Tsitsikamma National Park Research Articles

Movement pattern and home range of Roman Chrysoblephus laticeps

The movement behaviour of adult Roman Chrysoblephus laticeps (Sparidae) was investigated using mark-and-recapture techniques in the Goukamma Marine Protected Area (GMPA) and the Tsitsikamma National Park (TNP) on the South African temperate south coast. The study was designed to improve the spatial resolution of previous studies on Roman that suggested residence behaviour, but which could not estimate home range size. A combination of conventional barbed dart tags and visible implant fluorescent elastomer (VIFE) tags were used to tag Roman from a skiboat in the GMPA. Roman were tagged with dart tags from the shore in the TNP. Of the recaptures, 61% were within 50m of the tagging position, confirming that Roman are very resident. A few fish, independent of size and sex, moved distances up to 4km. A model was developed to quantify the degree of residence, by accounting for tag loss, mortality and the distribution of recovery effort. The probability of a Roman remaining within an area of 1ha is 0.91 (GMPA) and 0.94 (TNP) — such a small home range suggesting that individual Roman would benefit from small MPAs.

Stock separation and life history of Argyrozona argyrozona (Pisces: Sparidae) on the South African east coast

Fishery independent biomass surveys and commercial linefish catch returns were used to elucidate the spatial patterns of carpenter Argyrozona argyrozona distributed along the South African continental shelf. Two distinct areas of abundan ce ere determined, one on the central and the other on the eastern Agulhas Bank. Tagging studies revealed little exchange between them. Nurseries were identified in Algoa Bay on he eastern Agulhas Bank and on the central Agulhas Bank (CAB). Early juveniles (<100mm total length) on the CAB were found offshore in the vicinity of the Alphard Bank. They were found to move inshore with growth and then back offshore as they approached maturity. Juveniles in Algoa Bay dispersed both eastwards and westwards with growth. Otoith readability and growth rates varied between regions, with fish from the Eastern Cape (Port Elizabeth and Port Alfred combined) having the lowest average percentage error (4.82 vs 5.33 and 7.03) and the slowest growth rates. Size-at-50 % mturity (L50) varied regionally, female fish in the Eastern Cape maturing at a smaller size (L50 = 206mm fork length) than in the Tsitsikamma National Park (L50 = 292mm) or the CAB (L50 = 267mm). Mass-at-length varied between regions, with carpenter in the Park having the highest mass-at-length and those in the Eastern Cape having the lowest. Based on the distribution of carpenter, variability in otolith readability, mass-at-length, variation in growth and size-at-maturity, it is concluded that carpenter exist as two separate stocks and should be managed accordingly.

Currents along the Tsitsikamma coast, South Africa, and potential transport of squid paralarvae and ichthyoplankton

In July 1998, a bottom-mounted Acoustic Doppler Current Profiler was deployed at 36m depth in the centre of the Tsitsikamma National Park on the eastern Agulhas Bank, South Africa. The purpose was to investigate transport of chokka squid Loligo vulgaris reynaudii paralarvae hatched on the inshore spawning grounds (<60m) and ichthyoplankton spawned within the park. Analysis of the first 12 months of data (July 1998–June 1999) shows that surface flow was mainly eastward (alongshore), with a maximum velocity (u-component) of +115cm s−1 and an average of +24cm s−1. Generally, velocity decreased with depth, with a maximum bottom velocity (u-component) of +65cm s−1 and an average of +10cm s−1. Data from a nearby thermistor array show that the water column was usually isothermal during winter (July–September), with bottom flow in the same direction as the surface layer. In summer (December–March), vertical stratification was most intense, and surface and bottom flows differed in velocity and direction. Potential net monthly displacements calculated for three depths (5m, 23m and 31m) indicate that passive, neutrally buoyant biological material (e.g. squid paralarvae, fish eggs and larvae) would likely be transported eastwards in the surface layer for eight of the 12 months, and would generally exceed distances of 220km month–1. Displacement in the bottom layer was more evenly distributed between east and west, with net monthly (potential) transport typically 70–100km, but reaching a maximum of 200km. Wind-driven coastal upwelling, prevalent during the summer, causes the surface layer of the coastal counter-current to flow offshore for several days, resulting in potential displacement distances of 40km from the coast. These results suggest that squid paralarvae hatched on the inshore spawning grounds are not generally transported towards the 'cold ridge', a prominent semi-permanent oceanographic feature of cold, nutrient-rich upwelled water, where food is abundant, and that fish larvae, whether from the surface or bottom layer, are exported beyond the boundaries of the Tsitsikamma National Park.

