Mortality of Baltic sea trout (Salmo trutta) after release from gillnets

We explore the mortality rate of disentangled sea trout in whitefish fishery using gillnets with a 35–43 mm bar length. The study was conducted during the main fishing seasons in the Gulf of Bothnia in the northern Baltic Sea. Overall 59.5% of the sea trout were alive at the end of a 2–7 day observation period following release from the gillnets. Altogether, 12.1% of the captured fish were found dead in gillnets and 28.4% died due to injuries during an extended observation period. The average length of the captured sea trout was 435 mm, indicating that the majority were spending their first or second year at sea. The proportion of the survived and not injured (no observed damage) fish was highest in larger fish, >450 mm. The injured and not injured fish died equally frequently. Post capture survival was not connected to the removal time from gillnets or type of observed injuries but to the type of entanglement. Most of the fish were entangled by a mesh around the body, which caused extensive scale loss and open sores on the skin. The smallest fish may have had internal wounds that were not registered in this study. These results can be used in fisheries management to estimate the mortality of multi‐species gillnet fishing to sea trout populations in relation to management actions.     

多网目单层和三重组合刺网在岩礁和沙地生境中的鱼类采集效果比较

为了解多网目单层组合刺网(MGN)和三重组合刺网(MTN)在近岸软相和硬相生境中的鱼类采集效果,于2011年10月选择枸杞岛沙地(SB)和岩礁(RR)生境为研究对象,从种类组成、捕获方式、优势种渔获率、多样性和群落格局上对MGN和MTN在两种生境中的鱼类采集效果进行了比较.结果表明:SB中MTN比MGN多采集鱼类5种,RR中相应多采集鱼类8种;SB中的MGN采获优势种为青鳞小沙丁鱼(Sardinella zunasi)和小黄鱼(Larimichthys polyactis),MTN增加了日本须鳎(Paraplagusia japonica);RR中的MTN仅采获褐菖鲉(Sebastiscus marmoratus)和斑头鱼(Hexagrammos agrammus)两种优势种,但MGN相应多出青鳞小沙丁鱼和小黄鱼;两生境中MGN的捕获方式均以契入为主,而MTN的渔获个体中其他捕获方式的比例明显增加;MGN对两生境近底层小黄鱼和中上层青鳞小沙丁鱼的捕获率显著高于MTN,但对褐菖鲉、斑头鱼以及日本须鳎等底层鱼类的捕获率上,MGN要低于MTN;SB中基于MTN的多样性指标均显著大于MGN,而RR中两者之间的各指标并无显著差异;两生境中MGN和MTN所呈现的群落格局均存在显著差异.在进行刺网采样时,需依据研究目标应用适宜的网具和方法,以最大限度地了解鱼类组成的真实情况.     

Origins of the southeastern Australian vegetation

Australia is an ancient continent with an interesting geological history that includes a recent major shift in its position, both globally and compared with neighbouring land masses. This has led to a great deal of confusion over many years about the origins of the Australian biomes. The plant fossil record is now clarifying this, and it is clear that the ancient Gondwanan rainforests that covered Australia while it was still part of that supercontinent contained many of the elements of the modern vegetation. However, major climatic sifting, along with responses to other factors, including soil nutrient levels, disturbance regimes, atmospheric CO2 levels, fire frequency and intensity, glaciations and the arrival of humans, have had profound impacts on the Australian vegetation, which today reflects the sum of all these factors and more. The origins of Australian vegetation and its present-day management cannot be properly understood without an appreciation of this vast history, and the fossil record has a vital role to play in maintaining the health of this continent's vegetation into the future.     

