Biology of the salema, Sarpa salpa (L. 1758) (Pisces, Sparidae) from the middle-eastern Adriatic

Salema Sarpa salpa (Linnaeus, 1758), were caught in the middle-eastern Adriatic Sea from August to November 2004. Length range of the samples was between 10.3 and 43.9 cm, with mean values of 25.5 cm in males, 32.6 cm in females, and 11.4 and 20.2cm in immature and hermaphrodite specimens, respectively. Sex ratio (males : females) was 3.1 : 1. Males were observed up to 37 cm length. Hermaphrodites showed lengths between 18 and 21 cm. The species was characterized by protandric hermaphroditism. Size at sexual maturity was 20.6 cm (2 years old) for males. Total length-total weight relationship for the entire population is described by the parameters a  = 0.00893, and b  = 3.1055. Otolith age readings showed that the population consisted of 15 age groups (1–15 years), including a very high proportion of individuals 1–7 years old. The von Bertalanffy growth parameters were L _∞ = 33.11cm, k  = 0.514, and t ₀ = −0.392 years for males and L _∞ = 40.85cm, k  = 0.179, and t ₀ = −2.606 years for females. Survival rate of females ( S  = 0.870) was much greater than for males ( S  = 0.769).     

Application of the chloroform fumigation-incubation method to the estimation of soil microbial biomass in burned and unburned Japanese red pine forests

Abstract Estimation of soil microbial biomass in burned and unburned Japanese red pine forests was attempted using the chloroform fumigation-incubation method. As the amount of CO₂-C evolved from the fumigated soil for 10–20 days after fumigation (designated as F') was always lower than that from the unfumigated soil during the same period (UF'), the formula, microbial biomass-C(M) = the amount of CO₂-C evolved from the fumigated soil for 0–10 days after fumigation, F) − F'/ k _c, was proposed instead of Jenkinson's conventional formula, M = (F − UF')/ k _c. The k _c value was also determined as 0.30 using 3 fungal and 3 bacterial cultured species as internal standards. Microbial biomass-C calculated by (F − F')/0.30 decreased with soil depth at both the burned (Nenoura, 3.5 years after fire) and unburned (Ato) sites, showing the significant correlation with the decrease of soil respiration and organic C content along soil depth. Microbial biomass-C in the 0–2 cm soil layer at the burned site at Nenoura was 130 mg/100 g dry soil and those in the HF horizon and 0–2 cm soil layer at the unburned site at Ato were 686 and 146 mg/100 g dry soil, respectively.     

Differences in clinical manifestations of influenza-associated encephalopathy by age

Data from patients in Japan was analyzed to examine the age distribution and differences by age in the clinical manifestations of influenza-associated encephalopathy. Between 1998 and 2002, 472 cases of influenza-associated encephalopathy in patients aged 15 years or younger were reported to the Collaborative Study Group on Influenza-Associated Encephalopathy. These cases were divided into two groups by age: 0–5 and 6–15 years. The differences between the groups were estimated based on the data for those aged 0–5 years, and the odds ratios and 95% confidence intervals calculated. Distribution was inversely correlated with age, with a peak at 1–2 years old. In comparison with patients aged 0–5, those aged 6–15 years had a significantly greater incidence of type B infection, lower frequency of convulsions, higher frequency of loss of consciousness and altered consciousness as the initial neurological symptom, lower serum transaminase levels, lower frequency of low-density area for brain CT upon admission, and lower incidence of sequelae. Our analysis indicates that the clinical course, laboratory data, and brain imaging findings of influenza-associated encephalopathy exhibits patterns that vary with age.     