Influence of sample design on estimates of growth and mortality in Argyrozona argyrozona (Pisces: Sparidae)

Abstract In order to determine the minimum sample size required to accurately estimate growth and mortality, and to assess the effects of using either random or stratified sampling procedures, a large sample of Argyrozona argyrozona ( n = 618) was collected during February and March 1998 from the central Agulhas bank. To investigate the influence of monthly sampling and integer ageing on growth estimation, monthly samples were collected for a period of 1 year and a single large sample was collected during February and March 1998 in the Tsitsikamma National Park. Decimal and integer ageing of monthly samples produced similar estimates of growth ( p > 0.05), fishing mortality ( F ) and spawner biomass-per-recruit (SB/R). Estimates of growth ( p > 0.5), F and SB/R derived from random monthly ( n = 298) and single annual random samples ( n = 300), and based on integer ageing, were also very similar. Random and stratified draws from the large Agulhas bank sample revealed that a minimum of 300 random samples or at least 10 fishes per 2 cm size class (i.e. n = 193) were necessary to provide reliable estimates of growth, F and SB/R. To optimise the trade-off between cost and parameter precision, A. argyrozona are best monitored with a stratified sample of 10 fishes per 2 cm size class that is taken during the spawning season.

Alternate explanations of the dispersal pattern of galjoen Dichistius capensis

The movement behaviour of galjoen Dichistius capensis (>250mm total length) was studied by using a tag and recapture technique. A total of 25 191 galjoen was tagged at four sites in South Africa. Three of the sites were in fully protected reserves (two in the De Hoop Marine Protected Area, one in the Tsitsikamma National Park), whereas the fourth site was at the Cape Peninsula where fishing is permitted. In all, 2 174 fish were recaptured, some of them several times. The vast majority of fish were caught at the site of release. After correcting for differences in recovery effort between the release sites and other areas, it was estimated that 95% of tagged fish remained at the release site. The remaining 5% moved throughout the South African range of galjoen, which was separated from the Namibian range. There was no evidence to suggest that movement is linked to season, age or sex. Although not territorial, galjoen do hold home ranges, which were estimated to be no larger than 1.38km in extent, but probably much smaller. Two likely models, the polymorphic and the tourist, are advanced to explain the movement behaviour. The polymorphic model is a combination of two movement patterns, one resident and another nomadic. The balance between the two may represent a mixed evolutionary stable strategy. The tourist model does not differentiate between fish. Each fish spends its time at a small number of widely separated sites, moving between them as conditions dictate. The tag and recovery data do not favour one model above the other unequivocally.

Ochthebius (s.str.) capicola (Coleoptera) re-discovered in the Cape Peninsula, South Africa

New distributional records and ecological observations are presented for the Cape endemic hydraenid Ochthebius capicola. Considered extinct on the Cape Peninsula, the species has been re-discovered at two adjacent locations as well as at a new site in Tsitsikamma National Park, Eastern Cape. New species associations are recorded, in conjunction with observations confirming this species' preference for algae-covered rock surfaces in the hypersaline pools of the supralittoral zone. Provisional internationally-endangered status for this species was examined but considered dependent on future data. It was considered likely that the beetle may be insufficiently recorded, due to its atypical habitat requirement. A synopsis of the taxonomic status of this species and Ochthebius rubripes is given. Notes on both species are provided, as well as a record of sympatric occurrence.

