ACCOUNTING FOR FOOD REQUIREMENTS OF SEABIRDS IN FISHERIES MANAGEMENT – THE CASE OF THE SOUTH AFRICAN PURSE-SEINE FISHERY

In South Africa, four of the seabirds that feed mainly on sardine Sardinops sagax and anchovy Engraulis encrasicolus have an unfavourable conservation status or a small population: African penguin Spheniscus demersus, Cape gannet Morus capensis, Cape cormorant Phalacrocorax capensis and swift tern Sterna bergii. Availability of prey is thought to influence their population size, but their food requirements have not been accounted for in management of the purse-seine fishery on sardine and anchovy. Means of identifying and attaining target populations of predators that are dependent on forage fish prey are discussed. Criteria used by The World Conservation Union to assess the conservation status of a species may prove useful in determining minimum viable populations, and the use of functional relationships in coupled models of predators and their prey may allow quantification of levels of escapement of prey that are necessary to maintain or rebuild populations of predators

CONSERVING SURFACE-NESTING SEABIRDS AT THE PRINCE EDWARD ISLANDS: THE ROLES OF RESEARCH, MONITORING AND LEGISLATION

South Africa's subantarctic Prince Edward Islands support substantial proportions of the global populations of a number of surface-nesting seabirds. Populations of most of these have decreased at the islands since the 1980s and 12 of 16 species are regarded as Threatened or Near Threatened regionally or internationally. The main causes of population decreases are thought to be by-catch mortality of albatrosses and giant petrels in longline fisheries, and environmental change influencing availability of prey to penguins and the Crozet shag Phalacrocorax [atriceps] melanogenis. It is proposed that the Prince Edward Islands Special Nature Reserve be expanded to include surrounding territorial waters so as to afford additional protection for seabirds breeding there, especially those species feeding near to the islands. Consideration needs also to be given to listing species as threatened or protected in terms of planned new legislation in South Africa and then developing management plans for them, preferably linked closely with the Agreement on the Conservation of Albatrosses and Petrels and the National Plan of Action (NPOA) – Seabirds. The islands should also be nominated as a Ramsar Wetland of International Importance in recognition of their importance to seabirds, with 13 of the 16 species exceeding the 1&#37 of the global population criterion. A combination of research, monitoring and legislation will help conserve the surface-nesting seabirds of the Prince Edward Islands into the 21st century, but only providing the effects of climate change can somehow be addressed.Afr. J. mar. Sci. 25: 415–42

POPULATION OF THE MACARONI PENGUIN EUDYPTES CHRYSOLOPHUS AT MARION ISLAND, 1994/95–2002/03, WITH INFORMATION ON BREEDING AND DIET

There is indication that numbers of macaroni penguins Eudyptes chrysolophus at subantarctic Marion Island have decreased since the early 1980s. Estimates of the population at the island fell from about 405 000 pairs in 1983/84 and 434 000 pairs in 1994/95 to about 356 000 pairs in 2002/03. Two large colonies, at Bullard Beach and Kildalkey Bay, account for about 85&#37 of the overall population. At both these colonies, the area occupied by breeders showed no trend between 1983/84 and 2002/03, but the mean density of nests decreased. However, error on estimates of abundance at these colonies precludes demonstration of a significant decrease in the overall population. Numbers of occupied nests at other colonies decreased from 79 000 in 1994/95 to 31 000 in 2002/03. At three small colonies there was a significant decrease of 88&#37 between 1982/83 and 2002/03. At Marion Island, macaroni penguins usually breed for the first time when aged about three years. From 1994/95 to 2002/03, pairs fledged an average of 0.46 chicks per year, a number considered insufficient to maintain the population. However, during that period there was a significant increase in reproductive success with time. In the same period, the masses of males and females on arrival at breeding colonies were significantly correlated. Both showed a marked decrease in 1998/99, after the El Niño of 1997/98. In most seasons from 1994/95 to 2001/02 crustaceans dominated the food, but the mass of chicks at fledging was significantly related to the contribution of fish to the diet.Afr. J. mar. Sci. 25: 475–48

