scholarly journals BERM BREAKWATER FAILURE AT ST. PAUL HARBOR, ALASKA

1988 ◽  
Vol 1 (21) ◽  
pp. 209 ◽  
Author(s):  
Javier Weckmann ◽  
George M. Watts
Keyword(s):  
Bering Sea ◽  
High Tide ◽  
Breaking Waves ◽  
Commercial Fishing ◽  
Volcanic Origin ◽  
South Central ◽  
Fishing Vessels ◽  
Fur Seals ◽  
Pribilof Island ◽  
The City

St. Paul Island, Alaska, is located at 50°10'N latitude and 170°15'W longitude in the south central Bering Sea. It is the most northward and largest island of the Pribilof Island group. The area of the island is about 70 square miles (180 square kilometers), with the city and harbor of St. Paul located at a cove (Village Cove) on the southern coastline. The Pribilof Islands are of volcanic origin and are generally hilly with much of the coastline consisting of precipitous rocky cliffs. Moderate to strong winds are characteristic throughout the year, causing the island to be treeless. It is predominantly covered with grasses, sedges, and wild flowers. The Pribilofs are a natural haven for a variety of flora and fauna. More than a quarter of a million seabirds nest each year along the coastal cliffs. About two-thirds of the world's population of northern fur seals migrate annually to the Pribilofs for mating purposes. The Pribilof Island area of the Bering Sea is also one of the most abundant and richest seafood grounds in the world. Due to a recent moratorium, the harvest of fur seals in the Pribilofs has been discontinued. In order to maintain existing cultural and economic resources, the City of St. Paul has elected to construct a harbor facility at Village Cove to provide services to commercial fishing vessels operating in the central Bering Sea. The maximum natural water depth in the Village Cove area is 26 feet (7.9m) relative to mean lower low tide datum (MLLWO.0). Mean higher high tide level is 3.2 feet (lm) above MLLW, with extreme high tide during storm periods being estimated at between 5.0 and 6.0 feet (1.5 to 1.8m) above MLLW. Waves approaching from the southwest sector have the most effect on St. Paul Harbor. During the winter months, breaking waves with heights of 25 feet (7.6m) and 13-16s periods can be expected at Village Cove several times each year.

Using acoustic data from fishing vessels to estimate walleye pollock (Theragra chalcogramma) abundance in the eastern Bering Sea

2011 ◽  
Vol 68 (7) ◽  
pp. 1231-1242 ◽  
Author(s):  
Taina Honkalehto ◽  
Patrick H. Ressler ◽  
Richard H. Towler ◽  
Christopher D. Wilson
Keyword(s):  
Bering Sea ◽  
Low Cost ◽  
Walleye Pollock ◽  
Theragra Chalcogramma ◽  
Accurate Information ◽  
Commercial Fishing ◽  
Acoustic Data ◽  
Eastern Bering Sea ◽  
Fishing Vessels ◽  
Walleye Pollock Theragra Chalcogramma

Eastern Bering Sea walleye pollock ( Theragra chalcogramma ) support one of the world’s largest fisheries. Because of walleye pollock’s high recruitment variability and relatively short life span, timely and accurate abundance indices are needed for fisheries management. Walleye pollock are surveyed biennially with an acoustic-trawl (AT) survey and annually with a bottom trawl (BT) survey. The latter tracks the demersal portion of the population using chartered fishing vessels, whereas the AT survey tracks the younger, midwater portion using research vessels and is critical for evaluating prerecruit abundances. Acoustic data collected from commercial fishing vessels conducting the BT survey were analyzed to provide information on midwater walleye pollock abundance at relatively low cost. A retrospective analysis of AT survey data identified a suitable index area to track midwater walleye pollock abundance. The BT survey acoustic data in that area tracked the AT survey abundance and captured its broad spatial patterns. This study is unique because commercial vessel acoustic data were used to estimate a new annual abundance index whose performance can be evaluated by a biennial research vessel survey. The new index will benefit managers by providing more accurate information on near-term abundance trends when dedicated research ship time is not available.

The Food of Fur Seals in the Eastern Bering Sea

1957 ◽  
Vol 21 (2) ◽  
pp. 237 ◽  
Author(s):  
Ford Wilke ◽  
Karl W. Kenyon
Keyword(s):  
Bering Sea ◽  
Eastern Bering Sea ◽  
Fur Seals

scholarly journals Subsidence at the "Trébol" of Quito, Ecuador: an indicator for future disasters?

