70 resultados para 157-955A


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The nitrification in the ocean is influenced by several environmental factors and the importance of these is more or less known. There are very likely many more to be discovered in the study of the interaction of nitrification bacteria and other micro-organisms in the ocean. Some of the factors to be considered will briefly be dealt with in this paper. Then the authors give the results of an incubation experiment in the Baltic Sea and from a detailed study in Gullmarn.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Fish were collected weekly in Biscayne Bay using a monofilament gill net set from a small skiff during 20-30 minute intervals. Although weekly sampling took place for 2.5 years, only the data from samples collected from June 1976 to June 1977 were used in this document. Abnormal external conditions of fins and body were observed on each fish and recorded. Fish were returned immediately to their habitats. Fish collected in the time period for this study numbered 3,765 and included 32 species. Of these, 16 species, totaling 3,556 fish, were caught in sufficient numbers (20 or more) to warrant data analysis. Only 3 of the 16 species could be considered relatively unafflicted: Aetobatus narinari (spotted eagle ray), Diodon hystrix (porcupinefish), and Selene vomer (lookdown). More than 80% of the examined specimens of these three species were unaffected. Less than 20% of the specimens of Diapterus plumieri (striped mojarra), Micropogonias undulatus (Atlantic croaker), and Pogonias cromis (black drum) displayed normal conditions. The three most afflicted species were Diapterus plumieri, striped mojarra; Micropogonias undulatus, Atlantic croaker; and Pogonias cromis, black drum. Only 7, 3, and 7% respectively showed no external evidence of disease. Data described in this document were originally tabulated in the mid-1970s, remained unpublished, and are no longer available. This document was based on archived unpublished text, a data summary table, and figures. Most of the text and cited references were the ones used in the original manuscript and no attempt was made to update them. (PDF contains 44 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Cephalopod remains (beaks, bodies, and parts of bodies) were collected from the stomachs of 157 sperm whales (Physeter macrocephalus) taken off central California (lat. 37°-39°N). At least 24 species representing 14 families were identified. Frequencies of occurrence of the six most numerous taxa were Moroteuthis robusta 72.0%, Gonatopsis borealis 66.2%, Histioteuthis dofleini 36.9%, Galiteuthis spp. (including G. phyllura and G. pacifica) 36.3%, Octopoteuthis deletron 35.0%, and Vampyroteuthis infernalis 27.4%. One find of two Mesonychoteuthis hamiltoni beaks strongly suggests transequatorial migration by one large male sperm whale. (PDF file contains 18 pages.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Die 24. Sitzung des Komitees für Fische und Fischerzeugnisse wurde vom 5. bis 9. Juni 2000 erstmalig in Ålesund, Norwegen, durchgeführt. Die Tagung wurde von 140 Delegierten und Beobachtern aus 43 Mitgliedsstaaten und 3 internationalen Organisationen (EU, A.C.P. Generalsekretariat und Internationale Vereinigung der Fischinspektoren, IAFI) sowie FAO- und WHO-Personal (4) besucht. Die größten Delegationen stellten Frankreich (6), Kanada (6), Thailand (7), USA (10), Marokko (13) und Norwegen als Gastgeber (16). Die deutsche Delegation wurde von Dr. Achim Viereck (BML) geleitet. Weitere Mitglieder waren Dr. Jörg Oehlenschläger (BFAFi, Sprecher), Dr. Reinhard Schubring (BFAFi), Dr. Günter Klein (BgVV) und Dr. Matthias Keller (Bundesverband der deutschen Fischindustrie und des Fischgroßhandels). Die Sitzung, die von Peter Gullestad, dem norwegischen Generaldirektor für Fischerei, eröffnet wurde, leitete Dr. Bjorn Rothe Knudtsen, Regionaldirektor des norwegischen Direktorats für Fischerei und Aquakultur, Trondheim.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A brief discussion is presented on the current situation regarding world fisheries and the future role of aquaculture. The various components involved in fisheries, and affecting all changes in fisheries through time, include the biology of the species involved, environment, technology/engineering and socio-economics. The importance of education in fisheries and aquaculture development is also examined

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An examination is made of the requirements for the commercial propagation of carp and tilapia in Nigeria. It is concluded that the operation of a successful Fish Hatchery and fry production system will depend on the following factors: 1) Correct initial planning for intended production (both species and intended numbers); 2) Design of the appropriate facilities to enable required production; 3) Selection of top calibre, dedicated and experienced hatchery staff; and, 4) The ethical responsibility taken by the hatchery management to produce only the highest quality seed under the best possible conditions. Purchasing farmers are dependent on this

Relevância:

10.00% 10.00%

Publicador:

Resumo:

On 31 Oecember 1992, the Institut für Seefischerei Hamburg (ISH) will dissolve its branch of systematic ichthyology at the Zoologieal Museum Hamburg University. Remaining ISH ichthyology staff and facilities will move back in January 1993 to Institut für Seefischerei headquarters in Palmaille 9, D-·2000 Hamburg 50 (Tel. 040·389050, Fax 040·38905 129). The research field systematic ichthyology will not be continued at ISH. The ISH fish collection will be handed over to the Zoological Museum of Hamburg University (ZMH) as future responsible holder from 1 January 1993 onward. Loan requests for former ISH material should be addressed from January 1993 on only to: Prof. Dr. H. Wilkens, Kustos Ichthyologie, Zoological Museum der Universität, Martin-Luther-King-Platz 3, D·2000 Hamburg 13 (Tel. 040·4123 3870, Fax 040·4123 3937). A couple of months will be needed before requests for loan of former ISH holdings can be handled again. It should, however, be noted that even for a longer period there may be problems in serving loan requests promptly due to logistic difficulties and shortage of staff at the ZMH ichthyology department.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The Azraq oasis lies in the Jordanian desert, about 85 km east of Amman. In this brief paper the author summarises his observations from a visit to the oasis in 1991, discusses the effects of pumping groundwater from the oasis to Amman and presents results from a plankton survey.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This brief paper discusses the assumption that watercourses might be harbouring a chemical(s) affecting the sexual development in fish. Male fish was found with the oestrogen-dependent blood protein, vitellogenin, usually found only in maturing females. The author examines a number of man-made chemicals present in the environment have been found to be oestrogenic. The paper concludes that rivers contain environmental oestrogens that are capable of causing disruptions in the sexual development of fish. Whether or not these environmental oestrogens are causing a widespread disruption in reproduction in wild fish, however, has yet to be determined.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Morphological observations of the dinoflagellate Ceratium hirundinella are given and a key to the difference in types provided. Illustrations are included.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The objective of this study is to describe the present statu s of the coarse fish populations of the River Avon, Hampshire. The study arose from a widespread concern among anglers and riparian owners that fish numbers had decreased since the early 1970's, and from a scarcity of accurate information on population densities on which to assess this complaint. It was realised at the outset that, without such information from earlier years, the survey would not reveal the extent of any decline in the fisheries. The result s of the survey are compared with available data from other rivers , chiefly the nearby R. Frome and R. Stour. They may be used to assess any futur e changes in population densities and growth rates, and to indicate promising areas for future research. The data were collected from a quantitative survey of twelve river sections along the fifty kilometres of river between Salisbury and Sopley, and a qualitative survey of three weir pools within the same area from 14 September to 9 October, 1987.

Relevância:

10.00% 10.00%

Publicador: