Percentage Frequency Of Occurrence Research Articles

Distribution and Use of Shallow‐Water Habitats by Pacific Sand Lances in Southeastern Alaska

AbstractThe Pacific sand lance Ammodytes hexapterus is an important prey species, but little is known about its distribution and habitat use, especially among early life stages in southeastern Alaska. To address this information need, we examined the distribution and habitat use of Pacific sand lances by sampling a variety of shallow‐water habitats (depth < 6 m) with a beach seine seasonally throughout southeastern Alaska from 1998 to 2006. An estimated 81,939 Pacific sand lances were captured at 31 of 49 locations and in 109 of 610 seine hauls. Total catch and percent frequency of occurrence (FO; [number of seine hauls with Pacific sand lances/total number of hauls] × 100) was greatest in summer (73,033 fish, FO = 21%), followed by spring (8,857 fish, 18%) and winter (49 fish, 1%). Pacific sand lances were captured in all habitat types; total catch in spring ranged from 16 fish in understory kelp (e.g., Laminariales) to 8,525 fish in bedrock outcrops, whereas total catch in summer ranged from 5,858 fish in sand to 54,851 fish in eelgrass Zostera marina. The FO was relatively consistent among the above habitat types and ranged from 15% to 20% in spring and from 15% to 35% in summer. Pacific sand lances use a variety of shallow‐water habitats for at least 4 months in spring and summer; habitat is not limited to sandy substrates for burrowing but also includes bedrock, eelgrass, and kelp as likely foraging areas. Age‐1 and younger Pacific sand lances dominated our catches; size range of captured fish was 39‐168 mm fork length. The importance of Pacific sand lances in the diets of other fishes, seabirds, and marine mammals justifies the need to better understand, protect, and manage habitats that are essential to Pacific sand lances.

Dietary Observations on the Asian Softshell Turtle (Amyda cartilaginea) from Sarawak, Malaysian Borneo

ABSTRACT We examined the diet of Amyda cartilaginea from 2 localities in Sarawak: Loagan Bunut National Park and Balai Ringin. The most commonly found items in stomach contents, when using percentage frequency of occurrence, were plant material (77%) and unknown vertebrate parts (55%). Fecal analysis indicated similar results: plant material (100%), unknown vertebrate parts (84%), fish (69%), and unknown arthropods (62%). Results indicate that A. cartilaginea is an opportunistic omnivore.

Evaluation of aquatic macrophyte community response to island construction in the Upper Mississippi River

Impounding large rivers has often led to reductions in aquatic habitat diversity over time. One approach used to restore habitat on the Upper Mississippi River is island construction. A specific purpose of island construction is to increase the growth and diversity of aquatic macrophytes. We addressed whether this purpose was met for islands constructed in a reach of the Upper Mississippi River. Aquatic macrophyte levels and richness around 2 constructed island complexes were compared with those in open water reference areas in 1998 and 2000. These data suggest that macrophyte levels increased in the construction area relative to the reference area for the second but not the first island complex. Findings were similar for both percent frequency of occurrence and richness index models. These differences in response are attributed to the differing maturities of the 2 island complexes. The first complex was completed 6 years prior to the initiation of aquatic macrophyte sampling, whereas sampling began midway through the construction phase of the second complex. The response of aquatic macrophytes in the first island complex may have stabilized prior to sampling, whereas aquatic macrophyte responses to construction of the second island complex were partially captured during the sampling period. These findings suggest that island construction positively influences aquatic macrophyte levels in impounded reaches of large rivers.

