Abrupt environmental shift associated with changes in the distribution of Cape anchovyEngraulis encrasicolusspawners in the southern Benguela

Roy, Claude; Lingen, CD van der; Coetzee, Janet C.; Lütjeharms, J. R. E.

doi:10.2989/ajms.2007.29.3.1.331

Cited by 147 publications

(137 citation statements)

References 23 publications

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“…1) during 1984-1995 to being located predominantly to the east of Cape Agulhas from 1996 through 2010. Synchronous changes in temperature gradients across the Agulhas Bank suggested that this shift was environmentally mediated (Roy et al 2007). Sardines have also shown an eastward shift in their relative distribution, albeit a more gradual one.…”

Section: Jellyfishes In the Benguelamentioning

confidence: 99%

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Roux¹,

Lingen²,

Gibbons³

et al. 2013

BMS

128

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Changes in two contrasting ecosystems of the Benguela upwelling region, one dominated at mid-trophic level by jellyfishes (Namibia, northern Benguela ecosystem, where small pelagic fish abundance has been severely depleted) and one still dominated by small pelagic fishes (South Africa, southern Benguela) were compared in an effort to determine ecosystem trajectories under different exploitation regimes. The role of small pelagic fishes (clupeoids) was highlighted in the context of their importance in maintaining interactions in marine ecosystems. In particular, we examined trophic cascades and possible irreversible changes that promote the proliferation of jellyfishes in marine systems. We found that the presence of large populations of small pelagic fishes has a fundamental role in preserving beneficial trophic interactions in these marine ecosystems. The implications of trophic cascades, such as those observed in the northern Benguela, for ecosystem-based management were apparent. In addition, this comparison provides contrasting case studies to inform the development of management scenarios that avoid ecosystem shifts that affect predators and reduce the value of fisheries production.

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Section: Jellyfishes In the Benguelamentioning

confidence: 99%

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Roux¹,

Lingen²,

Gibbons³

et al. 2013

BMS

128

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“…Cury and Roy, 1989;Borja et al, 1998;Roy et al, 2007). Survey data indicate that European sardine (Sardina pilchardus) and European anchovy (Engraulis encrasicolus) dramatically increased in the southern North Sea in the mid-1990s (Beare et al, 2004) and the first evidence of spawning activity of sardine and anchovy in the North Sea was detected during the cruises made in [2003][2004] as part of the German GLOBEC programme (J.…”

Section: Introductionmentioning

confidence: 99%

Co-occurrence of European sardine (Sardina pilchardus), anchovy (Engraulis encrasicolus) and sprat (Sprattus sprattus) larvae in southern North Sea habitats: Abundance, distribution and biochemical-based condition

Kanstinger

2009

Sci. Mar.

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SUMMARY: Spawning populations of European sardines (Sardina pilchardus) and anchovies (Engraulis encrasicolus)have become re-established in the southern North Sea after a ~30-year absence and now co-occur with sprat (Sprattus sprattus). Consequently, little is known concerning potential interactions among these three species in this region. Based upon parallel cruises conducted in June/July 2005, we compared the larval abundance, size-distributions and biochemical-based condition of these species among 1) nearshore (Wadden Sea) areas and offshore (German Bight) areas that were 2) vertically mixed, 3) frontal zones, or 4) stratified waters. In general terms, larval condition (RNA:DNA) was relatively high at all stations. Although fronts clearly acted to concentrate larvae, larval condition was not necessarily higher. For example 9% of sardines captured at the tidal mixing front were categorised as starving, while no starving larvae were sampled in the stratified water masses. Habitats of sardine and sprat larvae were similar, whereas anchovies were primarily restricted to nearshore areas. This is the first study examining the potential role of near-and offshore habitats as nursery areas and the extent to which resource (habitat) partitioning exists among the larvae of sprat and newly established anchovy and sardine in the North Sea.Keywords: clupeiform fish, larvae, habitats, RNA:DNA, growth. RESUMEN: CO-APARICIÓN DE LAS LARVAS DE SARDINA EUROPEA (SARDINA PILCHARDUS), ANCHOA (ENGRAULIS ENCRASICOLUS) Y ES-PADÍN (SPRATTUS SPRATTUS) EN HÁBITATS DEL SUR DEL MAR DEL NORTE:ABUNDANCIA, DISTRIBUCIÓN Y CONDICIÓN BIOQUÍMICA. -La puesta de la sardina (Sardina pilchardus) y de la anchoa (Engraulis encarsicolus) se han restablecido en el sur del mar del Norte después de casi 30 años de ausencia, apareciendo ahora juntamente con el espadín (Spattus sprattus). Consecuentemente, poco se conoce de las interacciones entre estas tres especies en esta región. Se ha llevado a cabo dos campañas entre Junio y Julio 2005, comparando la abundancia larvaria, distribución de tallas y la relación ARN:ADN de estas tres especies de clupeidos entre: 1) zonas costeras (Mar Wadden) y mar abierto (Bahía Alemana), 2) mezcla vertical, 3) zonas frontales y 4) masas de aguas estratificadas. En términos generales, la condición larvaria (relación ARN:ADN) fue relativamente alta en todas las estaciones. Aunque las zonas frontales actúan claramente como concentradoras de larvas, la condición larvaria no fue necesariamente más alta allí. Por ejemplo, el 9% de las larvas de sardinas capturadas en la zona de mezcla de marea fue clasificada en estado de inanición, mientras que las larvas de sardinas en estado de no inanición fueron capturadas en zonas de masas de aguas estratificadas. El hábitat de las larvas de sardina y de las larvas de espadín fueron más similares entre sí, mientras que las larvas de anchoas fueron encontradas en zonas costeras. Este estudio es el primero en investigar la importancia del hábitat de estas especies en zonas costeras y mar a...

