A detailed literature review of relevant Ulva biology and chemical composition is included. Marine algae are known to produce a wide range of volatile organic compounds that are primarily used in chemical communications. These compounds are released in seawater and act as either pheromones or allelochemicals. Aldehydes have been reported to be the main group of volatile compounds in green algae Ulva. Cultivation of Ulva as feed on abalone farms in South Africa has been a success but there has been little research on the chemistry of South African Ulva. This study aims to investigate the potential effects of environmental variables and grazing on the chemical profile, and specifically on the aldehyde-type natural products produced (δH 9.00 - 10.50) by laboratory cultured Ulva using ¹H NMR spectroscopy and multivariate statistical analysis. Ulva armoricana was cultured at different salinities: 5, 10, 20, 25 and 35 ‰ (all ± 0.1 ‰) and nutrient treatments: 100 % Provasoli ES medium (high nutrient supply) and 0 % Provasoli ES medium (low nutrient supply) at 10 °C and 15 °C for 6 days under constant light (39.2 ± 0.43 μmol photons m⁻² s⁻¹) on a 16:8 hours light:dark photoperiod. Natural grazing (using Tricolia capensis Dunker) and artificial grazing (stimulated by scissors) was performed to determine their effects on the chemical composition of Ulva armoricana. Results obtained show that grazing and nutrient experiments mostly affected the aromatic, hydroxylic and carbonyl compounds regions, while salinity change mostly affected the alcohol, ester and phenolic regions. The aldehyde profiles included a prominent peak at δH 9.76 in almost all treatments that was provisionally identified as hexanal. Ulva armoricana grown at 10 °C under low nutrient condition and in a medium with salinity at 25 ‰ was found to be the ideal condition to produce a higher intensity of the main aldehyde.

A combination of satellite and in situ data were used to infer the occurrence and temporalspatial variability of upwelling near Angoche. The data were derived from MODIS SST and Chl-a between 2003 and 2007, in situ moored underwater temperature recorder at a depth of 18 m for the period 2003ô2007 and two shipboard surveys providing CTD and XBT data in December 2008 and in August 2009 in the northern Mozambique region. The results con rm that shelf edge upwelling occurs along the northern coast of Mozambique near Angoche between 15 and 18oS, covering an area of approximately 68 000 km2. The upwelling signature was not strong at the surface. Two upwelling core regions were identi ed: (1) the shelf core region and (2) the slope core region. At the shelf core region upwelling was more persistent than at the slope core upwelling. The upwelling displayed seasonal variation between persistent downwelling (warm water) between AprilôJuly and intermittent upwelling (cool water) events between AugustôMarch. Generally the upwelling lasted for a period of about two months but, shorter periods between 8 and 30 days were also observed. The driving mechanism for the shelf edge upwelling o northern Mozambique was determined from satellite observations (NOAA/NCDC) of blended sea surface wind data, and by multi-satellite (AVISO) altimeter sea surface anomaly data between 2003 and 2007 and also during the two cruise surveys in December 2008 and August 2009. These data showed upwelling is in part wind-driven in response to the northôeasterly (NE) monsoon weak-wind velocities between AugustôMarch in the austral spring-summer. The intermittent nature of the upwelling season is also partly due to uctuations in wind direction during the NE monsoon winds. Eddies appear to play a limited role in driving the upwelling.

There have been no quantitative studies of fish species associated with the submarine canyons of the north east coast of South Africa. These canyons offer protection to coelacanths Latimeria chalumnae, fish of commercial importance, and a number of protected and endemic species. A fish survey was conducted by remotely operated vehicle (ROV) that captured video footage at depths between 60 m and 160 m. Seven canyons (Island Rock, South Island Rock, Wright, Jesser, Diepgat, Leadsman and Chaka) and one deep reef (Diepgat Deep Reef) spread along 78 km of shelf break were surveyed. Fish were identified and counted in 1143 30-second video segments. Patterns in diversity and abundance were investigated with respect to canyon, depth, and habitat type. The survey found 52 fish species from 23 families. The families Serranidae and Sparidae were well represented. The first submarine images of the critically endangered Seventy†Four seabream are particularly noteworthy. Only three Myliobatidae species represented the Chondrichthyans. Variation in Shannon-Wiener species diversity (H') was influenced by the diversity of habitat (Kruskall†Wallis p<0,0001) and depths (Kruskall†Wallis p<0,0001). Mann†Whitney post hoc tests showed cave to have a higher H' than sandy plain (p<0,001) and wall (p<0,001). H' for margin was greater than sandy plain (p=0,001) and wall (p<0,001). H' for rock outcrop was greater than sandy plain (p=0,006). Fish diversity increased with increasing depth until 90m, thereafter diversity decreased with subsequent depths. Habitat (Permanova p=0,0031) had the strongest influence on fish community composition. No north†south separation in terms of fish diversity (H') among canyons was detected. The results were consistent with similar studies. All canyons were adequately sampled as the rate of discovery of additional species per sample was ≤1%. A minimum of 80 30-second samples per canyon is recommended to survey fish. The survey methods employed during this study are recommended for surveying deep reef fish to allow for meaningful comparative studies.

