Digestion rates of prey eaten by intertidal sea anemones from the south-western Cape,South Africa

Digestion rates were determined for natural prey items offered to each of seven species of sea anemones found at Wooley’s Pool in False Bay and to the single species (Bunodactis reynaudi) recorded at Biouberg on the Atlantic coast of the south-western Cape, South Africa.This was done by examining prey items removed from the coelenterons at regular intervals after feeding and assessing their degree of digestion according to a predetermined scale. There was considerable variation in the gut retention times between different anemone species offered the same prey types, with Actinia equina consistently showing the shortest gut retention times (12 h for amphipods, 15 h for pelecypods and 23 h for isopods). Of the various prey categories tested, amphipods tended to be the most rapidly digested group, while molluscs and echinoderms usually remained in the coelenteron the longest. Mean gut retention times in B. reynaudi, the only species found both in False Bay (17°C) and on the cold west coast (12°C) were markedly longer (72 vs 60 h and 43 vs 30 h for pelecypods and gastropods respectively) at the lower temperature.     

Aspects of the biology of three benthic-feeding teleosts from King’s Beach,Algoa Bay

The lengths, abundance patterns and feeding habits of three species of benthic-feeding teleosts, Lithognathus mormyrus, Lithognathus lithognathus and Umbrina capensis from King’s Beach, Algoa Bay are presented. Multiple regression analysis was used to elucidate the influence of the physical environment on the abundance of L. mormyrus. The feeding habits of these species were analysed on a quantitative basis by means of gravimetry and the frequency of occurrence of prey items.     

Diet composition and breeding cycle of blacktail,Diplodus sargus capensis (Pisces: Sparidae), caught off St Croix Island,Algoa Bay,South Africa

The contents of the alimentary tracts of D. sargus capensis were analysed to establish diet composition. The importance of analysing stomach, intestine and total alimentary tract, separately, is emphasized. D. sargus capensis is an omnivore preying on lower intertidal and shallow subtidal benthic species. Cirripedia and algae were the most important groups and constitute ca. 60% of the total dietary composition. Ulva sp., Perna perna and Balanu, spp. were prefered species. A new index for ranking prey items, which combines the modified points method and the frequency of occurrence method, is suggested. It is especially useful for omnivorous fish where prey items sucl as seaweed and colonial organisms are difficult to enumerate. Ambosexual individuals differentiate into functional males or functional females. Active spermatogenesis in the ovo-testis suggests a special type of protandric development. D. sargus capensis has an extended breeding cycle with a peak spawning period from October to December.     

A mammal survey of the Serra Jeci Mountain Range,Mozambique, with a review of records from northern Mozambique’s inselbergs

The mountains of northern Mozambique have remained poorly studied biologically until recent years with surveys covering a variety of taxonomic groups highlighting their biological and conservation value. Even so, the medium and large mammal fauna remains poorly known and to date no systematic mammal surveys have been published from any of Mozambique’s mountains. We present results of a medium and large mammal survey of Serra Jeci’s Mt Chitagal, Mt Sanga and the Njesi Plateau in Niassa, northern Mozambique; the first mammal diversity data collected from these isolated mountains. We recorded 27 mammal species, of which six represent range expansions; Sykes’s monkey (Cercophitecus mitis), Mozambique dwarf galago (Paragalago granti), Smith’s red rock hare (Pronolagus rupestris), lesser cane rat (Thryonomys gregorianus), rock hyrax (Procavia capensis) and African buffalo (Syncerus caffer). We also reviewed and collated records of medium and large mammals from previously published fieldwork on northern Mozambique’s mountains, amounting to a total of 34 large mammal species from seven montane areas, highlighting the lack of mammalian knowledge in Mozambique’s Afromontane habitats.     

Dactylobiotus luci,a new freshwater tardigrade (Eutardigrada: Macrobiotidae) from theRwenzori Mountains,Uganda

A new freshwater eutardigrade, Dactylobiotus luci is described from a permanent marsh pool (Zaphania’s Pool) at 4225 m elevation in the Alpine zone of the Rwenzori Mountains, Uganda. The new species is most similar to D. dervizi Biserov, 1998 in the shape of the egg processes, absence of papillae and absence of eyes, but differs from it mainly by a different appearance of macroplacoids, by having tips of the egg processes usually sharp, not divided and more slender, and by several morphometric characters of eggs and adults. The new species was found in fairly acidic (pH < 6) Sphagnum-Carex fens bordering/extending into the pool. So far, it has only been recorded in one other high-elevation water body in Rwenzori in a similar habitat.     

