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1

Gordoa, Ana, and Carlos M. Duarte. "Size-Dependent Spatial Distribution of Hake (Merluccius capensis and Merluccius paradoxus) in Namibian Waters." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 11 (November 1, 1991): 2095–99. http://dx.doi.org/10.1139/f91-248.

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Data on hake (Merluccius capensis and Merluccius paradoxus) abundance along the Namibian coast showed both species to have strongly aggregated spatial distributions. In addition, average fish size increased with depth, suggesting that the formation of hake aggregation is based on size-dependent shoaling behaviour. Hake spacing was size dependent with areal fish density and biomass being scaled to the −5 and −2 power, respectively, of fish length. The equations describing the size dependence of the areal fish density were log density (fish∙m−2) = 5.06-4.91 log size (cm) for M. capensis and log density (fish∙m−2) = 5.28-4.74 log size (cm) for (M. paradoxus). The maximum areal densities, presumably corresponding to those within the shoals, exceeded those described by the equations above by 20- and 13-fold for M. capensis and M. paradoxus, respectively. The size dependence of hake spacing implies that fishing pressure targeting aggregates of small hake (i.e. shallow shoals) should have a disproportionate effect on fish mortality and recruitment compared with similar fishing pressure targeting aggregates of larger hake (i.e. deep shoals).
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2

PEREZ, JULIANA, and EVA GARCIA-VAZQUEZ. "Genetic Identification of Nine Hake Species for Detection of Commercial Fraud." Journal of Food Protection 67, no. 12 (December 1, 2004): 2792–96. http://dx.doi.org/10.4315/0362-028x-67.12.2792.

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This study describes the 5S rRNA gene as a simple and reliable one-step PCR-based genetic marker that allows unambiguous identification of Merluccius paradoxus, Merluccius senegalensis, Merluccius australis, Merluccius gayi, Merluccius bilinearis, Merluccius hubbsi, and Macruronus magellanicus. The marker is based on differences in length at the nontranscribed spacer within the 5S rRNA genes and is robust enough for identification of processed products, such as fish fingers and other precooked commercial hake. Further restriction fragment length polymorphism analysis at the mitochondrial cytochrome b gene can distinguish Merluccius merluccius and Merluccius capensis. The application of these markers for routine works such as surveys of quality and labeling of commercial hakes is suggested due to their accuracy, low price, and possible automation for large-scale surveys.
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3

VENNEMANN, INGO H., T. EUGENE CLOETE, GARY A. DYKES, and ALEXANDER VON HOLY. "Bacterial Populations Associated with the Processing of Cape Hake (Merluccius capensis and Merluccius paradoxus)." Journal of Food Protection 57, no. 11 (November 1, 1994): 1016–18. http://dx.doi.org/10.4315/0362-028x-57.11.1016.

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Numbers of bacteria associated with Cape hake from catching through processing to the finished product and final spoilage were determined by pour plating on Sea Water Agar (SWA). Subsequently, a total of 1,020 predominant bacteria from the different stages were isolated and identified to genus level. A significant reduction (p<0.05) in bacterial numbers after the first wash during processing ashore and a significant increase (p<0.05) after day 3 of refrigerated storage of final product were observed. No significant differences in bacterial numbers between the different stages onboard the trawler or during processing ashore were apparent. Psychrotrophic bacteria from predominantly four genera, namely Moraxella, Pseudomonas, Corynebacterium and Micrococcus, were isolated in this study. The relative proportions of these organisms was found to change only to a small extent during the chilled processing chain, with the genus Moraxella (46 to 57%) predominating. After several days of refrigerated storage, however, the relative proportion of Pseudomonas increased (from 34 to 90%) leaving this genus predominating in spoiled product.
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4

Grote, Britta, Werner Ekau, Erling K. Stenevik, Catriona Clemmesen, Hans M. Verheye, Marek R. Lipinski, and Wilhelm Hagen. "Characteristics of survivors: growth and nutritional condition of early stages of the hake species Merluccius paradoxus and M. capensis in the southern Benguela ecosystem." ICES Journal of Marine Science 69, no. 4 (February 27, 2012): 553–62. http://dx.doi.org/10.1093/icesjms/fss020.

