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In the present study the effects of characteristic freezing times and storage time at -22°C on the quality of the adductor muscle of post-rigor scallops (Pecten maximus)and gilthead seabream fillets (Sparusa urata) were studied in regard to the integrity of muscle structure, myofibrillar protein denaturation and aggregation, lipid degradation, texture and sensory changes. This information would be useful for achieving optimal conditions for freezing these species and assessing their quality during frozen storage for commercial purposes. Scallop muscles and gilthead seabream fillets were frozen individually with characteristic freezing times that can be met in commercial practice of freezing seafoods. After freezing, the samples were thawed and their quality was evaluated. Fresh samples were analyzed as controls. Intermediate characteristic freezing times (i. e. 89 and 49 minutes for scallop muscles and 74 minutes for gilthead seabream fillets) caused more damage to cell structure of both species than the shorter and longer characteristic freezing times tested. Short characteristic freezing times (i. e. 19 minutes for scallop muscles, and 2 and 18 minutes for gilthead seabream fillets) reduced the thawing losses of both species compared to the longer characteristic freezing times (. e. 235 to 1000 minutes for scallop muscles, and 640 minutes for gilthead seabream fillets) tested. Freezing at short characteristic freezing times produced raw fillets similar in texture to the fresh fillets. Therefore, short characteristic freezing times (equal to or less than 19 minutes) are beneficial for freezing both species. Scallop muscles and gilthead seabream fillets were kept frozen for up to 301 and 340 days, respectively. Sampling was carried out at regular intervals on fresh and stored frozen samples. Storage time affected the integrity of infra-cellular organelles, reduced the water holding capacity, caused structural changes to myofibrillar proteins and affected the sensory attributes of both species. Frozen scallop muscles were in acceptable eating condition after a storage period of ten months, with most of the changes in bio-chemical and physical properties being pronounced after three months of storage. Based on the changes in taste scores versus storage time, it was assessed that the practical storage life of frozen gilthead seabream fillets was circa 5 to 6 months Cat+-ATPase activities for scallop muscles and a linear model that combines free fatty acids, peroxide values and protein content in centrifugal tissue fluids for gilthead seabream fillets, may be reliable methods for industry to use for assessing their quality during long term storage at -22°C.

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<p>Scallops, a family of swimming bivalve mollusks, have dozens of eyes arrayed along the edges of their valves. Relatively little is known about the form and function of these unusual eyes. To learn more about them, we studied the visually influenced behavior of scallops, as well as the morphology and spectral sensitivity of their eyes. Of particular interest was whether or not the simple neural architecture of these animals constrains the number of visually-influenced behaviors they can perform. We were also interested to learn whether scallop eyes, despite providing relatively poor visual acuity, show optical refinements, such as corrections for spherical and chromatic aberration, that are known from the eyes of animals with better vision. In the following dissertation, Chapter 2 discusses the visually-influenced behaviors of scallops. It has been argued that bivalve mantle eyes only act as predator-detectors, but the behavioral trials described in this chapter suggest that vision may serve additional purposes in scallops. For example, it was found that visual cues relating to flow conditions may influence scallop feeding behavior. Chapter 3 presents a comparative study of scallop eye morphology. Here, it is found that eye morphology varies considerably between scallop species and that highly mobile scallops have better vision than less mobile or immobile species. Evidence is also presented that one of the two scallop retinas may perform tasks of similar importance to all species, such as predator detection, while the other retina may perform tasks more important to mobile species, such as those associated with the visual detection of preferred habitats. Chapter 4 investigates the spectral sensitivity of the two retinas in the mantle eyes of two scallop species. It is found that there is both inter- and intra-specific variation in scallop spectral sensitivity and that color perception in scallops may be influenced by both environmental light conditions and chromatic aberration caused by their lens. The research in this dissertation provides insight into how vision functions in animals that, like scallops, have a vast number of eyes, but a limited capacity for neural processing. Despite such limitations, it is evident that scallops display a wide range of visual behaviors and have eyes with highly-refined optics.</p> / Dissertation

<p> Proposed theories concerning the nature and mode of formation of limestone scallops are examined. Some progress is made toward a purely theoretical understanding. Scallop formation is simulated by generation on blocks of Plaster of Paris in a laboratory flume under known and controlled conditions and the relationships between the resulting features, the generating conditions and the base material examined. Field Evidence both confirms these relationships and reveals other unsuspected factors. The similarity between these features and others found on ablating snow surfaces is investigated and the same laws found to apply. </p> / Thesis / Doctor of Philosophy (PhD)

Scallops have traditionally been blast or sharp frozen. This study compared the quality of at-sea cryogenically frozen scallops with fresh and mechanically frozen scallops. A liquid CO₂ batch freezer was installed on-board the scallop boat. Samples were analyzed for microbiological, physical, chemical and sensory qualities. Sample types included fresh scallops, mechanically frozen scallops and 4 hr and 24 hr (on ice) cryogenically frozen scallops. The thaw loss mean of 4 hr cryogenically frozen scallops was 2.41 percent compared to means of 4.21 percent for 24 hr (on ice) cryogenically frozen scallops and mechanically frozen scallops, P < 0.0001. Cook loss for the 4 hr cryogenic frozen scallop was also reduced (P < 0.01) by 27 percent when baked. Cook method did not affect cook loss. Color measurements on the CIE L* a* b* scale did not differ significantly for raw or baked scallops. Instron peak force measurements had a very high standard error and therefore were not be analyzed statistically. The 4 hr cryogenically frozen scallops met the French Moisture/Protein ratio test standard of 5 (P > 0.02) but higher ratios were observed for 24 hr (on ice) cryogenically frozen scallops and mechanically frozen scallops. Scallops meeting this standard have greater export potential and the ability to attract high value markets. Variations observed in proximate composition were minor and may be due to biological factors. Sensory panelists found a significant difference (P < 0.01 to P < 0.05) among the randomly presented pairs of scallops. Over a 5 month storage period, the sensory characteristics of odor and taste of the cryogenically frozen scallops diminished and the mechanically frozen scallops were consistently scored higher. Mechanically frozen scallops had significantly lower cfu/gm for aerobic, psychrotrophic and coliform counts compared to fresh and cryogenically frozen scallops. The 4 hr cryogenically frozen scallop had lower thaw and cook loss which could have a significant economic and nutritional significance. Mechanically frozen scallops had a lower microbiological population and frozen storage for 8 months did not affect its taste or odor. Improved Sanitation and process control could establish cryogenically frozen scallops as a premium product. / Master of Science

To assess the spatial distribution of nutrient wastes around an open-water integrated fish/mollusk/kelp farm in-situ kelp bioassays were employed. Growth rates were measured over a four-month growing season and used as a proxy for relative nutrient concentrations. Seasonality and depth effects on growth rate were also assessed. Growth around the pens was 0.20 cm • day-1 higher than at the control, and reached a maximum of 1.4 cm • day-1. Optimal growth was achieved at 8 m. Growth at 8 m was significantly higher by 1.5 cm • day-1 compared to surface waters at 2 m. Early spring had the highest growth rates with a peak of 1.4 cm • day-1 recorded on June 21. This study re-iterates the fundamental benefits of IMTA and shows the potential of in-situ assay as an alternative to error-prone and costly water sampling to asses nutrient status in water. / Graduate

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