Article
Fisheries
Vladimir Laptikhovsky, Gavan Cooke, Christopher Barrett, Sophie Lozach, Eleanor MacLeod, Daniel Oesterwind, Edel Sheerin, Michael Petroni, Leigh Barnwall, Jean-Paul Robin, Louise Allcock, Anne Marie Power
Summary: The study found that European squid reproduces in the Celtic Sea and western part of the English Channel, while veined squid was not found. Differentiating between the two species can be based on egg size and embryonic stage.
FISHERIES RESEARCH
(2021)
Article
Marine & Freshwater Biology
M. R. Lipinski, M. A. Mmethi, D. Yemane, J. Githaiga-Mwicigi, W. H. H. Sauer
Summary: Temporal trends in size composition and length-weight relationship of chokka squid on the south coast of South Africa were examined over a 22-year period. While no significant long-term changes were observed in mean lengths, there was a short-term drop in average length in certain years, possibly linked to the introduction of an additional closed season. Parameters of the length-weight relationship remained stable over the years, with males showing a higher prevalence of starvation compared to females, potentially due to spawning behavior.
AFRICAN JOURNAL OF MARINE SCIENCE
(2021)
Article
Fisheries
Vladimir Laptikhovsky, A. Louise Allcock, Leigh Barnwall, Christopher Barrett, Gavan Cooke, Christian Drerup, Christopher Firmin, Sophie Lozach, Eleanor MacLeod, Daniel Oesterwind, Michael Petroni, Jean-Paul Robin, Edel Sheerin, Anne-Marie Power, Graham J. Pierce
Summary: Through the analysis of data collected over the past 30 years by scientists from the UK, Germany, France, and Ireland, as well as observations from multinational Citizen Science, it was found that the spawning grounds of L. forbesii form an external semi-circle around the spawning grounds of L. vulgaris, and L. forbesii utilizes the North Sea more extensively than L. vulgaris. Seasonally, the position of the spawning grounds is influenced by local temperature conditions, with spawning occurring from November to July.
ICES JOURNAL OF MARINE SCIENCE
(2022)
Article
Environmental Sciences
Victor Duchesne, Andre St-Hilaire, Yves Gratton
Summary: The study developed a method to determine the role of currents in lake charr spawning success and suggested that selecting the right hydrodynamic conditions is crucial for egg survival. By combining fluid mechanics and biology, the model proposed critical entrainment and resuspension velocities, as well as ideal depths for spawning. The findings provide valuable insights for researchers and authorities in conservation efforts for lake charr populations.
JOURNAL OF GREAT LAKES RESEARCH
(2021)
Article
Oceanography
Lisa Hancke, Michael J. Roberts, David Smeed, Fatma Jebri
Summary: The formation of the cold ridge on the Agulhas Bank was investigated using various data sources including satellite-tracked drifters, in situ measurements, and satellite observations. The study found that the cold ridge is induced by coastal upwelling along the Tsitsikamma coast during austral summer, driven by easterly winds and westward flowing coastal currents. The formation of the cold ridge is influenced by Agulhas Current intrusions, as well as the passing of Natal Pulse, which leads to the generation of cyclonic eddies and advects water masses along the 100 m isobath.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2023)
Article
Oceanography
Zoe Jacobs, Mike Roberts, Fatma Jebri, Meric Srokosz, Stephen Kelly, Warwick Sauer, Jorn Bruggeman, Ekaterina Popova
Summary: The Agulhas Bank, off the coast of South Africa, is a vital area for fisheries due to its complex biophysical mechanisms. The presence of the "cold ridge" plays a crucial role in the productivity of the area and potentially impacts the recruitment of important species such as squid.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Oceanography
Sarah Asdar, Zoe L. Jacobs, Ekaterina Popova, Margaux Noyon, Warwick H. Sauer, Michael J. Roberts
Summary: Climate change poses significant threats to the Agulhas Bank fishery, particularly the chokka squid fishery. Our simulations show that increased sea surface temperature and current velocity may pose risks to squid recruitment and growth, while food availability is expected to have a minor impact.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Oceanography
Jorn Bruggeman, Zoe L. Jacobs, Ekaterina Popova, Warwick H. H. Sauer, Jessica M. Gornall, Robert J. W. Brewin, Michael J. Roberts
Summary: Squid species exhibit interannual variability in population size primarily due to environmental variability. This study focuses on the growth and survival of Loligo reynaudii during its early paralarval stage and explores the relationship between environmental variability and catch. By developing models for prey availability, predation pressure, and individual squid growth, the study finds a strong correlation between modelled biomass at the end of the paralarval stage and catch per unit effort (CPUE) in the subsequent season. This suggests that the paralarval stage is a bottleneck, and understanding its dynamics can help predict catch with a nine-month lag.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Multidisciplinary Sciences
Narumi Tsugeki, Kai Nakane, Hideyuki Doi, Natsuki Ochi, Michinobu Kuwae
Summary: Environmental DNA (eDNA) is an important tool for assessing aquatic species dynamics. This study investigated the use of sedimentary DNA to track Daphnia population dynamics and resting egg production. The results showed that the concentration of sedimentary DNA was inconsistent with population abundance but highly correlated with resting egg production. This provides critical insights for using sedimentary DNA as a monitoring tool for egg production dating back 100 years.