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Abstract Grote, B., Ekau, W., Stenevik, E. K., Clemmesen, C., Verheye, H. M., Lipinski, M. R., and Hagen, W. 2012. Characteristics of survivors: growth and nutritional condition of early stages of the hake species Merluccius paradoxus and M. capensis in the southern Benguela ecosystem. – ICES Journal of Marine Science, 69: 553–562. Larval mortality in marine fish is strongly linked to characteristic traits such as growth and condition, but the variability in these traits is poorly understood. We tried to identify the variability in growth in relation to conditions leading to greater survival chances for early stages of Cape hake, Merluccius paradoxus and M. capensis, in the Benguela upwelling ecosystem. During two cruises in 2007 and one cruise in 2008, hake larvae and juveniles were caught. Otolith microstructures revealed a larval age ranging from 2 to 29 days post-hatching (dph), whereas juvenile age was 67–152 dph. RNA:DNA ratios, used to evaluate nutritional condition, were above the relevant threshold level for growth. No strong coupling between growth and condition was detected, indicating a complex relationship between these factors in the southern Benguela ecosystem. Merluccius paradoxus juveniles caught in 2007 (the surviving larvae of 2006) had significantly higher larval growth rates than larvae hatched in 2007 and 2008, possibly indicating selection for fast growth in 2006. High selection pressure on growth could be linked to predation avoidance, including cannibalism.
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5

Lombarte, A., and A. Castellón. "Interspecific and intraspecific otolith variability in the genus Merluccius as determined by image analysis." Canadian Journal of Zoology 69, no. 9 (September 1, 1991): 2442–49. http://dx.doi.org/10.1139/z91-343.

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Morphological variation in the sagittal otoliths of six species of the genus Merluccius was compared. The outlines of the otoliths were broken down numerically and classified according to numerical taxonomic methods. The results of this classification indicated that the specific characters of the sagittae emerge with individual growth, so that the otoliths from small individuals of various species exhibit plesiomorphic characters and are quite similar to one another. The otoliths from individuals longer than 20 cm can be classified into two geographic and phylogenetic groups: a Euro-African group (M. merluccius, M. capensis, and M. paradoxus) with plesiomorphic features, and an American group (M. bilinearis, M. productus, and M. gayi).
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6

Kainge, P., N. Bahamon, CH Bartholomae, JN Kathena, AK van der Plas, and A. Gordoa. "Stock-environment recruitment analysis for Namibian Cape hake Merluccius capensis." African Journal of Marine Science 35, no. 4 (December 2013): 555–64. http://dx.doi.org/10.2989/1814232x.2013.862509.

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7

Osborne, R. F., Y. C. Melo, M. D. Hofmeyr, and D. W. Japp. "Serial spawning and batch fecundity of Merluccius capensis and M. Paradoxus." South African Journal of Marine Science 21, no. 1 (June 1, 1999): 211–16. http://dx.doi.org/10.2989/025776199784125944.

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8

Caputo, M., S. Elwen, T. Gridley, SA Kohler, JP Roux, PW Froneman, and JJ Kiszka. "Dietary plasticity of two coastal dolphin species in the Benguela upwelling ecosystem." Marine Ecology Progress Series 669 (July 8, 2021): 227–40. http://dx.doi.org/10.3354/meps13755.

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Defining the trophic relationships of marine predators and their dietary preferences is essential in understanding their role and importance in ecosystems. Here we used stable isotope analysis of skin samples (δ15N values reflecting trophic level and δ13C values reflecting foraging habitat) to investigate resource partitioning and spatial differences of the feeding ecology of dusky dolphins Lagenorhynchus obscurus and Heaviside’s dolphins Cephalorhynchus heavisidii from 2 coastal study sites separated by 400 km along the coast of central (Walvis Bay) and southern (Lüderitz) Namibia in the Benguela upwelling ecosystem. Overall, isotopic niches of both predators were significantly different, indicating partitioning of resources and foraging habitats. Despite their smaller body size, Heaviside’s dolphins fed at a significantly higher trophic level than dusky dolphins. Stable isotope mixing models revealed that both species fed on high trophic level prey (i.e. large Merluccius spp., large Sufflogobius bibarbatus, and Trachurus t. capensis) at Walvis Bay. The diet of both dolphin species included smaller pelagic fish and squid at Lüderitz. Spatial differences highlight that Heaviside’s and dusky dolphins may exhibit dietary plasticity driven by prey availability, and that they likely form distinct population segments. Important prey for both dolphin species, specifically Merluccius spp. and T. t. capensis, are the main target of trawl fisheries in the Benguela upwelling ecosystem, highlighting potential resource overlap between dolphins and fisheries.
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9

Barange, M., I. Hampton, S. C. Pillar, and M. A. Soule. "Determination of Composition and Vertical Structure of Fish Communities Using in situ Measurements of Acoustic Target Strength." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 1 (January 1, 1994): 99–109. http://dx.doi.org/10.1139/f94-012.

