Size-Biased Survival in Steelhead Trout (Oncorhynchus mykiss): Back-Calculated Lengths from Adults' Scales Compared to Migrating Smolts at the Keogh River, British Columbia

1989 ◽  
Vol 46 (11) ◽  
pp. 1853-1858 ◽  
Author(s):  
B. R. Ward ◽  
P. A. Slaney ◽  
A. R. Facchin ◽  
R. W. Land
Keyword(s):  
Salt Water ◽  
Survival Rates ◽  
Length Distribution ◽  
Adult Survival ◽  
Steelhead Trout ◽  
Island Size ◽  
Back Calculation ◽  
Males And Females ◽  
The Mean ◽  
Calculation Procedures

Lengths of wild, winter-run steelhead smolts, estimated by back-calculation procedures from adults' scales, were compared with observed lengths of migrating smolts sampled near the mouth of the Keogh River, Vancouver Island. Size-biased smolt-to-adult survival rates were estimated for several length categories by utilizing length frequencies from observed smolts, smolt length frequencies which were back calculated from adults' scales, smolt yield, and adult returns. Back-calculated smolt length (BSL) of adults returning from smolts of 1977 to 1982 averaged 193 mm compared to 176 mm for observed smolt length (OSL). Mean BSL was larger than OSL in every year. Adults from odd-numbered smolt years had larger BSL than adults from even-numbered smolt years similar to the pattern in OSL. BSL increased with increased years spent in salt water, based on ageing adults' scales. Males and females had different BSL based on number of years spent in fresh water and salt water, although they exhibited the same mean BSL overall. The smolt-to-adult survival estimates were in close agreement with previous estimates derived from the mean OSL. Predictability of survival in the ocean based on the length of smolts was extended over a broad range of the length distribution of wild steelhead smolts.

Effect of Smolt Size on Smolt-to-Adult Survival for Chilko Lake Sockeye Salmon (Oncorhynchus nerka)

1991 ◽  
Vol 48 (6) ◽  
pp. 988-994 ◽  
Author(s):  
M. A. Henderson ◽  
A. J. Cass
Keyword(s):  
Sockeye Salmon ◽  
Interannual Variation ◽  
Oncorhynchus Nerka ◽  
Fork Length ◽  
Adult Survival ◽  
Threefold Increase ◽  
Limited Variation ◽  
Back Calculation ◽  
The Mean ◽  
Calculation Procedures

Three approaches were used to test the hypothesis that smolt-to-adult survival is independent of smolt size for Chilko Lake sockeye salmon (Oncorhynchus nerka). The mean distance between the focus of the scale and the first annulus, a reliable indicator of smolt size, was greater for adult scales than for smolt scales from the same brood year in two of the three years we examined. This indicated a higher smolt-to-adult survival for larger smolts in these brood years. The abundance of smolts of different fork lengths, based on back-calculation procedures from adult scales, was compared with the abundance of smolts of different fork lengths at the time of outmigration within brood years. In all three years studied, there was a two- to threefold increase in smolt-to-adult survival as smolt length increased. However, there was no significant relationship between smolt-to-adult survival and mean annual smolt fork length based on a 34-yr time series; this lack of relationship was probably caused by limited variation in mean annual smolt fork length over the 34-yr period and other variables, independent of smolt size, that affect survival and exhibit considerable interannual variation.

Age distribution of breeding female Antarctic fur seals in relation to changes in population growth rate

1990 ◽  
Vol 68 (10) ◽  
pp. 2209-2213 ◽  
Author(s):  
I. L. Boyd ◽  
N. J. Lunn ◽  
P. Rothery ◽  
J. P. Croxall
Keyword(s):  
Population Growth ◽  
Survival Rates ◽  
Age Distribution ◽  
Adult Survival ◽  
South Georgia ◽  
Breeding Female ◽  
Fur Seals ◽  
Rate Of Increase ◽  
The Mean ◽  
Antarctic Fur Seals