Includes bibliographical references. / Zandvlei is a small, seasonally closed, urban estuary situated 20 km south of Cape Town, and been subjected to many physical changes, including the construction of a rubble weir, canalisation of the Estuary mouth, construction of a marina and hardening of the banks with concrete. These changes have facilitated the expansion of an invasive reef-building polychaete, Ficopomatus enigmaticus. This study quantifies long term changes in the abundance of F. enigmaticus in Zandvlei and investigates historical changes in the salinity and invertebrate community. The standing stock of F. enigmaticus in the Marina da Gama has increased from 11.80 t in 1989 to 50.03 t in 2012 due both to an increase in the total area colonised by F. enigmaticus, and the dry mass of worm per m2 . There has also been a general trend of increased salinity in the system since 1989, with an increase of 4% recorded at the head of the Estuary in 2011. This study provides the first record of the infauna associated with F. enigmaticus in Zandvlei, which comprises 16 species. One of these is the hitherto unrecorded alien bryozoan, Conopeum seurati. Further research is required to understand the effects of long-term salinity change on the growth of F. enigmaticus and the role of F. enigmaticus as an ecosystem engineer.

Thirty-two specimens of the sixgill sawshark, Pliotrema warreni, were trawled near Bird Island in Algoa Bay on the Eastern coast of South Africa in April and May 2015. The specimens were examined for anatomical proportions, reproductive characteristics, diet, and parasite assemblages. Several external measurements were collected including mass, total length, standard length, girth, rostrum length, interoccular to pre-caudal length, first dorsal origin to second dorsal origin, first dorsal origin to pre-caudal origin, and mouth width. The equation for mass (g) vs. total length (mm) was ln(Mass)=0.2997*ln(TL)+2.0383 for females and ln(Mass)=0.3321*ln(TL)+1.941 for males. 1st Dorsal to 2nd dorsal origin length (DD) to total length equations for females and males were DD=0.2451*TL-26.677 and DD=0.2598*TL-34.535, respectively. Mean lengths and masses were 11.5% greater and 50.3% heavier in females than males, respectively. Females were on average, 994 mm (759 mm – 1283 mm) in length while males were 891.8 mm (763 mm – 1015 mm). Average mass for females was 1702.5 g (602.5 g – 3478.5 g) whereas males it was 1132.6 g (687 g – 1593.5 g). Based on these data both sexes display isometric growth. Males were determined to reach sexually maturity around 850 mm which is similar to that reported by Ebert et al., (2013) around 830 mm. Females were found to reach sexual maturity at 1000 mm which is 100 mm smaller than what is reported by Ebert et al., (2013). Stomach mass increased with total mass and total length regardless of sex (female R² = 0.507; male R² = 0.213 for length and female R² = 0.6123; male R² = 0996 for mass). Females consumed larger prey items in terms of mass and length as well as a higher quantity of prey than males presumably because they are the larger sex and have an increased need for nourishment to provide for pregnancy. Prey items were redeye round herring, Etrumeus whiteheadi (64.96% of the diet), a benthic shrimp species not identified (7.69%), and Cape horse mackerel, Trachurus trachurus capensis (0.85%). Despite strict adherence to the guidelines for age determination for elasmobranchs provided in the literature, the conventional method used which involved extensive cleaning of the vertebral centra with an array of chemicals, setting and cutting in an epoxy resin, and staining for microscopy, did not yield readable results which could be used to determine the ages of these sharks. The highest abundance of parasites were found in the stomachs. Three specimens of a cymothoid isopod was found externally. Two specimens of Ascaris sp. nematode were found in the visceral cavity. The remaining 18 parasites consisted of three Neoechinorhynchidae sp. of acanthocephalan and 15 Proleptus obtusus nematodes all of which were found inside the stomachs. Given the results of the parasite survey, males and females do not have the same parasites as females have four different species while males only have one. More collections from other areas and times of year are necessary to obtain a better description of the species.

Rising temperature caused by global warming alters physiology, phenology and/or distribution in a wide array of plant and animal species, which has dramatic knock-on effects at different levels of organisation. This study investigates the individual and interactive effects of temperature (18ᵒC, 22ᵒC and 30ᵒC) and additions of the macroalga Gracilaria gracilis (high and low) on the performance of the seagrass Zostera capensis, which occurs in Langebaan Lagoon, South Africa over a seven-week period. Results from the laboratory experiment revealed that G. gracilis did not significantly affect the performance of Z. capensis although temperature did result in greater leaf width, fouling and senescent biomass, as well as marginally greater leaf area and lower below-ground biomass at 30ᵒC. Increasing temperature also increased G. gracilis biomass, percent cover and fouling by microalgae. In addition, there was no interaction between temperature and the additions of Gracilaria. The overall findings of this study indicate that Z. capensis abundance is likely to decrease while G. gracilis will conversely increase in abundance in response to warming. Changes in abundance of those two ecosystem engineers highlight the possibility of a phase shift from a seagrass- to macroalgal-dominated state in Langebaan Lagoon.