Fisheries ResearchPub Date : 2024-07-24DOI: 10.1016/j.fishres.2024.107121
Caroline Benfer , Eric Annis , Jesica Waller , Joshua T. Carloni , Kathleen Reardon , LeAnn Whitney , Rachel Lasley-Rasher , Heidi Henninger
{"title":"Distribution of lobster larvae, Homarus americanus, and zooplankton prey in the gulf of maine and georges bank stock area","authors":"Caroline Benfer , Eric Annis , Jesica Waller , Joshua T. Carloni , Kathleen Reardon , LeAnn Whitney , Rachel Lasley-Rasher , Heidi Henninger","doi":"10.1016/j.fishres.2024.107121","DOIUrl":"10.1016/j.fishres.2024.107121","url":null,"abstract":"<div><p>The American lobster, <em>Homarus americanus</em> H. Milne-Edwards, 1837 supports a valuable fishery subject to rapid warming of the Gulf of Maine (GOM) and Georges Bank (GBK). Comprehensive information related to large-scale larval distribution is lacking due to the logistical challenge of sampling their hyper-dispersed larvae. In 2021, we established seasonal abundance patterns of larvae and their prey in the GOM on an unprecedented spatial scale with a season-long survey at transects spanning approximately 300 km of coastline. We compared the current distribution of larvae with historical surveys with respect to differences between inshore and offshore (5 versus 40 km), and between eastern and western hydrographic regions. We also examined spatial and temporal patterns in the abundance of zooplankton prey. The distribution of recently hatched stage I larvae extended offshore at the transect off Rye, NH and was consistent with the reported movement of ovigerous lobsters offshore to hatch their eggs. By contrast, stage I larvae were most abundant nearshore and rare offshore at other transects along the coast. Our results confirmed historical patterns of high abundance of competent stage IV larvae in the western Gulf of Maine and low abundance in the east. We also identified the potential for a temporal mismatch between the abundance of larvae and the biovolume of copepods at transects in Milbridge, ME and Rye, NH with peak copepod abundance occurring either well before or after the peak abundance of lobster larvae. The data collected fill a gap in our understanding of larval distributions and seasonal progression in the Gulf of Maine, establish a baseline for future studies, and provide an opportunity to validate established biophysical models of larval transport. Yet a longer time series of broad-scale surveys is needed to better understand intricacies of factors influencing larval abundance and distribution. The project was an industry-led collaboration with government and academic scientists providing proof of concept for future collaborative research.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107121"},"PeriodicalIF":2.2,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-23DOI: 10.1016/j.fishres.2024.107113
S.J.W.W.M.M.P. Weerasekera , Noel G. Cadigan , Kunasekaran Nirmalkanna , Paul M. Regular , Rick M. Rideout
{"title":"Trends in population starvation mortality based on a spatiotemporal model of condition: Part 1: A case study of Atlantic cod on the Southern Grand Bank","authors":"S.J.W.W.M.M.P. Weerasekera , Noel G. Cadigan , Kunasekaran Nirmalkanna , Paul M. Regular , Rick M. Rideout","doi":"10.1016/j.fishres.2024.107113","DOIUrl":"10.1016/j.fishres.2024.107113","url":null,"abstract":"<div><p>Fish condition is often defined as a deviation in the relationship between fish weight and length, indicating if the fish is leaner or fatter than the average. The proportion of a stock in critically poor condition may indicate a component of the total natural mortality rate <em>M</em>, which has been called the starvation mortality rate (i.e., <em>M</em><sub><em>K</em></sub> ≤ <em>M</em>). The weight-length relationship may vary spatially and temporally (both between and within years). Hence, <em>M</em><sub><em>K</em></sub> may also vary the same way. We developed a spatiotemporal condition model to derive a spatiotemporal and length-specific index of <em>M</em><sub><em>K</em></sub>. We aggregated <em>M</em><sub><em>K</em></sub> across space and months to produce an annual and length-specific <em>M</em><sub><em>K</em></sub> index for the entire stock, as a potential input to assessment models. We applied the model to survey data for cod on the Southern Grand Bank of Newfoundland. Our results indicated that <em>M</em><sub><em>K</em></sub> was: 1) higher in the spring than the fall, 2) higher for cod between 55 and 80 cm and cod ≥ 120 cm, and 3) higher during 1991–1993 when the stock declined substantially, but was also high in 2016. We discuss potential drivers of starvation mortality as well as how this information can be included in a stock assessment model to improve fisheries management advice.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107113"},"PeriodicalIF":2.2,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0165783624001772/pdfft?md5=6080a8440a16ed12b605fb9180b48932&pid=1-s2.0-S0165783624001772-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141930152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-21DOI: 10.1016/j.fishres.2024.107112