Computed Tomography Coronary Angiography for Rapid Disposition of Low‐risk Emergency Department Patients with Chest Pain Syndromes

Patients with recent normal cardiac catheterization are at low risk for complications of ischemic chest pain. Computed tomography (CT) coronary angiography has high correlation with cardiac catheterization for detection of coronary stenosis. Therefore, the investigators' emergency department (ED) incorporated CT coronary angiography into the evaluation of low-risk patients with chest pain. To report on the 30-day cardiovascular event rates of the first 54 patients evaluated by this strategy. Low-risk chest pain patients (Thrombolysis In Myocardial Infarction [TIMI] score of 2 or less) without acute ischemia on an electrocardiogram had CT coronary angiography performed in the ED. If the CT coronary angiography was negative, the patient was discharged home. The main outcomes were death and myocardial infarction within 30 days of ED discharge, as determined by telephone follow up and record review. Data are presented as percentage frequency of occurrence with 95% confidence intervals (CIs). Of the 54 patients evaluated, after CT coronary angiography, 46 patients (85%) were immediately released from the ED, and none had cardiovascular complications within 30 days. Eight patients were admitted after CT coronary angiography: one had >70% stenosis, five patients had 50%-69% stenosis, and two had 0-49% stenosis. Three patients had further noninvasive testing; one had reversible ischemia, and catheterization confirmed the results of CT coronary angiography. All patients were followed for 30 days, and none (0; 95% CI = 0 to 6.6%) had an adverse event during index hospitalization or at 30-day follow up. When used in the clinical setting for the evaluation of ED patients with low-risk chest pain, CT coronary angiography may safely allow rapid discharge of patients with negative studies. Further study to conclusively determine the safety and cost effectiveness of this approach is warranted.

Diets of Free-Ranging Mexican Gray Wolves in Arizona and New Mexico

Systematic diet studies of Mexican gray wolves (Canis lupus baileyi) were not conducted before wolves were extirpated by the late 1960s from the southwestern United States. We collected carnivore scats (n = 1,682) from the Apache and Gila national forests in Arizona and New Mexico, USA, from April 1998 through October 2001 and identified scats to species using traditional field methods, of which 251 were identified as Mexican wolf scats. We found the diet consisted of large-sized food items (92.8% percent frequency of occurrence [PFO]), primarily elk (Cervus elaphus) adults (36.6% PFO) and calves (36.2% PFO). Biomass calculations indicated that Mexican wolves consumed 414 kg of prey as represented by the scats, with elk representing 76.7% of the biomass. When comparing PFO with percent biomass, PFO calculations may have underrepresented larger food items and percent biomass may have overrepresented smaller food items. We compared the diet composition of Mexican wolf scats (n = 251) to the diets reported in previous North American gray wolf (C. lupus) studies (n = 7). The high proportion of elk in Mexican wolf diets in our study area may reflect the low-density, early colonizing stage of the wolf population and elk probably being the most numerous ungulate in our study area. Our results suggested that free-ranging Mexican wolves consumed a higher proportion of large-sized prey than other North American gray wolves. Our results provide baseline diet information for a newly reestablished wolf population.

Size, Length-Weight Relationships, Reproduction And Trophic Biology Of Chrysichthys nigrodigitatus And Chrysichthys auratus (Siluriformes: Bagridae) In A Natural West African Lake

Size, length-weight relationships, reproduction and trophic biology of Chrysichthys auratus and C. nigrodigitatus were investigated from May, 1990 to July, 1991 as part of the bio-limnological study programme of Agulu lake. C. auratus was more abundant and significantly longer (SL) than C. nigrodigitatus . As an assemblage, the population of Chrysichthys species exhibited isometric length-weight relationship (LWR) (b = 3.109±0.281) thus obeying the ‘cube' law. Fecundity ranged between 625 and 2184 oocytes (mean 1163±461 oocytes) in C. auratus and between 733 and 1988 oocytes (mean 1261±384 oocytes) in C. nigrodigitatus . Mean exponent ( b = 1.765±0.382) of the length-fecundity relationship (LFR) is less than 3 indicating that the Chrysichthys species exhibit substantial fish size - egg size changes. The mean weight exponent ( b = 0.56±0.23) of the weight-fecundity relationship (WFR) is significantly different from 1 showing that fecundity does not relate linearly with weight. Standard length (SL) is the best predictor of fecundity in C. auratus while in C. nigrodigitatus it is body weight (B w ). Breeding in C. auratus occurred between April and September. The diameter of ripe oocytes was 2.04 ± 0.32 mm in C. auratus and 2.1±0.36 mm in C. nigrodigitatus . The species fed on both plant and animal materials with the animal component dominating [56.8% and 62.1% percentage frequency of occurrence (%FO); 53.6% and 42.6% volumetric index (VI) for C. auratus and C. nigrodigitatus respectively]. The high Spearman's rank coefficient (r = 0.75) and the Raabe's factor (R = 59.0%, %FO; 56.8%, VI) show strong similarity and overlap in the food types of the two species. Similarly, Raabe's factor (R = 62.7%) indicates trophic niche overlap between the small- [8 - 14 cm standard length (SL)] and large-sized (> 15 cm SL) individuals of C. auratus . Key Words: Size, morphometric relationships, reproduction, food, Chrysichthys species Bio-Research Vol.2(1) 2004: 47-58

