A quantitative analysis of the phytoplankton of the Gulf of Panama III. General ecological conditions and the phytoplankton dynamics at 8°45'N, 79°23'W from November 1954 to May 1957

Bi-weekly phytoplankton samples were collected at 0, 10, and 20 m and enumerated by the Utermöhl sedimentation technique; 14C productivity measurements at 10 m, oblique zooplankton tows, and routine hydrographic observations were also made. Northerly winds induce upwelling during December-April, followed by a rainy season; a slight resurgence in upwelling may occur during July and/or August. Annual variations in upwelling intensity and rainfall occur. During upwelling, the upper 50 m, about 30 per cent of the total volume of the Gulf of Panama, is replaced with water 5 to 10 C colder than the more stratified, turbid and nutrient impoverished watermass present during the rainy season. The mean annual runoff accompanying an average annual precipitation of 2731 mm is estimated to equal a layer of fresh water 3.2 m thick. About 10 per cent of the phytoplankton phosphate and inorganic nitrogen requirements during the rainy season are accreted. (PDF contains 260 pages.)

Influence of shelf-break fronts on shellfish and fish stocks off Argentina [Contribution to ICES Annual Science Conference, Reykjavik, Iceland, 27 Sep- 04 Oct 1996]

The general circulation pattern in the western boundary of the SW Atlantic is dominated by the opposite flows of Malvinas (-Falkland)and Brazil Current. In the Confluence region both currents separate from the continental slope and flow offshore creating an area of strong contracts and complex dynamics. The shelf-break fronts off Argentina mark the transition between shelf waters of mixed origin and nutrient rich Malvinas waters. Two areas deserve special attention due to the steep gradients introduced by the outflow of important sources of continental waters: the Rio de la Plata and the Magellan Strait to the north and south of the study area. Characteristics of the front is the high primary and secondary production, and the presence of important invertebrate and fish stocks that concentrate along the front to feed or spawn. The area comprises nearly 30 o/o (333 million U$S in 1995)of all Argentine catches of fish and squid. Resources in the area, beyond the EEZ limits, support international fisheries mainly of Russia, Poland and Spain. (Document contains 15 pages & figs)

Creation of temporary ponds for amphibians in northern and central Europe

More than 4000 ponds have been created or restored in Denmark since 1985 as part of a large-scale pond-digging programme to protect endangered amphibians in particular and pond flora and fauna in general. Most ponds are created on private land with public financing. The programme was triggered by, among other factors, a drastic decline in amphibian populations in Denmark between 1940 and 1980. However, in recent years there has been an increased awareness in Denmark that temporary ponds are important for the conservation of some of the most rare amphibian species, such as fire-bellied toad Bombina bombina, natterjack toad Bufo calamita and green toad Bufo viridis. Other rare species such as moor frog Rana arvalis and European tree frog Hyla arborea also benefit from temporary ponds. The last 15 years of work on the conservation of endangered species and their habitats has resulted in a last-minute rescue and a subsequent growth in the size of most Danish populations of fire-bellied toad and green toad; some populations of the relatively more common natterjack toad have also increased. The creation of temporary ponds plays an important role in the success of these three species. The creation of ponds to help restore viable populations of the most rare amphibians has not been easy. To study the conditions that may need to be created, Danish herpetologists searched for areas with temporary ponds that had good water quality, natural hydrological conditions and a management regime influenced by traditional agricultural methods. The paper gives an overview of pond creation and restoration projects in Denmark and Poland and their significance for amphibian diversity.

Evaluation of NRA tracking studies. Future projects and technical development

Fish tracking is a valuable technique for the provision of detailed information on the behaviour patterns of individual fish especially during estuarine and riverine migration. 2. Tracking studies help in the provision of a comprehensive description of the variety offish behaviour patterns in response to factors such as water flow, obstructions and water quality. 3. There are advantages to be gained by complementing fish tracking studies with data collected from fish counters and vice versa. 4. An overall evaluation of NRA fish tracking projects is presented in the wider context of NRA strategic research objectives. 5. The requirement for future development of tracking equipment, improved data analysis techniques, better communication and more immediate report preparation is identified. 6. Individual project evaluation is given for NRA (or the appropriate Water Authority predecessor) tracking studies conducted on the Ribble estuary, the River Tamar, River Torridge, Rivers Test and Itchen, River Lodden, the Welsh River Dee, River Glaslyn, River Taff, River Tawe, River Tywi, River Usk, Rivers Avon and Stour and the River Frome. 7. An outline for future strategic research is provided which identifies particular areas for study:- i) Identification of environmental factors which control the entry of fish into rivers. ii) Improvement of the understanding of the relationship between water flow and upstream movement of salmonids. iii) Examination of the detailed movements and behaviour of fish in relation to obstructions. iv) Closer definition of water quality requirements for salmonid fish. v) Definition of habitat preferences of salmonids in rivers. vi) Subsidiary topics such as the movements of non-salmonid fish and the downstream migration of kelts and juvenile salmonids.

