Alaskan Grizzly Bears & Salmon Migration | Animals - raznomir.info
This is an example of predator-prey relationship. a bear eats a fish. Bear Catching Fish Bear Catching Salmon, Panda, Bear Fishing, Salmon Fishing, Predator. Mutual Relationships with plants- A large number of grizzlies have a mutual relationship with berry producing plants. Many bears feed on. Overview of Relationships Between Bears, Wolves, and Moose in Alaska. Relationships between large predators and their prey in Alaska are complex, and no.
Specifically, wolves were rare in Interior Alaska between about andand during the s. During wolves may have succumbed to diseases brought in by sled dogs or to widespread poisoning. During the s, federal predator control agents reduced wolves by poisoning and aerial shooting. Wolves have been abundant and have occurred in all of their historic ranges in Alaska since state management began in about except for the Anchorage and Fairbanks areas, and the western Seward Peninsula.
Wolves are social animals that live in large family groups. Usually, only a single female per pack successfully raises pups, but depending upon the relationship of adult males and females in a wolf pack, multiple litters may occur in a single pack in a single year. Most pups born into a pack stay in the pack for at least one year, but virtually all have dispersed away from their natal pack by the age of 3.
Large packs of 20 or more wolves may occur in areas where food is abundant and pup survival is high.
High reproductive rates, high mortality rates and long distance dispersal behavior results in extensive gene flow within wolf populations and between wolf packs. In Alaska and other areas, if wolves are not hunted or trapped, most mortality is from intraspecific aggression fighting with other wolves.
Intensive Management in Alaska
In trapped wolf populations, natural mortality rates are often lower than in untrapped populations. In coastal areas of Alaska, where fox rabies is endemic, wolves are periodically reduced to low levels by rabies. LDDE does not present a biological problem — moose are not likely to become threatened, endangered or extinct due to predation.
The fact that the LDDE prevails in large areas does not usually present a management problem either. Interior Alaska is sparsely populated and access to moose populations is often poor. This means that hunting pressure is relatively light in many areas anyway. The LDDE can cause a management problem around villages, or in areas that have become important hunting areas for Alaskans near the road system. In these areas, people need or want to harvest more moose than the system can support.
In Alaska, moose are valuable to people as a source of food and income i.
This is why people often express the desire for predator control. In some areas, where there is a demand to increase moose harvests, it might be possible to harvest more moose by reducing bear predation.
Fishing Bears The bears generally catch salmon from rocks where the fish have to jump to reach the next level of the stream. Cubs develop their fishing technique by watching their mother, and some bears are better fishers than others.
Predator/Prey Relationships, Alaska Department of Fish and Game
Bears must eat about 25 fish a day to put on enough fat to survive the winter hibernation. When fish are plentiful they might just eat the head and brains and the roe, or fish eggs. When fish are scarce they will try to steal each other's catch.
Impact on Other Species The death of salmon feeds more than just the grizzly bears. The uneaten parts of the salmon carcases provide food for other animals, scavenger species and birds.
Pink and chum salmon runs along province's central coast haven't been doing so hot in recent years either, which raises questions about the long-term welfare of coastal grizzlies that feast on them. Government helicopter surveys conducted this fall along the Kimsquit River area north of Bella Coola, British Columbia, tallied below-average numbers of grizzly adults and cubs.
This suggests poor salmon returns of prior years might be taking their toll on the bears, starving them of their primary prehibernation food source. Coastal grizzlies are a different beast altogether from their smaller interior cousins.
Alaskan Grizzly Bears & Salmon Migration
The more salmon a male eats, the larger his skull grows; the more fish a female eats, the earlier she'll reach reproductive maturity—and the more cubs she'll have each year. The population density of grizzly bears in Alaska's salmon-rich areas runs 10 to 20 times higher than those in the sans-salmon interior of the state.
The more fish in an ecosystem, the more grizzly bears that can be supported. Remove the salmon from an ecosystem and grizzly numbers drop, which is what happened over the short term when Owikeno Lake's salmon stock went AWOL in coastal British Columbia in the late '90s.