Mortality Coefficient Research Articles

Assessment of the fishery, growth and mortality characteristics of the cassava croaker, Pseudotolithus senegalensis (Sciaenidae) from coastal waters of Ghana

This paper reports on the fishery and some population parameters of the cassava croaker (Pseudotolithus senegalensis) at Anlo Beach near Shama (5°01’ N, 1∘37’ W) in the Western Region of Ghana. The study was conducted from July 2012 to June 2013 to contribute to information on the dynamics of demersal stocks in the country. Beach seining was the prime fishing method in the area with the fishing season spanning July to March. Catch per unit effort (CPUE), determined as catch per net haul per day was 9.5 kg in July 2012, 110 kg in January–February 2013 and 47 kg in March 2013. The species was absent from the fishery from April 2013 to June 2013. Monthly catches varied from 2295 kg to 31,500 kg, and specimens of the fish measured 7.5 cm TL to 105.4 cm TL and weighed 2.9 g to 7634 g. The length–weight relationship of the population was described by the equation: BW = 0.005TL3.04 (r=0.99), and grouping the fish at 5 cm class intervals showed modal lengths at 15.0–19.9, 35.0–39.9 and 60.0–64.9 cm TL. Analysis of the length-frequency distribution using the ELEFAN programme indicated an asymptotic length (L∞) of 110.3 cm TL, a growth coefficient (K) of 0.2 yr−1, and total (Z), natural (M) and fishing (F) mortality coefficients of 0.68 yr−1, 0.42 yr−1, and 0.26 yr−1 respectively, for the population. Longevity of the fish was estimated to be 15 years. A low exploitation level of the stock is suggested by the calculated exploitation ratio, E=0.38. These population characteristics are compared with those of other West African P. senegalensis populations.

Sinusoidal growth, recruitment, mortality, yield-per-recruit analysis of Buried fan scallop Mimachlamys funebris (Reeve, 1853) and their implications for mariculture

This study described the growth, mortality, recruitment pattern and exploitation rate of the Buried fan scallop (Mimachlamys funebris) in Asid Gulf, Philippines. Monthly length-frequency data (N=3988) from April 2018 to March 2019 were used to examine population parameters using FISAT II. Two estimates of natural mortalities were used to compare variability of limit exploitation rates. Modelling through the oscillating von Bertalanffy growth function revealed that the species is fast growing (K=1.1 year–1) attaining SH∞ of 10.5 cm. Adequacy in the use of the sinusoidal version of the growth formula hinges on the mean annual temperature difference reported in the gulf to be 2°C. Recruitment pattern was continuous and bimodal throughout the year with two high pulses in April–May and September consistent with the reproductive seasonality reported for congeneric species. Fishing mortality coefficients (4.26 and 4.82 year–1) were higher than the natural mortality coefficients (0.543 and 1.1 year–1). Yield and biomass-per-recruit analysis showed that the current exploitation rates are 112% (Ecurr1 = 0.90) and 92% (Ecurr2 = 0.80) higher than the biological reference points adopted for the study particularly E50. These results demonstrate that M. funebris stock is overexploited, which necessitates effective management measures including mariculture.

Implementation of the pact for health in Brazil: what changes did it bring to child mortality?

This study aimed to verify the association of social inequalities with infant mortality rate so as to infer what has changed in Brazil with the implementation of the Pact for Life. This was an epidemiological ecological study of the time series type with spatial correlation carried out through the Mortality Information System, considering the years from 1996 to 2016. For the development and analysis of the data, the 161 Intermediate Regions of Urban Articulation were considered. The infant mortality coefficient in the years studied was the dependent variable, and as independent variables, the ones selected were the Human Development Index, Gini Index, percentage of poor people and the coverage of the Family Grant Program. Descriptive data were analyzed in the Statistical Package for the Social Sciences. Mortality data were spatialized to determine bivariate spatial autocorrelations using the Geoda software. It was identified in the results that there was a decrease in the infant mortality rate in the decades; spatial autocorrelation showed high coefficients in the Northeast in the first decade, and higher coefficients in the North and Midwest in the second decade. In the bivariate analysis of the infant mortality coefficient with the Human Development Index, greater autocorrelation was observed in the Southeast, South and Midwest regions in the two decades; with the Gini index, the first decade showed autocorrelation in the North and Northeast, and in the second decade, there was autocorrelation in the North, Northeast, and Midwest. When assessed with poverty, autocorrelation was observed in the North and Northeast; and with coverage of the Family Grant Program, autocorrelation was concentrated in the Northeast. Even before and after the release of the Pact for Life, social inequalities were directly related to infant mortality. The Pact, which had one of its indicators the reduction in infant mortality, was effective when evaluated in isolation, however, despite the decrease in this problem.

