bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissues from routine pathology archives are suitable for microRNA analyses by quantitative PCR
Authors: Siebolts U , Varnholt H , Drebber U , Dienes H-P , Wickenhauser C , Odenthal M
Published: August 2008

Background:

MicroRNAs have recently taken centre stage as short non-coding RNAs that regulate mRNA expression.

Aim/Methods:

To assess the feasibility of using microRNA techniques on routinely processed tissues, the accessibility of two representative microRNAs was examined by real-time quantitative PCR in 86 human formalin-fixed paraffin-embedded (FFPE) samples from liver, breast, bone marrow, lymphatic tissues and colon. Murine liver was used to analyse the influence of fixation time and different fixatives.

Results:

High-quality microRNA was successfully extracted from routinely processed formalin-fixed tissues, resembling PCR amplification results from snap-frozen material analysed in parallel. While fixation time did not affect microRNA accessibility, non-buffered formalin or fixative supplements such as glutaraldehyde influenced PCR results. Storage of human tissues for up to 7 years did not cause a significant deterioration of microRNA. However, microRNA quality in human archival material following routine processing 10–20 years ago was decreased. Oxidation by ambient air during storage and fixation in non-buffered formalin is a possible reason for loss of microRNA quality.

Conclusion:

The assessment of microRNAs in readily obtained formalin-fixed paraffin-embedded samples is a highly promising tool in molecular pathology when similarly treated samples are analysed. Therefore, microRNA analyses will gain wider acceptance as an adjunct to morphological tissue assessment in routine pathology and retrospective studies.
Increased lymph node harvest from colorectal cancer resections using GEWF solution: a randomised study
Authors: Iversen L H , Laurberg S , Hagemann-Madsen R , Dybdahl H
Published: August 2008

Background:

The lymph node harvest from colorectal specimens is pivotal for patients with colorectal cancer (CRC), independent of N stage.

Aims:

To determine whether the use of GEWF solution (glacial acetic acid, ethanol, distilled water and formaldehyde) could improve the lymph node harvest in CRC specimens.

Methods:

Consecutive fresh colonic (n = 60) and rectal (n = 60) specimens from patients with primary CRC resected at Aarhus University Hospital THG between March 2006 and July 2007 were randomised to either conventional preparation or GEWF preparation and examined in a standard manner.

Results:

For colonic as well as rectal specimens, the GEWF solution increased the mean lymph node harvest from 9 and 10 to 16 and 17 lymph nodes per specimen compared to conventional prepared specimens (p<0.001). Using the recommended threshold of 12 lymph nodes to ensure adequacy of nodal harvest, the adequacy increased from less than half to almost three quarters independent of tumour origin (p<0.037). The proportion of node-negative specimens was not significantly different between the two preparation groups.

Conclusion:

The use of GEWF solution in patients with CRC significantly increases the lymph node harvest of resected specimens.
Research ethics committees: the role of ethics in a regulatory authority
Authors: McGuinness S
Published: August 2008

This paper is an examination of how research ethics committees have evolved from being advisory committees to more formal regulatory authorities. It is argued that the role of ethics committees should be broader than simple ethical review. Inconsistency in outcome should not be taken to signal failure. Procedural fairness is of the utmost importance. Nor should ethics committees be seen to diminish the ethical responsibilities of researchers themselves.
From compulsory to voluntary immunisation: Italy’s National Vaccination Plan (2005–7) and the ethical and organisational challenges facing public health policy-makers across Europe
Authors: Moran N E , Gainotti S , Petrini C
Published: August 2008

Increasing geographical mobility and international travel augment the ease and speed by which infectious diseases can spread across large distances. It is therefore incumbent upon each state to ensure that immunisation programmes are effective and that herd immunity is achieved. Across Europe, a range of immunisation policies exist: compulsion, the offer of financial incentives to parents or healthcare professionals, social and professional pressure, or simply the dissemination of clear information and advice. Until recently, immunisation against particular communicable diseases was compulsory in Italy. The Italian National Vaccination Plan (NVP) (2005–7) paved the way for regions to suspend the sanctions associated with compulsory vaccinations for children when certain criteria are met—for example when immunisation coverage is high and when effective monitoring/surveillance systems are in place—and thus marked a milestone in the move from compulsory to voluntary immunisation. The forthcoming NVP for 2008–10 confirms the liberal approach to vaccination in Italy as it entrusts to the regions responsibility for the achievement and maintenance of herd immunity. This paper reviews the arguments for and against compulsory and voluntary immunisation in relation to the Italian NVP (2005–7) and in the context of the diverse immunisation policies that exist across Europe. It concludes with cautious support for the NVP and an associated shift from compulsory to voluntary immunisation in Italy, and draws similarities between issues concerning regional variation in immunisation policy in Italy and national variation in immunisation policy across Europe and beyond.
Ethical reflections on clinical trials with human tissue engineered products
Authors: Trommelmans L , Selling J , Dierickx K
Published: August 2008

