Seasonal variation of oxygen deficiency in waters off southern South West Africa in 1975 and 1976 and its relation to the catchability and distribution of the Cape rock lobster<i>Jasus lalandii</i>

Bailey, G.W.; Beyers, Christiaan; Lipschitz, Steven Richard

doi:10.2989/025776185784461126

Cited by 34 publications

(21 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Seasonal changes in density, sex ratio and size distribution in other species of spiny lobster have been linked to variations in sea temperature (Davis 1977), dissolved oxygen levels (Netvman & Pollock 1971, Bailey et al 1985, storm events (Mercer 1975, Herrnkind 1980) and photoperiod (Kanciruk & Herrnkind 1973). In this study, sea surface temperature and photoperiod were weakly correlated to changes in densities of female spiny lobsters but this need not indicate a causal relationship.…”

Section: Discussionmentioning

confidence: 67%

See 1 more Smart Citation

Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jasus edwardsii on a coastal reef in northern New Zealand

MacDiarmid¹

1991

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

Patterns of abundance and movement of the spiny lobster Jasus edwardsii (Hutton) (F. Palinuridae) were examined within a coastal reef system. Overall population size remained relatively stable over a 3 yr study period. Marked differences in density, sex ratio and size frequency of spiny lobsters occurred between depths on the reef over a horizontal scale of 300 m. These differences varied seasonally and were related to moulting, reproductive and feeding cycles. They were not directly Linked to fluctuations in sea surface temperature, sea surge or photoperiod. Similar annual trends occurred at other sites. Highest densities of females in shallow (< 10 m) water coincided with moulting in May. Males moved inshore only briefly to moult in October-November often with no concomitant increase in male density in shallow (< 10 m) water. Increases in density of females at the deep (25 m) seaward edge of the coastal reef occurred during the egg-bearing period. In summer (December, January) the density of large males at a deep patch reef (25 to 30 m) increased. These males foraged nocturnally for bivalves on the surroundmg sand flat. Resighting of tagged individuals confirmed that the observed fluctuations in density, sex ratio and size frequency of spiny lobsters at different depths were caused by males and females moving inshore-offshore at different times of the year.

show abstract

Section: Discussionmentioning

confidence: 67%

“…This is because of latitudinal and size-dependent variations in the timing of moulting and reproduction (Street 1969, McKoy & Esterman 1981, Lipcius 1985, MacDiarmid 1989a, and differences in the depth range of suitable habitats (e.g. Bailey et al 1985) and major prey species (e.g. Newman & Pollock 1974).…”

Section: Discussionmentioning

confidence: 99%

Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jasus edwardsii on a coastal reef in northern New Zealand

MacDiarmid¹

1991

Mar. Ecol. Prog. Ser.

View full text Add to dashboard Cite

show abstract

“…in April-March 2001 an area of >20 000 km 2 in Namibia was affected for over two weeks (Weeks et al, 2002(Weeks et al, , 2004. These sulphidic eruptions are commonest in the Walvis BaySwakopmund area, causing considerable economic damage (Bailey et al, 1985). Milky discolouration in these cases is accompanied by substantial amounts of hydrogen sulphide and O 2 concentrations <0.2 ml O 2 l −1 in surface waters right up to the beach Weeks et al, 2002Weeks et al, , 2004.…”

Section: Nearshore Zone (Intertidal Uppermost Subtidal To 10 M)mentioning

confidence: 99%

“…in common whereas the species Panulirus gracilis stays outside cold upwelling water off Peru unless there is an EN (but the genus lives in the Galápagos Islands). Off Namibia, rock lobsters only occur until 15-30 m depth whereas off South Africa they are exploited to 55 m (Bailey et al, 1985). Squid (invertebrates but pelagic) are common fishery targets in all upwelling systems.…”

Section: Intermediate Zonementioning

confidence: 99%

El Niño and similar perturbation effects on the benthos of the Humboldt, California, and Benguela Current upwelling ecosystems