Wood decomposition in an abandoned beech and oak coppiced woodland in SE England

The rate of litter decomposition is often expressed as a constant decay rate (k; g g⁻¹ yr⁻¹) or as the time required for a certain percentage (often 95% and estimated as 3/k) of it to decompose (termed turnover time). Estimates of k may be obtained by determining the weight loss of litter in the field and also by assuming a steady state and obtaining the ratio of litter input: standing crop. Both methods were used to estimate decay rate and turnover times for beech and oak branches and twigs decomposing on the forest floor and these were critically evaluated.
Considerable variation, ranging between 1.8–144.5 yr, was found between the 95% turnover time estimates of various size components of the two species, obtained from woodfall and standing crop data. Likewise variation in decay rate of 2–2.5 cm diameter beech branches, estimated from field experiments, was large both between and within groups of branches categorised according to initial state of decay and presence or absence of bark. The mean annual decay rate for the various categories ranged between k = 0.165-0.452 g g⁻¹yr⁻¹. Branches without bark generally decomposed more slowly than those with bark. Beech twig (<0.5 cm diameter) decomposition rates, from field experiments, ranged between k = 0.149-0.220 g g⁻¹yr⁻¹ and variation was relatively low compared with that of branches. No significant differences (P<0.05)were detected between twig decomposition rates obtained from experiments initiated at different seasons although there was a slight decline in decay rate in winter months. Twig and branch decomposition rates fell within the range found in the few other comparable studies.     

Pools as refugia for brown trout during two summer droughts: trout responses to thermal and oxygen stress

In non–drought years (1977, 1985), temperatures and oxygen concentrations from 1 to 14 July at the deepest point in each of five pools in Wilfin Beck were similar with ranges of 12–18° C and 7·8–9·8 mg l^–1. Trout Salmo trutta were present in all pools. In drought years (1976, 1983), temperature increased and oxygen concentration decreased as pool size decreased. In the two smallest pools, they were outside the thermal and oxygen limits for trout (ranges for both pools 24–29° C, 1·2–2·5 mg l^–1), and trout were absent. Values in a medium–sized pool were close to the incipient lethal levels and a few juvenile trout were present in both drought years. The lowest temperatures and highest oxygen concentrations were recorded in the two largest pools (ranges 20–25° C, 3·6–4·8 mg l^–1) and trout of all ages (0+ to adults) were present in both drought years. In these two pools, both temperature and oxygen concentration decreased from the surface to the deepest point in the pool. Trout preferred lower temperatures near the pool bottom rather than higher oxygen concentrations near the surface, but some fish moved towards the surface at night when the pool cooled slightly. These field results were discussed in relation to lethal values recorded for brown trout in the laboratory, and there was general agreement between field and laboratory values. Trout in the drought years occurred at temperatures close to, or below, the incipient lethal value of 24·7° C (+0·5) and also at the highest oxygen concentrations, but only when these were at temperatures below the incipient lethal value.     

ASSESSING KILLER WHALE PREDATION ON STELLER SEA LIONS FROM FIELD OBSERVATIONS IN KENAI FJORDS, ALASKA

The behavioral and predatory patterns of Gulf of Alaska (GOA) transient killer whales ( Orcinus orca ) were studied between 2000 and 2005 using remote video and vessel-based observations near the Chiswell Island Steller sea lion ( Eumetopias jubatus ) rookery and in the broader Kenai Fjords (KF) region of the northern GOA. GOA transient killer whales were observed on 118 d over the 6-yr period; the median group size was two (range: 1–9). Nine predation events were observed from vessels and an additional sixteen were inferred from remote video studies; all involved Steller sea lions. Estimates from field observations suggest that fifty-nine sea lions were consumed over the summer seasons of 2002–2005; whereas estimates based on published caloric requirements of transient killer whales would suggest a loss of 103 sea lions over the same time period. GOA transients spent a large proportion (43%) of their time resting which may be a strategy for conserving energy. Predation on sea lion pups at the Chiswell Island rookery was greatest during years when a single killer whale was foraging alone and when a 1.5-yr-old calf was evidently being trained to handle prey. Predation on pups was low during years when killer whales were foraging in groups and were observed and presumed to be taking mostly juvenile sea lions. Our study suggests that GOA transients are having a minor effect on the recovery of Steller sea lions in the GOA.     

Biology of the annular seabream, Diplodus annularis (Sparidae), in coastal waters of the Canary Islands

The biology of the Canary Islands annular seabream Diplodus annularis (Linnaeus 1758) was studied from samples collected between January and December 1998. Fish ranged from 82 to 209 mm total length in size and from 8.7 to 137.1 g in weight. The mean length showed an increase with increasing water depth. Males showed a negative allometric growth and females isometric growth. The species was characterized by protandric hermaphroditism. The overall sex ratio was unbalanced in favour of males (1 : 0.79). The reproductive season extended from January to May, with a peak in spawning activity in March–April. Males reached maturity at a smaller length (103 mm, 1-year-old) than females (128 mm, 2-year-old). Fish aged 0–6 years were found. The von Bertalanffy growth parameters for all individuals were: L_∞=247.9 mm, k=0.268 years^–1, and t₀=–0.879 years.     