Age and growth of Argyrozona argyrozona (Pisces: Sparidae) in a marine protected area: an evaluation of methods based on whole otoliths, sectioned otoliths and mark-recapture

Argyrozona argyrozona is an important component of the South African commercial linefishery. The purpose of this study was to develop a reliable protocol for estimating age and calculating growth. Methods based on both otoliths and mark-recapture data were investigated. Transverse sagittal sections from the Tsitsikamma National Park (TNP) showed clear opaque and translucent growth increments. Marginal growth zone analysis and mark-recapture of chemically tagged fish (Oxytetracycline) revealed that these were deposited on an annual basis: opaque in summer and translucent in winter. The first translucent check was shown by daily increment counts to mark the completion of the first annulus (i.e. not a juvenile/false check). Within reader (between counts) and between readers average percentage error (APE) was 5.3 and 1.8, respectively, showing that readability of carpenter otoliths is high. Comparison between whole and sectioned otoliths showed that the former significantly underestimated the age of fish older than 10 years ( P<0.01). The maximum age obtained from whole otoliths was 16 years while that obtained from otolith sections was 27 years. Based on realistic L ∞ estimate and the distribution of residuals, the three parameter von Bertalanffy growth function adequately fitted the observed length-at-age data derived from otolith sections. Growth rates did not differ significantly between sexes ( f=2.217, P=0.09). Growth of carpenter in the TNP is described by the following equation: L t=623(1− e −0.08(t−1.96)) A large proportion (68%) of the individual growth rates derived from mark-recapture data were below those predicted by the otolith based von Bertalanffy growth model ( P<0.01). This was attributed to the negative influence of external tags as hydroids, frequently occurring on the tags of recaptured fish, were observed to cause severe lesions and in some cases, extensive fin damage. This brings into question the use of mark-recapture studies to calculate growth of some species.

Adult Movement and Larval Dispersal of Argyrozona Argyrozona (Pisces: Sparidae) from a Temperate Marine Protected Area

Adult emigration and larval dispersal of carpenter Argyrozona argyrozona from the Tsitsikamma National Park (TNP), South Africa, were investigated using mark-recapture data and Acoustic Doppler Current Profiler measurements of currents. Tagging data showed that adult carpenter were mainly resident, with a small proportion (7%) leaving the TNP in both easterly and westerly directions. There was no relationship between fish movement patterns and fish size or time-at-liberty. Current patterns suggest that eggs and larvae spawned within the TNP are mainly transported eastwards towards established nursery grounds; the median estimated distance moved was 299 km (range 42–561 km) in 30 days (time to flexion). Given this pattern of ichthyoplankton dispersal, together with the fact that adult carpenter within the TNP displayed a high degree of residency and that they are much more abundant than in adjacent fishing grounds (catch per unit effort being 23 times greater), it appears that the TNP protects a viable carpenter spawner population capable of seeding adjacent fishing grounds.

Dynamics of the Fishery for Galjoen Dichistius Capensis, With an Assessment of Monitoring Methods

The dynamics of the fishery for galjoen Dichistius capensis were investigated at four sites in South Africa from 1987 to 2000. At three sites, which were protected from fishing, Koppie Alleen, Lekkerwater (both in the De Hoop Marine Protected Area) and Tsitsikamma National Park, fishery-independent surveys were conducted. Data for the Cape Peninsula (the fourth site) were obtained from records kept by a recreational angler. Catch per unit effort (cpue) was highest at De Hoop and lowest at Tsitsikamma. At De Hoop, cpue varied significantly among anglers, months, years and gear type. The mortality rate was greater at the exploited site than at protected sites, where mortality rates were taken as estimates of natural mortality. Tag and recovery data were used to estimate density and catchability. Fishing mortality rates were very high, whether inferred from size distributions or from the product of effort counts and the catchability coefficient. Such high rates can be sustained only through refuges. Variation in fishery parameters among habitats and the high variance in cpue data suggest that an effective monitoring programme will need to be intensive. To provide adequate stock assessments, fishery-dependent surveys should be augmented by studies in marine protected areas.

