Models for tagging data that allow for incomplete mixing of newly tagged animals

1998 ◽  
Vol 55 (6) ◽  
pp. 1477-1483 ◽  
Author(s):  
John M Hoenig ◽  
Nicholas J Barrowman ◽  
Kenneth H Pollock ◽  
Elizabeth N Brooks ◽  
William S Hearn ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Survival Rates ◽  
Mortality Rates ◽  
Mixing Model ◽  
Natural Mortality ◽  
Fishing Season ◽  
Total Survival ◽  
Incomplete Mixing ◽  
Tag Shedding

The Brownie models for tagging data allow one to estimate age- and year-specific total survival rates as well as tag recovery rate parameters. The latter can provide estimates of exploitation rates if the tag reporting, tag shedding, and tag-induced mortality rates can be estimated. A limitation of the models is that they do not allow for newly tagged animals to have different survival rates than previously tagged animals because of lack of complete mixing. We develop a model that allows for the animals to be incompletely mixed, or not fully recruited, into the population during the entire year in which they are tagged. There is a penalty in terms of precision associated with the use of this model. To increase the precision, we also developed a model for which it is assumed that animals become fully mixed (recruited) after a portion of the year has elapsed. Sometimes, animals must be tagged after the fishing season has begun. In this case, newly tagged animals experience fishing and natural mortality for only a fraction of the year. The partial-year non-mixing model can be modified to account for this situation.

scholarly journals Multiyear tagging studies incorporating fishing effort data

1998 ◽  
Vol 55 (6) ◽  
pp. 1466-1476 ◽  
Author(s):  
John M Hoenig ◽  
Nicholas J Barrowman ◽  
William S Hearn ◽  
Kenneth H Pollock
Keyword(s):  
Mortality Rate ◽  
Additional Data ◽  
Survival Rates ◽  
Fishing Effort ◽  
Reporting Rate ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Recovery Rates ◽  
Sampling Survey ◽  
Tag Shedding

The Brownie models for multiyear tagging studies can be used to estimate age- and year-specific annual survival rates and tag recovery rates. The latter are composites of the exploitation rates and rates of tag reporting, tag shedding, and tag-induced mortality. It is possible to estimate the exploitation rates if the other components of the tag recovery rates can be quantified. Instantaneous rates of fishing and natural mortality can be estimated if information is available on the seasonal distribution of fishing effort. The estimated rates are only moderately dependent on the timing of the fishing; consequently, the relative effort data can be crude. Information on the timing of the catch over the course of the year can be used as a substitute for the effort data. Fishing mortality can also be assumed to be proportional to fishing effort over years; consequently, if fishing effort is known then the tag reporting rate, natural mortality rate, and a single catchability coefficient can be estimated (instead of natural mortality and a series of fishing mortalities). Although it is possible in theory to estimate both the tag reporting rate and the natural mortality rate with all of these models, in practice it appears necessary to obtain some additional data relating to tag reporting rate to obtain acceptable results. The additional data can come from a variable reward tagging study, a creel or port sampling survey, or from tagged animals that are secretly added to the fishers' catches.

Estimation of Sea Mortality Rates for the 1960 Brood-Year Pink Salmon of Hook Nose Creek, British Columbia

1964 ◽  
Vol 21 (5) ◽  
pp. 1019-1034 ◽  
Author(s):  
Robert R. Parker
Keyword(s):  
British Columbia ◽  
Mortality Rate ◽  
Marine Environment ◽  
Pink Salmon ◽  
Mortality Rates ◽  
Natural Mortality ◽  
Two Stage ◽  
Fishing Season ◽  
Salmon Fry ◽  
Bella Coola

Seaward migrating pink salmon fry at Hook Nose Creek, British Columbia, were estimated to total 1,153,000 in 1961. Of these, 41.5% or 479,000, were marked by amputation of both ventral fins (BV). Following this marking 36,900 fingerling were captured in the marine environment and marked by removal of the adipose and right ventral fins (ARV). During the 1962 fishing season 1,160,645 adult pinks were examined and 7050 BV and 184 ARV marks recognized. For the Hook Nose Creek stock, survival at sea from natural causes is shown to approximate 22% and the rate of exploitation was 95%. This stock is shown to be more exposed to fishing than the Bella Coola stock, for which a rate of exploitation of 69–80% is estimated. Rate of exploitation for Dean Channel stocks is even lower. These differences are explained as due to times of entry and rates of travel through the fishery. The two-stage marking experiment failed to estimate the natural mortality rate of juvenile pinks during the initial 5 weeks of sea life because of this dissimilarity between rates of exploitation on the stocks in the area.

scholarly journals A novel tag-recovery model with two size classes for estimating fishing and natural mortality, with implications for the southern rock lobster (Jasus edwardsii) in Tasmania, Australia

