Genomic information can aid in the establishment of sustainable management plans for commercially... more Genomic information can aid in the establishment of sustainable management plans for commercially exploited marine fishes, aiding in the long‐term conservation of these resources. The southern African hakes (Merluccius capensis and M. paradoxus) are commercially valuable demersal fishes with similar distribution ranges but exhibiting contrasting life histories. Using a comparative framework based on Pool‐Seq genome‐wide SNP data, we investigated whether the evolutionary processes that shaped extant patterns of diversity and divergence are shared among these two congeneric fishes, or unique to each one. Our findings revealed that M. capensis and M. paradoxus show similar levels of genome‐wide diversity, despite different census sizes and life‐history features. In addition, M. capensis shows three highly structured geographic populations across the Benguela Current region (one in the northern Benguela and two in the southern Benguela), with no consistent genome–environment association...
Characteristics of survivors: growth and nutritional condition of early stages of the hake specie... more Characteristics of survivors: growth and nutritional condition of early stages of the hake species Merluccius paradoxus
The Big Old Fat Fecund Female Fish (BOFFFF) hypothesis is explored quantitatively using an age-st... more The Big Old Fat Fecund Female Fish (BOFFFF) hypothesis is explored quantitatively using an age-structured stock production model in which the usual stock:recruit rela-tionship is replaced by a three-stage recruitment process based on maternal age. The recruitment process is decomposed into three age-dependent stages: 1) number of eggs spawned per batch per female, 2) number of batches spawned per year (related to the length of the spawning season), 3) increased survival of young stages with maternal age. The first two stages together give the stock recruitment potential and can be well justified by experimental observation in many fish species. The third stage is affected by both maternal age and also environmental conditions. The results indi-cate that the number of batches spawned per year is the most important component. They also indicate that a few old fish potentially contribute many times more recruits to the population than many younger fish. It is argued that the concept of...
The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibi... more The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibia and South Africa, have committed to implementing ecosystem-based management (EBM) including an ecosystem approach to fisheries (EAF) in the region, to put in practice the principles of sustainable development in ocean-related matters. There is also recognition of the need for marine spatial planning (MSP) as a process for informing EBM with regard to the allocation and siting of ocean uses so that ecosystem health is ensured and trade-offs between ecosystem services are appropriately dealt with. Marine spatial planning is both an integrated and an area-based process, and this paper produces a spatial characterisation of the BCLME for achieving a common basis for MSP in the region, focusing on the oceanography, biology and fisheries. Recognising spatial variation in physical driving forces, primary and secondary production, trophic structures and species richness, four different subsystems are characterised: (1) north of the Angola–Benguela Front, (2) from the Angola–Benguela Front to Lüderitz, (3) from Lüderitz to Cape Agulhas, and (4) from Cape Agulhas to Port Alfred on the south-east coast of South Africa. Research and monitoring requirements of relevance for MSP and EBM in the region are identified, focusing on understanding variability and change, including with regard to the boundary areas identified for the system. To this end, 14 cross-shelf monitoring transects are proposed (including seven that are already being monitored) to estimate fluxes of biota, energy and materials within and between the subsystems. The usefulness of models for understanding ecosystem variability and changes is recognised and the need for fine-scale resolution of both sampling and modelling for adequate MSP as input to EBM for the often-conflicting interests of conserving biodiversity, and managing fisheries, recreation, offshore oil and gas exploration and exploitation, offshore mining and shipping routes, is emphasised.
Growth of adult chokka squid Loligo reynaudii d’Orbigny was modelled using mantle length and age ... more Growth of adult chokka squid Loligo reynaudii d’Orbigny was modelled using mantle length and age data derived from samples collected over two years (2003 and 2004) from a single, large cohort of mature and spawning squid. A total of 588 statoliths were examined (310 males, 278 females) from individuals of 71–425 mm mantle length (ML). The maximum size of chokka squid was 425 mm ML for males and 263 mm ML for females. The Francis Growth Model and Linear Growth model were selected for further analysis from six models considered. Males and females attain similar ages, although mantle length-based daily growth rates ranged from 0.75 to 1.02 (0.88 quantile _50) mm/day for males and 0.32–0.45 (0.38 quantile _50) mm/day for females, explaining the sexual dimorphism apparent in the sizes of individuals of this species.
Grote, B., Ekau, W., Stenevik, E. K., Clemmesen, C., Verheye, H. M., Lipinski, M. R., and Hagen, ... more 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 re...