The age distribution of breeding female Antarctic fur seals at Bird Island, South Georgia, in 1988 was compared with the age distribution of a sample obtained in 1971–1973. The mean age in 1971–1973 was 7.41 (SE = 0.26) years and in 1988 it was 6.93 (SE = 0.20) years. After correction for age-dependent arrival time at the pupping beach in 1988, the mean age was 6.22 (SE = 0.14 years), which was significantly lower than in 1971–1973. Indicators of population size suggested that population growth at Bird Island had declined to below 3% annually by 1988 compared with rapid growth (17%) in 1958–1972. Exponential models fitted to the frequency distribution of age-classes greater than age 5 years and corrected for the rate of increase of the population gave adult survival rates of 0.66 (SE = 0.03) and 0.88 (SE = 0.02) for the 1988 and 1971–1973 samples, respectively. The reduced apparent adult survival rate in the 1988 sample was probably caused by emigration brought about by high densities of females on the pupping beaches. There are few signs from this analysis that the fur seal population at South Georgia is close to carrying capacity.

scholarly journals Survival Rates and Capture Heterogeneity of Bottlenose Dolphins (Tursiops truncatus) in the Shannon Estuary, Ireland

2021 ◽  
Vol 8 ◽  
Author(s):  
Kim E. Ludwig ◽  
Mags Daly ◽  
Stephanie Levesque ◽  
Simon D. Berrow
Keyword(s):  
Range Expansion ◽  
Bottlenose Dolphin ◽  
Site Fidelity ◽  
Bottlenose Dolphins ◽  
Survival Rates ◽  
Adult Survival ◽  
Demographic Parameter ◽  
Resident Population ◽  
The Mean ◽  
Survey Effort

Adult survival is arguably the most important demographic parameter for long-lived species as it has a large impact on population growth, and it can be estimated for cetacean populations using natural markings and mark-recapture (MR) modelling. Here we describe a 26-year study of a genetically discrete, resident population of bottlenose dolphins in the Shannon Estuary, Ireland, conducted by an NGO using multiple platforms. We estimated survival rates (SRs) using Cormack-Jolly-Seber models and explored the effects of variable survey effort, multiple researchers, and changes in camera equipment as well as capture heterogeneity induced by changes in marks and site fidelity variation, all common issues affecting longitudinal dolphin studies. The mean adult SR was 0.94 (±0.001 SD) and thus comparable to the estimates reported for other bottlenose dolphin populations. Capture heterogeneity through variation in mark severity was confirmed, with higher capture probabilities for well-marked individuals than for poorly marked individuals and a “transience” effect being detected for less well-marked individuals with 43% only recorded once. Likewise, both SR and capture probabilities were comparatively low for individuals with low site fidelity to the Shannon Estuary, and SR of these individuals additionally decreased even further toward the end of the study, reflecting a terminal bias. This bias was attributed to non-random temporal migration, and, together with high encounter rates in Brandon Bay, supported the hypothesis of range expansion. Our results highlight the importance of consistent and geographically homogenous survey effort and support the differentiation of individuals according to their distinctiveness to avoid biased survival estimates.

scholarly journals Ageing and Growth Records of Anabas testudineus (Bloch) (Anabantidae : Perciformes)

1970 ◽  
Vol 45 (3) ◽  
pp. 283-287
Author(s):  
A Nargis
Keyword(s):  
Growth Rate ◽  
Length Distribution ◽  
Age Group ◽  
Anabas Testudineus ◽  
Total Length ◽  
Back Calculation ◽  
Males And Females

