Prawn Catch Research Articles

River discharge, fishing effort and catch composition of prawn fisheries in coastal Tanzania

This study examined the relationships between river discharge, fishing effort and catch composition of prawn fisheries in coastal Tanzania. Key assumptions were that river discharge would be a good indicator of rainfall and that the number of fishing vessels would reflect fishing intensity. We investigated whether reduced river discharge or increased fishing effort caused the collapse of the industrial prawn fishery in 2007, and which of these factors delayed recovery prior to reopening the fishery in 2017. The analysis showed a positive relationship between Catch Per Unit Effort (CPUE) and river discharge, with decreased river flow resulting in reduced prawn catches. The number of fishing vessels had little impact on CPUE before 2003, but thereafter CPUE declined even when fishing effort was reduced by 50%. A shift in trawl catches from a prawn-dominated fishery to a fish-dominated fishery was observed four years before the collapse. The trend in river discharge persisted below average (22 m³/s) between 2000 and 2007. Forewarning of low river discharge, changing trawl catch composition, and increasing effort may have led to developing proactive strategies to minimise the impact of a changing regime on fish stocks and dependent communities. We recommend establishing a monitoring system to anticipate similar events in the future.

Spatially structured relationships between white banana prawn (Penaeus merguiensis) catch and riverine flow in the Northern Prawn Fishery, Australia

Water resource development can lead to the significant alteration of natural flow regimes, which can have impacts on the many aquatic species that rely on both freshwater and estuarine environments to successfully complete their lifecycles. In tropical northern Australia, annual catches of commercially harvested white banana prawns (WBP) are highly variable in response to environmental conditions, namely rainfall and subsequent riverine flow. However, little is known about the spatial extent to which flow from individual rivers influences offshore WBP catch. In this study, we quantify how the relationship between WBP catch in the Gulf of Carpentaria is influenced by flow from the Mitchell River, Queensland Australia. We used a Bayesian framework to model both prawn presence and catch per unit effort, and found evidence that multiple components of the flow regime contribute to fishery catch. We also found evidence to suggest that the relationships between prawn presence and flow were spatially structured across the fishing ground. Our results suggest that attributing fishery catch to a single river remains challenging, though highlights the importance of maintaining natural flow regimes to support a highly valuable commercial fishery species in the face of potential water resource development.

Environmental functions of the Teknaf Peninsula mangroves of Bangladesh to communicate the values of goods and services

Mangroves are highly productive wetland ecosystems and extremely important coastal resources providing a variety of environmental goods and services, which are vital to our socio-economic development. To evaluate the role of mangroves, a total of 75 semi-structured interviews were conducted with coastal community, resource user, government official, NGO personnel, researchers, and private entrepreneur to gather primary and secondary information. Results indicated that in the past 30 years there has been planted about 1,460 ha of euryhaline mangroves under different management regimes. Teknaf peninsula mangrove influenced two key variables viz., productivity and physical structure which direct other ecological processes. The variable ‘productivity’ provide suitable habitat for nursery, growth, migration through recycling waste and nutrients. The respondents identified 13 mangrove resource user groups in Teknaf peninsula which shows high dependency to mangroves goods. The catch of finfishes, shrimps and prawns, crabs, molluscs, etc. from the mangroves area contributes value to the small-scale fisheries. The knowledge gained from the information content of the Teknaf peninsula mangroves ecosystem contributes value to scientific and educational community. In particular, it means that environmental goods and services provided by the Teknaf peninsula mangroves are rarely produced independently and the multiple interdependencies involved in providing such environmental supports.

BIOECOLOGY OF GIANT FRESHWATER PRAWNS (MACROBRACHIUM ROSENBERGII) IN THE BILAH RIVER, LABUHANBATU DISTRICT, NORTH SUMATERA

Giant freshwater prawns (Macrobrachium rossenbergii) were still been the favorite prawn catch of local fishermen in the Labuhanbatu district. This raises concerns for the survival of these animals. Therefore, it is necessary to conduct a study to obtain bioecological information on this giant freshwater, giant prawns in the Bilah river especially inform about condition the abundance based on gonad maturity levels, and the growth patterns of Giant freshwater prawns (M. rossenbergii). This study was conducted at 3 stations around the Bilah river. These stations were determined using a purposive sampling method. Furthermore, sampling was carried out using fishing nets. After that, the caught fish were analyzed to find out the Fulton’s condition factor, the abundance of prawns based on gonad maturity levels, and the growth patterns. The results of growth patterns analysis which calculate from the relationship of carapace length and body weight of M. rossenbergii caught were showed negative allometric category (b value 1.88 to 2.577). Meanwhile, the abundance of giant freshwater prawns based on gonad maturity levels for males and females were dominated by immature prawns (ranging from 46.15 to 54.65%).

