Ocean circulation, Stokes drift, and connectivity of western rock lobster (Panulirus cygnus) population

2011 ◽  
Vol 68 (7) ◽  
pp. 1182-1196 ◽  
Author(s):  
Ming Feng ◽  
Nick Caputi ◽  
James Penn ◽  
Dirk Slawinski ◽  
Simon de Lestang ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
West Coast ◽  
Early Stage ◽  
Austral Summer ◽  
Early Summer ◽  
Stokes Drift ◽  
Rock Lobster ◽  
The West ◽  
Larval Phase ◽  
Panulirus Cygnus

An individual-based model, incorporating outputs of a data-assimilating hydrodynamic model, was developed to investigate the role of ocean circulation in the recruitment processes of western rock lobster ( Panulirus cygnus ) during its 9- to 11-month larval phase off the west coast of Australia. During austral summer, strong northward alongshore winds aid the offshore movement of early-stage model larvae from midshelf hatching sites into open ocean; during austral winter, eastward flows that feed the enhanced Leeuwin Current facilitate onshore movement of late-stage larvae towards nearshore habitats. Stokes drift induced by swells from the Southern Ocean is critical to retain larvae off the west coast. Diurnal migration and temperature-dependent growth are also important. Model larvae hatched in late spring – early summer grow faster because of longer exposure to warm summer temperature, which allows them to be transported towards the coast by the strong onshore flows in winter and reduces their natural mortality. Preliminary source–sink relationship indicates that the population was well mixed off the coast, with higher likelihood of settlement success from hatching sites in the north, mostly due to higher surface temperature. Weighted with the breeding stock distribution, the area between 27.5°S and 29.5°S, including the Abrolhos Islands, is the most important hatching area to the success of settlement.

Jasus lalandii 'walkouts' or mass strandings in South Africa during the 1990s: an overview

2001 ◽  
Vol 52 (8) ◽  
pp. 1085 ◽  
Author(s):  
Andrew C. Cockcroft
Keyword(s):  
South Africa ◽  
West Coast ◽  
The Other ◽  
Fishing Industry ◽  
Low Oxygen ◽  
Rock Lobster ◽  
The West ◽  
Hypoxic Conditions ◽  
Oxygen Conditions ◽  
Mass Mortalities

Faunal mass mortalities are a sporadic, but not uncommon, feature of the West and South coasts of South Africa. Five mass mortalities of West Coast rock lobsterJasus lalandii, including three of the most severe ever recorded in South Africa, occurred in the 1990s and resulted in the stranding of about 2263 tonnes of lobster. The bulk (97%) of the loss occurred in the last three years of the decade. The five events occurred within an 80 km stretch of coastline that straddled two fishing zones and resulted from hypoxic conditions associated with highbiomass dinoflagellate blooms. In each case, the quantity of lobsters stranded was directly related to the extent or duration of low-oxygen conditions. Small females constituted the bulk of the lobster stranded in most events. The lobster fisheries in the affected fishing zones suffered severe impacts. Recovery in one zone appears to be extremely slow, whereas the other zone is more resilient. Not only would a continuation of the trend of increasing frequency and severity of lobster strandings devastate the rock-lobster fishing industry and the employment prospects of small fishing communities, but it could also seriously affect the ecology of the region.

Effects of temperature and food density on the survival and growth of early stage phyllosoma of the western rock lobster, Panulirus cygnus

Aquaculture ◽  
2004 ◽  
Vol 242 (1-4) ◽  
pp. 207-215 ◽  
Author(s):  
Grant C. Liddy ◽  
Bruce F. Phillips ◽  
Greg B. Maguire
Keyword(s):  
Early Stage ◽  
Food Density ◽  
Rock Lobster ◽  
Survival And Growth ◽  
Effects Of Temperature ◽  
Panulirus Cygnus

scholarly journals Seasonal Variation of Temperature and Salinity of Surface Waters of the British Columbia Coast

1953 ◽  
Vol 10 (3) ◽  
pp. 125-145 ◽  
Author(s):  
G. L. Pickard ◽  
D. C. McLeod
Keyword(s):  
British Columbia ◽  
West Coast ◽  
Sea Water ◽  
Deep Ocean ◽  
Vancouver Island ◽  
Early Summer ◽  
The West ◽  
Queen Charlotte Islands ◽  
Land Drainage ◽  
Run Off

Grand monthly means of daily observations of surface sea-water temperature and salinity from twelve light stations along the British Columbia coast during the 13 years 1935 to 1948 have been analysed. In general the temperatures reach a minimum of 45°F. ± 1° (7.2 °C. ± 0.5°) in January and February. The maximum varies from 50° to 64°F. (10° to 18 °C.) in August. The warmest waters occur in bays protected from wind action, and the coldest waters occur in regions of turbulent mixing due to wind or strong currents. The salinity along the mainland coast is a minimum in early summer, associated with the maximum run-off from melting snow. Along the west coast of Vancouver Island the minimum occurs in mid-winter, associated with maximum precipitation which is not stored as snow in this region. At the southern and northern tip of the Queen Charlotte Islands there is little or no variation of salinity because there is no land drainage of consequence in the vicinity.In passes between Georgia Strait and the sea where the waters are mixed to homogeneity by strong tidal currents the annual variation of temperature and salinity is reduced, and in some cases entirely suppressed.On the west coast of Vancouver Island it is shown that the annual cycle is affected by the dominant winds and upwelling of deep ocean waters.

