Whale meat

From Wikipedia, the free encyclopedia

Raw whale meat in Norway

 

Whale meat on sale at Tsukiji fish market in Tokyo in 2008

 

Whale meat on sale at the fish market in Bergen, Norway, in 2012

 

A beluga whale is flensed for its maktaaq which is an important source of vitamin C in the diet of some Inuit.

 

Whale meat, broadly speaking, may include all cetaceans (whales, dolphins, porpoises) and all parts of the animal: muscle (meat), organs (offal), and fat (blubber). There is relatively little demand for it, compared to farmed livestock, and commercial whaling, which has faced opposition for decades, continues today in very few countries (mainly Iceland, Japan, Norway), although whale meat used to be eaten across Western Europe and colonial America. However, wherever dolphin drive hunting and aboriginal whaling exist, marine mammals are eaten locally as part of the subsistence economy: in the Faroe Islands; in the circumpolar Arctic (the Inuit in Canada and Greenland, related peoples in Alaska, the Chukchi people of Siberia); other indigenous peoples of the United States (including the Makah people of the Pacific Northwest); in St. Vincent and the Grenadines (mainly on the island of Bequia); in a couple of villages in Indonesia; in certain South Pacific islands.

Like horse meat, for some cultures whale meat is taboo, or a food of last resort, e.g. in times of war, whereas in others it is a delicacy and a culinary centrepiece. Indigenous groups contend that whale meat represents their cultural survival. Its consumption has been denounced by detractors on wildlife conservation, toxicity, and animal rights grounds. Whale meat can be prepared in various ways, including salt-curing, which means that consumption is not necessarily restricted to coastal communities.

History

Native American whalers removing strips of flesh from a whale carcase at Neah Bay, Washington, 1910

 

Whales were hunted in European waters throughout the Middle Ages for their meat and oil. Under Catholicism, aquatic creatures were generally considered "fish"; therefore whale was deemed suitable for eating during Lent and other "lean periods". An alternative explanation is that the Church considered "hot meat" to raise the libido, making it unfit for holy days. Parts submerged in water, such as whale or beaver tails, were considered "cold meat."

Eating whale meat did not end with the Middle Ages in Europe, but rather, whale stock in nearby oceans collapsed due to overexploitation, especially the right whales around the Bay of Biscay. Thus European whalers (the Basques, especially, were known for their expertise) had to seek out the New World to catch whales. The Dutch (Flemish) were also active in the whaling commerce during the Middle Ages, and a number of records regarding the trafficking of whalemeat and taxation on it occur from historical Flanders (extending to cities like Arras or Calais in the département of Pas de Calais).

French surgeon Ambroise Paré (died 1590) wrote that "the flesh has no value, but the tongue is soft and delicious and therefore salted; likewise, the blubber, which is distributed across many provinces, and eaten with peas during Lent". This blubber, known as craspois or lard de carême was food for the poorer strata on the continent. The whaling industry in North America may have supplied rendered fat, partly for consumption in Europe.

In early America, whalemen may have eaten blubber after rendering, which they termed "cracklings" or "fritters", said to be crunchy like toast; these were certainly reused as fuel chips to boil down the fat. Colonial America also more commonly consumed the meat and other portions of the "blackfish" (or pilot whale). However, by the beginning of large-scale commercial whaling, whale meat was not consumed by the general American public, as it was not seen as fit for consumption by so-called civilized peoples.

Species hunted

Minke whale is one of the most common species still hunted in substantial numbers.^{[citation needed]} Baleen whales other than the minke are endangered, though they are taken in numbers by indigenous peoples who traditionally hunt them, and more lately, the whaling nations have resumed hunting larger baleen whales openly.

In 1998-1999, Harvard researchers published their DNA identifications of samples of whalemeat they obtained in the Japanese market, and found that mingled among the presumably legal (i.e. minke whale meat) was a sizeable proportion of dolphin and porpoise meats, and instances of endangered species such as fin whale and humpback whale. (Blue whale DNA was also detected in the study, but researchers have attributed those findings to crossbreeding with fin whales, and that view has since been strengthened.)

In recent years Japan has resumed taking North Pacific fin whale and sei whales in their "research whaling". The fin whales are highly desired because they yield arguably the best quality of tail meat (onomi). Japanese research vessels refer to the harvested whale meat as incidental byproducts which have resulted from study.

In Japan, the research whale meat was sold at officially published prices, but since 2011 an auction bid system has been adopted and actual realized prices have not been posted. 

Cut of whale meat for sale	1998 (minke whale) official prices (converted to yen/kg)	2011 (Bryde's whale) reference price for bidding (yen/kg)
Special selection red meat	n/a	7000
Special grade red meat	4640	4500
1st grade red meat	3270	1700
2nd grade red meat	140	n/a
1st grade unesu (baleen whale underbelly, used for bacon)	5860	3000
2nd grade unesu	4380	2600

The channels through which premium cuts such as fin whale tail meat are sold remain opaque. A report by one of the Greenpeace Japan activists who intercepted whale meat package deliveries got no further than the sentiment by one restaurateur that it would take Nagatachō (i.e. high government) connections to get it.

Regions

In places such as Norway, Iceland, and Alaska, whale meat may be served without seasoning. However, it can also be cured or marinated, or made into jerky.

