowing inferences on the dramatic contraction (and extinction) of Fuegian populations.

The Appeal to Science and the Formation of Global Animal Law

In 2014, two landmark international legal decisions made a significant contribution to the development of international law on the protection of animals: the report of the Appellate Body of the World Trade Organization (WTO) in EC-Seal Products, and the judgment of the International Court of Justice (ICJ) in Whaling in the Antarctic: Australia v. Japan. Science plays a significant role in both decisions. In EC-Seal Products, the WTO Appellate Body ruled that the European Union’s ban on seal products was justifiable under Article XX(a) of GATT as a matter of public morals, because it was based on European citizens’ moral objections to cruelty in seal hunting – concerns that were validated in part based on reports and evidence from scientific experts. In Whaling in the Antarctic, the ICJ ruled that Japan’s whaling programme in the Southern Ocean is not ‘for purposes of scientific research’ within the meaning of the International Convention on the Regulation of Whaling because it is not ‘reasonable’ in relation to its research objectives. Both cases, as well as the broader international controversies over whaling and sealing in the context of which they arose, illustrate the persuasive power of the ‘appeal to science’: enlisting scientific objectivity and rigour to underpin the credibility of legal arguments and legal norms. But the role of science in both cases, while important, is only auxiliary. The questions that the WTO and the ICJ had to resolve were fundamentally legal ones concerning the interpretation of the relevant treaties. The cases also implicated more profound questions of policy and ethics at stake in international conflicts over the protection and the exploitation of marine mammals.

Deplete Locally, Impact Globally: Environmental History of Shore- Whaling in Barbados, W.I.~!2009-07-26~!2010-01-01~!2010-04-06~!

We give a detailed history of the exploitation of marine mammals in Barbados, which focused almost exclusively on humpback whales (Megaptera novaeangliae). We have reconstructed this history to better understand the impacts of human activities on the marine environment. Based on historical data, we demonstrate that whaling was a marginal activity financed by local elites who found it easy to transfer labor and tools from agricultural activities to shore- whaling. In spite of its marginal status, this activity not only depleted the local population of whales in a relatively short period of time, it also contributed to the species' global decline. Today, humpbacks can be considered locally absent. Barbados, like other former British colonies, exploited marine mammals through shore-whaling, unlike many Latin American nations, which pursued dolphin fisheries. Barbadian shore-whaling, like many other marine mammal exploitation practices elsewhere in the Caribbean, was heavily influenced by industrialized nations. This history provides important clues for whale management and recovery.

Application of lipid biomarker analysis to evaluate the function of ‘slab-lined pits’ in Arctic Norway

Gas chromatography–mass spectrometry (GC–MS) and bulk carbon isotope determinations have been performed on samples (‘cemented organic residues’, charcoal, sediment and fire-cracked rock) excavated from 12 slab-lined pits from various locations in Arctic Norway to test the premise that these archaeological features were used for the extraction of oil from the blubber of marine mammals, such as seal, whale and walrus. A wide range of lipid compound classes were detected especially in the cemented organic residues and in the charcoal samples. The presence of long-chain unsaturated and isoprenoid fatty acids together with oxidation and thermal alteration products of unsaturated acids such as dicarboxylic acids, dihydroxyfatty acids and ω-(o-alkylphenyl)alkanoic acids suggests that these features were used for marine oil extraction at elevated temperatures. Notably the location of the hydroxyl groups in the dihydroxyfatty acids provides a record of the positional isomer of the precursor fatty acid and allows confirmation that 11-docosenoic (cetoleic) acid, the most abundant C 22:1 isomer in marine oil, was a major component of the original lipid. Further information was provided by the presence of long-chain fatty acyl moieties in surviving triacylglycerols and the presence of cholesterol. A fungal metabolite, mycose (trehalose), was found in all samples apart from a fire-cracked rock and points to microbiological activity in the pits. Bulk isotope analysis conducted on the ‘cemented organic residues’ is consistent with modern reference samples of blubber and oil from seal and whale. These data provide clear analytical evidence of the function of slab-lined pits in the archaeological record and suggest widespread exploitation of marine mammals for producing oil for heating, lighting and myriad other uses in the past.

Inuit Economic Responses to Euro‑American Contacts: Southeast Baffin Island, 1824‑1940

First contacts between Inuit and European whalers on Cumberland Peninsula led to considerable movement of population after 1824. Whaling vessels aided the mobility of hunting groups and developed seasonal employment patterns. They also changed the material culture of Inuit hunting and the seasonal pattern of exploitation of marine mammals. Depletion of bowhead whales in the 1870s led the Inuit to diversify their hunting for trade, and diminished the number of whalers permanently living or seasonally visiting the region. The decline in ship-winterings increased the importance of permanent whaling stations as sources of ammunition and provisions. Collapse of the whaling industry and the outbreak of the First World War left most stations, including several new ones, under native management on behalf of British traders. In the 1920s the new Hudson's Bay Company post at Pangnirtung squeezed out less-efficient competition, concentrated on the white fox as the new fur staple, and reorganized production through small hunting camps. This paper examines the manner in which the Inuit facilitated some of these transitions and resisted others.