Molecular identification of co-occurring Cortinarius and Dermocybe species from southeastern Australian sclerophyll forests

 The ability of restriction fragment length polymorphism (RFLP) analysis of the rDNA internal transcribed spacer (ITS) region to discriminate 10 co-occurring Cortinarius and Dermocybe species at a southeastern Australian sclerophyll forest site was assessed. Using the basidiomycete-specific primers ITS1F and ITS4B, some taxa were separated on the basis of individual RFLP patterns derived using the restriction endonucleases Hae III or Hinf I. Combined data from both endonucleases were, however, required to separate all taxa [Dermocybe austro-veneta Clel. (Moser & Horak), C. rotundisporus Clel. & Cheel, C. archeri Berk., C. sinapicolor Clel., C. violaceus (L.: Fr.) S.F.Gray, C. radicatus Clel. and four morphologically-distinct, but unidentified Cortinarius spp.]. ITS sequence comparisons confirmed that D. austro-veneta belongs in Dermocybe, that C. rotundisporus is correctly placed in subgenus Phlegmacium, and suggest that Australian C. violaceus collections are not conspecific with northern hemisphere C. violaceus. Accepted: 4 March 1999     

Population dynamics of two suspension-feeding bivalves on a sheltered beach in southeastern Brazil

The population biology and secondary production of the bivalves Anomalocardia brasiliana (Gmelin, 1791) and Diplodonta punctata (Say, 1822) were studied on a sheltered beach on the southeast coast of Brazil (Flexeiras Beach) between December 2006 and February 2009. Six transects were established perpendicular to the shoreline. Along each transect, sampling units (SUs) were extracted every 3?m, with a 0.04?m² metal sampler and to a depth of 25?cm, from the base of the boulder wall until 9?m below the waterline during low tide. The abundances of A. brasiliana and D. punctata were inversely correlated over time. The populations differed in several aspects: (1) A. brasiliana occupied mainly the upper levels, whereas D. punctata occupied the lower level of the beach; (2) total abundance, growth rate, and production were higher for A. brasiliana; and (3) mortality and turnover rate were higher for D. punctata. The differences in growth, mortality, and production parameters may be associated with a difference in the species’ abilities to exploit resources.     

Nitrogen release from surface sand of a high energy beach along the southeastern coast of North Carolina,USA

This study examined changes in dissolved organic nitrogen (DON) and dissolved inorganic nitrogen (DIN) in coastal seawater after exposure to sand along a high energy beach face over an annual cycle between April 2004 and July 2005. Dissolved organic nitrogen, NO₃ ⁻, and NH₄ ⁺ were released from sand to seawater in laboratory incubation experiments clearly demonstrating that they are a potential source of N to underlying groundwater or coastal seawater. DON increases in seawater, after exposure to surface sands in laboratory experiments, were positively correlated with in situ water column DON concentrations measured at the same time as sand collection. Increase in NO₃ ⁻ and NH₄ ⁺ were not correlated with their in situ concentrations. This suggests that DON released from beach sands is relatively more recalcitrant while NO₃ ⁻ and NH₄ ⁺ are utilized rapidly in the coastal ocean. The release of N was seasonal with carbon to nitrogen ratios indicating that recent primary productivity was responsible for the largest fluxes in summer while more degraded humic material contributed to lower fluxes in winter. Fluxes of total dissolved nitrogen (DON and DIN) from surface sand (2.1 × 10⁻⁴ mol m⁻² h⁻¹) were similar to that of groundwater and more than an order of magnitude larger than rain deposition indicating the potential importance of surface sand derived nitrogen to the coastal zone with a corresponding impact on primary productivity.     

Estimating tree and stand sapwood area in spatially heterogeneous southeastern Australian forests

