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.

Holocene history of the El Niño phenomenon as recorded in flood sediments of northern coastal Peru

EXTRACT (SEE PDF FOR FULL ABSTRACT): The Holocene history of flooding in northern coastal Peru is believed to be a proxy record for the El Niño phenomenon. A recently completed set of 30 radiocarbon dates on overbank flood deposits and a tsunami deposit from the Casma region (Figure 1 and Table 1) establishes a chronology for the largest events that have occurred during the last 3500 years. ... The data presented here indicate that events much larger than the one in 1982-1983 may occur with a frequency of about once every 1000 years.

A 139-year dendroclimatic cycle, cultural/environmental history, sunspots, and longer-term cycles

Higher resolution time-stratigraphic records suggest correlation of lower frequency paleoclimatic events with Milankovitch obliquity/precessional cycles and of higher frequency events with the evidently resonance-related Pettersson maximum tidal force (MTF) model. Subsequently published records, mainly pollen, seemingly confirm that atmospheric resonances may have modulated past climatic changes in phase with average MTF cycles of 1668, 1112, and 556 years, as calculated in anomalistic years from planetary movements by Stacey. Stacey accepts Pettersson's dating of AD 1433 (517 YBP) for the last major perihelian spring tide based solely on calculations of moon- and earth-orbital relations to the sun. Use of AD 1433 as an origin for the tidal resonance model seemingly continues to provide a best fit for the timing of cyclical patterns in the presented paleoclimate time series.

Life history and behaviour of Indian prawns

Studies on life history and behaviour of prawns form an essential background for the understanding of the disposition of their fisheries and for the formulation of effective methods of exploitation and measures of conservation.

Life history of prawns: a review of recent studies with special reference to Indian species

The paper contains a brief review of the studies on the life histories of Indian species of prawns chiefly belonging to the family Penaeidae. References to similar work carried out outside India are furnished where significant variations have been observed. The three main larval stages viz., Nauplius, Protozoea and Zoea (Mysis) and their important characteristics, including modes of locomotion, are described. The post-larval development of one species that has been studied in detail (Metapenaeus dobsoni) is indicated in outline. Some aspects of the bionomics of these prawns, especially breeding and migration, are also briefly dealt with in view of their relevance in their life cycle. An outline of the life histories of some Palaemonid prawns of both fresh water and marine habitats is added at the end and the need for well- planned investigations in regard to species of such economic value as Palaemon carcinus (Macrobrachium rosenbergii) is indicated.

A report of the Fisheries Catch Assessment Survey in the Ugandan waters of Lake Victoria for the February 2008 survey

Between July 2005 and February 2008, ten Catch Assessment Surveys (CASs) were conducted at 54 pre-selected fish landing sites in the Ugandan part of Lake Victoria comprising approximately 10% of all landing sites in each of the 11 districts sharing the lake. The CASs were conducted following regionally harmonised Standard Operating Procedures (SOPs). This report covers the CAS conducted in February 2008 and puts into context the trends generated by results of the previous surveys. The catch rates of Nile perch in gillnetting boats with motor/sail, reduced from 26.9 kg boat-1 day-1 in August 2007 to 22.8 kg boat-1 day-1 in February 2008. Whereas the catch rates of paddle Sesse boats remained more or less the same as in August 2007. The Nile perch catch rates of the long line fishery of the boats using motor/sail was similar, 35 and 36 kg boat-1 day-1 in August 2007 and February 2008 respectively but the catch rates of paddle Sesse boats using long lines showed some more increase from 19 to 22 kg boat (-1) day (-1). In the tilapia fishery, the catch rates of the parachute boats using gillnets showed further decrease in a row from 12.6 kg boat-1 day-1 in December 2006, 11.6 kg boat-1 day-1 in March 2007, 11.2 kg boat-1 day-1 in August 2007 and 10.0 kg boat-1 day-1 in February 2008. The overall impact of reduced catch rates in the predominant effort groups, e.g. gillnetting boats using motor/sail in the Nile perch fishery and Parachute boats using gillnets in the tilapia fishery overshadowed the increases in less dominant effort groups and resulted in the lowest monthly catch estimates recorded in the surveys conducted since 2005. Whereas there was a clear downward trend in the Nile perch catch rates of boats using gillnets, which corroborates with the information of declining stocks from the recent Acoustics surveys, the catch rates in the long line fishery remained stable and even somewhat increasing in the last four surveys. The factors that maintain high catches against reduction of fish biomass in the long line fishery and their effects on sustainability of the Nile perch fishery should be investigated further. The Mukene fishery, characterised by large fluctuations in the catch rates did not show much change in the last two surveys in August 2007 and February 2008 and the annual catch estimates showed an overall increase of 7% from 2005 to 2007. The Mukene fishery in the Ugandan waters of Lake Victoria remained a near shore fishery in which paddle Sesse boats using small seines or scoop nets were the dominant craft.