Distribution, Density, Diet and Habitat Use of the Otter in Relation to Land Use in the Araglin Valley, Southern Ireland

The distribution, density, diet and habitat use of the otter (Lutra lutra) were examined in the Araglin Valley, in counties Cork, Tipperary and Waterford. Otter signs (tracks, spraints, anal secretions, holts, etc.) and environmental conditions (river depth, river width, flow regime, vegetation cover, etc.) were recorded at 112 sites across three habitat types (agriculture, moorland and forestry) in the river valley. Three definite home range boundaries were delineated by high levels of sprainting and scraping, and results indicated the presence of six or seven otters. Significant correlations were recorded between otter signs and river depth, river width, lying-up availability and presence of holts, but no trends were found between otter signs and vegetation cover or flow velocity. A positive relationship was recorded between spraints and vegetation cover in the agriculture and moorland habitats, but a negative correlation was found in the forested sites. Percentage frequency of occurrence, relative percentage of frequency, and percentage bulk (Sc%) were calculated for twelve food categories based on seasonal data sets. Fish (mainly salmonids and eels) were the predominant food category in each season (Sc% = 70.03). Other significant food categories included small quantities of mammals, birds, frogs and crayfish (both in February and March). Considerable variation in otter diet was revealed and was related to differences among three different habitat types and to the location of the home range. In home range 3, fish prey were relatively scarce, while birds and frogs were more important. In contrast, fish was the more important food in home ranges 1 and 2. The trophic niche breadth of otter, evaluated using Levin's index, varied little throughout the study period, with a peak in spring/early summer and a minimum value in late autumn (October-November).

Microbiological Assay Of Ingredients, Contact Surfaces And Stages In <i>Akara</i> Processing At Three Locations In Maiduguri, Nigeria

Sample at various stages and contact surfaces were obtained during akara processing from three locations in Maiduguri metropolis. The locations were Hausari, Mairi and Wulari. Samples of the ingredients and swabs of contact surfaces were taken. Total aerobic plate count, coliform count, taphylococcal count and yeast/mould count, were determined. Microorganism were solated, identified and their percentage frequency of occurrence on plated samples of the ingredients and contact surfaces were also determined. The total aerobic mesophilic count of ingredients from the three locations range from 3.10 to 8.40 cfu/g, while coliform count ranged from 1.10 to 9.00 cfu/g, staphylococcal count ranged from 1.20 to 3.29 cfu/g and yeast/mould count ranged from 1.60 to 4.80 cfu/g. The total aerobic plate count of contact surfaces ranged from 4.20 to 7.90 cfu/cm2, coliform from 1.00 to 7.80 cfu/cm2, staphylococcal count from 2.10 to 5.90 cfu/cm2 and yeast/mould count from 1.20 to 4.80 cfu/cm2. The predominant microorganisms isolated from this study were Klebsiella pneumoniae, Bacillus subtilis, candida tropicalis and Aspergillus niger. They occurred at all the various stages and on contact surfaces during akara processing at percentage frequency of occurrence ranging from 5 to 50%. The presence of Staphylococcus aureus, Escherichia coli, Streptococcus feacalis and klebsiella pneumoniae is not a healthy development. These microorganisms are pathogenic and therefore their presence during akara processing could cause a serious health problem. The need for advising akara producers and vendors of the necessity to adopt strict hygienic practice, at various stages of processing is essential. Agro-Science Vol.2(1) 2001: 42-49

