ICES Journal of Marine Science

Dolan, John R

doi: 10.1093/icesjms/fsaf041pmid: N/A

Einer Steemann Nielsen’s 1952 methods paper describing the use of C14 to measure photosynthesis in the journal now known as the ICES Journal of Marine Research was a landmark publication. It is still regularly cited today. Here, in a brief account, the story of Einer Steemann Nielsen (1907–1989), and his major publication is given, along with evidence of its enduring value.

Clark, Zach S R; Miller, Adam D; Sherman, Craig D H; Morris, Stephen; Weeks, Andrew R; Butcher, Paul A

doi: 10.1093/icesjms/fsaf043pmid: N/A

Bather protection programmes rely heavily on surveillance tools capable of detecting the presence of shark species that are known to physically interact with humans. This study investigates the potential for environmental DNA (eDNA) technologies to improve shark detection capabilities and complement current survey methods. We conducted a 14-month monitoring programme at two white shark (Carcharodon carcharias) visitation hotspots in eastern Australia and assessed spatio-temporal patterns of near-shore visitation using a species-specific eDNA assay, SMART (Shark-Management-Alert-in-Real-Time) drumline captures, and acoustic telemetry data from tagged white sharks. We observed higher shark detection frequencies across both survey locations using eDNA compared to the SMART drumline and telemetry survey methods. Specifically, eDNA surveys provided relatively constant rates of detection across the survey period, whereas SMART drumline and telemetry detections were highly seasonal and largely restricted to the austral winter–spring period. Findings from the eDNA surveys are consistent with current assumptions about white shark spatial ecology with year-long presence of white sharks in near-shore subtropical habitats in eastern Australia but suggest that shark presence during the summer–autumn months is possibly more prevalent than currently assumed. Overall, this study highlights the value of eDNA as a tool for enhancing shark detection capabilities, and the importance of adopting multiple complementary survey methods when assessing shark visitation rates. We discuss the implications of these findings for bather protection and white shark mitigation programmes in Australia and overseas.

Dunic, Jillian C; Conner, Jason; Anderson, Sean C; Thorson, James T

doi: 10.1093/icesjms/fsaf040pmid: N/A

Fisheries scientists use regression models to estimate population quantities, such as biomass or abundance, for use in climate, habitat, stock, and ecosystem assessments. However, these models are sensitive to the probability distribution used to characterize observation error. Here, we introduce the generalized gamma distribution (GGD), which has not been widely used in fisheries science. The GGD has useful properties: (1) it reduces to the lognormal distribution when the shape parameter approaches zero, (2) it reduces to the gamma distribution when the shape and scale parameters are equal, and (3) the coefficient of variation is independent of the mean. We assess the relative performance and robustness of the GGD to estimate biomass density across different observation error types in a simulation experiment. When fit to data generated from the GGD, lognormal, gamma, and Tweedie families, the GGD had low bias, high predictive accuracy, and appropriate confidence interval coverage under most scenarios. Finally, we fit spatiotemporal index standardization models using the R package sdmTMB to 14 species from three trawl surveys from the Gulf of Alaska and coast of British Columbia, Canada. When the Akaike information criterion weight was compared among fits using the lognormal, gamma, and Tweedie families, the GGD was the most commonly selected model. When compared via cross validation, predictive performance favoured the GGD for most (75%) Gulf of Alaska species but was less clear for the smaller British Columbia surveys. We conclude that the GGD is a flexible and effective choice for modelling fisheries-independent survey data, offering several advantages over commonly used distributions. Given its strong performance in both simulation and empirical analyses, we recommend that practitioners consider the GGD when selecting error distributions for these models.

Runge, Jeffrey A; Thompson, Cameron R S; Shellito, Shawn; Dullaert, Emma C; Honda, Isabel A; Vandemark, Douglas; Pugh, Dylan; Young-Morse, Riley; Motyka, Jackie; Jones, Rebecca J; Boss, Lee Karp; Ji, Rubao