Ex-vivo tissue engineering is an emerging medical technology. Its aim is to regenerate tissues and organs and to restore them to full physiological activity. Some clinical trials with human tissue engineered products (HTEPs) have been conducted and others will follow. These trials not only have to confirm the therapeutic value of the HTEP, they also have to provide insight in its regenerative activity, its safety and long-term effects. The development of these trials is aggravated by the complexity of the tissue engineering process and product. This paper investigates how this complexity influences the ethical conduct of clinical trials with HTEPs. We focus on the value and validity of the trial, the risk-benefit ratio and the protection of the trial participant. We argue that trials with HTEPs need a robust methodology. The risk-benefit ratio of a new HTEP must be determined and compared with available efficacious therapies. This requires the identification and minimisation of risks associated with tissue engineering. Finally a process as complex as tissue engineering presents serious challenges for the informed consent process, and for the protection of the trial participant during and after the trial.
Should individuals choose their definition of death?
Authors: Molina A , Rodríguez-Arias D , Youngner S J
Published: August 2008

Alireza Bagheri supports a policy on organ procurement where individuals could choose their own definition of death between two or more socially accepted alternatives. First, we claim that such a policy, without any criterion to distinguish accepted from acceptable definitions, easily leads to the slippery slope that Bagheri tries to avoid. Second, we suggest that a public discussion about the circumstances under which the dead donor rule could be violated is more productive of social trust than constantly moving the line between life and death.
Adding insult to injury: the healthcare brain drain
Authors: Hooper C R
Published: August 2008

Recent reports published by the United Nations and the World Health Organization suggest that the brain drain of healthcare professionals from the developing to the developed world is decimating the provision of healthcare in poor countries. The migration of these key workers is driven by a combination of economic inequalities and the recruitment policies of governments in the rich world. This article assesses the impact of the healthcare brain drain and argues that wealthy countries have a moral obligation to reduce the flow of healthcare workers from the developing to the developed world.
Information and consent for newborn screening: practices and attitudes of service providers
Authors: Kerruish N J , Webster D , Dickson N
Published: August 2008

Objectives:

To gather information about the practices and attitudes of providers of maternity care with respect to informed consent for newborn screening (NBS).

Methods:

A questionnaire concerning information provision and parental consent for NBS was sent to all 1036 registered lead maternity carers (LMC) in New Zealand.

Results:

93% of LMC in New Zealand report giving parents information concerning NBS, most frequently after delivery (73%) and in the third trimester (60%). The majority (85%) of LMC currently obtain some form of consent (verbal or written) for NBS from parents and consider this to be the ideal approach (94%). Despite this a significant minority of LMC (23%) reported considering that NBS should be mandatory. Of those in our survey who believed that NBS should be mandatory, paradoxically most (89%) still believed that some form of parental consent should be obtained; of those who believed testing should not be mandatory, only a small proportion (10%) would accept parental refusal without question.

Conclusions:

When the results of this survey are considered in conjunction with existing evidence there appears to be a consensus that good quality information in the prenatal period should be an integral part of any NBS programme. The issue of consent is more complex and there is less agreement on the preferred degree of parental involvement in decisions to allow babies to undergo NBS. A policy that both strongly recommends NBS but also allows parental choice appears to be most consistent with the views of LMC in this survey.
Informed consent in clinical research in France: assessment and factors associated with therapeutic misconception
Authors: Durand-Zaleski I S , Alberti C , Durieux P , Duval X , Gottot S , Ravaud Ph , Gainotti S , Vincent-Genod C , Moreau D , Amiel P
Published: August 2008

Background:

Informed consent in clinical research is mandated throughout the world. Both patient subjects and investigators are required to understand and accept the distinction between research and treatment.

Aim:

To document the extent and to identify factors associated with therapeutic misconception in a population of patient subjects or parent proxies recruited from a variety of multicentre trials (parent studies).

Patients and methods:

The study comprised two phases: the development of a questionnaire to assess the quality of informed consent and a survey of patient subjects based on this questionnaire.

Results:

A total of 303 patient subjects or parent proxies were contacted and 279 questionnaires were analysed. The median age was 49.5 years, sex ratio was 1 and 61% of respondents were professionally active. Overall memorisation of the oral or written communication of informed consent was good (69–97%), and satisfaction with the process was around 70%. Therapeutic misconception was present in 70% of respondents, who expected to receive better care and ignored the consequence of randomisation and treatment comparisons. This was positively associated with the acuteness and severity of the disease.

Conclusion:

The authors suggest that the risk of therapeutic misconception be specifically addressed in consent forms as an educational tool for both patients and investigators.
Clinical research projects at a German medical faculty: follow-up from ethical approval to publication and citation by others
Authors: Blümle A , Antes G , Schumacher M , Just H , von Elm E
Published: August 2008

Background:

Only data of published study results are available to the scientific community for further use such as informing future research and synthesis of available evidence. If study results are reported selectively, reporting bias and distortion of summarised estimates of effect or harm of treatments can occur. The publication and citation of results of clinical research conducted in Germany was studied.

Methods:

The protocols of clinical research projects submitted to the research ethics committee of the University of Freiburg (Germany) in 2000 were analysed. Published full articles in several databases were searched and investigators contacted. Data on study and publication characteristics were extracted from protocols and corresponding publications.

