40 resultados para AK22-1928


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Ambystoma mabeei, a small relatively uncommon salamander of the sub-genus Linguaelapsus, is limited in distribution to the coastal plain of North and South Carolina. First described in 1928, few specimens have been collected and details of its biology have remained essentially unknown. (PDF contains 3 pages)

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A decline in the abundance of blackback flounders, together with the withdrawal of vessels from this fishery, has resulted in a lowered catch in recent years compared to the peak period 1928 through 1931. Data obtained from U. S. Fish and Wildlife Service Hatchery catch records and from fishermen's log book records show a drop in abundance of 63 per cent from the early 1930's to the present in the Boothbay Harbor region and of 31 to 40 per cent in the area south of Cape Cod. Information on the early life history and distribution of young blackback flounders and the size and age composition and distribution of fish subject to the commercial and sport fisheries indicates that the young are the product of local spawning and that the sport and commercial fisheries draw on a resident stock of primarily adult fish.

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At her launch on 19 October 1882 in Wilmington, Del., the Albatross was the world’s first large deep-sea oceanographic and fisheries research vessel, and she would go on to have a distinguished 40-year career, ranging from the north Atlantic Ocean to the Gulf of Mexico, around Cape Horn in 1887–88, and into the North Pacific. By 1908, Deputy Fish Commissioner Hugh M. Smith reported that “The Albatross has contributed more to the knowledge of marine biology than has any other vessel.” And, of course, her career continued for another 13 years, being decommissioned in late 1921, serving later as a training vessel for nautical cadets, and disappearing from the records in Hamburg, Germany, in late 1928.

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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.

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Sri Lanka's interest in trawler fishing dates back to 1902 when a Colombo merchant attempted to operate a trawler off Sri Lanka's waters. The next attempt was made in 1907. These attempts did not proceed any further. Between 1920 and 1923 a very comprehensive survey of the littoral waters around the island was carried out. One of the principal aims of the survey was to investigate the possibility of trawler fishing in the seas around. Malpas (1926) and Pearson and Malpas (1926) reporting the results of the survey indicated that the Wadge and Pedro banks were the only areas available for commercial trawler operations and indicated that the fish resources in the two banks could be profitably exploited. Commercial exploitation of the Wadge bank commenced in 1928 and a fishery is now firmly established in the bank. The Marine Biologist and the Director of fisheries in their administration reports and Sivalingam and Medcof (1957) and the author (1965) have reported on the progress of the Wadge bank fishery. Some of the trends indicated by an analysis of the records of the commercial trawling operations are further discussed in this paper.

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The object of this series of papers has been given in Part 1 (see Additional informations for details) which deals with the first known commercial fishery on the Wadge Bank from 1928 to 1935. There is no recorded trawling on the Bank between 1936 and 1944. This paper deals with the changes in the total catch (i.e. all species combined) per hour of trawling in relation to the changes in fishing intensity from 1945, when the present trawling activities started, to 1960. The effect of trawling on individual categories or varieties will be presented later.

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Evolution of fisheries research and FIRRI The earliest approach to fisheries research in Uganda dates from the first fisheries survey of Lake Victoria by Michael Graham between 1927 and 1928 (Graham, 1929). Based on references to the rich fisheries that were reported to Graham, it appears that during the 18th Century, catch per net per night averaged 300 tilapia, a revelation that led Graham to conclude that Lake Victoria is a tilapia lake. The "tilapia" later came to be known as Tilapia esculenta and T variabilis (Oreochromis esculentus and O. variabilis) respectively.

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The first fishery survey of Lake Victoria was conducted between 1927 and 1928 (Graham 1929). Atthat time, the lake had a diverse fish fauna and the fishery was dominated by two endemic tilapiine cichlids; Oreochromis esculentus (Graham 1929) and O. variabilis (Boulenger 1906). There were a number of other species such as Protopterus aethiopicus Heckel 1851, Bagrus docmac (Forsk.) 1775, Clarias gariepinus (Burchell), Barbus species, mormyrids, Synodontis spp, Schilbe intermedius (Linn.) 1762 and Rastrineobola argentea Pellegrin, 1904 that were also abundant in the lake most of which made a significant contribution to the fishery (Graham 1929, Worthington 1929, 1932, Kudhongania & Cordone 1974). Haplochromine cichlids were represented by at least 300 species more than 99% of them endemic (Greenwood, 1974; Witte et al., 1992 a & b). The fishery of Lake Victoria was similar to that of lakes Kyoga and Nabugabo (Worthington 1929; Trewavas 1933; Greenwood 1965, 1966; Beadle 1962, 1981). There were also important fisheries on the inflowing rivers of Lake Victoria, the most important of which were Labeo victorianus and Barbus altianalis (Cadwallader 1965). The small sized species notably Rastrineobola argentea and haplochromines cichlids were not originally commercially exploited.

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The present paper gives a full description of the organization of Acanthococcus antarcticus Hooker et Harvey, a not well known member of the Rhodophyllidaceae as well as gives for the first time description of the male and tetrasporic plants. Detailed organization of the carpogonial branches, spermatia and tetraspores is also presented. Nineteen figures illustrate the text (material collected at Deseado port, Santa Cruz prov., Argentina). The following text is the content of the discussion. From the description it is possible to confirm the position of Acanthococcus in the Rhodophyllidaceac as was done by Kylin (Kylin 1960, p. 290 et seg.). It has many similarities in the development of the carpogenic branches and in the formation of spermatia as well in the production of the zonately divided tetrasporangia with the genera of the family whose reproduction is known; Cystoclonium purpureum (Hudson) Batters and Rhodopyllis bifada (Good. et Woodw.) Kützing (Kylin 1923); Calliblepharis jubata (Good. et Woodw.) Kützing (Kylín 1928) and Craspedocarpus erosus (Hook. et Harvey) Sehmitz (Kylin 1932). Apparently the distinguishing feature of Acanthococcus is the structure of the vegetative frond, with the abundant development of rhizoidal filaments in the medula, besides the characteristic appendages of the cystocarps. Harvey's figure (Harvey 1847, P. 181, Fig. 3) of the tranverse section of the plant shows the central portion composed of a dense small-celled medula limited by a region of large cells which is externally covered by a small-celled cortex. As we have seen the small-celled filaments are not restricted to the central portion, but extend into the large-celled portion and can reach the cortex. On the other hand, the eros section of Acanthococcus depicted by Kützing (Kützing 1867, T. 93, Fig. h, under Callophyllis antartica), apparently belongs to another plant, so different in the structure when one compares his figure with Harvey's and the ones in this paper. RESUMEN EN ESPAÑOL Este trabajo presenta una completa descripción de la organización de Acanthococcus antarcticus Hooker et Harvey, un miembro poco conocido de las Rodofilidáceas, así como presenta por primera vez descripciones de las plantas masculinas y de las tetraspóricas. También por primera vez es presentada la organización detallada de las ramas carpogoniales, de los espermecios y de las trásporas. Diecinueve figuras completan el texto (material coleccionado en Puerto Deseado, Prov. Santa Cruz, Argentina).