Freshwater fishes of Tsitsikamma National Park

This study aimed to determine the distribution and relative abundance of freshwater fishes in the Tsitsikamma National Park. Fish assemblages in six river systems were sampled in 2001, with a total of 323 fish from eight species recorded. Indigenous fish collected included four freshwater species (Pseudobarbus afer, Pseudobarbus tenuis, Sandelia capensis, Anguilla mossambica), three estuarine species (Monodactylus falciformis, Caffrogobius gilchristi, Myxus capensis), and one alien (Micropterus salmoides). One additional indigenous species (Galaxias zebratus) and two aliens (Salmo trutta, Oncorhynchus mykiss) could potentially occur within the park. The topography and locality of the park presents a unique opportunity to meaningfully conserve the endangered P. tenuis as well as other fish characteristic of the eastern reaches of the Cape Floristic Region. Management action is required to minimise opportunities for further establishment and spread of alien fish species and to conserve indigenous fish assemblages within the park.

The role of the Tsitsikamma National Park in the management of four shore-angling fish along the south-eastern Cape coast of South Africa

The role of the Tsitsikamma National Park (TNP) in the management of four important shore-angling fish (Diplodus sargus capensis, Diplodus cervinus hottentotus, Pachymetopon grande and Dichistius capensis) was evaluated using data obtained from two independent studies conducted over a similar time period, along the south-eastern Cape coast of South Africa. Shore-angling catches were analysed from (i) data gathered from roving creel surveys conducted in the open access areas from Kei Mouth to Stil Bay between April 1994 and February 1996, and (ii) monthly research fishing conducted in the TNP between February 1995 and January 1997. Results from a tag and release study conducted within a small area (c. 5 km) of the TNP revealed that the four study species were resident. Size frequency analyses revealed that the mean individual length (and mass) of the four species was significantly higher in the TNP than in the open access areas. Catch per unit effort data suggest that the species were between five and 21 t...

Movement patterns of red steenbras Petrus rupestris tagged and released in the Tsitsikamma National Park, South Africa

Movement patterns of red steenbras Petrus rupestris were obtained from fish tagged and released in the Tsitsikamma National Park, South Africa. Of 217 fish tagged, 38 were recaptured. Juveniles (<700 mm FL) were resident, whereas adults (>700 mm FL) migrated in a north-easterly direction towards the Transkei coast.

Nearshore surface current patterns in the Tsitsikamma National Park, South Africa

The pattern of surface currents in the Tsitsikamma National Park, South Africa, was studied with holey-sock drogues released in batches of up to four at a time, from 1996 and 1998. Drogues were left to drift for either 6 or 24 h, while recording position and time. The majority of drogue movements were longshore, either eastward or westward; they usually travelled with similar direction and velocity. In most instances, westward movements were slightly offshore and were sometimes associated with a rise in the thermocline. Eastward movements were, on average, slightly slower, with an onshore component, sometimes associated with a lowering of the thermocline. The remaining trials showed some variability between drogues and were characterized by reduced velocity and unstable direction, indicating either the presence of horizontal turbulence or a current reversal. Current and wind were poorly correlated. Current directions were sustained for at least four days, indicating that short-lived ichthyoplankton, originating in the 70-km park, may be dispersed beyond its boundaries.

An updated check list of the ichthyofaunal species assemblage of the Tsitsikamma National Park, South Africa

This work summarises ichthyological research in the Tsitsikamma National Park (TNP) over the past 20 years, and an updated species check list of fishes has been compiled. A total of 202 species of fishes from 84 families has been recorded within the boundaries of the national park. All species which have been included were identified from visual transects, rotenone collections, estuarine surveys, ichthyoplankton surveys, mark/recapture studies and personal observations. The ichthyofauna is a diverse assemblage of chondrichthyans and teleosts, 75 (37.1) of which are components of commercial and recreational fisheries along the east coast. Surveys also indicate that the TNP provides refuge to all life history stages for 17 of the commercial and recreational teleost species. The need for more detailed collections of previously neglected teleost and chondrichthyan groups is recognised. The number of species and diversity demonstrates that the TNP appears not only to afford protection to exploited fish species, but also fulfills one of the basic requirements of Marine Protected Areas@that of conserving biodiversity (of fishes).