Observations on otoliths of 115 males and 67 females of 1-11 age group have shown that the transparent (hyaline) and opaque rings are formed annually on the Anabas testudineus otolith. The validity of the otolith study has been confirmed by obtaining high co- efficient of correlation (0.94 and 0.93) between total length (TL) and otolith (OR) of 337 males and 387 females of A. testudineus. But the significant differences (t=15.80, D. F=722; P < 0.001) between the sexes have indicated the use of length intercept separately for back calculation for males and females. Growth rate for females (k=0.174, L=237.12) was found to grow faster than that of males (k=0.182, L=18). From the age length distribution it is inferred that on an average, lengths of 105.30±3.98, 122.56±5.22, 143.24 ±5.66 for males and 106.70±5.17, 127.81±5.20 and 145.59±5.42 for females are attained by the species in the respective ages of 3 years of their life spans . Keywords: Growth rate; Stractures of fish; Rapid metabolism DOI: 10.3329/bjsir.v45i3.6539Bangladesh J. Sci. Ind. Res. 45(3), 283-287, 2010

scholarly journals Development, biology, and life table parameters of the predatory species, Clitostethus brachylobus Peng, Ren & Pang 1998 (Coleoptera: Coccinellidae), when fed on the whitefly, Bemisia tabaci (Genn.)

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Xingmin Wang ◽  
Hui Deng ◽  
Cailian Du ◽  
Shaukat Ali
Keyword(s):  
Bemisia Tabaci ◽  
Survival Rates ◽  
Adult Emergence ◽  
Reproductive Rate ◽  
Adult Survival ◽  
Life Stages ◽  
Life Table Parameters ◽  
Net Reproductive Rate ◽  
Female Longevity ◽  
The Mean

Abstract The predatory species, Clitostethus brachylobus Peng, Ren & Pang 1998 (Coleoptera: Coccinellidae), native to China, has been reported as a predator of the whitefly species, Bemisia tabaci (Genn.). Present study describes the development and biological characteristics of C. brachylobus. Developmental periods of different immature stages showed significant differences, when fed on different life stages of B. tabaci. Prey consumption capacity was reduced by the increase in prey age. Female longevity was 193.5 days, whereas fecundity was 154.70 eggs/female. Net reproductive rate was 53.60, whereas the mean generation time was 102.64 days. The daily adult survival rates gradually decreased 120 h post-adult emergence.

Comparative review of Pacific salmon survival rates

1995 ◽  
Vol 52 (6) ◽  
pp. 1327-1338 ◽  
Author(s):  
Michael J. Bradford
Keyword(s):  
Life History ◽  
Survival Data ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Survival Rates ◽  
Adult Survival ◽  
Life History Stages ◽  
Comparative Review ◽  
History Of ◽  
The Mean

I collated estimates of survival from the literature for naturally reproducing populations of the five major commercially harvested species of Pacific salmon (Oncorhynchus spp.) and compared the mean and variability of survival across species and life-history stages. The conclusion that survival rates can be described with a lognormal distribution was extended to include both the marine and freshwater stages. Average egg–fry survival of pink (O. gorbuscha), chum (O. keta), and sockeye (O. nerka) salmon was similar (average 7%) but was significantly lower than that of coho salmon (O. kisutch, 19%). The egg–smolt survival of chinook (O. tshawytscha) was much higher than coho or sockeye that also rear in freshwater for similar periods (7 compared with 1–2%). No direct estimates exist for the marine survival rate of naturally spawning chinook stocks; however, from fecundity and freshwater survival data a species average of 1–2% was derived. Across all species freshwater contributes slightly more to total variation in egg–adult survival than does the ocean, and the schedule of mortality during the egg–adult interval depends on the natural history of each species.

Persistence of giants: population dynamics of the limpet Scutellastra laticostata on rocky shores in Western Australia

2020 ◽  
Vol 646 ◽  
pp. 79-92
Author(s):  
RE Scheibling ◽  
R Black
Keyword(s):  
Population Dynamics ◽  
Western Australia ◽  
Size Structure ◽  
Survival Rates ◽  
Maximum Size ◽  
High Rate ◽  
Adult Survival ◽  
Rocky Shores ◽  
Adult Size ◽  
Decadal Time Scale

