Law and fisheries reform: Legislative and policy developments in South African fisheries over the decade 1994–2004

Following the enactment of the Constitution in 1996, the South African government undertook a process of legal reform in the fishing sector. This led to the publication of a new fisheries policy endorsing equity and sustainability, as reflected in the Marine Living Resources Act. This paper examines efforts to implement the policy, particularly the objective of “transformation”, against the background of law reform in fisheries over the last decade. The discussion is located within the context of related domestic legal developments and current trends in international fisheries law. Methods for enhancing effective implementation of the new fisheries policy are highlighted.     

Effects of mining wastes on a seagrass ecosystem: metal accumulation and bioavailability, seagrass dynamics and associated community structure

Two different Cymodocea nodosa (Ucria) Ascherson beds growing in mining-contaminated sediments were compared with two reference beds in the Mar Menor coastal lagoon. The accumulation of Zn, Pb and Cd in different fractions of the plant, the sediment parameters that regulate the availability of metals, the seabed structure and dynamics of each seagrass bed and its associated macroinvertebrate community were studied. C. nodosa accumulates metals from the sediments and reflects their bioavailability for this seagrass. At each station, the metal content of the rhizomes was lower than that of leaves and roots. The concentration of acid-volatile sulfides does not seem to influence the availability of metals to the seagrass, possibly due to oxygen transport to underground tissues. The highest metal concentration in all the contaminated stations was found in the leaf-biofilm, due to the formation of complexes between metals and the extracellular polymeric substances that form the biofilm. All the seagrass beds were seen to be undergoing expansion, those growing in contaminated sediments accumulating great quantities of metals and showing highest photosynthetic leaf surface area and highest leaf biomass. However, these structural parameters were not seen to be responsible for the differences in the faunal composition observed between contaminated and reference beds. Moreover, the multivariate analysis identified the metal content of leaves, biofilm and sediments as important variables that may be responsible for these differences in faunal composition. In this study we have demonstrated that both the seagrass C. nodosa and the biofilm on the plant leaves may be used as environmental tools in the Mar Menor lagoon. The former is an useful indicator of sediment contamination, whereas the latter seems to be a good sentinel of water quality.     

Seagrass landscapes and their effects on associated fauna: A review

Seagrasses comprise some of the most heterogeneous landscape structures of shallow-water estuarine/marine ecosystems in the world. However, while knowledge at the molecular, organism, patch and community scale is pervasive, understanding of seagrass landscape ecology is more fragmentary and has not been synthesized. The growth and recruitment dynamics of seagrasses as well as man-made and/or natural disturbances create complex spatial configurations of seagrass over broad (metres to kilometres) spatial scales. Hence, it is important to identify mechanisms maintaining and/or threatening the diversity-promoting function of seagrass meadows and to understand their effects on benthic populations and communities. Although landscape ecology has recently become more integrated into seagrass research, our understanding of animal responses to variability in seagrass landscape structure is still fragmentary. By reviewing the literature to date, this paper evaluates studies on seagrass landscape ecology, testing the general null hypothesis that concepts developed in terrestrial settings can be generalized across landscapes, and (a) presenting definitions and terms used in seagrass landscape ecology, (b) reviewing geographical patterns of seagrass landscape studies to identify possible key regions and target species, (c) evaluating different methodological approaches, (d) describing the spatial and temporal scales used to describe organism responses to seagrass landscape structure, and (e) placing seagrass landscapes into an applied context.     