Genomic information can aid in the establishment of sustainable management plans for commercially... more Genomic information can aid in the establishment of sustainable management plans for commercially exploited marine fishes, aiding in the long‐term conservation of these resources. The southern African hakes (Merluccius capensis and M. paradoxus) are commercially valuable demersal fishes with similar distribution ranges but exhibiting contrasting life histories. Using a comparative framework based on Pool‐Seq genome‐wide SNP data, we investigated whether the evolutionary processes that shaped extant patterns of diversity and divergence are shared among these two congeneric fishes, or unique to each one. Our findings revealed that M. capensis and M. paradoxus show similar levels of genome‐wide diversity, despite different census sizes and life‐history features. In addition, M. capensis shows three highly structured geographic populations across the Benguela Current region (one in the northern Benguela and two in the southern Benguela), with no consistent genome–environment association...
Characteristics of survivors: growth and nutritional condition of early stages of the hake specie... more Characteristics of survivors: growth and nutritional condition of early stages of the hake species Merluccius paradoxus
The Big Old Fat Fecund Female Fish (BOFFFF) hypothesis is explored quantitatively using an age-st... more The Big Old Fat Fecund Female Fish (BOFFFF) hypothesis is explored quantitatively using an age-structured stock production model in which the usual stock:recruit rela-tionship is replaced by a three-stage recruitment process based on maternal age. The recruitment process is decomposed into three age-dependent stages: 1) number of eggs spawned per batch per female, 2) number of batches spawned per year (related to the length of the spawning season), 3) increased survival of young stages with maternal age. The first two stages together give the stock recruitment potential and can be well justified by experimental observation in many fish species. The third stage is affected by both maternal age and also environmental conditions. The results indi-cate that the number of batches spawned per year is the most important component. They also indicate that a few old fish potentially contribute many times more recruits to the population than many younger fish. It is argued that the concept of...
The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibi... more The three countries of the Benguela Current Large Marine Ecosystem (BCLME), namely Angola, Namibia and South Africa, have committed to implementing ecosystem-based management (EBM) including an ecosystem approach to fisheries (EAF) in the region, to put in practice the principles of sustainable development in ocean-related matters. There is also recognition of the need for marine spatial planning (MSP) as a process for informing EBM with regard to the allocation and siting of ocean uses so that ecosystem health is ensured and trade-offs between ecosystem services are appropriately dealt with. Marine spatial planning is both an integrated and an area-based process, and this paper produces a spatial characterisation of the BCLME for achieving a common basis for MSP in the region, focusing on the oceanography, biology and fisheries. Recognising spatial variation in physical driving forces, primary and secondary production, trophic structures and species richness, four different subsystems are characterised: (1) north of the Angola–Benguela Front, (2) from the Angola–Benguela Front to Lüderitz, (3) from Lüderitz to Cape Agulhas, and (4) from Cape Agulhas to Port Alfred on the south-east coast of South Africa. Research and monitoring requirements of relevance for MSP and EBM in the region are identified, focusing on understanding variability and change, including with regard to the boundary areas identified for the system. To this end, 14 cross-shelf monitoring transects are proposed (including seven that are already being monitored) to estimate fluxes of biota, energy and materials within and between the subsystems. The usefulness of models for understanding ecosystem variability and changes is recognised and the need for fine-scale resolution of both sampling and modelling for adequate MSP as input to EBM for the often-conflicting interests of conserving biodiversity, and managing fisheries, recreation, offshore oil and gas exploration and exploitation, offshore mining and shipping routes, is emphasised.
Growth of adult chokka squid Loligo reynaudii d’Orbigny was modelled using mantle length and age ... more Growth of adult chokka squid Loligo reynaudii d’Orbigny was modelled using mantle length and age data derived from samples collected over two years (2003 and 2004) from a single, large cohort of mature and spawning squid. A total of 588 statoliths were examined (310 males, 278 females) from individuals of 71–425 mm mantle length (ML). The maximum size of chokka squid was 425 mm ML for males and 263 mm ML for females. The Francis Growth Model and Linear Growth model were selected for further analysis from six models considered. Males and females attain similar ages, although mantle length-based daily growth rates ranged from 0.75 to 1.02 (0.88 quantile _50) mm/day for males and 0.32–0.45 (0.38 quantile _50) mm/day for females, explaining the sexual dimorphism apparent in the sizes of individuals of this species.
Grote, B., Ekau, W., Stenevik, E. K., Clemmesen, C., Verheye, H. M., Lipinski, M. R., and Hagen, ... more 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 re...
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Papers by Marek Lipinski