ICES Journal of Marine Science: Journal du Conseil

McInturf, A G; Bowman, J; Schulte, J M; Newton, K C; Vigil, B; Honig, M; Pelletier, S; Cox, N; Lester, O; Cantor, M; Chapple, T K

doi: 10.1093/icesjms/fsad099pmid: N/A

Elasmobranchs are highly diverse in movement, sensory capacity, and behavioural responses to the environment, leading to differences in the function and nature of associations and interactions between individuals, populations, and species. The term “aggregation” has been widely and variably used to describe co-occurrence across elasmobranch species, but its defining criteria remain vague and indeterminate. The lack of standardized terminology hinders comparisons across studies, species, and systems. It can cause misinterpretation about the drivers of aggregation formation or grouping behaviour and limits the impact of elasmobranch behavioural research. Here, we propose generalizable definitions of aggregation and supporting terms, adapted from more mature socioecological theory in other systems, which can be applied across elasmobranchs. We discuss the drivers and types of elasmobranch aggregations, detail the criteria required to identify an aggregation based on our definition, and offer direction on future methods and reporting to advance the field. These proposed definitions and reporting protocols standardize the study of elasmobranch socioecology, will generate greater understanding of the mechanisms underlying behaviour and distribution across species, and support more cross-system comparisons. Finally, this information can offer greater predictive power into when and how aggregations may form, leading to more proactive management strategies to mitigate anthropogenic threats.

Hilborn, R; Amoroso, R; Collie, J; Hiddink, J G; Kaiser, M J; Mazor, T; McConnaughey, R A; Parma, A M; Pitcher, C R; Sciberras, M; Suuronen, P

doi: 10.1093/icesjms/fsad115pmid: N/A

Mobile bottom contact gear such as trawls is widely considered to have the highest environmental impact of commonly used fishing gears, with concern about impact on benthic communities, bycatch, and carbon footprint frequently highlighted as much higher than other forms of fishing. As a result, the use of such gears has been banned or severely restricted in some countries, and there are many proposals to implement such restrictions elsewhere. In this paper, we review the sustainability of bottom trawling with respect to target-species sustainability, impact on benthic communities, bycatch and discards, carbon footprint from fuel use, and impact on carbon sequestration. We compare the impact to other forms of fishing and other food production systems. We show that bottom-trawl and dredge fisheries have been sustained, and where well managed, stocks are increasing. Benthic sedimentary habitats remain in good condition where fishing pressure is well managed and where VME and species of concern can be protected by spatial management. Bycatch is intrinsically high because of the mixed-species nature of benthic communities. The carbon footprint is on average higher than chicken or pork, but much less than beef, and can be much lower than chicken or pork. The impact on carbon sequestration remains highly uncertain. Overall, the concerns about trawling impacts can be significantly mitigated when existing technical gear and management measures (e.g. gear design changes and spatial controls) are adopted by industry and regulatory bodies and the race-to-fish eliminated. When these management measures are implemented, it appears that bottom trawling would have a lower environmental impact than livestock or fed aquaculture, which would likely replace trawl-caught fish if trawling was banned. A total of 83 bottom-trawl fisheries are currently certified by the Marine Stewardship Council, which is the most widely accepted measure of overall sustainability.

Kressler, Molly M; Dall, Sasha R X; Sherley, Richard B

doi: 10.1093/icesjms/fsad082pmid: N/A

Historic limitations have resulted in marine ecological studies usually overlooking some well-established concepts from behavioural ecology. This is likely because the methods available were easily overwhelmed by the scale of ecological processes and sampling resolution in the marine environment. Innovations in technology, data management, and statistical modelling now provide the capacity to fully embrace behavioural ecology concepts and study marine ecological interactions from a more holistic perspective. To facilitate this vision, we propose a novel perspective and workflow for marine ecology: the Seascape of Ecological Energy, or SEE-scapes. SEE-scapes contextualizes the accumulated knowledge from marine biology and behavioural ecology research and provides a guide for marine scientists interested in grounding their research in behavioural ecology’s first principles. SEE-scapes specifies relevant considerations for contemporary seascapes, with special attention to relationships between individuals and their conspecifics, competitors, predators, and the abiotic environment. It is formulated to account for how the unique features of marine vertebrates require revisions to standard, terrestrially focused methodological approaches, and offers solutions for how to sample and model the eco-evolutionary drivers of behaviour across the dynamic and hierarchical seascape. Simply put, SEE-scapes provides the guidance to translate a dynamic system and reveal opportunities for collaborative and integrative research.