Mitochondrial DNA variation of the west-coast rock lobster, Jasus lalandii: marked genetic diversity differences among sampling sites

2007 ◽  
Vol 58 (12) ◽  
pp. 1130 ◽  
Author(s):  
Conrad A. Matthee ◽  
Andrew C. Cockcroft ◽  
Keshni Gopal ◽  
Sophie von der Heyden
Keyword(s):  
Genetic Diversity ◽  
West Coast ◽  
Haplotype Network ◽  
Phylogeographic Structure ◽  
Rrna Gene ◽  
Rock Lobster ◽  
The West ◽  
Mt Dna ◽  
Dna Variation ◽  
Intensive Exploitation

Jasus lalandii (Milne-Edwards 1837), the west-coast rock lobster, occurs in the shallow, cool–temperate waters along the south and west coasts of southern Africa. This species has a long history of intensive exploitation, which has had a significant impact on population numbers in the past. To enhance our current understanding of lobster population structuring, genetic data from the mitochondrial (mt) DNA 16S rRNA gene was generated for 235 adult individuals collected at eight sampling sites. Most individuals (59.6%) share a common haplotype and 35 unique haplotypes were dispersed throughout the range. In total, 97.2% of the variation was found among individuals within sampling sites and 2.8% was among sites. Pairwise ΦST analyses revealed shallow, yet significant structure between Hout Bay individuals and some other sampling sites. The J. lalandii haplotype network indicates a starlike structure with no geographic signal; however, genetic diversity sharply decreases towards the edges of the species distribution. The general lack of phylogeographic structure among J. lalandii populations probably results from the absence of strong barriers to larval dispersal. Based on our mtDNA data there is no justification for the recognition of separate fishing stocks, but the high genetic diversities of populations at Hout Bay and Cape Hangklip, the latter currently outside of marine protected areas, makes these populations critical to conservation efforts.

scholarly journals Mitigation of incidental mortality of Australian sea lions in the west coast rock lobster fishery

2008 ◽  
Vol 5 ◽  
pp. 335-344 ◽  
Author(s):  
R Campbell ◽  
D Holley ◽  
D Christianopolous ◽  
N Caputi ◽  
NG Gales
Keyword(s):  
West Coast ◽  
Rock Lobster ◽  
The West ◽  
Sea Lions ◽  
Lobster Fishery ◽  
Incidental Mortality

Corrigendum to: Ocean currents and the larval phase of Australian western rock lobster, Panulirus cygnus

2002 ◽  
Vol 53 (3) ◽  
pp. 731 ◽  
Author(s):  
David A. Griffin ◽  
John L. Wilkin ◽  
Chris F. Chubb ◽  
Alan F. Pearce ◽  
Nick Caputi
Keyword(s):  
Transport Model ◽  
Early Stage ◽  
Larval Survival ◽  
Ocean Currents ◽  
Larval Transport ◽  
Offshore Wind ◽  
Larval Phase ◽  
Leeuwin Current ◽  
The North ◽  
Panulirus Cygnus

The return of Panulirus cygnus larvae to the coast of Western Australia after nearly a year at sea and its modulation by ocean currents were addressed with an individual-based larval-transport model. The simulations implied that offshore wind-driven transport of larvae is balanced by onshore geostrophic flow. Additional simulations revealed that vertical migration behaviour was essential to larval survival through its impact on advection. The six years simulated include two of high, two of low, and two of average puerulus settlement. The most robust interannual difference of the simulations was that, when coastal sea level was low and the Leeuwin Current was weak, more early-stage larvae were lost to the north and west under the influence of the wind. Conversely, many late-stage model larvae were carried south of the fishery in years when the Leeuwin Current was strong. The fraction of model larvae remaining or arriving offshore of the fishery and metamorphosing was essentially constant from year to year, so the variation in observed puerulus settlement was not explained by the model. The results imply that the nonadvective effects of fluctuations in the Leeuwin (e.g., on temperature and primary production) were primarily responsible for the high variation in natural settlement.