Species diversity and size ranges of cephalopods in the diet of jackass penguins from Algoa Bay,South Africa

An analysis of cephalopod remains collected from jackass penguin Spheniscus demersus regurgitations and stomachs at St Croix Island, Algoa Bay, in 1976 and 1977 revealed the presence of three cephalopod species. Most common was Loligo reynaudi, with Heterotuthus sp. and Argonauta argo constituting trace items. Beak measurements were used to estimate dorsal mantle lengths and wet masses of cephalopods taken by penguins. The dominant cephalopod taken by penguins was the same species as that harvested by commercial fisheries. Despite an overlap in the size range of squid taken by penguins and trawlers, penguins tended to take smaller squid and did not take the larger squid landed by trawlers. The seasonal occurrence of squid in the penguin diet in 1976 and 1977 was the opposite of the abundance of squid in the area as reflected by trawler landings. This is explained in terms of the abundance and preference for other prey items. It is suggested that penguins take fish in preference to squid because of the relatively higher energy content and food value of fish.     

Ant species richness of fynbos and forest ecosystems in the southern Cape

The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in the fynbos negatively affected ant species richness. Ant species richness in the Afromontane forest decreased from the drier to the wetter sites. The aggressive alien ant species, Iridomyrmex humilis, has not invaded natural areas to any great extent.     

Systematic status of Platypleura stridula L. and Platypleura capensis L. (Hornopter,Cicadidae)

Although synonymi2ed for many decades, the Linnaean species Platypleura stridula and P. capensis are biologically distinct, differing in their host plant and habitat preferences, geographical distribution and calling songs. There are also morphological differences between the two taxa which parallel the differences in their biology. P. capensis should therefore be accorded specific rank.     

Prédation and prey selectivity by Argyrosomus hololepidotus (Osteichthyes: Sciaenidae) in south-eastern Cape waters of South Africa

Argyrosomus hololepidotus (kob) is a top predator in the shallow marine environment of the south-eastern Cape. There is considerable change in prey taken over the size range of predators examined (256-1701 mm). Young A. hololepidotus are planktivorous taking swarming mysids, but as they grow they become piscivorous, feeding on both pelagic and demersal prey associated with soft sediments. The pelagic cephalopod Loligo reynaudi is also taken by large specimens. Prey selection varies with locality and time of year. A field experiment in which the prey were compared with fish caught in a small-mesh net revealed a preference for some slow-moving demersal species. The length distributions of dominant prey species are given and these clearly show that larger prey are preferred by larger predators.     

>Utilization of shallow subtidal bays associated with warm temperate rocky shores by the late-stage larvae of some inshore fish species,South Africa

>This work describes the utilization of shallow, subtidal bays, associated with rocky shores, by the late-stage larvae and early juveniles of some common inshore fishes. Larval and early juvenile fishes were collected in seven small bays (30–50 m wide) between Port Alfred (33°36’S, 26°53’E) and Hamburg (33°17’S, 27°29’E), using a modified, beach seine net (500 µm mesh). Four bays were sampled weekly during peak fish spawning (September–November 2004) to firstly assess whether larval fishes occur in these previously-unstudiedhabitats and secondly, to assess the extent of this utilization in terms of species occurrence, abundance and potential nursery function. An additional three replicate bays, situated >50 km away near Bira were used for comparison. In total, 14 fish families represented by 26 taxa were recorded but the catch was dominated by a small suite of common species. Bays were extensively utilized by Sparidae (>Diplodus capensis >and >Sarpa salpa>), and to a lesser extent by Clinidae (>Clinus superciliosus>), Mugilidae (>Liza >spp.) and Kyphosidae (>Neoscorpis lithophilus>). Mean CPUE of larvae was high and exceeded 900 individuals per seine haul. Larval abundance peaked at 4000 larvae per haul and at these times, was dominated only by the two sparid species. Abundance of sparid larvae exceeds that recorded for these species in surf zones, estuaries or the shallow nearshore habitatssampled to date in temperate South Africa by an order of magnitude. Larval abundance was significantly higher during new moon sampling throughout the study period, but was not significantly different between repeated samples collected per site on each fieldtrip. The length-frequency of larvae utilizing the bays was dominated by postflexion stages ranging 7–14 mm SL. Length-frequency distribution of >Diplodus, Sarpa, Clinus, Sparodon, Neoscorpis >was indicativeof grow-out and use of bays as interim nurseries. The nursery function of these bays is supported by gut analysis of a sub-sample of the dominant species, >Diplodus capensis, >which showed that these larvae were actively feeding in the area, predominantly on copepods. This work prompts further research on shallow habitats associated with rocky shores particularly the shelter and feeding role that these under-studied habitats are playing in the early life history of coastal fishes.     