SCIENTIFIC REPORTS
(2022)
Article
Environmental Sciences
Joachim Pander, Roser Casas-Mulet, Juergen Geist
Summary: In this study, we evaluated the feasibility of including groundwater-influenced hinterland drainage systems (HDS) as functional habitats in river restoration approaches. By using brown trout eggs as bioindicators, we tested the functionality of spawning grounds in a groundwater-influenced HDS compared to those not influenced by groundwater. The results showed that the mean egg mortality in the HDS was 33% lower than in the non-groundwater-influenced spawning grounds, whereas the mean larval mortality was highest in the HDS (95%) compared to the other sites. These findings suggest that if measures are taken to increase oxygen availability within HDS, they could be incorporated into an efficient river restoration strategy.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2023)
Article
Marine & Freshwater Biology
Melania Agullo, Sandra Heras, Jose-Luis Garcia-Marin, Manuel Vera, Alba Abras, Laia Planella, Maria Ines Roldan
Summary: This study assessed the genetic diversity within spawning grounds of the blue and red shrimp Aristeus antennatus in the Western Mediterranean Sea. The results showed high connectivity among the spawning grounds and stable genetic diversity.
Article
Fisheries
Richard McGarvey, Mike A. Steer, Jonathan J. Smart, Damian J. Matthews, Janet M. Matthews
Summary: This study extends the DEPM method to explicitly consider the size structure of female fish, estimating total spawning biomass, female population numbers by weight class, and batch fecundity. By fitting the allometric dependence of batch fecundity on female body weight, this size-based DEPM approach can provide valuable information for fishery management decision making.
FISHERIES RESEARCH
(2021)
Article
Fisheries
Warwick H. Sauer, Ian G. Gleadall, Nicola Downey-Breedt, Zoe Doubleday, Graham Gillespie, Manuel Haimovici, Christian M. Ibanez, Oleg N. Katugin, Stephen Leporati, Marek Lipinski, Unai Markaida, Jorge E. Ramos, Rui Rosa, Roger Villanueva, Juan Arguelles, Felipe A. Briceno, Sergio A. Carrasco, Leo J. Che, Chih-Shin Chen, Rosario Cisneros, Elizabeth Conners, Augusto C. Crespi-Abril, Vladimir V. Kulik, Evgenyi N. Drobyazin, Timothy Emery, Fernando A. Fernandez-Alvarez, Hidetaka Furuya, Leo W. Gonzalez, Charlie Gough, P. Krishnan, Biju Kumar, Tatiana Leite, Chung-Cheng Lu, Kolliyil S. Mohamed, Jaruwat Nabhitabhata, Kyosei Noro, Jinda Petchkamnerd, Delta Putra, Steve Rocliffe, K. K. Sajikumar, Hideo Sakaguchi, Deepak Samuel, Geetha Sasikumar, Toshifumi Wada, Xiaodong Zhen, Yongjun Tian, Yumeng Pang, Anyanee Yamrungrueng
Summary: Recent studies have shown a global increase in coastal and shelf cephalopod populations, with octopus production steadily rising over the past three decades. Octopus fisheries are expected to continue growing in importance due to the overexploitation of many finfish stocks, and there is a need for effective management and conservation measures to protect cephalopod resources.