IPTEK BAGI MASYARAKAT PEMANFAATAN TURBOJET DRIVE PRODUK 3D PRINTING UNTUK PERAHU NELAYAN SUNGAI DESA SEMPAN-BANGKA

Province of Bangka Belitung Islands has a large number of natural resources, including mining products, marine products, agricultural products, plantation products, and river products. One of the river products is fish and giant prawns which have high economic value which can be found in Bangka district, one of the places or rivers in Sempan village, Pemali sub-district. The river fishermen in the Pemali village fish and shrimp traditionally. The problem that occurs in these partners is that the boat still uses oars, this of course greatly slows down the movement in the river so that the catch of fish and giant prawns is small. Survey results on river fishermen partners on Sempan village, Pemali Bangka sub-district obtained data on the demand for a boat propulsion engine with low fuel consumption or a small engine displacement. The purpose of science and technology for river fishing communities is to increase the productivity of the catch of giant fish and prawns and as a means to save themselves from predators (crocodiles) when fishing for fish and shrimp in the river. The specific target of this IbM activity is expected to establish a cooperative and mutually beneficial relationship between partners and proposers from educational institutions. Partners get the right technology in the form of Turbojet Drive, 3D Printing product with a fuel-efficient engine. Agreed to propose to replace the boat propulsion system which originally used wooden oars to be replaced with a special “Turbojet Drive 3D Printing Product” propulsion with a fuel-efficient 58 cc engine. By replacing the offered boat propulsion, it is hoped that the targets and objectives of this IbM can be achieved and the catch of fish and giant prawns will increase. Thus, it is hoped that the standard of living of river fishermen will increase by using the appropriate technology offered by the proposing team.

Refining tickler chains for penaeid trawls

Tickler chains are simple additions to the ground gears of benthic trawls that can improve the catches of some target species, albeit with considerable variability. The purpose of this study was to decipher some of the technical variability associated with tickler chains used with generic, paired trawls targeting school prawns, Metapenaeus macleayi. In the first of two experiments, single tickler chains were either attached between the trawl otter boards or the wing ends and compared against each other and a control trawl (no tickler chain). Attaching the tickler chain to the otter boards significantly reduced wing-end spread and the trawled area without significantly affecting catches of school prawns. By comparison, attaching the tickler chain to the wing ends maintained spread and resulted in significantly more school prawns being caught (by 1.11 ×) than in the control trawl, and also fewer numbers of one teleost species, pink-breasted siphonfish, Siphamia roseigaster. In experiment two, a single tickler chain was compared against one with multiple chains and one with a double chain; all attached at the wing ends. Trawls with the multiple- and double-tickler chains had the same wing-end spread as those with the single tickler chain, while retaining up to 1.17 × more school prawns, and for the double-chain tickler, 45% fewer southern herring, Herklotsichthys castelnaui. The results are attributed to mechanical and visual stimuli affecting school prawns and some fish, respectively, and support maximising the surface area of tickler chains within the wing ends as a means for improving penaeid-trawl species selectivity without affecting swept area.

Impact of water development on river flows and the catch of a commercial marine fishery

AbstractThe growing demand for freshwater resources has led to dam construction and water diversions in a majority of the world's large rivers. With an increasing demand for freshwater, trade‐offs between water allocations and the preservation of ecological connections between terrestrial and marine ecosystems are inevitable. The ecological links formed by rivers flowing into the ocean benefit many commercially fished species. The degree to which different species and the livelihoods of fishers are negatively impacted by changes in river flows due to water extraction or diversion is important for management across terrestrial and marine boundaries. Our objective was to predict how changes in freshwater flows from three wet–dry tropical rivers in northern Australia, that is, the Mitchell, Gilbert, and Flinders rivers, affect the commercial banana prawn (Penaeus merguiensis) catch. We used a novel spatiotemporal Bayesian approach to model the effects of river flows and key climate drivers on banana prawn catch. We then predicted how the loss of flow due to water extraction or diversion affected prawn catch. Our analyses of three water development scenarios found that catch was most impacted by water extraction during low flows. The impact of water extraction was greatest for a scenario with dams on the Mitchell River, where we predicted catch would decline by 53% during a year with low flow. Overall, our results imply that maintenance of low‐level flows is a crucial requirement for sustained fishery yields. We suggest that water managers must balance agricultural demand for water during drier years against the impact of water extraction on prawn fisheries during low‐flow years. Protecting low‐level flows during drier years is a priority for maintaining terrestrial–marine linkages for adjacent marine fisheries.