Exposure potential of other common Penicillium species in indoor environments

Rationale Penicillium, a fungal genus with about 600 described species, is considered an important allergen source. However, only 4 species, P. brevicompactum, P. chrysogenum, P. citrinum, and P. oxalicum have been characterized for allergen content. We examined the frequency of individual Penicillium species in environmental samples to determine the relevance of currently available allergens. Methods A total of 1768 culturable air and 1547 surface culture samples were examined from homes and adjacent outdoor environments throughout the United States. All Penicillium species were identified using Pitt's morphologically based taxonomy. Percent frequency of occurrence was calculated for 24 Penicillium species. Results Within culturable air samples, the most frequent Penicillium species were P. brevicompactum with 26%, P. chrysogenum and P. citrinum with 17%, P. purpurogenum with 10%, and P. glabrum with 9%. Within surface cultures, predominant species were, P. chrysogenum and P. citrinum with frequencies of 14.5% each followed by P. brevicompactum and P. aurantiogriseum with 7% and 6% frequency, respectively. The frequency of P. oxalicum was among the lowest with 1.4%. Conclusions The allergens of the three most prevalent Penicillium species have been studied. However, other common species have not been analyzed. Future allergen studies should focus on P. purpurogenum, P. glabrum, and P. aurantiogriseum. This database is also being studied for the relative prevalence of species belonging to the genus Aspergillus.

Distribution, Density, Diet and Habitat Use of the Otter in Relation to Land Use in the Araglin Valley, Southern Ireland

The distribution, density, diet and habitat use of the otter (Lutra lutra) were examined in the Araglin Valley, in counties Cork, Tipperary and Waterford. Otter signs (tracks, spraints, anal secretions, holts, etc.) and environmental conditions (river depth, river width, flow regime, vegetation cover, etc.) were recorded at 112 sites across three habitat types (agriculture, moorland and forestry) in the river valley. Three definite home range boundaries were delineated by high levels of sprainting and scraping, and results indicated the presence of six or seven otters. Significant correlations were recorded between otter signs and river depth, river width, lying-up availability and presence of holts, but no trends were found between otter signs and vegetation cover or flow velocity. A positive relationship was recorded between spraints and vegetation cover in the agriculture and moorland habitats, but a negative correlation was found in the forested sites. Percentage frequency of occurrence, relative percentage of frequency, and percentage bulk (Sc%) were calculated for twelve food categories based on seasonal data sets. Fish (mainly salmonids and eels) were the predominant food category in each season (Sc% = 70.03). Other significant food categories included small quantities of mammals, birds, frogs and crayfish (both in February and March). Considerable variation in otter diet was revealed and was related to differences among three different habitat types and to the location of the home range. In home range 3, fish prey were relatively scarce, while birds and frogs were more important. In contrast, fish was the more important food in home ranges 1 and 2. The trophic niche breadth of otter, evaluated using Levin's index, varied little throughout the study period, with a peak in spring/early summer and a minimum value in late autumn (October-November). Paola Ottino and Paul Giller (corresponding

Distribution, Density, Diet and Habitat Use of the Otter in Relation to Land Use in the Araglin Valley, Southern Ireland

The distribution, density, diet and habitat use of the otter (Lutra lutra) were examined in the Araglin Valley, in counties Cork, Tipperary and Waterford. Otter signs (tracks, spraints, anal secretions, holts, etc.) and environmental conditions (river depth, river width, flow regime, vegetation cover, etc.) were recorded at 112 sites across three habitat types (agriculture, moorland and forestry) in the river valley. Three definite home range boundaries were delineated by high levels of sprainting and scraping, and results indicated the presence of six or seven otters. Significant correlations were recorded between otter signs and river depth, river width, lying-up availability and presence of holts, but no trends were found between otter signs and vegetation cover or flow velocity. A positive relationship was recorded between spraints and vegetation cover in the agriculture and moorland habitats, but a negative correlation was found in the forested sites. Percentage frequency of occurrence, relative percentage of frequency, and percentage bulk (Sc%) were calculated for twelve food categories based on seasonal data sets. Fish (mainly salmonids and eels) were the predominant food category in each season (Sc% = 70.03). Other significant food categories included small quantities of mammals, birds, frogs and crayfish (both in February and March). Considerable variation in otter diet was revealed and was related to differences among three different habitat types and to the location of the home range. In home range 3, fish prey were relatively scarce, while birds and frogs were more important. In contrast, fish was the more important food in home ranges 1 and 2. The trophic niche breadth of otter, evaluated using Levin's index, varied little throughout the study period, with a peak in spring/early summer and a minimum value in late autumn (October-November).