Aims Natural and anthropogenic changes in forests can have important influences on transpiration and water production. Understanding the effects of increasing disturbances, due for example to climate change and forest harvesting, requires detailed information on how forest density and structural attributes relate to transpiration. Mean annual transpiration of eucalypt forest communities is often strongly correlated with total cross-sectional sapwood area. Our aim was to test an efficient method for estimating sapwood area at 1.3 m height (SA 1.3) in a large number of trees to understand the spatial heterogeneity of tree and stand sapwood area within and between forest communities, and develop allometric relationships that predict SA 1.3 with forest inventory data. We also apply tree competition models to determine the degree to which the relationship between SA 1.3 and tree basal area at 1.3 m height (BA 1.3) is influenced by competition.Methods We visited 25 recently harvested southeastern Australian forest sites consisting of 1379 trees and 5 Eucalyptus species to evaluate a new efficient data collection method for estimating SA 1.3 with tree taper and stump dimensions data using mixed effects models. The locations of 784 stumps within one 5-ha site were accurately mapped using an unmanned aerial vehicle (UAV), and four distance-dependent tree competition models were applied across the site to explain within-stand variation in the ratio of SA 1.3 to BA 1.3. Data from 24 additional sites, consisting of ten 15 m radial plots per site, were used to analyse within-site variation in R Ha (the ratio of stand sapwood area SA Ha to stand basal area BA Ha). The radial plots were merged within each site to evaluate between-site variations in R Ha across the landscape. For predicting SA Ha with forest inventory data, we computed the relationship between SA Ha and a new index of total stem perimeter per hectare, defined as ? B A H a N T, where N T is tree stocking density.Important findings Our 1379 measured stems represent the most comprehensive measure of sapwood area, surpassing the 757 measured stems in native eucalypt forests published in literature. The species-specific R Ha varied considerably across sites and therefore extrapolating SA Ha with spatially distributed BA Ha maps and a generalized R Ha would introduce local uncertainty. We found that the species-specific stem perimeter index was more effective at capturing variability in SA Ha across the landscape using forest composition, structure and density data (R 2 : 0.72–0.77). The strong correlation between tree SA 1.3 and BA 1.3 improved slightly using tree competition models (R 2 increased from 0.86 to 0.88). Relating SA Ha to routinely measured forest inventory attributes within permanent plots and Light Detection and Ranging (LiDAR) data may provide opportunities to map forest water use in time and space across large areas disturbed by wildfire and logging.     

Population genetics and conservation of the threatened southeastern beach mouse (Peromyscus polionotus niveiventris): subspecies and evolutionary units

We investigated genetic diversity within the southeastern beach mouse (SEBM-Peromyscus polionotus niveiventris) and also tested the hypothesis that the subspecies recognition of P.p. niveiventris, based on size and color differences, is congruent with this taxon representing a discrete evolutionary lineage. We used ten polymorphic microsatellite loci and mitochondrial cytochrome-b gene DNA sequences to investigate genetic diversity and population structure within the SEBM, and to determine the level of divergence between the SEBM and the nearest known inland subspecies of the oldfield mouse (Peromyscus polionotus rhoadsi). Moderate genetic distances were observed between the SEBM and the inland oldfield mouse based on microsatellite data, with F _ST values ranging from 0.11 to 0.22 between these taxa. Additionally, mitochondrial DNA haplotypes of the SEBM formed a distinct monophyletic group relative to haplotypes sampled from P. p. rhoadsi. Based on previous estimates of rates of mitochondrial DNA evolution in rodents, we inferred that Pleistocene sea-level fluctuations are likely responsible for the historical isolation of the SEBM lineage from mainland P. polionotus. Our data demonstrate the genetic distinctiveness of the SEBM, justifying the current subspecies designation for the SEBM and its continued protection under the United States Endangered Species Act. We classify the Cape Canaveral and Smyrna Dunes Park populations of SEBM as a single evolutionary significant unit. The two known extant allopatric populations of the SEBM showed some differentiation in microsatellite frequencies and were moderately reciprocally distinguishable based on assignment to distinct genetic clusters by a Bayesian admixture procedure. These results justify the classification of these two extant SEBM populations as distinct management units that should be independent targets of management and conservation attention.     

