Analysis of soils and sediments for organic pollutants

20 samples of soil or sediment (7 of which were predominantly sand) from various locations were received for analysis of their content of organic pollutants. These analyses were performed using a capillary column gas chromatograph equipped with an electron impact (E.I.) mass spectrometer as detector and using computerised data storage. In addition to the target compounds, the full scan data were examined to determine the composition of natural organic products and a series of diagnostic fragment ions was used to search for additional anthropogenic products. Organic-rich environmental samples are notoriously difficult to analyse for pollutant organics owing to the presence of high concentrations of many natural organic compounds. A single procedure for extraction and clean-up was adopted. It was designed for chlorinated aliphatic and aromatic hydrocarbons and other pesticides containing acidic functional groups and was based on published methods for the determination of organic pollutants in soils and sediments. 4 soils and 2 sands showed levels of one or two groups of PCBs slightly in excess of the detection limit, one sample showed a similar level of 2,4-D and 3 samples contained dieldrin at or just above the detection limit.

Fish tracking technology development. Phase 1 project definition desk study

The document reports on Phase 1 of a definition study to appraise the options to develop fish tracking equipment, in particular tags and data logging systems in order to improve the efficiency of the Environment Agency's tracking studies and to obtain a greater understanding of fish biology. Covered in this report are radio telemetry, audio telemetry, High Resolution Position Fixing, data storage and archival tags and other fish tracking systems such as biosonics.

Diurnal and nocturnal temperatures for Atlantic salmon postsmolts (Salmo salar L.) during their early marine life

Data storage tags (DSTs) were applied to Atlantic salmon (Salmo salar L.) smolts during their seaward migration in the spring of 2002 at a fish counting fence on Campbellton River, Newfoundland. Our objectives were to discover whether or not salmon smolts could carry DSTs and survive, whether or not useful data on thermal habitat could be obtained and interpreted, and whether or not salmon smolts moved vertically in the water column. Data were downloaded from 15 of the recovered tags and revealed the hourly water temperatures experienced by the fish for periods of 3 to 71 days. The data on the DSTs were analyzed for temperature patterns in relation to migration behavior and diurnal movement of the fish. While in the sea, the DSTs recorded night temperatures of 12.5°C, which were higher than day temperatures of 11.6°C; the record from moored recorders, however, indicated that sea temperatures actually declined at night. It is hypothesized that posts-molts avoid avian predators during daylight hours by positioning themselves deeper in the water column and that they were pursuing prey during the deeper vertical descents or ascents noted during the periods of more rapid changes in temperature.

Movements, behavior, and habitat selection of bigeye tuna (Thunnus obesus) in the eastern equatorial Pacific, ascertained through archival tags

Ninety-six bigeye tuna (88– 134 cm fork length) were caught and released with implanted archival (electronic data storage) tags near fish-aggregating devices (FADs) in the equatorial eastern Pacific Ocean (EPO) during April 2000. Twenty-nine fish were recaptured, and the data from twenty-seven tags were successfully downloaded and processed. Time at liberty ranged from 8 to 446 days, and data for 23 fish at liberty for 30 days or more are presented. The accuracy in geolocation estimates, derived from the light level data, is about 2 degrees in latitude and 0.5 degrees in longitude in this region. The movement paths derived from the filtered geolocation estimates indicated that none of the fish traveled west of 110°W during the period between release and recapture. The null hypothesis that the movement path is random was rejected in 17 of the 22 statistical tests of the observed movement paths. The estimated mean velocity was 117 km/d. The fish exhibited occasional deep-diving behavior, and some dives exceeded 1000 m where temperatures were less than 3°C. Evaluations of timed depth records, resulted in the discrimination of three distinct behaviors: 54.3% of all days were classified as unassociated (with a floating object) type-1 behavior, 27.7% as unassociated type-2 behavior, and 18.7% as behavior associated with a floating object. The mean residence time at floating objects was 3.1 d. Data sets separated into day and night were used to evaluate diel differences in behavior and habitat selection. When the fish were exhibiting unassociated type-1 behavior (diel vertical migrations), they were mostly at depths of less than 50 m (within the mixed layer) throughout the night, and during the day between 200 and 300 m and 13° and 14°C. They shifted their average depths in conjunction with dawn and dusk events, presumably tracking the deep-scattering layer as a foraging strategy. There were also observed changes in the average nighttime depth distributions of the fish in relation to moon phase.

Climatological data in Mexico [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): This is a previous presentation of what has been observed in points spread in Mexico. The existing data amount is large enough that an atlas was given out in 1977. This atlas has information which goes back to the beginning of the country. The original data sets from which this atlas was issued exist in a variety of storage forms ranging from simple paper blocks up to books and magnetic tapes.

Frozen storage characteristics of cultured Macrobrachium rosenbergii (de Man)

Cultured Macrobrachium rosenbergii (Scampi, about 30 g each) in headless shell-on form was individually quick frozen in a spiral freezer. The frozen samples were glazed and packed in polythene bags, which were further packed in master carton and stored at -18°C. Samples were drawn at regular intervals and subjected to biochemical, bacteriological and organoleptic analysis to study its storage characteristics. The data on the above parameters showed that the samples were in prime acceptable condition when stored up to 23 weeks. No appreciable change in colour and odour was noticed in the raw muscle. Afterwards, organoleptic evaluation of the cooked muscle revealed slight change in the flavour. Texture also appeared little tougher. These changes in organoleptic characters were well supported by the biochemical bacteriological changes in the muscle.