Latent Gaussian models to predict historical bycatch in commercial fishery

Breivik, Olav Nikolai; Storvik, Geir; Nedreaas, Kjell Harald

doi:10.1016/j.fishres.2016.09.033

Cited by 12 publications

(12 citation statements)

References 17 publications

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“…Factoring in incidental bycatch (e.g., Ianelli and Stram, 2014;Breivik et al, 2017) and the effects of trawling (represented by Stern Trawlers and Factory Stern Trawlers in this study; Table 3) on demersal communities (Puig et al, 2012;Christiansen et al, 2014), impacts on ecosystem integrity from this industry are indeed consequential. Effects on targeted species assemblages themselves and related ecosystem impacts compound negative influences on these biological communities (Zeller et al, 2011;ICES, 2018;Popov and Zeller, 2018).…”

Section: Impacts From Fisheriesmentioning

confidence: 82%

Vessel Operations in the Arctic, 2015–2017

Silber¹,

Adams

2019

Front. Mar. Sci.

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The Arctic is among the most rapidly-changing regions on Earth. Diminishing levels of sea-ice has increased opportunities for maritime activities in historically inaccessible areas such as the Northern Sea Route and Northwest Passage. Degradation of Arctic marine ecosystems may accompany expanding vessel operations through introduced underwater noise, potential for large oil spills, among other things; and may compound stressors already effecting biological populations due to climate change. Assessments are needed to track changes in vessel traffic patterns and associated environmental impacts. We analyzed Arctic-wide vessel Automatic Identification System data 1 January 2015 to 31 December 2017 to quantify the amount and spatial distribution of vessel operations, assess possible changes in these operations, and establish a baseline for future monitoring. Nearly 400,000 vessel transits were analyzed. Number of trips, hours of operation, and amount of sea surface exposed to vessel traffic were used to compare operations between 14 delineated waterways. Operations were extensive and diverse: an average of 132,828 trips were made annually by over 5,000 different vessels. Transits were made in all areas studied and all months of the year. Maritime activities were intensive in some areas, but ice-limited in others. Amount of sea surface exposed to vessel traffic exceeded 70% in all but three areas. Bulk carriers, cargo ships, passenger/cruise ships, research survey ships, and vessels supporting oil/gas-related activities were represented. However, fishing vessels, primarily in the Barents, Bering, and Norwegian Seas, surpassed operations of all other vessel types and comprised about one-half of all voyages each year. We observed no overt increasing or decreasing trends in vessel traffic volume in our limited study period. Instead, inter-year variation was evident. While the number of unique vessels and transits increased year-to-year, hours of operation declined in the same period. Abundance/distribution of fisheries resources, economic feasibility of Arctic marine travel as weighed against inherent risks, and other factors likely accounted for inter-year variation in regional activity levels. Measures have been established to protect Arctic marine ecosystems but may need strengthening to address potential ecosystem threats from existing and growing commercial and industrial activities in the region.

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Section: Impacts From Fisheriesmentioning

confidence: 82%

Vessel Operations in the Arctic, 2015–2017

Silber¹,

Adams

2019

Front. Mar. Sci.

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“…An estimation of total retained catches in the Norwegian Economic Zone by Aanes et al (2011) used Coast Guard inspections, stating that vessel selection is based solely upon the proximity to the pre-defined patrol route. Passive sampling by the MSS was used as the primary data source for the prediction of historical cod bycatch in the Barents Sea shrimp fishery (Breivik et al 2017). Potential observer effects were deemed to be negligible due to the nature of the monitoring programme, but they did highlight that such assumptions should be reconsidered if the method is transferred to other fisheries.…”

Section: Enforcement and Surveillance Samplingmentioning

confidence: 99%

“…However, over the last two decades there have been advances in techniques for dealing with complexities such as clustered sampling (Harrison et al 2018), low encounter rates (Martin et al 2005), spatial-temporal correlation (Rue and Martino 2009) and their extensions to multispecies estimations (Thorson et al 2017). The appropriate application of these methods can result in reduced bias (Breivik et al 2017) or improved precision (Stock et al 2018). These methods have also seen improved computation times and more opensource support, making them more accessible to fisheries studies.…”

