Annual and interannual variability in the South-East Atlantic during the 20th century

Taunton-Clark, J.; Shannon, L. V.

doi:10.2989/025776188784480654

Cited by 31 publications

(21 citation statements)

References 8 publications

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“…The 1980s brought a rapid increase in knowledge and understanding of processes in the Benguela ecosystem, stimulated by the multi-and interdisciplinary Benguela Ecology Programme (Siegfried and Field 1981, Payne et al 1987, Shannon et al 1988. The programme fostered close cooperation between researchers in the public sector and those at universities, museums and the Council for Scientific and Industrial Research (CSIR).…”

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confidence: 98%

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The 1980s – a decade of change in the Benguela ecosystem

Shannon¹,

Crawford²,

Pollock³

et al. 1992

South African Journal of Marine Science

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Changes that occurred in sea surface and some deeper temperatures, surface winds, currents, plankton and some dominant crustacean (rock lobster Jasus lalandii), molluscan (squid Loligo vulgaris reynaudii and abalone Haliotis midae), fish (anchovy Engraulis capensis, pilchard Sardinops oce/latus, Cape hakes Merluccius spp., sole Austroglossus pectoralis, kingklip Genypterus capensis and various species of linefish) and seabird (Cape gannet Morus capensis) resources in the Benguela ecosystem in the 1980s are documented. Although fishing had a clear influence on changes in some of the resources, a wide spectrum of organisms, from plankton to top predators, were influenced directly or indirectly by the abiotic environment. Concurrent changes in many of the resources suggest that the same environmental change may impact on more than one. Simultaneous change throughout the Benguela system indicates that environmental forcing sometimes takes place over wide geographic areas. At the northern and southern extremities of the Benguela system, responses to environmental change may be different because processes through which the change is mediated are different.Verandering wat plaasgevind het in die see-oppervlak-en sommige dieper temperature, oppervlakwinde, strome, plankton en sommige hulpbronne soos skaaldiere (kreef Jasus lalandii), weekdiere (tjokka Loligo vulgaris reynaudii en perlemoen Ha/iotis midae), vis (ansjovis Engraulis capensis, sardyn Sardinops oce/latus, Kaapse stokvis Merluccius spp., tongvis Austroglossus pectoralis, koningklip Genypterus capensis en verskeie lynvisspesies) en seevoels (witmalgas Morus capensis) in die Benguela-ekostelsel in die 1980s word gedokumenteer. Ofskoon die vissery 'n duidelike invloed op veranderinge in somrnige van die hulpbronne gehad het, is 'n wye spektrum organismes, van plankton tot spitsroofdiere, regstreeks of onregstreeks be"invloed deur die nie-Iewende omgewing. Gelyktydige veranderinge in baie van die hulpbronne dui daarop dat dieselfde omgewingsverandering op meer as een van hlllle 'n uitwerking mag he. Gelyktydige verandering dwarsdeur die Benguelastelsel laat dink dat omgewingsforsering soms oor wye geografiese gebiede plaasvind. By die noorder-en suider-uiteindes van die Bengllelastelsel kan die reaksies op omgewingsverandering verskil omdat die prosesse waardeur die verandering teweeggebring word, verskil. 1992 4 J 2 J

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confidence: 98%

“…Bergh and Butterworth 1987). Reliable time-series of biomass, 272 Benguela Trophic Functioning South African Journal of Marine Science 12 1992 Table I Numbering of the areas is kept the same as tor previous analyses reported by Taunton-Clark and Shannon (1988) and Shannon and Taunton-Clark (1989) Poleward…”

mentioning

confidence: 99%

The 1980s – a decade of change in the Benguela ecosystem

Shannon¹,

Crawford²,

Pollock³

et al. 1992

South African Journal of Marine Science

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“…In addition, several significant associations between large-scale features in the sea surface temperature described by Taunton-Clark and Shannon (1988) and various Benguela fish stocks were shown by Shannon et al (1992). Sharp and McLain (1993) attribute the alternating rise and fall of Pacific sardine and anchovy populations to long-term (40 year) changes in coastal temperatures and upwelling, in which EI NiflO events playa role but do not dominate.…”

Section: Discussionmentioning

confidence: 90%

“…The Western Cape, on the other hand, showed an upward trend (p < 0,01) during the middle period. In all instances, the trend over the 15-year period may possibly be ascribed to some inherent periodicity on a decadal scale, as described for sea surface temperature by Taunton-Clark and Shannon (1988). Such a pattern would be less important to the analysis of the whole time-series.…”

Section: Temporal Trends In Oil-to-meal Ratiosmentioning

confidence: 94%

Oil-to-meal ratios of pelagic fish taken from the northern and the southern Benguela systems: seasonal patterns and temporal trends, 1951–1993

Schülein¹,

Boyd²,

Underhill³

1995

South African Journal of Marine Science

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“…Climate records show that the equatorward wind stress has increased since 1950 (Taunton-Clark and Shannon 1988, Shannon et al 1992. Although the sea surface temperature in all areas showed a slight increase between 1920 and 1980, it is likely that the increased equatorward wind stress would have reduced the sea temperatures close inshore, where the effects of upwelling are manifest.…”

Section: Marine Ecosystem Changementioning

confidence: 96%

Collapse of linefish stocks between Cape Hangklip and Walker Bay, South Africa

Attwood¹,

Farquhar²

1999

South African Journal of Marine Science

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The state of the linefishery between Cape Hangk]ip and Walker Bay on the Cape south coast, South Africa, is assessed. The coast was subdivided into 20 "beats" to provide high spatial resolution on catch and effort of the shore-based recreational fishery. An observer recorded the number of anglers in each fishery sector, and their catch, during shore patrols over a two-year period. Catch-and-effort data for the commercial boat-based fishery were obtained from an historical database at the turn of last century and from the extant National Marine Linefish System database. Catch per unit effort (cpue) of shore-anglcrs was low and many of the species caught earlier in the century have disappeared from catches. Compared to the early records, contemporary commercial linefish cplle had dropped by approximately 80%, despite a greater fishing capacity. It is argued that most targeted stocks have been overexploited (notwithstanding indications of environmental change) and many are severely depleted. Poor management of the fishery, including a lack of control of commercial effolt and inadequate enforcement, contributed to overexploitation.

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Annual and interannual variability in the South-East Atlantic during the 20th century

Cited by 31 publications

References 8 publications

The 1980s – a decade of change in the Benguela ecosystem

The 1980s – a decade of change in the Benguela ecosystem

Oil-to-meal ratios of pelagic fish taken from the northern and the southern Benguela systems: seasonal patterns and temporal trends, 1951–1993

Collapse of linefish stocks between Cape Hangklip and Walker Bay, South Africa

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