Age, growth, reproduction and mortality of the striped seabream, Lithognathus mormyrus (Pisces, Sparidae), off the Canary Islands (Central-east Atlantic)

Striped seabream, Lithognathus mormyrus L. (n=731) caught off the Canary Islands from January 1999 to June 2000 were studied. Fish ranged in size from 113 to 372 mm total length, weighing from 21.1 to 748.2 g total weight. Weight increased allometrically with size (b=2.9071). Fish age was 0–10-years-old. Growth was relatively slow (k=0.88 years⁻¹), with females growing at a slightly faster rate than males. The species displayed protandric hermaphroditism. Male : female ratio was unbalanced in favour of males (1 : 0.85). Males predominated in smaller sizes, females in larger sizes, and intersexual individuals were in intermediate sizes. The reproductive season extended from June to December, with a peak in spawning activity in August–September. Males reached maturity at 207 mm (2 years) and females at 246 mm (3 years). The real value of instantaneous rate of natural mortality was between 0.30 and 0.45 years⁻¹.     

Seroepidemiology of Helicobacter pylori infection in Greece

Abstract Helicobacter pylori infection is strongly associated with chronic gastritis and peptic ulceration. As the prevalence of H. pylrori infection in southern European populations is not known, a serological survey of 1069 samples from three different age groups in the Greek population was carried out with an enzyme-linked immunosorbent assay (ELISA) for antibodies to these bacteria. The antigen was an ultracentrifuged supernate of whole cell sonicates of 5 isolates of H. pylori assessed by electrophoresis and by immunoblotting with negative and positive sera. The sensitivity of the test was 97.43% and the specificity 100% for IgG antibodies; IgA and IgM antibodies to the antigen preparation were not found. Antibodies to H. pylori were detected among 39.49% of children aged 1–10 years, 67.1% of recruits (20–27 years) and 70% of blood donors (20–50 years). The prevalence of antibodies did not differ iwth sex in each of the age groups. The proportion of individuals with antibodies to H. pylori was higher in the younger age groups than those reported for similar age groups in Western Europe.     

Spatial structure in length at age of cod in the Barents Sea

Cod Gadus morhua population in the Barents Sea was found to be spatially structured with regard to length-at-age. Results were based on data collected during research surveys in the Barents Sea between 1982 and 1997. The identified spatial structure was most pronounced for age groups 2–4 years and decreased for the older age groups with higher potential for migration. A positive linear correlation between mean length-at-age and mean geographical temperature was established for age groups 2–4 years. This correlation was shown to be strongest when based on mean temperatures during 3 year periods ending with the year of capture. The spatial structure in length-at-age was shown to follow the temperature gradient of the Barents Sea. A large part of the observed area effects could be explained by temperature variation between areas. Evidence is also presented which indicates that the predictability and sensitivity of the dependence of length-at-age on temperature increases under extreme environmental conditions, i.e. in the northern and eastern areas of the Barents Sea.     

Biology of the Dragonet, Callionymus kaianus moretonensis Johnson (Pisces:Callionymidae)

A collection in excess of 1000 specimens of Callionymus kaianus moretonensis, trawled off southern Queensland, afforded an opportunity to study various aspects of the biology of this species. It inhabits muddy bottoms at depths of 101–150 m off south-east Queensland between Noosa and Cape Moreton, Moreton Island. Penaeid prawns were the predominant food during all seasons and for all size groups. A great diversity of food items were ingested, especially in the pelecypod and gastropod categories. Factors influencing feeding and vulnerability of prey organisms are discussed. Of the 907 specimens that were sexed, 422 (46.7%) were males and 485 (53.3%) were females. C. k. moretonensis has a prolonged breeding period in which each female spawns a number of times. Only a few oocytes appear to be discharged at any one time from the ovary. Practically every stage of ovarian development was found in each ovary examined regardless of time of year. Oocyte diameter averaged 0.51 mm immediately prior to spawning and numbers of ova ranged from 1285 to 22,478. C. k. moretonensis may have either a benthic larvae or a short-lived planktonic one. Length-weight relationships are represented by the regressions, log W = -1 5.24 + 3.77 log L (males) and log W = -16.77 + 4.12 log L (females). Otoliths were used for age and growth determinations. C. k. moretonensis reaches age group IV+. Growth of males slightly exceeded that of females, with the greatest difference occurring between the third and fourth years of life. No evidence of high post-breeding mortality was found in spent males.     