Section: Design-and Model-based Approachesmentioning

confidence: 99%

“…There was previously an argument for considering the computation time of complex models. However, with advancements in computing power and software development, such run times are now measured in hours or minutes (Rue and Martino 2009;Cosandey-Godin et al 2014;Breivik et al 2017).…”

Section: Zero-inflated Modelling Techniquesmentioning

confidence: 99%

“…Other estimates of discards and unreported catches in Norway (Dingsør 2001a;Valdemarsen and Nakken 2002) indicate low levels of discarding relative to the global average (Pérez Roda et al 2019), whilst numerous studies have provided snapshot estimates for individual fisheries (e.g. Hylen and Jacobsen 1987;McBride and Fotland 1996;Dingsør 2001b;Breivik et al 2017). The available estimates, both nationally and for individual fisheries, have been constrained by a lack of at-sea observations throughout time, focussing on shorter timescales and specific fisheries where data are available.…”

Section: Introductionmentioning

confidence: 99%

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Applying global best practices for estimating unreported catches in Norwegian fisheries under a discard ban

Clegg

Kennelly

Blom

et al. 2020

Rev Fish Biol Fisheries

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In addition to their role as a fisheries management tool, discard bans can be effective in improving knowledge of total catches via the requirement to land and report all catches. This shifts the focus to understanding the scale of unreported catches in fisheries, rather than only on discards. However, the presence of a discard ban can cause problems with estimation process, as it involves the observation of illegal activities, and the complex sources of unreported catches require a different approach to estimation. The Norwegian discard ban was introduced in 1987 as part of a wider suite of regulatory measures to improve exploitation patterns in commercial fisheries, but a framework for the regular estimation of unreported catches has yet to be established and operationalised. Here, we aim to identify global best practices for estimating unreported catches under a discard ban and assess their applicability to Norwegian fisheries. We approach this in three steps: (1) defining the scope of an estimation, (2) data collection, and (3) the actual procedure for estimation. We discuss how each step can affect the quality of an estimate with regards to accuracy, precision, practical limitations and whether the estimate is fit for purpose. Finally, we provide a list of recommendations for future studies and identify key knowledge gaps and limitations regarding their application to Norwegian fisheries.

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Ecosystem approach to harvesting in the Arctic: Walking the tightrope between exploitation and conservation in the Barents Sea

Heath

Benkort

Brierley

et al. 2021

Ambio

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Projecting the consequences of warming and sea-ice loss for Arctic marine food web and fisheries is challenging due to the intricate relationships between biology and ice. We used StrathE2EPolar, an end-to-end (microbes-to-megafauna) food web model incorporating ice-dependencies to simulate climate-fisheries interactions in the Barents Sea. The model was driven by output from the NEMO-MEDUSA earth system model, assuming RCP 8.5 atmospheric forcing. The Barents Sea was projected to be > 95% ice-free all year-round by the 2040s compared to > 50% in the 2010s, and approximately 2 °C warmer. Fisheries management reference points (FMSY and BMSY) for demersal fish (cod, haddock) were projected to increase by around 6%, indicating higher productivity. However, planktivorous fish (capelin, herring) reference points were projected to decrease by 15%, and upper trophic levels (birds, mammals) were strongly sensitive to planktivorous fish harvesting. The results indicate difficult trade-offs ahead, between harvesting and conservation of ecosystem structure and function.

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Latent Gaussian models to predict historical bycatch in commercial fishery

Cited by 12 publications

References 17 publications

Vessel Operations in the Arctic, 2015–2017

Vessel Operations in the Arctic, 2015–2017

Applying global best practices for estimating unreported catches in Norwegian fisheries under a discard ban

Ecosystem approach to harvesting in the Arctic: Walking the tightrope between exploitation and conservation in the Barents Sea

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