Environmental History of Marine Mammal Exploitation in Trinidad and Tobago, W.I., and its Ecological Impact

Abstract Marine mammal exploitation has been documented for the Caribbean in recent times for only a handful of countries. Based on those studies a complex image of how that exploitation has taken place has begun to emerge. In order to fully understand whaling, dolphin fisheries, and manatee hunting, we still need to ascertain patterns of exploitation for many of the island-nations in that part of the world. We present a comprehensive analysis of marine mammal utilisation for Trinidad and Tobago. Trinidad and Tobago has been characterised by land-based whaling, organised during most of the nineteenth century by local elites. Dolphin fisheries have been rare and restricted to by-catches. Trinidad has the last remaining population of manatees among the eastern Caribbean islands, which is composed of a small number of individuals confined to a small swamp. We compared the history, patterns, and results of this exploitation in Trinidad and Tobago with other neighbouring nations (Venezuela, Grenada, and St. Vincent and the Grenadines). As in other countries in the area that practised intense whaling, local populations of humpback whales have become virtually extinct in their waters. Culture, more than anything else, seems to be the force shaping the nature of marine mammal exploitation in the Caribbean, which has resulted in different histories and methods of exploitation for each one of the countries studied.

Ecosystem-Based Fisheries Management, Commercial Fisheries, Marine Mammals and the 2001 Reykjavik Declaration in the Context of International Law

AbstractThe current global crisis in marine capture fisheries contrasts sharply with the recovery of some stocks of marine mammals. Eventually this will have to lead to a re-evaluation of the preferential treatment that marine mammals now often enjoy. The widening support for ecosystem-based fisheries management (EBFM) and the growing insight in the interactions between marine mammals and commercial fisheries are expected to influence this evaluation. This article examines the role of marine mammals in the ecosystem with special emphasis on predation on commercial fisheries. Ample attention is devoted to the definition of EBFM, its legal status and issues of implementation. The 2001 Reykjavik Declaration on Responsible Fisheries in the Marine Ecosystem is used for illustration. One of the conclusions is that sufficient scientific research is required to substantiate positive effects that pre-emptive catches of marine mammals would have for (recovering) commercial fisheries. The regulatory objectives and international legal constraints relevant to marine mammals are moreover addressed to determine if the exploitation of marine mammals could be obligatory or "necessary".

Trans-Holocene Marine Mammal Exploitation on San Clemente Island, California: A Tragedy of the Commons Revisited

Occupied from ca. 7040 B.C. to A.D. 1400, the Eel Point Site (CA-SCLI-43) on San Clemente Island, California represents one of the longest sequences of near-continuous marine resource exploitation on the west coast of North America. Faunal remains suggest transitions from heavy exploitation of fur seals and sea lions during the early Holocene, to increased hunting of cetaceans at mid-Holocene, to a focus on sea otters and fish during the late Holocene. These trends are consistent with patterns of overexploitation and economic intensification on the California and Oregon mainland, but they also suggest watercraft-based hunting earlier on the island than elsewhere. Fur seal and sea lion bones mainly represent females and juveniles, indicating that exploitation of island rookeries was guided more by self-interest than by principles of game conservation. Two intervals of temporary site abandonment, ca. 6150–3970 B.C. and A.D. 1020–1400, were both followed by periods of increased marine mammal exploitation and may reflect intervals during which marine mammal populations rebounded. Broad-scale diachronic trends in the zooarchaeological remains do not correlate with flux in paleo-sea temperatures and are best interpreted as products of overhunting and increased use of watercraft over time.