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A split-beam echo-sounder was used to estimate in situ acoustic target strengths (TS) of fish from a number of different fish communities on the South African continental shelf. The TS and size distributions (obtained by aimed trawling) were used to describe the size structure and vertical distribution of these communities. TS distributions obtained from several monospecific populations of juvenile Cape hake (Merluccius capensis), the dominant species present, were self-consistent, and there was good correspondence between modes in the TS and length distributions of juvenile hake, adult round herring (Etrumeus whiteheadi), anchovy (Engraulis capensis) recruits, pelagic goby (Sufflogobius bibarbatus), horse mackerel (Trachurus trachurus capensis), and ribbon fish (Lepidopus caudatus). Average TS values for all these species, both per individual and normalized by weight, are presented and compared with published values. The use of TS information in studies of the small-scale community structure and dynamics of fish populations is discussed. It is concluded that the method can be effective on low-density, multispecific assemblages such as those in our study, avoiding many of the pitfalls of conventional net sampling.
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10

De Almeida, Louise, William Froneman, and Brett Pletschke. "Optimization of a Cytochrome-P450-Monooxygenase-1A-Mediated EROD Assay in the Cape Hake Species Merluccius capensis and Merluccius paradoxus (Pisces)." Enzyme Research 2011 (November 22, 2011): 1–8. http://dx.doi.org/10.4061/2011/108395.

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Cytochrome P450 monooxygenase 1A (CYP1A) is induced by several planar toxic compounds, for example, polychlorinated biphenyls (PCBs) and the induction of this protein is often measured in terms of CYP1A-mediated 7-ethoxyresorufin-O-deethylase (EROD) activity. This study was aimed at developing this assay in the Cape hake species Merluccius capensis and Merluccius paradoxus (considered one stock). Microsomal fractions were obtained from frozen fish liver samples by differential centrifugation. Fluorimetric and spectrophotometric analysis of the EROD assay resulted in the spectrophotometric (at 572 nm) detection method being selected, as this method resulted in a lower degree of variability and demonstrated higher reproducibility. The activity in the EROD assay was enhanced in the presence of NADPH, and the addition of dicumarol (phase II enzyme inhibitor) to the reaction mixtures prevented the underestimation of this assay by the inhibition of DT-diaphorase. In summary, an EROD assay was established for use in Cape hake species.
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11

Hurtado, J. L., P. Montero, and A. J. Borderias. "Extension of shelf life of chilled hake (Merluccius capensis) by high pressure/Prolongación de la vida útil de merluza (Merluccius capensis) sometida a altas presiones conservada en refrigeración." Food Science and Technology International 6, no. 3 (June 2000): 243–49. http://dx.doi.org/10.1177/108201320000600307.

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Vacuum packed hake muscle subjected to 400 MPa (three 5-min cycles) at 7 °C proved to be more stable at chilled temperatures (2-3 °C), and sensorially acceptable, until 43 days of storage in comparison with the nine days for the non-pressurized hake. The lot pressurized at 400 MPa had the appearance of cooked muscle. The microbial load was initially reduced by two log units by pressurization at 400 MPa. Trimethylamine nitrogen (TMA-N) values were also very low. Pressurization had no effect on dimethylamine nitrogen (DMA-N) production. The lot pressurized at 400 MPa showed slower increase in drip loss from day 15 of storage. In the lot subjected to 200 MPa (three 5-min cycles) at 7 °C, which retained the appearance of raw fish, microorganisms were one log unit lower than in the non-pressurized sample and TMA-N was lower. In conclusion, the chilled shelf life was prolonged by about one week in the lot pressurized at 200 MPa and about two weeks in the lot pressurized at 400 MPa.
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12

Preński, Leszek Bruno. "Studies on hake, Merluccius capensis Castelnau, 1861, from off Namibia. II. Studies on food and feeding." Acta Ichthyologica et Piscatoria 16, no. 2 (December 31, 1986): 3–21. http://dx.doi.org/10.3750/aip1986.16.2.01.

