Video technology applied to the management of Bahrain's marine resources

Video technology has been used as a tool in research for many years. However, its widespread use as a fisheries management tool has been limited due to its relatively high cost. This is changing as video technology becomes a household commodity now widely available throughout the world.

A case study of the disappearance of Arius tenuispinis (marine catfish) in the vicinity of Visakhapatnam due to mechanised fishing

Visakhapatnam is on the eastern sea board of India (17 degree 40' N and 83 degree 15' E) having a continental shelf of 45 km width which is provided with a polychaete rich, silty clay sea floor to a distance of 15 km and beyond, from the shore. Repeated trawling by a large number of trawlers over an area of 900 sq.km (30 x 30) resulted in the hardening of the substratum to the extent of making it uninhabitable to the polychaetes and polychaete feeding fish. The shoaling and strictly demersal marine catfish, Arius tenuispinis, which is a prolific polychaete feeder on the fishing grounds off Visakhapatnam, has been on the decline since 1979. The catch rate of fish dropped from 9.7 kg/boat per day in 1979 to 2.6 kg by 1985-86. In the bottomset gillnets, the catch per net dwindled from 4.4 kg in 1973 to 0.04 kg by 1985-86. The species has virtually disappeared from the fishing grounds off Visakhapatnam and further north, as a results of the cumulative effect of overfishing with trawlnets and bottomset gillnets. It is further aggravated by the hardening of the sea floor on these grounds due to repeated trawling over a narrow zone.

On the naturalness of change in marine populations

Based on a talk given before a meeting of the Society of Fisheries Technologists, India.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 1. Preliminary report: introduction and description of the stations

The Austrian-Ceylonese hydrobiological mission of 1970 investigated and made collections from 36 flowing water systems (brooks, torrents, rivers); of these, 34 water systems were in the mountains regions of south-west and south-east of Sri Lanka. In the crystalline mountain region, the water systems are extremely poor in electrolytes, very soft and slightly acid; these torrential streams have strong falls, high flow velocities and boulder bottoms. The water temperatures increase from the sources and brooks at 2,000 m altitude to the mouths from 15°C to 28°C. The density of animal population (macro and meso-fauna) increases from the river bank regions (and pools) towards the sections with strong current and reaches on the rocks in the cascades a density of 500 to appr. 750 individuals/1/16m².

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 2. Hydrochemical studies on mountain rivers in Ceylon

The morphology, climate, geology and geochemistry of Sri Lanka is briefly described. The separation into a wet zone (the south-west and greater part of the central highland) and a dry zone with two very dry parts in the south-east and in the north-west, is obvious and has great influence on the hydrochemistry of the island. Geology is very homogenous (Precambrian crystalline series) and some Jurassic and Miocene limestones (only in the north).

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 3. Uber einige wassermilben aus Ceylon (Hydrachnellae, Acari)

In the study are described five species of watermites, collected by the Austrian-Ceylonese hydrobiological mission 1970 in torrents of the highlands of south-west Sri Lanka. The species are: Torrenticola (Monatractides) pusta Cook, 1967, T.(M.) Oxystoma hamata (Lundbald, 1941), T.(M.) ceylonensis nov. spec., Atractides schwoerbeli Lundbald, 1969 and Arrenurus (Micruracarus) madaraszi Daday, 1898.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 4. List of reptilia and amphibia collected in the mountains of south-west Ceylon, with notes on finding localities

Sri Lanka is a comparatively small island (65.584 km²) within the equatorial belt of calms. There are only slight seasonal variations in temperature, air humidity and day length. A description is given of the amphibian and reptile material brought back from the Austrian Indo-Pacific expedition, 1970-71. Some notes on the habitat of the animals are included.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 5. Decapoda Caridea

The first comprehensive study on the freshwater Caridea of Sri Lanka was by Arudpragrasm and Costa in 1961. Although it was the intention of these authors to continue this study no opportunity was available to them. The present faunal survey however has afforded the present writer to make a detailed study of the distribution of these shrimps especially in the mountain streams of the south-west of Sri Lanka. Two species and two sub-species of Caridina, one species of Atya and four species of Macrobrachium were collected by the hydrobiological mission from the hill streams of Sri Lanka.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 6. A new Drepanosticta from Ceylon (Order: Odonata; insecta)

The author describe a new species of Drepanosticta from Sri Lanka. This new species is named in honour of the collector, Professor Dr. F. Starmühlner.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 7. Dryopidae and Elminthidae of Ceylon

This report comprises a summary of parasitic copepods from fishes in Ceylon, as isolated from the branchial material of fishes belonging to previous collections. Seven copepod species are described in detail, as well as one species of Branchiura and one species of Isopoda. Caution is advocated to avoid further introductions via parasite-infested fishes, since only four of the above species are endemic.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 9. Dytiscidae (Coleoptera)

The intensive collecting of Prof. Dr. F. Starmühlner and Prof. Dr. H. H. Costa in Ceylon in 1970 produced among others some Dysticidae. The material turned out to be especially interesting as it comes all together from running waters, in which otherwise collecting is infrequent. From Sri Lanka quite a lot of species of Dytiscidae are already known.

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the 1st Zoological Institute of the University of Vienna (Austria) and the Department of Zoology of the Vidyalankara University of Ceylon, Kelaniya. Pt. 10. Freshwater triclads (Turbellaria, Tricladida) from Ceylon

The collection of Triclads from the Austrian-Ceylonese hydrobiological mission originates from 23 streams in the mountains of the south of Sri Lanka. All collected animals are of the Dugesia gonocephala (Dug.) type. Unfortunately the determinable mature animals were very rare in the samples but it seems certain that all the Triclads, found by the mission, belong to Dugesia nannophallus, described by Ball in 1970 after two individuals from Dunhinda, Badulla (Prov. Uva, Sri Lanka).