Population dynamics of Mormyrus rume (Valenciennes, 1847; Osteoglossiformes; Mormyridae) Of Ikere-Gorge, Iseyin, Oyo State, Nigeria

The structure of a fish population is determined by the equilibrium between growth, recruitment and total mortality. But, there is paucity of information on the growth and mortality of Mormyrus rume in Nigeria. Therefore this study is needful to determine its population parameters, with a view of evolving management strategies for its sustainable exploitation. Estimates of population parameters of Mormyrus rume were obtained from length-frequency data of 836 individuals collected monthly for a period of 24 months from January 2017 to December 2018. The estimated growth parameters were: asymptotic length (L∞) was 100.8cm; growth coefficient (K) was 0.62/year; growth performance (Ɵ) was 3.8; length at maturity (Lm) was 52.57cm; reproductive load (Lm/L∞) was 0.52 and optimum length (Lopt) was 65.10cm. Likewise, natural, fishing and total mortalities were 0.93, 1.46 and 2.39 respectively. The values of exploitation rate (0.61) and ratio of total mortality and growth coefficient (3.85) showed that Mormyrus rume is most exploited in Ikere-gorge. Therefore, appropriate fishing regulations should be enforced to regulate fishing gears and mesh size that will fish Mormyrus rume at sustainable level.
 Keywords: Recruitment, mortality, growth, exploitation, length

Population dynamics and stock assessment of deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) from the Mediterranean Coast of Morocco

The population dynamics and stock parameters of the deep water rose shrimp Parapenaeus longirostris (Lucas, 1846) was investigated from the Mediterranean coast of Morocco. Length-frequency data were collected from landings of coastal trawlers at M’diq Port on the Moroccan Mediterranean coast over a period of 13 months from April 2017 to April 2018. The estimated growth parameters were CL∞ = 52.87 mm, K = 0.39 yr-1 and to = - 0.35 .Total mortality coefficient (Z) was estimated as 3.49 yr-1 while the natural mortality estimated using two different methods was 1.89 yr-1 and 1.36 yr-1 and correspondingly the fishing mortality was calculated as 1.51 yr-1 and 2.13 yr-1. Yield per recruit and relative biomass per recruit analysis showed that the value of current exploitation rate (E) is 0.68 which is higher than the exploitation rate E 0.5=0.36, which indicates that the stock is currently overexploited. Hence it is advised to decrease the present exploitation rate by 50% of the current level to sustain the fishery.

Spatiotemporal clustering, social vulnerability and risk of congenital syphilis in northeast Brazil: an ecological study.

To investigate the spatial distribution of congenital syphilis (CS) and its association to social vulnerability indexes in northeast Brazil. This was an ecological study referring to all cases of CS and CS deaths recorded in the northeast region of Brazil from 2008 to 2015. Data were obtained from three Brazilian information systems. We examined statistical correlations between CS indicators by state and municipality and their socioeconomic and social vulnerability characteristics. We used Bayesian empirical local models to identify fluctuations of the indicators. Spatial statistical tests were used to identify spatial clusters and the municipalities at high risk of CS. The incidence of CS ranged from 2.1 cases/1000 live births (LB) in 2008 to 6.9/1000 LB in 2015, with an annual increase of 19.9% (p<0.001). The mortality coefficient of CS ranged from 2.9/1000 LB in 2008 to 6.5/1000 LB in 2015, resulting in an annual increase of 15.1% (p<0.001). Nine spatial clusters were identified. Cases of congenital syphilis occurred in well-defined spatiotemporal clusters and in areas with high levels of social vulnerability. CS incidence is associated with social vulnerability. CS control programmes should target spatial clusters and populations with high levels of social vulnerability.

Demographic structure and stock status of Lethrinus lentjan in Saudi coastal waters of the Red Sea.

