Diel variability in bottom trawl catches and feeding activity of the Cape hakes off the west coast of South Africa

Catch share management was implemented in the bottom trawl sector of the West Coast Groundfish fishery in 2011 to address a range of issues including high bycatch and discard rates. The catch share programwas designed to remove the incentives to discard through full catch accounting, tradeable quotas, increased flexibility in fishing, and penalties for catch overages. We assess the effectiveness of the program in meeting its environmental objectives by comparing discard weights, proportions, and variability from 2004–2010 with 2011–2016. We analyzed these metrics for species managed using quota, including historically overfished stocks, as well as for non-quota species caught in the fishery. Discard amounts decreased over time for all species and declined to historic lows after the implementation of the program, remaining low through 2016 with much less inter-annual variability. Mean annual discards of two highly-targeted quota species, sablefishand Dover sole, showed the greatest decreases, falling by 97 and 86%, respectively. The discard proportion of overfished quota species fell by 50% on average. The unanticipated decline in discards of non-quotaspecies as well as the decreased variability in discard amounts for all species indicate that the incentives produced by catch share management provided additional ecosystem benefits.

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Picture postcards versus production landscapes: The case of wind farms in the West Coast region of South Africa

Suid-Afrikaanse Tydskrif vir Natuurwetenskap en Tegnologie ◽

10.4102/satnt.v33i1.1199 ◽

2014 ◽

Vol 33 (1) ◽

Cited By ~ 1

Author(s):

A. Lombard

Keyword(s):

South Africa ◽

West Coast ◽

Wind Farms ◽

The West ◽

Coast Region

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Surficial sediments on the continental margin off the west coast of South Africa

Marine Geology ◽

10.1016/0025-3227(77)90037-8 ◽

1977 ◽

Vol 23 (4) ◽

pp. 305-337 ◽

Cited By ~ 16

Author(s):

G.F. Birch

Keyword(s):

South Africa ◽

Continental Margin ◽

West Coast ◽

Surficial Sediments ◽

The West

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Shark–Cetacean trophic interaction, Duinefontein, Koeberg, (5 Ma), South Africa

South African Journal of Science ◽

10.17159/sajs.2015/20140453 ◽

2015 ◽

Vol Volume 111 (Number 11/12) ◽

Cited By ~ 3

Author(s):

Romala Govender ◽

Keyword(s):

South Africa ◽

Cause Of Death ◽

West Coast ◽

Trophic Interaction ◽

The West ◽

Carcharodon Carcharias ◽

Inverted Position ◽

Bite Marks ◽

Shark Teeth ◽

Long Time

Abstract This study forms part of a larger project to reconstruct the Mio-Pliocene marine palaeoenvironment along South Africa’s west coast. It documents the shark–cetacean trophic interaction during the Zanclean (5 Ma) at Duinefontein (Koeberg). The damage described on the fragmentary cetacean bones was compared with similar damage observed on fossils from Langebaanweg, a Mio-Pliocene site on the west coast of South Africa, and data present in the literature. This comparison showed that the damage was the result of shark bites. The state of preservation makes it difficult to determine if the shark bite marks were the cause of death or as a result of scavenging. The presence of the bite marks on the bone would, however, indicate some degree of skeletonisation. Bite marks on some cranial fragments would suggest that the cetacean’s body was in an inverted position typical of a floating carcass. The preservation of the material suggests that the bones were exposed to wave action resulting in their fragmentation as well as abrasion, polishing and rolling. It also suggests that the cetacean skeletons were exposed for a long time prior to burial. The morphology of the bites suggests that the damage was inflicted by sharks with serrated and unserrated teeth. Shark teeth collected from the deposit include megalodon (Carcharodon megalodon), white (Carcharodon carcharias) as well as mako (Isurus sp. and Cosmopolitodus hastalis) sharks, making these sharks the most likely predators/scavengers.

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