Jason S. Goldstein , Benjamin C. Gutzler , Abigail Lemmon , Joshua T. Carloni , Marlies Betka , Steven H. Jury
{"title":"Long distance swimmers in warming waters: Active transport in postlarval American lobsters (Homarus americanus) in the context of climate change in the Gulf of Maine","authors":"Jason S. Goldstein , Benjamin C. Gutzler , Abigail Lemmon , Joshua T. Carloni , Marlies Betka , Steven H. Jury","doi":"10.1016/j.fishres.2024.107112","DOIUrl":"10.1016/j.fishres.2024.107112","url":null,"abstract":"<div><p>Recent declines in American lobster (<em>Homarus americanus</em>) settlement in the Gulf of Maine (GoM) have raised questions concerning the effects of climate change on lobster recruitment. Postlarval lobsters are strong swimmers that typically transit to inshore settlement habitats, an energy-intensive process that may be a metabolic bottleneck. Using 72-hr laboratory swimming challenges, we tested the performance of laboratory-reared postlarvae at historically favorable temperatures (15°C), as well as projected end-of-century GoM temperatures (22°C) to determine if increased water temperatures may impair the swimming abilities needed to reach settlement habitats. Video observation and analysis revealed that postlarvae in the 22°C treatment spent 25 % less time actively swimming compared with postlarvae at 15°C. Postlarvae in the 22°C swimming trials also had lower lipid content after the swimming challenge when compared with pre-trial controls; however, dry weight and protein content were not significantly different between the treatment groups. When sequential trials were run using postlarvae from the same clutch, dry weights increased with time since metamorphosis. Metabolic rates for lobsters increase in warmer temperatures, so it is possible that decreased swimming at warmer temperatures may be an adaptive strategy for energy conservation in less favorable, thermally stressful, conditions. Overall, decreased swimming activity in warmer waters may be a contributing factor in shifting patterns of lobster recruitment in the GoM.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107112"},"PeriodicalIF":2.2,"publicationDate":"2024-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141736623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-19DOI: 10.1016/j.fishres.2024.107116
Irina M. Benson , Thomas E. Helser , Beverly K. Barnett
{"title":"Fourier transform near infrared spectroscopy of otoliths coupled with deep learning improves age prediction for long-lived northern rockfish","authors":"Irina M. Benson , Thomas E. Helser , Beverly K. Barnett","doi":"10.1016/j.fishres.2024.107116","DOIUrl":"10.1016/j.fishres.2024.107116","url":null,"abstract":"<div><p>The northern rockfish (<em>Sebastes polyspinis</em>) is an economically valuable, long-lived species distributed over the continental shelf of the North Pacific Ocean. Ages for this species which can be in excess of 80 years comprise an essential component of models for assessing population status and are crucial for fisheries management. Traditional microscope-based methods of estimating age using otoliths can be time-intensive and prone to reader variability. We explored the application of Fourier transform near infrared (FT-NIR) spectroscopy coupled with multimodal convolutional neural networks (MMCNN) for age prediction. Our study included 2613 FT-NIR scans and associated ages of northern rockfish otoliths from years 2013–2019, with ages ranging from 3 to 66 years. The optimal MMCNN model demonstrated strong performance, yielding an R<sup>2</sup> of 0.92 and an RMSE of 3.38 for the training set and an R<sup>2</sup> of 0.89 and an RMSE of 3.74 for the test set. Spectral information in the 11,500 to 4000 cm⁻¹ wavenumber range, otolith weight, and other biological/geospatial data contributed to age predictions that were comparable to traditional age estimates. Despite challenges, FT-NIR spectroscopy coupled with MMCNN emerged as a promising alternative for age estimation in long-lived species. This approach, while demonstrating effectiveness for northern rockfish, could be a valuable tool for diverse fish species, supporting sustainable fisheries practices and population monitoring.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107116"},"PeriodicalIF":2.2,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-19DOI: 10.1016/j.fishres.2024.107109
A. Pérez San Juan , M.L. Ramos Alonso , V. Sierra , J.C. Báez