Results:

299 study protocols were included. The most frequent study design was randomised controlled trial (141; 47%), followed by uncontrolled studies (61; 20%), laboratory studies (30; 10%) and non-randomised studies (29; 10%). 182 (61%) were multicentre studies including 97 (53%) international collaborations. 152 of 299 (51%) had commercial (co-)funding and 46 (15%) non-commercial funding. 109 of the 225 completed protocols corresponded to at least one full publication (total 210 articles); the publication rate was 48%. 168 of 210 identified publications (80%) were cited in articles indexed in the ISI Web of Science. The median was 11 citations per publication (range 0–1151).

Conclusions:

Results of German clinical research projects conducted are largely underreported. Barriers to successful publication need to be identified and appropriate measures taken. Close monitoring of projects until publication and adequate support provided to investigators may help remedy the prevailing underreporting of research.
Contractual obligations and the sharing of confidential health information in sport
Authors: Anderson L
Published: August 2008

As an employee, a sports doctor has obligations to their employer, but also professional and widely accepted obligations of a doctor to the patient (in this case the individual team member). The conflict is evident when sports doctors are asked by an athlete to keep personal health information confidential from the coach and team management, and yet both doctor and athlete have employment contracts specifying that such information shall be shared. Recent research in New Zealand shows that despite the presence of an employment contract, there appears to be a wide range of behaviours among sports doctors when an athlete requests that information about them be kept from team management. Many seem willing to honour requests to keep health information about the athlete confidential, thereby being in breach of the employment contract, while others insist on informing team management against the wishes of the athlete. There are a number of potential solutions to this dilemma from forcing doctors to meet their contractual obligations, to limiting the expectations of the employment contract. This paper suggests that at times it may be appropriate to do both, making the position of the doctor clearer and supporting the ability of this group to resist pressure by coaches and management through having a robust code of ethics.
Numerical Classification of Sharp-beaked Redfishes, Sebastes mentella and S. fasciatus, from Northeastern Grand Bank
Authors: Ni I-H.
Published: August 2008

The distinction between Sebastes fasciatus and S. mentella has not previously been clearly established as good morphological discriminators had not been isolated. Eleven meristic and 14 morphological characters were examined individually (univariate statistics) and collectively (discriminant analysis) on 200 sharp-beaked redfish specimens representing both S. fasciatus and S. mentella which had been separated by the anatomical character of extrinsic gasbladder musculature. The result of the discriminant analysis demonstrated good (100%) separation of redfish with combinations of meristic and morphological characters. Anal fin rays, relative position of pectoral and pelvic fin to anus, number of the first left gill rakers, angle of the third preopercular spine, the fusion of the occipital–nuchal ridge, and vertebral number were good discriminators between S. mentella and S. fasciatus.Key words: Sebastes fasciatus, S. mentella, redfish, taxonomy, morphology, identification, discriminant analysis
Patterns of Invertebrate Size and Abundance in Aquatic Habitats
Authors: Mittelbach Gary G.
Published: August 2008

The size distributions of invertebrate prey found in the vegetation, bare sediment, and open water habitats of a small, Michigan lake were quantified for the months of May through August, 1979. The distribution of prey body size in each habitat generally conformed to a lognormal distribution, allowing a simple characterization of prey size and abundance in each habitat. Seasonally, the abundance of large littoral invertebrates declined markedly, shifting the distribution of prey size in the vegetation and bare sediment habitats towards smaller prey. The total biomass of vegetation-dwelling prey (exclusive of gastropods) also declined dramatically from May to August. These seasonal changes in prey size and abundance were correlated with a reduction in foraging intake for the dominant fish species in the lake, the bluegill sunfish (Lepomis macrochirus). Bluegills whose diet was > 80% vegetation prey showed a > 3-fold decline in stomach contents (prey weight/fish weight) from May to Ausut, during which time prey biomass in the vegetation declined 2.5-fold.Key words: body size, lognormal distribution, benthos, foraging, Lepomis, Michigan
Uptake of Cadmium in Perfused Rainbow Trout (Salmo gairdneri) Gills
Authors: Pärt P. , Svanberg O.
Published: August 2008

Uptake of cadmium in gills from rainbow trout (Salmo gairdneri) has been studied by the head perfusion technique. The importance of checking the viability of the perfused gills is considered and some viability criteria are discussed. The results show that cadmium is transferred through perfused gills. A 10-fold increase in the external Cd concentration from 5 × 10−8 to 5 × 10−7 mol∙L−1 resulted in a nearly 100-fold increase in cadmium transfer. At higher cadmium concentrations the uptake rate of the element diminished after having reached a maximum within 30 min. A complexing agent, EDNTA, which strongly chelates free cadmium ions decreases the transfer of cadmium through the gills. The advantage of using in vitro techniques instead of conventional uptake experiments is discussed and it is concluded that the gill perfusion technique is a useful tool in studies of factors affecting heavy metal uptake in fish.Key words: perfusion technique, fish gills, Salmo gairdneri, cadmium uptake, viability, EDNTA
Establishment of Walking Catfish (Clarias batrachus) Cell Lines and Development of a Channel Catfish (Ictalurus punctatus) Virus Vaccine
Authors: Noga Edward J. , Hartmann James X.
Published: August 2008