Final report of the Fisheries Catch Assessment Survey in the Ugandan waters of Lake Victoria for the May 2011 survey

This report presents findings of the CAS conducted in the Ugandan waters of Lake Victoria in May 2011. The results of the previous eleven CASs conducted under the IFMP of the LVFO programme in July, August, September and November 2005; in March, August and December 2006; in March and August 2007; in February and December 2008; and March 2010 are included to show the emerging trends. The report also presents annual catch estimates for the Ugandan part of the lake from 2005 to 2011. Through these CASs, information is building up to show the emerging picture of fish production in the Ugandan waters of the lake. Similar surveys are conducted in the Kenyan and Tanzanian parts of the lake, which provide the lake wide perspective of fisheries production but this time not simultaneously as under the LVFO effort due to different sources and timing of funding. These data can now be utilised together with other Resource and Socio-economic Monitoring survey data for a stock assessment of the lake to provide a firm basis for planning and management of the fisheries resources.

Bottom trawl codend mesh selectivity for Bagrus docmac (Forskahl) from Lake Victoria, with some remarks on the proposed trawl fishery

The methods of estimating codend selectivity for alternate hauls are briefly described and applied to Bagrus docmac (forskahl) data from Lake Victoria. Certain inconsistencies are noted and it is postulated that they may be due to differential escapement of larger Bagrus docmac through the trawl meshes when the different codends were fitted. The calculated 50% selection lengths yielded a fair regression on measured weigh give a fork length selection factor of 2.33, consistent with data from the smallest codend mesh size used. The implications of the findings are briefly discussed in relation to the proposed Haplochromis trawl fishery 1971.

The establishment of a commercial fishery for Haplochromis in the Uganda waters of Lake Victoria

Lake Victoria, straddling the Equator, is the second largest lake in the world, with a surface area of approximately 26,000 square miles (41,500 square kilometers) and a maximum depth of about 300 feet. Uganda possesses most of the north end of the lake which consists of a long, indented coastline and a chain of offshore islands on the edge of a 'continental shelf' separating relatively shallow sheltered inshore waters from the deeper open waters of the lake. At the present time the lake is harvested mainly by a native gill net fishery confined almost entirely to the shallow sheltered inshore waters. The annual production of all species from Uganda waters is in the region of 24,000 tons per annum, and Tilapia(Cichlidae)is commercially the most important genus. Haplochromis, a close relative of Tilapia, but generally much smaller, contributes only a small amount to this annual production; see Table 1, although they are probably the most abundant group of fish present in the lake. Through international aid programmes Uganda has been offered a canning plant and it is thought that Haplochromis is the most suitable type of fish to be utilized by such a plant. The Uganda Fisheries Department are conducting research into processing techniques and marketing and the East African Freshwater Fisheries Research Organization was asked to conduct a survey of the Haplochromis stocks of the lake with a view to estimating the ability or otherwise of these stocks to support a commercial canning industry.