Shore-angling catches in the Tsitsikamma National Park, 1989-1995

Catch card returns completed by visitors and locals angling in the fishing area of the Tsitsikamma National Park between 1991 and 1995, as well as results of scientific fishing in the whole park between 1989 and 1991 were analysed. Species composition, catch per unit effort (cpue) and seasonality were determined. Seventy-six percent of the 1 147 catch cards suitable for analysis were submitted by visiting anglers, who caught a total of 1 638 fish weighing approximately 1 522 kg during 4 654 angler-hours. This was almost double the 948 fish, weighing about 611 kg, landed during 1 863 angler-hours by local anglers. A total of 709 fish weighing 774 kg was recorded during the 461 scientific fishing angler- hours. The mean annual cpue of visitors was lower than that of locals (35 @ 1 SE vs. 55 @ 3 SE fish/I 00 angler-hours), while the cpue recorded during the sci- entific fishing throughout the park was 154 fish/100 angler-hours. Species most frequently caught by visitors were Sarpa salpa (22.6 ), Amblyrhynchotes honckenii (19.6 ) and Diplodus sargus capensis (6.7 ), while the catches of locals were dominated by S. salpa (36.7 ), Boopsoidea inornata (21.8 ) and Pomatomus saltatrix (10.4 ). Outside the open fishing area scientific catches were dominated by D. sargus capensis (20 ), Cheimerius nufar (13 ), Pachymetopon grande (9 ) and Dichistius capensis (6 ). Fewer than 2.5 of the bony fish caught in the fishing area weighed more than 3 kg. Catch rates of most species varied seasonally, with the overall cpue of both visitors and locals peaking between October and April. The cpue in the fishing area of the park was at least 2.5 times lower than that recorded in the De Hoop Nature Reserve and Terrace Bay in the Skeleton Coast National Park. However, the cpue recorded during scientific fishing throughout the Tsitsikamma National Park compared favourably with that recorded in other protected areas.

Ichthyoplankton distribution and dispersal in the Tsitsikamma National Park marine reserve, South Africa

The nature of ichthyoplankton distribution within the Tsitsikamma National Park marine reserve was investigated in an attempt to evaluate the potential for export of larvae of commercially and recreationally important reef species to adjacent, exploited areas. Monthly, inshore ichthyoplankton samples were taken using Bongo nets over an 18-month period. Sampling sites were located over areas of high-profile reef and sand, Current-meter measurements of the area were used to determine current velocity, direction and reversal periodicity. Statistical analysis of the data was performed independently for larvae from four families: Blenniidae, Gobiesocidae, Sparidae and Engraulidae. Results suggested that blenniid and gobiesocid larvae practised active position retention throughout their pelagic phase, while this feature was less defined in sparid and engraulid larval distribution. Using larval distribution and current-meter information, projected dispersal distances for spa rid larvae, the family containing the most target commercial and recreational angling species, were estimated. The results suggest that sparid larvae are exported from the reserve to adjacent, exploited areas.

A first list of plant-parasitic nematodes from the Tsitsikamma National Park, with descriptions of two new species of the subfamily Criconematinae

Plant nematodes recorded during surveys in the Tsitsikamma National Park are listed and two new Criconematinae species are described. Females of Criconemoides silvicola spec. nov. have the first three or four annuli separated from the following annuli by a discontinuity, dorsally and ventrally fused submedian lobes which are connected by a ridge laterally, 106-127 smooth, retrorse annuli with numerous irregularities and three to 11 anastomoses, a sharp-pointed tail with last few annuli extended and a 41-49 Urn-long stylet. Ogma tuberculatum spec. nov. females have 53-59 retrorse, tuberculate annuli with six longitudinal rows of broad tuberculate scales, two lip annuli, first with greater diameter than second and a 84-102 urn-long stylet. Males without stylet, with four lines in each lateral field. Juveniles with 61- 68 retrorse annuli, bearing 12 to 14 longitudinal rows of large, broad, rounded, minutely tuberculate, overlapping scales.

