Review of surrogacy program for endangered victorian brush-tailed rock wallaby (Petrogale penicillata) with special reference to animal husbandry and veterinary considerations.

A surrogacy program to increase the reproductive rate of the critically endangered Victorian brush-tailed rock wallaby (Petrogale penicillata), initially developed in semicaptive conditions, was established in close captivity at Adelaide Zoological Gardens in 1998. Pouch young were removed from their mothers on days 8-20 or 40-45 after parturition and placed onto the teat of a tammar wallaby (Macropus eugenii) or yellow-footed rock wallaby (Petrogale xanthopus xanthopus) surrogate mother. During the early years of the program, mortality of brush-tail pouch young was high (12/16, 75%), both before transfer while still on their mother (5/16) and after transfer to a surrogate mother (7/11). Changing pouch young transfer methodology and improving the health status of the surrogate animals during the later years of the program significantly reduced the mortality of brush-tail pouch young (8/29). Under the new methodology, no mortality of brush-tail pouch young was observed between birth and the time of transfer, (0/29), and after transfer, pouch young mortality rate was eight of 29 (28%). Factors implicated in the improved success of the program included 1) the early transfer (between days 8 and 20) of brush-tail pouch young from mother to surrogate mother, 2) review of the veterinary history and health of the animals selected to act as surrogate mothers, and 3) increased access to grazing pasture for foster mothers. The reproductive rate of the brush-tail females in the later years of the breeding program was sixfold above natural birthing rates. These and other factors important in establishing a breeding program of this nature are discussed.     

Using DNA from museum specimens to preserve the integrity of evolutionarily significant unit boundaries in threatened species

Use of DNA from museum samples is a powerful tool to directly establish historical ESU boundaries in areas where populations of a species have been extirpated. The brush-tailed rock-wallaby (Petrogale penicillata) has suffered extensive reductions in range and population size since European settlement in Australia. Populations of this species have been grouped into three putative evolutionarily significant units (ESUs) which were likely once contiguous along the south-east coast of Australia. However, there is currently a gap of ∼320 km between extant populations of the southern and central ESUs. Conservation plans for the brush-tailed rock-wallaby include re-introductions of animals to locations within their former range. In order to preserve the historic geographic integrity of the genetic lineages within the species, it is necessary to map the boundary between the southern ESU and central ESU to allow more informed management decisions about which lineages should be used to re-stock specific geographic locations. We have extracted DNA from samples from museum specimens that come from locations between the southernmost extant colony of the central ESU and the remaining wild colony of the southern ESU. We sequenced a 177 bp interval of the left domain of the mitochondrial DNA control region and used phylogenetic analysis to group obtained sequences with previously published sequences belonging to the three ESUs. We have extended the range of the central ESU southwards and the range of the southern ESU northwards such that the gap between the ESUs is now approximately 160 km. We recommend that, where suitable historical museum collections exist, this technique be incorporated into re-introduction plans for other threatened species.     

Effects of fungicides used to control Rhynchosporium secalis where benzimidazole resistance is present

The effects of fungicides used to control Rhynchosporium secalis in winter barley were investigated in five field trials in Co. Down, Northern Ireland. Benzimidazole resistance was present in the R. secalis population of each site. Fungicide performance was evaluated in terms of disease control, maintenance of green leaf area, grain yield and grain quality. Samples of R. secalis isolates taken before and after treatment in each field were assessed for sensitivity to carbendazim in the laboratory. Carbendazim contributed little to disease control, the maintenance of green leaf area, grain yield or grain quality. Carbendazim was associated with a significant increase in disease severity in some plots. Treatments containing carbendazim, either alone or in mixture, caused an increase in the proportion of carbendazim-resistant isolates within R. secalis populations. Propiconazole-containing treatments performed well in terms of disease control, maintenance of green leaf area and grain quality. They caused no change in carbendazim resistance frequency.     