Fishes of the family Lethrinidae form a considerable portion of the catch from both the Red Sea and the Arabian Gulf in Saudi Arabia, and the species Lethrinus lentjan (Lacepède, 1802) is one of the most important among these fishes. This study was conducted to evaluate the demographic structure coefficients, survival rate, and stock status of L. lentjan from the Red Sea coast of Saudi Arabia. A total of 593 samples were collected on a monthly basis for a period of one year from the landing site for fishing boats operating in Red Sea waters off Jeddah. The results indicated that 88.87% of the specimens were female; the maximum total length recorded was 43.5 cm with the most frequent length (14.67%) being 23–23.9 cm. The maximum age recorded for both males and females was 6 year-plus, and the 1 year-plus age category represented the majority of the samples (57.67%). The total mortality coefficient, natural mortality coefficient, and fishing mortality coefficient were 1.538, 0.315, and 1.223, respectively; all mortality coefficients in the female fishes were higher than those in the male fishes. The survival rate of males was higher (0.617) than that of females (0.214). The results of the present study indicate that L. lentjan is subjected to overfishing and a new management strategy is necessary to improve the stock status of this fish species.

Population biology of common carp, Cyprinus carpio (Linnaeus, 1758), in Lake Naivasha, Kenya

AbstractThe common carp (Cyprinus carpio) is an exotic fish, being one of the commercially important species in Lake Naivasha. The present study investigated its growth, mortality, maturity, condition and exploitation. Sampling was done monthly from January to December 2017 with gillnets of 2–5 inches mesh size. Each individual fish was measured (cm) and weighed (g) in the field. The specimens were preserved in ice and transported to the laboratory for analysis of maturity. The fish lengths ranged from 12.0 to 69.0 cm TL, and weighed between 32 and 6,840 g. The overall population sex ratio was 1:1.66 (female:male). The length at first maturity (Lm50) was calculated to be 54.0 and 49.0 cm for females and males, respectively. The length at first capture (23.9 cm) was lower than its length at first maturity, suggesting the capture of immature fish. The mean condition factor for all fish was 1.05. The peak condition values were observed during April (1.35), September (1.59) and October (1.80). The highest (1.377) mean condition was observed for size class 56–60 and the lowest (0.933) in class 26–30. The asymptotic length (L∞) was 73.5 cm, and the growth curvature (K) was 1.05 year‐1, with a growth performance index (Ф) of 3.72. The total (Z), natural (M) and fishing (F) mortality coefficients were 2.85, 1.34 and 1.78 year‐1, respectively. The exploitation rate (E) of 0.57 year‐1 was higher than the optimum sustainable yield (E0.5) of 0.32, but was not different from the maximum sustainable yields (Emax) 0.54 and economic yield (E0.1) 0.46. The results of the present study provide parameters of fish biology and population that should prove useful in managing the fishery of Lake Naivasha.

The forecasting of COVID-19 with mortality using SIRD epidemic model for the United States, Russia, China, and the Syrian Arab Republic

In this paper, we apply an algorithm for simulating the susceptible-infected-recovered-dead pandemic model for demonstrating the forecasting and the spreading of the new coronavirus disease. For this purpose, we apply an implicit analytical solution for parts of the model, in addition to applying the finite difference methods for other parts of the model. Based on the collected data of the number of infected cases, recovered cases, and deceased cases of the new coronavirus pandemic as of 30 May 2020, we find the values of the coefficient of infection, the coefficient of recovery, and the coefficient of mortality of the new coronavirus pandemic for four different countries, namely, China, the United States, Russia, and the Syrian Arab Republic. Besides, we find the ratio of the average rate of recovery to the average rate of death of the new coronavirus pandemic for the same four countries. For the following months, we predict the number of the infected cases, the recovered cases, and the deceased cases of the pandemic for the United States, Russia, and the Syrian Arab Republic using the methods normally used for the epidemic model. We find that the number of infected cases of the new coronavirus disease may increase to about two million cases in the United States, about eight hundred thousand cases in Russia, and about three hundred cases in the Syrian Arab Republic. We believe that the algorithm we use for simulating the spreading and the forecasting of the new coronavirus disease can be applied for finding other related coefficients of the pandemic such as the basic reproduction numbers with a certain population.

Epidemiological profile of alcoholic liver disease hospital admissions in a Latin American country over a 10-year period.