Estimating Cape hare occupancy and abundance in southern Tunisia using spotlighting data

This study outlines the importance of integrating spotlighting data and occupancy modelling to estimate the spatial occupancy, abundance and habitat preferences of Cape hares Lepus capensis in southern Tunisia. Exploring the spatial distribution pattern of this species is problematic because of its nocturnal and secretive behaviour. In order to overcome these constraints, we used spotlight surveys on equidistant points along tracks to collect presence/absence data. Using a likelihood-based approach, we estimated occupancy and relative abundance of Cape hare populations in three national parks: Sidi Toui, Bouhedma and Jbil. We also combined the three parks in a single area to represent ‘southern Tunisia’ for investigating the factors affecting its distribution pattern. Sidi Toui showed the highest occupancy and relative abundance values (88.84 ± 10.95% and 7.97 hares km^?2, respectively). Bouhedma was also recognised as high-quality hare habitat with occupancy and relative abundance values of 61.70 ± 11.70% and 2.85 hares km^?2, respectively. The lowest occupancy (49.65 ± 26.25%) and relative abundance (2.10 hares km^?2) estimates were encountered in Jbil. The combined parks model suggested that part of the distribution pattern of Cape hares can be explained by habitat quality. Spatial occupancy over southern Tunisia showed a positive relationship between its occurrence and the availability of Poaceae and Plantaginaceae.     

A survey of the fish fauna of Transkei estuaries Part Two: The Mbashe Estuary

The species composition, seasonal abundance and spatial distribution of the fish fauna of the Mbashe estuary (8 km long) was determined by means of gill nets. During the 37 month survey period, 2908 fish (2319,8 kg), comprising 27 species, were caught. The family Mugilidae, representing 58,8% of the numbers and 57,4% of the biomass, predominated the catches. In terms of biomass M. cephalus, A. hololepidotus and P. commersonnii were the most important species. Seasonal patterns for 10 of the 27 species were observed. M. cephalus, A. hololepidotus and L. amia were more abundant in spring/summer, E machnata and V. buchanani in spring, P. commersonnii and L. tricuspidens increased numerically in winter and M. capensis in autumn, Johnius dussumieri and Valamugil cunnesius were rare in winter and summer, respectively. Largest catches were made in the middle reaches of the estuary followed by the upper and lower reaches, respectively.     

Distribution of Euphausiid Crustaceans from the Agulhas Current

Twenty-nine euphausiid species were collected during the three cruises of the S.A.S. Natal in 1958. Of these only Stylocheiron microphthalmia had not previously been taken in South African waters. The commonest euphausiid represented in the collection is a larval series which is provisionally linked with Euphausia recurva or E. mutica. The vertical and horizontal distribution of each species is re-corded and seasonal and latitudinal variation discussed. Stylocheiron suhmii, S. microphthalma and Thysanopoda tricuspidata are proposed as indicators of Agulhas Current water and Nyctiphanes capensis and Euphausia lucens as indicators of water not of Agulhas Current origin. The largest number of euphausiids was found off Port Elizabeth during both summer and winter.     

Problems presented by geographical variation in the African vine snakes,genus Thelotornis

Analysis of variation in 771 specimens of the genus Thelotornis A. Smith (Colubridae) confirms the absence of intergradation between the taxa kirtlandii (Hallowell) and oatesii (Gunther) in northern Angola and southern Zaire, so 7. capensis A. Smith is accepted as a full species. The western race 7. capensis oatesii shows very little variation, but the eastern populations of 7. capensis are extremely variable and it is convenient to revive the name mossambicanus (Bocage) for the populations which occur from central Mocambique northwards. T. c. oatesii hybridizes extensively with T. c. capensis and 7. c. mossambicanus in southeastern Rhodesia and adjacent Mocambique. Northern populations of 7. c. mossambicanus show features of 7. kirtlandii, but these are apparently primitive characters retained since the original partition of Thelotornis into western and eastern forms. The highlands of Kenya and northern Tanzania isolate these northern mossambicanus from the nearest kirtlandii populations in Uganda.     