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13

Miralles, Laura, Gonzalo Machado-Schiaffino, and Eva Garcia-Vazquez. "Genetic markers reveal a gradient of hybridization between cape hakes (Merluccius capensis and Merluccius paradoxus) in their sympatric geographic distribution." Journal of Sea Research 86 (February 2014): 69–75. http://dx.doi.org/10.1016/j.seares.2013.11.009.

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14

Wilhelm, Margit R., Jean-Paul Roux, Coleen L. Moloney, and Astrid Jarre. "Data from fur seal scats reveal when Namibian Merluccius capensis are hatched and how fast they grow." ICES Journal of Marine Science 70, no. 7 (July 19, 2013): 1429–38. http://dx.doi.org/10.1093/icesjms/fst101.

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Abstract Wilhelm, M. R., Roux, J-P., Moloney, C. L., and Jarre, A. 2013. Data from fur seal scats reveal when Namibian Merluccius capensis are hatched and how fast they grow. – ICES Journal of Marine Science, 70: . Scat samples were collected regularly at several breeding colonies of Cape fur seals along the Namibian coast. Merluccius capensis otoliths were obtained from these samples, identified, and measured. Cohorts were easily distinguishable using otolith length measurements converted to fish total length. Growth rates of 2- to 21-month-old hake and hatch dates for each of 15 cohorts were estimated from September 1994 to October 2009 (1994–2008 cohorts) using a Schnute growth function and a non-linear mixed-effects model. The function describing growth of these young hake was length Lt (cm) at age t (years) Lt = 3.17 + (25.0 − 3.17) × [1 − e−0.665 × (t − 0.140)]/[1 − e−0.665 × (1.74–0.140)]. Cohort-specific random effects showed a population hatch date estimate of 31 July (austral winter), varying by 94 days among cohorts, from 31 May (1996 cohort) to 1 September (2004 cohort). The mean growth rate from ages 6 to 12 months was 1.26 cm month−1 for the population, ranging between 0.97 cm month−1 (1996 cohort) and 1.38 cm month−1 (2004 cohort). As this rate is almost double the previously estimated value, which is currently used in the stock assessment models, this result may have major implications for the current stock assessment results and the management of the stock. Re-examination of growth rates needs to be extended to older fish.
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15

Grant, WS, RW Leslie, and II Becker. "Genetic stock structure of the southern African hakes Merluccius capensis and M. paradoxus." Marine Ecology Progress Series 41 (1987): 9–20. http://dx.doi.org/10.3354/meps041009.

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16

Gordoa, Ana, and Joseph E. Hightower. "Changes in Catchability in a Bottom-Trawl Fishery for Cape Hake (Merluccius capensis)." Canadian Journal of Fisheries and Aquatic Sciences 48, no. 10 (October 1, 1991): 1887–95. http://dx.doi.org/10.1139/f91-224.

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Management of the Cape hake (Merluccius capensis) stock off the coasts of Angola and Namibia has been based on surplus production modeling, which incorporates an assumption of constant catchability. Results of least-squares catch-at-age analysis and virtual population analysis were used to estimate catchability from 1968 to 1986. Estimated catchability was either relatively constant or gradually increasing from 1968 to 1978, but fluctuated considerably between about 1979 and 1983. The fluctuations may have been due to an inverse relationship between catchability and abundance or to environmental factors affecting fish distribution. The period of highest estimated catchability corresponded to the period of lowest estimated abundance and below-average water temperatures. If management is based on the assumption of constant catchability but catchability is inversely related to abundance, the risk of overfishing will be greatest when the stock is at the lowest levels. Future assessments should place increased reliance on survey data or incorporate an appropriate model of catchability changes.
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17

Macpherson, E., and A. Gordoa. "Effect of prey densities on cannibalism in Cape hake (Merluccius capensis) off Namibia." Marine Biology 119, no. 1 (April 1994): 145–49. http://dx.doi.org/10.1007/bf00350116.