Alcoholic liver disease (ALD) is a major cause of chronic liver disease worldwide. To describe the epidemiological profile and mortality rates of patients with ALD admitted to public hospitals in different regions of Brazil from 2006 to 2015. This is a descriptive study that evaluated aggregate data from the five Brazilian geographic regions. A total of 160093 public hospitalizations for ALD were registered. There was a 34.07% increase in the total number of admissions over 10 years, from 12879 in 2006 to 17267 in 2015. The region with the highest proportion (49.01%) of ALD hospitalizations was Southeast (n = 78463). The North region had the lowest absolute number of patients throughout the study period, corresponding to 3.9% of the total (n = 6242). There was a 24.72% increase in the total number of ALD deaths between 2006 and 2015. We found that the age group between 50 and 59 years had the highest proportion of both hospitalizations and deaths: 28.94% (n = 46329) of total hospital admissions and 29.43% (n = 28864) of all deaths. Men were more frequently hospitalized than women and had the highest proportions of deaths in all regions. Mortality coefficient rates increased over the years, and simple linear regression analysis indicated a statistically significant upward trend in this mortality (R² = 0.744). Our study provides a landscape of the epidemiological profile of public hospital admissions due to ALD in Brazil. We detected an increase in the total number of admissions and deaths due to ALD over 10 years.

The impact of the nurses\u2019, doctors\u2019 and clinical officer strikes on mortality in four health facilities in Kenya

BackgroundHealth worker strikes are a significant threat to universal access to care globally and especially in sub Saharan Africa. Kenya’s health sector has seen an increase in such industrial action. Globally there is limited data that has examined mortality related to such strikes in countries where emergency services were preserved. We sought to assess the mortality impact of an 100 day physician strike which was followed by 151 day nurses’ strike and 20 day clinical officer strike in Kenya.MethodsMonthly mortality data was abstracted from four public hospitals, Kenyatta National Referral Hospital, AIC Kijabe Hospital, Mbagathi Hospital and Siaya Hospital between December 2016 and March 2018. Differences in mortality were assessed using t-tests and multiple linear regression adjusting for facility, numbers of patients utilizing the hospital and department.ResultsThere was a significant decline in the numbers of patients seen, comparing the non-strike and strike periods; beta (ß) coefficient − 649 (95% CI -950, − 347) p < 0.0001. The physicians’ strike saw a significant decline in mortality (ß) coefficient − 19.0 (95%CI -29.2, − 8.87) p < 0.0001. Nurses and Clinical Officer strikes’ did not significantly impact mortality. There was no mortality increase in the post-strike period beta (ß) coefficient 7.42 (95%CI -16.7, 1.85) p = 0.12.ConclusionDeclines in facility-based mortality during strike months was noted when compared to a non-striking facility, where mortality increased. The decline is possibly associated with the reduced patient volumes, and a possible change in quality of care. Public health facilities are congested and over-utilized by the local population majority of whom cannot afford even low cost private care. Health worker strikes in Kenya where the public health system is the only financially accessible option for 80% of the population pose a significant threat to universal access to care. Judicious investment in the health infrastructure and staffing may decrease congestion and improve quality of care with attendant mortality decline.

Population Biology of Nile tilapia (Oreochromis niloticus) in Lake Naivasha, Kenya

AbstractThe Nile tilapia (Oreochromis niloticus) was introduced into Lake Naivasha to provide exploitable fisheries, being one of the commercially important fish providing livelihoods to communities around the lake. Its stocks in the lake have been declining, however, because of intense fishing, ecological changes and effects of other exotic species. The present study was undertaken to investigate the population and biological parameters of Oreochromis niloticus. Fish samples (1,021) were caught monthly from January to December 2017, collecting a total of 1,021 O. niloticus, with an overall sex ratio of 2.21:1.0 (male: female). The length of the fish ranged from 9.0 to 40.0 cmTL and weighed between 20 and 1,220 g. The mean length and weight for all fish was 22.6 cm and 272.6 g. The slope b of length–weight relationship was 2.86 for all fish, indicating negative allometry. The mean condition factors were 0.99, 1.04 and 1.01 for male, female and all fish, respectively. The length at first maturity (Lm50) was estimated to be 28.0 cmTL for all sexes, indicating the fish matures at smaller sizes. The length at first capture (Lc50) was calculated to be 19.38 cm, a value much lower than its Lm50, reflecting the capture of juvenile fish. The asymptotic length (L∞) was 42 cm, the growth coefficient (K) was 0.21/year, and the growth performance index (Ф) was 2.57. The natural (M), fishing (F) and total mortality (Z) coefficients were estimated to be 0.55, 0.26 and 0.80/year, respectively. The optimum sustainable yield (E0.5), maximum sustainable yield (Emax) and maximum economic yield (E0.1) indices of 0.23, 0.35 and 0.26, respectively, imply an optimal exploitation of O. niloticus. The results of the present study provided some important insights into the biology and management needs of the O. niloticus fishery in Lake Naivasha, as well as revealing a gap for further research on its reproductive biology.