Cell lines from apparently normal gill, gonad, and kidney tissue of adult walking catfish (Clarias batrachus) were established and have been subcultured 75, 80, and 95 times, respectively. The cells were propagated in a modified Ham's F-12 medium at 25 °C but are capable of growth at 37 °C. The gill and kidney cells are the first to have been established from these tissues in fish. The kidney cell line is fibroblastic, the gonad is a mixed epithelioid–fibroblastic type, and the gill is pleomorphic. All three cell lines are susceptible to channel catfish virus (CCV), exhibiting cell fusion and other marked cytopathic effects. A live attenuated vaccine strain of CCV was produced by repeated passage of a virulent strain of CCV in kidney cell cultures. The vaccine strain is less virulent than the wild-type CCV and protects fingerling catfish against challenge with wild-type virus.Key words: channel catfish virus, Clarias batrachus, fish cell cultures, vaccine
Fate of Kepone and Mirex in a Model Aquatic Environment: Sediment, Fish, and Diet
Authors: Skaar Donald R. , Johnson B. Thomas , Jones John R. , Huckins James N.
Published: August 2008

Laboratory studies of freshwater sediment and a daphnid–bluegill (Daphnia magna–Lepomis macrochirus) food chain indicated that the organochlorine insecticides Kepone and mirex resist microbial degradation, accumulate and resist metabolism in fish, and move through a food chain. We found no direct evidence of degradation of either compound after 56 d of incubation in freshwater sediments under aerobic or anaerobic conditions. Furthermore, we found no metabolism or co-metabolism of 14C-labeled Kepone in sediments that had long-term preexposure to Kepone and by-products nor did we detect a selective process occurring in the sediments that changed the capacity of the autochthonous microbiota to metabolize Kepone. After 28 d of exposure to 14C-labeled Kepone or mirex in water and natural food, bluegills accumulated Kepone and mirex equal to 10 606 and 12 274 times the respective exposure concentrations. Elimination patterns were dissimilar: mirex tended to persist in fish tissue but Kepone did not. Neither Kepone nor mirex was metabolized by bluegills. Retention of mirex introduced into bluegills by daphnids was about 3 times greater than that of Kepone. Accumulation of Kepone and mirex by bluegills was about half that of DDT.Key words: Kepone, mirex, degradation, freshwater sediment, accumulation, elimination, bluegills, daphnids, residue dynamics, food chain, accumulation index
Introgressive Hybridization in Populations of Paiute Cutthroat Trout (Salmo clarki seleniris)
Authors: Busack Craig A. , Gall G. A. E.
Published: August 2008

Two populations of Paiute cutthroat trout (Salmo clarki seleniris) were compared meristically and electrophoretically with Lahontan cutthroat (S. c. henshawi) and rainbow trout (S. gairdneri) to elucidate population structure and verify the occurrence of introgressive hybridization. In Silver King Creek, both meristic and electrophoretic evidence indicated two populations were present, one appearing to be pure Paiute cutthroat, the other Paiute cutthroat introgressed with rainbow trout. Lahontan cutthroat introgression was a possibility in Silver King Creek but could not be evaluated because of the strong meristic and electrophoretic similarity of Paiute and Lahontan cutthroat. The other Paiute population, Cottonwood Creek, meristically appeared to be pure Paiute cutthroat but electrophoretic data indicated it was introgressed with rainbow trout. The existence of the two Silver King Creek populations indicated introgression was incomplete in that stream; introgression appeared to be complete in Cottonwood Creek. The meristic similarity of Cottonwood Creek trout to pure Paiute cutthroat was probably a result of strong selection by management agencies for a Paiute cutthroat phenotype. Electrophoresis was more discriminating than meristic analysis in this study in detecting introgression. Electrophoresis also allowed more detailed analysis of population structure than meristics because of the difference in complexity of the genetic systems analyzed by the two techniques. However, the application of both techniques contributed greatly to our understanding of introgression in the Paiute cutthroat and demonstrated the complementarity of the two approaches.Key words: Salmo clarki, Salmo gairdneri, Paiute cutthroat, Lahontan cutthroat, meristics, electrophoresis, introgression, hybridization, gametic disequilibrium, principal components
Reproductive Uncertainty and the Evolution of Iteroparity: Why Don't Flatfish Put All Their Eggs in One Basket?
Authors: Roff Derek A.
Published: August 2008

Murphy's hypothesis that variation in reproductive life span is an adaptive response to variation in the predictability of reproductive success is examined. Murphy's contention that this hypothesis explains the variation in reproductive life span within the clupeids is reexamined incorporating further data on the Peruvian anchovy (Engraulis ringens). A nonsignificant correlation is now obtained between reproductive life span and brood strength variation; thus, the hypothesis is called into question. An alternative explanation is presented that considers the interaction between life history parameters: because it is necessary for the intrinsic rate of increase to exceed zero, variation in one parameter must be associated with variation in at least one other parameter. In the clupeids it is noted that the age of maturity and reproductive life span vary in concert and it is suggested that this provides an explanation of variation in reproductive life span. These two hypotheses are examined using data on the family Pleuronectidae, the flatfish. No correlation exists between reproductive life span and the degree of fluctuation in brood strength but there is a significant correlation between reproductive life span and age of maturity. It is concluded that variation in reproductive life span within the flatfish group is not a response to variation in reproductive success but rather a correlate of variation in age of maturity.Key words: flatfish, Pleuronectidae, iteroparity, natural selection, reproduction, clupeids
A Method for Comparing the Precision of a Set of Age Determinations
Authors: Beamish R. J. , Fournier D. A.
Published: August 2008