From past to future: understanding and accounting for recruitment variability of Australia’s redleg banana prawn (Penaeus indicus) fishery

Abstract Understanding recruitment variability in marine fisheries has benefits for the stock management and dependent fishers’ ability to plan their income. Here, we overview past and new research on the complex recruitment dynamics of redleg banana prawns Penaeus indicus in Australia’s Joseph Bonaparte Gulf to assess themes dating back to the time of Hjort and identify new challenges. During 2015 and 2016, redleg prawn catches and catch per unit effort decreased to anomalously low levels, suggesting a substantial decrease in prawn biomass. We hypothesized that low catches could be explained by temporary drops in sea level and rainfall potentially reducing the ability of postlarvae to reach their nursery ground. We contend that very bad prawn catch years may be predicted using two variables that are possible drivers of recruitment—the January Southern Oscillation Index and the combined January to February cumulative rainfall. However, due to challenges in verifying and defining such environmental relationships for inclusion in a stock assessment, we propose development of a harvest strategy framework to support management recommendations. Our study highlights the increasing role of anthropogenic climate change in exaggerating the impacts of environmental drivers on recruitment processes and the need to also focus on multidisciplinary research.

Improving penaeid-trawl efficiencies via ground gear with tickler chains

Penaeid trawls often have poor ecological efficiencies measured as unwanted bycatches (with high discard mortality) and <100% effectiveness for all penaeids interacting with the ground gear (with some escape mortality). This study investigated the utility of varying ground-chain size (8- vs 10-mm diameter (Ø) stainless-steel chain) and the present or absence of a tickler chain (4-mm Ø) for improving efficiencies an Australian fishery diurnally targeting school, Metapenaeus macleayi and eastern king prawns, Penaeus plebejus. There were no treatment effects on wing-end spread and therefore areas trawled. Irrespective of the tickler chain, increasing the ground-chain Ø reduced catches of total penaeids (by 14%) and jellyfish, Catostylus mosaicus (by 39%)—results speculatively attributed to variation in ground contact and/or a slightly higher footrope in trawls with the 10-mm Ø chain. By comparison, installing the tickler chain had no effect on eastern king prawns, but increased catches of school prawns (by 1.13×) and bycatches of blue swimmer crabs, Portunus armatus (1.52×; a species with a low discard mortality) and jellyfish (1.23×), while reducing bycatches of two species with high discard mortalities: southern herring, Herklotsichthys castelnaui (by 38%) and squid, Uroteuthis sp. (37%). The results were attributed to the tickler chain producing (1) mechanical stimuli that augmented the capture of benthic-orientated school prawns (but not eastern king prawns owing to diel variations in emergence from the substrata), blue swimmer crabs and jellyfish; and (2) visual stimuli that possibly enabled some southern herring and squid to detect the trawl and escape. The data show tickler chains can improve trawl efficiency for penaeids with at least some positive effects on bycatch that should be rationalised in terms of species-specific vulnerabilities to unaccounted fishing mortality.

Influence of top-panel orientation (lead-ahead) on targeted and incidental catches in a penaeid trawl