Seasonal dynamics of ciliated protozoa and their potential food in an eutrophic estuary (Bay of Biscay)

Ciliate assemblages, together with phytoplankton and heterotrophic nanoflagellates (HNF) as their potential food, have been surveyed monthly along the salinity gradient of the Nervión River estuary from March 2000 to March 2002. A total of 135 taxa of ciliate have been identified corresponding to 20 orders. Scuticociliates, naked choreotrichs and oligotrichs were the most abundant groups, distributed throughout a broad range of salinity. In addition to these groups, which were the dominant taxa in the middle estuary, tintinnids were characteristic of the ciliate assemblages of the outer estuary whereas in the innermost part naked choreotrichs and oligotrichs decreased in number, being substituted by sessilids, hymenostomatids, peniculids and cyrtophorids. Total ciliate concentrations were among the highest reported in the literature for other estuaries and coastal waters, frequently reaching 10⁵ cells l⁻¹. Meanwhile, tintinnid concentrations were comparable with those of other estuarine and coastal waters. Based on a principal component analysis (PCA) three main groups were delineated, with ciliates and their potential food sources as variables. One was that constituted by freshwater ciliate such as sessilids, hymenostomatids, cyrtophorids and pleurostomatids, which appear in low numbers in the innermost part, mainly in winter. Another group contained diatoms, chlorophytes, flagellates, euplotids and scuticociliates, all of them broadly distributed along the estuary and reaching their maximum density in late spring–summer. The third group was made up of taxa mainly appearing at the seaward end such as dinoflagellates, cyanobacteria, haptorids, tintinnids, naked choreotrichs and oligotrichs, which reached the highest densities in summer and early autumn. Ciliates do not seem to be food limited in the Nervión River estuary or much controlled by metazoan grazing.     

Mussel fouling on the Celtic Sea Kinsale Field gas platforms

Fouling was investigated on Marathon Kinsale Field Alpha and Bravo platforms in the Celtic Sea between June 1978 and June 1981. In shallow depths, algae dominated, chiefly Polysiphonia brodiaei and Ulva lactuca. Mussels formed the dominant fouling organism between 6 and 20 m depth, below which were zones of Metridium senile and Alcyonium digitatum, serpulids and the deep water barnacle Balanus hameri. In September 1979 mussels exceeded 2500 m⁻² with a modal length of 42 mm. By June 1981, modal length had increased to 67 mm at −4 m and 73 mm at −18 m (maximum size 97 mm). Populations on Bravo were similar. Comparison is made with growth rates on North Sea platforms. On Alpha, percentage cover m⁻² in March 1980 was much greater at −4 m than at −18 m, but mean thickness was similar. At −18 m mussels were a heavier fouler on Bravo than Alpha. On Alpha mussel weight did not show a linear relationship with percentage cover.     

Tropical forests: Present status and future outlook

Tropical forests still cover almost 8 million km² of the humid tropics. But they are being destroyed at ever-more rapid rates. In 1989 the area deforested amounted to 142 200 km², or nearly 90% more than in 1979. So whereas the 1989 total amounted to 1.8% of the remaining biome, the proportion could well continue to rise for the foreseeable future, until there is little forest left in just another few decades.Deforestation patterns are far from even throughout the biome. In much if not most of Southeast and Southern Asia, East and West Africa, and Central America, there is likely to be little forest left by the year 2000 or shortly thereafter. But in the Zaire basin, western Brazilian Amazonia and the Guyana highlands, sizeable expanses of forest could persist a good while longer.The main agent of deforestation is the shifted cultivator or displaced peasant, who, responding to land hunger and general lack of rural development in traditional farming areas of countries concerned, feels there is no alternative but to adopt a slash-and-burn lifestyle in forestlands. This person is now accounting for at least 60% of deforestation, a proportion that is expanding rapidly. Yet he receives far less policy attention than the commercial logger, the cattle rancher and other agents of deforestation.This is a summary review of a report Deforestation Rates in Tropical Forests and Their Climatic Implications, prepared by the author and Richard A. Houghton for Friends of the Earth U.K. (available from 26–28 Underwood St., London N1 7JQ). A similar review, albeit with less updating than is included here, has been published by Myers, 1990a. The original report, being five times longer than the present paper, contains much detail of deforestation assessments on a country-by-country basis, backed by 400 references. It also presents information on research methodologies and reliability of data among other background materials, plus an analysis of carbon emissions from deforestation, as well as some policy appraisal and conservation recommendations.