South-western extension of the known range of two freshwater shrimps,Caridina nilotica (Roux) and Macrobrachium petersi (Hilgendorf), in South Africa

Two freshwater shrimps, Caridina nilotica (Roux) and Macrobrachium petersi (Hilgendorf), were collected in the Gamtoos River in the eastern Cape, representing a southwestern range extension for both. This is the first known record of these species west of Port Elizabeth, and also the first record of an overlap of their distribution ranges with that of the Cape river shrimp, Palaemon capensis (de Man).     

Observations on the reproductive cycles of Cellana capensis (Gmelin, 1791) and Patella concolor Krauss, 1848 (Gastropoda: Prosobranchia: Patellidae)

The reproductive periodicities of the patellid limpets Cellana capensis and Patella concolor were determined from changes in macro-and microscopic appearance of the gonads over a 14-month period. Both species appear to have protracted breeding periods with several peaks in spawning activity. Problems encountered with the application of standard sampling and analytical methods to species with such cycles are discussed.     

The ichthyoplankton assemblage of the Algoa Bay nearshore region in relation to coastal zone utilization by juvenile fish

The nearshore ichthyoplankton of Algoa Bay was sampled at six stations over a two-year period between 1980 and 1982. Larvae of 26 families of teleosts were identified with Gobiidae constituting 48,0%, Engraulidae 26,7% and Clupeidae 12,1% of all larvae sampled. Caffrogobius spp., Engraulis capensis and Etmmeus teres were the dominant species. Representatives of families such as Sparidae and Mugilidae which numerically dominate juvenile nursery areas in Algoa Bay were not abundant in the nearshore ichthyoplankton. The various taxa occurring in the ichthyoplankton are discussed in terms of distribution of adults and juveniles, breeding biology and available information on early life history. The paucity of larvae of coastal species with pelagic eggs is highlighted and, with reference to the findings of other workers and local oceanographic conditions, a possible spawning strategy is suggested.     

Residency and small-scale movement behaviour of three endemic sparid fishes in their shallow rocky subtidal nursery habitat,South Africa

The residency and small-scale movements of early juveniles (<175 mm fork length) of three sparid fish species were examined in the shallow subtidal zone along a 500 m stretch of rocky coastline near Schoenmakerskop (Eastern Cape Province, South Africa). A total of 12 blacktail (Diplodus capensis), 12 zebra (Diplodus hottentotus) and six white musselcracker (Sparodon durbanensis) were tagged using visible implant elastomer (VIE) tags. Underwater observations in four shallow rocky subtidal gullies and adjacent areas were made using snorkeling gear on a total of 37 days spanning 13 field trips over spring low tide periods between January and August 2006. The VIE tagging method was well suited to individually tag small juvenile fish with minimum disturbance. In general, the degree of residency of juveniles in the shallow rocky subtidal zone was species specific and dependent on the size of individuals. Juvenile zebra displayed the highest degree of residency followed by white musselcracker and blacktail, with re-sightings recorded on 53%, 40% and 10% of observation days, respectively. The high degree of residency by early juvenile sparids renders them vulnerable to localized coastal perturbations and climate change.     

Seasonal variation in the diet of Cape clawless otters (Aonyx capensis) in a marine habitat

Seasonal changes in the diet of Cape clawless otters Aonyx capensis feeding in the surf zone in False Bay, Western Cape Province, South Africa, were investigated by spraint (faecal) analysis. The most common prey species, during all seasons, was the Cape rock crab, Plagusia chabrus. The next most important prey species was the Cape rock lobster, Jasus lalandii, with the fish species Clinus superciliosus being equally important in winter. Other prey were fresh-water crabs, Potamonautes perlatus, octopus, Octopus granulatus, and 17 other species of fish, frogs and mammals. In winter and autumn the most important prey category was fish while in spring and summer, crustaceans were the most important. Diversity of prey was lowest in winter, increasing through the seasons from spring to autumn.