{"title":"Undetected silky sharks (Carcharhinus falciformis) in the wells of the tropical tuna purse seine fleet in the Indian Ocean","authors":"A. Pérez San Juan , M.L. Ramos Alonso , V. Sierra , J.C. Báez","doi":"10.1016/j.fishres.2024.107109","DOIUrl":"10.1016/j.fishres.2024.107109","url":null,"abstract":"<div><p>The catches of the Spanish purse seine fleet targeting tropical tunas in the Indian Ocean have been systematically sampled in port and at sea by scientific research centres since the fleet began to operate in the 1980s. During these samplings, some silky shark (<em>Carcharhinus falciformis</em>) specimens were found in the wells of these vessels which had not previously been recorded by at-sea scientific observers. To quantify the occurrence of these undetected incidental catches of silky sharks, this study compared two sets of data: on-board data collected by scientific observers and port sampling data. The European Union's long-term data collection program (PNDB), coordinated by the Spanish Fisheries Secretariat, provides on-board data collected by scientific observers as well as port sampling data which is collected while a vessel arrives to the port to begin unloading. The sampling focused on target species up until January 2021, when sampling started including non-target species as well. The datasets examined in this study are from January 2021 to December 2022. The results show significant differences between silky shark sizes observed on-board and those measured in port. A logistic model indicates a significant probability of observing silky sharks in wells, with a strong goodness of fit and high discrimination capacity as a function of the total catch of the fishing operation. Further analysis reveals differences in average sizes and weights of silky sharks caught in free-schools compared with those caught with tuna schools aggregated beneath Fish Aggregating Devices or FADs. The presence of unnoticed silky sharks suggests unreported captures, indicating that rates of mortality of the species are underestimated. In conclusion, the research emphasizes the need to address undetected silky shark bycatch in the purse seine fishery in the Indian Ocean. Obtaining accurate data and understanding the magnitude of this bycatch are crucial for developing management strategies that mitigate the impact and promote the sustainability of silky shark populations in the region.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107109"},"PeriodicalIF":2.2,"publicationDate":"2024-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0165783624001735/pdfft?md5=bcd43fce133f7dfdc8bea2264fd57f51&pid=1-s2.0-S0165783624001735-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-18DOI: 10.1016/j.fishres.2024.107117
Erica P. Ross , Casey B. Butler , Carly M. Hannah, Thomas R. Matthews
{"title":"Reflex impairment as a predictor of mortality in Panulirus argus: Implications for the live export market","authors":"Erica P. Ross , Casey B. Butler , Carly M. Hannah, Thomas R. Matthews","doi":"10.1016/j.fishres.2024.107117","DOIUrl":"10.1016/j.fishres.2024.107117","url":null,"abstract":"<div><p>Spiny lobster (<em>Panulirus argus</em>) fishers in Florida garner the highest price for lobsters that are sold to the live export market. Lobsters are “graded” using a visual qualitative assessment before export to remove any lobsters unlikely to survive shipping. The current qualitative grading process, while effective in reducing mortality, is conservative and results in a significant number of healthy lobsters being sold at lower prices for the frozen market. This study sought to develop lobster grading methods that more accurately predict lobster mortality to increase the proportion of lobsters suitable for the high-value live export market; thus, we compared two alternative grading/mortality predictor methods to the current exporter grading method. For this, we examined nine candidate lobster reflexes (i.e., appendix turgor and movement in response to a probe) and eight other lobster physiologic and morphometric parameters (i.e., number of injuries, molt stage, nutritional condition via blood serum protein, presence of shell disease, presence of tail fan necrosis, sex, and size) to develop two reflex action mortality predictors. The first mortality predictor was developed using reflex impairment alone, and the second mortality predictor was a quantitative mortality model developed with as many parameters as necessary to increase the model’s performance in predicting mortality. The classification accuracy of these mortality assessments (reflex impairment and quantitative mortality model) was then compared with the current qualitative grading process that occurs prior to shipping. The current grading process was a moderate predictor of mortality (area under the receiver operating characteristic curve, AUC 0.807), which correctly predicted the outcome (survival or mortality) 74.5 % of the time. Both mortality models performed better than the current grading process. A logistic regression indicated reflex impairment alone was a significant predictor of mortality (AUC 0.897), which was able to correctly predict mortality 88 % of the time. The quantitative mortality model included three predictors – blood serum protein, reflex impairment, and collection month – and was also a significant predictor of mortality (AUC 0.938) and had the highest accuracy (90 %) of the three assessments we examined. Results from this study show that mortality assessments using reflex impairment and health indicators can successfully predict mortality in <em>P. argus</em>. These mortality assessments could be applied at fish houses to increase the value of the fishery (3–9 %, $1.71 million USD/season) by increasing the number of lobsters sold for live export.