Norway

In Norway, whale meat was a cheap and common food until the 80s. It could be used in many ways but was often cooked in a pot with lid in a little water so that broth was created and then served with potatoes and vegetables, often with flatbrød at the side.

Greenland

The consumption of whale meat by the Inuit people in Greenland is part of their culture. However, in 2010, tourists also have begun to consume the meat. A Whale and Dolphin Conservation Society (WDCS) investigation has documented the practice of commercial wholesalers commissioning subsistence whalers to supply the demand by supermarkets. Whale products in Greenland are sold in 4-star hotels.

Japan

Sashimi of whale meat

 

The fluke (oba) which are thinly sliced and rinsed (sarashi kujira). Topped with vinegar-miso sauce

 

Whale bacon

 

Icelandic fin whale meat on sale in Japan in 2010

 

Whales have been hunted for meat in Japan since before 800 AD. After World War II, due to damage to Japan's infrastructure, whale meat became an important source of proteins.

In modern-day Japan, two cuts of whale meat are usually created: the belly meat and the tail meat. In the early 19th century, 70 different cuts were known. People still call the belly and tail cuts by their special whalemeat names, and also, different parts of the body such as the tongue retain their jargon names (see below). The tail meat is not the same as the fluke (tail flipper), and they go by different names. 

As previously mentioned, different cuts of whale meat have specialised names. The belly meat, in the striped bellows-like underbelly of baleen whales "from the lower jaw to the navel", is called unesu (ウネス（畝須）) and is known for being made into whale bacon.

The prized tail meat, called onomi (尾の身) or oniku (尾肉) are two strips of muscle that run from the dorsal to the base of the fluke. The tail meat is regarded as marbled, and is eaten as sashimi or tataki. Even Masanori Hata (aka Mutsugorō) a zoologist author and animal shelter operator has extolled the delicacy of the tail meat. It can only be derived from larger baleen whales, and the fin whale's meat has been considered superior. When the ban on this species was in place and Japan ostensibly complied, what was claimed to be genuine fin whale was still available, and legitimized as "grandfathered" goods, i.e., frozen stock from animals caught when still legal. In the past when blue whale hunting was still conducted by all nations, its tail fin was served in Japan.

The other portions are labelled lean, or "red meat" (赤肉 akaniku) and command much lower prices than the tail.

The fluke or tail flipper is referred to as either oba (尾羽) or obake (尾羽毛). After being cured in salt it is thinly sliced, scalded with hot water and rinsed, and served as sarashi kujira (pictured).

The tongue, called saezuri (さえずり) is often processed and used in high-end oden. The fried skin after the blubber is called koro, and analogous to "fritter/crackling". 

The Japanese article under 鯨肉 provides a more extensive list, which includes the intestines, sex organs, and other offal.

• Harihari-nabe is a hot pot dish, consisting of whalemeat boiled with mizuna.
• Sashimi of Abura-sunoko is striped layers of meat made from the root of the flippers.
• Udemono, consists of innards that have been boiled and sliced.

Some other dishes are: cubed and grilled blubber, cartilage salads, and whale skin stew.

As of 2006, in Japan, 5,560 tons of whale meat worth ¥5.5 billion is sold in every year. The Japanese market has declined in recent years, with prices falling to $26 per kilogram in 2004, down $6 per kilogram from 1999. Fluke meat can sell for over $200 per kilogram, over three times the price of belly meat.

Greenpeace has alleged that some of the meat on sale is illegally sourced. They have claimed that it has been illegally smuggled from crew members of research ships and that more meat is caught than can be consumed by humans, with up to 20% of 2004's catch going unsold.

Native Alaskan communities

For thousands of years, Native Alaskans of the Arctic have depended on whale meat. The meat is harvested from legal, non-commercial hunts that occur twice a year in the spring and autumn. The meat is stored and eaten throughout the winter.

Tikiġaġmiut, Iñupiat living on the coast of Alaska, divided their catch into 10 sections. The fatty tail, considered to be the best part, went to the captain of the conquering vessel, while the less-desired sections were given to his crew and others that assisted with the kill.

The skin and blubber, known as muktuk, taken from the bowhead, beluga, or narwhal is also valued, and is eaten raw or cooked. Mikigaq is the fermented whale meat.

Faroe Islands

Whaling in the Faroe Islands in the North Atlantic has been practiced since about the time of the first Norse settlements on the islands. Around 1000 Long-finned Pilot Whales (Globicephala melaena) are killed annually, mainly during the summer. The hunts, called "grindadráp" in Faroese, are organized on a community level. 

Both the meat and blubber are stored and prepared in various ways, including Tvøst og spik. When fresh, the meat is often boiled. It can also be served as steak (grindabúffur). This dish comprises meat and blubber, which is salted and then boiled for an hour, served with potatoes. The meat can also be hung out to dry and then served in thin slivers. At parties some choose to serve "kalt borð" (cold table), which means a variety of cold food, which can include dried whale meat, dried blubber or blubber which is preserved in water with much salt in it, dried fish, dried sheep meat, etc. Traditionally, whale meat was preserved by hanging salted pieces (called "likkjur") outdoors under a roof to be dried in the wind. This method is still used today, particularly in villages. Today, both meat and blubber can also be stored in freezers.