Improving the catch efficiency of the West Coast rock lobster, Jasus lalandii

2000 ◽  
Vol 51 (6) ◽  
pp. 613 ◽  
Author(s):  
D. Loewenthal ◽  
S. Mayfield ◽  
G. M. Branch
Keyword(s):  
Weight Loss ◽  
South African ◽  
West Coast ◽  
Capture Rate ◽  
Catch Rate ◽  
Rock Lobster ◽  
The South ◽  
The West ◽  
The Relationship

The South African commercial rock-lobster industry employs an average soak time of 22 h for traps. Experiments were undertaken to test (1) the rate of bait loss with soak time and the effect that protection of the bait has on bait loss, (2) the relationship between catch rate (numbers per trap) and soak time for traps with either protected or unprotected bait, and (3) the effect of two bait types (whole maasbanker and hake heads) on the catch of rock lobsters. There were substantial losses of unprotected bait within 6 h; substantially less weight loss was observed from protected bait even after a 48-h soak time. The numbers of rock lobsters caught in traps with unprotected bait were low relative to the capture rate with protected bait. The highest capture rate occurred after 6 h for unprotected bait and 6–12 h for protected bait. There was no significant effect of bait type (maasbanker v. hake heads) on the number or size of rock lobsters. To optimize catch efficiency, the commercial industry should use protected bait and soak times as short as 6–12 h.

Ocean currents and the larval phase of Australian western rock lobster, Panulirus cygnus

2001 ◽  
Vol 52 (8) ◽  
pp. 1187 ◽  
Author(s):  
David A. Griffin ◽  
John L. Wilkin ◽  
Chris F. Chubb ◽  
Alan F. Pearce ◽  
Nick Caputi
Keyword(s):  
Transport Model ◽  
Early Stage ◽  
Larval Survival ◽  
Ocean Currents ◽  
Larval Transport ◽  
Offshore Wind ◽  
Larval Phase ◽  
Leeuwin Current ◽  
The North ◽  
Panulirus Cygnus

The return of Panulirus cygnus larvae to the coast of Western Australia after nearly a year at sea and its modulation by ocean currents were addressed with an individual-based larval-transport model. The simulations implied that offshore wind-driven transport of larvae is balanced by onshore geostrophic flow. Additional simulations revealed that vertical migration behaviour was essential to larval survival through its impact on advection. The six years simulated include two of high, two of low, and two of average puerulus settlement. The most robust interannual difference of the simulations was that, when coastal sea level was low and the Leeuwin Current was weak, more early-stage larvae were lost to the north and west under the influence of the wind. Conversely, many late-stage model larvae were carried south of the fishery in years when the Leeuwin Current was strong. The fraction of model larvae remaining or arriving offshore of the fishery and metamorphosing was essentially constant from year to year, so the variation in observed puerulus settlement was not explained by the model. The results imply that the nonadvective effects of fluctuations in the Leeuwin (e.g., on temperature and primary production) were primarily responsible for the high variation in natural settlement.

The South African Fisheries: A Preliminary Survey of Historical Sources

2001 ◽  
pp. 167-180
Author(s):  
Lance van Sittert
Keyword(s):  
South African ◽  
West Coast ◽  
Marine Resources ◽  
Historical Records ◽  
Preliminary Survey ◽  
Rock Lobster ◽  
The South ◽  
Historical Sources ◽  
The West

Lance van Sittert explores the historical records concerning the exploitation of marine resources along the West Coast of Africa, using them to provide evidence of the commerical importance of the West Coast over the East or South. The date demonstrates a boom-bust cycle along the West Coast, pertaining to whales, snoek, guano, rock lobster, hake, and pilchard.

scholarly journals Flight behaviour of the manuka chafers, Pyronota festiva (Fabricius) and Pyronota setosa (Given) (Coleoptera: Melolonthinae), on the flipped soils of Cape Foulwind on the West Coast of New Zealand

2018 ◽  
Vol 71 ◽  
pp. 255-261
Author(s):  
Richard J. Townsend ◽  
Jessica E. Dunbar ◽  
Trevor A. Jackson
Keyword(s):  
New Zealand ◽  
West Coast ◽  
Early Summer ◽  
Late Spring ◽  
Field Observations ◽  
The West ◽  
Flight Behaviour ◽  
Sweep Net

Some species in the genus Pyronota are known to be serious pests of pasture. The establishment of new dairy pastures on recently flipped soils on Cape Foulwind, Buller provided a unique opportunity to investigate the flight behaviour and biology of Pyronota festiva and P. setosa from 2008—2012. Flight behaviour was monitored by fixed-vane interruption traps and by field observations. Adults of both species flew through late spring/early summer (Nov—Dec) of each year and seasonal flight timing was consistent between years. Pyronota festiva flight timing and duration were similar to those previously reported in the literature and were slightly female dominated. Pyronota setosa flights started one to two weeks in advance of P. festiva and were dominated by males (>95%). Female P. setosa were rarely observed flying and were rarely caught in sweep-net sampling. Pyronota setosa beetles were never observed swarming or congregating and feeding on the foliage of mānuka. These differences in flight behaviour may help to explain the field observations that P. festiva can rapidly invade new pastures while P. setosa populations appear to spread more slowly.

Sign in / Sign up

Export Citation Format

Share Document