Hatcheries whose purpose is to provide for a recreational fishery must minimize impacts on wild fishes. Management to reduce hatchery and wild interactions is especially important on river systems that contain Endangered Species Act (ESA) listed species. I examined adult hatchery summer steelhead, Oncorhynchus mykiss, behavior, current management and a...
Cyanobacteria are photosynthetic bacteria capable of producing toxins, including complex cyclic peptides called microcystins. Hazardous cyanobacterial blooms are an emerging public health concern and are monitored throughout Oregon in various recreational and drinking water bodies. Oregon has been proactive and responsive to the problems associated with toxic cyanobacterial blooms, but...
A number of steelhead (Oncorhynchus mykiss) populations are at risk throughout Oregon, including five populations that are federally listed as threatened or endangered. However, little is known about behavior and survival of these fish as they transition from freshwater to seawater. We investigated whether estuarine survival varies on a temporal...
Understanding the origin and nature of intra specific biodiversity enables us to better conserve and manage animal populations. Biological diversity is seen at different scales and for different traits such as behavior, morphology, physiology, and life history. Behavior is especially important since behavioral changes are believed to precede changes in...
The collagen content and composition of collagens in
different age classes of shrimp were determined. Their
physical and chemical characteristics were investigated.
The interrelationship of shrimp size and muscle collagen
content to raw and cooked meat yield was established.
Total collagen content for three lots of round shrimp
with weights...
Proteases present in shrimp processing waste are factors in the
technology of shrimp. The distribution of proteolytic activity in
shrimp parts was determined using hemoglobin and casein as substrates. The effects of various parameters upon activity of proteases
in the inedible portion were determined using muscle protein as a
substrate....
The effects of ambient temperature storage on the chemical
and nutritional characteristics of phosphoric and sorbic acid-stabilized
fish autolysates were determined. Variations in sample
composition due to autolysis, deboning, and acidification were also
evaluated.
Autolysates of English sole (Parophrys vetulus), true cod
(Gadus macrocephalus), Dover sole (Microstomus pacificus), and
orange...
Chilling (2-4°C) (10 min) in a solution containing 10% condensed
phosphate, 5% potassium sorbate, and 0.9% citric acid (pH 6.7)
stabilized round shrimp to microbial spoilage. This treatment procedure
allowed refrigerated storage of round shrimp eliminating the
need for ice and the accompanying deteriorative effects of water
absorption and protein...
The abundance and low fat content of Pacific whiting
support Its use for the production of surimi. The
degradation of muscle proteins by myxosporidian secreted
proteinase(s) has been associated with its soft texture.
High residual activity is retained through the washing
process used in the production of surimi and precludes...
A suitable method for the utilization of shrimp processing waste was investigated. The shrimp waste, which consisted of shell, viscera, and residual meat particles, was dried into a pink meal. This meal contained 5.4 percent moisture, 23.5 percent ash, 4. 1 percent crude lipid, 36. 3 percent actual protein, and...
The biochemical and organoleptic changes that took place in
raw whole Pacific shrimp and in the cooked meat during eight days
of iced storage were investigated.
A steady increase of both microbial numbers on the raw shrimp
and pH in the raw shrimp and cooked meat was observed.
The levels...
The relationship between the decomposition of trimethylamine
oxide in Pacific shrimp and shrimp meat quality was investigated to
evaluate the use of the trimethylamine oxide system as a quality
control indice.
Changes in the levels of trimethylamine oxide and its decomposition
products in whole shrimp stored on ice and in...
The optimum conditions for the proteolytic solubilization of
trash fish and processing carcass waste in a simple shell-in-tube
heat exchange system was investigated. The nutritional and chemical
effects of processing variables were evaluated.
An exogenous source of proteolytic enzymes (albacore tuna
viscera, Thunnus alalunga) yielded a linear increase in the...
The influence of protein adjuncts and variations in pH on the
cook-cool loss, moisture content, and texture of squid gels was
investigated. Break force (P [greater than or equal to] .025), deformation to break (P [greater than or equal to] .01)
and cook-cool loss (P [greater than or equal to]...
Means of improving yield and quality of cooked meat from Dungeness crab (Cancer magister) were investigated. Processing factors of cooking time, cooking medium, and condensed phosphate treatment were evaluated. The effect of condensed phosphate treatment and its interrelationship with cooking time and medium on meat was determined.
Meat yield (wet...
Machine separated flesh from American shad (Alosa
sapidissima) was evaluated for preparing heat set gel products.
Round fish frozen for 15) to 10 months at -18°C served as raw
material for processing investigations. The effectiveness of
various additives and processing procedures for improving gel
strength and sensory characteristics were determined....
Treatment of round shrimp (3 days post-catch) in 6% condensed
phosphate solution at temperatures ranging from 39 (3.9°C) to 86°F
(30°C) reduced meat yield derived by mechanical peeling from 30.0
to 16.4% (wet wt.) according to the linear function y = -.2787 x +
42.7262 (P>.005). Condensed phosphate treatment at...
The effect of the application of condensed phosphate
(Brifisol D-510, commercial mixture of sodium tripolylphosphate
and sodium hexametaphosphate) to round shrimp on the
yield and frozen shelf-life characteristics of cooked meat
was investigated. Condensed phosphate retarded protein solubilization
and increased the water-holding capacity of meat
through steam precooking markedly improving...