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Full-Text Articles in Life Sciences

Freshwater Aquaculture In Western Australia., Fisheries Department Of Western Australia Sep 1990

Freshwater Aquaculture In Western Australia., Fisheries Department Of Western Australia

Fisheries management papers

Freshwater aquaculture in Western Australia is a relatively new industry. The first serious attempts began in 1975 after the Government relaxed the regulations on marron to allow for its farming and sale (at the legal minimum size of 17 mm carapace length). Since 1975, marron have been the focus of most attempts at aquaculture although in recent years trout, yabbies, freshwater aquarium fish and a number of other fish species have received greater attention. In 1984 the Minister for Fisheries established the Fish Farming Legislative Review Committee to review and make recommendations on the fish farming provisions of the Fisheries …


Future Policy For Charter Fishing Operations In Western Australia., P. Millington Sep 1990

Future Policy For Charter Fishing Operations In Western Australia., P. Millington

Fisheries management papers

About 40 boats in Western Australia gain some of their income from taking recreational fishing parties out on charter. Half of these charter boats are also licensed commercial fishing boats. There are few Fisheries Department controls over charter boat fishing at present. However, with increasing tourism and leisure time, there are sound reasons for the Minister for fisheries to tighten up the controls over charter boat fishing to prevent over-exploitation in some areas or on particular stocks.


Phytoplankton In Lake Drummond And Two Drainage Ditches In The Great Dismal Swamp, Virginia, Christine Gregory Phillips Jul 1990

Phytoplankton In Lake Drummond And Two Drainage Ditches In The Great Dismal Swamp, Virginia, Christine Gregory Phillips

Biological Sciences Theses & Dissertations

A twelve month study was conducted on the phytoplankton of Lake Drummond and Washington and Jericho Ditches from December 1988 to November 1989. Surface water samples were collected for nutrient and chlorophyll analysis from June 1989 to November 1989. The dominant phytoplankton component was the pico-nanoplankton (< 3 micron) category. A total of 57 species were identified from Lake Drummond, 51 species from Washington Ditch, and 31 species from the Jericho Ditch. Three major phytoplankton groups were identified at these sites: bacillariophyceans, cyanophyceans and cryptophyceans. The dominant species was the diatom Asterionella formosa. Nutrient and chlorophyll concentrations increased from summer to fall. Based on nutrient and chlorophyll g concentrations and species diversity indices, Lake Drummond is classified as eutrophic.


Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer Jun 1990

Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer

Biology Faculty Publications

The tadpoles of Gastrophryne pictiventris and Nelsonophryne aterrima are described based on material collected in Costa Rica and Panama, respectively. The tadpole of G. pictiventris resembles those of the other species of Gastrophryne. The tadpole of N. aterrima differs from other New World microhylid tadpoles in location of the vent tube (medial), the spiracular opening (ventral to the gut), and eyes (dorsolateral). The unique configuration of mouthparts in N. aterrima is described. Morphological variation in microhylid tadpoles is reviewed and six larval characters are analyzed cladistically for IO New World microhylid genera.


Historic Trends In The Distribution And Populations Of Estuarine Marsh Birds Of The Connecticut River, Robert J. Craig May 1990

Historic Trends In The Distribution And Populations Of Estuarine Marsh Birds Of The Connecticut River, Robert J. Craig

Storrs Agricultural Experiment Station

No abstract provided.


An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy Apr 1990

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …


Reproductive Phenophases And Clutch Characteristics Of Selected Arkansas Amphibians, Stanley E. Trauth, Robert L. Cox Jr., Brian P. Butterfield, David A. Saugey, Walter E. Meshaka Jr. Jan 1990

Reproductive Phenophases And Clutch Characteristics Of Selected Arkansas Amphibians, Stanley E. Trauth, Robert L. Cox Jr., Brian P. Butterfield, David A. Saugey, Walter E. Meshaka Jr.

Journal of the Arkansas Academy of Science

Seasonal reproductive phenomena in 13 species of salamanders and 16 species of anurans from Arkansas were investigated. Most specimens were collected during a span of 6 years (1985-1990). Clutch characteristics, including mensural and meristic data, were determined from gravid females. In some species, the size of egg masses was also documented. Among the plethodontid salamanders, average clutch size (in parentheses) was greatest in Eurycea lucifuga (77.7) and smallest in Plethodon serratus (7.0). One of 2 ambystomatid salamanders (Ambystoma texanum) averaged 545.4 eggs per clutch; the other species (Ambystoma tigrinum) averaged 1 30.5. Siren intermedia nettingi (one of 3 large salamanders …


Genetics Of Interspecific Hybridization In The Triseriatus And Zoosophus Groups Of The Aedes (Protomacleaya) (Diptera: Culicidae)., David B. Taylor Dec 1989

Genetics Of Interspecific Hybridization In The Triseriatus And Zoosophus Groups Of The Aedes (Protomacleaya) (Diptera: Culicidae)., David B. Taylor

David B Taylor

Interspecific hybridization was used to examine the genetics of species divergence and phylogeny of mosquitoes in the Triseriatus and Zoosophus groups of Aedes (Protomacleaya). Aedes zoosophus Dyar & Knab exhibited a relatively high degree of reproductive compatibility with Triseriatus group species. Crosses between A. zoosophus and A. triseriatus (Say) produced fertile female and sterile, intersex, male progeny. Crosses between A. zoosophus females and A. brelandi Zavortink males were sterile with no egg embryonation observed. Crosses between A. zoosophus males and A. brelandi females and reciprocal crosses between A. zoosophus and A. hendersoni (Cockerell) produced sterile, intersex female and male progeny. …