The extent of stress and eventual mortality in Pacific halibut Hippoglossus stenolepis that resulted from simulated capture by hooking or towing in a net, followed by abrupt exposure to warmer seawater temperature and air, were determined under laboratory conditions. Abrupt exposure to 16degreesC seawater and air after either method of...
The mortality of discarded bycatch is a critical problem in the management of fisheries worldwide. Little is known about the key principles involved in the mortality of discarded bycatch. These principles are best elaborated under controlled conditions in the laboratory where the actions and interactions of stressors found in fishing...
This report summarizes project progress in FY 1974. Activities were directed entirely at completing the fourth and final phase of work started in 1971, i.e., to survey groundfish resources on the continental shelf off Oregon between the Columbia River and Cape Blanco. Objectives of the survey were to obtain estimates...
In a recent note, Collier and Lockwood (1974) compared measurements of total solar radiation on cloudless days at an inland site in England with radiation calculated from empirical expressions derived from (i) data from weather ships in the eastern Atlantic (Lumb 1964) and (ii) measurements of radiation and turbidity in...
The irradiance of the solar beam was measured on cloudless days at Sutton Bonington in the English Midlands and at sites in north-west Scotland. Total and diffuse fluxes were also measured on some days. An attenuation coefficient for aerosol Ta was defined by S(Ta) = S(o) exp ( - Tam)...
Throughout the Applegate watershed, dense, overstocked, immature stands of mixed
conifers and hardwoods and declining stands of mature conifers present significant
and complex silvicultural problems. Stand stagnation is common, as is loss of largediameter
conifers from insects and wildfire. Treatments designed to maintain or
encourage development of large-diameter conifers have...
Surface disinfection of fertilized fish eggs is widely used in aquaculture to reduce
extraovum pathogens that may be released from brood fish during spawning, and this is routinely
used in zebrafish (Danio rerio) research laboratories. Most laboratories use approximately 25-50 ppm unbuffered chlorine solution for 5-10 min. Treatment of embryos...
Direct transmission from parents to offspring, referred to as vertical transmission, occurs within essentially all major groups of pathogens. Several microsporidia (Phylum Microsporidia) that infect arthropods employ this mode of transmission, and various lines of evidence have suggested this might occur with certain fish microsporidia. The microsporidium, Pseudoloma neurophilia, is...
Pseudoloma neurophilia (Microsporidia) is the most common pathogen detected in zebrafish (Danio rerio) from research facilities. The parasite infects the central nervous system and muscle, and may be associated with emaciation and skeletal deformities. However, many fish exhibit subclinical infections. Another microsporidium, Pleistophora hyphessobryconis, has recently been detected in a...
The annual assessment of shrimp fishing performance is important to three interrelated audiences: the regulatory community which defines the policy arena in which fishermen operate, financial institutions which extend credit, and producers. Historic, economic performance data enables policy makers to estimate the ability of producers to absorb production losses and/or...