Age and growth of Cape stumpnose Rhabdosargus holubi (Pisces: Sparidae) in the Eastern Cape, South Africa

Rhabdosargus holubi (Steindachner, 1881) is a small (maximum size = 450 mm total length; Heemstra and Heemstra 2004) sparid that is distributed along the south-east coast of Africa from St Helena Bay, South Africa, to Maputo, Mozambique (Götz and Cowley 2013). Spawning occurs in the nearshore marine environment primarily during winter, specifically May–August in KwaZulu-Natal (KZN) (Wallace 1975) and July–February in the South-Eastern Cape (Whitfield 1998). Individuals reach 50% sexual maturity at approximately 150 mm standard length (SL) in the Eastern Cape (Whitfield 1998). The early life stages are transported by the south-westward-flowing Agulhas Current, and recruit as post-flexion larvae and early juveniles into estuaries during late winter and early summer (Blaber 1974). The warm temperatures and high nutrient levels in estuaries favour fast growth (Blaber 1973a), and fish spend their first year of life in these environments, migrating back out to sea after reaching approximately 120 mm SL. Some individuals remain trapped in closed estuaries, where they may reach sizes greater than 200 mm SL (James et al. 2007a). Rhabdosargus holubi is the dominant estuarine-dependent marine teleost species recorded in permanently open and temporarily open/closed estuaries in the warm-temperate region, which spans the south, south-east and east coast of South Africa (Harrison 2005). The species is also an important component of the linefishery in many SouthAfrican estuaries (10–15.6% by number) (Pradervand and Baird 2002), particularly in Eastern Cape estuaries (Cowley et al. 2003). These figures underestimate the presence of R. holubi, as most individuals making use of estuaries are young, feeding predominately on filamentous macroalgae and diatom flora, and are generally too small to be caught with hook and line (De Wet and Marais 1990). James et al. (2007b) showed that R. holubi made up 34–92% of the annual seine-net catch in the East Kleinemonde Estuary. Rhabdosargus holubi is also important in the KZN shorebased linefishery, representing 4.6% of the total landed catch (Dunlop and Mann 2012)

Severity of Giardia infection associated with post-infectious fatigue and abdominal symptoms two years after

<p>Abstract</p> <p>Background</p> <p>A high rate of post-infectious fatigue and abdominal symptoms two years after a waterborne outbreak of giardiasis in Bergen, Norway in 2004 has previously been reported. The aim of this report was to identify risk factors associated with such manifestations.</p> <p>Methods</p> <p>All laboratory confirmed cases of giardiasis (n = 1262) during the outbreak in Bergen in 2004 received a postal questionnaire two years after. Degree of post-infectious abdominal symptoms and fatigue, as well as previous abdominal problems, was recorded. In the statistical analyses number of treatment courses, treatment refractory infection, delayed education and sick leave were used as indices of protracted and severe <it>Giardia </it>infection. Age, gender, previous abdominal problems and symptoms during infection were also analysed as possible risk factors. Simple and multiple ordinal logistic regression models were used for the analyses.</p> <p>Results</p> <p>The response rate was 81% (1017/1262), 64% were women and median age was 31 years (range 3-93), compared to 61% women and 30 years (range 2-93) among all 1262 cases. Factors in multiple regression analysis significantly associated with abdominal symptoms two years after infection were: More than one treatment course, treatment refractory infection, delayed education, bloating and female gender. Abdominal problems prior to <it>Giardia </it>infection were not associated with post-infectious abdominal symptoms. More than one treatment course, delayed education, sick leave more than 2 weeks, and malaise at the time of infection, were significantly associated with fatigue in the multiple regression analysis, as were increasing age and previous abdominal problems.</p> <p>Conclusion</p> <p>Protracted and severe <it>giardiasis </it>seemed to be a risk factor for post-infectious fatigue and abdominal symptoms two years after clearing the <it>Giardia </it>infection.</p