Population dynamics and life history traits of the ‘giant’ limpet Scutellastra laticostata on intertidal limestone platforms at Rottnest Island, Western Australia, were recorded by interannual (January/February) monitoring of limpet density and size structure, and relocation of marked individuals, at 3 locations over periods of 13-16 yr between 1993 and 2020. Limpet densities ranged from 4 to 9 ind. m-2 on wave-swept seaward margins of platforms at 2 locations and on a rocky notch at the landward margin of the platform at a third. Juvenile recruits (25-55 mm shell length) were present each year, usually at low densities (<1 m-2), but localized pulses of recruitment occurred in some years. Annual survival rates of marked limpets varied among sites and cohorts, ranging from 0.42 yr-1 at the notch to 0.79 and 0.87 yr-1 on the platforms. A mass mortality of limpets on the platforms occurred in 2003, likely mediated by thermal stress during daytime low tides, coincident with high air temperatures and calm seas. Juveniles grew rapidly to adult size within 2 yr. Asymptotic size (L∞, von Bertalanffy growth model) ranged from 89 to 97 mm, and maximum size from 100 to 113 mm, on platforms. Growth rate and maximum size were lower on the notch. Our empirical observations and simulation models suggest that these populations are relatively stable on a decadal time scale. The frequency and magnitude of recruitment pulses and high rate of adult survival provide considerable inertia, enabling persistence of these populations in the face of sporadic climatic extremes.

Mantle Of The Expert Strategy Effectiveness In The Development Of Creative Thinking

2019 ◽  
Author(s):  
Ibrahim Arman
Keyword(s):  
Creative Thinking ◽  
Role Playing ◽  
Thinking Skills ◽  
Measurement Unit ◽  
Quasi Experimental ◽  
Males And Females ◽  
The Mean ◽  
Girls School ◽  
And Control ◽  
Experimental Group

<p>This study aimed at investigating the Effectiveness of Mantle of the Expert in creative thinking Skills among the 7<sup>th</sup> Graders. The study conducted on a sample of 7<sup>th</sup> Graders at Kober Secondary Boys School and Upper Kober Elementary Girls School. The study sample consisted of (100) students split into two groups (experimental and control). The researcher adopting the Torrance test for creative thinking the verbal image "A" by examining the tests used in the Ristow study (1988), Edwards and Baldov (1987) study, and designing a teacher book for the (engineering and measurement) unit according to the integration between the strategies of the mantle of the expert and role playing.</p> <p>This study adopted quasi-experimental design. It included two groups (experimental and controlled) in two branches (males and females) for each group. The controlled group was taught by using the traditional method whereas the experimental group by the mantle of the expert. The data analyzed using (ANCOVA) test to measure the differences in the development of creative thinking between the control and experimental groups.</p> <p>The Conclusions showed that there are statistically significant differences in the mean scores of the creative thinking test due to the way, gender and interaction between them.</p> <p>Based on the Conclusions of the study, the researcher recommends the need to use the mantles of the expert in the teaching of mathematics.</p>

Symptomatic osteonecrosis of the hip and knee in patients with systemic lupus erythematosus: Prevalence, pattern, and comparison of natural course

Lupus ◽  
2021 ◽  
pp. 096120332110310
Author(s):  
Mehmet Ersin ◽  
Mehmet Demirel ◽  
Mehmet Ekinci ◽  
Lezgin Mert ◽  
Çiğdem Çetin ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Rheumatic Diseases ◽  
Lupus Erythematosus ◽  
Bone Structure ◽  
Survival Rates ◽  
Knee Joints ◽  
Joint Involvement ◽  
Systemic Lupus ◽  
Kaplan Meier ◽  
The Mean