doi: 10.1093/icesjms/fsaf037pmid: N/A

Over the past two decades, a regional collaboration, now part of the US Marine Biodiversity Observation Network (MBON), has established the Wilkinson Basin Time Series (WBTS) and the Coastal Maine Time Series (CMTS) stations to observe change at subannual as well as multiannual scales in plankton of the western Gulf of Maine (GoM), USA. The stations are strategically located to monitor plankton in the Maine Coastal Current, a regional production driver, and in Wilkinson Basin, the primary deep basin in the western GoM. Here, we develop seasonal indices tracking change in mesozooplankton biomass and abundance of the planktonic copepod, Calanus finmarchicus, the energy-rich copepod that supports the regional ecosystem. The time series spans a shift in oceanographic conditions that occurred around 2010. In Wilkinson Basin, the abundance of C. finmarchicus varies by over an order of magnitude during its annual life cycle. At the WBTS station, the fall/winter late-stage abundance of C. finmarchicus has declined up to 80% between 2005 and 2023. The fall/winter abundance decline is likely related to a change in supply from the western Scotian Shelf after 2010 combined with increased seasonal predation mortality. However, in spring the abundance of C. finmarchicus remained steady, although initially increased after 2010. The trend in spring abundance corresponds to slight increases in chlorophyll a standing stock in late winter/early spring, favoring C. finmarchicus egg production. Similar trends in mesozooplankton biomass reflect the predominance of C. finmarchicus in the zooplankton community. We propose that the abundance cycles and trends in C. finmarchicus and biomass be reported regularly as seasonal indices, serving as a sentinel indicator of subarctic western GoM pelagic ecosystem function.

Eskuche-Keith, Patrick; Hill, Simeon L; Taylor, Michelle L; Hollyman, Philip; Collins, Martin A; O'Gorman, Eoin J

doi: 10.1093/icesjms/fsaf052pmid: N/A

Morphological traits reflect an organism’s ecological niche and role within ecosystems. Identifying how traits are associated with diet will therefore improve our understanding of the drivers of community structure. We combined individual morphological measurements with stomach contents from nine demersal fish species from the subantarctic island of South Georgia, where climate change is impacting the distribution of a key prey species, Antarctic krill. Cluster analysis identified five feeding guilds, with traits such as gape size proving especially useful for determining guild membership. Individuals feeding on fish had larger gapes and higher caudal and pectoral fin aspect ratios, enhancing their ability to capture and consume such large, fast prey. In contrast, benthic feeders had smaller gapes and lower fin aspect ratios, reflecting reliance on suction feeding and higher manoeuvrability. Random Forest analysis reliably predicted feeding guild membership based on these simple traits, highlighting the strong links between ecology and morphology. This study provides an important step forward in the application of trait-based approaches within the Southern Ocean. Continued research into links between morphology and diet will improve our understanding of niche partitioning in marine ecosystems and aid our ability to predict the effects of environmental change on community composition and structure.

Stamp, Thomas; West, Elizabeth; Stewart, James E; Plenty, Shaun; Robbins, Tim; Sheehan, Emma

doi: 10.1093/icesjms/fsaf035pmid: N/A

Spatial management is a widely used technique to protect sessile species or habitats. Protection of essential fish habitat is increasingly being recognized globally within fisheries management policies, requiring further practical assessments within temperate fisheries. We provide a case study for the efficacy of spatially protecting nursery sites for a highly mobile species—the European bass (Dicentrarchus labrax). Using acoustic telemetry, 146 individual fish were tracked for up to 812 days across three independent protected bass nursery areas in the Southwest UK. Within site boundaries commercial fisheries are seasonally restricted to protect vulnerable life stages. Tagged fish were re-detected >5 million times. Detections at receivers highlighted activity hot spots at or near the seaward entrance to each site. Generalized linear modelling estimated high variation in the seasonal presence/absence of fish. Due to variation in the seasonal timing and spatial boundaries of protected sites, the amount of time fish were protected ranged 1.9%–27.4%. Further work is required to link these findings to population processes e.g. mortality, growth or recruitment. We, however, highlight the vital need to consider movement patterns to ensure boundaries of spatially protected areas are relevant to species they are designed to protect.

Ainley, David G

doi: 10.1093/icesjms/fsaf060pmid: N/A

Herein, I recount an incredible period of multidisciplinary, multifaceted, multinational, cutting-edge marine research that persisted in McMurdo Sound, Ross Sea, Antarctica, from the 1960s to about the early 2000s. It was inspiring and got me started. A cadre of researchers and their students and colleagues achieved what today is known as a “Long Term Ecological Research (LTER) program,” but without the formal structure demanded for LTERs. In a way, it progressed from the scientific efforts that had been accomplished during the “Heroic age” of Antarctic exploration, in which McMurdo Sound played a huge part. That initial effort began with James Clark Ross, searching for the magnetic pole in the 1840s, through to E. Shakleton, searching for the geographic pole in the 1910s. Covered more recently by a succession of researchers was oceanography and glaciology, primary and secondary production, and food web dynamics at all levels from the benthos to midwater processes, including top predators—both bottom-up and top-down community processes. The effort persisted for decades somewhat by chance, or perhaps mutual admiration, with more than me being inspired. Sad to say, this provisional LTER is now gone, as funding and resources have been directed elsewhere. I am hugely thankful that I could take part in and be inspired by the earlier biophysical McMurdo Sound effort. This “LTER” that got me started led to my involvement in long-term, interdisciplinary research in the central California Current, centered around the Farallon Islands, and then to multidisciplinary investigations of the Southern Ocean marginal ice zone (AMERIEZ), and of the California Current food web through North Pacific GLOBEC. Current emphasis in marine bird and mammal research is returning to autecology studies of single species, especially in the use of micro-electronic devices applied to sea creatures. Thus, it is the study of marine species without the wet ocean involved. Lots learned, but without much in the way of ecological context, e.g. prey dynamics, competitors, and facilitators.