Diet of mammalian predators in braided river beds in the central South Island, New Zealand

In New Zealand, five of the six endemic bird species that breed primarily in South Island braided river beds are classed as threatened. A major cause of decline for these species is predation by introduced mammals, and predator-trapping programs are undertaken in the braided rivers of the Mackenzie Basin to protect them. Trapping programs carried out between September 1997 and April 2001 provided the opportunity to investigate predator diet from the gut contents of 375 cats (Felis catus), 371 ferrets (Mustela furo) and 86 stoats (Mustela erminea). As a percentage frequency of occurrence of the main prey items, cat diet consisted of lagomorphs (present in 70% of guts), birds (in 47%), lizards (30%) and invertebrates (36%). Ferret diet consisted of lagomorphs (69%) and birds (28%). Stoat diet consisted of lagomorphs (50%), birds (51%), lizards (21%) and invertebrates (23%). The frequency of occurrence of birds in all three predators was higher in the spring/summer of 1997 – immediately after rabbit haemorrhagic disease (RHD) was introduced – than in any other previous diet study on these braided rivers. This suggests that RHD did lead to increased predation pressure on birds, at least in the short term.

Incomplete data reporting in studies of emergency department patients with potential acute coronary syndromes using troponins.

A multidisciplinary panel of experts is developing standardized reporting criteria for risk stratification studies of emergency department (ED) patients with potential acute coronary syndromes (ACS). The authors assessed the need for such criteria by reviewing published studies to determine whether these core criteria currently are being reported. Studies published during 2000-2001 in eight journals representing emergency medicine, cardiology, and general medicine that evaluated the cardiac troponins for risk stratification of ED patients with chest pain were identified by a systematic MEDLINE review. Two raters independently analyzed each study with a structured tool. The presence or absence of 47 core criteria in eight major reporting categories, which were determined by expert consensus, was abstracted from the articles. When the two raters disagreed, discrepancies were resolved by consensus. Data are presented as percent frequency of occurrence with 95% confidence intervals. Twenty-two articles met inclusion criteria. The two reviewers had a median of 7.5 initial discrepancies per article (interquartile range = 6 to 10) but achieved consensus on all. The median of the percent of articles reporting the core criteria within each major reporting category is shown [table: see text]. Many of the 47 items considered core criteria by the expert committee writing standardized reporting guidelines for risk stratification studies of potential ACS patients were not reported often in major cardiology and emergency medicine journals. There seems to be a need for standardized reporting guidelines because important information is not currently being reported.

Incomplete Data Reporting in Studies of Emergency Department Patients with Potential Acute Coronary Syndromes Using Troponins

Abstract Objectives: A multidisciplinary panel of experts is developing standardized reporting criteria for risk stratification studies of emergency department (ED) patients with potential acute coronary syndromes (ACS). The authors assessed the need for such criteria by reviewing published studies to determine whether these core criteria currently are being reported. Methods: Studies published during 2000–2001 in eight journals representing emergency medicine, cardiology, and general medicine that evaluated the cardiac troponins for risk stratification of ED patients with chest pain were identified by a systematic MEDLINE review. Two raters independently analyzed each study with a structured tool. The presence or absence of 47 core criteria in eight major reporting categories, which were determined by expert consensus, was abstracted from the articles. When the two raters disagreed, discrepancies were resolved by consensus. Data are presented as percent frequency of occurrence with 95% confidence intervals. Results: Twenty‐two articles met inclusion criteria. The two reviewers had a median of 7.5 initial discrepancies per article (interquartile range = 6 to 10) but achieved consensus on all.Conclusions: Many of the 47 items considered core criteria by the expert committee writing standardized reporting guidelines for risk stratification studies of potential ACS patients were not reported often in major cardiology and emergency medicine journals. There seems to be a need for standardized reporting guidelines because important information is not currently being reported.

