Annual migrations,diving behavior,and thermal biology of Atlantic bluefin tuna, <Emphasis Type="Italic">Thunnus thynnus</Emphasis>, on their Gulf of Mexico breeding grounds

Electronic tags were used to examine the biology of Atlantic bluefin tuna (Thunnus thynnus L.) on their breeding grounds in the Gulf of Mexico (GOM). The hypothesis that movement patterns, diving behavior, and thermal biology change during different stages of the breeding migration was tested. Mature Atlantic bluefin tuna tagged in the western Atlantic and the GOM, were on their breeding grounds from February to June for an average of 39 ± 11 days. The bluefin tuna experienced significantly warmer mean sea surface temperatures (SSTs) within the GOM (26.4 ± 1.6°C) than outside the GOM (20.2 ± 1.9°C). As the bluefin tuna entered and exited the GOM, the fish dove to daily maximum depths of 568 ± 50 and 580 ± 144 m, respectively, and exhibited directed movement paths to and from the localized breeding areas. During the putative breeding phase, the bluefin tuna had significantly shallower daily maximum depths (203 ± 76 m), and exhibited shallow oscillatory dives during the night. The movement paths of the bluefin tuna during the breeding phase were significantly more residential and sinuous. The heat transfer coefficients (K) were calculated for a bluefin tuna in the GOM using the recorded ambient and body temperatures. The K for this fish increased rapidly at the high ambient temperatures encountered in the GOM, and was significantly higher at night in the breeding phase when the fish was exhibiting shallow oscillatory dives. This suggests that the fish were behaviorally and physiologically thermoregulating in the Gulf of Mexico. This study demonstrates that the movement patterns, diving behavior, and thermal biology of Atlantic bluefin tuna change significantly at different stages of the breeding migration and can be used to define spawning location and timing. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Effects of arsenic on survival and metabolism of Crangon crangon

Metabolic changes and toxic effects in Crangon crangon (collected during summer 1989 near Helsingør, Denmark and at Kulhuse in the Isefjord) were observed during exposure to different arsenate concentrations. Survival, respiration, and concentrations of hemolymph glucose, muscle glycogen andadenine nucleotides were measured. C. crangon was very tolerant of arsenate; survival was only affected at arsenate concentrations >25 ppm. Small individuals (0.2 to 0.29 g wet weight) were less tolerant than medium-sized and large individuals (0.5 to 0.59 g and 0.8 to 0.89 g wet weight), e.g. at 50 ppm the LT₅₀ for small individuals was 180 h compared to 343 h and 360 h in middle-sized and large individuals. The relation between size and toxicity is probably due to the change in surface/volume ratio. Under clean conditions the respiration of C. crangon showed a clear relation between routine MO₂ (O₂ in mlg^-1 h^-1) and wet weight (r²=0.89; P<0.001). During shortterm exposure to arsenate (10 and 50 ppm), the respiratory rates (MO₂) seemed to decrease in a size-dependent manner. The concentrations of blood glucose and muscle glycogen did not change in response to arsenate exposure. The concentrations of adenylate phosphates were high and constant throughout the experiments. C. crangon had maximal adenylate energy charge (AEC) values of ca. 0.8. No decrease in AEC due to the exposure to arsenate was observed.     

Verteilung chemischer Elemente in der Nahrung und Milch stillender Mütter

Goal and Scope

The transfer of various chemical elements from maternal food into human milk was investigated. Transfer factors (hereafter TF) food/mother’s milk were taken to represent those nuclides pertinent to radiation protection in order to estimate possible radioactive burdens of breast-fed babies.

Methods

A total of 23 mothers, mainly from the Euroregion Neisse (PL, CZ, D; all being in their mature phases of lactation), took part in this study (1998–2001), for time periods between two to eight weeks (8805 samples were analyzed). The diurnal uptake of elements was determined by the duplicate method.

Results and Conclusions

TF values determined for Ag, Au, Ba, Cd, Ce, Co, Cr, Cs, Cu, Fe, Ga, I, La, Mn, Mo, Nb, Ni, P, Pb, Ra, Rb, Re, Ru, Sb, Sr, Te, Th, Ti, U_o, Y, Zn, Zr were theoretically analyzed with the following result: metal ions transfer into mother’s milk mainly in coordinated states (i.e. bound to anionic ligands), with TF values which increase according to complex stabilities. Therefore it can be assessed that neither Cd nor Ba, both forming only weak complexes, pose hazards to breastfed children.

