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Alaska Map. Alaska Geography Facts I. 663,268 sq miles, including territorial waters 21% of the area of the entire lower 48. Bounded by: Gulf of Alaska Bering Sea Chukchi Sea Beaufort Sea (Arctic Ocean). Alaska Geography Facts II. Width: West - East 808 miles
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Alaska Geography Facts I 663,268 sq miles, including territorial waters 21% of the area of the entire lower 48. Bounded by: Gulf of Alaska Bering Sea Chukchi Sea Beaufort Sea (Arctic Ocean)
Alaska Geography Facts II Width: West - East 808 miles Length: North - South 1,479 miles Controlled by Federal Gov’t: 65% total area Shoreline: 34,000 miles Two Time Zones: Alaskan Aleutian Population (2006) 670,053
Alaska Geography Facts III Coastline Alaska: 33,904 miles Coastline Lower 48: 54,729 miles Alaska has 62% total Tidal Coastline of US Area of Continental Shelf in Alaska is huge Most fish are caught near shore and on the continental shelf
Geology of Alaska I Two Major Tectonic Plates North American Plate & Pacific Plate Understanding Plate Interactions Important Transform Boundary - sliding along Divergent Boundary - mid ocean ridge Convergent Boundary - subduction zone
Geology of Alaska II North American Plate: NA Craton is the Core NA Craton Rock: North/East corner of Alaska Remainder of Alaska is accreted terrain, rocks from further south that have been sequentially transported to Alaska by Plate Tectonics. Many different terrains. Continental Shelf is part of the Continental Plate Kula Plate - Oceanic plate subducted under NA but a last fragment accreted to shallow Bering Sea shelf.
Plate Tectonics Oceanic versus Continental Plates Ocean Spreading Centers Mid-Oceanic Ridge Volcanic Activity - Black Smokers Seamounts Continental Plates Override Oceanic Plates Oceanic Plates dive into Subduction Zones
Alaska Marine Map Beaufort Sea Chukchi Sea Gulf of Alaska Bering Sea
Alaskan Marine Regions Southeast Alaska Inland Waters Gulf of Alaska Coast Western Gulf of Alaska Alaska Peninsula Bering Sea Yukon Kuskokwim Delta Aleutian Islands Seward Peninsula Norton Sound Chukchi Sea Beaufort Sea
Freshwater Alaska More than 3 million lakes in Alaska Marshland & Wetland Permafrost Account for 188,320 sq mi of territory Alaska has 12,000 rivers, many with salmon runs 51 Tidewater Glaciers Many Glaciers feed Rivers, Marshes and Lakes
Geology & Fishing What does this have to do with fishing? 1. Nutrients eroded from rock feed food web 2. Ocean spreading centers & nutrients 3. Volcanism from subducted plates & nutrients 4. Freshwater Habitat for anadromous fish 5. Seamounts bring huge diversity 6. Fish Predators live on land
Alaskan Climate Latitude: 51° 20’ North to 71° 50’ North Longitude: 130° West to 172° East Record High Temp: 100°F Fort Yukon Record Low Temp: -80°F Prospect Creek Sea Ice: Cook Inlet, Bering, Chukchi and Beaufort Seas.
Global Warming What will be the effects of Global Warming? 1.Warmer water species will migrate north 2.Colder water species will migrate north 3. Ocean currents will change 4. Potentially profound effects on species distribution and abundance
Regional Climate Change El Niño &La Niña: Short term climatic fluctuations 1997 El Niño 1. Weird milky algal bloom in Bering Sea visible from space. 2. Implicated in protist infestations of many commercial species.
Pacific Decadal Oscillation PDO is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years PDO provokes a faunal regime shift, where the animals found most abundantly change in cold to warm and warm to cold shifts. Cold - crab, shrimp, herring, capelin Warm - cod, pollock, salmon
Pacific Decadal Oscillation Cold Phase Warm Phase
PDO Index The PDO Index is calculated by spatially averaging monthly sea surface temperature of the Pacific Ocean north of 20°N. The global average anomaly is then subtracted to account for global warming. Only October to March values are used because year-to-year fluctuations are most apparent during the winter months.
Geology & Fisheries Nutrient Input (Limiting Minerals) 1. Deep-Water Upwelling 2. Loess - Wind Borne Dust 3. Volcanic Ash 4. Tidewater Glaciers 5. Suspended Riverine Sediments 6. Nutrients Released at Ice Edge Algae Require Mineral Micro-Nutrients
Temperature, Light and Nutrients Control Algal Blooms 1. Growth of some algal species limited by nutrient availability (eg. Silica & Iron . 2. With appropriate nutrients, temperature and light regulate bloom growth rates. 3. Long days in late spring can promote huge blooms. 4. Single cell algae are the base of marine food chains.