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107117"},"PeriodicalIF":2.2,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0165783624001814/pdfft?md5=8435538ddd56242683b5d72544e6cd61&pid=1-s2.0-S0165783624001814-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Let’s measure it: An approach of high-resolution estimates of bottom fixed net fishing effort at national level","authors":"Nuno Sales Henriques , Karim Erzini , Jorge M.S. Gonçalves , Tommaso Russo","doi":"10.1016/j.fishres.2024.107118","DOIUrl":"10.1016/j.fishres.2024.107118","url":null,"abstract":"<div><p>Fisheries are one of the most important food sources for human consumption whilst being amongst the most impacting and extractive activities happening within the marine environment, which makes it imperative to properly manage this activity. To improve fisheries management, the precise quantification of fishing effort is of the outmost importance. Yet, present methods for effort estimation, especially at broad scales, are hampered by difficulties in data access and usually rely on coarse effort metrics or on costly data collection for quantifying fishing effort with higher resolution. In the present work, we propose an approach of high-resolution fishing effort estimates of net fishing, as length of nets operated by a given fleet, at the national level. It relies on sampling of effort, derived from classified and easy to access vessel tracking data – AIS, and fishery dependent data – logbook and landings data. The proposed methodology combines trip-based effort estimates, derived from AIS data, as a foundation to extrapolate the total fishing effort, through the number of fishing trips linked to official landings and logbook data. It is estimated that in the years from 2014 to 2020 an average of 180 200 km of static nets (gillnets and trammel nets), which corresponds to approximately 4.5 and 210 times the lengths of the equator and the Portuguese Atlantic coastline respectively, are used in Portuguese mainland waters each year, by a fleet of slightly more than 100 vessels. The presented methodology allows to quantify and study the variation of the nominal fishing effort, at country level, with a higher resolution than what is usually used and at very low cost. We argue that such methodologies need to be developed and explored in order to have better and more comprehensive estimates of fishing effort which will contribute and improve the sustainable management of fisheries and the marine environment.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107118"},"PeriodicalIF":2.2,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0165783624001826/pdfft?md5=b1fcbf4bb6f7a5bf0218f762dcb6c5c4&pid=1-s2.0-S0165783624001826-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141728577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-18DOI: 10.1016/j.fishres.2024.107111
Haikun Xu, Mark N. Maunder, Cleridy E. Lennert-Cody, Carolina V. Minte-Vera
{"title":"Evaluating the impacts of reduced longline fishing effort on the standardization of longline catch-per-unit-effort for bigeye tuna in the eastern Pacific Ocean","authors":"Haikun Xu, Mark N. Maunder, Cleridy E. Lennert-Cody, Carolina V. Minte-Vera","doi":"10.1016/j.fishres.2024.107111","DOIUrl":"10.1016/j.fishres.2024.107111","url":null,"abstract":"<div><p>Indices of relative abundance directly inform how population abundance changes over time, providing one of the most important pieces of information for a stock assessment. Ideally, indices of abundance should be calculated based on fishery-independent survey data. Survey data are characterized by a spatially random or fixed sampling design, and consistent employment of the same fishing gear and fishing operation across time. However, the unavailability of survey data for most tuna species means that the derivation of abundance indices for these species comes solely from fishery-dependent catch-per-unit-effort (CPUE). We conduct two simulation experiments, based on real fishery-dependent longline data, to quantitatively evaluate the impacts of reduced fishing effort on the standardized longline CPUE for bigeye tuna in the eastern Pacific Ocean. The key findings of the two simulation experiments are 1) a reduced spatial coverage of CPUE data leads to increased bias in the abundance index; 2) the index bias has a minor long-term trend if the reduced spatial coverage of CPUE data is not caused by local depletion; and 3) that bias has a positive long-term trend (i.e., hyper-stable abundance index) if the reduced spatial coverage of CPUE data co-occurs with a local depletion in the abandoned area. This bias, however, can be significantly reduced if the CPUE standardization model includes a temporal correlation structure in spatiotemporal random fields. In addition, the CPUE standardization model provides more realistic estimates of the coefficient of variation of fish abundance when its spatiotemporal random fields are assumed to be correlated in time. This study underscores the necessity of accounting for the temporal correlation structure in spatiotemporal random fields in cases where local depletion and depletion-driven fishery contraction co-occur.