Ohayon, Sarah; Homma, Hikaru; Malamud, Shahar; Ostrovsky, Ilia; Yahel, Ruthy; Mehner, Thomas; Kanari, Mor; Belmaker, Jonathan

doi: 10.1093/icesjms/fsad086pmid: N/A

Because marine protected areas (MPAs) are not equally effective across their areas, monitoring should progress from dichotomic (within vs. outside) to a finer spatial resolution. Here, we examine the effect of an Eastern Mediterranean no-take MPA on fishes across the MPA and into fished areas, using three methods: underwater visual censuses, acoustic surveys, and towed-diver surveys. The Eastern Mediterranean includes non-indigenous species, so the effect of the MPA was also evaluated for its resistance to invasion. The fine-scale analysis revealed ecological phenomena that could not be captured by dichotomic sampling, such as the edge effect, a reduction of fish biomass along the MPA periphery. Despite their differences, all three methods revealed similar spatial patterns. The fine-scale analysis did not support a biotic resistance of the MPA to non-indigenous species. Our study supports the prevalence of edge effects even in well-enforced no-take MPAs and highlights the need for continuous monitoring to reveal these patterns.

de Pontual, Helene; Heerah, Karine; Goossens, Jolien; Garren, François; Martin, Stephane; Le Ru, Loic; Le Roy, Didier; Woillez, Mathieu

doi: 10.1093/icesjms/fsad087pmid: N/A

Large-scale electronic tagging is a very powerful tool to study how fish movements and migrations shape the internal dynamics of populations. This knowledge, crucial for improving fishery management, was still limited for the European seabass, whose stocks in the Northeast Atlantic have declined drastically over the last decade. To better understand the species ecology and the spatio-temporal structure of the population, we tagged seabass in the North Sea, the English Channel, and the Bay of Biscay, from 2014 to 2016. Out of 1220 deployed DSTs, 482 have been recovered by November 2022. Approximately half of them included a period of potential spawning migration. Reconstructed trajectories confirmed seabass to be a partial migratory species, as individuals exhibited either long-distance migrations or residence. Most migrants exhibited fidelity to summer feeding areas and winter spawning areas. Our dataset enriches the knowledge of seabass biological traits (e.g. temperature and depth ranges, vulnerability to predation and fishing). Our results suggest a spatial structure of the Atlantic population that differs from the stock structure currently considered for assessment and management. The consequences should be explored at both the European level and by regional managers involved in conservation outcomes.

Barnhill, Kelsey Archer; Vinha, Beatriz; Smith, Alycia J; de Jonge, Daniëlle S W; Gaurisas, Daniela Y; Segura, Roger Mocholí; Madureira, Pedro; Albuquerque, Mónica; Huvenne, Veerle A I; Orejas, Covadonga; Gunn, Vikki

doi: 10.1093/icesjms/fsad088pmid: N/A

Sailing on scientific expeditions as an early career researcher (ECR) offers the beneficial opportunity to gain field experience and training. However, the number of available berths to achieve the scientific goals of an expedition limits the number of onboard participants. Telepresence and remote learning can be utilized to increase the number of active participants, broadening the reach of capacity development. The 2021 iMirabilis2 expedition on board the Spanish Research Vessel Sarmiento de Gamboa used telepresence to virtually involve ECRs from several countries in deep-sea science. One year post-expedition, a survey of onshore participants was conducted to assess and quantify the effectiveness of the peer-to-peer ECR ship-to-shore scheme. During the expedition, live, interactive training via WhatsApp and Zoom was utilized by onshore ECRs more than traditional static, unidirectional methods of blog posts and pre-recorded videos. All respondents either agreed or strongly agreed that the scheme provided an inclusive and accessible platform to share deep-sea science. These results suggest similar schemes could be used to supplement shorter-duration at-sea-training, used prior to a seagoing experience to better prepare ECRs, or to allow members of the science community unable to join an expedition in person to actively participate remotely, increasing inclusivity.

Blondin, H E; Haulsee, D E; Logan, R; Shivji, M; Hoffmayer, E R; Walker, J H; Dean, J M; Hazen, E L; Crowder, L B