REVIEWS IN FISHERIES SCIENCE & AQUACULTURE
(2021)
Article
Fisheries
Niall J. McKeown, Michael P. Gwilliam, Amy J. E. Healey, Ilze Skujina, Warren M. Potts, Warwick H. H. Sauer, Paul W. Shaw
JOURNAL OF FISH BIOLOGY
(2020)
Article
Oceanography
Willem Malherbe, Warwick Sauer, Shankar Aswani
OCEAN & COASTAL MANAGEMENT
(2020)
Article
Environmental Sciences
Zoe L. Jacobs, Fatma Jebri, Meric Srokosz, Dionysios E. Raitsos, Stuart C. Painter, Francesco Nencioli, Kennedy Osuka, Melita Samoilys, Warwick Sauer, Michael Roberts, Sarah F. W. Taylor, Lucy Scott, Hellen Kizenga, Ekaterina Popova
Review
Fisheries
Hassan Moustahfid, Lisa C. Hendrickson, Alexander Arkhipkin, Graham J. Pierce, Avijit Gangopadhyay, Hideaki Kidokoro, Unai Markaida, Chingiz Nigmatullin, Warwick H. Sauer, Patrizia Jereb, Gretta Pecl, Thibaut de la Chesnais, Luca Ceriola, Najih Lazar, Christopher J. Firmin, Vladimir Laptikhovsky
Summary: Cephalopods have significant economic importance globally, but the fluctuation in their population poses challenges for fishers and managers, mainly due to the lack of a forecasting system for squid fisheries. Despite progress in relating environmental change to squid population dynamics, more challenges need to be overcome in the future to develop forecast products for sustainable squid fisheries management.
REVIEWS IN FISHERIES SCIENCE & AQUACULTURE
(2021)
Article
Ecology
Yoko Iwata, Noriyosi Sato, Noritaka Hirohashi, Yoshiro Watanabe, Warwick H. H. Sauer, Paul W. Shaw
Summary: The study found that different mating tactics in squid species can affect the quantitative and qualitative traits of male sperm, and the female's sperm storage mode and fertilization processes are important factors influencing this evolution; unlike consort males, sneaker males are more likely to face sperm competition risks; through adjustment of sperm packaging, different levels of sperm competition risk can be adapted to.
JOURNAL OF EVOLUTIONARY BIOLOGY
(2021)
Article
Oceanography
Z. L. Jacobs, A. Yool, F. Jebri, M. Srokosz, S. van Gennip, S. J. Kelly, M. Roberts, W. Sauer, A. M. Queiros, K. E. Osuka, M. Samoilys, A. E. Becker, E. Popova
Summary: The study highlights the importance of understanding potential impacts of future climate change on marine ecosystems in the countries bordering the tropical Western Indian Ocean. Using a high-resolution ocean model, the research identifies key regionally important climate change stressors over the East African Coastal Current and underscores the need for regional monitoring systems and investment in decadal prediction methods.
OCEAN & COASTAL MANAGEMENT
(2021)
Article
Environmental Sciences
Kelly Ortega-Cisneros, Kevern L. Cochrane, Nina Rivers, Warwick H. H. Sauer
Summary: The marine fisheries sector in South Africa is important for income and food security, but documents related to fisheries management rarely address climate change impacts and adaptation. There is a need for more explicit inclusion of information on climate change impacts and adaptation in order to ensure the sector can effectively adapt to climate change.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Fatma Jebri, Dionysios E. Raitsos, John A. Gittings, Zoe L. Jacobs, Meric Srokosz, Jessica Gornall, Warwick H. H. Sauer, Michael J. Roberts, Ekaterina Popova
Summary: Using satellite observations, this study uncovers the biophysical drivers of the lucrative chokka squid fishery in South Africa over the last two decades (1998-2017) and addresses their potential links with low squid catches. Chokka squid fishing is crucial to the economic wellbeing of local communities. However, the squid biomass is prone to considerable fluctuations, including abrupt declines with negative socio-economic impacts. These results show that the squid catch fluctuations are potentially predictable and could support policymakers seeking to improve their planning of adaptation strategies and risk mitigation.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Oceanography
Robert J. Wilson, Sevrine F. Sailley, Zoe L. Jacobs, Joseph Kamau, Said Mgeleka, Gladys M. Okemwa, Johnstone O. Omukoto, Kennedy E. Osuka, Melita Samoilys, Warwick Sauer, Mathew Ogalo Silas, Joseph S. Sululu, Michael J. Roberts
Summary: The study predicts significant reduction in fish biomass in Kenyan and Tanzanian Exclusive Economic Zones under the impact of climate change during the 21st Century, especially for tunas. Increasing fishing pressure is expected to exacerbate the decline in fish biomass.