In 2008, Faroe Islands Chief Medical Officer Høgni Debes Joensen and Pál Weihe of the Department of Public and Occupational Health recommended that pilot whales no longer be considered fit for human consumption due to the presence of DDT derivatives, PCBs and mercury in the meat. Their recommendation was based on research suggesting a correlation between mercury intake and the high rate of Parkinson's disease on the islands. As of 1 June 2011, the Faroese Food and Veterinary Authority has advised Faroe Islanders not to eat the kidney or liver of pilot whales, not to consume more than one serving per month, and, for women and girls, to refrain from eating blubber if they plan to have children and to refrain from whale meat entirely if they are breastfeeding, pregnant or planning to conceive in the following three months.

United Kingdom

During World War II the British Minister of Food introduced food rationing but allowed whale meat to be distributed 'off ration', i.e. without restriction. It was not popular because of the smell whilst cooking was deemed 'unpleasant', and the taste was considered 'bland' even when spiced.

During the post-World War II period, corned whale meat was available as an unrationed alternative to other meats. Sold under the name "whacon", the meat was described as "corned whalemeat with its fishy flavour removed", and was almost identical to corned beef, except "brownish instead of red". The Food Ministry emphasised its high nutritional value.

Toxicity

Tests have revealed that in whale meat sold in Japan, high levels of mercury and other toxins are present. A research study was conducted by Tetsuya Endo, Koichi Haraguchi and Masakatsu Sakata at the University of Hokkaido found high levels of mercury in the organs of whales, particularly the liver. They stated that "Acute intoxication could result from a single ingestion" of liver. The study found that liver samples for sale in Japan contained, on average, 370 micrograms of mercury per gram of meat, 900 times the government's limit. Levels detected in kidneys and lungs were approximately 100 times higher than the limit. The effect is due to the animal's trophic level, however, rather than its size. This means that there is a significant difference between the mercury levels in toothed whales and baleen whales, the former having a much higher concentration.

Environmental impact

Norwegian-based High North Alliance, has suggested that the carbon footprint resulting from eating whale meat is substantially lower than that of beef. Greenpeace has responded that, "The survival of a species is more important than lower greenhouse gas emissions from eating it." Many organizations, including Greenpeace and the Sea Shepherd Conservation Society, have criticised the whale trade for preying on endangered species, as studies have shown an alarming decrease in whale populations, which may significantly affect oceans and its foodchains, therefore it may affect lives in a foreseable future.

Anti-whaling efforts

Groups such as the Sea Shepherd Conservation Society have attempted to disrupt commercial whaling with varying degrees of success.

Habitat fragmentation

From Wikipedia, the free encyclopedia

Fragmentation and destruction of Great Ape habitat in Central Africa, from the GLOBIO and GRASP projects. Areas shown in black and red delineate areas of severe and moderate habitat loss, respectively.

 

Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes that slowly alter the layout of the physical environment (suspected of being one of the major causes of speciation),and human activity such as land conversion, which can alter the environment much faster and causes the extinction of many species. 

Deforestation and increased road-building in the Amazon Rainforest are a significant concern because of increased human encroachment upon wild areas, increased resource-extraction and further threats to biodiversity.

Definition

The term habitat fragmentation includes five discrete phenomena:

• Reduction in the total area of the habitat
• Decrease of the interior: edge ratio
• Isolation of one habitat fragment from other areas of habitat
• Breaking up of one patch of habitat into several smaller patches
• Decrease in the average size of each patch of habitat

"fragmentation ... not only causes loss of the amount of habitat, but by creating small, isolated patches it also changes the properties of the remaining habitat" (van den Berg et al. 2001). Habitat fragmentation is the landscape level of the phenomenon, and patch level process. Thus meaning, it covers; the patch areas, edge effects, and patch shape complexity.

In scientific literature, there is some debate whether the term "habitat fragmentation" applies in cases of habitat loss, or whether the term primarily applies to the phenomenon of habitat being cut into smaller pieces without significant reduction in habitat area. Scientists who use the stricter definition of "habitat fragmentation" per se would refer to loss of habitat area as "habitat loss" and explicitly mention both terms if describing a situation where the habitat becomes less connected and there is less overall habitat.

Causes

Natural causes

Evidence of habitat destruction through natural processes such as volcanism, fire, and climate change is found in the fossil record. For example, habitat fragmentation of tropical rainforests in Euramerica 300 million years ago led to a great loss of amphibian diversity, but simultaneously the drier climate spurred on a burst of diversity among reptiles.

Human causes

Habitat fragmentation is frequently caused by humans when native plants is cleared for human activities such as agriculture, rural development, urbanization and the creation of hydroelectric reservoirs. Habitats which were once continuous become divided into separate fragments. After intensive clearing, the separate fragments tend to be very small islands isolated from each other by cropland, pasture, pavement, or even barren land. The latter is often the result of slash and burn farming in tropical forests. In the wheat belt of central western New South Wales, Australia, 90% of the native vegetation has been cleared and over 99% of the tall grass prairie of North America has been cleared, resulting in extreme habitat fragmentation.

Endogenous vs. exogenous

There are two types of processes that can lead to habitat fragmentation. There are exogenous processes and endogenous processes. Endogenous are process that develop as a part of a species biology so they typically include changes in biology, behavior and interactions within or between species. Endogenous threats can result in changes to breeding patterns or migration patterns and are often triggered by exogenous processes. Exogenous processes are independent of species biology and can include habitat degradation, habitat subdivision or habitat isolation. These processes can have a substantial impact on endogenous processes by fundamentally altering species behavior. Habitat subdivision or isolation can lead to changes in dispersal or movement of species including changes to seasonal migration. These changes can lead to decrease in a density of species, increased competition or even increased predation.