doi: 10.1093/icesjms/fsad090pmid: N/A

Blue marlin (Makaira nigricans) and sailfish (Istiophorus platypterus) are ecologically important predators and valuable species throughout the world’s recreational, commercial, and subsistence fisheries. Comparing multi-species vertical habitat use can inform ecological uncertainties such as inter-species competition, as well as relative vulnerabilities to fishing activities. In this study, we identified key differences in both depth use and which environmental variables drive these selections, which highlights the variability in the catchability both as target species in recreational fisheries and bycatch in commercial fisheries. To understand these two species’ vertical habitat use, we examined depth profiles from 26 sailfish and 48 blue marlin tagged with pop-up satellite archival tags deployed in the Eastern Tropical Pacific Ocean. While both species are surface-oriented, we found evidence of vertical niche partitioning where sailfish spend more time at deeper depths than blue marlin. Blue marlin recorded an average mean depth of 18.5 m (±10.8 m) during daytime and 5.2 m (±5.5 m) at nighttime (Figure 31a), while sailfish recorded an average mean depth of 23.6 m (±11.1 m) during daytime and 6.45 m (±4.64 m) at nighttime. Generalized additive mixed models fitted to predict mean and max depth revealed sea level anomaly (SLA), oxygen, sea surface temperature, and mixed layer depth as significant predictors of vertical habitat use for both species. We also examined catch logs from three recreational fishing lodges in Central America to understand the influence of environmental conditions on billfish sightings per unit effort. For blue marlin and sailfish, SLA was a significant predictor in each of the four depth models (mean day, mean night, max day, max night). SLA was the variable with highest percent deviance explained for all four sailfish depth models and three of the four blue marlin depth models and had a positive relationship with all response variables for all four blue marlin depth models and three sailfish depth models (mean daytime, max daytime, max nighttime), where higher positive SLA values were associated with deeper depth responses.

Kanaji, Y; Sasaki, H; Hakamada, T; Okamura, H

doi: 10.1093/icesjms/fsad091pmid: N/A

An assessment of the abundances and their trends is urgently needed for the conservation and management of fishery-targeted and rarely seen cetacean species (FTCS and RSCS, respectively); however, such assessment is often challenging because of the paucity of available data. In particular, the number of sightings is smaller than the general requirement for the reliable estimation of a detection function, and the spatial coverage of many cetacean surveys is insufficient. To address these issues, we propose a Bayesian approach that uses the previous abundance estimation of the same species or a species with similar biological traits as prior information. Therefore, we obtained the latest abundance estimates for six FTCS and two RSCS. For FTCS, we also estimated abundance trends by fitting an exponential population dynamics model with random effects accounting for interannual changes in animal distributions to the posterior samples of the Bayesian abundance estimates. Our approach enables us to (1) facilitate stakeholders’ consensus by maintaining previously agreed abundances while updating the conservation information; (2) identify the species of greater concern and prioritize conservation efforts towards those species; and (3) monitor the abundance and trends of data-limited cetacean species.

Sales Henriques, Nuno; Russo, Tommaso; Bentes, Luis; Monteiro, Pedro; Parisi, Antonio; Magno, Ramiro; Oliveira, Frederico; Erzini, Karim; Gonçalves, Jorge M S

doi: 10.1093/icesjms/fsad092pmid: N/A

The use of tracking devices, such as vessel monitoring systems or automatic identification system, enabled us to expand our knowledge on the distribution and quantification of fishing activities. However, methods and models based on vessel tracking data are mostly devised to be applied to towed gears, whereas applications to multi-gear and passive fisheries have been underrepresented. Here, we propose a methodology to deal with geospatial data to map and quantify the fishing effort, as soak time, of passive fishing gears used by a multi-gear fishing fleet. This approach can be adapted to other passive multi-or single-gear fisheries, since it requires only three variables that can be extracted from a pre-classified dataset, to identify the beginning (gear deployment) and the end (hauling) of passive fishing events. As far as we are aware, this is the first time a methodology that allows quantifying the soak time of static passive fishing events, within a polyvalent fishery context, is presented. We argue that the information that can be extracted from such approaches could contribute to improved management of multi-gear and static-gear fisheries and the ecosystem-based approach.

Clarke, Thomas M; Whitmarsh, Sasha K; Champion, Curtis; Pederson, Hugh; Meyer, Lauren; Dennis, Joshua D; Dwyer, Ross G; Huveneers, Charlie

doi: 10.1093/icesjms/fsad093pmid: N/A

Wildlife tourism can have adverse effects on the behaviours and movements of animals, with implications for the health and fitness of individuals and populations. We used acoustic-tracking to show that food-based attractants used in shark-tourism increases activity (15%) and burst behaviours (60%) in yellowtail kingfish (Seriola lalandi, n = 18). Increased activity was restricted to periods when kingfish were on the same side of the island group as berleying tourism vessels, but decreased after operators left the site. Despite the raised activity and frequency of burst swimming events, the physiological condition of kingfish (n = 39, 6 tagged, and 33 untagged) measured using bioelectrical impedance analysis remained consistent with kingfish from control sites not exposed to tourism. This suggests that kingfish were able to compensate raised energy expenditure by feeding on bait and berley used by operators or through natural foraging. We highlight that the effects of provisioning from wildlife tourism can extend beyond changes in behaviours and movements and can additionally influence the energetic condition of non-focal animals through increased activity. However, supplemental food-sources provided through wildlife tourism may be sufficient to compensate for the increased energy expenditure and lessen the effects of tourism on individual fitness and health.