Outlook

There are relationships between transfer factors pertaining to certain elements and the amounts of others consumed by the mother; i.e. (changes in) consumption of one element influence the transfer towards women’s milk of another element. Accordingly, strategies can be developed to keep off hazardous substances — including fissiogenic radionuclides — from milk which is far more efficient than traditional isotopic dilution; however, iodide tablets are useful here, too.     

Preparation of high resolution chromosomes from amniotic fluid cells

A relatively simple method of obtaining high resolution chromosomes from amniotic fluid cells is described. The elongated chromosomes are achieved by adding ethidium bromide (5μg/ml) to the culture 4 1/2 hours before harvesting and the high resolution banding can be produced by usual banding procedures.     

Microbial Contamination of Groundwater at Small Community Water Supplies in Finland

The raw water quality and associations between the factors considered as threats to water safety were studied in 20 groundwater supplies in central Finland in 2002-2004. Faecal contaminations indicated by the appearance of Escherichia coli or intestinal enterococci were present in five small community water supplies, all these managed by local water cooperatives. Elevated concentrations of nutrients in raw water were linked with the presence of faecal bacteria. The presence of on-site technical hazards to water safety, such as inadequate well construction and maintenance enabling surface water to enter into the well and the insufficient depth of protective soil layers above the groundwater table, showed the vulnerability of the quality of groundwater used for drinking purposes. To minimize the risk of waterborne illnesses, the vulnerable water supplies need to be identified and appropriate prevention measures such as disinfection should be applied.     

Effect of metal accumulation on metallothionein level and condition of the periwinkle Littorina littorea along the Scheldt estuary (the Netherlands)

Metal (i.e. Ag, As, Ca, Cd, Co, Cu, Mn, Pb and Zn) and metallothionein (MT) concentrations in the soft tissue of Littorina littorea were measured along the heavily polluted Western Scheldt (WS) and relatively clean Eastern Scheldt (ES) estuary. Along the WS metal and MT levels in periwinkles reflected the known downstream decreasing pollution gradient. Surprisingly in ES animals As, Mn and Zn concentrations decreased from east to west reflecting past pollution. Compared to the WS metal concentrations of ES periwinkles were significantly lower and both estuaries were maximally discriminated from each other based on their Cd soft tissue concentration using a canonical discriminant analysis. Furthermore, no overall difference was found in MT levels among animals from both estuaries. Using previously obtained condition data (i.e. dry/wet weight ratio and lipid content) the relation between soft tissue metal concentration (i.e. Cd, Cu and Zn) and fitness indicators (i.e. MT and condition data) was examined using a canonical correlation analysis. Periwinkles with a high metal load (i.e. Cd and Zn) also had high MT levels but were in a relatively poor condition.     

Indoor/ambient residential air toxics results in rural western Montana

Indoor and ambient concentrations of 21 volatile organic compounds (including 14 hazardous air pollutants) were measured in the homes of nearly 80 western Montana (Missoula) high school students as part of the 'Air Toxics Under the Big Sky' program during the 2004/2005 and 2005/2006 school years. Target analytes were measured using low flow air sampling pumps and sorbent tubes, with analysis of the exposed samples by thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS). The results reported here present the findings of the first indoor/ambient air toxics monitoring program conducted in a semi-rural valley location located in the Northern Rocky Mountain/Western Montana region. Of all of the air toxics quantified in this study, toluene was found to be the most abundant compound in both the indoor and ambient environments during each of the two school years. Indoor log-transformed mean concentrations were found to be higher when compared with ambient log-transformed mean concentrations at P < 0.001 for the majority of the compounds, supporting the results of previous studies conducted in urban areas. For the air toxics consistently measured throughout this program, concentrations were approximately six times higher inside the student's homes compared to those simultaneously measured directly outside their homes. For the majority of the compounds, there were no significant correlations between indoor and ambient concentrations.