South Africa's Tsitsikamma National Park as a protected breeding area for the commercially exploited chokka squidLoligo vulgaris reynaudii

South Africa's Tsitsikamma National Park is within the general spawning area for Loligo valgaris reynaudii. Spawning squid use at least 10 areas within its boundaries, sporadically throughout the year, but mainly in early summer. Spawning occurred either on sand or low-profile rocky reef at depths between 22 and 35 m. Concentrations varied between a few hundred spawning pairs, with small and scattered egg mops, to thousands of spawning pairs with a large central egg bed surrounded by smaller egg mops. Squid paralarvae were captured within the boundaries of the Park, and squid tagged there moved to other spawning sites generally eastwards of it, where they were recaptured by commercial fishermen. The Park provides protection and undisturbed breeding sites for a portion of the spawning stock for part of the spawning period, and exports squid biomass through larval dispersal. It is unlikely that the Park markedly enhances the squid fishery, because spawning there is much less frequent than in open fishing areas.

A Preliminary Ichthyoplankton Survey of the Tsitsikamma National Park

An ichthyoplankton survey using bongo nets was conducted within the Tsitsikamma National Park over an 18-month period between January 1991 and July 1992. Four sampling stations along the coast were chosen, approximately 5 km apart. At each station four samples were taken along a transect perpendicular to the coast, between 0,35 km and 3,8 km offshore. Horizontal tows were taken at three and 15 m below the surface over reef and sand substrata respectively. Larvae belonging to 24 of the 35 families and 55 of the 97 species known to occur in the area were captured. Engraulid larvae completely dominated the catches while amongst the reef-associated taxa sparids and blenniids were prominent. Seasonally occurring cold upwelling events impacted negatively on egg and larval abundance. Mean values for egg and larval abundances were 1207 and 282 per 100 m3 respectively. A relationship between larval number and plankton volume was revealed. Most larvae captured were between 2,0 and 20,3 mm (SL), and in the preflexio...

Blue duiker &lt;i&gt;Philantomba monticola&lt;/i&gt; densities in the Tsitsikamma National Park and probable factors limiting these populations

Numbers of blue duikers recorded on 157 and 28 variable width transect counts, done over a two year period in the Tsitsikamma Coastal National Park (TCNP) and Tsitsikamma Forest National Park (TFNP) respectively, did not differ significantly {P &gt; 0,10) with seasons (summer v. winter). Population density estimates from transects were similar to those from game drives (0,18 v. 0,19 duikers/ha (TCNP) and 0,13 v. 0,17 duikers/ha (TFNP); P &gt;0,10), higher than from faecal pellet counts (P &lt; 0,10) and at least three times lower than estimates from the Kenneth Stainbank Nature Reserve and Umdoni Park in Natal. Factors contributing to the low population densities in the Tsitsikamma national parks were investigated. Twentyseven and seven percent of leopard (25) and caracal (12) scats respectively analyzed contained blue duiker remains, but predator numbers appear to be low. Forest characteristics were investigated, and results from this and other studies suggest that undergrowth cover does not markedly influence blue duiker densities in the southern Cape forests. Field and stomach analysis indicate that blue duikers feed primarily on freshly fallen leaves and fruit, and are selective foragers. In the Tsitsikamma national parks (TNPs) the frequency of occurrence of trees known to be palatable to duikers are low, while less than 45 percent of the dominant tree species fruit fully annually. This apparent scarcity of food, the low numbers of antelope species and individuals in these forests and results from duiker research in Zaire, suggest that habitat rather than predation is limiting duiker numbers in the Tsitsikamma national parks.