Zusammenfassung: The Desert Fishes Council has moved into the world of electronic publishing on the Internet. Dr. John Rinne (U.S. Forest Service, Flagstaff, Arizona) has allowed the first author to scan his well-known collection of fish photographs into digital format. They have been variously cropped and enhanced, and can now be viewed in different formats or downloaded by anyone in the world with Internet access. The second author is converting the Proceedings (staring with Vol. 24 [1992 meeting]) to hypertext format, so they may be browsed, searched or downloaded. All future DFC Proceedings will be published on WWW at the same time final hard copy is sent to the printer. The World Wide Web (WWW) allows anyone who has obtained free, public domain client software (readily available on Internet), primarily one called Mosaic, to browse effortlessly through multimedia files (graphics, video, sound, formatted text) that are stored on computers around the globe. Multimedia presentations can combine real-time sound, graphics and video with text. Exploration of WWW and the DFC system using Mosaic is facilitated by hypertext links, which offer the simplicity of “point and click” movement through the “cyberspace” of WWW. The Texas Memorial Museum of the University of Texas at Austin is providing storage space for these large DFC files at no charge as a pilot project for other WWW projects at UT, and can likely continue to provide this service for the forseeable future if it receives the usage and growth are predicted. All DFC members are encouraged to provide additional text, graphics and other files for inclusion in the system. Growth of the Internet has been phenomenal, and as more and more people throughout the world obtain access to it, these electronic files will allow DFC to better reach a far larger audience than was formerly possible. DFC members and others using materials provided here will be better equipped to educate the public regarding the plight of desert fishes. The system should also improve communications among ourselves and with others regarding fish conservation efforts throughout the world, and eventually should lead to reduced costs of publishing the Proceedings.

Zusammenfassung: The SPECIESDAB manual describes the use of software created to assist in the retrieval of information relevant to species of interest to fisheries. Data on scientific and vernacular nomenclature, biology, fishing gears, and geographical distribution are included for species that belong to certain marine resource groups. This information is derived from the FAO Fisheries Department species identification and data programme publications and the software is designed to permit continual updating as new publications on other resource groups appear. To date, some 25 major resource groups are covered. Among these are shrimps, lobsters, cephalopods, sharks, marine turtles, and 20 families of bony fishes, which together form a significant component of world fisheries. The program uses a menu system to provide users easy access to the information contained in SPECIESDAB. The manual includes extensive examples of how to use the software. On-line help is also available. Extensive query and reporting capabilities are provided to access data on valid scientific names, synonyms, national and local names, official FAO trilingual names, size, habitat, behaviour, kinds of gear utilized in the fishery, and level of interest to fisheries. Geographical information may be obtained by species, by country, or by fishing area. Data may be extracted for either a single resource group or for all resource groups in combination. Furthermore, the user interested in using only the data of species occurring in a particular geographical area can create, with the Regional option, a sub-database including only the species found in the countries selected. This option can be useful for regional bodies and working groups. SPECIESDAB includes a bibliographic reference system, which may be updated by the user as well as utilities for exporting data.

Zusammenfassung: Standard 0-group indices and distribution maps are now produced based on hand-drawn maps using AutoCad with some additional procedures. This paper briefly describes the method. The paper further describes ways of importing coastlines and survey data directly into standard computer programs such as AutoCad and SAS. Standard methods are used for gridding data, producing isolines and further calculation of abundance indices and presentation of distributions. Interactive editing of distribution maps are made, which makes corresponding automatic updating of indices possible.

Zusammenfassung: Studies of predator-prey interactions have been limited to laboratories or relatively small scale field experiments because of logistic difficulties in large scale field experiments. Much evidence has suggested that predictions based on small scale experiments on predator-prey interactions may not be simply extended to large scales, e.g. whole system. This study was designed to examine predation effects on a prey fish assemblage at the whole lake scale. After a year of premanipulation study, northern pike (Esox lucius) were introduced into a small piscivore-free lake inhabited by 14 species of fishes. In the third and fourth years, the lake was divided by a large mesh fence and northern pike were introduced into one half of the lake. Predation effects on individual prey population were estimated for both direct effects (i.e., consumption of prey species) and indirect effects, including habitat changes associated with predator avoidance behavior, increase of emigration rates and changes of population size structure. The relative importance of direct versus indirect effects was examined using randomized intervention analysis along with a model that quantifies the indirect effects. Decreases of prey fish biomass due to increased emigration was at least as great as that due to the direct effect of consumption when prey biomass was high (>40 kg/ha) but not when prey biomass was low (<30 kg/ha). Significant indirect effects included dramatically decreased abundance of the dominant species (northern redbelly dace, Phoxinus eos), increase of some rare species (sunfish, Lepomis spp. and creek chub, Semotilus atromaculatus), and decreased mean sizes of redbelly dace. Indirect effects occurred rapidly and were most apparent immediately following the introduction of northern pike. Community responses to northern pike predation included changes of species composition, species diversity and community stabilities. The fish communities were significantly different among the pre-pike period, pike period and post-pike period. The greatest variance was related to abundances of redbelly dace and sunfish. However, predation effects on the prey fish community depended on the observational scales used to determine community structure. (DBO)