Model for stock-recruitment dynamics of the Peruvian anchoveta (<i>Eugraulis ringens</i>) off Peru

Abstract

This paper was aimed at reexamining the validity of the results from Cahuin et al. (Estuar. Coast. Shelf Sci. 84, 2009) and identifying a model to describe the stock-recruitment relationship of the Peruvian anchoveta (Eugraulis ringens). Regression analysis was used to determine if density-dependent effects were present. The analysis did not show the existence of any densitydependent effects. It is important to use environmental factors and take observational and process errors into account when attempting to identify density-dependent effects in fish populations. Sea surface temperature (SST) and Southern Oscillation Index (SOI) were used as independent variables to fit the recruitment dynamics of the anchoveta. Both SST and SOI were found to be significantly important parameters in structuring anchoveta dynamics according to Akaike Information Criterion (AIC) and R 2 values. The results of this study do not correlate with the findings of Cahuin et al., (2009), where density-dependent effects and the presence of regimes were detected. In conclusion, the recruitment R t is essentially determined in proportion to spawning stock biomass S t , and then environmental factors in year t further change the recruitments. This mechanism is completely same with that for Japanese sardine proposed by Sakuramoto (The Open Fish. Sci. 5, 2012).

A Common Concept of Population Dynamics Applicable to Both Thrips imaginis (Thysanoptera) and the Pacific Stock of the Japanese Sardine(Sardinops melanostictus)

“…In there, only for 3cases (Oct.-Nov., Dec.-Jan., and Jan.-Feb.), the slopes were not significantly different from unity. For other 2 cases (Apr.-May and Aug.-Sep.), the 95% confidence interval of [26] is explained well using the same concept of the fluctuation mechanism proposed in this paper. That is, my concept for the mechanism in population fluctuation coincides well with that by Davidson and Andrewartha [16] and Andrewartha and Birch [27] in that the density-dependent effect is not a key factor or a negligible factor in controlling the population size.…”

A Stock-Recruitment Relationship Applicable to Pacific Bluefin Tuna and the Pacific Stock of Japanese Sardine

“…Therefore, the apparent SRRs for the species will show increasing loops. This can also be seen in the SRRs for anchovies [15], mackerel and other species [16]. On the contrary, for species with a long reproduction cycle, the apparent SRRs will scatter widely and will show anti-clockwise loops with no trend, such as that observed in bluefin tuna.…”

Influence of Climatic Conditions on the Time Series Fluctuation of Yellowfin Tuna <i>Thunnus albacares</i> in the South Pacific Ocean

“…The difference in the lag periods for the SOI might be attributed to its influence on the spatial distribution of various prey in relation to the different dietary preferences and life stages of the yellowfin tuna in Zone 1, Zone 2 and Zone 3 [30]- [32]. The effect of SOI on small fish species has been previously reported [33] [34]. Lehodey [12] showed that the recruitment of yellowfin tuna was favorable during positive Pacific Decadal Oscillation (PDO) and El Niño events and unfavorable during negative PDO and La Niña events.…”