Gallardo²,

et al. 2006

View full text Add to dashboard Cite

Abstract. To a certain degree, Eastern Boundary Current (EBC) ecosystems are similar: Cold bottom water from moderate depths, rich in nutrients, is transported to the euphotic zone by a combination of trade winds, Coriolis force and Ekman transport. The resultant high primary production fuels a rich secondary production in the upper pelagic and nearshore zones, but where O 2 exchange is restricted, it creates oxygen minimum zones (OMZs) at shelf and upper slope (Humboldt and Benguela Current) or slope depths (California Current). These hypoxic zones host a specifically adapted, small macro-and meiofauna together with giant sulphur bacteria that use nitrate to oxydise H 2 S. In all EBC, small polychaetes, large nematodes and other opportunistic benthic species have adapted to the hypoxic conditions and co-exist with sulphur bacteria, which seem to be particularly dominant off Peru and Chile. However, a massive reduction of macrobenthos occurs in the core of the OMZ. In the Humboldt Current area the OMZ ranges between <100 and about 600 m, with decreasing thickness in a poleward direction. The OMZ merges into better oxygenated zones towards the deep sea, where large cold-water mega-and macrofauna occupy a dominant role as in the nearshore strip. The Benguela Current OMZ has a similar upper limit but remains shallower. It also hosts giant sulphur bacteria but little is known about the benthic fauna. However, sulphur eruptions and intense hypoxia might preclude the coexistence of significant mega-und macrobenthos. Conversely, off North America the upper limit of the OMZ is considerably deeper (e.g., 500-

show abstract

“…One of the most dramatic responses of inshore species to hypoxia and sulfide events in the Benguela system involves the activities of rock lobsters (Jasus lalandii). They aggregate inshore (within a mile of shore) where the surf oxygenates the water (Baily et al, 1985) and under extreme conditions will "walk out" (migrate) onto the shore in mass strandings (Fig 6) that lead to extensive mortality over days to a month. Recovery time varies with the area affected and whether hydrogen sulfide was produced (Cockcroft, 2001).…”

Section: Benguela Shelf West Africamentioning

confidence: 99%

Effects of natural and human-induced hypoxia on coastal benthos

et al. 2009

View full text Add to dashboard Cite

Abstract. Coastal hypoxia (defined here as <1.42 ml L −1 ; 62.5 µM; 2 mg L −1 , approx. 30% oxygen saturation) develops seasonally in many estuaries, fjords, and along open coasts as a result of natural upwelling or from anthropogenic eutrophication induced by riverine nutrient inputs. Permanent hypoxia occurs naturally in some isolated seas and marine basins as well as in open slope oxygen minimum zones. Responses of benthos to hypoxia depend on the duration, predictability, and intensity of oxygen depletion and on whether H 2 S is formed. Under suboxic conditions, large mats of filamentous sulfide oxidizing bacteria cover the seabed and consume sulfide. They are hypothesized to provide a detoxified microhabitat for eukaryotic benthic communities. Calcareous foraminiferans and nematodes are particularly tolerant of low oxygen concentrations and may attain high densities and dominance, often in association with microbial mats. When oxygen is sufficient to support metazoans, small, soft-bodied invertebrates (typically annelids), often with short generation times and elaborate branchial structures, predominate. Large taxa are more sensitive than small taxa to hypoxia. Crustaceans and echinoderms are typically more sensitive to hypoxia, with lower oxygen thresholds, than annelids, sipunculans, molluscs and cnidarians.

show abstract

Seasonal variation of oxygen deficiency in waters off southern South West Africa in 1975 and 1976 and its relation to the catchability and distribution of the Cape rock lobsterJasus lalandii

Cited by 34 publications

References 0 publications

Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jasus edwardsii on a coastal reef in northern New Zealand

Seasonal changes in depth distribution, sex ratio and size frequency of spiny lobster Jasus edwardsii on a coastal reef in northern New Zealand

El Niño and similar perturbation effects on the benthos of the Humboldt, California, and Benguela Current upwelling ecosystems

Effects of natural and human-induced hypoxia on coastal benthos

Contact Info

Product

Resources

About