2015 ◽  
Vol 372 ◽  
pp. 151-155 ◽  
Author(s):  
T. Toulkeridis ◽  
D. Simón Baile ◽  
F. Rodríguez ◽  
R. Salazar Martínez ◽  
N. Arias Jiménez ◽  
...  
Keyword(s):  
The State ◽  
Capital City ◽  
Fear Of Recurrence ◽  
The South ◽  
Sewer System ◽  
State Of Emergency ◽  
High Importance ◽  
Traffic Jams ◽  
South Central ◽  
The City

Abstract. A sinkhole of great proportions was produced in one of the most trafficked zones of Quito. Constructed in the late sixties, this area is of high importance in solving the traffic jams of the capital city. The sinkhole called "El Trebol" started to be generated in the form of a crater, reached finally dimensions of approximately 120 m in diameter and some 40 m of depth, where at its base the river Machangara appeared. The generation of this sinkhole paralyzed the traffic of the south-central part of the city for the following weeks and therefore the state of emergency was declared. Soon the cause of the sinkhole was encountered being the result of the lack of monitoring of the older subterranean sewer system where for a length of some 20 m the concrete tunnel that canalized the flow of the river collapsed generating the disaster. The collapse of this tunnel resulted from the presence of a high amount of trash floating through the tunnel and scratching its top part until the concrete was worn away leaving behind the sinkhole and the fear of recurrence in populated areas. The financial aspects of direct and indirect damage are emphasized.

Feeding habits and trophic level of the smooth hammerhead shark, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), off Ecuador

2018 ◽  
Vol 99 (3) ◽  
pp. 673-680 ◽  
Author(s):  
Colombo Estupiñán-Montaño ◽  
Luis Cedeño-Figueroa ◽  
José F. Estupiñán-Ortiz ◽  
Felipe Galván-Magaña ◽  
Alejandro Sandoval-Londoño ◽  
...  
Keyword(s):  
Trophic Level ◽  
Feeding Habits ◽  
Trophic Niche ◽  
Commercial Fishing ◽  
Dosidicus Gigas ◽  
Apex Predators ◽  
Marine Food Webs ◽  
Fishing Vessels ◽  
Marine Food ◽  
Index Of Relative Importance

As apex predators, sharks are known to play an important role in marine food webs. Detailed information on their diet and trophic level is however needed to make clear inferences about their role in the ecosystem. A total of 335 stomachs of smooth hammerhead sharks, Sphyrna zygaena, were obtained from commercial fishing vessels operating in the Ecuadorian Pacific between January and December 2004. A total of 53 prey items were found in the stomachs. According to the Index of Relative Importance (%IRI), cephalopods were the main prey (Dosidicus gigas, Sthenoteuthis oualaniensis, Ancistrocheirus lesueurii and Lolliguncula [Loliolopsis] diomedeae). Sphyrna zygaena was thus confirmed to be a teutophagous species. The estimated trophic level of S. zygaena was between 4.6 and 5.1 (mean ± SD: 4.7 ± 0.16; males: 4.7; females: 4.8). Levin's index (BA) was low (overall: 0.07; males: 0.08; females: 0.09), indicating a narrow trophic niche. We found that sharks <150 cm in total length consumed prey of coastal origin, whereas sharks ≥150 cm foraged in oceanic waters and near the continental shelf. The analyses indicate that S. zygaena is a specialized predator consuming mainly squids.

Late-glacial flow patterns, deglaciation, and postglacial emergence of south-central Baffin Island and the north-central coast of Hudson Strait, eastern Canadian Arctic

1996 ◽  
Vol 33 (11) ◽  
pp. 1499-1510 ◽  
Author(s):  
William F. Manley
Keyword(s):  
High Tide ◽  
Ice Sheet ◽  
Late Glacial ◽  
Flow Patterns ◽  
Sediment Provenance ◽  
Radiocarbon Dates ◽  
Ice Cap ◽  
The North ◽  
South Central ◽  
Ice Stream

New georaorphic, sedimentologic, and chronologic data are used to reconstruct late Quaternary ice-sheet flow patterns, deglaciation, and isostatic uplift along the largest marine trough connecting the Laurentide Ice Sheet with the North Atlantic Ocean. The Lake Harbour region was targeted for study given its potential to record flow from several ice-dispersal centers. Striations and sediment provenance indicators define flow patterns. Thirty-four radiocarbon dates constrain a chronology of events. Centuries or millennia(?) before deglaciation, a southeast-flowing ice stream impinged on southernmost Big Island, as recorded by a single striation site and delimited in extent by geomorphic evidence of cold-based ice. During the Cockburn Substagc (9000–8000 BP), the region was scoured by southward to southwestward flow from an ice cap on Meta Incognita Peninsula, as recorded by 60 striation sites along 200 km of coastline. Carbonate erratics are uncommon in till above the marine limit. Where present, they suggest that southward flow reworked older drift. At about 8200 BP, the area was dcglaciated, and the marine limit was established at elevations of 67–141 m above high tide. Iceberg calving and sediment discharge from an ice margin in Ungava Bay, Hudson Bay, or Foxe Basin then blanketed the area with limestone-rich glaciomarinc sediment. Afterward, the region experienced slow but sustained emergence. The data revise the maximum lateral extent of a Late Wisconsinan ice stream in Hudson Strait and emphasize the extent of a late-glacial ice cap on western Meta Incognita Peninsula.

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