Prehistoric Marine Mammal Hunting on California's Northern Channel Islands

Prehistoric marine mammal hunting is of interest to archaeologists worldwide because these animals were exploited by a wide range of coastal societies. Sorting out the roles of particular groups of fauna in prehistoric economies requires detailed attention to the analysis of the entire faunal assemblage. Although marine mammals typically provided large quantities of fat and protein and were desirable prey, they were not always central to the diets of the groups that exploited them, particularly in temperate zones. To evaluate effectively the importance of marine mammal exploitation, scholars should calculate the relative contribution of these animals to the economy, identify changes in hunting techniques, determine the relationship between fauna and other aspects of society, assess changing environmental conditions, and consider alternate explanations for those relationships. A large body of research on the northern Channel Islands of California demonstrates that fishing was relatively more important than marine mammal exploitation in subsistence and in stimulating sociopolitical and technological developments. Recent attempts to credit marine mammal hunting as a driving force in the invention of the plank canoe and the evolution of a chiefdom in the Santa Barbara Channel area misunderstand environmental factors and site histories in this region. Rather than assuming that a pan-Pacific Coast set of traditions existed to exploit these taxa, we see evidence of local and regional differences rooted in variable cultural settings, physiographic and oceanographic conditions, and available technologies. Data from the Santa Barbara Channel are used to explore the relationships among marine mammal use, sociological change, and environmental change.

Archaeological Excavations at Bon-Désir: Basque Presence in the St. Lawrence Estuary

The archaeological fieldwork on the Anse à La Cave site at Bon-Désir uncovered remains associated with the exploitation of marine mammals in the St. Lawrence estuary. Excavations revealed the presence of two series of ovens used for rendering marine mammal fat. These preliminary data contribute to our understanding of sites based on the seasonal exploitation of whales in North America by European fishermen. The environmental, historical, and archaeological data support the hypothesis of a Basque occupation in the St. Lawrence estuary, particularly on the Anse à La Cave site from perhaps as early as the end of the 16th century to the middle of the 18th century.

ZOOGEOGRAPHY OF OREGON COAST MARINE MAMMALS: THE LAST 3,000 YEARS

AbstractMammalian faunal remains recovered from three archaeological sites on the Oregon, U.S.A. coast provide strong evidence that 18th and 19th century commercial exploitation of marine mammals had major effects on the zoogeography and demography of those taxa. Zalophus californianus and Callorhinus ursinus bred and pupped along the Oregon coast between 3,000 and 100 yr ago. About 100 yr ago Eumetopias jubatus abandoned a major rookery that had been utilized since at least 400 yr ago. Phoca vitulina does not appear to have suffered major modifications to coastal use or demographic patterns in Oregon during the last 3,000 yr, although a minor incident of intensified utilization of one location about 1,000 yr ago is suggested. All age‐sex classes of Enhydra lutris lived on the Oregon coast until about A.D. 1900. Oregon's prehistoric remains of E. lutris display some dental characters similar to modern Alaskan specimens, and other dental characters similar to modern Californian specimens, conforming to a latitudinal dine reflected by historic specimens. Additional evidence for many of these observations is found in faunal remains recovered from archaeological sites on the coast of Vancouver Island, the Washington coast, and the northern California coast.

Conservation and the Antarctic environment: The working group reports of the joint IUCN/SCAR Symposium on the scientific requirements for Antarctic conservation

Six working groups were set up at the joint IUCN/SCAR Symposium on the scientific requirements for Antarctic conservation. These were charged with (i) identifying gaps in the scientific understanding of ecosystems that inhibit rational management, and (ii) considering whether present conservation practices were taking enough account of what is known of the region, particularly with regard to protected areas. There is still a need for synthesis and further work on stocks and the life history of krill in the pelagic ecosystem. Monitoring strategies are not clear and biomass determinations are difficult and costly. Information on squid is lacking. Although there is much information on higher consumers there is a gap in knowledge of dynamic ecological processes, particularly in winter. Studies of crabeater seals deserve priority. The network of existing protected areas is inadequate for preserving all species of birds, seals and whales; new criteria are needed for effective conservation. On land, the Agreed Measures provide an adequate framework for conservation, though additional steps are needed to ensure adherence to their provisions. Selection criteria are deficient. Additional measures are required; these include the establishment of Conservation Areas, general provision for the protection of biota, and a code of conduct for all activities. Exploitation of marine mammals (except the minke whale) has ceased. Monitoring whales presents difficulties. Fish stocks are significantly exploited and better monitoring is required. Prediction of trends in krill catches is difficult but there has been a large drop in krill fishing effort. Localised effects on predators could occur with catches of a few million metric tons. Commercial mineral exploitation in the Antarctic is a long way in the future but exploitation could result from political motives. There is a need for a data base for the design of investigations and impact assessment. Operational hazards need to be modelled in advance. It is important not to go too far too fast. Antarctica is unique in its control measures and their implementation. However, Specially Protected Areas lack management plans and management plans at Sites of Special Scientific Interest are not consistent. There are inadequate guidelines on the development of scientific stations. The coastal region must be regarded as critical habitat. A comprehensive conservation strategy is required with a broader network of protected areas giving full consideration to marine as well as terrestrial areas. Copies of the full working group reports have been deposited with IUCN and SCAR.