Bias in survival estimates from tag-recovery models where catch-and-release is common, with an example from Atlantic striped bass (Morone saxatilis)

2000 ◽  
Vol 57 (5) ◽  
pp. 886-897 ◽  
Author(s):  
David R Smith ◽  
Kenneth P Burnham ◽  
Desmond M Kahn ◽  
Xi He ◽  
Cynthia J Goshorn ◽  
...  
Keyword(s):  
Striped Bass ◽  
Model Averaging ◽  
Morone Saxatilis ◽  
Weighted Average ◽  
Reporting Rate ◽  
Parameter Estimates ◽  
Regulatory Change ◽  
Applied Model ◽  
Catch And Release ◽  
Recovery Models

Survival rate is underestimated when tag-recovery models include tags recovered from harvested and caught-and-released fish. The magnitude of the bias depends on tag-recovery rate, proportion of catch released alive, and reporting rate; changes in these factors over time confound temporal changes in survival. The bias is of potential concern for any tagging study where catch-and-release is mandatory or practiced voluntarily. The bias is of concern particularly for the Atlantic striped bass (Morone saxatilis) tagging study where catch-and-release is common and anglers commonly remove the tag upon capture regardless of fish disposition. Biased estimates of striped bass survival did not change with changes in harvest regulation during the mid-1990s. However, bias-adjusted estimates of survival showed a decrease, which corresponds to the regulatory change made in 1995. Year-specific reporting rate is critical to bias adjustment, underscoring the need for reward tags in fish tagging studies. Tag-recovery modeling allows for a diverse set of models, each of which can produce widely different estimates with far-reaching consequences for management. We applied model averaging to base inference on a weighted average of parameter estimates and to account for model selection uncertainty.

Diagnostics for multiyear tagging models with application to Atlantic striped bass (Morone saxatilis)

2001 ◽  
Vol 58 (9) ◽  
pp. 1716-1726 ◽  
Author(s):  
Robert J Latour ◽  
John M Hoenig ◽  
John E Olney ◽  
Kenneth H Pollock
Keyword(s):  
Striped Bass ◽  
Goodness Of Fit ◽  
Model Performance ◽  
Morone Saxatilis ◽  
Total Mortality ◽  
Information Criterion ◽  
Diagnostic Procedures ◽  
Hudson River ◽  
Reporting Rate ◽  
Data Set

Information on age- and year-specific survival can be obtained from multiyear tagging data using one of three classes of tag recovery models. Two of the model types yield information on total survival, while the third allows separation of total mortality into its fishing and "natural" components if information on the tag reporting rate is available. The performance of each class is usually assessed using goodness-of-fit tests, Akaike's information criterion, and similar measures. However, we propose that examination of model residuals is also important for the evaluation of model performance and contend that at least four types of problems are potentially detectable via patterns in residuals. Those presented in this paper include nonmixing of newly tagged animals, emigration of older animals, cohort effects associated with initial tag-induced mortality or tag shedding, and a change in the natural mortality rate. We present the diagnostic procedures by analyzing a hypothetical tagging data set and discuss the various constraints inherent to the residuals of each class of models. The diagnostic procedures are also used to evaluate striped bass tagging (Morone saxatilis) data from the Hudson River and Chesapeake Bay.

Prerelease Stratification in Tag-Recovery Models with Time Dependence

1993 ◽  
Vol 50 (3) ◽  
pp. 535-541 ◽  
Author(s):  
Robert M. Dorazio
Keyword(s):  
Striped Bass ◽  
Statistical Power ◽  
Statistical Significance ◽  
Morone Saxatilis ◽  
Linear Combinations ◽  
Recovery Rates ◽  
Group Interactions ◽  
Average Survival ◽  
Sources Of Variation ◽  
Recovery Models

A statistical model is developed for estimating time-dependent survival and recovery rates of tagged populations that are stratified into groups at release. For populations of fish, the groups might include different sexes or stocks, or they might be distinguished by the location or method of capture. In the model developed here, survival and recovery rates are formulated as linear combinations of parameters that include the effects of time, group, and time–group interactions. Methods of testing the statistical significance of these potential sources of variation are described and illustrated with the recoveries of different stocks of anadromous striped bass (Morone saxatilis). For the striped bass data, elimination of time- and stock-specific sources of variation substantially improved the precision of survival estimates without introducing important bias. During 1988–89 the average survival of both stocks was 0.78 (SE = 0.04). Calculations of statistical power indicate that stock-specific differences in survival of ± 0.2 could have been detected about 50% of the time, given the low rates of recovery and numbers of fish released.

