Status of the major lobster fisheries in India

Commercial exploitation of lobsters from the Indian seas began in the 1950s. Annual landings have been declining from a peak of 4075 t in 1985 to 1364 t in 2002. Major fisheries were located on the north‐west, south‐west, and south‐east coasts. Among the 12 species recorded, only four species of spiny lobsters (three littoral and one deep sea) and one species of slipper lobster are commercially important. At Kayalpattinam and Tharuvaikulam, on the south‐east coast, lobster landings sharply declined for the gill‐net fishery. Of the two species that contributed to the fishery, Panulirus ornatus and Panulirus homarus, the latter has been more affected owing to high vulnerability to fishing activities. Catch composition analysis of the trammel‐net fishery showed that 35% of the landings consisted of P. homarus in the size range of 23–50 mm carapace length. On the north‐west coast, the spiny lobster Panulirus polyphagus and the slipper lobster Thenus orientalis are incidentally caught in trawl nets. However, the fishery for T. orientalis in the waters off Mumbai lasted only up to 1994. Large‐scale exploitation of spawning females, which formed 60% of the total catch, might have been detrimental to the recruitment process resulting in rapid decline and total collapse of the fishery. Abundance of P. polyphagus reached its maximum during September, constituting 23% of the average annual landing during 1988–2002. A high exploitation ratio (>0.7) indicated over‐fishing of the stock. Repeated spawning and high annual egg production are probably responsible for sustaining the stock, despite over‐exploitation. Major problems confronting the resource management of the multi‐gear and multi‐species lobster fisheries in India are discussed. An operational project, involving fisher community, has been taken up for creating awareness of the need for sustainable exploitation of the resource. Regulatory measures, such as closure of the fishery during the peak of the breeding season, ban on trammel‐net, mandatory release of egg‐bearing lobsters, and establishment of lobster sanctuaries are suggested to the State Governments for implementation.     

The 2004 re-assessment of the South African sardine and anchovy populations to take account of revisions to earlier data and recent record abundances

Hydroacoustic surveys off the coast of South Africa over the early years of the 21st century indicated that both the sardine Sardinops sagax and anchovy Engraulis encrasicolus populations had simultaneously reached record abundances. The South African pelagic fishery is regulated using an Operational Management Procedure (OMP). The OMP in use at that time had been developed using data from the two populations prior to this rapid and substantial increase in abundances. This paper documents the revised assessments that were urgently required to provide a basis to update the OMP. These assessments resulted in a changed perception of the status and productivity of these populations. In particular, estimates of the stock-recruitment relationships and the extent of variation about them, which play a key role in evaluating risk when developing OMPs, altered substantially from estimates derived from earlier assessments.     

A cautious fisheries management policy in South Africa: the fisheries for rock lobster

In South Africa, political emancipation has resulted in a new fisheries policy which is embodied in the Marine Living Resources Act of 1998. The pillars of the new policy are sustainability, equity and stability within the industry. We look particularly at a suite of mainly accessible species, the rock lobsters (truly spiny lobsters), at their management, at control measures, at realities of resource status and harvesting, at naturally occurring ecosystem stimuli, and investigate whether the policy can achieve what it aims to do, to provide more for more South Africans at levels at least equal to what they do today. Put simply, are the political aims and the sustainability aims of the new policy mutually achievable?     

A spatial- and age-structured assessment model to estimate the impact of illegal fishing and ecosystem change on the South African abalone Haliotis midae resource

The management of abalone stocks worldwide is complicated by factors such as illegal fishing combined with the difficulties of assessing a sedentary (but not immobile) resource that is often patchily distributed. The South African abalone Haliotis midae fishery is faced with an additional problem in the form of a relatively recent movement of rock lobsters Jasus lalandii into much of the range of the abalone. The lobsters have heavily reduced sea urchin Parechinus angulosus populations, thereby indirectly negatively impacting juvenile abalone which rely on the urchins for shelter. A model is developed for abalone that is an extension of more standard age-structured assessment models because it explicitly takes spatial effects into account, incorporates the ecosystem change effect described above and estimates the magnitude of substantial illegal (‘poached’) catches. The model is simultaneously fitted to catch per unit effort and Fishery-Independent Abalone Survey abundance data, as well as to several years of catch-at-age (cohort-sliced from catch-at-size) data for the various components of the fishery and different spatial strata. It constitutes the first quantitative approach applied to the management of this commercially valuable resource in South Africa and has provided a basis for management advice over recent years by projecting abundance trends under alternative future catch levels.     

Monitoring the recovery of a previously exploited surf-zone fish community in the St Lucia Marine Reserve,South Africa,using a no-take sanctuary area as a benchmark

Limiting accessibility to a fishing area can reduce fishing effort effectively and may therefore promote local recovery of depleted stocks. In January 2002, beach driving was banned in South Africa, thereby reducing angler access to large areas of the coastline, particularly in less-developed areas. In November 2001 a project had been established in the St Lucia Marine Reserve, on the east coast of South Africa, to compare surf-zone fish populations inside a no-take sanctuary zone with those in an adjacent exploited area. Subsequent to the ban, the aim of the project was adapted such that surf-zone fish populations were monitored for potential recovery in what had been the exploited area, located to the north of Cape Vidal, which anglers could no longer access easily, because of the prohibition on beach driving. Standardised research fishing was conducted at two sites in the previously exploited area and two sites in the no-take sanctuary. Conventional stock-status indicators showed evidence of recovery in the four most common species caught in the previously exploited area, in terms of both abundance and biomass. Generalised additive mixed models were used to account for the influence of targeting specific species; however, subtle differences in habitat between the sampling sites, improved angling skill over time, variability in recruitment, and differential species-specific responses complicated interpretation of results. The implications of the findings are discussed in terms of the future monitoring and management of marine protected areas both within the St Lucia Marine Reserve and farther afield.     

A review of the ecology and management of temporarily open/closed estuaries in South Africa,with particular emphasis on river flow and mouth state as primary drivers of these systems

Research in South African temporarily open/closed estuaries that includes studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fishes and birds is used as a basis to review the ecology and management of this estuary type on the subcontinent. Particular attention is given to the responses of the different ecosystem components to the opening and closing of the estuary mouth and how this is driven by riverine and marine events, as well as anthropogenic influences. In addition, the wider implications of these research findings for the management of temporarily open/closed estuaries in terms of freshwater supply are explored, together with the role of government legislation in maintaining the ecological integrity of these important wetland systems.