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107111"},"PeriodicalIF":2.2,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141637904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-17DOI: 10.1016/j.fishres.2024.107102
Nathan D. Stewart , Kyle L. Wilson , Alex Hanke
{"title":"Estimating age-at-maturity for individual Atlantic bluefin tuna (Thunnus thynnus) from back-calculated growth trajectories","authors":"Nathan D. Stewart , Kyle L. Wilson , Alex Hanke","doi":"10.1016/j.fishres.2024.107102","DOIUrl":"10.1016/j.fishres.2024.107102","url":null,"abstract":"<div><p>We fit a biphasic Lester Model to back-calculated size-at-age data for Atlantic bluefin tuna (<em>Thunnus thynnus</em>) captured in the western Atlantic management area that had been genetically assigned to either the western (Gulf of Mexico) or eastern (Mediterranean) spawning stocks. We tested the hypothesis that spawning-stock variation exists in age-at-maturity for this species using a Bayesian approach to incorporate and compare the support for different growth models and maturity scenarios considered for the western spawning stock. The biphasic Lester Model out-performed the uniphasic von Bertalanffy model and showed good fits for describing individual growth variability in Atlantic bluefin tuna. The Lester Model provided estimates of individual age-at-maturity and spawning, from which spawning ogives were generated and compared to two reproductive scenarios currently considered for the western spawning stock; either an early (age at 50 % maturity at 4 years) or late maturity scenario (age at 50 % maturity at 10). The results derived from the Lester Model demonstrate a lack of stock-specific variation in reproductive dynamics for Atlantic bluefin tuna, and provide support for an early maturity scenario for the western spawning stock.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107102"},"PeriodicalIF":2.2,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141637903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fisheries ResearchPub Date : 2024-07-15DOI: 10.1016/j.fishres.2024.107110
Reid W. Steele , Jin Gao , Mariano Koen-Alonso , Paul M. Regular
{"title":"Exploring capelin (Mallotus villosus) population dynamics using Empirical Dynamic Modelling (EDM)","authors":"Reid W. Steele , Jin Gao , Mariano Koen-Alonso , Paul M. Regular","doi":"10.1016/j.fishres.2024.107110","DOIUrl":"10.1016/j.fishres.2024.107110","url":null,"abstract":"<div><p>Capelin (<em>Mallotus villosus</em>) populations on the Newfoundland shelf collapsed in the early 1990s, coinciding with a regime shift and greatly reduced capelin and groundfish biomasses which both persist to this day. The biphasic nature of this stock’s history suggest it may experience nonlinear dynamics, which are difficult to predict using linear models. This study explores the application of Empirical Dynamic Modelling (EDM) nonlinear, nonparametric time series forecasting tools to capelin biomass data, seeking to detect nonlinear dynamics, compare performance of linear and nonlinear multivariate predictive models, identify drivers of capelin biomass using convergent cross-mapping, and measure the sign and strength of capelin species interactions. We found capelin dynamics were nonlinear, and multivariate EDM predictive models returned equal or improved model diagnostics to linear models in most situations. We identified long-term climate dynamics and timing of sea ice retreat as the primary drivers of capelin dynamics, but some indications of potential top-down effects from Greenland halibut were also detected. Atlantic cod biomass, and capelin catch were investigated as potential drivers of capelin dynamics, but both were found more likely to be driven by capelin dynamics. Overall, our results support the idea that capelin dynamics are mostly bottom-up driven, and that capelin itself is a driver of its predators, suggesting that the overall ecosystem may be largely bottom-up driven. This study also clearly identifies the utilities of EDM as a complementary tool for stock assessments by detecting and forecasting nonlinear stock dynamics, and identifying and characterizing relationships between stock biomass and the factors which drive it.</p></div>","PeriodicalId":50443,"journal":{"name":"Fisheries Research","volume":"278 ","pages":"Article 107110"},"PeriodicalIF":2.2,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141623691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}