Implications

Habitat Loss and Biodiversity

One of the major ways that habitat fragmentation affects biodiversity is by reducing the amount of suitable habitat available for organisms. Habitat fragmentation often involves both habitat destruction and the subdivision of previously continuous habitat. Plants and other sessile organisms are disproportionately affected by some types of habitat fragmentation because they cannot respond quickly to the altered spatial configuration of the habitat.

Habitat loss, which can occur through the process of habitat fragmentation, is considered to be the greatest threat to species. But, the effect of the configuration of habitat patches within the landscape, independent of the effect of the amount of habitat within the landscape (referred to as fragmentation per se), has been suggested to be small. A review of empirical studies found that, of the 381 reported significant effect of habitat fragmentation per se on species occurrences, abundances or diversity in the scientific literature, 76% were positive whereas 24% were negative. Despite these results, the scientific literature tends to emphasize negative effects more than positive effects. Positive effects of habitat fragmentation per se imply that several small patches of habitat can have higher conservation value than a single large patch of equivalent size. Land sharing strategies could therefore have more positive impacts on species than land sparing strategies.

Habitat fragmented by numerous roads near the Indiana Dunes National Lakeshore.

 

Area is the primary determinant of the number of species in a fragment and the relative contributions of demographic and genetic processes to the risk of global population extinction depend on habitat configuration, stochastic environmental variation and species features. Minor fluctuations in climate, resources, or other factors that would be unremarkable and quickly corrected in large populations can be catastrophic in small, isolated populations. Thus fragmentation of habitat is an important cause of species extinction. Population dynamics of subdivided populations tend to vary asynchronously. In an unfragmented landscape a declining population can be "rescued" by immigration from a nearby expanding population. In fragmented landscapes, the distance between fragments may prevent this from happening. Additionally, unoccupied fragments of habitat that are separated from a source of immigrants by some barrier are less likely to be repopulated than adjoining fragments. Even small species such as the Columbia spotted frog are reliant on the rescue effect. Studies showed 25% of juveniles travel a distance over 200m compared to 4% of adults. Of these, 95% remain in their new locale, demonstrating that this journey is necessary for survival.

Additionally, habitat fragmentation leads to edge effects. Microclimatic changes in light, temperature and wind can alter the ecology around the fragment, and in the interior and exterior portions of the fragment. Fires become more likely in the area as humidity drops and temperature and wind levels rise. Exotic and pest species may establish themselves easily in such disturbed environments, and the proximity of domestic animals often upsets the natural ecology. Also, habitat along the edge of a fragment has a different climate and favours different species from the interior habitat. Small fragments are therefore unfavourable for species which require interior habitat. The percentage preservation of contiguous habitats is closely related to both genetic and species biodiversity preservation. Generally a 10% remnant contiguous habitat will result in a 50% biodiversity loss.

Informed Conservation

Habitat fragmentation is often a cause of species becoming threatened or endangered. The existence of viable habitat is critical to the survival of any species, and in many cases the fragmentation of any remaining habitat can lead to difficult decisions for conservation biologists. Given a limited amount of resources available for conservation is it preferable to protect the existing isolated patches of habitat or to buy back land to get the largest possible continuous piece of land. In rare cases a conservation reliant species may gain some measure of disease protection by being distributed in isolated habitats. This ongoing debate is often referred to as SLOSS (Single Large or Several Small).

One solution to the problem of habitat fragmentation is to link the fragments by preserving or planting corridors of native vegetation. In some cases, a bridge or underpass may be enough to join two fragments. This has the potential to mitigate the problem of isolation but not the loss of interior habitat. 

Another mitigation measure is the enlargement of small remnants in order to increase the amount of interior habitat. This may be impractical since developed land is often more expensive and could require significant time and effort to restore. 

The best solution is generally dependent on the particular species or ecosystem that is being considered. More mobile species, like most birds, do not need connected habitat while some smaller animals, like rodents, may be more exposed to predation in open land. These questions generally fall under the headings of metapopulations island biogeography.

Genetic Risks

As the remaining habitat patches are smaller, they tend to support smaller populations of fewer species. Small populations are at an increased risk of a variety of genetic consequences that influence their long-term survival. Remnant populations often contain only a subset of the genetic diversity found in the previously continuous habitat. In these cases, processes that act upon underlying genetic diversity, such as adaptation, have a smaller pool of fitness-maintaining alleles to survive in the face of environmental change. However in some scenarios, where subsets of genetic diversity are partitioned among multiple habitat fragments, almost all original genetic diversity can be maintained despite each individual fragment displaying a reduced subset of diversity.

Gene Flow and Inbreeding

Gene flow occurs when individuals of the same species exchange genetic information through reproduction. Populations can maintain genetic diversity through migration. When a habitat becomes fragmented and reduced in area, gene flow and migration is typically reduced. Fewer individuals will migrate into the remaining fragments, and small disconnected populations that may have once been part of a single large population will become reproductively isolated. Scientific evidence that gene flow is reduced due to fragmentation depends on the study species. While trees that have long-range pollination and dispersal mechanisms may not experience reduced gene flow following fragmentation, most species are at risk of reduced gene flow following habitat fragmentation.