Temporal variation in abundance, return rate and life histories of previously spawned Atlantic salmon in a large subarctic river

The 30 year time series analyses revealed large temporal variation in the return rates and a recent increase in abundance of previous spawning Atlantic salmon Salmo salar in the River Teno, northern Scandinavia. The mean proportion of repeat spawners was 7 and 4% in the total Atlantic salmon catch and 9 and 22% in multi‐sea‐winter (MSW) catch component for females and males, respectively. Previous spawners constituted on the average 7% of the catch in mass but up to 20%(31 t) and 30%(19 t) in 2003 and in 2004, respectively. In 1975–2000, the proportion of previous spawners varied between 1 and 6%(3–12% of MSW Atlantic salmon), whereas in 2001–2004, they accounted for 8–21%(16–35% of MSW Atlantic salmon) of the total Atlantic salmon catch. The number of previous spawners in the catch correlated significantly with the preceding numbers of respective 1–3 sea‐winter (SW) maiden Atlantic salmon 2 years earlier. The recent increase in the numbers of 1S1 and 2S1 (1 or 2 years at sea followed by first spawning and 1 year reconditioning period at sea) alternate spawning Atlantic salmon was a consequence of higher numbers of maiden 1SW and 2SW Atlantic salmon in the catches and increased sea temperatures. Similarly, the return rate of 1SW Atlantic salmon to second spawning has improved in recent years. Most previous spawners ascended and were captured early in the fishing season. The smolt and sea‐age combinations of repeat spawners comprised 68 age groups contributing with the annual mean of 15 age groups to the great diversity of the River Teno Atlantic salmon population complex.     

Estimating the invasion success of introduced plants

We present methods for estimating the base proportion of introduced alien species that will naturalize, and the distribution of time until naturalization occurs. The approach is Bayesian, incorporating prior estimates of the probability of naturalization and the time from introduction to naturalization. A worked example uses data on the introduction and time to recorded naturalization of woody perennials introduced to South Australia. Up until 2007, 188 of 2230 (8.4%) woody perennials listed in nursery catalogues between 1843 and 1985 were recorded as having naturalized. If prior information on naturalization rates from elsewhere is ignored, the available data suggest that the most likely proportion of introduced plants that will naturalize is large (0.93) though uncertain (95% CI 0.51–0.99), with the corresponding mean time to recorded naturalization being protracted (522 years) and similarly uncertain (95% CI 360–678 years). Alternatively, if informative prior estimates of both the naturalization probability and the time to recorded naturalization are incorporated, the most likely probability of naturalization is estimated to be 18.6% (95% CI 15.5–23.4%). For those plants that do naturalize, the most likely value for the mean time from importation to recorded naturalization is 149 years (95% CI 130–174 years). Our results illustrate the potentially long timescale of the naturalization process, and the challenges this presents for obtaining accurate estimates of naturalization parameters.     

Genetic diversity and effective size of the Atlantic salmon Salmo salar L. inhabiting the River Eo (Spain) following a stock collapse