Ichnology of Lower Jurassic beach deposits in the Shemshak Formation at Shahmirzad,southeastern Alborz Mountains,Iran

A 19 m thick package of well-sorted lowermost Jurassic (Hettangian-Lower Sinemurian?) sandstones within the Shemshak Formation of the southeastern Alborz Mountains displays features characteristic of foreshore to upper shoreface environments such as tabular bedding, low-angle lamination, trough cross-stratification, parting lineation, and oscillation ripples. In contrast to most other beach successions recorded in the literature the sandstones contain a trace fossil assemblage characterised by low abundance but comparatively high diversity. The assemblage, comprising 14 ichnotaxa, is dominated by Palaeophycus heberti, Rhizocorallium irregulare, Gyrochorte comosa, and Parahaentzschelinia surlyki. Contrary to predictions, which assume a dominance of suspension-feeders in such high-energy environments, the trace fossil assemblage represents a variety of ethological groups ranging from suspension-feeders to deposit-feeders, detritus-feeders, scavengers, and a possible trap constructor (Ctenopholeus), whereby deposit-feeders predominate. This anomaly is explained by a high amount of organic detritus in the sediment, indicated by abundant plant material, and a position of the beach in the vicinity of a river mouth.     

Catch and discards from experimental trawl and longline fishing in the deep water of the Rockall Trough

Comparative bottom trawl and longline surveys were carried out on two chartered commercial fishing vessels in the deep waters (350-1300 m) of the Rockall Trough, an area subjected to heavy commercial exploitation. The species composition, catch rates and length distributions from each survey were very different and reflected the fundamental difference in the two types of fishing operations. Bottom-trawled catches produced greater species diversity and higher discard rates. Longline catches produced larger specimens of teleost fish and were dominated by squalid shark. Trawl discards, expressed as kgs of discards per tonne of roundnose grenadier Coryphaenoides rupestris landed, were calculated for a broad range of the most abundant species taken in the catch. First estimates of total international discarding from deep-water trawling operations in the Rockall Trough area (7530 tonnes; 26.5 million individuals) were made by raising the discard rates using international grenadier landings for 1995. The outlook for the continued exploitation of the deep-water fish resource in the Rockall Trough and possible management options are discussed.     

Coexistence of a locally undifferentiated foraging guild: avian snatchers in a southeastern Australian forest

Three species of sexually dichromatic, insectivorous birds (Golden Whistler, Pachycephala pectoralis; Rufous Whistler, Pa. rufiventris; Rose Robin, Petroica rosea) employ a characteristic foraging manoeuvre (snatching or sally‐striking) disproportionately often, leading several studies to group them together in one foraging guild. The three species synchronously co‐occupy an extensive eucalypt forest east of Melbourne, Australia (Olinda State Forest). All assemble in relatively high densities in late winter and through spring and early summer to breed. Log‐linear modelling of use of foraging techniques, substrate, plant species and heights within the forest indicate that all six species–gender groups virtually do not differ from one another: a situation in which very similar species coexist at high densities. The results are considered in the context of interspecific competition among ecologically similar species and it is suggested how such a situation might arise and be sustained. The absence of gender‐specific differentiation within species is also addressed.     

Traditional and Emerging Lifestyle Risk Behaviors and All-Cause Mortality in Middle-Aged and Older Adults: Evidence from a Large Population-Based Australian Cohort

Background

Lifestyle risk behaviors are responsible for a large proportion of disease burden worldwide. Behavioral risk factors, such as smoking, poor diet, and physical inactivity, tend to cluster within populations and may have synergistic effects on health. As evidence continues to accumulate on emerging lifestyle risk factors, such as prolonged sitting and unhealthy sleep patterns, incorporating these new risk factors will provide clinically relevant information on combinations of lifestyle risk factors.