Reduced gene flow, and reproductive isolation can result in inbreeding between related individuals. Inbreeding does not always result in negative fitness consequences, but when inbreeding is associated with fitness reduction it is called inbreeding depression. Inbreeding becomes of increasing concern as the level of homozygosity increases, facilitating the expression of deleterious alleles that reduce the fitness. Habitat fragmentation can lead to inbreeding depression for many species due to reduced gene flow. Inbreeding depression is associated with conservation risks, like local extinction.

Genetic Drift

Small populations are more susceptible to genetic drift. Genetic drift is random changes to the genetic make up of populations and always leads to reductions in genetic diversity. The smaller the population is, the more likely genetic drift will be a driving force of evolution rather than natural selection. Because genetic drift is a random process, it does not allow species to become more adapted to their environment. Habitat fragmentation is associated with increases to genetic drift in small populations which can have negative consequences for the genetic diversity of the populations. However, research suggests that some tree species may be resilient to the negative consequences of genetic drift until population size is as small as ten individuals or less.

Adaptation

In order for populations to evolve in response to natural selection, they must be large enough that natural selection is a stronger evolutionary force than genetic drift. Recent studies on the impacts of habitat fragmentation on adaptation in some plant species have suggested that organisms in fragmented landscapes may be able to adapt to fragmentation. However, there are also many cases where fragmentation reduces adaptation capacity because of small population size.

Examples of Impacted Species

Some species that have experienced genetic consequences due to habitat fragmentation are listed below:

Macquarie perch

• Macquaria australasica
• Fagus sylvatica 
• Betula nana
• Rhinella ornata 
• Ochotona princeps
• Uta stansburiana
• Plestiodon skiltonianus
• Sceloporus occidentalis
• Chamaea fasciata

Effect on Animal Behaviours

Although the way habitat fragmentation affects the genetics and extinction rates of species has been heavily studied, fragmentation has also been shown to affect species' behaviours and cultures as well. This is important because social interactions have the ability to determine and have an effect on a species' fitness and survival. Habitat fragmentation alters the resources available and the structure of habitats, as a result alters the behaviours of species and the dynamics between differing species. Behaviours affected can be within a species such as reproduction, mating, foraging, species dispersal, communication and movement patterns or can be behaviours between species such as predator prey relationships.

Predation Behaviours

Habitat fragmentation due to anthropogenic activities has been shown to greatly affect the predator-prey dynamics of many species by altering the amount of species and the members of those species. This affects the natural predator-prey relationships between animals in a given community and forces them to alter their behaviours and interactions, therefore resetting the so called "behavioral space race". The way in which fragmentation changes and re-shapes these interactions can occur in many different forms. Most prey species have patches of land that are refuge from their predators, allowing them the safety to reproduce and raise their young. Human introduced structures such as roads and pipelines alter these areas by facilitating predator activity in these refuges, increasing predator-prey overlap. The opposite could also occur in the favour of prey, increasing prey refuge and subsequently decreasing predation rates. Fragmentation may also increase predator abundance or predator efficiency and therefore increase predation rates in this manner. Several other factors can also increase or decrease the extent to which the shifting predator-prey dynamics affect certain species, including how diverse a predators diet is and how flexible habitat requirements are for predators and prey. Depending on which species are affected and these other factors, fragmentation and its resulting effects on predator-prey dynamics may contribute to a species extinction. In response to these new environmental pressures, new adaptive behaviours may be developed. Prey species may adapt to increased risk of predation with strategies such as altering mating tactics or changing behaviours and activities related to food and foraging.

Boreal Woodland Caribous

In the boreal woodland caribous of British Columbia the effects of fragmentation are clearly demonstrated. The species refuge area is peatland bog which has been interrupted by linear features such as roads and pipelines. These features have allowed their natural predators, the wolf and the black bear to more efficiently travel over landscapes and between patches of land. Since their predators can more easily access the caribous' refuge, the females of the species attempt to avoid the area, affecting their reproductive behaviours and offspring produced.

Communication Behaviours

Fragmentation affecting the communication behaviours of birds has been well studied in Dupont's Lark. The Larks primarily reside in regions of Spain and are a small passerine bird which use songs as a means of cultural transmission between members of the species. The Larks have two distinct vocalizations, the song and the territorial call. The territorial call is used by males to defend and signal territory from other male Larks and is shared between neighbouring territories when males respond to a rivals song. Occasionally it is used as a threat signal to signify an impending attack on territory. A large song repertoire can enhance a males ability to survive and reproduce as he has a greater ability to defend his territory from other males, and a larger number of males in the species means a larger variety of songs being transmitted. Fragmentation of the Dupont's Lark territory from agriculture, forestry and urbanization appears to have a large effect on their communication structures. Males only perceive territories of a certain distance to be rivals and so isolation of territory from others due to fragmentation leads to a decrease in territorial calls as the males no longer have any reason to use it or have any songs to match.

Forest fragmentation

Forest fragmentation is a form of habitat fragmentation where forests are reduced (either naturally or man-made) to relatively small, isolated patches of forest known as forest fragments or forest remnants. The intervening matrix that separates the remaining woodland patches can be natural open areas, farmland, or developed areas. Following the principles of island biogeography, remnant woodlands act like islands of forest in a sea of pastures, fields, subdivisions, shopping malls, etc. These fragments will then begin to undergo the process of ecosystem decay. 