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“…These results were confirmed by Blamey et al (2012), who further refined the analyses of Howard et al (2007) and Roy et al (2007) to indicate increased variability of upwelling at the west coast since 1996 (a situation detrimental to sardine), and increased upwelling (i.e., productivity) at the south coast in the period 1996-2003, in line with increased availability and recruitment of small pelagics along the south coast.…”

Section: Environmental Regime Shiftsmentioning

confidence: 67%

Long-term, Ecosystem-Scale Changes in the Southern Benguela Marine Pelagic Social-Ecological System: Interaction of Natural and Human Drivers

Jarre¹,

Ragaller²,

Hutchings³

2013

E&S

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-scale changes in the southern Benguela marine pelagic social-ecological system: interaction of natural and human drivers. Ecology and Society18(4) ABSTRACT. South Africa's small pelagics fishery is currently the largest in volume and second largest in value in the southern Benguela. It exploits short-lived, small pelagic fishes such as anchovy (for reduction into fish meal and oil) and sardine (for reduction as well as human consumption through canned products), and to a lesser extent redeye round herring and mesopelagics, largely for reduction. We explore the recent history (1940s to present) of the social-ecological system around this fishery. The natural subsystem, at the scales of the ocean environment and the ecosystem, is characterized by high interannual and documented decadal-scale variability. We characterize the human social subsystem at the scales of the fishing industry, legislation, and west coast fishing towns, and demonstrate interdependencies between the natural and social subsystems by following system-scale changes. The pelagic fishing industry has evolved to deal with variability through consolidation, diversification, and range expansion. Legislation has increasingly looked for conservation of the resource while ensuring economic viability of the industry, and hence factory-and vessel-related jobs. Fishing communities under apartheid stayed largely dependent on company-generated infrastructure, combining seasonal employment in the fishing factories with inshore fishing, targeting rock lobster and line fish. While the pelagic industry persisted and communities survived, the resource base for both offshore and inshore fisheries gradually eroded. The advent of democracy in the mid-1990s brought allocation of long-term fishing rights to individuals or companies under conditions of depleted inshore resources aggravated by a shift in the distribution of pelagic fish away from the west coast towards the Cape south coast in the second half of the 1990s. The resultant loss of employment and fishing rights in the inshore has generated community coping strategies that include poaching and challenges to the current Marine Living Resources Act, while the industry continues to expand by range and species, possibly further eroding the resource base. We argue that the situation in the pelagic social-ecological system is indicative of further loss of resilience to change. Coping with future longterm, system-scale change will necessitate careful long-term scenario planning among the various interest groups involved, joint research being one way to overcome the communications breakdown and initiate the joint planning process.

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Abrupt environmental shift associated with changes in the distribution of Cape anchovyEngraulis encrasicolusspawners in the southern Benguela

Cited by 147 publications

References 23 publications

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Jellyfication of Marine Ecosystems as a Likely Consequence of Overfishing Small Pelagic Fishes: Lessons from the Benguela

Co-occurrence of European sardine (<i>Sardina pilchardus</i>), anchovy (<i>Engraulis encrasicolus</i>) and sprat (<i>Sprattus sprattus</i>) larvae in southern North Sea habitats: Abundance, distribution and biochemical-based condition

Long-term, Ecosystem-Scale Changes in the Southern Benguela Marine Pelagic Social-Ecological System: Interaction of Natural and Human Drivers

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