Methods and Findings

Using data from a large Australian cohort of middle-aged and older adults, this is the first study to our knowledge to examine a lifestyle risk index incorporating sedentary behavior and sleep in relation to all-cause mortality. Baseline data (February 2006– April 2009) were linked to mortality registration data until June 15, 2014. Smoking, high alcohol intake, poor diet, physical inactivity, prolonged sitting, and unhealthy (short/long) sleep duration were measured by questionnaires and summed into an index score. Cox proportional hazards analysis was used with the index score and each unique risk combination as exposure variables, adjusted for socio-demographic characteristics.During 6 y of follow-up of 231,048 participants for 1,409,591 person-years, 15,635 deaths were registered. Of all participants, 31.2%, 36.9%, 21.4%, and 10.6% reported 0, 1, 2, and 3+ risk factors, respectively. There was a strong relationship between the lifestyle risk index score and all-cause mortality. The index score had good predictive validity (c index = 0.763), and the partial population attributable risk was 31.3%. Out of all 96 possible risk combinations, the 30 most commonly occurring combinations accounted for more than 90% of the participants. Among those, combinations involving physical inactivity, prolonged sitting, and/or long sleep duration and combinations involving smoking and high alcohol intake had the strongest associations with all-cause mortality. Limitations of the study include self-reported and under-specified measures, dichotomized risk scores, lack of long-term patterns of lifestyle behaviors, and lack of cause-specific mortality data.

Conclusions

Adherence to healthy lifestyle behaviors could reduce the risk for death from all causes. Specific combinations of lifestyle risk behaviors may be more harmful than others, suggesting synergistic relationships among risk factors.     

Mortality of key fish species released by recreational anglers in an Australian estuary

A field experiment was done to quantify the mortality of fish released during a recreational angling tournament in Botany Bay, Australia. Participating boat-based anglers were divided into two groups, each representing different typical catch-and-release events. The first group (termed the ‘live weigh-in group’) retained the largest two individuals of 4 species (dusky flathead, Platycephalus fuscus, yellowfin bream, Acanthopagrus australis, sand whiting, Sillago ciliata, and trevally, Pseudocaranx dentex) in onboard holding tanks and then presented these to researchers at designated weigh-in times and stations. Gear, operational and handling data were collected before 125 fish were tagged using plastic t-bar tags, returned to the anglers and then released into two sea cages. The second group (termed the ‘immediate-release group’) immediately released 224 fish into two sea cages, after they were tagged and relevant data recorded by onboard observers. This group represented those fish routinely discarded (i) as part of catch-and-immediate-release tournaments and/or (ii) due to minimum legal sizes and/or personal quotas. Appropriate species and numbers of ‘control’ fish were seined and placed into two sea cages. All fish were monitored for mortalities over 10 days. Dusky flathead, yellowfin bream, trevally and snapper, Pagrus auratus accounted for more than 85% of the total catch. Their adjusted mortalities ranged between 0% and 36.6%. Irrespective of the treatment, most yellowfin bream and snapper deaths occurred within 3 h of being hooked and released into the cages, while trevally and dusky flathead showed a delayed mortality over 4 days. Owing to confounding effects due to their confinement, dusky flathead were excluded from further analyses. Anatomical hook location and the time between capture and release were significant predictors of mortality for yellowfin bream and trevally, respectively (p < 0.01), but none of the various gear, operational or handling factors examined were significant for snapper (p > 0.05). The results are discussed in terms of species-specific variabilities in mortalities, their causal effects and better management of catch-and-release events.     

