Interpreting long-term fish landings records: environment and/or exploitation?

The California Department of Fish and Game data base of California commercial fish landings for the period 1928 to 1985 has been assembled in computer accessible form at the Pacific Fisheries Environmental Group in Monterey, California. Time series for fishes whose landings are known to vary during periods of ocean warming were compared to time series of sea surface temperature. Expected patterns of variation were confirmed in the seasonal cycle, but were less clear on the interannual scale. When interannual variation was considered, the most serious hindrance to interpretation of the landings series appeared to be the continued reduction of the fish stocks due to commercial exploitation; other factors are discussed. Landings data contain information potentially useful in climatological studies, but problems should be anticipated in their use.

Influence of climate on environmental factors associated with long-term changes in chlorophyll production for the Sacramento-San Joaquin delta and Suisun Bay, California

Long-term changes in chlorophyll production were predicted from environmental variables for the Sacramento and San Joaquin rivers and Suisun Bay using Box-Jenkins transfer function models. Data used for the analyses were collected semimonthly or monthly between 1971 and 1987. Transfer function models developed to describe changes in chlorophyll production over time as a function of environmental variables were characterized by lagged responses and described between 39 and 51 percent of the data variation. Significant correlations between environmental variables and the California climate index (CA SLP) were used to develop a conceptual model of the link between regional climate and estuarine production.

Long-term and seasonal patterns in coastal temperature and salinity along the North American west coast

Numerous integrated time series have been assembled that suggest global temperature has been increasing steadily over the last century. ... However, superimposed on the long-term warming trends of these series are decadal-scale fluctuations, periods of slightly increasing and even decreasing temperature followed by rapid increases in temperature. ... In this pilot study, data for 1931-1990 from eight [western North America] coastal stations are examined to test the utility of a state-space statistical model (developed by Dr. Roy Mendelssohn, PFEG) in separating and describing seasonal patterns and long-term trends.

Volcanic activity and global change: probable short-term and possible long-term linkages

Article reviews annual to decadal climate response to volcanism; long-term climatic response to volcanism; and recent results from ocean drilling in the North Pacific.

Long-term changes in the equatorial Pacific trade winds [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Past work has shown that surface zonal equatorial wind stress, zonally integrated from one side of the Pacific to the other, is the key variable for estimating long-term El Niño behavior in the eastern Pacific. ... We used detrended COADS pressure in the eastern and western equatorial Pacific and post-1960 detrended Florida State University equatorial wind stress zonally averaged across the Pacific to verify this relationship.

Climate-related long-term faunal changes in a California rocky intertidal community [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): The effects of gradual climate change (ie, multi-decadal) on biological communities are not well understood for most natural systems, owing principally to the lack of quantitative observations in early studies. ... We resurveyed invertebrate species on an intertidal transect in central California, first established and surveyed in 1931, to assess shifts in community structure.

Long-term response of Torrey pine to coastal climate: precipitation, temperature, and fog

EXTRACT (SEE PDF FOR FULL ABSTRACT): Torrey pine (Pinus torreyana Parry ex Carr.) has one of the most limited geographical ranges and population size in the Pinus genus; it is present only on Santa Rosa Island and on the coast between San Diego and Del Mar, where our research was conducted. A 168-year chronology (1827-1994) was developed using 28 increment cores extracted from 15 living and 2 dead stranding trees at Torrey Pines State Reserve, San Diego, California. ... The spatial correlation with western North America winter and spring precipitation, as well as with published tree-ring chronologies, indicates a connection with the American Southwest. Global correlation maps with winter sea level pressure and sea surface temperature are consistent with the hypothesis that San Diego precipitation is affected by a southerly displaced North Pacific storm track and by warmer water farther south, both leading to higher transport of lower latitude moisture.

A study on the trend of sports fishery of Mafia Island (Tanzania) along the East African coast from 1961-1972

Mafia waters in the western Indian Ocean on the east coast of Africa is a natural attractive area for fishing. It has extensive coral beds which harbour good fish life and attracts sport fishery in the area. About 12 commercially important fishes listed are caught by sports fishermen. The data indicates that this area can become an attractive centre for sports fishery almost throughout the year with peak season from November to February. Long-term planning of the fishery is necessary. The conservation measures should be evolved and gan fishing, dynamiting or any other kind of distructive fishing should be prohibited. This area has natural potential to become a sports fishing centre in the future and a great attraction for tourists and anglers.