Historic angling records suggest the occurrence of a drastic decline in the River Eo (Spain) Atlantic salmon population size during the past two decades, as a result of overexploitation and habitat deterioration. In recent years, the population has been apparently recovering, and the present study is aimed to report information on the level of genetic diversity and the effective size of the current population as these may have immediate consequences for its conservation. Eighty-six salmon from two temporal groups (1998–1999 and 2004–2006), representing three generations, were genotyped using a panel of eight microsatellites. Inspite of the recent decline in census numbers and the detection of the signs of a population bottleneck, the population exhibits a high level of genetic diversity, similar to that from other populations, and almost unchanged during the period of study [average allelic richness ( A ) = 14·0 and 13·9, and average heterozygosity ( H _e) = 0·843 and 0·851 in 1998–1999 and 2004–2006, respectively]. The effective population size ( N _e) estimated by two different temporal methods showed a consistent value around 80 salmon, whereas the estimates from the linkage disequilibrium (LD) method provided a value around 165 individuals for either sample. The recent growing number of salmon, as indicated by fisheries records, the relatively large estimates of the ratio N _e/ N (with range 0·23–0·44 for the temporal estimates and 0·31–0·59 for the LD estimates) and the high levels of diversity found suggest that the population has not been greatly affected by the historical census declines and can be expected to recover in the future.     

Aspects of the biology of Nezumia aequalis from the continental slope west of the British Isles

Nezumia aequalis is one of the most abundant fishes on the upper and middle continental slopes (500–1750 m depth zones) of the North-east Atlantic with a peak abundance of three to four individuals 1000 m⁻² swept area in the 750-m zone. Mean and modal size increased with depth, fish from the Rockall Trough (RT) being larger than those at equivalent depths in the Porcupine Seabight (PSB). Sex ratios were close to parity in all depth zones. Females grew larger than males. Head length to total length and to total weight did not differ significantly between sexes but RT fish were heavier at any given length than PSB fish. Serial batch spawning occurred over the first three quarters of the year. Ovaries contained five size groups of eggs, the three largest groups being vitelline and contributing 27% of the absolute individual fecundity which was positively correlated with body size and ranged from 9109 to 26 847. Age determined from sagittal otoliths ranged from 1 to 10 years, the ageing method being validated by a time-series study of the growing edge of otoliths. The von Bertalanffy growth parameter ( k ) was estimated at 0·175 and 0·216 from head length and otolith length, respectively.     

Resting and arecoline-stimulated brain metabolism and signaling involving arachidonic acid are altered in the cyclooxygenase-2 knockout mouse

Studies were performed to determine if cyclooxygenase (COX)-2 regulates muscarinic receptor-initiated signaling involving brain phospholipase A₂ (PLA₂) activation and arachidonic acid (AA; 20 : 4n-6) release. AA incorporation coefficients, k* (brain [1–¹⁴C]AA radioactivity/integrated plasma radioactivity), representing this signaling, were measured following the intravenous injection of [1–¹⁴C]AA using quantitative autoradiography, in each of 81 brain regions in unanesthetized COX-2 knockout (COX-2^–/–) and wild-type (COX-2^+/+) mice. Mice were administered arecoline (30 mg/kg i.p.), a non-specific muscarinic receptor agonist, or saline i.p. (baseline control). At baseline, COX-2^–/– compared with COX-2^+/+ mice had widespread and significant elevations of k*. Arecoline increased k* significantly in COX-2^+/+ mice compared with saline controls in 72 of 81 brain regions, but had no significant effect on k* in any region in COX-2^–/– mice. These findings, when related to net incorporation rates of AA from brain into plasma, demonstrate enhanced baseline brain metabolic loss of AA in COX-2^–/– compared with COX-2^+/+ mice, and an absence of a normal k* response to muscarinic receptor activation. This response likely reflects selective COX-2-mediated conversion of PLA₂-released AA to prostanoids.     

A biological analysis of eel catches, Anguilla anguilla L., from the lagoons of Lesina and Varano, Italy

A study of eel catches from Lesina (444 specimens) and Varano lagoons (325 specimens), in southern Adriatic, Italy, was made. Male silver eels in Lesina ranged from 33.4–51.5 cm in length, with a mean of 42.6 cm; from 50–240 g in weight, with a mean of 141 g and were 1.5–6.5 years old with a mean of 2.5 years. The average length of male silver eels in Varano lagoon was 40.5 cm (range 31–48.5 cm); the average weight was 122 g (range 80–220 g)and a mean age of 2.6 years (range 1.5–7.5 years).
The females are bigger, heavier and older than the males with, in Lesina, a mean length of 61 cm (range 50.9–74.3 cm), a mean weight of 438 g (range 240–730 g) and a mean age of 3.4 years (range 1.5–6.5). The average length of Varano female silver eels was 58 cm (range 50.8–72.5 cm), and the average weight was 383 g (range 225–840 g). They were 1.5–7.5 years old, with an average of 3.8 years. Female silver eels were only 20% of the population at Lesina and 10% at Varano.
In comparison with the silver eel populations of the North Adriatic lagoons, the North Sea or the Atlantic Ocean, the silver eels of Lesina and Varano show a greater growth rate, are younger and have a sex ratio in favour of the males.
The water temperature, higher than in other countries, could be an important factor affecting the differences in age and growth rates between Lesina and Varano silver eels and those of other waters.     