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18

Van Der Lingen, C. D., and T. W. Miller. "Spatial, ontogenetic and interspecific variability in stable isotope ratios of nitrogen and carbon of Merluccius capensis and Merluccius paradoxus off South Africa." Journal of Fish Biology 85, no. 2 (June 17, 2014): 456–72. http://dx.doi.org/10.1111/jfb.12436.

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19

Kadila, Hendrina K., Dietlinde N. Nakwaya, Mike Butler, and Johannes A. Iitembu. "Insights into feeding interactions of shallow water cape hake (Merluccius capensis) and cape horse mackerel (Trachurus capensis) from the Northern Benguela (Namibia)." Regional Studies in Marine Science 34 (February 2020): 101071. http://dx.doi.org/10.1016/j.rsma.2020.101071.

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20

Henning, SS, M. Krügel, and M. Manley. "Prevalence of Kudoa thyrsites (Myxozoa) in South African sardine Sardinops sagax, kingklip Genypterus capensis, and Cape hakes Merluccius capensis and M. paradoxus." African Journal of Marine Science 41, no. 3 (October 7, 2019): 261–68. http://dx.doi.org/10.2989/1814232x.2019.1649190.

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21

Cardoso, Carlos L., Rogério O. Mendes, Jorge A. Saraiva, Paulo R. Vaz-Pires, and Maria L. Nunes. "Quality Characteristics of High Pressure-Induced Hake (Merluccius capensis) Protein Gels with and without MTGase." Journal of Aquatic Food Product Technology 19, no. 3-4 (October 29, 2010): 193–213. http://dx.doi.org/10.1080/10498850.2010.506255.

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22

Kathena, Johannes N., Anders Nielsen, Uffe Høgsbro Thygesen, and Casper W. Berg. "Hake species ( Merluccius capensis and M. paradoxus ) assessment in the Benguela Current Large Marine Ecosystem." Environmental Development 17 (January 2016): 193–201. http://dx.doi.org/10.1016/j.envdev.2015.11.011.

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23

Herrero, Ana M., and Mercedes Careche. "Prediction of frozen storage time of Cape hake (Merluccius capensis andMerluccius paradoxus) by instrumental methods." Journal of the Science of Food and Agriculture 86, no. 13 (2006): 2128–33. http://dx.doi.org/10.1002/jsfa.2586.

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24

von der Heyden, Sophie, Marek R. Lipinski, and Conrad A. Matthee. "Mitochondrial DNA analyses of the Cape hakes reveal an expanding, panmictic population for Merluccius capensis and population structuring for mature fish in Merluccius paradoxus." Molecular Phylogenetics and Evolution 42, no. 2 (February 2007): 517–27. http://dx.doi.org/10.1016/j.ympev.2006.08.004.

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25

von der Heyden, S., M. R. Lipinski, and C. A. Matthee. "Species-specific genetic markers for identification of early life-history stages of Cape hakes, Merluccius capensis and Merluccius paradoxus in the southern Benguela Current." Journal of Fish Biology 70, sb (April 2007): 262–68. http://dx.doi.org/10.1111/j.1095-8649.2007.01409.x.

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26

Hoareau, T. B., A. W. Klopper, S. M. R. Dos Santos, C. J. Oosthuizen, and P. Bloomer. "Evaluating the resolution power of new microsatellites for species identification and stock delimitation in the Cape hakes Merluccius paradoxus and Merluccius capensis (Teleostei: Merlucciidae)." Journal of Fish Biology 86, no. 5 (May 2015): 1650–57. http://dx.doi.org/10.1111/jfb.12669.

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27

Wilhelm, MR, SC Paulus, and S. Kashava. "New age-determination method based on fast growth rate of Cape hake Merluccius capensis in Namibia." African Journal of Marine Science 41, no. 2 (April 3, 2019): 119–24. http://dx.doi.org/10.2989/1814232x.2019.1581659.

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28

Badenhorst, A. "Development of the chondrocranium of the shallow-water Cape hake Merluccius capensis (Cast.). Part 1: Neurocranium." South African Journal of Zoology 24, no. 1 (January 1989): 33–48. http://dx.doi.org/10.1080/02541858.1989.11448131.