Ordovician chitinozoans and acritarchs from southern and southeastern Turkey

Revision of the lithostratigraphy of Ordovician deposits in southern and southeastern Turkey led to a re-evaluation of the age assignments of formations identified in the subsurface and at outcrop. Previous datings were based on macrofauna (mainly trilobites and graptolites). The present paper focuses exclusively on organic-walled microfossils (chitinozoans and acritarchs), which provide numerous chronostratigraphical improvements, especially in successions barren or poor in macrofossils. Close to 200 samples were collected in the Taurus chain (i.e. from Kemer, Seydisehir, Ovacik, Kozan, to Sariz regions in southern Turkey) and in the Border Folds (Mardin and Hakkari regions), usually regarded as part of the Arabian Plate in palaeogeographical reconstructions. Many samples are productive and yield chitinozoans and/or acritarchs of extremely variable preservation, depending on their geographical and geological location. In the Taurus chain, the material is “coalified” and frequently fragmented whereas, in the Border Folds, maturation of the organic matter is much lower and preservation of the microfossils is good to excellent. Several Ordovician chitinozoan biozones (northern Gondwana zonation) as well as diagnostic acritarch assemblages are identified in southern and southeastern Turkey. These Ordovician formations are assigned here to the new global stages of the Ordovician chronostratigraphical scale. The Seydisehir (upper part), Sobova, and Kilgen Lake (lower part) formations are referred to the Darriwilian. The Kilgen Lake (upper part), Sort Tepe, and Bedinan formations are attributed to the Sandbian and to the Katian, and the Halevikdere Formation (glacio-marine part) is assigned to the Hirnantian. Reworking of Early Ordovician acritarchs is documented in pre-glacial and in glacial Late Ordovician deposits. They indicate that active erosive processes occurred during the Middle and Late Ordovician sedimentation. The organic-walled microfossils recorded in the Ordovician of south and southeastern Turkey belong to the northern Gondwana realm. Interestingly however, some Baltoscandian influences are noted in the Border Folds during Early Late Ordovician.     

The relationship between invertebrate assemblages and available food at forest and pasture sites in three southeastern Australian streams

1. Levels of ash-free dry matter (AFDM) and chlorophyll a in epilithon, benthic participate organic matter (BPOM), invertebrate assemblage composition, and biomass of functional feeding groups were compared in winter and summer at forest and pasture sites in three Victorian streams. 2. Chlorophyll a concentrations of epilithon were significantly higher at pasture than forest sites in winter but not in summer while BPOM was not significantly greater at forest sites in either season. Epilithic biomass as AFDM did not show consistent differences between land uses or seasons. 3. Total biomass of invertebrates did not differ between forest and pasture sites but the biomass of shredders was significantly higher, and that of grazers significantly lower, at forest than pasture sites. A site shaded with an artificial canopy behaved as a forest site for grazers but as a pasture site for shredders. 4. Cluster analyses of invertebrate assemblages grouped pasture sites with forest sites on the same stream at the same season, indicating that assemblage composition was less influenced by land-use differences than by between-stream and seasonal differences. 5. Biomass of functional feeding groups appeared to be a more sensitive indicator of invertebrate assemblage response to land-use alteration than either species diversity/ richness measures, or multivariate assemblage composition measures.     

Sanitary quality of marine sediments and sands from an Italian beach

Microbiological surveys were carried out on marine sands and sediments collected at a sandy beach along a coastal area close to Rome, Italy. Low densities of faecal indicator bacteria were recovered, and among them enterococci outnumbered the coliforms. The group of staphylococci was in a fairly constant concentration throughout the period of sampling. Some statistically significant correlations were calculated between yeasts and moulds, Escherichia coli and enterococci and between the latter and Clostridium spores. The data obtained could be a reference point for further studies.     

Co-Morbidity,Ageing and Predicted Mortality in Antiretroviral Treated Australian Men: A Quantitative Analysis

Background

Life expectancy has increased in HIV-positive individuals receiving combination antiretroviral therapy (cART); however, they still experience increased mortality due to ageing-associated comorbidities compared with HIV-negative individuals.

Methods

A retrospective study of 314 Queensland HIV-infected males on cART was conducted. The negative impact of ageing was assessed by estimating the probability of 5-year mortality; comparisons were made between an HIV-specific predictive tool (VACS index) and the Australian Bureau of Statistics (ABS) life-tables to examine potential differences attributed to HIV. The negative impact of ageing was also assessed by the prevalence of comorbidities. Associations between comorbidity and estimates of predicted mortality by regression analysis were assessed.

