Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 17 of 17 for “"catchability"”.
-
Multi-Species Models of Time-Varying Catchability in the U.S. Gulf of Mexico
The catchability coefficient is used in most marine stock assessment models, and is usually assumed to be stationary and density-independent. However, recent research has shown that these assumptions are violated in most fisheries. Violation of these assumptions will cause underestimation of stock …
-
Sampling Attributes of Puerto Rico Stream Fishes: Bias, Selectivity, and Environmental Influences
… would be enhanced by an understanding of gear catchability, a standardized sampling method, and accurate population estimates. My primary objectives for this study were to (1) quantitatively describe gear efficiency and selectivity relationships to estimate stream fish populations in Puerto …
-
Evaluating Alberta’s Fall Index Netting Protocol for Assessing Northern Pike (Esox lucius) Populations
… to Northern Pike population density, 2) FIN catchability was unrelated to Northern Pike density, 3) FIN catch size distributions were predictably related to Northern Pike sizes, 4) FIN catch rates were related to angler catch rates, and 5) FIN monitoring was economically efficient. Continued …
-
An evaluation of the removal method for estimating benthic populations and diversity
… benthic sample populations and species catchability. The removal sampling method was compared to Modified Hess, Surber, and Kicknet sampling methods, and gave consistently higher and less variable estimates than other methods. Taxa showing the lowest catch abilities included the …
-
An evaluation of systematic error in the estimation of fish population size
… to mortality of marked fish, an increased catchability of marked fish due to marking, and the ability of fish to learn to avoid capture gear. Different gear combinations and use of different estimation models had no significant effect on the accuracy of estimates obtained. The study was …
-
A comparison of growth rates of coarse fish in gravel-pit lakes in south-east England and of population structure in selected lakes
… Catch method to allow for mortality or change in catchability of marked fish is proposed. These models and methods of marking and tagging fish are critically appraised. A notable criticism is that marked fish cannot be regarded as behaving in the same way as unmarked individuals.
-
Space Use and Survival of White-Tailed Deer in a Disturbance-Driven System Containing a Restored Apex Predator
… female deer impacted survival, influencing prey catchability and potentially buffering prey populations against cycles of predation.
-
Deep water parapagurid hermit crabs: their distribution, abundance, population structure and associations in the Southern Benguela
… and sandy sediments (45.68 kg.km⁻²). Overall catchability (mean = 43.35%) has remained constant over the 23 years (R2 = 0.13) with a slight trend towards increasing catchability over time, which may correspond to a change in survey design.
-
Analysis of catchable trout fisheries management by computer simulation
… Estimates of expected angling pressure ru1d catchability coefficients of each species stocked are of primary importance because of their considerable effect on other system components. A user must have a sound objective before deciding where, when, which species, and how many fish to plant. …
-
ESTIMATION OF MORTALITY RATES FOR THE GULF MENHADEN STOCK AND REFERENCE POINT IMPLEMENTATION FOR THE FISHERY
… distribution to estimate natural mortality, catchability, and the overdispersion factor parameters. I established a Base model and n = 17 sensitivity models for robustness. I estimated a constant instantaneous natural mortality of 1.08 y<sup>-1</sup> with 95% confidence intervals of 1.04 …
-
A general population dynamics theory for largemouth bass fisheries
… the possible effects of exploitation on average catchability and population structure. Methods for calculation of optimal length limits and production and yield were illustrated for simple cases. Use of the full power of the model, however, must await more detailed description of factors …
-
Affordances In The Design Of Virtual Environments
… by examining three affordances: passability, catchability, and flyability. The experimental design involved four factors for each of the three affordances and was implemented as a 2 [subscript IV] [superscript 4-1] fractional factorial design. The results demonstrated that providing affording …
-
Determinants for the Timing of Escapement From the Sockeye Salmon Fishery of the Copper River, Alaska: A Simulation Model
… area from catch and escapement data.</p> <p>The catchability coefficients (q), derived from the reconstructed populations were found to vary within season and between seasons. The relation between q and effort was attributed to a highly competitive fishery.</p> <p>The difference found between the …
-
Propagation and monitoring of freshwater mussels released into the Clinch and Powell rivers, Virginia and Tennessee
… free-released mussels (untagged, tagged) had low catchability. Mussels released at Horton Ford, Clinch River, exhibited significantly faster growth. Horton Ford is the most suitable site, while environmental conditions at Fugate Ford, Powell River, are deemed unsuitable for mussel restoration and …
-
Development and application of a multistate model to the northern subpopulation of loggerhead sea turtles
… states violate the assumption of equal catchability in the available single state mark-recapture models. Therefore, a multistate mark- recapture model originally developed for leatherback sea turtles was applied to the Bald Head Island loggerhead population. Multistate modeling provides …
-
Aspects of the sustainability of creel fishing for Norway lobster, Nephrops norvegicus (L.), on the west coast of Scotland
… on how the biology of Nephrops affects its catchability in creels, as well as assessing the environmental impacts of the Nephrops creel fishery. A smaller study relating to the physiological effects of the capture and transport of live creel-caught Nephrops, has also been undertaken. …