'Thinking like a fish': adaptive strategies for coping with vulnerability and variability emerging from a relational engagement with kob

Based on ethnographic fieldwork amongst a group of commercial handline fishers in the town of Stilbaai in South Africa's southern Cape region, this paper presents a range of flexible, adaptive and evolving strategies through which fishers negotiate constantly shifting variability in weather patterns, fish stocks, fisheries policies, and economic conditions. These variabilities constitute a diverse set of vulnerabilities to which fishers must respond in order to sustain their livelihoods. In this context, the act of 'thinking like a fish' on the part of the fishers provides them with an effective means of adapting to variability and uncertainty. Findings of ethnographic research in 2010-11 suggest that a number of the fishers who participated in the research actively work towards achieving a balance between profit and sustainability. 'Thinking like a fish' is an embodied, interactive way of knowing that emerges from interactions between fishers and fish, offering an ethical and ecological outlook which is a valuable resource for fisheries and conservation management in the region. We suggest that the deeply embodied interactional component of 'thinking like a fish' results from a desire to understand the life world of fish and to think from their perspective in order to more effectively target them while sustaining the species and ecosystem

Analiza proteinskih adukata kao biomarkera kratkotrajne izloženosti etilen oksidu i rezultati biomonitoringa

An accidental exposure of six workers to ethylene oxide (EO) provided the rationale for a biomonitoring and follow-up study, whose aim was to analyse protein adduct kinetics and examine the differentiation between accidental and environmental exposure, e.g., from tobacco smoke. For this purpose, the decrease in the concentration of the haemoglobin adduct N-2-hydroxyethylvaline (HEV) was followed during a fi ve-month period after the accident, together with N-2-cyanoethylvaline (CEV) and urinary cotinine, two well-established biomarkers for smoking. The follow-up study showed that EO adduct concentrations significantly increased after a short but presumably high exposure. Initial biomonitoring revealed HEV levels above 500 pmol g-1 globin in all cases, with a maximum of about 2,400 pmol g-1 globin. This compares to a German EKA value (exposure equivalent for carcinogenic substances) for a daily 8-h-exposure to 1 ppm EO of 90 μg L-1 blood (~3,900 pmol g-1 globin). The adduct levels dropped in accordance with the expected zero-order kinetics for a single exposure. After the five-month observation interval, the HEV concentrations in blood refl ected the individual background from tobacco smoking. The results of this study show that even a short exposure to ethylene oxide may result in a signifi cant rise in haemoglobin adduct levels. Although protein adducts and their occupational-medical assessment values are considered for long-term exposure surveillance, they can also be used for monitoring accidental exposures. In these cases, the calculation of daily ‘ppm-equivalents’ may provide a means for a comparison with the existing assessment values.U radu su prikazani rezultati biomonitoringa provedenog neposredno nakon akcidentalnog izlaganja šestorice radnika etilen oksidu i studije praćenja (follow up) provedene u cilju procjene kinetike razgradnje proteinskih adukata i utvrđivanja razlika nakon kratkotrajne izloženosti i izlaganja čimbenicima iz okoliša kao što je duhanski dim. U tu smo svrhu tijekom petomjesečnoga razdoblja nakon nezgode pratili smanjenje koncentracije hemoglobinskog adukta N-2-hidroksietilvalina usporedo s mjerenjem razina N-2-cijanoetilvalina i kotinina u mokraći, koji su pouzdani biomarkeri za dokazivanje pušenja duhana. Studija praćenja je pokazala da su koncentracije adukata etilen oksida značajno porasle nakon kratkotrajnoga izlaganja visokoj razini etilen oksida. U početnom biomonitoringu svih radnika izmjerene su razine N-2-hidroksietilvalina iznad 500 pmol g-1 globina, s maksimalnom vrijednošću od oko 2400 pmol g-1 globina. Ti su podaci usporedivi s vrijednostima njemačkih normi ekvivalenata izlaganja kancerogenim tvarima (EKA) od 90 μg L-1 krvi (~3900 pmol g-1 globina) kroz osmosatno dnevno izlaganje koncentraciji od 1 ppm etilen oksida. Razine adukata smanjile su se u skladu s očekivanom kinetikom nultoga reda za jednokratno izlaganje. Koncentracije N-2-hidroksietilvalina izmjerene u krvi radnika nakon petomjesečnoga praćenja mogu se povezati s njihovim osobnim pušačkim navikama. Rezultati toga istraživanja pokazuju da čak i kratkotrajna izloženost etilen oksidu može znatno povisiti razine adukata hemoglobina. Premda se u zdravstvenom nadzoru u okviru medicine rada proteinski adukti i njihove vrijednosti razmatraju u procjeni dugotrajnoga izlaganja, oni se mogu koristiti i za praćenje akcidentalnih izlaganja. U tim slučajevima izračun dnevnih vrijednosti (tzv. ppm-ekvivalenata) može poslužiti za usporedbu s postojećim procijenjenim vrijednostima

Mercapturic acids, protein adducts, and DNA adducts as biomarkers of electrophilic chemicals

The possibilities and limitations of using mercapturic acids and protein and DNA adducts for the assessment of internal and effective doses of electrophilic chemicals are reviewed. Electrophilic chemicals may be considered as potential mutagens and/or carcinogens. Mercapturic acids and protein and DNA adducts are considered as selective biomarkers because they reflect the chemical structure of the parent compounds or the reactive electrophilic metabolites formed during biotransformation. In general, mercapturic acids are used for the assessment of recent exposure, whereas protein and DNA adducts are used for the assessment of semichronic or chronic exposure. 2-Hydroxyethyl mercapturic acid has been shown to be the urinary excretion product of five different reactive electrophilic intermediates. Classification of these electrophiles according to their acid-base properties might provide a tool to predict their preference to conjugate with either glutathione and proteins or with DNA. Constant relationships appear to exist in the cases of 1,2-dibromoethane and ethylene oxide between urinary mercapturic acid excretion and DNA and protein adduct concentrations. This suggests that mercapturic acids in some cases may also play a role as a biomarker of effective dose. It is concluded that simultaneous determination of mercapturic acids, protein and DNA adducts, and other metabolites can greatly increase our knowledge of the specific roles these biomarkers play in internal and effective dose assessment. If the relationship between exposure and effect is known, similar to protein and DNA adducts, mercapturic acids might also be helpful in (individual) health risk assessment