An index of average percent error is a better estimate of the precision of age determinations than the conventional percent agreement method because it is not independent of the age of a species.Key words: age determination, aging errors
Abundance, Life History, and Growth of Introduced Populations of the opossum shrimp (Mysis relicta) in Subalpine California Lakes
Authors: Morgan Mark D.
Published: August 2008

The opossum shrimp, Mysis relicta, was introduced into Donner Lake and Fallen Leaf Lake, California, in 1965. Samples from both lakes in August 1978 and June 1979 and from Donner Lake in November 1980, reveal that the mysids are established throughout each lake. In Donner Lake, the estimated overall lakewide density was 238/m2 in August 1978, 123/m2 in June 1979, and 108/m2 in November 1980. In Fallen Leaf Lake, the overall lakewide density was 114/m2 in August 1978 and 103/m2 in June 1979. Mysids in both populations lived for 2 yr and reproduced each spring at 1 and 2 yr of age. Growth was fastest in the spring and summer and slowest in the fall and winter. Previously published data suggest that mysid life history traits can be predicted based on the productivity of the lake. This study supports this view. When productivity is relatively high, the life cycle lasts from 1 to 2 yr, but when productivity is low, it may take up to 4 yr.Key words: Mysis relicta, life history, species introduction, fisheries management, Fallen Leaf Lake, Donner Lake, Lake Tahoe
Absorption of Selected Antimicrobic Drugs from Water by Channel Catfish, Ictalurus punctatus
Authors: Nusbaum Kenneth E. , Shotts jr. Emmett B.
Published: August 2008

Although anitmicrobial drugs are frequently added to water to treat bacterial diseases of fish, their absorption is largely unquantified. Channel catfish weighing 3–5 g each were exposed to varying concentrations (4 mg/L to 32 mg/L) of chloramphenicol, erythromycin, furpyrinol, and oxytetracycline, respectively. Antibiotic levels measured after 5 h utilizing Bacillus subtilus spore germination inhibition showed that furpyrinol and oxytetracycline were absorbed by the fish in proportion to the antimicrobial concentration in the water. Minimum inhibitory concentrations can be attained in the fish with practical concentrations of these drugs in the water. Erythromycin (carrier-free) was poorly absorbed and chloramphenicol was not absorbed. Significant antibiotic degradation in water occurred in all drugs except furpyrinol.Key words: fish, antimicrobic, chloramphenicol, erythromycin, furance, oxytetracycline
Determination of Free Metal Ion Concentrations Using Bioassays
Authors: Borgmann Uwe
Published: August 2008

A procedure was developed by which free metal ion concentrations, toxic to aquatic life, can be calculated by comparing metal toxicity before and after addition of a complexing agent of known complexing capacity. Application of this method suggests that the growth of freshwater copepods is affected at free copper concentrations around 10−10 to 10−9 mol∙L−1. In natural waters, with unidentified ligands of unknown complexing ability, this procedure provides the only method currently available for estimating free metal concentrations at the low levels often causing sublethal toxicity to aquatic organisms.Key words: metal toxicity, complexation, free metal, copepods, copper
Predicting Encounter Rates for Zooplankton: A Model Assuming a Cylindrical Encounter Field
Authors: Giguère Louis A. , Delâge André , Dill Lawrence M. , Gerritsen Jeroen
Published: August 2008

We delimit a cylindrical attack field for a Chaoborus larva feeding on zooplankton, and propose a mathematical model to predict encounter rates with prey for this ambush predator. The model is based on the encounter process between a stationary cylinder and spheres moving at constant velocity in random directions. The predictions of the model are corroborated in the laboratory.Key words: zooplankton, encounter model, Chaoborus, ambush predator, copepod
Use of Cycle Dummy Variables and Race Escapement in the Fraser River Sockeye Salmon (Oncorhynchus nerka) Recruitment Function
Authors: Gardner Peter N.
Published: August 2008

The recruitment function for the Fraser River sockeye salmon (Oncorhynchus nerka) stock was estimated by allowing cycle differences between year-classes to be represented by dummy variables, by allowing the effects of weight on cycle year differences to be included through the use of biomass forms of the variables, and by disaggregating year-class escapement by race according to freshwater lake residence to represent differences between races. Comparisons were made with the conventional model.Key words: year-class cycle dummies, biomass variables, race escapements, sockeye salmon
Juvenile Salmon Residency in a Marsh Area of the Fraser River Estuary
Authors: Levy D. A. , Northcote T. G.
Published: August 2008

