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The bushmeat chain reaction The bushmeat chain reaction
The illicit bushmeat trade involves a series of underlying socio-economic factors, but leads, with rising population densities, to local depletions of wildlife species, and increasingly inside protected areas.
19 Jun 2014 - by Riccardo Pravettoni, GRID Arendal
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Ringed seal pupping lair, with the pup in the lair and the female approaching the haul-out hole from the water Ringed seal pupping lair, with the pup in the lair and the female approaching the haul-out hole from the water
Ringed seals are the 'classic' Arctic seal in many regards, being found as far north as the Pole because of their ability to keep breathing holes open in ice that can reach 2 metres in depth. This species is certainly one of the most vulnerable of the high-Arctic seals to the declines in the extent or quality of sea ice because so many aspects of their life-history and distribution are tied to ice. Ringed seals also require sufficient snow cover...
01 Nov 2007 - by Robert Barnes, UNEP/GRID-Arendal
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Arctic pelagic food web Arctic pelagic food web
The marine animal food chain is very complex and multilayered as are most food chains. This is a quick reference to represent the complete food chain in regards to pelagic crustaceans and invertebrates.
28 Sep 2005 - by UNEP/GRID-Arendal
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Coastal Arctic food web (drift ice) Coastal Arctic food web (drift ice)
The coastal Arctic food web is closely related to drift ice conditions and seasonal use of shorelines by both terrestrial and sea mammals. Numerous species depend upon each other and the transport of food to and from the marine areas to the coast and inland. Indigenous peoples use most of the food chain and traditionally use both environments for hunting, fishing and gathering.
28 Sep 2005 - by UNEP/GRID-Arendal
4
Indications of structural changes in the marine ecosystem, catch ratios of predatory and plankton feeding fish Indications of structural changes in the marine ecosystem, catch ratios of predatory and plankton feeding fish
Three-quarters of fish stocks are currently exploited to the maximum extent, if not excessively. The Northeast Atlantic Ocean continues to exhibit declining catches, as well as a shift towards fish at lower levels in the food chain. This graphic illustrates the decline in the catch ratios of predatory and plankton-feeding fish in the Northeast Atlantic Ocean from 1950 to 1995.
17 May 2005 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Comb-jelly (Mnemiopsis leidyi) spreading through the Caspian Sea (invasive species) Comb-jelly (Mnemiopsis leidyi) spreading through the Caspian Sea (invasive species)
The comb jelly (Mnemiopsis leidyi) is well adapted to the habitat (salinity, temperature, and food range) and reproduces faster than endemic species. As it eats the same food as them, it has had a drastic effect on their numbers, upsetting the entire food chain. The jelly is an invasive species, brought from North America by ships.
04 Oct 2007 - by Philippe Rekacewicz, UNEP/GRID-Arendal
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Decline in trophic level of fisheries catch since 1950 Decline in trophic level of fisheries catch since 1950
A trophic level of an organism is its position in a food chain. Levels are numbered according to how far particular organisms are along the chain from the primary producers, to herbivores, to predators, to carnivores or top carnivores.
30 Nov 2007 - by Philippe Rekacewicz, Emmanuelle Bournay, UNEP/GRID-Arendal
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Losses in the food chain – from field to household consumption Losses in the food chain – from field to household consumption
i.e., before conversion of food to feed. After discounting the losses, conversions and wastage at the various stages, roughly 2,800 kcal are available for supply (mixture of animal and vegetal foods) and, at the end of the chain, 2,000 kcal on average – only 43% of the potential edible crop harvest – are available for consumption. (Source: Lundqvist et al., 2008).
02 Feb 2009 - by Hugo Ahlenius, UNEP/GRID-Arendal
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Ice coverage and primary production in the Arctic Ice coverage and primary production in the Arctic
Temperature changes may influence fish populations both directly, through shifts to areas with preferred temperature, and indirectly through the food supply and the occurrence of predators. The length of the ice-free period in the Arctic, for example, affects annual primary production, which is the basis of the food chain supporting populations of fish, sea mammals, and seabirds. As the amount of ice in the Arctic has considerably reduced since t...
17 Mar 2010 - by Hugo Ahlenius, GRID-Arendal & CAFF
4
Comb-jelly (Mnemiopsis leidyi) spreading through the Caspian Sea (invasive species) Comb-jelly (Mnemiopsis leidyi) spreading through the Caspian Sea (invasive species)
The comb jelly (Mnemiopsis leidyi) is well adapted to the habitat (salinity, temperature, and food range) and reproduces faster than endemic species. As it eats the same food as them, it has had a drastic effect on their numbers, upsetting the entire food chain. The jelly is an invasive species, brought from North America by ships.
21 May 2010 - by Philippe Rekacewicz, UNEP/GRID-Arendal
2
Polar bear sub-populations and pollution Polar bear sub-populations and pollution
There are thought to be between 20,000 and 25,000 bears in the world, which occur in19 relatively discrete sub-populations, some of which are shared between nations. Topping the food chain in the Arctic, the polar bear is exposed to high levels of pollutants that are magnified with each step higher in the food web (a process known as biomagnification). Recent studies have suggested that the immune system may be weaker in polar bears with higher l...
13 Oct 2010 - by Riccardo Pravettoni, UNEP/GRID-Arendal
4
Coastal Arctic food web (drift ice) Coastal Arctic food web (drift ice)
The coastal Arctic food web is closely related to drift ice conditions and seasonal use of shorelines by both terrestrial and sea mammals. Numerous species depend upon each other and the transport of food to and from the marine areas to the coast and inland. Indigenous peoples use most of the food chain and traditionally use both environments for hunting, fishing and gathering.
17 May 2005 - by UNEP/GRID-Arendal
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Fishing yield Fishing yield
Three-quarters of the world’s fish stocks are currently exploited to the maximum extent, if not in excess (FAO, 2000). This exploitation has had the following impacts: - A growing variety of fishery products are being exploited. Commercial fishermen are targeting progressively smaller species at lower levels of the food chain because the main predator species are being depleted. - Most of the world’s main fishing areas are close to full exploit...
26 Jan 2009 - by Phillippe Rekacewicz, February 2006
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