Biology and Management of Inland Striped Bass and Hybrid Striped Bass

2013 ◽  
Keyword(s):  
Striped Bass ◽  
Reporting Rate ◽  
Integrated Analysis ◽  
Natural Mortality ◽  
Relative Impact ◽  
Catch And Release ◽  
Tag Loss ◽  
Abundance Estimates ◽  
Large Systems ◽  
Optimal Approach

<em>Abstract</em>.—Striped bass <em>Morone saxatilis </em>in inland reservoirs play an important role ecologically and in supporting recreational fishing. To manage these populations, biologists need information about abundance and mortality. Abundance estimates can be used to assess the effectiveness of stocking programs that maintain most reservoir striped bass populations. Mortality estimates can indicate the relative impact of fishing versus natural mortality and the need for harvest regulation. The purpose of this chapter is to evaluate tagging studies as a way of obtaining information about abundance and mortality. These approaches can be grouped into three broad categories: tag recapture, tag return, and telemetry. Tag-recapture methods are typically used to estimate population size and other demographic parameters but are often difficult to apply in large systems. A fishing tournament can be an effective way of generating tagging or recapture effort in large systems, compared to using research sampling only. Tag-return methods that rely on angler harvest and catch and release can be used to estimate fishing (<EM>F</EM>) and natural (<EM>M</EM>) mortality rates and are a practical approach in large reservoirs. The key to success in tag-return studies is to build in auxiliary studies to estimate short-term tagging mortality, short- and longterm tag loss, reporting rate, and mortality associated with catch and release. <EM>F </EM>and <EM>M </EM>can also be estimated using telemetry tags. Advantages of this approach are that angler nonreporting does not bias estimates and fish with transmitters provide useful ecological data. Cost can be a disadvantage of telemetry studies; thus, combining telemetry tags with conventional tag returns in an integrated analysis is often the optimal approach. In summary, tagging methods can be a powerful tool for assessing the effectiveness of inland striped bass stocking programs and the relative impact of fishing versus natural mortality.

Emamectin benzoate is a safe and effective anthelmintic against coelomic nematode Philometra rubra in striped bass Morone saxatilis

2020 ◽  
Vol 142 ◽  
pp. 47-53
Author(s):  
K Béland ◽  
G Séguin ◽  
S Lair
Keyword(s):  
Mortality Rate ◽  
Striped Bass ◽  
High Mortality ◽  
Morone Saxatilis ◽  
Treatment Results ◽  
Emamectin Benzoate ◽  
Once Daily ◽  
Fish Hatchery ◽  
Parasitic Burden

An unusually high mortality rate due to verminous (Philometra rubra) coelomitis was documented in wild-hatched striped bass Morone saxatilis raised in a fish hatchery as part of a stock restoration program. To decrease the parasitic burden and therefore potentially minimize mortality, the effectiveness of 2 different anthelmintics was evaluated. Two trials were conducted on wild-collected fingerlings naturally infected by P. rubra. In 2006, 144 yearling fish were randomly assigned to 4 experimental groups: (1) levamisole (Levasol®) at 2 mg l-1 via immersion for 8 h once weekly for 3 wk; (2) levamisole at a dose of 2.5 mg kg-1 biomass via feed once daily for 7 d; (3) emamectin benzoate (Slice®) at a dose of 0.05 mg kg-1 biomass via feed once daily for 7 d; and (4) control. Emamectin successfully eliminated live nematodes in 84.9% of the fish, whereas the administration of levamisole, either via immersion or feed, was not successful in significantly reducing the number of live P. rubra. In 2007, the administration of the same dosage of emamectin to approximately 1000 naturally infected yearling striped bass was associated with a 100% mortality rate of P. rubra in the 30 fish randomly examined 5 wk after the beginning of the treatment. Results of these trials indicate that, at the dosage used, the administration of emamectin at the end of the summer is safe for striped bass yearlings and considerably reduces the prevalence and intensity of the infection by this parasite.

Feeding ecology of early life stages of striped bass (Morone saxatilis) along an estuarine salinity-turbidity gradient, St. Lawrence Estuary, Canada

2019 ◽  
Vol 41 (4) ◽  
pp. 507-520 ◽  
Author(s):  
L Vanalderweireldt ◽  
P Sirois ◽  
M Mingelbier ◽  
G Winkler
Keyword(s):  
Striped Bass ◽  
Feeding Ecology ◽  
Early Life ◽  
Morone Saxatilis ◽  
Early Summer ◽  
Gut Contents ◽  
Life Stages ◽  
Early Life Stages ◽  
Lawrence Estuary ◽  
Feeding Niche

Abstract After being extirpated from the St. Lawrence River in the 1960s, striped bass (Morone saxatilis) were reintroduced to the estuary in 2002 and by 2008, they were naturally reproducing. To document the habitat use and feeding ecology of this reintroduced population, we examined the gut contents of 333 larvae and juveniles. Samples were collected in four estuarine habitats in 2014: the upstream freshwater section (UP), the oligohaline (O-ETM) and the mesohaline (M-ETM) estuarine turbidity maximum zones, and the downstream polyhaline section (DOWN). In June, pelagic larvae developed in the UP and the O-ETM, feeding mainly on copepods such as Eurytemora affinis. The O-ETM exhibited better suitable feeding conditions compared to the UP, likely due to the presence of Bosmina sp. as a primary prey. After July, striped bass shifted to larger prey items, consuming mainly dipteran pupa in upstream littoral habitats and gammarids and mysids in downstream habitats. In the early summer, the UP provided a high-quality nursery habitat and as the season progressed, the smallest juveniles dispersed downstream and improved their feeding success by exploiting a new feeding niche. This observation suggests that being distributed throughout the estuary may increase the potential survival of striped bass early life stages.

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