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29

Badenhorst, A. "Development of the chondrocranium of the shallow-water Cape hake Merluccius capensis (Cast.). Part 2: Viscerocranium." South African Journal of Zoology 24, no. 1 (January 1989): 49–57. http://dx.doi.org/10.1080/02541858.1989.11448132.

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30

IITEMBU, JOHANNES A., TODD W. MILLER, KOJI OHMORI, ABRAHAM KANIME, and SEAN WELLS. "Comparison of ontogenetic trophic shift in two hake species, Merluccius capensis and Merluccius paradoxus, from the Northern Benguela Current ecosystem (Namibia) using stable isotope analysis." Fisheries Oceanography 21, no. 2-3 (February 13, 2012): 215–25. http://dx.doi.org/10.1111/j.1365-2419.2012.00614.x.

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31

Shoopala, ENG, MR Wilhelm, and SC Paulus. "Stock separation of the shallow-water hake Merluccius capensis in the Benguela ecosystem using otolith shape analysis." African Journal of Marine Science 43, no. 1 (January 2, 2021): 1–14. http://dx.doi.org/10.2989/1814232x.2020.1855246.

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32

Attwood, Colin G., Samantha L. Petersen, and Sven E. Kerwath. "Bycatch in South Africa's inshore trawl fishery as determined from observer records." ICES Journal of Marine Science 68, no. 10 (November 1, 2011): 2163–74. http://dx.doi.org/10.1093/icesjms/fsr162.

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Abstract Attwood, C. G., Petersen, S. L., and Kerwath, S. E. 2011. Bycatch in South Africa's inshore trawl fishery as determined from observer records. – ICES Journal of Marine Science, 68: 2163–2174. Ship-based observer data were analysed to describe the volume, composition, utilization, and size structure of catches made by South Africa's inshore trawlers. The sampling rate was 3.5% of all trawls, including unsorted and discard samples. In all, 137 nominal species were recorded. Analysis of species composition separated the trawling grounds into seven areas, providing a framework for stratifying the ground for catch estimation and for selection of representative areas for conservation. The target species, Merluccius capensis and Austroglossus pectoralis, made up 58% of the pre-discard catch. Trachurus trachurus, Pterogymnus laniarius, Raja spp., and Chelidonichthys spp. constituted another 23%. Pre-discard catch volumes of the entire fleet were estimated. The average annual pre-discard catch of M. capensis and A. pectoralis was 9653 and 504 t, respectively, closely matching landing statistics. Argyrosomus inodorus, Rhabdosargus globiceps, Argyrozona argyrozona, and Atractoscion aequidens averaged 294, 230, 107, and 83 t annually, respectively, indicating significant overlap with the handline fishery for A. inodorus and A. argyrozona. A comparison of species composition in unsorted and discard samples revealed the species being preferentially retained. Argyrosomus inodorus and A. aequidens were trawled mainly below their size at maturity. Management needs to consider other species when determining catch or effort limits and area restrictions.
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REED, CECILE, CHAGANTI KALAVATI, KEN MACKENZIE, CATHERINE COLLINS, and WILLY HEMMINGSEN. "Pseudalataspora vanderlingeni n. sp. (Myxosporea: Bivalvulida) from gall bladders of the Cape hakes Merluccius capensis Castelnau, and M. paradoxus Franca (Teleostei: Merlucciidae)." Zootaxa 4497, no. 3 (October 9, 2018): 422. http://dx.doi.org/10.11646/zootaxa.4497.3.6.

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A new species of myxosporean parasite is described from the gall bladders of the hakes Merluccius capensis Castelnau and M. paradoxus Franca (Pisces: Teleostei) caught off the west and south coasts of South Africa. The new species, Pseudalataspora vanderlingeni, is described morphologically and molecularly and compared with the 15 other species of Pseudalataspora previously described from marine fish. Although a molecular description is available on GenBank for only one of these 15 species, the morphological description supports the status of P. vanderlingeni as a new species. Earlier reports, without detailed descriptions, of Leptotheca sp. and Ceratomyxa sp. from the same hosts caught off Namibia were very likely to have been of P. vanderlingeni. These earlier studies reported high prevalences of infection, similar to those of >60% described in the present study. The effects of fixation and freezing on the dimensions of spores of Pseudalataspora spp. are described, and the status of the genus Pseudalataspora within the family Ceratomyxidae is discussed.
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34

Voges, Elizabeth, Ana Gordoa, Chris Hans Bartholomae, and John G. Field. "Estimating the probability of different levels of recruitment for Cape hakes Merluccius capensis off Namibia, using environmental indices." Fisheries Research 58, no. 3 (November 2002): 333–40. http://dx.doi.org/10.1016/s0165-7836(01)00400-3.

