Strong, low frequency (decadal) environmental fluctuations during the 20th century in the North Pacific Ocean, on the Washington coast, and in Puget Sound

At decadal period (10-20 years), dynamic linkage was evident between atmospheric low pressure systems over the North Pacific Ocean and circulation in a Pacific Northwest fjord (Puget Sound). As the Aleutian low pressure center shifts, storms arriving from the North Pacific Ocean deposit varying amounts of precipitation in the mountains draining into the estuarine system; in turn, the fluctuating addition of fresh water changes the density distribution near the fjord basin entrance sill, thereby constraining the fjord's vertical velocity structure. This linkage was examined using time series of 21 environmental parameters from 1899 to 1987. Covariation in the time series was evident because of the strong decadal cycles compared with long-term averages, interannual variability, and seasonal cycles.

Reconstructing 20th century flood patterns in Havasu Creek, Arizona, using historical and dendrochronologic data [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Havasu Creek is the second largest tributary of the Colorado River in Grant Canyon. Perennial streamflow in the creek seldom exceeds 2 cubic meters per second, but it supports an important riparian habitat as well as unique travertine pools and waterfalls that attract over 20,000 tourists annually. Havasu Canyon is also home to over 400 members of the Havasu Tribe. Despite a long history of habitation and recreation in Havasu Canyon, streamflow records for Havasu Creek are extremely limited, making flood prediction difficult.

Integrating varve and tree-ring time series for southern California climate reconstruction: a 20th century outlook [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Our objective is to combine terrestrial and oceanic records for reconstructing West Coast climate. Tree rings and marine laminated sediments provide high-resolution, accurately dated proxy data on the variability of climate and on the productivity of the ocean and have been used to reconstruct precipitation, temperature, sea level pressure, primary productivity, and other large-scale parameters. We present here the latest Santa Barbara basin varve chronology for the twentieth century as well as a newly developed tree-ring chronology for Torrey pine.

The top ten California floods of the 20th century

The purpose of this paper is to summarize the biggest northern California floods of the 20th century. Flooding in California can occur from different causes. At least three types of floods occur: 1. Winter general floods, which cover a large area. 2. Spring and early summer snowmelt floods unique to the higher-elevation central and southern Sierra Nevada, which occur about once in 10 years on the average. 3. Local floods from strong thunderstorms, with intense rain over a relatively small area. These originate in moist tropical or subtropical air and include the flash floods of the desert and other areas of southern California when remnants of eastern Pacific hurricanes get carried into the state.

Socio-economic conditions of the pond owners of Demra, Dhaka

On the basis of fish culture status 96 ponds of the study area were classified into 4 categories like wild stock (27%), extensive culture (24%), improved extensive culture (33%) and semi-intensive culture (16%). Percentage of small, medium and large ponds were 38, 44, and 18 respectively whereas education levels below SSC, below Bachelor and above were 43, 38 and 19 respectively and single owners belonged to 54% of the ponds. Per hectare yields of extensive, improved extensive and semi-intensive categories of culture were 1.3, 2.12 and 4.0 metric tons respectively and their net return were 46, 63 and 92 thousand taka respectively. Considering the problems of fish culture, multiple ownership was found to be the most important one.

Socio-economic conditions and challenges of Kyoga lakes fisheries

Over the period 2008 to 2010, NaFIRRI carried out a number of socio-economic studies on the Kyoga lakes to provide an update of the socio-economic conditions of the fisheries and also to address specific areas of fisheries socio-economic issues and development concerns. The data collection was conducted using Key informant interviews, questionnaire sample surveys, Focus Group Discussions, secondary data searches and field observations. The objective of this fact sheet is, therefore, to provide key information from these studies for use at national, district, community levels as well as by other interested stakeholders.

Food security and poverty alleviation under the National Special Programme for Food Security: a preliminary socio-economic assessment of Yamama Lake, Kebbi state, Nigeria

The World Food Summit in its meeting in Rome in 1999 estimated that 790 million people in the developing world do not have enough food to eat. This is more than the total populations of North America and Europe combined. Nigeria is one of the developing countries affected by hunger, deprivation and abject poverty by its citizenry inspite of its enormous natural and human resources. To reduce poverty and increase food supplies to the masses the Federal Government of Nigeria embarked on a programmed-tagged National Special Programme for Food Security (NSPFS) in the year 2002. The programme's broad objectives are to attain food security in the broadest sense and alleviate rural poverty in Nigeria. One of the areas of the programme's intervention is in the aquaculture and inland fisheries development because Nigeria imported 681mt of fish in 2003 with a total cost of about N50 million. The paper assesses the socio-economic conditions of one of the selected water bodies (Yamama Lake) with a view to introducing community-based fisheries management plan for the rational exploitation and management of the fishery and other aquatic resources of the water body thereby increasing fish supply and improving the living standard of the fisherfolk in the area. Data were collected using Participatory Rural Appraisal (PRA) tools and questionnaire administration

Feeding of Gammarus lacustris Sars under different conditions of habitation [Translation from: [Trophic relations of freshwater invertebrates.] (ed. G. G. Vinberg) pp.94-98. Leningrad, Zool.Inst.AN SSSR, 1980]

The amphipod Gammarus lacustris, a regular representative of lacustrine communities, often plays a significant role in the transformation of matter and energy. The object of the present work was to clarify the quantitative side of the feeding of the amphipod under different conditions of habitation. Experimental works on determination of the rate of consumption of food and its dependence on body-weight were carried out in the summer periods 1975-1978 on three water-bodies of the Krasnoyarsk region, of different conditions of habitation for the amphipods.

