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Mitochondrial DNA and electronic tracking reveal population structure of Atlantic bluefin tuna (Thunnus thynnus) 总被引:1,自引:0,他引:1
Population subdivision was examined in Atlantic bluefin tuna (Thunnus thynnus) through sequencing of the control region of the mitochondrial genome. A total of 178 samples from the spawning grounds in
the Gulf of Mexico, Bahamas and Mediterranean Sea were analyzed. Among the samples from these locations were 36 electronically
tagged bluefin tuna that were tagged in the North Atlantic and subsequently traveled to one of these known spawning grounds
during the spawning season. Bluefin tuna populations from the Gulf of Mexico and the Mediterranean Sea were found to be genetically
distinct based on Φst, and sequence nearest neighbor analyses, showing that these two major spawning areas support independent stocks. Sequence
nearest neighbor analysis indicated significant population subdivision among the Gulf of Mexico, western Mediterranean and
eastern Mediterranean Sea. However, it was not possible to find significant pairwise differences between any sampling areas
when using all samples. If only samples that had a high likelihood of assignment to a specific spawning site were used (young
of the year, spawning adults), the differentiation increased among all sampling areas and the Western Mediterranean Sea was
distinct from the Eastern Mediterranean Sea and the Gulf of Mexico. It was not possible to distinguish samples from the Bahamas
from those collected at any of the other sampling sites. These data support tagging results that suggested distinctness of
the Gulf of Mexico, Eastern and Western Mediterranean Sea spawning areas. This level of stock differentiation is only possible
if Atlantic bluefin tuna show strong natal homing to individual spawning grounds. 相似文献
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William R. Walker Carol J. Haley Phyllis Bridgeman Stephen H. Goldstein 《Environmental management》1991,15(3):441-449
A literature search and survey of Virginia, USA, campgrounds with RV pump-out stations were used to determine whether boat
holding-tank deodorant chemicals would have deleterious effects on marina septic systems or package treatment plants. Laboratory
studies reported in the literature indicate that these chemical additives could affect septic system function in three ways:
(1) active ingredients in the additives can impair sewage degradation in septic tanks, causing sludge buildup and overflow
of solids into the drainfield, (2) additive chemicals might enter the drainfield and, in high enough concentrations, reduce
the drainfield's ability to degrade waste, or (3) toxic additive chemicals might migrate from the drainfield to ground or
surface water. Laboratory studies also show that some ingredients added to holding tanks interfere with functioning of activated
sludge treatment process. Experience in the field and in other laboratory studies suggests that factors such as dilution of
treated waste with untreated waste and the characteristics of the sewage to be treated can reduce the possibility of damage
to septic and activated sludge systems. The campground owners surveyed indicated that they have few problems with their septic
systems in spite of the presence of chemical additives in the RV waste. However, most of them practice good septic system
maintenance and have devised other means of ensuring that their systems function efficiently. In addition, the survey indicates
that most Virginia campgrounds get only seasonal use (as would marinas in Virginia), allowing their systems to recover between
peak seasons. 相似文献
78.
- Cleanup of a contaminated site is halted as community residents launch a legal challenge against the method that those responsible for the site have selected for remediation.
- Parents and teachers at a public school call for an investigation to determine if substances in the building are making students and staff sick. Midway into the investigation, they also become concerned as to whether the right tests are being performed to detect contamination that may be present, and how they will know what the test results mean.
- Industrial neighbors of a facility oppose its air permit application out of concern for the effects the facility's emissions might have on their own workers.
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The value of quantitative and qualitative methods of cholinesterase (ChE) analysis in the detection of open neural tube defect (NTD) has been assessed in a prospective survey of 1495 mid-trimester amniotic fluids. Using a quantitative method the mean ChE values were much lower in fluids from pregnancies of normal outcome but it was not possible to discriminate these fluids completely from those associated with NTD pregnancies. particularly when the specimens were contaminated with blood. Similarly, measurement of acetylcholinesterase (AChE) activity alone by three different methods also failed to eliminate the overlap between the two groups. In contrast, polyacrylamide gel electrophoresis revealed only a single band of ChE activity in 1408 out of 1410 fluids from pregnancies with a normal outcome whilst amniotic fluids from all 60 cases of open NTD. 6 out of 7 cases of exomphalos and 3 out of 4 cases of intra-uterine death gave the characteristic second faster-running AChE band. A qualitative gel method which requires the same amount of ChE activity to be loaded from each amniotic fluid is an effective method for pre-natal diagnosis of NTDs. 相似文献