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35

Grant, W. Stewart, Inga I. Becker, and Rob W. Leslie. "Evolutionary divergence between sympatric species of southern African Hakes, Merluccius capensis and M. paradoxus. I. Electrophoretic analysis of proteins." Heredity 61, no. 1 (August 1988): 13–20. http://dx.doi.org/10.1038/hdy.1988.86.

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36

Gordoa, A., and E. Macpherson. "Diurnal variation in the feeding activity and catch rate of cape hake (Merluccius capensis and M. paradoxus) off Namibia." Fisheries Research 12, no. 4 (December 1991): 299–305. http://dx.doi.org/10.1016/0165-7836(91)90014-7.

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37

Wilhelm, Margit R., Coleen L. Moloney, Sarah C. Paulus, Suama Kashava, Faye R. V. Brinkman, Anja K. van der Plas, Wendy M. West, Astrid Jarre, and Jean-Paul Roux. "Biannual otolith zonation of Cape hake (Merluccius capensis) in response to fish physiology and environment in the northern Benguela." Journal of Marine Systems 188 (December 2018): 98–108. http://dx.doi.org/10.1016/j.jmarsys.2017.08.001.

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38

Wilhelm, M. R., C. L. Moloney, S. Paulus, and J.-P. Roux. "Fast growth inferred for northern Benguela shallow-water hake Merluccius capensis using annual survey- and monthly commercial length-frequency distributions." Fisheries Research 193 (September 2017): 7–14. http://dx.doi.org/10.1016/j.fishres.2017.03.001.

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39

Valpine, Perry de, and Ray Hilborn. "State-space likelihoods for nonlinear fisheries time-series." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 9 (September 1, 2005): 1937–52. http://dx.doi.org/10.1139/f05-116.

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State-space models are commonly used to incorporate process and observation errors in analysis of fisheries time series. A gap in analysis methods has been the lack of classical likelihood methods for nonlinear state-space models. We evaluate a method that uses weighted kernel density estimates of Bayesian posterior samples to estimate likelihoods (Monte Carlo Kernel Likelihoods, MCKL). Classical likelihoods require integration over the state-space, and we compare MCKL to the widely used errors-in-variables (EV) method, which estimates states jointly with parameters by maximizing a nonintegrated likelihood. For a simulated, linear, autoregressive model and a Schaefer model fit to cape hake (Merluccius capensis × M. paradoxus) data, classical likelihoods outperform EV likelihoods, which give asymptotically biased parameter estimates and inaccurate confidence regions. Our results on the importance of integrated state-space likelihoods also support the value of Bayesian analysis with Monte Carlo posterior integration. Both approaches provide valuable insights and can be used complementarily. Previously, Bayesian analysis was the only option for incorporating process and observation errors with complex nonlinear models. The MCKL method provides a classical approach for such models, so that choice of analysis approach need not depend on model complexity.
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40

Thygesen, Uffe Høgsbro, Kasper Kristensen, Teunis Jansen, and Jan E. Beyer. "Intercalibration of survey methods using paired fishing operations and log-Gaussian Cox processes." ICES Journal of Marine Science 76, no. 4 (January 8, 2019): 1189–99. http://dx.doi.org/10.1093/icesjms/fsy191.