Large numbers of juvenile chinook salmon (Oncorhynchus tshawytscha), chum salmon (O. keta), and pink salmon (O. gorbuscha) were present within tidal channels of a marsh area in the Fraser Estuary between March and June 1978. The tidal channels investigated dewatered at low tide, necessitating daily emigrations by juvenile salmon out of the channels. While pink fry emigrated from tidal channels at the early and middle stages of ebbing tides, most chum and chinook fry emigrated near the later stages of ebbing tides. Mark–recapture studies demonstrated that chinook and chum fry resided temporarily in the marsh prior to migrating into the Pacific Ocean and returned to the same channel on several tidal cycles. Pink fry were abundant in the channels, but appeared to be transient. Chinook and chum showed an increase in average length which was attributable to estuarine growth.Key words: chinook salmon, chum salmon, pink salmon, juvenile residency, marsh tidal channel, Fraser Estuary, estuary growth
Overestimation of Orthophosphorus Concentrations in Surface Waters of Southern Lake Michigan: Effects of Acid and Ammonium Molybdate
Authors: Tarapchak Stephen J. , Bigelow Sylvia M. , Rubitschun Cora
Published: August 2008

Water from southern Lake Michigan was analyzed to determine if orthophosphorus (PO4-P) concentrations are overestimated by molybdenum blue methods and to assess the potential effects of ammonium molybdate on soluble reactive phosphorus (SRP) determinations. Time-course "hydrolysis" tests, based on the Chamberlain–Shapiro extraction method, showed that large amounts of PO4-P were released from bound sources into solution within seconds after acid molybdate was added, and that molybdate-reactive PO4-P could be retained by filters or released from particulate material into filtrates during filtration. PO4-P concentrations obtained by using the prescribed exposure of 30 s were overestimated minimally by up to 86%, and ammonium molybdate dramatically accelerated PO4-P release in filtered samples. Tests using up to a fourfold range in ammonium molybdate concentrations also showed that the extraction method and Harvey's method yielded SRP values that varied two- to three-fold or more, and that most of the PO4-P was released from "particles" in filtrates. Analytical methods, therefore, can yield substantially different SRP estimates because of differences in the length of time samples are exposed to acid molybdate and because of differences in molybdate concentrations.Key words: ammonium molybdate, hydrolysis, phosphorus, soluble reactive phosphorus, orthophosphorus
Community Structure and Biomass of Euphausiids in the Bay of Fundy
Authors: Kulka D. W. , Corey S. , Iles T. D.
Published: August 2008

Seven species of euphausiids were found in the Bay of Fundy: Meganyctiphanes norvegica, Thysanoessa inermis, T. longicaudata, T. raschii, T. gregaria, Euphausia krohnii, and Nematoscelis megalops (listed in descending order of abundance). A high-intensity sampling scheme during November and March facilitated detailed distributional studies which revealed that M. norvegica, T. inermis, and T. longicaudata each had a specific stationary center of abundance in the study area, and each species performed a different pattern of diurnal vertical migration. Meganyctiphanes norvegica formed 90% (constituting 70 kt) of the euphausiids. The last four species were occasional immigrants from areas south of the Bay of Fundy. From the relationships between life history stages, vertical migration patterns, distribution, and currents in the Fundy Region, we suggest that these euphausiid species form stocks.Key words: euphausiids, Meganyctiphanes norvegica, Thysanoessa inermis, Thysanoessa longicaudata, biomass, community structure, stock, Bay of Fundy
Comparison of Two Sampling Methods for Estimating the Abundance and Distribution of Mysis relicta
Authors: Nero R. W. , Davies I. J.
Published: August 2008

Vertical net hauls taken at night yielded a population estimate for Mysis relicta of 5 300 000 ± 1 060 000 (P ≤ 0.05) while quadrat counts done by SCUBA divers in the daytime fixed the population size at 1 100 000 ± 170 000. Observations by divers suggested that the behavior and distribution of Mysis during the day resulted in an underestimate of their abundance by the quadrat method. Net hauls showed that at night mysids migrated both vertically to the base of the epilimnion and horizontally within the metalimnion. A vertical tow rate of [Formula: see text] m∙s−1 used for the nighttime population estimates lay within the optimum sampling speed of the net. Repeated sampling at a single station had little or no effect on catch totals for up to nine consecutive hauls. Beyond this number some local depletion was noted. A modified vertical tow net which sampled on descent then closed once contact was made with the substrate performed no better than a standard net except when the shallowest stations were sampled repeatedly. Temporal variation in the catch of young-of-the-year Mysis at shallow stations, however, contributed at most ± 8% error to the whole lake population estimate.Key words: Mysidacea, diurnal migration, samplers, SCUBA, vertical net tows
Stream Regulation Alters Acute Temperature Preferenda of Red Shiners, Notropis lutrensis
Authors: Calhoun Stuart W. , Zimmerman Earl G. , Beitinger Thomas L.
Published: August 2008

Acute selected temperatures at acclimation states of 10, 20, and 30 °C were significantly different (P < 0.05) between red shiners (Notropis lutrensis) from an unregulated stream and a stream below a hypolimnion-release reservoir in north central Texas. Estimated final temperature preferenda for the two populations were 30.0 and 23.3 °C, respectively. These results support the hypothesis that temperature selection behavior in this species is mutable and subject to regulation by natural selection. We hypothesize that the lower thermal preferendum of tailwater populations represents an adaptive response to a depressed thermal regime typical of hypolimnion-release reservoirs.Key words: temperature preferendum, regulated stream, red shiner, Notropis lutrensis
Empirical Estimates of Carbon Production for a Meiobenthic Harpacticoid Copepod
Authors: Feller Robert J.
Published: August 2008