Physiological Determinants of Invasive Success Linking Distribution Patterns to Metabolic Physiology in Native and Invasive Blue Mussels (genus Mytilus)

In the early 20th century, a blue mussel species from the Mediterranean invaded the California coast and subsequently out-competed the native species south of Monterey Bay. Like other invasive species, Mytilus galloprovincialis has physiological traits that make it successful in habitats formerly occupied by the native M. trossulus, namely its adaptation to warm sea surface temperatures. This study looks at the current genotype distributions and enzymatic activities of field-acclimatized mussels within the hybrid zone where the species co-occur as well as mussels that have been acclimated for four weeks to different temperature and salinity conditions. In the field-acclimatized and laboratory-acclimated mussels, the native species exhibited significantly higher enzyme rates, which may reflect an evolutionary adaptation to compensate to low habitat temperatures. Indeed, the results of the laboratory acclimation indicate that these differences are genetically based. Whether an acclimation capacity exists may require even longer-term acclimation to different temperatures. Current findings suggest that the further spread of the invasive species is likely to be governed in large measure by the potentially counteracting effects of rising temperatures, which would favor the northerly spread of M. galloprovincialis, and increased winter precipitation, which would favor the persistence of M. trossulus. However, the success of M. galloprovincialis during acclimation to ‘dilute’ salinity (25 ppt) suggests that the invasive species can tolerate a greater salinity range than previously thought. Thus, further investigation is needed to build a comprehensive predictive model of the movement of M. galloprovincialis and the hybrid zone along the California coast.

Commercial Whaling, Especially for Gray Whales, Eschrichtius robustus, and Humpback Whales, Megaptera novaeangliae, at California and Baja California Shore Stations in the 19th Century (1854–1899)

Shore whaling along North America’s California and Baja California coasts during 1854–99 was ancillary to the offshore and alongshore American whale fishery, which had begun in the North Pacific in the early 1800’s and was flourishing by the 1840’s. From its inception at Monterey, Calif., in the mid 1850’s, the shore fishery, involving open boats deployed from land to catch and tow whales for processing, eventually spread from Monterey south to San Diego and Baja California and north to Crescent City near the California–Oregon border. It had declined to a relict industry by the 1880’s, although sporadic efforts continued into the early 20th century. The main target species were gray whales, Eschrichtius robustus, and humpback whales, Megaptera novaeangliae, with the valuable North Pacific right whale, Eubalaena japonica, also pursued opportunistically. Catch data are grossly incomplete for most stations; no logbooks were kept for these operations as they were for high-seas whaling voyages. Even when good information is available on catch levels, usually as number of whales landed or quantity of oil produced, it is rarely broken down by species. Therefore, we devised methods for extrapolation, interpolation, pro rationing, correction, and informed judgment to produce time series of catches. The resulting estimates of landings from 1854 to 1899 are 3,150 (SE = 112) gray whales and 1,637 (SE = 62) humpback whales. The numbers landed should be multiplied by 1.2 to account for hunting loss (i.e. whales harpooned or shot but not recovered and processed).

History of Whaling and Estimated Kill of Right Whales, Balaena glacialis, in the Northeastern United States, 1620–1924

