Loop-shaped trajectories are commonly observed in the stock-recruitment relationship (SRR). A mechanism that explains why the loops emerge in SRR has been proposed, and the aim of this study was to validate this mechanism using 62 stocks that live in the waters around Japan, the Northwest Atlantic Fisheries Organization area, and elsewhere. We discuss the relationship between the age at maturity and the slope of the regression line adapted for the SRR data. Further, we discuss whether or not the age at maturity determines whether clockwise or anticlockwise loops are dominant. The results were as follows: 1) The slopes of the regression line adapted for the SRR had positive values when the age at maturity was low. As the age at maturity increased, the slopes decreased to zero and then became negative values. As the age at maturity increased even further, the slopes again changed from negative values to zero and then from zero to positive values. 2) Clockwise loops were dominant when the age at maturity was low, and anticlockwise loops were dominant when the age at maturity was high. As the age at maturity increased even more, clockwise loops again became dominant. These findings coincide well with the results presented by Tanaka et al. In the past, a density-dependent effect has been considered to be the main factor driving the fluctuations, but the present results indicated that a different mechanism may control the SRR and the fluctuations in the population.
Cite this paper
Tanaka, K. , Suzuki, N. and Sakuramoto, K. (2021). Further Analysis of Clockwise Loops and Anticlockwise Loops Observed in a Stock-Recruitment Relationship. Open Access Library Journal, 8, e7164. doi: http://dx.doi.org/10.4236/oalib.1107164.
Sundby, S. (2000) Recruitment of Atlantic Cod Stocks in Relation to Temperature and Advection of Copepod Populations. Sarsia, 85, 277-298.
https://doi.org/10.1080/00364827.2000.10414580
Chen, D.G. and Irvine, J.R. (2001) A Semiparametric Model to Examine Stock-Recruitment Relationships Incorporating Environmental Data. Canadian Journal of Fisheries and Aquaculture Sciences, 58, 1178-1186.
https://doi.org/10.1139/f01-037
Myers, R.A., Barrowman, N.J., Hutchings, J.A. and Rosenberg, A.A. (1995) Population Dynamics of Exploited Fish Stocks at Low Population Levels. Science, 269, 1106-1108. https://doi.org/10.1126/science.269.5227.1106
Szuwalski, C.S., Vert-Pre, K.A., Punt, A.E., Branch, T.A. and Hilborn, R. (2015) Examining Common Assumptions about Recruitment: A Meta-Analysis of Recruitment Dynamics for Worldwide Marine Fisheries. Fish and Fisheries, 16, 633-640. https://doi.org/10.1111/faf.12083
Sakuramoto, K. (2005) Does the Ricker or Beverton and Holt Type of Stock-Recruitment Relationship Truly Exist? Fisheries Science, 71, 577-592.
https://doi.org/10.1111/j.1444-2906.2005.01002.x
Sakuramoto, K. (2013) A Recruitment Forecasting Model for the Pacific Stock of the Japanese Sardine (Sardinops melanostictus) That Does Not Assume Density-Dependent Effects. Agricultural Sciences, 4, 1-8.
https://doi.org/10.4236/as.2013.46A001
Sakuramoto, K. (2013) A Common Concept of Population Dynamics Applicable to both Thrips imaginis (Thysanoptera) and the Pacific Stock of the Japanese Sardine (Sardinops melanostictus). Fisheries and Aquaculture Journal, 4, 085.
Sakuramoto, K. (2015) A Stock-Recruitment Relationship Applicable to Pacific Bluefin Tuna and the Pacific Stock of Japanese Sardine. American Journal of Climate Change, 4, 446-460. http://dx.doi.org/10.4236/ajcc.2015.45036
Sakuramoto, K. (2016) Case Study: A Simulation Model of the Spawning Stock Biomass of Pacific Bluefin Tuna and Evaluation of Fisheries Regulations. American Journal of Climate Change, 5, 245-260. http://dx.doi.org/10.4236/ajcc.2016.52021
Fisheries Agency and Fisheries Research and Education Agency of Japan (2019) Marine Fisheries Stock Assessment and Evaluation for Japanese Waters (Fiscal Year 2018/2019). Marine Fisheries Stock Assessment and Evaluation for Japanese Waters, Kanagawa. https://abchan.fra.go.jp/
Tanaka, K., Suzuki, N. and Sakuramoto, K. (2017) Clockwise Loops and Anticlockwise Loops Observed in a Stock-Recruitment Relationship. Open Access Library Journal, 4, e3688. https://doi.org/10.4236/oalib.1103688