UNUSUAL BREEDING BY SEABIRDS AT MARION ISLAND DURING 1997/98

In 1997/98, breeding at subantarctic Marion Island was exceptionally good for five species of seabirds capable of foraging over wide areas and for a tern. The number of king penguin Aptenodytes patagonicus chicks surviving to the start of spring in 1997 was considerably more than previously recorded. Greater numbers of wandering Diomedea exulans and grey-headed Thalassarche chrysostoma albatrosses, northern giant petrels Macronectes halli and Kerguelen terns Sterna virgata bred than previously recorded, and more southern giant petrels M. giganteus did so than in any other year since 1994. For southern giant petrels, reproductive success was higher than in any other year, as was survival of chicks of northern giant petrels. Conversely, for two seabirds that feed close to the island, gentoo penguin Pygoscelis papua and Crozet shag Phalacrocorax [atriceps] melanogenis, 1997/98 was a particularly poor breeding season. Gentoo penguins initiated breeding later than usual and fledged few chicks. The number of Crozet shags that bred decreased; probably about 25% of the adult population did not breed. For two species with an intermediate foraging range that eat mainly crustaceans, macaroni Eudyptes chrysolophus and eastern rockhopper E. chrysocome filholi penguins, breeding was not noticeably different from normal except that chicks of rockhopper penguins fledged with a slightly heavier mass than in other years. However, for both these penguins, the mass of adults on arrival at colonies decreased substantially in the following (1998/99) breeding season. The unusual breeding by most of the seabirds coincided with the El Niño Southern Oscillation (ENSO) event of 1997/98. This synchrony contrasts with lagged responses to ENSO events of seabirds that breed farther south in the Southern Ocean. Continued monitoring of seabirds over well-separated sites in the Southern Ocean may elucidate how climatic perturbations operating at a global scale impact seabirds in the region.Afr. J. mar. Sci. 25: 453–46

Sticking under wet conditions: the remarkable attachment abilities of the torrent frog, staurois guttatus

Tree frogs climb smooth surfaces utilising capillary forces arising from an air-fluid interface around their toe pads, whereas torrent frogs are able to climb in wet environments near waterfalls where the integrity of the meniscus is at risk. This study compares the adhesive capabilities of a torrent frog to a tree frog, investigating possible adaptations for adhesion under wet conditions. We challenged both frog species to cling to a platform which could be tilted from the horizontal to an upside-down orientation, testing the frogs on different levels of roughness and water flow. On dry, smooth surfaces, both frog species stayed attached to overhanging slopes equally well. In contrast, under both low and high flow rate conditions, the torrent frogs performed significantly better, even adhering under conditions where their toe pads were submerged in water, abolishing the meniscus that underlies capillarity. Using a transparent platform where areas of contact are illuminated, we measured the contact area of frogs during platform rotation under dry conditions. Both frog species not only used the contact area of their pads to adhere, but also large parts of their belly and thigh skin. In the tree frogs, the belly and thighs often detached on steeper slopes, whereas the torrent frogs increased the use of these areas as the slope angle increased. Probing small areas of the different skin parts with a force transducer revealed that forces declined significantly in wet conditions, with only minor differences between the frog species. The superior abilities of the torrent frogs were thus due to the large contact area they used on steep, overhanging surfaces. SEM images revealed slightly elongated cells in the periphery of the toe pads in the torrent frogs, with straightened channels in between them which could facilitate drainage of excess fluid underneath the pad

COUNTS OF SURFACE-NESTING SEABIRDS BREEDING AT PRINCE EDWARD ISLAND, SUMMER 2001/02

The first midsummer survey of surface-nesting seabirds at Prince Edward Island was conducted during December 2001. It was also the first census for most species since the early 1980s. Despite concerns about the impacts of longline fishing mortality on various albatrosses and giant petrels, there was no evidence that populations of these species had decreased. Indeed, the estimate of wandering albatrosses Diomedea exulans (Vulnerable) has increased significantly, making Prince Edward Island equal with Marion Island as supporting the largest single-island populations of this species. Species that underwent significant decreases were macaroni penguins Eudyptes chrysolophus (Vulnerable), Crozet shags Phalacrocorax [atriceps] melanogenis and Kerguelen terns Sterna virgata (Near-Threatened). The reasons for these decreases are unclear, but for macaroni penguins may be partly a consequence of competition for space with the burgeoning population of fur seals Arctocephalus spp. The 2001 survey increased the population estimates for Subantarctic skuas Catharacta antarctica, lightmantled sooty albatrosses Phoebetria palpebrata (Vulnerable) and southern giant petrels Macronectes giganteus (Vulnerable), mostly as a result of greater coverage than for previous counts. The 2001 survey confirms that Prince Edward Island remains a globally important breeding site for seabirds.Afr. J. mar. Sci. 25: 441–45

