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Total Mortality Rate (total + mortality_rate)
Selected AbstractsGrowth and mortality of the catfish, Hemisynodontis membranaceus (Geoffroy St. Hilaire), in the northern arm of Lake Volta, GhanaFISHERIES MANAGEMENT & ECOLOGY, Issue 1 2001P. K. Ofori-Danson Estimates of growth and mortality of the catfish, Hemisynodontis membranaceus (Geoffroy St. Hilaire), in Lake Volta were obtained from length composition data compiled in 1995 and 1996. The von Bertalanffy growth function (VBGF) estimates were: L,=44.5 cm standard length; K=0.62 year,1; and t0=,0.23 years. Natural mortality rate, M, was 1.20 year,1. Total mortality rate, Z, was computed as 4.39 year,1 and the exploitation ratio (E=F/Z) was 0.72. Although the fish is estimated to have longevity of about 5 years, those exploited are normally less than 2 years of age, which is indicative of growth over-fishing. In order to arrest over-exploitation of the species, there is a need to establish ,lake reserves'. In addition, the fisheries management should be devolved from the state to the local level to compel fishermen to take greater responsibility for the sustainability and conservation of the fisheries. [source] Growth and mortality of the brushtooth lizardfish (Saurida undosquamis) in Iskenderun Bay (eastern Mediterranean Sea) using length frequency analysisJOURNAL OF APPLIED ICHTHYOLOGY, Issue 6 2007G. Gökçe Summary The growth and mortality of brushtooth lizardfish Saurida undosquamis (Richardson, 1848) in Iskenderun Bay (eastern Mediterranean Sea) were investigated based on length frequency data using the fisat software. Total length of the sampled 4711 fish ranged from 6.0 to 39.0 cm. The von Bertalanffy growth function estimates were L, = 42.00 cm, k = 0.51 year -1, t0 = ,0.29 years. Total mortality rate (Z) was computed as 1.76 year -1 and the exploitation ratio was 0.51, indicating that the brushtooth lizardfish stock is on the verge being overfished. [source] Yield, growth and mortality rate of the Thai river sprat, Clupeichthys aesarnensis, in Sirinthorn Reservoir, ThailandFISHERIES MANAGEMENT & ECOLOGY, Issue 4 2003T. Jutagate Abstract The Thai river sprat, Clupeichthys aesarnensis Wongratana, is a clupeid with a short life span, and supports artisanal fisheries in a number of reservoirs in the Mekong Basin. The growth parameters, mortality rates and the status of the Thai river sprat in Sirinthorn Reservoir (28 800 ha), NE Thailand (15°N; 105°E), are presented. The fishery is based on lured lift-nets, operated 7,14 days in the new moon period, September to April each year. It was shown that the von Bertalanffy growth function (VBGF) model was Lt (mm) = 78.43[1 , exp{,0.211[t , (,0.7996)]}] and its growth conformed to an isometric pattern. Natural mortality rate (month,1) was 0.13 month,1. Total mortality rates ranged from 0.69 to 1.53 month,1 depending on the weather and the fishing season. Recruitment was continuous throughout the year but peaked in June and July. The yield per recruit model indicated that the exploitation rate of this fishery is probably too high. [source] Long-Term Survival in Patients Treated with Cardiac Resynchronization Therapy: A 3-Year Follow-Up Study from the InSync/InSync ICD Italian RegistryPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2006MAURIZIO GASPARINI Background: Studies reporting the long-term survival of patients treated with cardiac resynchronization therapy (CRT) outside the realm of randomized controlled trials are still lacking. The aim of this study was to quantify the survival of patients treated with CRT in clinical practice and to investigate the long-term effects of CRT on clinical status and echocardiographic parameters. Methods: The study population consisted of 317 consecutive patients with implanted CRT devices from eight Italian University/Teaching Hospitals. The patients were enrolled in a national observational registry and had a minimum follow-up of 2 years. A visit was performed in surviving patients and mortality data were obtained by hospital file review or direct telephone contact. Results: During the study period, 83 (26%) patients died. The rate of all-cause mortality was significantly higher in ischemic than nonischemic patients (14% vs 8%, P = 0.002). Multivariate analysis showed that ischemic etiology (HR 1.72, CI 1.06,2.79; P = 0.028) and New York Heart Association (NYHA) class IV (HR 2.87, CI 1.24,6.64; P = 0.014) were the strongest predictors of all-cause mortality. The effects of CRT persisted at long-term follow-up (for at least 2 years) in terms of NYHA class improvement, increase of left ventricular ejection fraction, decrease of QRS duration (all P = 0.0001), and reduction of left ventricular end-diastolic and end-systolic diameters (P = 0.024 and P = 0.011, respectively). Conclusions: During long-term (3 years) follow-up after CRT, total mortality rate was 10%/year. The outcome of ischemic patients was worse mainly due to a higher rate of death from progressive heart failure. Ischemic etiology along with NYHA class IV was identified as predictors of death. Benefits of CRT in terms of clinical function and echocardiographic parameters persisted at the time of long-term follow-up. [source] | ||||||||||