Trends in shore-based angling effort determined from aerial surveys: a case study from KwaZulu-Natal, South Africa

Mann, BQ; Mann, Judy

doi:10.2989/1814232x.2020.1740785

Cited by 9 publications

(7 citation statements)

References 28 publications

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“…A decrease in fishing effort is corroborated by fishery compliance patrols in KZN that reported large declines in recreational effort and in catches of all marine invertebrate species between 1996 and 2004, with numbers of mussel fishers declining by 42% (Kruger and Schleyer 2005). Aerial surveys revealed a 23% reduction in the recreational shore-based linefishing effort in KZN from the 1990s to the present (Mann and Mann-Lang 2020). Access and opportunity to participate in recreational fisheries in KZN therefore appear to have shrunk.…”

Section: Discussionmentioning

confidence: 91%

“…Access and opportunity to participate in recreational fisheries in KZN therefore appear to have shrunk. Likely factors are a ban on beach-driving since 2002, which limits access to remote areas, an increased crime rate during the 1990s, and lifestyle changes associated with post-industrialisation, such as less free time and a larger choice of leisure activities (Mann et al 2008;Arlinghaus et al 2014;Mann and Mann-Lang 2020).…”

Section: Discussionmentioning

confidence: 99%

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Trends in mussel cover, density and size at exploited and unexploited intertidal reefs in eastern South Africa

Steyn

Groeneveld

Santos

et al. 2022

African Journal of Marine Science

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The brown mussel Perna perna is the dominant indigenous mussel along the east coast of South Africa, where it is harvested by recreational and subsistence fishers. High fishing pressure near metropolitan areas has led to declining abundance, and closure of some reefs to fishing in 1998. We estimated trends in mussel population dynamics at exploited and unexploited sites over a 27-year period (1993-2019) along fixed transects. Trends in recreational fishing effort were inferred from yearly permit sales and existing catch statistics.At high fishing effort, short-term trends in mussel cover and densities were inversely related to fishing effort at three of four sites, while a fourth site was influenced by intermittent breaching of a nearby estuary. Mussel size was inversely related to densities. The effects of longer term harvesting bans were partially obscured by sharp declines in fishing effort across the entire recreational fishery. Seasonal and interannual patterns in cover and density were partially synchronised among sites, indicating environmental forcing at similar time-scales. The longterm dataset was invaluable in disentangling the relative effects of fishing and environmental factors on mussel population dynamics and should be continued as a baseline for assessing future climate-induced effects on rocky shore biota.

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Section: Discussionmentioning

confidence: 91%

Section: Discussionmentioning

confidence: 99%

Trends in mussel cover, density and size at exploited and unexploited intertidal reefs in eastern South Africa

Steyn

Groeneveld

Santos

et al. 2022

African Journal of Marine Science

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“…north coast and released into the surf-zone. This area was considered to be safer for release as it is more secluded and has lower fishing pressure compared to the central Durban area (Mann & Mann-Lang, 2020).…”

Section: Methodsmentioning

confidence: 99%

The fate and movements of aquarium‐released giant trevally Caranx ignobilis inferred from acoustic telemetry

et al. 2023

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Movements of four adult giant trevally Caranx ignobilis were tracked using passive acoustic telemetry after being released from uShaka Sea World Aquarium in Durban, South Africa, where they had been kept on display for a period of 8 years. All four individuals were detected on a large network of deployed acoustic receivers for a minimum of 3 months to a maximum of over 6 years. Their movements were compared to 43 wild‐caught and tagged C. ignobilis over a similar period and two individuals adopted movement behavior similar to that of their conspecifics, including repeated annual seasonal migrations to a known spawning aggregation site. This study shows that with good animal husbandry, indigenous fish kept in captivity can be released back into the wild and not only survive but adopt natural movement behavior and contribute to future generations of their species.

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“…In this study, movements of ranging fish were undoubtedly under-sampled because very little shore angling takes place in remote areas far from beach access points in the MPA (Mann et al, 2016a;Mann and Mann-Lang, 2020). In addition, estimated a non-reporting rate of 42 % by members of the angling public, which would further hamper data collection on ranging fishes that had been recaptured.…”

Section: Rangingmentioning

confidence: 99%

“…Spillover, which is the net export of adult fish from a no-take area (Abesamis and Russ, 2005), implies that fishes will move from a no-take area where there is a high concentration of individuals, to areas where fishing has reduced the number and size of fish (Kramer and Chapman, 1999;Kerwath et al, 2013). While there may be some true density-dependent spillover of D. petersi from the no-take zones into the adjacent exploited zones within the iSimangaliso MPA, the remoteness of many of the areas and the low fishing effort adjacent to the no-take zones, especially since the implementation of the beach vehicle ban in 2002 (Mann et al, 2016a;Mann and Mann-Lang, 2020), has likely reduced the gradient in fish density between the zones (Mann et al, 2016a), with the result that much of the dispersal observed in this study is more likely to have been as a consequence of variability in individual movement patterns. This observation is supported by the fact that ranging movements were undertaken by 4 fish tagged in an exploited zone, 1 of which moved into a no-take zone and the other 3 swam right through a no-take zone and were recaptured in an exploited zone on the other side (Table 1).…”

Section: Rangingmentioning

confidence: 99%

Movement patterns and growth rate of cavebass Dinoperca petersi (Pisces: Dinopercidae) in the iSimangaliso Marine Protected Area, South Africa

Mann

Jordaan²,

Daly³

2021

West Ind. Oc. J Mar. Sci.

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Dinoperca petersi is a relatively common fish species caught in the line-fishery in KwaZulu-Natal (KZN), South Africa. Yet, little is known about the biology and ecology of this species. Movement patterns and growth rate of this species were studied based on data obtained from a long-term tag-recapture study conducted in the iSimangaliso Marine Protected Area in northern KZN between 2001-2019. Results showed that D. petersi is a highly resident species with a linear home-range size of 290-405 m. While most fish showed high site fidelity, 8.8 % of the tagged fish showed wider ranging movements of 2.4-90 km. However, only 5 fish showed movements out of no-take zones into adjacent exploited areas, suggesting limited adult spillover. Growth rate of tagged fish was found to be reasonably slow compared to other sympatric predatory reef fish with an average growth rate of 61.76 mm y–1 for smaller fish (gα = 300) and 9.58 mm y–1 for larger fish (gβ = 550). Based on these life history characteristics, options for the future conservation and management of this species are discussed.

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Trends in shore-based angling effort determined from aerial surveys: a case study from KwaZulu-Natal, South Africa

Cited by 9 publications

References 28 publications

Trends in mussel cover, density and size at exploited and unexploited intertidal reefs in eastern South Africa

Trends in mussel cover, density and size at exploited and unexploited intertidal reefs in eastern South Africa

The fate and movements of aquarium‐released giant trevally Caranx ignobilis inferred from acoustic telemetry

Movement patterns and growth rate of cavebass Dinoperca petersi (Pisces: Dinopercidae) in the iSimangaliso Marine Protected Area, South Africa

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