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Direct hydroacoustic observations of chokka squid Loligo vulgaris reynaudii spawning activity in deep water
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: M. J. Roberts M. Barange M. R. Lipiński M. R. ProwseUnusual and distinct hydroacoustic targets were observed in November 1996, May 1998 and November 1998 during routine pelagic biomass surveys off the south coast of South Africa. During the November 1996 survey, seven such targets were observed near the bottom... -
Early post-cleavage stages and abnormalities identified in the embryonic development of chokka squid eggs Loligo vulgaris reynaudii
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: A. Oosthuizen M. J. Roberts W. H. H. SauerSix early, post-cleavage embryonic stages for chokka squid Loligo vulgaris reynaudii eggs that were developed in an aquarium are identified and described, expanding the embryonic stages for this species from 14 to 20. The influence of water temperature on embryonic... -
Currents along the Tsitsikamma coast, South Africa, and potential transport of squid paralarvae and ichthyoplankton
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MJ Roberts M van den BergIn July 1998, a bottom-mounted Acoustic Doppler Current Profiler was deployed at 36m depth in the centre of the Tsitsikamma National Park on the eastern Agulhas Bank, South Africa. The purpose was to investigate transport of chokka squid Loligo vulgaris... -
First Lagrangian ROMS–IBM simulations indicate large losses of chokka squid Loligo reynaudii paralarvae from South Africa's Agulhas Bank
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MJ Roberts --- Department of Environmental Affairs, South Africa C Mullon --- , FrancePresent knowledge of ocean currents based on in situ observation and models suggests that passive biological material such as eggs and larvae can be advected offshore away from the Agulhas Bank, South Africa, and hence removed from the ecosystem on... -
Reproductive system and the spermatophoric reaction of the mesopelagic squid Octopoteuthis sicula (Rüppell 1844) (Cephalopoda: Octopoteuthidae) from southern African waters
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: HJT Hoving MR Lipiński JJ VidelerReproductive features of the poorly known oceanic squid Octopoteuthis sicula are described and quantified to gain insight into the reproductive biology of the species. The data are based on 39 complete and partial specimens from southern African waters, collected between... -
Assessing the suitability of commercial fisheries data for local-scale marine spatial planning in South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Chalmers --- Department of Ichthyology and Fisheries Science, South Africa A Oosthuizen --- Park Planning and Development, South African National Parks, South Africa A Götz --- Department of Ichthyology and Fisheries Science, South Africa A Paterson --- South African Institute for Aquatic Biodiversity, South Africa WHH Sauer --- Department of Ichthyology and Fisheries Science, South AfricaThis study integrates fisheries logbook data with observer and vessel monitoring system (VMS) data in order to assess the accuracy of reported data and to develop high-resolution spatial data suitable for use in local-scale marine spatial planning analyses. Spatial assessments... -
A review of the assessments of the major fisheries resources in South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CL de Moor --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa SJ Johnston --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa A Brandão --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa RA Rademeyer --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa JP Glazer --- Branch: Fisheries Management, Department of Agriculture, South Africa LB Furman --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa DS Butterworth --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South AfricaThe waters off South Africa's coastline boast a rich mix of commercially fished species. Quantitative assessments of these marine resources have developed from simple methods first applied in the 1970s, to models that encompass a wide range of methodologies. The... -
Differences in metal compositions and concentrations of sympatric predatory fish and squid from the South Atlantic Ocean
Item type: Journal Article • Journal: African Zoology • Authors: Ryan C Uren --- , South Africa Francois Bothma --- , South Africa Carl D van der Lingen --- , South Africa Hindrik Bouwman --- , South AfricaMetals occur naturally in the environment and in organisms. Organisms at higher trophic levels may contain metals at elevated concentrations, as a result of accumulation from anthropogenic and natural sources, potentially making them more susceptible to detrimental effects, as well... -
Are there long-term temporal trends of size composition and the length– weight relationship? Results for chokka squid Loligo reynaudii during the peak spawning season off the south coast of South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: MR Lipiński --- , South Africa MA Mmethi --- , South Africa D Yemane --- , South Africa J Githaiga-Mwicigi --- , South Africa WHH Sauer --- , South AfricaTemporal trends in the size composition (length frequency) and length–weight (L–W) relationship of chokka squid Loligo reynaudii on the south coast of South Africa were assessed over periods spanning 22 years: length frequencies from 1996 to 2017 (with 15 years... -
Acoustic assessment of the biomass of aggregated chokka squid Loligo reynaudii on its inshore spawning grounds on the southeast coast of South Africa in the season closed for fishing
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: I Hampton --- , South Africa MA Soule --- , South Africa J Mwicigi --- , South AfricaRecent attempts to estimate the biomass of chokka squid Loligo reynaudii on the southeast coast of South Africa by acoustic surveys of the inshore jig-fishing area are described. Pilot surveys of aggregations, covering part of the fishing grounds, were conducted...