Feeding ecology of the three juvenile phases of the spiny lobster Panulirus argus in a tropical reef lagoon

The three juvenile phases of the spiny lobster Panulirus argus (algal phase: 5–15 mm carapace length, CL; postalgal phase: 15–45 mm CL, and subadults: 45–80 mm CL) occur in the reef lagoon at Puerto Morelos, Mexico. The algal phase abounds in this lagoon, which is covered by extensive seagrass–algal meadows, but the density of postalgal and subadult juveniles is low, owing to the scarcity of crevice-type shelters suitable for these phases. The feeding ecology of the three juvenile phases was investigated to examine whether spatial or temporal differences in food intake, diet composition, or nutritional condition occurred among phases and could partially account for the low abundance of the larger juveniles. Juveniles were collected by divers at night, from January to November 1995, throughout the mid-lagoon and back-reef zones. Percent stomach fullness, relative weight of the digestive gland (RWDG, an index of nutritional condition), percent frequency of occurrence and percent volume of food categories in the diet were compared between sexes, juvenile phases, molt stages (postmolt, intermolt, premolt), seasons, and sampling zones (mid-lagoon and back-reef zones). Significant differences in stomach fullness occurred only among molt stages, mainly because postmolt individuals had emptier stomachs. The main food categories in all juvenile phases were crustaceans (mostly hermit crabs and brachyurans) and gastropods, but the food spectrum was wide, including many other animal taxa as well as plant matter. In June 1995, the epibenthic macrofauna was sampled in five sites in the lagoon that differed in their amount of vegetation. The most abundant taxa in all sites were decapods and gastropods, but density and diversity measures showed that the distribution of these potential prey taxa for juvenile P. argus was rather patchy. Diet overlap in juvenile lobsters was high between sexes, juvenile phases, sampling zones, seasons, and molting stages, indicating that all juveniles fed on the same general food categories throughout time. The only factor that affected the RWDG was the juvenile phase. RWDG was significantly lower in subadults than in algal and postalgal phases, suggesting a poorer nutritional condition in the largest juveniles. This may be related to the scarcity of suitable shelters for large juveniles throughout the lagoon, which may preclude subadults from exploiting food resources in areas of the lagoon where shelter is limited.

Coyote diets in the Chihuahuan Desert, more evidence for optimal foraging

With 7 years data on coyote prey use and availability, we tested three predictions based on optimal foraging: (1) the proportion eaten of the most profitable item is constant regardless of availability, (2) under a constant density of higher ranked prey, there is no relationship between the proportion eaten of low profitability items and their density, (3) the ratio of number consumed to availability for the highest ranking prey item should be negatively related to availability. We tested these predictions with regression analyses. We found no significant linear relationship between lagomorph availability and use. There was no significant linear relationship between percent frequency of occurrence of rodents nor arthropods and their respective availabilities for two levels of availability of lagomorphs. We found a significant negative relationship between number consumed/number available to availability for lagomorphs but not for rodents nor arthropods. The results supported the three predictions and we concluded that coyotes are foraging optimally.