Various, low-cost modifications to the anterior sections of penaeid trawls have been shown to realise significant improvements in species selectivity. This study expands the existing options by quantifying the importance of top-panel orientation relative to the bottom panel (dictated by relative headline and footrope lengths; termed ‘lead-ahead' or ‘lead’) on targeted and incidental catches in an Australian penaeid-trawl fishery. Three trawls were compared in a double rig: (1) the conventional configuration with identical footrope and headline lengths (7.53 m) and a 200-mm diameter buoy attached to the latter (termed the ‘buoyed no-lead trawl’); (2) the same trawl, but with the buoy removed (‘no-lead trawl’); and (3) a trawl with the same headline length as above, but the footrope 1.14× longer, creating lead-ahead (‘lead trawl’). Between 11 and 26 deployments of each configuration were done over six fishing days. Compared to the buoyed no-lead trawl, both the no-lead and lead trawls had greater wing-end spreads and both caught less total bycatch (absolute and standardized weights ha–1 trawled reduced by up to 64 and 48 %, respectively) and fewer individual unwanted species, including jellyfish, Catostylus mosaicus (by up to 61 and 58 %) and southern herring, Herklotsichthys castelnaui (by up to 59 and 43 %). However, only the lead trawl maintained catches of the targeted school prawns, Metapenaeus macleayi. These target catches were reduced by 37 % in the no-lead trawl (without the buoy). The results imply a trawl without lead-ahead requires sufficient headline height to maximise catches of school prawns, but simply introducing lead-ahead and removing the buoy (lowering the headline) can maintain target catches while dramatically reducing bycatch. Similar subtle refinements may have application in other penaeid-trawl fisheries.

Predicting the impacts of freshwater-flow alterations on prawn (Penaeus merguiensis) catches

Modification of freshwater flow regimes can impact estuarine ecosystems at the receiving end of these flows. This is particularly true in tropical areas, such as the wet-dry tropics, where major freshwater flows in the wet season may result in prolonged and large-scale flooding, followed by periods of little or no flow during an extended dry season. Estuarine species, such as the commercially important prawn Penaeus merguiensis, have lifecycles adapted to seasonal flows. The potential effects of flow regulation on estimated catches of P. merguiensis were explored using a Bayesian belief network (BBN) model. Probability statements were generated about the ecological implications of different magnitudes of natural flow, as well as three water-extraction scenarios: 1) reduced flow in the wet season; 2) the introduction of flow in the dry season; and 3) the combination of scenario one and two. Thresholds of freshwater flow that affect the likelihood of high prawn catches in the fishery were identified, and the cumulative effects explored. This is the first time that these thresholds have been identified and the model suggests there is little capacity to regulate or modify the freshwater flow without reducing the probability of high prawn catches.

Refining a Nordmøre-grid bycatch reduction device for the Spencer Gulf penaeid-trawl fishery.

Incremental refinements were made to a generic Nordmøre-grid to minimise bycatches of blue swimmer crabs Portunus armatus and giant cuttlefish Sepia apama, while maintaining catches of western king prawns Melicertus latisulcatus in the Spencer Gulf penaeid-trawl fishery. These refinements involved varying bar spaces, escape-exit areas and guiding-panel lengths, and were compared against a conventional trawl. Catches of teleosts and M. latisulcatus largely remained unaffected by the changes. Maximum reductions in P. armatus and S. apama bycatches (both ~90%) were achieved with a Nordmøre-grid comprising 38-mm bar spaces, 0.81- or 1.05-m2 escape exits and a 2.7-m guiding panel. Catching fewer P. armatus should reduce abrasion and crushing of M. latisulcatus in the codend and so increase the value of this targeted species. While noting some unresolved operational concerns, these results demonstrate the potential improvements in selectivity in this fishery using a Nordmøre-grid, primarily by mechanical separation.

MEY for a short-lived species: A neural network approach

This paper develops a neural network approach to estimate ‘Maximum Economic Yield’ (MEY) for a short-lived species. Unlike long-lived species, short-lived species are often relatively resistant to fishing pressure, but overall stock availability and MEY can also vary considerably in these fisheries due to environmental factors, such as changes in ocean currents and the weather. We argue that the common CPUE approach results in economic overfishing (lost profitability) if the price of fish varies with catch and, if so, neural networks can provide a very useful ex-ante prediction for stock availability and estimates of MEY, depending on how environmental factors unfold. Our approach is illustrated using a case study for banana prawn catch in the Australian Northern Prawn Fishery. Results show the superiority in both data-fitness and the predictive capability of the neural network approach, helping to provide a more reliable rainfall-dependent measure of MEY, thus avoiding the risk of economic overfishing in the currently applied catch-rate or trigger strategy. The results enforce our view that the CPUE approach generally results in economic overfishing if fish price varies with the catch.