Forest fragmentation also includes less subtle forms of discontinuities such as utility right-of-ways (ROWs). Utility ROWs are of ecological interest because they have become pervasive in many forest communities, spanning areas as large as 5 million acres in the United States. Utility ROWs include electricity transmission ROWs, gas pipeline and telecommunication ROWs. Electricity transmission ROWs are created to prevent vegetation interference with transmission lines. Some studies have shown that electricity transmission ROWs harbor more plant species than adjoining forest areas, due to alterations in the microclimate in and around the corridor. Discontinuities in forest areas associated with utility right-of-ways can serve as biodiversity havens for native bees and grassland species, as the right-of-ways are preserved in an early successional stage.

Implications

Forest fragmentation is one of the greatest threats to biodiversity in forests, especially in the tropics. The problem of habitat destruction that caused the fragmentation in the first place is compounded by

• the inability of individual forest fragments to support viable populations, especially of large vertebrates
• the local extinction of species that do not have at least one fragment capable of supporting a viable population
• edge effects that alter the conditions of the outer areas of the fragment, greatly reducing the amount of true forest interior habitat.

The effect of fragmentation on the flora and fauna of a forest patch depends on a) the size of the patch, and b) its degree of isolation. Isolation depends on the distance to the nearest similar patch, and the contrast with the surrounding areas. For example, if a cleared area is reforested or allowed to regenerate, the increasing structural diversity of the vegetation will lessen the isolation of the forest fragments. However, when formerly forested lands are converted permanently to pastures, agricultural fields, or human-inhabited developed areas, the remaining forest fragments, and the biota within them, are often highly isolated.

Forest patches that are smaller or more isolated will lose species faster than those that are larger or less isolated. A large number of small forest "islands" typically cannot support the same biodiversity that a single contiguous forest would hold, even if their combined area is much greater than the single forest. However, forest islands in rural landscapes greatly increase their biodiversity.

Approaches to understanding habitat fragmentation

Two approaches that are typically used to understand habitat fragmentation and its ecological impacts.

Species-oriented approach

The species-oriented approach focuses specifically on individual species and how they each respond to their environment and habitat changes with in it. This approach can be limited because it does only focus on individual species and does not allow for a broad view of the impacts of habitat fragmentation across species.

Pattern-oriented approach

The pattern-oriented approach is based on land cover and its patterning in correlation with species occurrences. One model of study for landscape patterning is the patch-matrix-corridor model developed by Richard Forman The pattern-oriented approach focuses on land cover defined by human means and activities. This model has stemmed from island biogeography and tries to infer causal relationships between the defined landscapes and the occurrence of species or groups of species within them. The approach has limitations in its collective assumptions across species or landscapes which may not account for variations amongst them.

Variegation Model

The other model is the variegation model. Variegated landscapes retain much of their natural vegetation but are intermixed with gradients of modified habitat.  This model of habitat fragmentation typically applies to landscapes that are modified by agriculture. In contrast to the fragmentation model that is denoted by isolated patches of habitat surrounded by unsuitable landscape environments, the variegation model applies to landscapes modified by agriculture where small patches of habitat remain near the remnant original habitat. In between these patches are a matrix of grassland that are often modified versions of the original habitat. These areas do not present as much of a barrier to native species.

Erethism (mad hatter disease)

From Wikipedia, the free encyclopedia

Mercury poisoning, chronic (neurological symptomatology)
Elemental mercury
Specialty	Medical toxicology

Erethism, also known as erethism mercurialis, mad hatter disease, or mad hatter syndrome, is a neurological disorder which affects the whole central nervous system, as well as a symptom complex derived from mercury poisoning. Erethism is characterized by behavioral changes such as irritability, low self-confidence, depression, apathy, shyness and timidity, and in some extreme cases with prolonged exposure to mercury vapors, delirium, personality changes and memory loss. People with erethism often have difficulty with social interactions. Associated physical problems may include a decrease in physical strength, "headaches, general pain, and tremors after exposure to metallic mercury" as well as an irregular heartbeat.

Mercury is an element that is found worldwide in soil, rocks, and water. People who get erethism are often exposed to mercury through their jobs. Higher risk jobs include construction, industrial work, and working in factories. Some elemental and chemical forms of mercury (vapor, methylmercury, inorganic mercury) are more toxic than other forms. The human fetus and medically compromised people (for example, patients with lung or kidney problems) are the most susceptible to the toxic effects of mercury.

Mercury poisoning can also occur outside of occupational exposures including in the home. Inhalation of mercury vapor may stem from cultural and religious rituals where mercury is sprinkled on the floor of a home or car, burned in a candle, or mixed with perfume. Due to widespread use and popular concern, the risk of toxicity from dental amalgam has been exhaustively investigated. It has conclusively been shown to be safe.

Historically, this was common among old England felt-hatmakers who had long-term exposure to vapors from the mercury they used to stabilize the wool in a process called felting, where hair was cut from a pelt of an animal such as a rabbit. The industrial workers were exposed to the mercury vapors, giving rise to the expression "mad as a hatter". Some believe that the character the Mad Hatter in Lewis Carroll's Alice in Wonderland is an example of someone suffering from erethism, but the origin of this account is unclear. The character was almost certainly based on Theophilus Carter, an eccentric furniture dealer who was well known to Carroll.