This study, part of a broader investigation of the history of exploitation of right whales, Balaena glacialis, in the western North Atlantic, emphasizes U.S. shore whaling from Maine to Delaware (from lat. 45°N to 38°30'N) in the period 1620–1924. Our broader study of the entire catch history is intended to provide an empirical basis for assessing past distribution and abundance of this whale population. Shore whaling may have begun at Cape Cod, Mass., in the 1620’s or 1630’s; it was certainly underway there by 1668. Right whale catches in New England waters peaked before 1725, and shore whaling at Cape Cod, Martha’s Vineyard, and Nantucket continued to decline through the rest of the 18th century. Right whales continued to be taken opportunistically in Massachusetts, however, until the early 20th century. They were hunted in Narragansett Bay, R.I., as early as 1662, and desultory whaling continued in Rhode Island until at least 1828. Shore whaling in Connecticut may have begun in the middle 1600’s, continuing there until at least 1718. Long Island shore whaling spanned the period 1650–1924. From its Dutch origins in the 1630’s, a persistent shore whaling enterprise developed in Delaware Bay and along the New Jersey shore. Although this activity was most profi table in New Jersey in the early 1700’s, it continued there until at least the 1820’s. Whaling in all areas of the northeastern United States was seasonal, with most catches in the winter and spring. Historically, right whales appear to have been essentially absent from coastal waters south of Maine during the summer and autumn. Based on documented references to specific whale kills, about 750–950 right whales were taken between Maine and Delaware, from 1620 to 1924. Using production statistics in British customs records, the estimated total secured catch of right whales in New England, New York, and Pennsylvania between 1696 and 1734 was 3,839 whales based on oil and 2,049 based on baleen. After adjusting these totals for hunting loss (loss-rate correction factor = 1.2), we estimate that 4,607 (oil) or 2,459 (baleen) right whales were removed from the stock in this region during the 38-year period 1696–1734. A cumulative catch estimate of the stock’s size in 1724 is 1,100–1,200. Although recent evidence of occurrence and movements suggests that right whales continue to use their traditional migratory corridor along the U.S. east coast, the catch history indicates that this stock was much larger in the 1600’s and early 1700’s than it is today. Right whale hunting in the eastern United States ended by the early 1900’s, and the species has been protected throughout the North Atlantic since the mid 1930’s. Among the possible reasons for the relatively slow stock recovery are: the very small number of whales that survived the whaling era to become founders, a decline in environmental carrying capacity, and, especially in recent decades, mortality from ship strikes and entanglement in fishing gear.

Interactions between climatic variables controlling subalpine tree growth: implications for climatic history of the Sierra Nevada, California

EXTRACT (SEE PDF FOR FULL ABSTRACT): Tree-ring records from foxtail pine (Pinus balfouriana) and western juniper (Juniperus occidentalis) growing near tree line in the eastern Sierra Nevada, California, show strong correlations with summer temperature and winter precipitation. Response surfaces portraying tree growth as a function of summer temperature and winter precipitation indicate a strong interaction between these variables in controlling growth. ... Above average growth for both foxtail pine and western juniper from AD 1480 to 1570 can be interpreted as indicating an extended period of warm, moist conditions unequalled during the 20th century.

Socio-economic survey of fisher families, 1958-59

Fisher families had been investigated by the Department of Commerce and Industries in earlier economic surveys conducted in 1935, 1938 and 1939 (Das Gupta, 1937 a & b; 1944 a & b). These surveys were directed at the general economic conditions of the urban and rural sectors of the population and therefore did not provide much information in particular on the life of the fisherman or his environment. The Department of Fisheries in 1954 conducted a rapid enquiry into the living conditions of fishermen to obtain some data on their income, indebtedness and general social conditions, at the request of the Canadian Co-operative Consultant for incorporation in his report on the "Status and Possibilities of Co-operative Development of the Fisheries of Ceylon” (MacDonald, 1954). The present survey was undertaken to provide more definite socio-economic information on the fishermen of Ceylon, covering such aspects as income, expenditure, indebtedness and living conditions. The survey was started in June, 1958, but was interrupted by the unsettled conditions of the Island at the time, taking therefore a little over a year for completion. Some of the data collected was used as a basis for a report on the living conditions of fishermen, incorporated in the “Guide to the Fisheries of Ceylon", a hand book published by the Department of Fisheries (Anon. 1958).

The Sundarbans fishers coping in an overly stressed mangrove estuary

The fishing community of the Sundarbans are the human group most at home in the mud-slush-water-forest environment of this famous mangrove estuary. Their skills, knowledge, and technique have developed in response to a challenging environment. Yet, of the countless studies on the various aspects of this eco-region, there are exceedingly few that have studied the Sundarbans fisher in his/her ecological, historical and demographic context—as a key stakeholder in an environment under considerable stress. The present study seeks to reduce this lacuna a little. Its object is not merely to examine and analyse, but also to identify means, both tradition-based and innovative, which might contribute to protect the environment, improve economic conditions, and usher in people-based governance of resources.

Fishery resources: their exploitation, management and conservation in Africa

The beginning of the 20th century saw the discovery of Africa's vast natural resources. Not only did explorers "discover" lakes, rivers, forests and mountains but scientists and naturalists also "discovered what at that time were called new species of plants, fish and other animals. Thus scientific names were tagged to various species using the famed binomial nomenclature and immortalising the names of some of the people who first described those species. Africa of course abounds with thousands of different floral and faunal varieties and the early colonial scientists found the African environment lucrative fron the point of discovery of new species. This paper therefore attempts to descrihe the role science could only in the development and exploitation of one of Africa's renewable resources namely fisheries. This paper has attempted to expose the value of fish in human nutrition, provision of employment and uplifting of social and economic standards. The fishery resources of Africa are extensive and in the main not fully exploited. These resources like other natural resources are exhaustible although renewable. Efforts to exploit these resources must be encouraged but scientific planning and management of the resource is called for.