The intertidal harpacticoid copepod Huntemannia jadensis was sampled at approximately weekly intervals with five replicate cores at mean lower low water stations on three similar sand beaches in Puget Sound, Washington, from 1973 to 1974. Quantitative estimates of abundance of each developmental stage and direct measures of body carbon were used to calculate secondary production by two methods, one of which required knowledge of development times. Population biomass varied fivefold during the year. Production ranged from 0.75 to 1.75 mg C∙10 cm−2∙yr−1, varying with study area and computation method. Confidence intervals about single production estimates were extremely high, and 95% confidence limits about annual production estimates were 0.2–14.7 mg C∙10 cm−2∙yr−1. Turnover ratios for this harpacticoid were about 4 per year, low in comparison with other meiofaunal species. Eggs and naupliar growth accounted for ~50% of total annual production.Key words: meiobenthos, secondary production, harpacticoid copepod, carbon, P/B ratio, Puget Sound
Competitive Interactions Between Benthic Stream Fishes, Riffle Sculpin, Cottus gulosus, and Speckled Dace, Rhinichthys osculus
Authors: Baltz Donald M. , Moyle Peter B. , Knight Ned J.
Published: August 2008

Two morphologically dissimilar stream fishes occupied the same microhabitat in different riffles of Deer Creek, Tehama County, California. In a 12.5 km reach of the creek, speckled dace (Rhinichthys osculus) dominated riffles at the lower end while riffle sculpin (Cottus gulosus) dominated the riffles at the upper end, where dace were confined to slower water. Between these sets of riffles, relative abundances of the two species were negatively correlated. Routine metabolic rates of sculpin increased rapidly with temperature and indicated that sculpins were unable to tolerate temperatures in the low elevation riffles in the summer. Dace swimming performance appeared to be adequate at low temperatures to permit them to occupy the sculpin-dominated riffles. However, stream tank experiments indicated that at low temperatures sculpin were able to displace dace from cover in high velocity water. Our analysis thus demonstrated that competitive interactions between dace and sculpin for preferred microhabitat were mediated by temperature.Key words: competition, critical swimming velocity, experimental stream, microhabitat utilization, routine metabolism
Predation by Medusae on Pacific Herring (Clupea harengus pallasi) Larvae
Authors: Arai Mary Needler , Hay Douglas E.
Published: August 2008

In laboratory tests young Pacific herring (Clupea harengus pallasi) larvae were eaten by several species of hydromedusae common in coastal waters off British Columbia, including the previously controversial Sarsia tubulosa and by the scyphomedusa Aurelia aurita. Field collections and observations confirmed that the distributions of medusae and larvae overlap and that some medusae feed on herring larvae in nature. In coastal waters and bays of British Columbia, the hydromedusae Sarsia tubulosa or Aequorea victoria may be most abundant during the time of peak herring larvae abundance.Key words: herring, larvae, Clupea, Sarsia, Aequorea, predation, medusae
A Multilocus Genetic Model Applied to the Effects of Selective Fishing on the Growth Rate of Trout
Authors: Favro L. D. , Kuo P. K. , McDonald J. F. , Favro D. D. , Kuo A. D.
Published: August 2008

We used a generalized genetic model with varying numbers of genes to investigate the effects of selective fishing on the growth rate of trout. Our results indicate that the effects are not highly dependent on the details of the genetic model. In particular, the size distribution of the population in the long run seems to be insensitive to the number of active loci which control the growth rate of the fish.Key words: fish, trout, genetics, growth, size limit, population
Effects of Predation Risk and Parasitism on the Feeding Ecology, Habitat Use, and Abondance of Lacustrine Threespine Stickleback (Gasterosteus aculeatus)
Authors: Jakobsen Per Johan , Johnsen Geir Helge , Larsson Petter
Published: August 2008

From 1980 to 1985, we investigated a lacustrine population of threespine stickleback (Gasterosteus aculeatus) with respect to densities, individual length, distribution, diet, frequency of parasitism by Schistocepbalus solidus, and selective predation by Atlantic salmon (Salmo salar). From these investigations we concluded the following. (1) When stickleback are forced into the littoral zone by salmon, competition in this restricted area increases, or alternatively, stickleback distribute themselves in an area with less profitable prey. This, combined with predation from salmon, results in a population decline and reduced growth of the stickleback. (2) At least in autumn, parasitized stickleback distribute themselves in areas with high predation risk from salmon; when exposed to salmon predation, parasitized stickleback are preyed upon at a higher rate than healthy ones. Hence, parasitized individuals have almost disappeared from the stickleback population in Lake Kvernavann, Norway.
Movements of Atlantic Halibut (Hippoglossus hippoglossus) in the Canadian North Atlantic
Authors: Stobo Wayne T. , Neilson John D. , Simpson Patricia G.
Published: August 2008

