A preliminary fish survey of the estuaries on the southeast coast of South Africa, Kayser’s Beach – Kei Mouth: a comparative study

A basic ichthyofaunal and physico-chemical survey of estuaries on the southeast coast of South Africa from Kayser’s Beach to Kei Mouth was undertaken during September and October 1996. Twenty-eight (28) estuaries have been identified along this stretch of coastline, and these were grouped into three types: small (<10 ha) predominantly closed estuaries, moderate to large (> 10 ha) predominantly closed estuaries, and predominantly open estuaries. Multivariate analyses revealed significant differences between estuarine types both in terms of their physico-chemical characteristics and fish communities. These features were consistent with those reported in other parts of the south and southeast coast. Overall, predominantly closed estuaries had a lower species diversity than predominantly open estuaries and smaller systems had a lower species diversity than moderate to large systems. Although differences were observed between estuarine types, most systems provided important habitat for a number of estuarine-dependent marine species as well as resident species, which were often recorded in high numbers. Many of these species were also endemic, which further emphasises the importance of these estuaries in maintaining ichthyofaunal diversity in the region. This survey represents one of the few fish surveys undertaken along this little-studied section of coastline.Keywords: ichthyofauna, estuarine survey, fish habitat, southeast coas

An assessment of the recreational fishery in the St Lucia estuarine system, KwaZulu-Natal, South Africa

St Lucia is one of the largest estuarine systems in Africa, and attracts thousands of anglers each year. Catch card data from the National Marine Linefish System for the years 1986–1999 were analysed to determine catch composition, catch per unit effort (cpue) and seasonality of catches by recreational anglers. Because not all anglers completed catch cards, estimates of total catch were made using additional data on the number of private boat outings, the number of boat trailers at boat slipways and the number of boats recorded entering the campsite gates during 1992 and 1993. In all, 27 fish families, constituting 55 species, were recorded by recreational anglers. Dusky kob Argyrosomus japonicus, spotted grunter Pomadasys commersonnii, perch Acanthopagrus berda, Natal stumpnose Rhabdosargus sarba, springer Elops machnata and mini-kob Johnius dorsalis were the most prominent species caught in terms of numbers and mass. Catch rates expressed numerically (fish angler-1 h-1) peaked during the summer and early winter. However, in terms of mass, catch rates peaked during late winter and spring, when there were increased landings of large dusky kob. Fluctuations in cpue were linked to salinity and estuary mouth conditions (i.e. mouth closure). Despite annual fluctuations in cpue, regression analysis revealed an overall downward trend for the dominant species (dusky kob and spotted grunter) and a gradual increase for stumpnose, perch and springer, but with the exception of stumpnose, these trends were not significant. Socio-economic aspects of the fishery were also investigated by conducting an independent boat-angler survey. The value of the recreational fishery, in terms of accommodation and direct angler expenditure, was estimated to be in the region of R9 million during 1992. Angler attitudes towards fishing regulations were positive and anglers generally had a good knowledge of the regulations for target species. Based on this assessment, a number of suggestions are made regarding the future management of the recreational fishery at St Lucia.Keywords: catch and effort, management, recreational angling, socio-economics, St Lucia estuarine systemAfrican Journal of Marine Science 2002, 24: 263–27

The Role of Temporal Relationships in the Transfer of Conditioned Inhibition

Two experiments with rats investigated the temporal relationships under which conditioned inhibition will transfer to an independently conditioned excitor (CS) in a summation test. Experiment 1 trained 2 simultaneous inhibitors with either a trace or delay excitatory CS. Transfer of inhibitory behavioral control depended on the temporal relationship of the transfer CS to the unconditioned stimulus (US). Experiment 2 extended these findings by training 2 inhibitors (1 simultaneous and 1 serial) with a single delay excitatory CS. Again, testing with trace and delay transfer CSs found that transfer of inhibitor control depended on the temporal relationship of the transfer CS to the US. In both studies, maximal inhibition was observed when the inhibitor signaled US omission at the same time as the transfer excitor signaled US presentation. The results are discussed in terms of the temporal coding hypothesis

Unblocking with Qualitative Change of Unconditioned Stimulus

Conditioned barpress suppression was used to examine the effects of qualitative changes in the unconditioned stimulus (US) between Phases 1 and 2 of a blocking paradigm. In Phase 1, rats received pairings of a conditioned stimulus (CS) with footshock. In Phase 2, experimental subjects received a single trial of the same CS or a different CS compounded with a second stimulus and followed either by a footshock or an ice water dunking. These two USs were equated in their potential to elicit conditioned suppression of barpressing. Less blocking of the second stimulus (i.e., unblocking) was observed in subjects that received a qualitative change in US between phases than in subjects for which the US was consistent between phases. This unblocking effect is discussed with respect to the differences between various models of conditioning and several prior successes and failures to demonstrate unblocking

