Zooplankton Communities in the West African Upwelling Area

Thiriot, Alain

doi:10.1007/978-3-642-66985-9_5

Cited by 26 publications

(13 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Fledglings would be unable to catch any of the prey species, suggesting that fledglings have different foods from adults. Most of the slow-moving macrozooplankton in the region (Thiriot 1978) are too small or live too deep (e.g. Talbot 1974) to constitute Jackass Penguin prey.…”

Section: Maximum Speed and Prey Availabilitymentioning

confidence: 99%

The Jackass Penguin (Spheniscus demersus) as a pelagic predator

Wilson¹

1985

Mar. Ecol. Prog. Ser.

105

View full text Add to dashboard Cite

Swimming and diving capabilities of Jackass Penguin Spheniscus demersus were examined. Mean maximum speed over a 10 m course in a rock pool was 12.4 km h-' for breeders, 9.5 km h-' for juveniles and 4.6 km h-' for fledglings. Theoretically fledglings could not swim fast enough to catch adult Cape Anchovies Engraulis capensis, the normal prey of adults. Fledglings probably feed on fish larvae. Moulting penguins swam at speeds comparable to fledglings and did not feed. When travelling to the foraging area, breeding penguins swam at 4.8 km h-'. Maximum theoretical foraging range is 24.2 km, but actual range was < 20 km. Mean duration of dive was 22.3 S inside Saldanha Bay and 146 S outside the bay. During long dives outside Saldanha Bay, penguins were probably foraging. At midday, when most Jackass Penguins are at sea, largest numbers were seen outside the bay in 30 to 40 m depth. Penguins fitted with depth gauges dived routinely to 30 m, but spent most time in the upper water layers. Maximum recorded depth was 130 m. There was a positive correlation between distance swum and amount of food ingested. This suggests that the anchovy on which they feed formed small schools which were encountered frequently.

show abstract

Section: Maximum Speed and Prey Availabilitymentioning

confidence: 99%

The Jackass Penguin (Spheniscus demersus) as a pelagic predator

Wilson¹

1985

Mar. Ecol. Prog. Ser.

105

View full text Add to dashboard Cite

show abstract

“…The continental margins of the oceans are usually characterized by intense spatial variability of the plankton community (Mackas et al 1985) and dense concentrations of euphausiids are frequently observed at or just beyond the shelf break (Pearcy 1976, Thiriot 1978, Simard et al 1986). Although in coastal upwelling regions euphausiid biomasses are higher in inshore areas (Smiles & Pearcy 1971, Pillar & Stuart 1988, Barange & Stuart 1991, an increase in the biomass and diversity of the euphausiid community is usually observed near the shelf break (Pillar & Stuart 1988, Barange & Stuart 1991.…”

Section: Introductionmentioning

confidence: 99%

Diet and feeding of Euphausia hanseni and Nematoscelis megalops (Euphausiacea) in the northern Benguela Current: ecological significance of vertical space partitioning

Barangé¹,

Gibbons²,

Carola³

1991

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Patterns of diel migration and feeding of Euphausia hanseni and Nernatoscelis rnegalops were investigated in waters of the northern Benguela (Namibia) upwelling system. N. megalops migrated to just below the thermocline at night and fed maximally in the early evening E. hanseni migrated to above the thermocline at night and fed progressively throughout the night. Although both species were omnivorous and consumed similar size ranges of copepod prey, differential prey sizefrequency with depth resulted in E. hanseni consuming mostly small-sized copepods and N. megalops preferring m e d u m size classes. At depths of overlap the 2 species appeared to partition copepod food resources on the basis of size. Verhcal spatial partitioning is examined in light of temporal and dietary separation, and overlapping horizontal distribution patterns of the species in the northern Benguela upwelling system. It is concluded that vertical space partitioning is a reflection of the structure of shelf break zooplankton communities, which is a strategy of sharing highly productive areas and avoiding competition.

show abstract

“…This seasonal cycle of the zooplankton activity along the Moroccan coast is related to the upwelling cycle which develops in spring, is reinforced in summer, attenuates in autumn and decreases in winter (Furnestin, 1959;Thiriot, 1978;Belvèze, 1991;Orbi & Nemmaoui, 1992 ). Thus, the zooplankton activity in M'Diq can be related to the seasonal cycle of the Mediterranean water mass which follows change of flow entering and outgoing through the Gibraltar Strait (Larnicol et al, 1995;Traon et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

A comparative study of marine zooplankton communities in the Tangier and M’Diq (Gibraltar strait) regions

Zaafa¹,

Ettahiri

Berraho

et al. 2012

Hydroécol. Appl.

View full text Add to dashboard Cite

-This comparative study of mesozooplankton communities in the Tangier (Atlantic) and M'Diq (Mediterranean) regions was carried out in March, May and December 2006 and in May, July and November 2007. In both sectors, the zooplankton is mainly dominated by copepods, which represent 93% in Tangier and 87% in M'Diq, with respectively 85 species in 24 families and 81 divided into 22 families. Spatio-temporal analysis of Copepod specific richness data revealed highest values occurring in both areas during December 2006 and November 2007 with 36 and 30 species respectively. During other seasons, specific richness did not generally exceed 25 species. However, irrespective of area, the composition of the Copepoda population was usually dominated by Paracalanus parvus and Oncaea venusta. In terms of total density, the Atlantic is greater than the Mediterranean sector with a maximum density of 1093 ind.m −3 and 796 ind.m −3 , respectively, recorded in July and May, 2007. The Shannon diversity index was calculated and indicated that the Copepod community is more stable and balanced in the Tangier region compared to the M'Diq area, and in 2007 compared to 2006. Moreover, seasonal variation is more marked in the Atlantic than in the Mediterranean area and in both sectors, the autumn season is characterized by a low productivity but high specific diversity. Key words

show abstract

Zooplankton Communities in the West African Upwelling Area

Cited by 26 publications

References 58 publications

The Jackass Penguin (Spheniscus demersus) as a pelagic predator

The Jackass Penguin (Spheniscus demersus) as a pelagic predator

Diet and feeding of Euphausia hanseni and Nematoscelis megalops (Euphausiacea) in the northern Benguela Current: ecological significance of vertical space partitioning

A comparative study of marine zooplankton communities in the Tangier and M’Diq (Gibraltar strait) regions

Contact Info

Product

Resources

About