Agenda
13:00
Introduction to core team, seminar series, and SIIECS
Marta Ferraro
Presentations followed by feedback sessions
13:15
Unlocking eel movement: A lake-specific traceability tool for the conservation and management of anguilla anguilla in the shannon catchment
Competitive angling as a scientific tool: generating long term population data to support ecosystem-based management of coastal fisheries
Presentation summaries for this event
Varying natural mortality and density-dependence: consequences for HCR sensitivity in a small pelagic species
Ignoring or oversimplifying important processes that determine stock dynamics, notably natural mortality and density-dependence, may increase the risk of inadequate fisheries management, as it can mean overlooking important population fluctuations. Here, we tested the sensitivity of the currently used ICES harvest control rule (current HCR) for Norwegian spring-spawning herring (NSS herring) under alternative population models using a short-cut management strategy evaluation (MSE). We configured a base scenario with age-dependent natural mortality (SCbase) similarly to the ICES MSE for NSS herring. The alternative population scenarios included (a) density-dependent growth and maturity (SC1), included in most alternative population scenarios; (b) random-walk natural (SC2); (c) increasing trend in natural mortality over 30 years (SC3); (d) length-based natural mortality (SC4); (e) indirect density-dependent effect in length-based natural mortality (SC5); and (f) direct density-dependent effect in age-based natural mortality (SC6). A grid of possible HCR control parameters (Ftarget and Btrigger) was tested for each scenario. Performance was evaluated according to risk of SSB falling below an absolute Blim and relative Blim values based on the pristine biomass per scenario alongside interannual variability (IAV) in median catch and median catch. Results show that the current HCR is sensitive to the added biological complexity, particularly an increasing rate of natural mortality. However, the level of risk depends on the definition of Blim. A lower Ftarget and a higher Btrigger demonstrated lower risk without compromising catch compared to the current HCR across most population scenarios. Shortcut MSEs offer a more efficient initial exploration of sustainable long-term management of various population scenarios against several HCRs, facilitating a more comprehensive evaluation of management performance before conducting a full MSE.
Keywords: natural mortality, density-dependence, harvest control rules, MSE
Bio: I am a PhD student and a member of SIIECS. My work focuses on marine fisheries science and management.
Unlocking eel movement: A lake-specific traceability tool for the conservation and management of anguilla anguilla in the shannon catchment
The River Shannon is the largest river system in Ireland, covering an area of 11,700 km2. The Shannon catchment is composed of many large lakes, with the top 14 lakes having a combined area of >366km2. The system is important as a habitat for the endangered European eel (Anguilla anguilla) which has undergone a 90% decline in abundance since the mid-1980s. As part of the National Eel Management Plan in Ireland, large numbers of elvers (young eels migrating upstream) are trapped and transported around the dam at Ardnacrusha, located at the bottom of the catchment. Identifying which of 14 major lakes in the Shannon catchment provides the best habitat for adult eel production is vital to conservation efforts of this species. This study aims to develop a lake-specific traceability tool using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) to determine the Trace Elemental Fingerprints (TEFs) of eel otoliths and flesh. To assess the relative importance of each Shannon lough to the migratory stage of the A. anguilla population; the TEF data will be subjected to an ensemble modelling approach using machine learning methods, including Random Forest, Gradient Boosting, and Extra Tree. Understanding the contribution of each of the lakes to the adult spawners migrating from the catchment to their spawning grounds in the Sargasso Sea, we aim to inform fishery managers of the optimum locations to transport elvers to maximise the connectivity of this critically endangered catadromous species’ spawning and rearing locations.
Keywords: trace elements, eels, connectivity, traceability
Bio: I am a PhD student at the Marine and Freshwater Research Centre since February 2023. My Project aims to develop methods of traceability within the Irish seafood industry, using trace elements in combination with machine learning techniques.
Competitive angling as a scientific tool: generating long term population data to support ecosystem-based management of coastal fisheries
Coastal fisheries are economically important, but in order to make evidence-based management decisions, data are key. However, for many targeted fish species in the UK, data is limited. The challenge in collecting sufficient fisheries-relevant data is the significant investment of people, time, and money so a popular strategy is the use of citizen scientists. We utilise data collated from the Sea Angling Classic in the Solent, UK. Up to 100 teams in this two-day event target five groups to compete for a significant monetary prize. Since 2021 over 2000 geolocated images have been collated generating length measurements of five data deficient, but economically important groups (European seabass, Black bream, skates and rays, Smoothhound and Tope. In addition, DNA swabs of species that are hard to identify (e.g. Raja spp.) or commonly misidentified (e.g. Mustelus spp.) were also collected by trained observers. Although there are currently temporal limitations of our 3-year dataset, the development of a standardised workflow combined with automated AI-driven morphometric, catch-per-unit-effort and species identification methods will provide a powerful, cost-effective approach for generating scientific evidence. These data will inform ecosystem-based fisheries policies in the UK, but the methods can equally be applied to competitive angling events globally.
Keywords: citizen science, competitive angling, fisheries management, coastal fisheries
Bio: I studied Biological Sciences at The University of Oxford (MA) and Applied Aquatic Biology at Portsmouth University (MSc). I am married to a serving Royal Naval Officer and took a career break following graduation to travel, support his career, and start a family. I've recently returned to my career and have been working at the University of Portsmouth since January 2023 as a Research Associate.
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