OCEAN & COASTAL MANAGEMENT
(2021)
Article
Oceanography
Sarah Asdar, Zoe L. Jacobs, Ekaterina Popova, Margaux Noyon, Warwick H. Sauer, Michael J. Roberts
Summary: Climate change poses significant threats to the Agulhas Bank fishery, particularly the chokka squid fishery. Our simulations show that increased sea surface temperature and current velocity may pose risks to squid recruitment and growth, while food availability is expected to have a minor impact.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Oceanography
Zoe Jacobs, Mike Roberts, Fatma Jebri, Meric Srokosz, Stephen Kelly, Warwick Sauer, Jorn Bruggeman, Ekaterina Popova
Summary: The Agulhas Bank, off the coast of South Africa, is a vital area for fisheries due to its complex biophysical mechanisms. The presence of the "cold ridge" plays a crucial role in the productivity of the area and potentially impacts the recruitment of important species such as squid.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2022)
Article
Fisheries
Steven J. Cooke, Elizabeth A. Fulton, Warwick H. H. Sauer, Abigail J. Lynch, Jason S. Link, Aaron A. Koning, Joykrushna Jena, Luiz G. M. Silva, Alison J. King, Rachel Kelly, Matthew Osborne, Julia Nakamura, Ann L. Preece, Atsushi Hagiwara, Kerstin Forsberg, Julie B. Kellner, Ilaria Coscia, Sarah Helyar, Manuel Barange, Elizabeth Nyboer, Meryl J. Williams, Ratana Chuenpagdee, Gavin A. Begg, Bronwyn M. Gillanders
Summary: A common goal among fisheries science professionals, stakeholders, and rights holders is to ensure the persistence and resilience of vibrant fish populations and sustainable, equitable fisheries in diverse aquatic ecosystems. The World Fisheries Congress (WFC) provides a global forum to discuss threats, issues, and opportunities facing fish populations and fisheries. The 2021 WFC meeting reflects on progress made in the past 30 years and identifies future needs and opportunities to improve sustainability in the world's fisheries.
REVIEWS IN FISH BIOLOGY AND FISHERIES
(2023)
Article
Marine & Freshwater Biology
J. M. Eggers, K. L. Cochrane, W. H. H. Sauer
Summary: This study analyzed the trends in income and employment opportunities of the west coast rock lobster fishery in South Africa. The fishery was found to contribute to the gross national income, but decreasing quotas had a negative effect on some representative individuals. The study suggests that a more extensive understanding of the socio-economic context of the fishery is needed for effective resource recovery and equitable distribution of fishing opportunities.
AFRICAN JOURNAL OF MARINE SCIENCE
(2022)
Article
Marine & Freshwater Biology
M. R. Lipinski, M. A. Mmethi, D. Yemane, J. Githaiga-Mwicigi, W. H. H. Sauer
Summary: Temporal trends in size composition and length-weight relationship of chokka squid on the south coast of South Africa were examined over a 22-year period. While no significant long-term changes were observed in mean lengths, there was a short-term drop in average length in certain years, possibly linked to the introduction of an additional closed season. Parameters of the length-weight relationship remained stable over the years, with males showing a higher prevalence of starvation compared to females, potentially due to spawning behavior.
AFRICAN JOURNAL OF MARINE SCIENCE
(2021)