2003 ◽  
Vol 60 (5) ◽  
pp. 1075-1085 ◽  
Author(s):  
Robert J. Latour ◽  
John M. Hoenig ◽  
Daniel A. Hepworth ◽  
Stewart D. Frusher
Keyword(s):  
A Priori ◽  
Survival Rates ◽  
Mortality Rates ◽  
Reporting Rate ◽  
Natural Mortality ◽  
Rock Lobster ◽  
Jasus Edwardsii ◽  
Size Groups ◽  
Lobster Fishery ◽  
Recovery Models

Abstract Multi-year tag-recovery models can be used to derive estimates of age- and year-specific annual survival rates and year-specific instantaneous fishing and natural mortality rates. The latter, which are often of interest to fisheries managers, usually can only be estimated when the tag-reporting rate (λ) and the short-term tag-induced mortality and tag-shedding rate (φ) are known a priori. We present a new multi-year tagging model that permits estimation of instantaneous mortality rates independently of φλ, provided tagged animals from two adjacent size groups are released simultaneously. If the two size groups comprise animals just above and below the minimum harvestable size limit, then it is possible to estimate year-specific instantaneous fishing and natural mortality rates after 2 yr of tagging and tag-recovery. In addition to the standard assumptions of multi-year tag-recovery models, it is necessary to assume that recruited animals have equal selectivity, pre-recruited animals become fully recruited in 1 or 2 yr, and the size groups experience the same natural mortality rate. Applicability of the model to the Tasmania southern rock lobster (Jasus edwardsii) fishery is evaluated using a simulation model and parameters based on data from the lobster fishery; assumptions are likely to be met and precision should be adequate if at least 1000 animals are tagged per year in each size group.

scholarly journals Sex-Specific Long-Term Trends in Length of Hospital Stay, Postmenstrual Age at Discharge, and Survival in Very Low Birth Weight Infants

Neonatology ◽  
2021 ◽  
pp. 1-9
Author(s):  
Matthias Fröhlich ◽  
Tatjana Tissen-Diabaté ◽  
Christoph Bührer ◽  
Stephanie Roll
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Hospital Stay ◽  
Very Low Birth Weight ◽  
Survival Rates ◽  
Length Of Hospital Stay ◽  
Mortality Rates ◽  
Vlbw Infants ◽  
Postmenstrual Age ◽  
Over Time

<b><i>Introduction:</i></b> In very low birth weight (&#x3c;1,500 g, VLBW) infants, morbidity and mortality have decreased substantially during the past decades, and both are known to be lower in girls than in boys. In this study, we assessed sex-specific changes over time in length of hospital stay (LOHS) and postmenstrual age at discharge (PAD), in addition to survival in VLBW infants. <b><i>Methods:</i></b> This is a single-center retrospective cohort analysis based on quality assurance data of VLBW infants born from 1978 to 2018. Estimation of sex-specific LOHS over time was based on infants discharged home from neonatal care or deceased. Estimation of sex-specific PAD over time was based on infants discharged home exclusively. Analysis of in-hospital survival was performed for all VLBW infants. <b><i>Results:</i></b> In 4,336 of 4,499 VLBW infants admitted from 1978 to 2018 with complete data (96.4%), survival rates improved between 1978–1982 and 1993–1997 (70.8 vs. 88.3%; hazard ratio (HR) 0.20, 95% confidence interval 0.14, 0.30) and remained stable thereafter. Boys had consistently higher mortality rates than girls (15 vs. 12%, HR 1.23 [1.05, 1.45]). Nonsurviving boys died later compared to nonsurviving girls (adjusted mean survival time 23.0 [18.0, 27.9] vs. 20.7 [15.0, 26.3] days). LOHS and PAD assessed in 3,166 survivors displayed a continuous decrease over time (1978–1982 vs. 2013–2018: LOHS days 82.9 [79.3, 86.5] vs. 60.3 [58.4, 62.1] days); PAD 40.4 (39.9, 40.9) vs. 37.4 [37.1, 37.6] weeks). Girls had shorter LOHS than boys (69.4 [68.0, 70.8] vs. 73.0 [71.6, 74.4] days) and were discharged with lower PAD (38.6 [38.4, 38.8] vs. 39.2 [39.0, 39.4] weeks). <b><i>Discussion/Conclusions:</i></b> LOHS and PAD decreased over the last 40 years, while survival rates improved. Male sex was associated with longer LOHS, higher PAD, and higher mortality rates.

scholarly journals An integrated tagging model to estimate mortality rates of Albemarle Sound – Roanoke River striped bass

2017 ◽  
Vol 74 (7) ◽  
pp. 1061-1076 ◽  
Author(s):  
Julianne E. Harris ◽  
Joseph E. Hightower
Keyword(s):  
Striped Bass ◽  
Stock Assessment ◽  
Mortality Rates ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Albemarle Sound ◽  
High Reward ◽  
Accuracy And Precision ◽  
Summer Mortality ◽  
Roanoke River