WEATHER CONDITIONS, AIR POLLUTION, EMERGENCY CALLS AND POPULATION MORTALITY IN PETROZAVODSK

The aim of the present study is to assess the associations between weather factors, atmospheric air pollution and the number of emergency medical calls (EMC) and population mortality Petrozavodsk, Northwest Russia. Methods. Linear correlations between the monthly values of external factors, the number of EMC for people with cardiovascular diseases and the total mortality werestudied. Graphs of the long-term associations betweenmortality rates and pollutant emissions from stationary sources were constructed. Results. Longterm average annual temperature of atmospheric air increased from +3.1 °C (1994-2001) to +3.8 °C (2002-2017) and the frequency of northwestern wind (FNWWD) increased by an average of 29.5 % during the same periods. This wind direction is associated with health-related problems in the city related to the spread of emissions from stationary contamination sources. A strong statistical relationship between the annual amount of emissions and mortality coefficients (total and from diseases of the circulatory system) for the period 2002-2017 was observed. A temperature (seasonal) factor is statistically significantly (from p &lt; 0.001 to p = 0.034) associated with frequency of EMC for essential hypertension, angina pectoris (2015-2017) and chronic coronary heart disease (2016, 2017). A positive correlation between FNWWD and the number of EMC for people with acute myocardial infarction (p = 0.015) and stroke (p = 0.011) for a three-year period (2015-2017) was revealed. Conclusions. The results of the study indicate the need to take into account the influence of weather conditions and air pollution on the frequency of emergency medical calls and the patterns of mortality in urban settings.

Severe coral loss shifts energetic dynamics on a coral reef

Abstract Declining coral cover and loss of structural complexity are widely reported on today's coral reefs. While coral loss frequently triggers changes in coral reef fish assemblage structure, the ecosystem‐scale consequences of these changes are poorly known. Here we evaluate how four metrics of energy flow and storage that underscore a critical coral reef function, consumer biomass production, respond to severe coral loss on a coral reef in the northern Great Barrier Reef, Australia. We compared fish and benthic surveys at Lizard Island from 2003 to 2004 with surveys in 2018 using an individual‐level modelling approach that integrates growth and mortality coefficients to estimate community‐level standing biomass, productivity, consumed biomass and turnover. In the study period, coral cover declined by 72%–83% in forereef zones while turf cover increased by 18%–100% across all zones. Reef fish assemblages, in turn, responded with a 71% increase in standing biomass, 41% in productivity and 37% in consumed biomass, mainly driven by nominally‐herbivorous fishes (Labridae—Scarini, Acanthuridae and Siganidae). By contrast, biomass turnover rates declined by 19%. Our findings suggest that coral loss can drive energetic shifts on coral reefs, leading to more productive, but slower paced reef fish assemblages. Although the observed build‐up of biomass may appear positive, the decreased turnover rates indicate that the system is unable to maintain biomass replacement levels. This suggests that the enhanced productivity that accompanied coral loss may be driven by storage effects from the somatic growth of individuals already present, questioning the temporal stability of these changes to coral reef ecosystem functioning. A free Plain Language Summary can be found within the Supporting Information of this article.