Cyanobacterial lipopolysaccharides and human health – a review

Cyanobacterial lipopolysaccharide/s (LPS) are frequently cited in the cyanobacteria literature as toxins responsible for a variety of heath effects in humans, from skin rashes to gastrointestinal, respiratory and allergic reactions. The attribution of toxic properties to cyanobacterial LPS dates from the 1970s, when it was thought that lipid A, the toxic moiety of LPS, was structurally and functionally conserved across all Gram-negative bacteria. However, more recent research has shown that this is not the case, and lipid A structures are now known to be very different, expressing properties ranging from LPS agonists, through weak endotoxicity to LPS antagonists. Although cyanobacterial LPS is widely cited as a putative toxin, most of the small number of formal research reports describe cyanobacterial LPS as weakly toxic compared to LPS from the Enterobacteriaceae. We systematically reviewed the literature on cyanobacterial LPS, and also examined the much lager body of literature relating to heterotrophic bacterial LPS and the atypical lipid A structures of some photosynthetic bacteria. While the literature on the biological activity of heterotrophic bacterial LPS is overwhelmingly large and therefore difficult to review for the purposes of exclusion, we were unable to find a convincing body of evidence to suggest that heterotrophic bacterial LPS, in the absence of other virulence factors, is responsible for acute gastrointestinal, dermatological or allergic reactions via natural exposure routes in humans. There is a danger that initial speculation about cyanobacterial LPS may evolve into orthodoxy without basis in research findings. No cyanobacterial lipid A structures have been described and published to date, so a recommendation is made that cyanobacteriologists should not continue to attribute such a diverse range of clinical symptoms to cyanobacterial LPS without research confirmation

The age and growth of hottentot seabream Pachymetopon blochii before and after the South African linefish state of emergency in 2000

The hottentot seabream Pachymetopon blochii is a small-sized (maximum 2.67 kg) sparid endemic to southern Africa. It is an important target in South Africa’s Western Cape traditional linefishery, particularly in the absence of more valuable pelagic species (such as Thyrsites atun and Seriola lalandi). In 2000, South Africa’s linefishery was declared to be in a state of emergency, and commercial fishing effort was consequently reduced by 70%. A subsequent increase in stock biomass and intraspecific competition, coupled with environmental changes, were hypothesised to have thereafter altered the growth rate of hottentot, from 2000 to 2010. This study aimed to revise outdated age–growth models for the hottentot by using modern techniques (sectioned otoliths), and to compare age–growth relationships before and after the declared linefish state of emergency. The maximum age observed was 19 years, with no difference in the growth rate between sexes (p = 0.39–0.43) or time-periods (p = 0.96). Although the growth rate did not change, there is evidence that the age structure of the stock changed between time-periods as a result of changes in fishing pressure between 2000 and 2010. The enhanced recent growth model for hottentot, described as Lt = 418.063 (1 – e−0.104(t –[−4.709])) (pooled sexes; n = 206), indicates a considerably slower growth rate for this species than was proposed previously using whole otoliths and has major implications for effective stock management.Keywords: age structure, gonochoristic fish, growth model, intraspecific competition, linefishery, Sparidae, Western Cape, whole otolith

Mainstream Party Strategizing On Corruption Issues – The Case Of Italy

Research on niche parties have not thoroughly explored dynamics between niche and mainstream parties. The model for mainstream party strategy provided by Meguid is complemented by research on the influence of far-right parties on their party systems. What strategy a mainstream party chooses towards a niche party is likely to be influenced by the type of niche party. Anti-corruption parties are of particular interest due to their massive electoral successes in Eastern Europé. Italy is identified as the critical case for Western Europe and the hypothesis that anti-corruption parties are not successful in long-existing party systems. The study shows that Italian mainstream parties have politicized corruption to a surprisingly large extent given the widespread pessimism over their capabilities in fighting corruption, but the evidence is inconclusive with regard to how exact strategy choices are affected by the level of niche party threat. The cases not in line with the predictions of Meguid’s model are most likely explained by that dealing with corruption is toxic for a party that is under corruptionallegations