ISSN:0363-2415    

DOI:10.1577/1548-8446-24-1

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A principal component analysis reveals that Pacific salmon catches in Alaska have varied inversely with catches from the U.S. West Coast during the past 70 years. If variations in catch reflect variations in salmon production, then results of our analysis suggest that the spatial and temporal characteristics of this “inverse” catch/production pattern are related to climate forcing associated with the Pacific Decadal Oscillation, a recurring pattern of pan-Pacific atmosphere-ocean variability. Temporally, both the physical and biological variability are best characterized as alternating 20-to 30-year-long regimes punctuated by abrupt reversals. From 1977 to the early 1990s, ocean conditions have generally favored Alaska stocks and disfavored West Coast stocks. Unfavorable ocean conditions are likely confounding recent management efforts focused on increasing West Coast Pacific salmon production. Recovery of at-risk (threatened and endangered) stocks may await the next reversal of the Pacific Decadal Oscillation. Managers should continue to limit harvests, improve hatchery practices, and restore freshwater and estuarine habitats to protect these populations during periods of poor ocean productivity.

ISSN:0363-2415    

DOI:10.1577/1548-8446(1999)024<0006:IPR>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

In 1978 biologists in Gainesville, Florida, began compiling records on the distribution and status of nonindigenous fishes known in U.S. inland waters. The database, now in electronic format, currently contains approximately 17,000 records representing more than 500 nonindigenous fish taxa (i.e., species, hybrids, and unidentified forms). Of these taxa, 317 (61%) are native to the United States but have been introduced by humans into U.S. drainages outside their natural geographic ranges; 185 (35%) are fishes introduced from foreign countries; and 22 (4%) are hybrids. Of the introduced foreign fish taxa, 71 (38%) are species that have established (i.e., reproducing) or possibly established populations in open U.S. waters. The database is a useful tool for natural resource managers and other decision makers. Although we periodically revise records and constantly enter new ones, our database is fairly updated; thus, we are able to more thoroughly analyze patterns of introduction and the spread of nonindigenous fishes within the United States. Moreover, information gaps exposed by the data set should serve to stimulate and guide future research on nonindigenous fishes. This paper introduces our database and provides an overview of temporal and spatial patterns of nonindigenous fish distributions in U.S. inland waters.

ISSN:0363-2415    

DOI:10.1577/1548-8446(1999)024<0016:SATPON>2.0.CO;2

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor