Two dimensional stocks of fish can be assessed with methods that mimic the analysis of research survey data but that use commercial catch-effort data. This finite population approach has scarcely been used in fisheries science though it brings about very large sample sizes of local fish density with models of only moderate levels of complexity. The extracted information about the status of the stock can be interpreted as biomass indices. Statistical inference on finite populations has been the locus of a highly specialized branch of sampling-distribution inference, unique because observable variables are not considered as random variables. If statistical inference is defined as "the identification of distinct sets of plausible and implausible values for unobserved quantities using observations and probability theory" then it is shown that Godambe's paradox implies that the classical finite populations approach is inherently contradictory as a technique of statistical inference. The demonstration is facilitated by the introduction of an extended canonical form of an experiment of chance, that apart from the three components identified by Birnbaum, also contains the time at which the experiment is performed. Realization of the time random variable leaves the likelihood function as sole data-based mathematical tool for statistical inference, in contradiction with sampling-distribution inference and in agreement with direct-likelihood and Bayesian inference. A simple mathematical model is introduced for biomass indices in the spatial field defined by the fishing grounds. It contains three unknown parameters, the natural mortality rate, the probability of observing the stock in the area covered by the fishing grounds, and mean fish density in the sub-areas where the stock was present. A new theory for the estimation of mortality rates is introduced, using length frequency data, that is based on the population ecology analogue of Hamilton-Jacobi theory of classical mechanics. The family of equations require estimations of population growth, individual growth, and recruitment pattern. Well known or new techniques are used for estimating parameters of these processes. Among the new techniques, a likelihood-based geostatistical model to estimate fish density is proposed and is now in use in fisheries science (Roa-Ureta and Niklitschek, 2007, ICES Journal of Marine Science 64:1723-1734), as well as a new method to estimate individual growth parameters (Roa-Ureta, In Press, Journal of Agricultural, Biological, and Environmental Statistics). All inference is done only using likelihood functions and approximations to likelihood functions, as required by the Strong Likelihood principle and the direct-likelihood school of statistical inference. The statistical model for biomass indices is a hierarchical model with several sources of data, hyperparameters, and nuisance parameters. Even though the level of complexity is not low, a full Bayesian formulation is not necessary. Physical factors, mathematical manipulation, profile likelihoods and estimated likelihoods are used for the elimination of nuisance parameters. Marginal normal and multivariate normal likelihood functions, as well as the functional invariance property, are used for the hierarchical structure of estimation. In this manner most sources of information and uncertainty in the data are carried over up the hierarchy to the estimation of the biomass indices.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2006. / Title from title screen (site viewed on Feb. 6, 2007). PDF text: xii, 196 p. : ill., maps. UMI publication number: AAT 3220344. Includes bibliographical references. Also available in microfilm and microfiche format.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 110-119). Also available on the World Wide Web.

Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Ecology and Evolution." Includes bibliographical references (p. 56-76).

Thesis (M. Sc.)--York University, 2007. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 83-99). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004 & res_dat=xri:pqdiss & rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation & rft_dat=xri:pqdiss:MR31989.

Darbo aktualumas: Mokslinėje literatūroje pateikiama daug duomenų ir informacijos apie žuvų auginimo ypatumus žuvininkystės ūkiuose auginat žuvis pramoniniu būdu. Sodybiniai vandens telkiniai savo ruožtu įrengiami ir žuvys jose auginamos bei veisiamos šių telkinių savininkų nuožiūra. Trūksta mokslinių tyrimų ir metodinės literatūros analizuojančios sodybinių vandens telkinių įrengimo bei jų pritaikymo mėgėjiškos akvakultūros vystymui, problematiką, todėl ši sritis nusipelno išsamesnės mokslinės analizės. Darbo tikslas: Išanalizuoti sodybinių vandens telkinių įrengimo, jų priežiūros bei žuvų auginimo sodybiniuose vandens telkiniuose ypatumus. Darbo uždaviniai: 1. Apibrėžti dirbtinių vandens telkinių įrengimo teisinį reglamentavimą, atlikti sodybinių vandens telkinių įrengimo projektų vertinimą. 2. Aprašyti sodybiniuose vandens telkiniuose auginamas žuvų rūšis ir aptarti jų auginimo sodybiniuose vandens telkiniuose specifiką. 3. Atlikti vandens telkinių vandens fizinių savybių, cheminės sudėties ir mikrobiologinius tyrimus bei pateikti sodybinių vandens telkinių vandens kokybės vertinimą. 3. Nustatyti su sodybinių vandens telkinių priežiūra, žuvų veisimu ir auginimu susijusias problemas bei pateikti rekomendacijas problemų sprendimui. Išvados: 1. Tiriami sodybiniai vandens telkiniai įrengti pagal suderintus nesudėtingus vandens telkinių įrengimo projektus prisilaikant LR Aplinkos apsaugos įstatyto ir kitų teisės aktų reikalavimų. Sodybinių vandens telkinių įrengimo metu... [toliau žr. visą tekstą] / It is hard to imagine a Lithuanian country district with no pond. Recently the owners of the ponds more and more often select the homestead ponds which are well adapted to the amateurish fish breeding, growing and recreation. It is important, while setting such homestead ponds, to understand the biology of separate fish breeds and to realize the pond as individual and complex ecosystem. Homestead ponds and the water quality need to satisfy biological features of fish and to secure their wellness and nutritional quality. This demands a good knowledge and appropriate competency of the owners at such spheres as pond equipment, fish breeding, fish growing, fish additional feeding, evaluation of water quality and etc. Scientific literature supplies plenty of data and information about peculiarities of fish growing at the fishery farms where the fish are cultured in an industrial way. The homestead ponds are set and the fish are grown and bred at the discretion of the owners. This sphere deserves particular scientific analysis because of the lack of scientific investigations and methodological literature which analyzes the topic of pond equipment and adjustment for the development of amateurish aquaculture. The aim of this study is to analyze the peculiarities of pond equipment, observation and fish growing in the ponds. In order to reach the goal several tasks which include definition of the juridical regulation of pond equipment and evaluation of pond equipment projects were made... [to full text]