The comparative analysis of coefficients of variation of standard regional indices of mortality and causes having and having not accurate criteria of diagnostics

The standardized mortality coefficients for different causes have significant variability between regions and depend on many factors. The purpose of study was to investigate interregional variation coefficients of standardized mortality of oncologic diseases as compared with other causes having no explicit diagnosis criteria. The 49 death causes were selected out of 295 causes of the Short nomenclature of the Rosstat. These causes were distributed by 2 groups: neoplasms and causes without explicit diagnostic criteria. The standard mortality indicator was calculated on the basis of the European standard. The significance of differentiations between the groups was estimated using one-factor dispersion analysis by pair comparison and Bonferroni amendment. The level of interregional variation coefficient of the standard mortality indicator from cancer was lower than from other causes with no explicit diagnostic criteria. Even the reasons of death from oncologic diseases which has no explicit criteria have the significantly less marked variation coefficient as compared to other two groups. There were reliable differences of the variation coefficients between the subgroup of oncologic diseases with precise location of tumor and the subgroup of oncologic diseases of other and non-explicit locations. The death causes due to "other diseases" and the death causes due to diseases with no-explicit diagnostic criteria had similarly high level of variation coefficient. The difference of the regional standard mortality indicator of concrete reasons is affected by uncoordinated criteria of diseases diagnostic and the main reason of death determination. The letter of the Minzdrav of Russia concerning the rules of application of notion "senility" as cause of death played certain role also. The different level of morbidity in regions had the influence as well. The harmonization of verification of all the cases of diagnosis, its "depth" and applied criteria is needed for proper analysis of data of death from separate causes is needed.

Reproduction, Growth, Mortality and Yield of the Goatfish Upeneus sulphureus in Northern Bay of Bengal, Bangladesh

Information on stock condition and reproductive biology are important for fisheries conservation and management planning. This study examined reproduction, growth, mortality and yield of sulphur goatfish (Upeneus sulphureus Cuvier 1829), which is a low-value food fish abundantly caught as bycatch in artisanal and industrial fishing from the southeast coast of Bangladesh at northern Bay of Bengal. Data were collected monthly obtaining samples from local fish landing center. The gonadosomatic index indicated that U. sulphureus spawns twice a year during January–May and August–October. Fecundity of the fish was positively correlated with the body and gonad weight, and varied from 15 128–97 274 eggs with fish weight 11.30–58.73 g. Monthly length–frequency distribution was analyzed through FISAT software, thus the estimated seasonalized von Bertalanffy growth parameters were L∞ = 21.80 cm, K = 0.54 per year, C = 0.5, WP = 0.1 and Rn = 0.300, respectively. Moreover, the value of seasonalized total mortality coefficient Z (2.24) was smaller than that of the non-seasonalized Z (4.16). The instantaneous natural mortality and fishing mortality, calculated for non-seasonalized total mortality, were 1.31 and 2.86, respectively. Furthermore, the high exploitation rate (E = 0.69) was close to maximum exploitation level (Emax = 0.75) in yield-per-recruit analysis, suggesting that U. sulphureus is being exploited at the MSY (maximum sustainable yield) level. Therefore, further increase in fishing effort may reduce U. sulphureus stocks in the coastal waters of Bangladesh.

Temporal trend of HIV/AIDS cases in the state of Minas Gerais, Brazil, 2007-2016.

to analyze the temporal trend of Human Immunodeficiency Virus (HIV) and Acquired Immune Deficiency Syndrome (AIDS) incidence, detection and mortality coefficients in the state of Minas Gerais between 2007 and 2016. this was a time series study of data held on the Notifiable Health Conditions Information System (Sinan) using Prais-Winsten regression. in the period studied, 35,349 cases were notified, with predominance of sexually transmitted cases (81.7%), 50.3% of which were heterosexual cases and 22.8% were homosexual cases. AIDS incidence increased (annual change 1.6%; 95%CI 0.0;3.3) as did HIV detection (annual change 60.3%; 95%CI 22.9;109.0). The mortality rate was stationary; HIV+ notifications increased from 3.8% in 2007 to 65.1% in 2016. the growing trend of HIV+ detection coincided with the government strategy to identify cases. AIDS incidence increased.

