Age and hatching date of Japanese common squid, Todarodes pacificus, in waters around Hokkaido

Sakaguchi, Kenji; Satô, Tôru; Mitsuhashi, Masaki; Kidokoro, Hideaki

doi:10.2331/suisan.75.204

Cited by 4 publications

(3 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Baba (2021 also mentioned the possibility of mixing based on the detection of infections of the parasite Anisakis simplex, which is prevalent in the western North Pacific and not in SJ-ECS, on adult sardines caught in SJ-ECS in February and March. Some pelagic species are already known to migrate into the Sea of Japan against the strong current towards the Pacific in the Tsugaru Strait (e.g., Japanese common squid Todarodes pacificus (e.g., Sakaguchi, 2010), Masu salmon Oncorhynchus masou (e.g., Sato & Shibuya, 2015)). In this study, otolith isotope ratios for spring and summer and microstructure signatures of the nonlocals differed from those of the locals, but were mostly within the value ranges seen for the Pacific-offshores (Figs.…”

Section: Discussionmentioning

confidence: 99%

Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan

Sakamoto,

Takahashi,

Shirai

et al. 2024

Preprint

View full text Add to dashboard Cite

1. Understanding the sources of recruits is essential for stock assessments of marine fish populations. In 2014 and 2019, schools of Japanese sardine in the Sea of Japan and the East China Sea (SJ-ECS), which arrive in Japanese coastal areas for spawning each spring were shockingly sparse. Abundances of eggs and juveniles also showed abrupt declines, suggesting that sardine reproduction in the SJ-ECS was severely limited during these years. However, in spring of 2015 and 2020 age-1 fish appeared as usual in the coastal areas, along with fish of other ages, challenging the current assumption that sardine in the system is a self-recruiting subpopulation.2. To test the self-recruiting hypothesis, we analysed the stable oxygen and carbon isotopes (δ18O, δ13C) for otolith areas formed during the first spring and summer in otoliths of age-0 and age-1 sardines in 2010 and 2013–2015 year-classes captured in the SJ-ECS, as indices of temperature and metabolic trajectories. 3. Age-0 sardines generally showed a significant decrease in otolith δ18O from spring to summer, reasonably reflecting seasonal warming in the SJ-ECS. However, the majority of age-1 captured in spring 2011, 2015 and 2016 showed non-decreasing profiles of otolith δ18O, suggesting that the age-0 off the Japanese coast were not the main source of recruitment. The δ18O for summer thus indicates different migration groups: the “locals" growing up off the Japanese coast and the migrating “nonlocals". 4. The isotope ratios of the “nonlocals” overlapped with those of age-0 captured in the subarctic western North Pacific, suggesting that the “nonlocals” may be migrants from the Pacific, or perhaps an unsampled potential northward migration group in the SJ-ECS. Only in 2014 did the majority of age-1 consist of the “locals”, suggesting that the abrupt decline in catches was caused by the absence of the “nonlocals” and accompanying adults. 5. Synthesis and applicationsOur results highlight the significant uncertainty in the population structure assumed for the current stock assessment models for Japanese sardine. Concentrated investigations on recruitment processes to test and quantify the potential migration groups are recommended to improve the assessment model.

show abstract

Section: Discussionmentioning

confidence: 99%

Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan

Sakamoto,

Takahashi,

Shirai

et al. 2024

Preprint

View full text Add to dashboard Cite

show abstract

“…The calculation of the age spectrum was based on the stock of 140 days‐old individuals of IBM (Ji et al., 2020) and the fixed mortality coefficient, which is consistent with the statistical calibre of FAJ. To validate the age spectrum, we used a report of age calculated from statoliths (Sakaguchi et al., 2009) and the average mantle length of captures (FAJ, 2020, Appendix S2) to estimate the annual variation pattern of their mean age. The comparison between the age spectrum‐based capture age and FAJ records indicated a close fit; the age distribution based on statolith is close to our age spectrum in terms of mean age and peak date, providing further support for our findings (Appendix S1).…”

Section: Discussionmentioning

confidence: 99%

A new way to understand migration routes of oceanic squid (Ommastrephidae) from satellite data

Ji,

Guo

2023

Remote Sens Ecol Conserv

View full text Add to dashboard Cite

Visible Infrared Imaging Radiometer Suite (VIIRS) Boat Detection (VBD) data have been widely used to study the patterns of fishing grounds and their linking to fishery targets, particularly species mainly caught by jiggers. In line with most species in the Ommastrephidae family, the population of Todarodes pacificus is made up of various splinter cohorts concerning the timing and location of hatching. Therefore, the satellite‐recorded fishing grounds consist of groups with complex age structures and different migration directions within cohorts. This study examined the age composition of harvestable stocks (age spectrum) of T. pacificus in the Japan Sea based on an early life history individual‐based model of T. pacificus and VBD data. Using the age spectrum, we analysed the relationship between fishery effort and the age of the target group. It was found that jiggers most prefer individuals around 310 ± 20 days. Furthermore, the correlation between ambient water temperature and fishing effort revealed that T. pacificus migrated to colder waters, reaching the coldest waters at 250 ± 7.5 days before moving back towards warmer waters. We discussed a possible way to use the age‐temperature relationship to analyse the flow of VBD distributions to record the movements related to the migration of the fishing target. The results show migration‐like trajectories, which are initially parallel to the isotherm, gradually deflect towards lower temperature sides over several months, sharply turn for about a month and then move back with a slight angle to the isotherms. The method provides a potential framework to improve our understanding of the active migration of oceanic squid.

show abstract

“…In this context, accurate catch forecasts can help fishery operators make decisions and perform efficiently. In particular, fishermen and ports can effectively arrange fishing work, and relevant industrial chains such as logistics can be supported to improve logistical efficiency and ensure the freshness of aquatic products [3]. This can greatly relieve pressure on fishery workers.…”

Section: Introductionmentioning

confidence: 99%

Collaborative Forecasting and Analysis of Fish Catch in Hokkaido From Multiple Scales by Using Neural Network and ARIMA Model

et al. 2022

View full text Add to dashboard Cite

Fishery catch forecasting is a crucial aspect of aquatic research because of its relevance to establishing effective fishery management and resource allocation systems. In this study, we aim to forecast and analyze fish catch by collaboratively processing data using methods at multiple scales. To this end, we propose two computational fishery catch forecasting models. A neural network model based on the multi-timescale features of a convolutional neural network and a long short-term memory neural network is proposed and implemented to forecast short-term measures for the daily catch in the eastern ports of Hokkaido, Japan. Similarly, we propose a long-term catch forecasting and analysis model combining the autoregressive integrated moving average (ARIMA) method and a neural network to explore short-term water temperature and long-term catch dependence in the case of sparse data; we implement this method to investigate the total monthly catch in Hokkaido. The experimental results demonstrate that the proposed methods were able to effectively forecast and analyze fishery catch based on different data scales, volumes, and other complex situations. This is also the first work in the field that considers multiple perspectives.INDEX TERMS ARIMA model, fishery catch forecasting, neural network.

show abstract

Age and hatching date of Japanese common squid, Todarodes pacificus, in waters around Hokkaido

Cited by 4 publications

References 7 publications

Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan

Fisheries shocks provide an opportunity to reveal multiple recruitment sources of sardine in the Sea of Japan

A new way to understand migration routes of oceanic squid (Ommastrephidae) from satellite data

Collaborative Forecasting and Analysis of Fish Catch in Hokkaido From Multiple Scales by Using Neural Network and ARIMA Model

Contact Info

Product

Resources

About