Progress report on recommendations from the International review panel report for the 2013 International Fisheries Stock assessment workshop:sardine

The international review panel report (MARAM/IWS/DEC13/General/4 Final Report) contained the following recommendations pertinent to sardine in response to key questions put to them at the annual stock assessment review meeting held at UCT from 2-6 December 2013. Comments on any progress in response to these recommendations are inserted in italics. As a general point of background information, the Small Pelagic Scientific Working Group agreed earlier in 2014 to finalise OMP-14 based on a single sardine stock operating model only, but coupled with some spatial management, the spirit of which is to be a “warm up period” with the expectation that the next OMP will quite likely require spatial management components. The development of new operating models and a new OMP is to be brought forward, commencing in early 2015 with the aim of being finalised before the end of 2016

Jellyfication of marine ecosystems as a likely consequence of overfishing small pelagic fishes: Lessons from the Benguela

Changes in two contrasting ecosystems of the Benguela upwelling region, one dominated at mid-trophic level by jellyfishes (Namibia, northern Benguela ecosystem, where small pelagic fish abundance has been severely depleted) and one still dominated by small pelagic fishes (South Africa, southern Benguela) were compared in an effort to determine ecosystem trajectories under different exploitation regimes. The role of small pelagic fishes (clupeoids) was highlighted in the context of their importance in maintaining interactions in marine ecosystems. In particular, we examined trophic cascades and possible irreversible changes that promote the proliferation of jellyfishes in marine systems. We found that the presence of large populations of small pelagic fishes has a fundamental role in preserving beneficial trophic interactions in these marine ecosystems. The implications of trophic cascades, such as those observed in the northern Benguela, for ecosystem-based management were apparent. In addition, this comparison provides contrasting case studies to inform the development of management scenarios that avoid ecosystem shifts that affect predators and reduce the value of fisheries production.Web of Scienc

Accommodating Dynamic Oceanographic Processes and Pelagic Biodiversity in Marine Conservation Planning

Pelagic ecosystems support a significant and vital component of the ocean's productivity and biodiversity. They are also heavily exploited and, as a result, are the focus of numerous spatial planning initiatives. Over the past decade, there has been increasing enthusiasm for protected areas as a tool for pelagic conservation, however, few have been implemented. Here we demonstrate an approach to plan protected areas that address the physical and biological dynamics typical of the pelagic realm. Specifically, we provide an example of an approach to planning protected areas that integrates pelagic and benthic conservation in the southern Benguela and Agulhas Bank ecosystems off South Africa. Our aim was to represent species of importance to fisheries and species of conservation concern within protected areas. In addition to representation, we ensured that protected areas were designed to consider pelagic dynamics, characterized from time-series data on key oceanographic processes, together with data on the abundance of small pelagic fishes. We found that, to have the highest likelihood of reaching conservation targets, protected area selection should be based on time-specific data rather than data averaged across time. More generally, we argue that innovative methods are needed to conserve ephemeral and dynamic pelagic biodiversity

Ectoparasites infecting the heads and gills of commercially valuable marine fishes in South Africa

The South African marine environment is highly diverse, containing >12 000 species of flora and fauna. However, the state of knowledge of marine fish parasites in South African waters is still relatively poor. This study used opportunistic sampling to examine the heads and gills of several commercially valuable marine fish species for ectoparasites with the aim of increasing knowledge of marine parasite biodiversity in South Africa. Samples were collected in 2015 and 2016 from commercial fishing operations, local fishers and research cruises by the Department of Forestry, Fisheries and the Environment and were stored frozen until dissection. The head region, gills and opercula from altogether 621 individual fish from 16 host species were examined. In total, 22 parasite taxa, comprising seven monogeneans and 15 copepods, were recorded, with one new host record and 13 new geographic records catalogued for South Africa. This study increases the knowledge of marine parasite biodiversity in South Africa.              &nbsp

Differences in metal compositions and concentrations of sympatric predatory fish and squid from the South Atlantic Ocean

Metals 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 as passing them on to consumers. The concentrations of thirty metals were quantified in hake (Merluccius capensis), kingklip (Genypterus capensis), monkfish (Lophius vomerinus) and chokka (Loligo reynaudii) collected from the South Atlantic Ocean of South Africa in February 2017 and February 2019, using inductively coupled plasma mass spectrometry. Metal concentrations and composition in nektobenthic chokka differed significantly from the three demersal fish predators (hake, kingklip, and monkfish). Demersal fish metal concentrations and relative pattern compositions (fingerprints) were similar. Because the samples were collected within an 80 km radius, the differences are likely as a result of a combination of factors, such as diet, habitat (depth), and differences in the physiological regulation of metals between cephalopods and fish, rather than location. Based on South African estimated daily intake, total hazard quotient and European Union limits for mercury, cadmium and lead, these four economically important species from the South Atlantic Ocean are safe for human consumption. Plankton, herbivorous marine species, and larger predators, such as sharks and dolphins, should be studied to obtain further insight into metals as baseline for monitoring possible future pollution and effects from climate change, trophic transfer, toxic effects, and human consumer safety. Keywords: cadmium, chokka squid, lead, mercury, muscle tissue, South Afric

The quantitative use of parasite data in multistock modelling of South African sardine (Sardinops sagax) 1