Degradation of Dynorphin-Related Peptides by the Puromycin-Sensitive Aminopeptidase and Aminopeptidase M

Abstract: The degradation of dynorphin-related peptides by the puromycin-sensitive aminopeptidase and aminopeptidase M was examined using these peptides as alternate substrate inhibitors. K _i determinations showed that both aminopeptidases exhibit a higher affinity for longer dynorphin-related peptides, i.e., K _i for dynorphin A-17 = 23–30 n M with the K _i increasing to 25–50 µ M for the enkephalin pentapeptides. Binding appears dependent not only on peptide length, but also on its sequence. With aminopeptidase M, as the peptide size increases from five to 10 amino acids, k _cat remains relatively constant; however, as the peptide size increases beyond a decapeptide, k _cat decreases significantly. With the puromycin-sensitive aminopeptidase, similar results were obtained except that k _cat was greatest for the pentapeptide. Thus, if one considers k _cat/ K _m as the relevant kinetic constant for estimating in vivo peptide hydrolysis, these results are consistent with the involvement of aminopeptidase M and the puromycin-sensitive aminopeptidase in the degradation of extended dynorphin-related peptides.     

A Robust DNA Amplification Fingerprinting System Applied to Analysis of Genetic Variation Within Fusarium oxysporum f.sp. cubense

Genetic variation among isolates of F. oxysporum f.sp. cubense (Foc) was analysed using a DNA amplification fingerprinting (DAF) system modified to improve reproducibility and transportability. This analysis was done after determining the widest tolerance range (or 'window of reproducibility') for each component in amplification reaction. Reproducible polymerase chain reactions (PCRs) were achieved with between 25 and 250 ng of template DNA, 9–15 μM primer, 4–6 mM MgCl² and 2–4 units of Stoffel Fragment enzyme. For experimental work we used the middle value of these ranges which allowed at least 20% error tolerance for each component. Similarly, thermocycling and electrophoresis conditions were also improved. Manual scoring of the DNA fingerprints was compared to analysis of scanned gel images using the Gel Compar program (Applied Maths, Kortrijk, Belgium). The data were clustered by unweighted pair group method analysis (UPGMA) based on the Jaccard similarity coefficient. Isolates of Foc representing all known vegetative compatibility groups (VCGs) were examined and the genetic relationships between the VCGs were determined. Isolates of Foc were divided into two major groups with 30% genetic similarity. These optimized DNA amplification, thermocycling, and electrophoresis conditions were suitable for analysis of other organisms and should be applicable to other techniques that use arbitrary primers such as random amplified polymorphic DNA (RAPD) and arbitrarily primed-PCR (AP-PCR).     

Heat resistance of Campylobacter and Yersinia strains by three methods

Two methods of determining the heat resistance of bacteria, a glass cup and a test tube method, were compared with a method using capillary tubes. Three strains of Yersinia enterocolitica , one of Campylobacter jejuni and two of C. coli were tested in physiological saline. The differences between the results obtained by the glass cup method and the reference method were not statistically significant for five strains and were small also for the other, a Yersinia strain. D values obtained by the glass cup method at 58, 60 and 62°C were 1.4–1.8, 0.40–0.51 and 0.15–0.19 min ( z values 4.00–4.52°C) for the Yersinia strains, and 0.42, 0.13 and 0.07 min ( z value 5.07°C) for one C. coli strain. For the other Campylobacter strains, D values of 0.71–0.78, 0.24–0.28 and 0.12–0.14 min ( z values 4.94 and 5.60°C) were recorded at 56, 58 and 60°C. D values obtained at 60°C by the test tube method were 2.7–5.0 min and were considered to be unrealistic.