The results of Atlantic halibut (Hippoglossus hippoglossus) tagging experiments conducted in Northwest Atlantic Fisheries Organization (NAFO) Subareas 3 and 4 between 1958 and 1973 were reexamined. Data from the 230 recaptures indicated a tendency for fish released on the Scotian Shelf to move to the northeast, while fish released on the Newfoundland Grand Bank showed no preferred direction of movement. The Laurentian Channel does not appear to be a barrier to migration for this species. Small (<75 cm) fish moved further than larger fish. The seemingly limited movement by larger fish may be due to acyclic annual migration between feeding and spawning grounds, similar to that suggested for Pacific halibut (Hippoglossus stenolepis). The extensive movement of Atlantic halibut throughout most of the Canadian Northwest Atlantic suggests that a single area would be the most feasible management unit, encompassing the Scotian Shelf and southern Grand Bank regions.
Effects of Logging on Stream Temperatures in Carnation Creek British Columbia, and Associated Impacts on the Coho Salmon (Oncorhynchus kisutch)
Authors: Holtby L. Blair
Published: August 2008

Clear-cut logging of 41% of the basin of Carnation Creek, British Columbia, resulted in increased stream temperatures in all months of the year, increases above prelogging temperatures ranged from 0.7 °C in December to 3.2 °C in August. Earlier emergence of coho salmon (Oncorhynchus kisutch) fry associated with the temperature increases lengthened their summer growing season by up to 6 wk. Fingerlings were significantly larger by the fall in the years after logging compared with the years before logging. The increased size of fingerlings was associated with improved overwinter survival. Following logging, yearling smolt numbers doubled, although 2-yr-old smolt numbers decreased. Warmer spring temperatures were also associated with earlier seaward migration of smolts, probably resulting in decreased smolt-to-aduit survivals. A linked series of models that first predict logging effects on stream temperatures and then the effects of those temperatures on critical coho life history events are developed. The life history model is used to quantify the effects of stream temperature changes related to logging on the population size of adult coho salmon. The predicted effect of those temperature changes was a 9% increase in adult coho numbers prior to the fishery, an increase considerably less than the observed 47% increase in smolt numbers.
Sensitivities and Variances of Virtual Population Analysis As Applied to the Mackerel, Scomber japonicus
Authors: Prager Michael H. , MacCall Alec D.
Published: August 2008

Virtual population analysis (VPA) is widely used in fish stock assessment. However, VPA results are generally presented as point estimates, without error variance. Using numerical methods, we estimated the total variance of historical (1929–65) biomass estimates of mackerel, Scomber japonicus, off southern California. In the years before 1940, coefficients of variation (CV's) approached 100%; later, when weights at age and the age structure of the catch were better known, the CV's were about 25%. Most of the variability derives from uncertainties in estimates of natural mortality (M) and of weights at age. We also developed dimensionless coefficients (sensitivities) to examine the effects of errors in the inputs on the VPA biomass estimates. The largest sensitivities were to M and the total catch and varied substantially from year to year. As expected, sensitivity to M decreased with increasing exploitation, and sensitivity to catch increased with increasing exploitation. Using such sensitivities, one could estimate the error in a biomass estimate for a past year when M (or any other input) was thought to be unusually high or low. Thus, retrospective corrections can be made. Also, such sensitivities form an analytic tool for examining the properties of VPA, or any quantitative model.
Digestive Tract Evacuation in Northern Squawfish (Ptychocheilus oregonensis)
Authors: Beyer Jean M. , Lucchetti Gino , Gray Gerry
Published: August 2008

Digestive tract evacuation in northern squawfish (Ptychocheilus oregonensis) (170–1900 g) was studied in fish allowed to feed voluntarily on salmon (4–70 g) at three water temperatures (10, 15, and 20 °C). Squawfish were sacrificed at 1- or 2-h intervals until evacuation approximated 90%. Amount of food evacuated for a given time interval increased approximately three times as the temperature was increased and as the prey weight was increased and two times as the predator weight was increased. The 90% emptying time (ET90) decreased by about two thirds as the temperature doubled and by about one half as the predator weight increased 10 times, but approximately doubled when the prey weight increased 4 times. Two-fish meals (17–20 g each, 35–39 g total) were evacuated more slowly than meals of one fish weighing 17–20 g, but at the same rate as meals of one fish weighing 35–40 g. Equations derived are easily applied to a wide range of water temperatures, prey weights, and predator weights.
Comparison of Productivity Estimates for Laminaria in Nova Scotia
Authors: Smith Barry D.
Published: August 2008

An estimate of productivity for a southwestern Nova Scotia Laminaria community was obtained using a dynamic simulation model which incorporated data on population recruitment and mortality, lamina growth and attrition, and interspecific competition for L. longicruris and L. digitata. The estimate for the total quantity of particulate material produced by this community at equilibrium is ≈6800 g∙m−2∙yr−1 (wet weight), or ≈408 g C∙m−2∙yr−1. The annual productivity to standing crop ratio (P:S) was determined to be ≈2.1:1. The productivity estimate for this community at equilibrium is considerably lower than a widely cited previous estimate for Laminaria productivity in Nova Scotia, which placed the seaweed zone amongst the most productive plant communities known. An evaluation of the methodology yielding this estimate has indicated that inaccurate estimates of population age structure and mortality have possibly resulted in a significant overestimation of particulate productivity.