Status of the Pacific Mackerel resource during 1997 and management recommendations for the fishery

Based on a California Department of Fish and Game (CDFG) projected biomass estimate of 91,200 metric tons for July 1, 1997, the recommended commercial fishery quota for the 1997/98 fishing season is 22,000 metric tons. Age-specific abundance for 1996 was estimated using output from a stock assessment model called ADEPT and certain assumptions about growth and fishing mortality during the first half of 1997. In this year's assessment, abundance estimates made by ADEPT were expanded back in time to cover the 68-year period of 1929 through 1996. The commercial fishery quota recommendation is based upon the prescribed harvest formula for Pacific mackerel that is specified in the California Fish and Game Code. Several sources of information are available for the Pacific mackerel stock, all of which suggest a smaller biomass than was present in the 1980's. Landings from both California and Ensenada, Mexico have sharply decreased and catch rates from the southern California Commercial Passenger Fishing Vessel (CPFV) fleet have declined. Fishery-independent indices of abundance from aerial spotter observations and California Cooperative Oceanic Fisheries Investigations (CalCOFI) ichthyoplankton surveys show similar trends. The 1997 biomass estimate is higher than last year's estimate of 47,160 metric tons because data added to the model this year increased abundance for fish of 1994 and older year classes (age 2+). This year's results indicate there were more fish in the older year classes than estimated in previous assessments. (27pp.

AN ECONOMIC EVALUATION OF LOW INVESTMENT SWINE PRODUCTION SYSTEMS

This publication summarizes an evaluation of smaller and lower investment swine production systems. The systems analyzed range from pasture operations with production during the warmer months to rather intense year-round use of remodeled buildings. In each case the system emphasizes use of facilities that can be constructed and remodeled by the farm operator. The report includes one section for each type of hog production: feeder pig production, farrow-to-finish operations and hog finishing.Livestock Production/Industries,

Stock assessment and management recommendations for Pacific sardine (Sardinops sagax) in 1997

The primary goal of sardine management as directed by the California Fish and Game Code is rehabilitation of the resource with an added objective of maximizing sustained harvest. Accordingly, the Code states that the annual sardine quota can be set at an amount greater than 1,000 tons, providing that the level of take allows for continued increase in the spawning population. We estimated the sardine population size to have been 464,000 short tons on July 1, 1997. Our estimate was based on output from a modified version of the integrated stock assessment model called CANSAR (Deriso et al. 1996). CANSAR is a forward-casting, age-structured analysis using fishery-dependent and fishery-independent data to obtain annual estimates of sardine abundance, year-class strength and age-specific fishing mortality for 1983 through the first semester of 1997. Non-linear least-squares criteria are used to find the best fit between model estimates and input data. Questions about stock structure and range extent remain major sources of uncertainty in assessing current sardine population biomass. Recent survey results and anecdotal evidence suggest increased sardine abundance in the Pacific Northwest and areas offshore from central and southern California. It is difficult to determine if those fish were part of the stock available to the California fishery. In an attempt to address this problem, the original CANSAR model was reconfigured into a Two-Area Migration Model (CANSAR-TAM) which accounted for sardine lost to the areas of the fishery and abundance surveys due to population expansion and net emigration. While the model includes guesses and major assumptions about net emigration and recruitment, it provides an estimate which is likely closer to biological reality than past assessments. The original CANSAR model was also used and estimates are provided for comparison. Based on the 1997 estimate of total biomass and the harvest formula used last year, we recommend a 1998 sardine harvest quota of 48,000 tons for the California fishery. The 1998 quota is a decrease of 11% from the final 1997 sardine harvest quota for California of 54,000 tons. (55pp.

Heat exchangers for animal shelters

1 online resource (PDF, 4 pages)This archival publication may not reflect current scientific knowledge or recommendations. Current information available from the University of Minnesota Extension: https://www.extension.umn.edu

Status of the Pacific mackerel resource and fishery in 1998

Based on the projected Pacific mackerel biomass estimate of 132,500 tons for July 1, 1998, the commercial fishery quota for the 1998/99 fishing season was recommended and set at 33,700 short tons. The 1998 biomass was estimated using output from a stock assessment computer model called ADEPT and certain assumptions about fishing mortality during the first half of 1998. Several important changes were made to improve our assessment during 1998. The assessment model was changed from a quarterly to an annual one and now covers sixty-nine years of fishery data. New indices of relative abundance were added to the analysis to account for changes in mackerel biomass off central and northern California. The July 1, 1998, biomass estimate is slightly higher than last year's CDFG estimate of 101,000 tons for 1997. This year's results indicate there were more fish in the older year classes than previously estimated. (62pp.

Defining the Newborn Piglet’s Thermal Environment with an Effective Environmental Temperature

An effective environmental temperature (EET) developed for newborn piglets describes the thermal environment by incorporating the mean radiant temperature, dry-bulb temperature, and air velocity near the newborn. The adequacy of the defined EET was analyzed by comparing with three published studies on newborn sensible heat loss. Results from the published studies indicate that the EET predicted between 87% and 98% of the variability in the data

Using Covers to Minimize Odor and Gas Emissions from Manure Storages

Odor emissions from animal production sites are typically the leading cause of nuisance complaints. Locating facilities far from neighbors is often a solution to the odor problem, but this is not always an option for producers. Most often, reducing odor emissions from the farm is the only option available