The Effectiveness of the Jones/Davis Type By-Catch Reduction Device (BRD) to Reduce Unintended Catch of Trawl Fisheries

Reduction by-catch of commercial fishing are become major concern, especially prawn trawl fisheries. By-catch reduction device developed to address that issue. However, there were trade-off problems regarding the implementation the BRD in trawl fisheries that is the effectiveness of the BRD. The performance of BRD was questionable on the effectiveness in term of reduction the by-catch and maintenance amount of target catch. This essay examines the performance of Jones-Davis type BRD to reduce by-catch and its impact to prawn catch in Cleveland Bay. An experimental fishing has been conducted (control-net and BRD-net; Pair-trawl method) to assess the effectiveness of by-catch reduction which examined with Wilcoxon Rank Test. The result shows that trawl equipped by BRD significantly reduce by-catch by 22.2% (Z = -4.6406, p-value = 0.0001) and retained prawn catch which was no significant difference inprawn catch between BRD and control nets (Z = -1.9218, p-value = 0.0546). Therefore, that evidence could be argued to convince about the BRD benefits to commercial prawn trawl fisheries.

Confounding effects of knot orientation in penaeid trawls

This study assessed the potential for confounding engineering and/or catching effects due to different knot (‘sheet bend’) orientations (and therefore positive or negative hydrodynamic lift) in the principal horizontal panels of a penaeid trawl. During 24 paired comparisons, orientating all meshes in the top and bottom belly panels of a trawl to produce a negative angle of attack (AOA) for all knots resulted in greater wing-end spread, and lower catches of school prawns, Metapenaeus macleayi per hectre trawled (means reduced by up to 26%) and three key species of schooling fish (by up to 67%), but more debris (4×) than when the meshes were orientated to produce a positive AOA. By comparison, catches of two other benthic fish remained unaffected by knot orientation. These catch differences were attributed to the negative-AOA trawl potentially assuming a considerably lower position in the water column (and species-specific orientations). The results demonstrate that it is essential to maintain consistency in knot orientation in penaeid trawls when testing gear modifications and/or during fishery-dependent or -independent surveys.

Increasing lateral mesh openings in penaeid trawls to improve selection and reduce drag

In an attempt to improve selection and engineering efficiency in an Australian penaeid fishery, the mesh size and side taper of a generic trawl design were reduced (from 41 to 35mm) and increased (from 1N3B to 1N5B), respectively and, within the revised design, the independent and combined utility of (i) increasing the frame-line hanging ratio, and (ii) replacing the diamond-orientated wing/side panel with square-orientated mesh were investigated. Compared to the 41-mm mesh conventional trawl, all of four smaller-meshed designs (comprising either loose or tight hanging ratios, and with diamond- or square-mesh wing/side panels) had lower drag (9–12%) and required less fuel (up to 4–12%). Some of the small-meshed trawls caught fewer unwanted fish—attributed to the steeper side panels allowing individuals to swim forward and escape. Within the small-mesh trawls, there were incremental improvements in size selectivity for the targeted school prawns, Metapenaeus macleayi associated with both modifications. But the square-mesh wing/side panels were by far the most effective, reducing the catches of sub-commercial school prawns by up to 72%. The results support simple, retrospectively fitted alterations to existing penaeid-trawl bodies to improve selection and efficiency.

Effects of bycatch reduction devices in Queensland's (Australia) deepwater eastern king prawn (Melicertus plebejus) trawl fishery

This paper quantifies the effects of a square mesh codend bycatch reduction device (BRD) and turtle excluder device (TED) in the deepwater eastern king prawn (Melicertus plebejus) fishery on the southeast Queensland coast, based upon on a 10-day research charter. The bycatch comprised 224 taxa, mainly gurnards, flatheads, sandpaper fish, hermit and charybdid crabs, mantis shrimps, sand dollars (i.e. sea urchins), dragonets, snipefish, carids and lizardfish. The total mean bycatch rate was comparatively low (1114.0gha−1 from the standard diamond mesh codend), mainly because of the relatively deep waters associated with the fishery. When the TED and square mesh codend BRD were used together the total mean bycatch rate was significantly reduced by 29% (796.0gha−1) compared to the standard codend, with no significant effect on the prawn catch rate or size frequency distribution. Several bycatch species experienced very large reductions in mean catch rate, due to the square mesh codend, including Graham's conger Gnathophis grahamii (98.2% reduction), dumpling squid Euprymna tasmanica (95.9%), shortsnout threadsail Aulopus curtirostris (90.6%) and sandpaper fish Aulotrachichthys sp. (90.0%). Multidimensional scaling indicated that bycatch assemblages were more affected by latitude and depth than codend type. Based on the results, we recommend that the 47.6mm square mesh codend be made mandatory in the deepwater eastern king prawn fishery as a highly effective BRD.