Biological Significance as a Determinant of Cue Competition

Many researchers have noted the similarities between causal judgment in humans and Pavlovian conditioning in animals. One recently noted discrepancy between these two forms of learning is the absence of backward blocking in animals, in contrast with its occurrence in human causality Judgment. Here we report two experiments that investigated the role of biological significance in backward Mocking as a potential explanation of this discrepancy. With rats as subjects, we used sensory preconditioning and second-order conditioning procedures, which allowed the to-be-blocked cue to retain low biological significance during training for some animals, but not for others. Backward blocking was observed only when the target cue was of low biological significance during training. These results suggest that the apparent discrepancy between human causal judgment and animal Pavlovian conditioning arises not because of a species difference, but because human causality studies ordinarily use stimuli of low biological significance, whereas animal Pavlovian studies ordinarily use stimuli of high biological significance, which are apparently protected against cue competition

Advocating Scientism, 1963-2013

By the nineteenth century, scientism began to emerge as a worldview that sought to explain all phenomena through the scientific method to the exclusion of all other ways of knowing. These sentiments intensified with Charles Darwin’s discovery of evolution by natural selection. At the turn of the twentieth century, scientific discoveries increased exponentially, giving rise to a strong confidence that science could indeed describe everything. By 1960, certain scientists grew so confident in science’s descriptive ability that they started to advocate scientism. From 1963 to 2013, they advocated an antireligious, positivistic worldview through their popular works and warned of concurrent global conundrums such as the existence of nuclear weapons, global warming, and overpopulation. They envisioned a human future in space as a possible means to avoid earthly problems

Cue Competition as a Retrieval Deficit

Four experiments using rats as subjects investigated the claim of Williams (1996) that cue competition results from an associative acquisition deficit, rather than a performance deficit. In Experiment 1, extinction of an overshadowing stimulus following overshadowing treatment increased responding to the overshadowed stimulus, thereby replicating prior observations with new parameters. In Experiment 2, an overshadowed stimulus failed to support second-order conditioning unless the overshadowing stimulus received prior extinction treatment. Experiment 3 replicated the recovery from overshadowing effect seen in Experiment 1 using a sensory preconditioning procedure. Most important, in Experiment 4 an overshadowed stimulus failed to block conditioned responding to a novel CS, but blocking by the overshadowed cue was observed following posttraining extinction of the overshadowing stimulus. These results, as well as those of Williams, are discussed in terms of traditional and more recent acquisition-focused models as well as an extension of the comparator hypothesis ( Denniston, Savastano, & Miller, 2001)

Structural Elements Of Lipidic Inhibitors Of Phospholipase A2

Phospholipases A2 (PLA2) are a family of enzymes that release fatty acids from phospholipids and play varied and important roles in the biology of all organisms. Secreted phospholipases A2 (sPLA2) are the largest subfamily of PLA2. sPLA2 expression levels have been positively correlated to the severity of multiple inflammatory diseases. Many sPLA2 inhibitors have been developed and tested, however, none have shown to be clinically effective and specific against individual enzymes within this family. In this study we discovered an inhibition phenomenon in a widely used sPLA2 enzymatic assay. The enzymatic rate of reaction of sPLA2 group IIA from Crotalus adamanteus was significantly reduced when negatively charged lipids were added at very low mole fractions. This inhibition phenomenon did not occur if the lipid added was either positively charged or polar but neutral. These results suggest that the standard assay should be re-optimized to prevent this nonspecific inhibition and that the literature may need to be reevaluated

Beyond Law And Policy: Reaffirming The Role Of Student Affairs.

no abstract availabl

A National Survey Of Managed Honey Bee 2011-12 Winter Colony Losses In The United States: Results From The Bee Informed Partnership

Estimates of winter loss for managed honey bee (Apis mellifera) colonies are an important measure of honey bee health and productivity. We used data from 5,500 US beekeepers (5,244 backyard, 189 sideline and 67 commercial beekeepers) who responded to the April 2012 Bee Informed Partnership Winter Colony Loss Survey and calculated loss as the difference in the number of colonies between October 1, 2011 and April 1, 2012, adjusting for increases and decreases over that period. In the US, the total colony loss was 22.5% for the 2011-12 winter; 45.1% (n = 2,482) of respondents reported no colony loss. Total loss during 2011-12 was substantially lower than loss during 2010-11 (29.9%). Of the 4,484 respondents who kept bees in 2010-11 and 2011-12, 72.0% reported that the loss during 2011-12 was smaller or similar to the loss during 2010-11. There was substantial variation in total loss by state (range 6.2% to 47.7%). The average loss per beekeeping operation was 25.4%, but the average loss was not significantly different by operation type (backyard, sideline, commercial). The average self-reported acceptable loss per respondent was 13.7%; 46.8% (n = 2,259) of respondents experienced winter colony losses in excess of the average acceptable loss. Of beekeepers who reported losing at least one colony during 2011-12, the leading self-identified causes of mortality were weak condition in the fall and queen failure. Respondents who indicated poor wintering conditions, CCD, or pesticides as a leading cause of mortality suffered a higher average loss when compared to beekeepers who did not list these as potential causes