Signs and symptoms

Acute mercury exposure has given rise to psychotic reactions such as delirium, hallucinations, and suicidal tendency. Occupational exposure has resulted in erethism, with irritability, excitability, excessive shyness, and insomnia as the principal features of a broad-ranging functional disturbance. With continuing exposure, a fine tremor develops, initially involving the hands and later spreading to the eyelids, lips, and tongue, causing violent muscular spasms in the most severe cases. The tremor is reflected in the handwriting which has a characteristic appearance. In milder cases, erethism and tremor regress slowly over a period of years following removal from exposure. Decreased nerve conduction velocity in mercury-exposed workers has been demonstrated. Long-term, low-level exposure has been found to be associated with less pronounced symptoms of erethism, characterized by fatigue, irritability, loss of memory, vivid dreams, and depression (WHO, 1976).

The man affected is easily upset and embarrassed, loses all joy in life and lives in constant fear of being dismissed from his job. He has a sense of timidity and may lose self control before visitors. Thus, if one stops to watch such a man in a factory, he will sometimes throw down his tools and turn in anger on the intruder, saying he cannot work if watched. Occasionally a man is obliged to give up work because he can no longer take orders without losing his temper or, if he is a foreman, because he has no patience with men under him. Drowsiness, depression, loss of memory and insomnia may occur, but hallucinations, delusions and mania are rare.

The most characteristic symptom, though it is seldom the first to appear, is mercurial tremor. It is neither as fine nor as regular as that of hyperthyroidism. It may be interrupted every few minutes by coarse jerky movements. It usually begins in the fingers, but the eyelids, lips and tongue are affected early. As it progresses it passes to the arms and legs, so that it becomes very difficult for a man to walk about the workshop, and he may have to be guided to his bench. At this stage the condition is so obvious that it is known to the layman as "hatter's shakes."

Buckell et al, Chronic Mercury Poisoning (1946)

Effects of chronic occupational exposure to mercury, such as that commonly experienced by affected hatters, include mental confusion, emotional disturbances, and muscular weakness. Severe neurological damage and kidney damage can also occur. Neurological effects include Korsakoff's dementia and erethism (the set of neurological symptoms characteristically associated with mercury poisoning). Signs and symptoms can include red fingers, red toes, red cheeks, sweating, loss of hearing, bleeding from the ears and mouth, loss of appendages such as teeth, hair, and nails, lack of coordination, poor memory, shyness, insomnia, nervousness, tremors, and dizziness. A survey of exposed U.S. hatters revealed predominantly neurological symptomatology, including intention tremor. After chronic exposure to the mercury vapours, hatters tended to develop characteristic psychological traits, such as pathological shyness and marked irritability (box). Such manifestations among hatters prompted several popular names for erethism, including "mad hatter disease", "mad hatter syndrome", "hatter's shakes" and "Danbury shakes".

History among hatters

Some of the steps in the manufacture of felt hats are illustrated in this image from 1858.

 

A man working in hat manufacture with no protective equipment, putting him at risk for mercury poisoning

 

Especially in the 19th century, inorganic mercury in the form of mercuric nitrate was commonly used in the production of felt for hats. During a process called carroting, in which furs from small animals such as rabbits, hares or beavers were separated from their skins and matted together, an orange-colored solution containing mercuric nitrate was used as a smoothing agent. The resulting felt was then repeatedly shaped into large cones, shrunk in boiling water and dried. In treated felts, a slow reaction released volatile free mercury. Hatters (or milliners) who came into contact with vapours from the impregnated felt often worked in confined areas.

Use of mercury in hatmaking is thought to have been adopted by the Huguenots in 17th-century France, at a time when the dangers of mercury exposure were already known. This process was initially kept a trade secret in France, where hatmaking rapidly became a hazardous occupation. At the end of the 17th century the Huguenots carried the secret to England, following the revocation of the Edict of Nantes. During the Victorian era the hatters' malaise became proverbial, as reflected in popular expressions like "mad as a hatter" and "the hatters' shakes".

The first description of symptoms of mercury poisoning among hatters appears to have been made in St Petersburg, Russia, in 1829. In the United States, a thorough occupational description of mercury poisoning among New Jersey hatters was published locally by Addison Freeman in 1860. Adolph Kussmaul's definitive clinical description of mercury poisoning published in 1861 contained only passing references to hatmakers, including a case originally reported in 1845 of a 15-year-old Parisian girl, the severity of whose tremors following two years of carroting prompted opium treatment. In Britain, the toxicologist Alfred Swaine Taylor reported the disease in a hatmaker in 1864.

In 1869, the French Academy of Medicine demonstrated the health hazards posed to hatmakers. Alternatives to mercury use in hatmaking became available by 1874. In the United States, a hydrochloride-based process was patented in 1888 to obviate the use of mercury, but was ignored.

In 1898, legislation was passed in France to protect hatmakers from the risks of mercury exposure. By the turn of the 20th century, mercury poisoning among British hatters had become a rarity.