Results

The mean predicted 5-year mortality rate was 6% using the VACS index compared with 2.1% using the ABS life-table (p<0.001). The proportion of patients at predicted high risk of mortality (>9%) using the VACS index or ABS life-table were 17% and 1.8% respectively. Comorbidities were also more prevalent in this cohort compared with rates of comorbidities in age-matched Australian men from the general population. Metabolic disease (38.2%) was the most prevalent comorbidity followed by renal (33.1%) and cardiovascular disease (23.9%). Multivariate analysis demonstrated that patients with a history of cardiovascular disease had a higher predicted risk of mortality (OR=1.69;95%CI:1.17-2.45) whereas ex-smokers had a lower predicted risk of mortality (OR=0.61;95%CI:0.41-0.92).

Conclusions

Using the VACS Index there is an increased predicted risk of mortality in cART-treated HIV infected Australian men compared with age-matched men using the ABS data. This increased predicted mortality risk is associated with cardiovascular disease and the number of comorbidities per subject; which suggests that the VACS Index may discriminate between high and low predicted mortality risks in this population. However, until the VACS Index is validated in Australia this data may suggest the VACS Index overestimates predicted mortality risk in this country.     

Genetic diversity of Escherichia coli isolated from urban rivers and beach water

Repetitive element anchored PCR was used to evaluate the genetic profiles of Escherichia coli isolated from surface water contaminated with urban stormwater, sanitary sewage, and gull feces to determine if strains found in environmental samples reflect the strain composition of E. coli obtained from host sources. Overall, there was less diversity in isolates collected from river and beach sites than with isolates obtained from human and nonhuman sources. Unique strain types comprised 28.8, 29.2, and 15.0% of the isolate data sets recovered from stormwater, river water, and beach water, respectively. In contrast, 50.4% of gull isolates and 41.2% of sewage isolates were unique strain types. River water, which is expected to contain E. coli strains from many diffuse sources of nonpoint source pollution, contained strains most closely associated with other river water isolates that were collected at different sites or on different days. However, river sites impacted by sewage discharge had approximately 20% more strains similar to sewage isolates than did sites impacted by stormwater alone. Beach sites with known gull fecal contamination contained E. coli most similar to other beach isolates rather than gull isolates collected at these same sites, indicating underrepresentation of possible gull strains. These results suggest large numbers of strains are needed to represent contributing host sources within a geographical location. Additionally, environmental survival may influence the composition of strains that can be recovered from contaminated waters. Understanding the ecology of indicator bacteria is important when interpreting fecal pollution assessments and developing source detection methodology.     

Production of Excirolana armata (Dana, 1853) (Isopoda, Cirolanidae) on an exposed sandy beach in southeastern Brazil

The somatic and gonad productions of the cirolanid isopod Excirolana armata were analyzed by taking monthly samples from December 2003 to November 2005 on Una beach, S?o Paulo state (24°S), southeastern Brazil. Sampling was performed along three fixed transects established from the base of the foredunes to the waterline. Weight-specific growth rate was used to estimate the E. armata somatic production for 2004 and 2005, separately. The gonad production was estimated based on the monthly reproductive potential (mean number of eggs/embryos per female × monthly abundance of ovigerous females with near-release broods) for 2004. The annual somatic production of E. armata population varied from 15.57 to 17.25?g AFDW m^?1?year^?1 and the somatic production/biomass ratio (P _s/B) from 3.55 to 3.14?year^?1 for 2004 and 2005, respectively. The P _s/B ratios were higher for males (4.02 and 3.19?year^?1 for 2004 and 2005) than for females (3.10?year^?1 for both years). The annual gonad production (P _g?=?1.07?g AFDW m^?1?year^?1) contributed about 15 and 6% to the total production (P _s?+?P _g) of females and the population, respectively. The proportion of gonad to somatic production of females (P _g/P _s) increased with individual size (ca 90% in the 7.5?mm size class), and the annual weight-specific gonad production (P _g/B ratio) was estimated to 0.24?year^?1. The high P _s/B ratios estimated for E. armata derive from the fast growth of individuals and show the importance of this population to the energy flow on Una beach ecosystem. However, the low percentage of juveniles verified in this population and in other studies of populations of the genus Excirolana is discussed as an important source of underestimation of P _s/B ratio.