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Abstract We present a statistical method for intercalibration of fishery surveys methods, i.e. determining the difference in catchability and size selectivity of two methods, such as trawl gears or vessels, based on data from paired fishing operations. The model estimates the selectivity ratios in each length class by modelling the size distribution of the underlying population at each station and the size-structured clustering of fish at small temporal and spatial scales. The model allows for overdispersion and correlation between catch counts in neighbouring size classes. This is obtained by assuming Poisson-distributed catch numbers conditional on unobserved log-Gaussian variables, i.e. the catch is modelled using log-Gaussian Cox processes. We apply the method to catches of hake (Merluccius paradoxus and M. capensis) in 341 paired trawl hauls performed by two different vessels, viz. the RV Dr Fridtjof Nansen and the FV Blue Sea, operating off the coast of Namibia. The results demonstrate that it is feasible to estimate the selectivity ratio in each size class, and to test statistically the hypothesis that the selectivity is independent of size or species. For the specific case, we find that differences between size classes and species are statistically significant.
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41

Rubio-Rodríguez, Nuria, Sara M. de Diego, Sagrario Beltrán, Isabel Jaime, Maria Teresa Sanz, and Jordi Rovira. "Supercritical fluid extraction of the omega-3 rich oil contained in hake (Merluccius capensis–Merluccius paradoxus) by-products: Study of the influence of process parameters on the extraction yield and oil quality." Journal of Supercritical Fluids 47, no. 2 (December 2008): 215–26. http://dx.doi.org/10.1016/j.supflu.2008.07.007.

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42

Cooper, Rachel, Anthony Leiman, and Astrid Jarre. "An analysis of the structural changes in the offshore demersal hake (Merluccius capensis and M. paradoxus) trawl fishery in South Africa." Marine Policy 50 (December 2014): 270–79. http://dx.doi.org/10.1016/j.marpol.2014.06.006.

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43

Moreno, Helena M., José Carballo, and A. Javier Borderías. "Study of two different cold restructuring processes using two different qualities of hake (Merluccius capensis ) muscle, with addition of microbial transglutaminase." Journal of the Science of Food and Agriculture 89, no. 8 (April 15, 2009): 1346–51. http://dx.doi.org/10.1002/jsfa.3592.

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44

de Koning, Adrianus J., Shirley Milkovitch, and Theodora H. Mol. "The origin of free fatty acids formed in frozen cape hake mince (Merluccius capensis, castelnau) during cold storage at −18°C." Journal of the Science of Food and Agriculture 39, no. 1 (1987): 79–84. http://dx.doi.org/10.1002/jsfa.2740390109.

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45

Becker, Inga I., W. Stewart Grant, Ralph Kirby, and Frank T. Robb. "Evolutionary divergence between sympatric species of southern African Hakes, Merluccius capensis and M. paradoxus. II. restriction enzyme analysis of mitochondrial DNA." Heredity 61, no. 1 (August 1988): 21–30. http://dx.doi.org/10.1038/hdy.1988.87.

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46

Johnsen, Espen. "Improving the precision of length frequency distribution estimates from trawl surveys by including spatial covariance—using Namibian Merluccius capensis as an example." Fisheries Research 62, no. 1 (April 2003): 7–20. http://dx.doi.org/10.1016/s0165-7836(02)00275-8.

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47

Grote, B., EK Stenevik, W. Ekau, HM Verheye, MR Lipiński, and W. Hagen. "Spawning strategies and transport of early stages of the two Cape hake species,Merluccius paradoxusandM. capensis, in the southern Benguela upwelling system." African Journal of Marine Science 34, no. 2 (August 2012): 195–204. http://dx.doi.org/10.2989/1814232x.2012.675040.

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48

Grote, Britta, Wilhelm Hagen, Marek R. Lipinski, Hans M. Verheye, Erling K. Stenevik, and Werner Ekau. "Lipids and fatty acids as indicators of egg condition, larval feeding and maternal effects in Cape hakes (Merluccius paradoxus and M. capensis)." Marine Biology 158, no. 5 (January 26, 2011): 1005–17. http://dx.doi.org/10.1007/s00227-011-1626-6.

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de Koning, Adrianus J., and Theodora H. Mol. "Quantitative quality tests for frozen fish: Soluble protein and free fatty acid content as quality criteria for hake (Merluccius capensis) stored at −18°C." Journal of the Science of Food and Agriculture 54, no. 3 (1991): 449–58. http://dx.doi.org/10.1002/jsfa.2740540316.

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50

Wilhelm, M. R., J. P. Roux, C. L. Moloney, and A. Jarre. "Biannual otolith-zone formation of young shallow-water hake Merluccius capensis in the northern Benguela: age verification using otoliths sampled by a top predator." Journal of Fish Biology 87, no. 1 (May 20, 2015): 1–16. http://dx.doi.org/10.1111/jfb.12684.

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