Picture postcard of a hat factory in Danbury (postmarked 1911)

 

In the United States, the mercury-based process continued to be adopted until as late as 1941, when it was abandoned mainly due to the wartime need for the heavy metal in the manufacture of detonators. Thus, for much of the 20th century mercury poisoning remained common in the U.S. hatmaking industries, including those located in Danbury, Connecticut (giving rise to the expression the "Danbury shakes").

Another 20th-century cohort of affected hatmakers has been studied in Tuscany, Italy.

Hatters of New Jersey

The experience of hatmakers in New Jersey is well documented and has been reviewed by Richard Wedeen. In 1860, at a time when the hatmaking industry in towns such as Newark, Orange and Bloomfield was growing rapidly, a physician from Orange called J. Addison Freeman published an article titled "Mercurial Disease Among Hatters" in the Transactions of the Medical Society of New Jersey. This groundbreaking paper provided a clinical account of the effects of chronic mercury poisoning among the workforce, coupled with an occupational description of the use of mercuric nitrate during carroting and inhalation of mercury vapour later in the process (during finishing, forming and sizing). Freeman concluded that "A proper regard for the health of this class of citizens demands that mercury should not be used so extensively in the manufacture of hats, and that if its use is essential, that the hat finishers' room should be large, with a high ceiling, and well ventilated." Freeman's call for prevention went unheeded. 

In 1878, an inspection of 25 firms around Newark conducted by Dr L. Dennis on behalf of the Essex County Medical Society revealed "mercurial disease" in 25% of 1,589 hatters. Dennis recognized that this prevalence figure was probably an underestimate, given the workers' fear of being fired if they admitted to being diseased. Although Dennis did recommend the use of fans in the workplace he attributed most of the hatters' health problems to alcohol abuse (thus using the stigma of drunkenness in a mainly immigrant workforce to justify the unsanitary working conditions provided by employers).

The surprise is that men can be induced to work at all in such death producing enclosures. It is hard to believe that men of ordinary intelligence could be so indifferent to the ordinary laws of health... It does not seem to have occurred to them that all the efforts to keep up wages... [are] largely offset by the impairment of their health, due to neglect of proper hygienic regulations of their workshops... And when the fact of the workmen in the sizing room, who stand in water, was mentioned, and the simple and inexpensive means by which it could be largely avoided was spoken of, the reply was that it would cost money and hat manufacturers did not care to expend money for such purposes, if they could avoid it. Bishop, Annual Report of the Bureau of Statistics of Labor and Industries of New Jersey (1890)

Some voluntary reductions in mercury exposure were implemented after Lawrence T. Fell, a former journeyman hatter from Orange who had become a successful manufacturer, was appointed Inspector of Factories in 1883. In the late nineteenth century, a pressing health issue among hatters was tuberculosis. This deadly communicable disease was rife in the extremely unhygienic wet and steamy enclosed spaces in which the hatters were expected to work (in its annual report for 1889, the New Jersey Bureau of Labor and Industries expressed incredulity at the conditions—see box). Two-thirds of the recorded deaths of hatters in Newark and Orange between 1873 and 1876 were caused by pulmonary disease, most often in men under 30 years of age, and elevated death rates from tuberculosis persisted into the twentieth century. Consequently, public health campaigns to prevent tuberculosis spreading from the hatters into the wider community tended to eclipse the issue of mercury poisoning. For instance, in 1886 J. W. Stickler, working on behalf of the New Jersey Board of Health, promoted prevention of tuberculosis among hatters, but deemed mercurialism "uncommon", despite having reported tremors in 15–50% of the workers he had surveyed.

While hatters seemed to regard the shakes as an inevitable price to pay for their work rather than a readily preventable disease, their employers professed ignorance of the problem. In a 1901 survey of 11 employers of over a thousand hatters in Newark and Orange, the head of the Bureau of Statistics of New Jersey, William Stainsby, found a lack of awareness of any disease peculiar to hatters apart from tuberculosis and rheumatism (though one employer remarked that "work at the trade develops an inordinate craving for strong drink").

By 1934 the U.S. Public Health Service estimated that 80% of American felt makers had mercurial tremors. Nevertheless, trade union campaigns (led by the United States Hat Finishers Association, originally formed in 1854) never addressed the issue and, unlike in France, no relevant legislation was ever adopted in the United States. Instead, it seems to have been the need for mercury in the war effort that eventually brought to an end the use of mercuric nitrate in U.S. hatmaking; in a meeting convened by the U.S. Public Health Service in 1941, the manufacturers voluntarily agreed to adopt a readily available alternative process using hydrogen peroxide.

"Mad as a hatter"

While the name of Lewis Carroll's Mad Hatter may contain an allusion to the hatters' syndrome, the character itself appears to have been based on an eccentric furniture dealer.

Although the expression "mad as a hatter" was associated with the syndrome, the origin of the phrase is uncertain.

Lewis Carroll's iconic Mad Hatter character in Alice's Adventures in Wonderland displays markedly eccentric behavior, which includes taking a bite out of a teacup. Carroll would have been familiar with the phenomenon of dementia among hatters, but the literary character is thought to be directly inspired by Theophilus Carter, an eccentric furniture dealer who did not show signs of mercury poisoning.

The actor Johnny Depp has said of his portrayal of a carrot-orange haired Mad Hatter in Tim Burton's 2010 film, Alice in Wonderland that the character "was poisoned ... and it was coming out through his hair, through his fingernails and eyes".