Differences in parasite infection have previously been used to distinguish between fish stocks. We demonstrate a novel use of parasite prevalence-by-length data to inform quantitatively on stock mixing. An initial two mixing stock hypothesis proved consistent with biological and survey data, suggesting that there are different stocks of sardine off the west and south coasts of South Africa. That hypothesis assumed that only recruits moved from the west to the south stock. However, new “tetracotyle”-type metacercarian parasite bio-tag data indicate a need to allow older fish to move between the stocks as well. We demonstrate extension of bio-tagging to inform on the plausibility of population structure hypotheses by including parasite prevalence-by-length data in the model’s likelihood. Our method enables the estimation of the magnitude of mixing between semidiscrete stocks, providing more precise estimates of annual movement. Such improved precision may be important in better informing future movement hypotheses and thereby management. Our research provides a framework to use to inform quantitatively on stock structure and movement hypotheses for other fish species with bio-tagging data

Parasite community structure as a predictor of host population structure: An example using Callorhinchus capensis

This paper describes the parasite community structure of the Cape elephant fish or St Joseph shark (Callorhinchus capensis) caught off the West and South Coast of South Africa between 2010 and 2015. These data were used to build species accumulation curves (SAC) and calculate biodiversity indices including rarefied species richness, Shannon Weiner's diversity index, Simpson's index and Pielou's J index. The biodiversity indices were correlated with the host's biological data to determine how these affected the parasite community structure and provide insight into the host's population structure. The parasites identified in C. capensis (n = 259) include a cestode (Gyrocotyle plana), two monogeneans (Callorhynchicotyle callorhynchi and Callorhinchicola multitesticulatus), an isopod (Anilocra capensis) and a leech (Branchellion sp.). Gyrocotyle plana was the most prevalent at 71.43% and the monogenean C. callorhynchi had the highest mean abundance (1.55 ± 0.45 parasites.fish−1) and the highest mean infection intensity (4.79 ± 0.66 parasites.infected fish−1). The SAC and biodiversity measures indicate a uniform parasite community across the sampled host population, suggesting a highly interactive shark community with no evidence for population structure. These results show that parasite community structure can be used to infer their host's population structure. Keywords: Species accumulation curves, Callorhinchus spp., Cestoda, Monogenea, Parasite ecology, Marine biodiversit

First account of the metazoan parasite fauna of oilfish Ruvettus pretiosus Cocco, 1829 (Perciformes: Gempylidae) in South African waters

Parasites are an important but neglected component of ecosystems that can be used as indicators of host biology and ecology. In the present study, the metazoan parasite assemblage of Ruvettus pretiosus, an understudied but widely distributed predatory gempylid, caught off South Africa was surveyed. A total of seven parasite taxa, including four new infection records (Bolbosoma capitatum, Rhadinorhynchus sp., Hepatoxylon trichiuri and Anisakis sp.), two new locality records (B. capitatum and Rhipidocotyle sp.) as well as the ectoparasitic copepod Sagum foliaceus and the cestode Tentacularia coryphaenae were recovered from the eight specimens examined.Keywords: Benguela, mesopelagic, parasitism, teleos

Climate and fishing simultaneously impact small pelagic fish in the oceans around the southernmost tip of Africa

11 pages, 6 figures, 2 tables, supplementary material https://www.frontiersin.org/articles/10.3389/fmars.2022.1031784/full#supplementary-material.-- Data availability statement: The original contributions presented in the study are included in the article/Supplementary Material. Further inquiries can be directed to the corresponding author/sClimate and fisheries interact, often synergistically, and may challenge marine ecosystem functioning and, ultimately, seafood provision and human wellbeing that depend on them. Holistic and integrative approaches aiming at evaluating the spatial overlap between these major stressors are crucial for identifying marine regions and key fish species that require conservation priority to prevent possible future collapses. Based on highly resolved information on environmental conditions and fishing pressure from the Southern Benguela and the Agulhas Bank ecosystems off South Africa, we identified the main areas where small pelagic fish species (European anchovy Engraulis encrasicolus, Pacific sardine Sardinops sagax, and West Coast round herring Etrumeus whiteheadi) have been highly impacted in terms of unfavourable environmental conditions and fishing pressure over the period 1993-2018. We termed these areas cumulative “hotspots” of climate change and fishing impact. We also identified fishing grounds where environmental conditions are now more favourable for these pelagic fish species, terming these “bright spots” of climate change. Environmental conditions and fishing intensity show contrasting patterns between the Southern Benguela and the Agulhas Bank ecosystems, with the Southern Benguela region accumulating most of the cumulative hotspots and showing the most negative trends in CPUE (a proxy for local fish abundance). Contrastingly, bright spots, identified on the south coast but also south of Cape Town, showed more positive trends in CPUE, suggesting that they may support sustainable growth of the small pelagic fishery in the medium term. Focussing future fishing effort on these bright spots may serve to alleviate pressure on the doubly and highly impacted cumulative hotspots from the western side of the southernmost tip of AfricaThe study was carried out within the European Union’s Horizon 2020 research and innovation programme under grant agreement No 817578 (TRIATLAS project) and the Spanish Ministry of Science and Innovation grants agreements N° PID2020-118097RB-I00 (ProOceans) and PID2021-124831OA-I00 (SOSPEN). The authors acknowledge financial support from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S, hereafter SO). FR, LS, JS and MC were supported by TRIATLAS. FR also received support from, SO, and the Ramón y Cajal programme (Spanish Ministerio de Ciencia e Innovación, RYC2020-030078-I)Peer reviewe