The inevitable youthfulness of known high-redshift radio galaxies

Radio galaxies can be seen out to very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that for any model of radio-galaxy evolution in which the luminosity decreases with time after an initial rapid increase (that is, essentially all reasonable models), all observable high-redshift radio-galaxies must be seen when the lobes are less than 10^7 years old. This means that high-redshift radio galaxies can be used as a high-time-resolution probe of evolution in the early Universe. Moreover, this result helps to explain many observed trends of radio-galaxy properties with redshift [(i) the `alignment effect' of optical emission along radio-jet axes, (ii) the increased distortion in radio structure, (iii) the decrease in physical sizes, (iv) the increase in radio depolarisation, and (v) the increase in dust emission] without needing to invoke explanations based on cosmology or strong evolution of the surrounding intergalactic medium with cosmic time, thereby avoiding conflict with current theories of structure formation.Comment: To appear in Nature. 4 pages, 2 colour figures available on request. Also available at http://www-astro.physics.ox.ac.uk/~km

DECREASE IN NUMBERS OF THE EASTERN ROCKHOPPER PENGUIN EUDYPTES CHRYSOCOME FILHOLI AT MARION ISLAND, 1994/95–2002/03

The number of eastern rockhopper penguins Eudyptes chrysocome filholi breeding at subantarctic Marion Island decreased from about 173 000 pairs in 1994/95 to about 67 000 pairs in 2001/02. During 1994/95–2002/03 pairs fledged on average 0.40 chicks per year, an amount thought insufficient to balance mortality of breeding adults, and there was a decrease in the mass at arrival at breeding colonies of both males and females. Except in 1997/98, the mass of chicks at fledging was less than that recorded at two other localities. These factors suggest an inadequate supply of food for rockhopper penguins at Marion Island. Decreases of rockhopper penguins at several other localities also have been attributed to inadequate food. Rockhopper penguins at Marion Island continued to feed mainly on crustaceans during chick rearing. There was a marked increase in the contribution of fish to the diet in 1999/00 that coincided with an increase in mass at arrival at colonies of both males and females. Trends in numbers of pairs breeding in different sections of Marion Island were not always consistent, indicating the need for island-wide monitoring to establish the overall trend. Afr. J. mar. Sci. 25: 487–49

Income differences in food consumption in the 1995 Australian national nutrition survey

Objective: To assess the relationships between an index of per capita income and the intake of a variety of individual foods as well as groups of food for men and women in different age groups. Design: Cross-sectional national survey of free-living men and women. Subjects: A sample of 5053 males and 5701 females aged 18 y and over who completed the Australian National Nutrition Survey 1995. Methods: Information about the frequency of consumption of 88 food items was obtained. On the basis of scores on the Food Frequency Questionnaire, regular and irregular consumers of single foods were identified. The relationships between regularity of consumption of individual foods and per capita income were analysed via contingency tables. Food variety scores were derived by assigning individual foods to conventional food group taxonomies, and then summing up the dichotomised intake scores for individual foods within each food group. Two-way ANOVA (income age group) were performed on the food variety scores for males and females, respectively. Results: Per capita income was extensively related to the reported consumption of individual foods and to total and food group variety indices. Generally, both men and women in low income households had less varied diets than those in higher-income households. However, several traditional foods were consumed less often by young high-income respondents, especially young women. Conclusions: Major income differentials in food variety occur in Australia but they are moderated by age and gender. Younger high-income women, in particular, appear to have rejected a number of traditional foods, possibly on the basis of health beliefs. The findings also suggest that data aggregation has marked effects on income and food consumption relationships.<br /

Advances in Pediatric Neurovirology

Viral infections of the pediatric central nervous system (CNS) encompass a broad spectrum of both perinatally and postnatally acquired diseases with potentially devastating effects on the developing brain. In children, viral infections have been associated with chronic encephalopathy, encephalitis, demyelinating disease, tumors, and epilepsy. Older diagnostic techniques of biopsy, viral culture, electron microscopy, gel-based polymerase chain reaction (PCR), and viral titer quantification are being replaced with more rapid, sensitive, and specific real-time and microarray-based PCR technologies. Advances in neuroimaging technologies have provided for earlier recognition of CNS injury without elucidation of specific viral etiology. Although the mainstay therapy of many pediatric neurovirologic diseases, aside from HIV, includes intravenous acyclovir, much work is being done to develop novel antiviral immunotherapies aimed at both treating and preventing pediatric CNS viral disease