Ayyagari, Devi; Alavi, Talukder Wasi; Singh, Navlika; Barnes, Joshua; Morris, Corey; Whidden, Christopher

doi: 10.1093/icesjms/fsaf039pmid: N/A

Underwater digital monitoring systems using acoustics and video have the potential to transform marine monitoring and fisheries stock assessment but generate significant amounts of data, shifting the burden from data collection to data analysis. Machine learning (ML) is a potential solution but remains underutilized for marine monitoring, partly due to the time and cost of annotating new training datasets for each marine class and habitat. This raises the pivotal question: “How can we train marine machine learning models with limited annotated data?” We catalog publicly available marine datasets annotated for detection and classification, investigating the feasibility of leveraging a fish detector trained on three existing datasets to detect fish in a new small underwater marine dataset. We compare the accuracy and training time of pre-trained models to those without pre-training. We find pre-training with OzFish yields faster convergence and comparable performance with smaller training datasets. However, pre-training with some datasets reduced performance and increased training time. We expect our catalog of publicly available marine datasets will assist in the selection of pre-training datasets. Our results underscore the need for diverse, large, publicly available marine datasets with varied habitat and class distributions to develop and integrate ML models into automated systems for monitoring marine ecosystems.

Lee, Wei-Yu; Lan, Kuo-Wei; Naimullah, Muhamad; Lim, Irene Chia Ling; Chen, Yi-Kai; Wu, Yan-Lun

doi: 10.1093/icesjms/fsaf046pmid: N/A

Taiwan’s fishing industry is characterized by abundant marine resources and diverse fishing operation modes. However, significant investment in fishing activities has also led to substantial fishing-related waste. This study analyzed 1037 beach cleanup records collected from 2009 to 2018 across various counties and cities in Taiwan, focusing on the composition and distribution hotspots of marine debris and derelict fishing gear (DFG). The results identified Kaohsiung, Hsinchu, Taichung, Tainan, and Keelung—counties located in northern and western Taiwan—as the top five regions with the highest quantities of marine debris. Among the DFG, floating items were the most prevalent (59%), followed by fishing gear (25%) and tackle items (16%). The study further revealed that the most influential factors for all three DFG types were the average tonnage of boats and the boat number of net type (N). The composition and quantity of DFG reflect the specific characteristics of the fishing industry in each county, such as fishing gear usage, aquaculture activities, and consumer demand for fishing products. These findings provide valuable insights into the primary types of DFG and their underlying causes across different regions, offering a foundational basis for the development of targeted governmental policies to address marine debris and DFG management in Taiwan.

Durham, Sarah; Robertson, Gregory J; Wilson, Laurie; Drever, Mark C; Iles, David; Bertram, Douglas F

doi: 10.1093/icesjms/fsaf051pmid: N/A

Incidental mortality via entanglement in non-selective gillnets is a known conservation issue for marine birds globally, and specifically, in the productive marine waters of British Columbia, Canada. Three alcid species are particularly susceptible to gillnet bycatch (common murres Uria aalge, marbled murrelets Brachyramphus marmoratus (listed as “Threatened” under Canada’s Species at Risk Act) and rhinoceros auklets Cerorhinca monocerata), with estimates of mortality in commercial salmon net fisheries ranging from hundreds to thousands of individuals annually. Despite the risk posed by gillnets, the population-level impacts of mortality due to entanglement have not been estimated. Therefore, we wanted to (1) understand how varying levels of gillnet bycatch may impact population growth and persistence and (2) estimate the population size needed to withstand recent estimates of entanglement mortality. We used a simulation-based approach of matrix projection models to estimate the impact of gillnet bycatch on population growth and probability of extinction within 25 years. We found that the common murre population was the most vulnerable with current rates of gillnet bycatch producing a high probability of extinction. The population size needed to withstand current estimates of gillnet bycatch was estimated at over an order of magnitude higher than the current population size, indicating bycatch mortality in Canadian waters is taking common murres breeding in the USA. Extinction risk for marbled murrelets was estimated at ∼1% in 25 years given current estimates of gillnet bycatch, contributing to other anthropogenic threats such as loss and fragmentation of nesting habitat. Rhinoceros auklets had very low extinction risk due to the large population size compared to estimates of bycatch. This study highlights the species-specific differences in the impact of bycatch on these alcid populations and the importance of moving away from gillnets toward more selective fishing methods to reduce mortality of vulnerable seabird populations.