We developed an integrated tagging model to estimate mortality rates and run sizes of Albemarle Sound – Roanoke River striped bass (Morone saxatilis), including (i) a multistate component for telemetered fish with a high reward external tag; (ii) tag return components for fish with a low reward external or PIT tag; and (iii) catch-at-age data. Total annual instantaneous mortality was 1.08 for resident (458–899 mm total length, TL) and 0.45 for anadromous (≥900 mm TL) individuals. Annual instantaneous natural mortality was higher for resident (0.70) than for anadromous (0.21) fish due to high summer mortality in Albemarle Sound. Natural mortality for residents was substantially higher than currently assumed for stock assessment. Monthly fishing mortality from multiple sectors (including catch-and-release) corresponded to seasonal periods of legal harvest. Run size estimates were 499 000–715 000. Results and simulation suggest increasing sample size for the multistate component increases accuracy and precision of annual estimates and low reward tags are valuable for estimating monthly fishing mortality rates among sectors. Our results suggest that integrated tagging models can produce seasonal and annual mortality estimates needed for stock assessment and management.

Modeling data from double-tagging experiments to estimate heterogeneous rates of tag shedding in lake trout (Salvelinus namaycush)

1999 ◽  
Vol 56 (8) ◽  
pp. 1409-1419 ◽  
Author(s):  
Mary C Fabrizio ◽  
James D Nichols ◽  
James E Hines ◽  
Bruce L Swanson ◽  
Stephen T Schram
Keyword(s):  
Lake Trout ◽  
Survival Rates ◽  
Salvelinus Namaycush ◽  
Wild Fish ◽  
Retention Rates ◽  
Type I ◽  
Tag Retention ◽  
Tag Loss ◽  
Modeling Data ◽  
Tag Shedding

Data from mark-recapture studies are used to estimate population rates such as exploitation, survival, and growth. Many of these applications assume negligible tag loss, so tag shedding can be a significant problem. Various tag shedding models have been developed for use with data from double-tagging experiments, including models to estimate constant instantaneous rates, time-dependent rates, and type I and II shedding rates. In this study, we used conditional (on recaptures) multinomial models implemented using the program SURVIV (G.C. White. 1983. J. Wildl. Manage. 47: 716-728) to estimate tag shedding rates of lake trout (Salvelinus namaycush) and explore various potential sources of variation in these rates. We applied the models to data from several long-term double-tagging experiments with Lake Superior lake trout and estimated shedding rates for anchor tags in hatchery-reared and wild fish and for various tag types applied in these experiments. Estimates of annual tag retention rates for lake trout were fairly high (80-90%), but we found evidence (among wild fish only) that retention rates may be significantly lower in the first year due to type I losses. Annual retention rates for some tag types varied between male and female fish, but there was no consistent pattern across years. Our estimates of annual tag retention rates will be used in future studies of survival rates for these fish.

Impacts of recolonizing gray wolves (Canis lupus) on survival and mortality in two sympatric ungulates

2018 ◽  
Vol 96 (7) ◽  
pp. 760-768 ◽  
Author(s):  
J.A. Dellinger ◽  
C.R. Shores ◽  
M. Marsh ◽  
M.R. Heithaus ◽  
W.J. Ripple ◽  
...  
Keyword(s):  
Canis Lupus ◽  
Mule Deer ◽  
Survival Rates ◽  
Odocoileus Hemionus ◽  
Mortality Rates ◽  
Adult Survival ◽  
Mortality Data ◽  
Gray Wolf ◽  
Gray Wolves ◽  
Large Predators

There is growing recognition that humans may mediate the strength and nature of the ecological effects of large predators. We took advantage of ongoing gray wolf (Canis lupus Linnaeus, 1758) recolonization in Washington, USA, to contrast adult survival rates and sources of mortality for mule deer (Odocoileus hemionus (Rafinesque, 1817)) and white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) in areas with and without wolf packs in a managed landscape dominated by multiple human uses. We tested the hypothesis that the addition of wolves to the existing predator guild would augment predator-induced mortality rates for both ungulates. Source of mortality data from adult mule deer and white-tailed deer, respectively, revealed that wolf-related mortality was low compared with that inflicted by other predators or humans. Predator-caused mortality was largely confined to winter. There was little effect of wolf presence on adult deer mortality rates, and there was no difference in mortality between the two deer species relative to wolf-free or wolf-occupied sites. Although this study occurred early in wolf recovery in Washington, our results differ from those demonstrated for gray wolves in protected areas. Thus, we encourage further investigation of effects of direct predation by recolonizing large carnivores on prey in human-dominated landscapes.

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