The fish processing industry is actively seeking for alternative methods of shelf life preservation and marketability of fresh fish, while at the same time economizing on energy costs. Two methods which fulfill both objectives are modified atmosphere packaging (MAP) and glucose oxidase (GOX)/Glucose dipping solutions. MAP is the packaging of perishable products in an atmosphere other than that of air and is used for the shelf life extension of beef, pork, fruits, vegetables and bakery products. GOX, either alone or in conjunction with MAP has the potential for shelf life extension of fresh fish. / The objectives of this study were to determine the combined effect of glucose oxidase/glucose or gluconic acid dipping solutions and modified atmosphere packaging in conjunction with refrigeration on the shelf life extension of mackerel and cod. / This study has shown that the shelf life of fresh fish can be extended through the combined use of MAP/dipping solutions and refrigeration. This novel process of "dipping" in GOX solution in conjunction with modified atmosphere packaging (MAP) will have a significant effect in the area of fish hygiene and will minimize fish losses incurred through spoilage.

The combined effect of various gas packaging atmospheres (air, vacuum and gas packaging), films of different oxygen transmission rate (OTR) and storage temperature (4 and 12°C) were investigated on the shelf-life and safety of flesh rainbow trout fillets. / Preliminary studies were done to determine the optimum packaging atmospheres to maintain the bright pink color of trout packaged in a high gas barrier film. Both vacuum and gas packaging (85% CO2:15%N2) resulted in the longest shelf-life (~28 days) in terms of color at 4°C. Based on these optimum gas atmospheres for color, shelf-life studies were performed at both refrigerated and temperature abuse conditions (12°C). / Challenges studies were also done with Listeria monocytogenes and Clostridium botulinum type E, two psychrotrophic pathogens of concern in modified atmosphere packaged (MAP) fish. / Subsequent studies were done to determine the effect of various levels of headspace oxygen (0--100%, balance CO2) or film OTR on the time to toxicity in trout stored at 12°C. (Abstract shortened by UMI.)

Value-added trout burgers and trout wontons were prepared from minced trout trimmings, oats, dried onion flakes, white pepper, cayenne pepper, garlic powder, soy sauce, spice mix and eggs. The trout burgers were coated with crushed cornflakes and then partially cooked (2 min at 140ºC) or frilly cooked (5 min at 140ºC) in hot oil. Similar fillings were used to prepare trout wontons by wrapping the mixture with Chinese wonton dough and 2 products were made: raw wonton (uncooked) and fried wonton (fried for 8 min at 140ºC). / Storage trials were performed on raw and fried trout wontons (a w 0.98--0.95, pH 6.5), and partially and fully cooked trout burgers (aw 0.97--0.96, pH 6.4). Products were packaged in air and under various modified atmospheres (MAP), and stored at 4 and 12ºC. A microbiological shelf-life of >28 days was possible for the cooked trout burgers and fried wontons stored at 4ºC. In general, the microbiological shelf-life preceded the sensory shelf-life. / Subsequent challenge studies were done to address the safety concerns associated with MAP food. All products were inoculated with 102 CFU/g of Listeria monocytogenes and 102 spores/g of Clostridium botulinum type E spores. Gas packaging with 80% CO2 (balance N2) inhibited the growth of L. monocytogenes in products stored at 4ºC. However, counts of L. monocytogenes increased in all other packaging conditions. In challenge studies with C. botulinum type E, toxin was not detected in any products after 28--60 days.

The introduction of trout has been implicated in the declines in native fish fauna in New Zealand and worldwide. Since the introduction of brown (Salmo trutta) and rainbow (Oncorhynchus mykiss) trout to New Zealand in 1867, their distribution has spread and they have been implicated in the fragmentation of native fish distributions, particularly native non-migratory galaxiids. However, in the Upper Waimakariri basin the co-occurrence of trout and galaxiid populations is relatively common, even in streams where trout reach sizes known to be piscivorous. To investigate mechanisms that may regulate trout and galaxiid co-occurrence, I investigated differences in antipredator behaviour and growth rate between stream types with varying levels of trout presence. Using quantitative survey data collected between 1997 and 2006, I found that trout abundance was low and varied annually in frequently disturbed sites compared their high abundance in stable streams. This finding was used to classify streams into three population types, barrier (trout absent), disturbed (trout presence intermittent) and sympatric (constant trout presence). Using this classification, I tested the effects of trout chemical cues on galaxiid activity and refuge use in artificial channels. There were no differences in activity or refuge use between trout odour and there were no effects of population type or galaxiid size during both the day and the night. Using otolith weight-fish length relationships in galaxiids collected from each population type, I found that galaxiid growth rate was higher in disturbed streams than in stable streams either with or without trout. An experiment manipulating trout size and presence, over two months in a natural stream, found galaxiids from treatments without trout grew slower than those with trout. Slow growth rates in galaxiids above trout-migration barriers and in sympatry, combined with low growth rates in treatments without trout suggest that the mechanisms that regulate galaxiid growth are more complex than previously thought.