A Caloric-based Evaluation of Diet Indices for Largemouth Bass

Selection of methods for quantitative description and assessment of food habits is a concern for trophic investigations. We used diet data for largemouth bass Micropterus salmoides, to compare a caloric-based approach with eight diet indices: percent frequency of occurrence, percent total number, percent total weight, mean relative number, mean relative volume, relative importance index, prey-importance index, and mean stomach fullness. Mean caloric contribution of stomach contents for each prey taxon was used as a standard to compare diet indices. Temporal differences in composition and caloric contents of largemouth bass stomach contents were apparent. Most diet indices provided similar assessments when diets were dominated by a single prey type (i.e., gizzard shad during June-October). However, diet indices evaluated provided dissimilar assessments of stomach contents when a variety of prey with differing caloric densities were consumed (e.g., April). Mean stomach fullness and percent by volume were significantly (p < 0.002) correlated (r = 0.94 − 1.00) with mean caloric contribution of largemouth bass stomach contents during all months. Unlike percent by weight, mean stomach fullness accounted for differences in fish size and stomach capacity. Thus, mean stomach fullness by prey type appears to be the most appropriate index when objectives include simplified caloric-based assessments of fish diets.

The diet of stoats (Mustela erminea) and weasels (Mustela nivalis) in Great Britain

AbstractThe diet of 789 stoats Mustela erminea and 458 weasels M. nivalis collected in Great Britain between 1995 and 1997 is described from analyses of their gut contents. As a percentage frequency of occurrence, stoat diet consisted of 65% lagomorphs, 16% small rodents and 17% birds and birds' eggs. Weasel diet consisted of 25% lagomorphs, 68% small rodents, mainly Microtus agrestis, and 5% birds and birds' eggs. Male stoats ate a greater proportion of lagomorphs than females, which ate more small rodents. No differences in diet between the sexes of the weasels were detected. The proportion of lagomorphs in the diet of both species was greatest in the spring. Both species ate more lagomorphs in the 1990s than in the 1960s as a result of increasing rabbit populations following recovery from myxomatosis. The importance of small rodents had decreased for stoats and increased for weasels. Both species had a dietary niche that was more specialized than in the 1960s. The implications of these findings for stoat and weasel conservation are discussed.

Diet of the mulgara, Dasycercus cristicauda (Marsupialia : Dasyuridae), in the Simpson Desert, central Australia

The diet of the mulgara, Dasycercus cristicauda, from the Simpson Desert in Queensland, was analysed using scats collected between 1990 and 1995. Insects, arachnids and rodents were the main classes of prey of D. cristicauda, but reptiles, centipedes and small marsupials were also consumed. Insects represented 92% by percentage frequency of occurrence in scats, while rodents represented 33% by percentage frequency. Invertebrate prey ≥6 mm in length and vertebrate prey occurred frequently in scats, but small prey ( 1–5 mm), when present, occurred in large numbers. D. cristicauda ate more individual prey items in spring and winter than in autumn, and more large-sized prey in spring than in autumn. In autumn, D. cristicauda consumed mostly insects (100% by frequency) and few rodents (8%), but in winter and spring, switched to rodents (38% and 47% respectively) and insects (88% and 93% respectively). Seasonal shifts in diet may reflect changes in the availability of different groups of prey, or changes in prey selectivity by D. cristicauda in response to costs imposed by seasonal reproduction. The dietary flexibility of D. cristicauda may allow individuals to occupy stable ranges, and has perhaps also promoted the persistence of the species in arid areas that have been subjected to changes in land use since European settlement.

The diet of Ophiosparte gigas (Echinodermata: Ophiuroidea) along the Antarctic Peninsula, with comments on its taxonomic status

Analyses of stomach contents of 121 adult Ophiosparte gigas Koehler 1922, collected along the western coast of the Antarctic Peninsula in 1981–1983, show that this species is an active predator and scavenger whose diet consists of representatives of at least 10 phyla. The top five prey groups are sponges, ophiuroids, bivalves, polychaetes and crustaceans by percentage frequency of occurrence, and ophiuroids, bivalves, polychaetes, amphipods and sponges by fullness relative volume. Rankings of prey by various frequency and volume measures vary among different sites suggesting that Ophiosparte gigas is an opportunistic feeder. Significant differences in diet, feeding behavior and morphological characteristics related to feeding, and others, including composition of the integument and structure of the oral and dental plates, show the conventional placement of the monotypic genus Ophiosparte in the Ophiacanthidae is not justified. We suggest placement in the Ophiomyxidae but formal designation within a subfamily must await a thorough revision of the suborder Ophiomyxina.