A review of the assessments of the major fisheries resources in South Africa

Moor, Carryn L De; Johnston, S. J.; Brandão, Anabela; Rademeyer, RA; Glazer, J.P.; Furman, LB; Butterworth, Doug S

doi:10.2989/1814232x.2015.1070201

Cited by 17 publications

(15 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The changes in the marine environment, including marked reductions in lobster densities off northwest South Africa, are likely to limit lobster recovery in that area, even in the complete absence of fishing (de Moor et al. ). In turn, the null response at Jutten Island suggests lobster no‐take zones north of Dassen Island are unlikely to benefit Bank Cormorants.…”

Section: Discussionmentioning

confidence: 99%

“…A formal stock‐assessment procedure was introduced in 1997 to which a spatial component was added in 2006, but the stock remains well below target levels (de Moor et al. ). The fishery is currently in a poor state (de Moor et al.…”

Section: Introductionmentioning

confidence: 99%

“…The fishery is currently in a poor state (de Moor et al. ; Sink ): available biomass is estimated at <3% of “pristine” (Blamey et al. ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Defining ecologically relevant scales for spatial protection with long‐term data on an endangered seabird and local prey availability

Sherley

Botha

Underhill

et al. 2017

Conservation Biology

View full text Add to dashboard Cite

Human activities are important drivers of marine ecosystem functioning. However, separating the synergistic effects of fishing and environmental variability on the prey base of nontarget predators is difficult, often because prey availability estimates on appropriate scales are lacking. Understanding how prey abundance at different spatial scales links to population change can help integrate the needs of nontarget predators into fisheries management by defining ecologically relevant areas for spatial protection. We investigated the local population response (number of breeders) of the Bank Cormorant (Phalacrocorax neglectus), a range-restricted endangered seabird, to the availability of its prey, the heavily fished west coast rock lobster (Jasus lalandii). Using Bayesian state-space modeled cormorant counts at 3 colonies, 22 years of fisheries-independent data on local lobster abundance, and generalized additive modeling, we determined the spatial scale pertinent to these relationships in areas with different lobster availability. Cormorant numbers responded positively to lobster availability in the regions with intermediate and high abundance but not where regime shifts and fishing pressure had depleted lobster stocks. The relationships were strongest when lobsters 20-30 km offshore of the colony were considered, a distance greater than the Bank Cormorant's foraging range when breeding, and may have been influenced by prey availability for nonbreeding birds, prey switching, or prey ecology. Our results highlight the importance of considering the scale of ecological relationships in marine spatial planning and suggest that designing spatial protection around focal species can benefit marine predators across their full life cycle. We propose the precautionary implementation of small-scale marine protected areas, followed by robust assessment and adaptive-management, to confirm population-level benefits for the cormorants, their prey, and the wider ecosystem, without negative impacts on local fisheries.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Defining ecologically relevant scales for spatial protection with long‐term data on an endangered seabird and local prey availability

Sherley

Botha

Underhill

et al. 2017

Conservation Biology

View full text Add to dashboard Cite

show abstract

“…; De Moor et al . ). Stock assessments of South Africa's west coast rock lobster Jasus lalandii (Milne‐Edwards) rely on abundance estimates from fishery‐dependent catch and effort data from the commercial sector and fishery‐independent capture‐based surveys, together with lobster growth information, as key inputs for the assessment models (De Moor et al .…”

Section: Introductionmentioning

confidence: 97%

“…South Africa's Department of Agriculture, Forestry and Fisheries (DAFF) conducts two annual surveys, an inshore survey with ring nets (also called hoop nets) at depths <30 m and an offshore survey with traps at depths from 15 to 200 m. The harvest from the recreational sector is estimated with an annual telephone survey (De Moor et al . ).…”

Section: Introductionmentioning

confidence: 97%

Potential application of baited remote underwater video to survey abundance of west coast rock lobster Jasus lalandii

Roberson

Attwood

Winker

et al. 2017

Fisheries Management Eco

View full text Add to dashboard Cite

The first assessment of the baited remote underwater video system (BRUVs) for monitoring rock lobster Jasus lalandii (Milne‐Edwards) in South Africa was compared to annual ring net and trap survey data. Count data from 58 BRUVs, 36 ring net and 95 trap samples were fitted with generalised additive models using depth, habitat, time and spatial gradient as independent variables. A power analysis was used to determine the number of samples needed per annum to detect a 5 and 10% increase and decrease in population size. The BRUVs outperformed the nets and traps in terms of sampling effort and were better at detecting changes in abundance of lobster than abundance of three fish species. Considering factors such as cost, analysis time, additional data and environmental impact, traps are the most feasible method in deeper waters but BRUVs could replace nets and traps in depths less than 60 m, low‐density areas and marine reserves.

show abstract

Fisheries yields, climate change, and ecosystem-based management of the Benguela Current Large Marine Ecosystem

Kainge¹,

Kirkman

Estevão³

et al. 2020

Environmental Development

View full text Add to dashboard Cite

A review of the assessments of the major fisheries resources in South Africa

Cited by 17 publications

References 28 publications

Defining ecologically relevant scales for spatial protection with long‐term data on an endangered seabird and local prey availability

Defining ecologically relevant scales for spatial protection with long‐term data on an endangered seabird and local prey availability

Potential application of baited remote underwater video to survey abundance of west coast rock lobster Jasus lalandii

Fisheries yields, climate change, and ecosystem-based management of the Benguela Current Large Marine Ecosystem

Contact Info

Product

Resources

About