Objective Osteonecrosis (ON), also known as avascular necrosis, is characterized by the collapse of the architectural bone structure secondary to the death of the bone marrow and trabecular bone. Osteonecrosis may accompany many conditions, especially rheumatic diseases. Among rheumatic diseases, osteonecrosis is most commonly associated with systemic lupus erythematosus (SLE). We assessed prevalence and distribution pattern of symptomatic ON in patients with SLE and compare the natural courses of hip and knee ON. Methods 912 SLE patients admitted between 1981 and 2012 were reviewed. SLE patients with symptomatic ON were retrospectively identified both from the existing SLE/APS database. The prevalence of symptomatic ON was calculated; with ON, the joint involvement pattern was determined by examining the distribution of the joints involved, and then the data about the hip and knee joints were entered in the Kaplan-Meier analysis. Kaplan-Meier methods were used to calculate 5- and 10-year rates of ON-related hip (the hip group) and knee survival (the knee group). Results Symptomatic ON developed in various joints in 97 of 912 patients with SLE, and the overall prevalence of ON was detected as 10.6%. The mean age at the time of SLE and ON diagnoses were 27.9 ± 9.9 (14–53) and 34.2 ± 11.3 (16–62) years, respectively. The mean duration from diagnosis of SLE to the first development of ON was 70.7± 60.2 (range = 0–216) months. The most common site for symptomatic ON was the hips (68%, n=66), followed by the knees (38%, n = 37). According to Kaplan-Meier analysis, hip and knee joint survival rates associated with 5-year ON were 51% and 88%, and 10-year survival rates were 43% and 84%, respectively. Conclusion We observed that the prevalence of symptomatic ON in patients with SLE was 10.6%. With the estimated 10-year survival rates of 40% versus 84% for the hip and knee joints, respectively, hip involvement may demonstrate a more aggressive course to end-stage osteoarthritis than the knee involvement.

scholarly journals Warming Arctic summers unlikely to increase productivity of shorebirds through renesting

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah T. Saalfeld ◽  
Brooke L. Hill ◽  
Christine M. Hunter ◽  
Charles J. Frost ◽  
Richard B. Lanctot
Keyword(s):  
Climate Change ◽  
Survival Rates ◽  
The Arctic ◽  
Adult Survival ◽  
Chick Survival ◽  
Ecological Processes ◽  
Bird Populations ◽  
Phenological Mismatch ◽  
Daily Survival ◽  
Adequate Food

AbstractClimate change in the Arctic is leading to earlier summers, creating a phenological mismatch between the hatching of insectivorous birds and the availability of their invertebrate prey. While phenological mismatch would presumably lower the survival of chicks, climate change is also leading to longer, warmer summers that may increase the annual productivity of birds by allowing adults to lay nests over a longer period of time, replace more nests that fail, and provide physiological relief to chicks (i.e., warmer temperatures that reduce thermoregulatory costs). However, there is little information on how these competing ecological processes will ultimately impact the demography of bird populations. In 2008 and 2009, we investigated the survival of chicks from initial and experimentally-induced replacement nests of arcticola Dunlin (Calidris alpina) breeding near Utqiaġvik, Alaska. We monitored survival of 66 broods from 41 initial and 25 replacement nests. Based on the average hatch date of each group, chick survival (up to age 15 days) from replacement nests (Ŝi = 0.10; 95% CI = 0.02–0.22) was substantially lower than initial nests (Ŝi = 0.67; 95% CI = 0.48–0.81). Daily survival rates were greater for older chicks, chicks from earlier-laid clutches, and during periods of greater invertebrate availability. As temperature was less important to daily survival rates of shorebird chicks than invertebrate availability, our results indicate that any physiological relief experienced by chicks will likely be overshadowed by the need for adequate food. Furthermore, the processes creating a phenological mismatch between hatching of shorebird young and invertebrate emergence ensures that warmer, longer breeding seasons will not translate into abundant food throughout the longer summers. Thus, despite having a greater opportunity to nest later (and potentially replace nests), young from these late-hatching broods will likely not have sufficient food to survive. Collectively, these results indicate that warmer, longer summers in the Arctic are unlikely to increase annual recruitment rates, and thus unable to compensate for low adult survival, which is typically limited by factors away from the Arctic-breeding grounds.

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