ANÁLISE ESPACIAL E TENDÊNCIA DA MORTALIDADE POR CÂNCER DE PÊNIS EM SERGIPE, 2000 A 2015

Objetivo: analisar a distribuição espacial e a tendência temporal da mortalidade por câncer depênis em Sergipe.Método: estudo ecológico, com técnicas de análise espacial. Foram utilizados dados secundáriosdos óbitos por câncer de pênis de residentes dos municípios de Sergipe de 2000 a 2015, obtidosno Sistema de Informações sobre Mortalidade. A análise das tendências temporais foi realizadapelo programa Joinpoint por meio da regressão Poisson. As análises espaciais foram realizadas pormeio do modelo bayesiano empírico, estimador de Kernel e Índices de Moran.Resultados: ocorreram 67 óbitos por câncer de pênis e uma tendência crescente dos coeficientesde mortalidade, de 0,11 (2000) para 0,64 (2015) por 100.000 homens. Observou-se autocorrelaçãoespacial positiva (I=0,64; p=0,01) com áreas de maior risco de morte localizadas na região sul doestado.Conclusão: houve aumento dos coeficientes de mortalidade por câncer de pênis e distribuiçãogeográfica heterogênea das áreas de risco.

Current status of Liza ramada (Risso, 1810) (Mugilidae) caught by trammel net (Ballah) at El-Gamil region, Manzala Lake, Egypt

Liza ramada, the target species caught by trammel net (Ballah) at El-Gamil region, north of Lake Manzala, is studied to estimate the life history parameters by using length–frequency data of 842 specimens. The life span was estimated as 4 years. It exhibited a negative allometric growth (b=2.94). The von Bertalanffy growth parameters were L∞= 30.45cm, K= 0.48 yr−1 and t0 =-0.339 yr−1 with a derived growth performance index of O′ =2.6 .The mean annual instantaneous total, natural and fishing mortality coefficients were 1.47, 0.71and 0.76/year, respectively. The exploitation rate was estimated as 0.52. The probability of capture ensured that 50 percent (Lc) of the fish caught was estimated at length 12.18 cm which is 31.2% lower than the length at first sexual maturity (17.7 cm) and lower by 40.1% than the estimated Lopt value (20.4 cm). This result reflects the smaller mesh sizes of the inner layer of nets used by fishermen. Therefore an urgent recommendation should be applied to prevent the illegal fishing gears, increase the mesh sizes especially for the inner layer of trammel net used as well as improving the quality of water discharged into the lake to increase the yield per recruit of Liza ramada, protect fish stocks and to secure a profitable fisheries and optimum catch efficiency for the future.

Characteristic changes in the population dynamics of asari (Manila) clam Ruditapes philippinarum in a period of stock decrease on the Banzu intertidal flat, Tokyo Bay

In Tokyo Bay, harvesting of asari (Manila) clam Ruditapes philippinarum has decreased since the early 2000s. In the present study, based on the abundance of sampled clams in four sites from 1998 to 2015 in the Banzu intertidal area, the authors discussed changes in the processes of population dynamics of asari clam which are possibly related to harvest decrease in Tokyo Bay. The findings are summarized as following two points. Firstly, the recent decline in the harvest of asari clams in Tokyo Bay may be caused by the mortality of benthic juveniles. The spatial density of juvenile clams at recruitment showed a varied increase during the study period. In contrast, from the recruitment to adult stages, the mortality coefficient z and von Bertalanffy growth function k consistently increased and decreased, respectively. Moreover, decreasing trends in the spatial density of adult clams were apparent in the concurrent period. Thus, the decrease of adult clams was suggested to be due to poor survival in juvenile clams after recruitment. Secondly, the depletion of the autumn cohort and spatial relocation of the large juveniles were apparent after 2009. The autumn cohort significantly decreased in size-frequency composition, despite the increased abundance and size of juvenile clams at recruitment after 2009. Referring to recent reports, predation by fish may be one of the processes that depleted the abundance of the autumn cohort. Additionally, the density of year-class cohorts increased for 2–4 months from their first appearance to the completion of recruitment, which was likely due to the spatial immigration of large juveniles into the study area. The physical stress of sea water movement caused by increasing strong wind may have encouraged the spatial transport of the juveniles. The depletion of the autumn cohort and spatial immigration of the large juveniles were temporally overwrapped with the period of an outbreak and continuing infestation of the parasitic sea spider Nymphonella tapetis after 2007. This observation can hypothesize that poor burrowing activity due to the parasitic infestation allowed the clams to suffer predation or passive transport. However, above changes in population dynamics after the late 2000s cannot be solely connected to decline of asari harvest, because that decrease in the harvest of asari clams in Tokyo Bay began in the early 2000s; there remain factors other than this one that may have acted on the stock decline after the early 2000s in Tokyo Bay.