Comparison of six tag types in sea-trout tagging experiments in the Baltic Sea

In the international Baltic Sea trout tagging experiment 27 753 hatchery reared sea trout smolts were tagged in Denmark, Finland, Poland and Sweden in 1979 and 1980. The fish were tagged with the original Carlin tag, two modified Carlin tag types (Canadian and Finnish polythene), streamer and Floy tags and Polish tags attached with Monel metal wire. The tag returns were affected by the place of release and smolt quality. The best results were obtained in the case of tags attached with double wire or thread -original Carlin, Canadian and Finnish polythene. The poorest results were obtained with streamer tags.

Value chain analysis: shrimp, prawn and tilapia from the southern region of Bangladesh & feasibility analysis: brackish water sea-bass in the southern region in Bangladesh

The WorldFish Center is implementing the FtF Aquaculture Project in 20 southern districts in Bangladesh. The project is implemented under USAID’s Feed the Future initiative in collaboration with the Government of Bangladesh. The project contributes to achieving the ‘Feed the Future’ goals through four objectives: (i) dissemination of improved quality fish and shrimp seed, (ii) improving the nutrition and income status of farm households, (iii) increasing investment, employment and fish production through commercial aquaculture and (iv) policy and regulatory reform and institutional capacity building to support sustainable aquaculture growth. The project commissioned this study to gather insights into the value chains of shrimp, prawn and tilapia in the project region and the feasibility of promoting culture of brackish water sea-bass in the region. The findings and recommendations are expected to provide the foundation for the project to design its interventions for achieving its goals.

Study of inter species diversity and population structure by molecular genetic method in Iranian Artemia

Artemia is a small crustacean that adapted to live in brine water and has been seen in different brine water sources in Iran. Considering the importance of genetic studies manifest inter population differences in species, to estimate genetic structure, detect difference at molecular level and separate different Artemia populations of Iran, also study of phylogenic relationships among them, samples of Artemia were collected from nine region: Urmia lake in West Azerbaijan, Shoor and Inche-Borun lakes in Golestan, Hoze-Soltan and Namak lakes in Qom, Maharloo and Bakhteghan lakes in Fars, Nough pool in Kerman and Mighan pool in Markazi and DNA extracted by phenol-chloroform method. Primers designed on a ribosomal fragment (16s rRNA) of mt DNA sequence and PCR was done. Digestion of the 1566 bp segment PCR product by 10 restriction endonuclease (Alu I, EcoR I, Eco47 I, Hae III, Hind III, Hinf I, Mbo I, Msp I, Rsa I, TaqI) showed 25 different haplotypes: 9 in Urmia, 4 in Shoor and Inche- Borun, 1 in Namak and Hoze-Soltan, 3 in Mighan, 1 in Bakhtegan Maharlo, 3 in Maharloo and 4 in Nough. Measurement of haplotype and nucleotide diversity intra population and nucleotide diversity and divergence inter populations and evolutionary distance between haplotypes showed a high diversity in mitochondrial genome of Artemia in studied regions whose results are similar to those explained for highly geographic expansion organism. In addition, results showed considerable heterogeneity between different populations and there are enough evidences in haplotypic level for separation of studied samples and division of Iranian Artemia to seven populations including Urmia, Shoor and Inche-Borun, Hoze-Soltan and Namak, Maharloo, Bakhteghan, Nough and Mighan. Phylogenetic analysis of the 16S rRNA data set resulted strict consensus and neighbor joining distance trees, demonstrated that all samples were monophyletic and parthenogenetic form derivation from bisexual populations and genetically high resemblance to those of A. urmiana. Study of 270 specimens from different region showed the genus Artemia in Iran clustered into three clades including: 1- Shoor, Inche-Burun, Hoze-Soltan, Namak, Bakhtegan and Maharloo 2- Nough and Mighan 3- Urmia. Totally, obtained results indicated to ability of used techniques for study of inter species diversity, population structure, reveal of phylogenic relationship and dividing of different populations of Artemia in Iran.