Relationships among vertically structured in situ measures of turbulence,larval fish abundance and feeding success and copepods on Western Bank,Scotian Shelf

Using vertically stratified data of the abundance of silver hake (Merluccius bilinearis) larvae and concentrations of copepods collected in the field, we examine relationships among the vertical distribution of larval fish, their potential prey, feeding success and water column turbulence. Water column turbulence and associated stratification parameters were estimated from: (i) in situ measures of turbulent kinetic energy dissipation (?) provided by an EPSONDE profiler; (ii) in situ wind speed; (iii) the Richardson number (Ri); and (iv) the buoyancy frequency (N²). Small (< 5 mm total length) silver hake were more abundant in the least turbulent waters (i.e. at a minimum in the rate of dissipation of turbulent kinetic energy, ? < 10^–7 W kg^?1; Ri > 0.25; N² > 0.001 (rad s^–1)²). Partial correlations amongst ?, N² and small hake larvae were significant only for N². The abundance of larger (> 5 mm total length) hake larvae was positively correlated with depth and was not associated with either ? or N². Vertical distributions of three potential prey (classified by stage) were variable. Early stage copepodids were positively correlated with N² and negatively correlated with ?. We found no evidence of diel distribution patterns for small (< 5 mm total length) hake larvae or for any of the developmental stages of the copepods examined. Neither estimate of water column turbulence inferred from wind speed nor from Ri was meaningfully related to in situ estimates of ? or to larval fish abundance. Feeding success, measured either as prey items (gut)^–1, average prey length, or total prey volume (gut)^–1, was not related to predicted encounter rates between days. However, the average prey length (gut)^–1 was significantly (P < 0.01) related to water column turbulence. These conflicting results suggest that the relationship between larval feeding and the environment is more complicated than assumed. We conclude that without substantial high resolution in situ examination of the relationship between the vertical distributions of turbulence, larvae and their prey, the growing acceptance in the secondary literature that turbulence has a positive and biologically meaningful effect on trophic interactions between fish and their zooplankton prey (a generalization based largely on modelling and laboratory experiments) is premature.     

Nutritional evaluation of tepary bean: Elemental analysis of seed

Tepary bean (Phaseolus acutifolius var. latifolius), a potential arid‐land legume crop, was analyzed for total protein, oil, fiber and mineral content. Results indicate the bean would be adequate in these nutrients for a human diet if deficient amino acids in the seed‐protein were complimented.     

Stable antibody-producing murine hybridomas

A method is described for obtaining antibody-producing hybridomas that are preferentially retained in cultures of fused mouse spleen and myeloma cells. Hybridomas are produced by fusing mouse myeloma cells that are deficient in adenosine phosphoribosyltransferase (APRT) with mouse spleen cells containing Robertsonian 8.12 translocation chromosomes. The cell fusion mixtures are exposed to a culture medium that can be utilized only by APRT-positive cells, which results in the elimination of both unfused APRT-deficient myeloma cells and non-antibody-producing APRT-deficient hybridomas that arise by segregation of the 8.12 translocation chromosomes containing the APRT genes and the active heavy chain immunoglobulin gene.     

An electrophoretically-detectable genetic tag for hatchery-reared brown trout (Salmo trutta L.)

The feasibility of incorporating a unique genetic marker into a hatchery strain of brown trout is investigated. The allele Pgi-3(110) is shown to have a very limited distribution among native trout populations in Great Britain and Ireland yet is present, at low frequency, in all three hatchery stocks examined. The potential therefore exists to breed a strain of hatchery brown trout homozygous for the Pgi-3(110) allele. Individuals of such a strain could be unambiguously distinguished from virtually all native stocks. The usefulness of the genetic tag is enhanced by the strong expression of Pgi-3 in adipose fin, permitting simple biopsying. Data from population surveys and the monitoring of experimental progeny suggest selective equivalence among Pgi-3 genotypes.