Environmental and fishing effects on the dynamics of brown tiger prawn (Penaeus esculentus) in Moreton Bay (Australia)

This analysis of the variations of brown tiger prawn (Penaeus esculentus) catch in Moreton Bay multispecies trawl fishery estimated catchability using a delay difference model. It integrated several factors responsible for variations in catchability: targeting of fishing effort, increasing fishing power and changing availability. An analysis of covariance was used to define fishing events targeted at brown tiger prawns. A general linear model estimated inter-annual variations of fishing power. Temperature-induced changes in prawn behaviour played an important role on the dynamics of this fishery. Maximum likelihood estimates of targeted catchability (4.09±0.42×10−4boat-day−1) were twice as large as non-targeted catchability (1.86±0.25×10−4boat-day−1). The causes of recent declines in fishing effort in this fishery were discussed.

Catch Fluctuation of Kuruma Prawn, Penaeus japonicus in Japan Relative to Ocean Climate Variability and a Stock Enhancement Program

The kuruma prawn, Penaeus japonicus is widely distributed in the Indo-West Pacific. The Japanese stock enhancement program, which produces and releases juvenile kuruma prawns into their natural habitat, started in 1964 and has expanded throughout Japan. The annual number of juveniles released ranged from approximately 240 to 300 million until the mid-1990s but then decreased steadily to approximately 105 million in 2008. National annual landings of kuruma prawns recovered to a record of 3,741 t in 1985 from 1,263 t in 1970 but then declined steadily to the historical minimum of 726 t in 2008. Thus, kuruma prawn catches have decreased dramatically despite the release of juveniles. The aim of this study is to analyze the catch fluctuation of kuruma prawns relative to ocean climate variability and the stock enhancement program. The effects of ocean climate on kuruma prawn stock sizes were evaluated by generalised additive models (GAMs). In the GAMs, catch-per-unit effort and catch data transformed to reduce the dependence of the amplitude of the catch fluctuation on the level of the catch were used as response variables, and three indices for ocean current conditions were used as explanatory variables: the Oyashio (cold current), the Kuroshio (warm current), and the Tsushima Warm Current. The GAM analysis suggested that kuruma prawn stock sizes declined during the period with a strong warm current intensity, and 42 mark-recapture surveys indicated an estimated average yield per release of 0.9 g. Our analysis highlights the fluctuation of kuruma prawn stocks with ocean climate variability and indicates that the stock enhancement program could have an impact on kuruma prawn catches depending on the magnitude of the releases. Ocean climate change, decreased fishing effort, and reduced hatchery releases could be responsible for the recent decline in kuruma prawn catches in Japanese waters.

Relinkage of the Mfolozi River to the St. Lucia estuarine system – urgent imperative for the long-term management of a Ramsar and World Heritage Site

The St. Lucia Estuary was separated from the Mfolozi River in the early 1950s following canalisation of the Mfolozi floodplain swamp that resulted in the deposition of large amounts of sediment in the estuary. A separate Mfolozi River mouth has been maintained artificially since then and the deleterious consequences in terms of freshwater supply to the St. Lucia system are now becoming fully apparent, especially following the latest drought. Fish and penaeid prawn stocks in Lake St. Lucia have collapsed and the loss of this major southern African estuarine nursery area for these faunal components has had a significant impact on fish and prawn catches in adjacent coastal waters. It is therefore imperative that a re-linkage of the Mfolozi River to the St. Lucia system occurs so that the health and conservation status of the St. Lucia ecosystem, which is a Ramsar and World Heritage Site, can be assured. This review of the major findings presented at a recent scientific workshop explores the need for, and consequences of, a reconnection between the Mfolozi River and St. Lucia Estuary and makes some preliminary suggestions towards the achievement of that goal. Foremost amongst these proposals is to use the subsiding Mfolozi floodplain as a sink for excess sediment carried by the Mfolozi River before it enters the St. Lucia system, as well as various strategies in terms of reconnection options.