Age and growth of chub mackerel (Xcomber japonicus) in the East China and Yellow Seas using sectioned otolith samples

Abstract

Although chub mackerel (Scomber japonicus) is a primary pelagic fish species, we have only limited knowledge on its key life history processes. The present work studied the age and growth of chub mackerel in the East China and Yellow Seas. Age was determined by interpreting and counting growth rings on the sagitta otoliths of 252 adult fish caught by the Chinese commercial purse seine fleet during the period from November 2006 to January 2007 and 150 juveniles from bottom trawl surveys on the spawning ground in May 2006. The difference between the assumed birth date of 1st April and date of capture was used to adjust the age determined from counting the number of complete translucent rings. The parameters of three commonly used growth models, the von Bertalanffy, Logistic and Gompertz models, were estimated using the maximum likelihood method. Based on the Akaike Information Criterion (AIC), the von Bertalanffy growth model was found to be the most appropriate model. The size-at-age and size-at-maturity values were also found to decrease greatly compared with the results achieved in the 1950s, which was caused by heavy exploitation over the last few decades.

Length-weight, condition factors, age, and growth of Scomber japonicus (Houttuyn, 1782) from the Egyptian Mediterranean Sea

“…Such differences may be due to different habitats, methods used length range, and number of specimens. The growth performance index (Ø) of 2.68 was higher than some previous studies (Aguayo & Steffens,1986;Kiparissis et al, 2000 andCengiz 2012), but lower than others (Tuggac, 1957;Mendo, 1984;Perrotta, 1992, Lorenzo et al, 1995, Perrotta et al, 2005, Gang et al, 2008and Samuel et al, 2016. Differences in habitats were correlated with increasing age at the high growth performance shown in the table, whereas the present index and others with lower values were slightly similar to the same/lower age groups.…”

Growth Heterogeneity of Chub Mackerel (Scomber japonicus) in the Northwest Pacific Ocean

“…A total of 175 Chub mackerel were aged. The criteria for age determination for this species in this study followed the process from past Chub mackerel age analysis, which stated that a translucent and all-opaque ring (summer growth zone) is deposited on the otolith every year [11,12,20]. Each otolith was read by two readers.…”

“…Relative condition factors are an effective method to compare the relationship between body weight and length of fish at different life stages [22,48]. The condition of the population status of Chub mackerel in recent years was lower as compared to those of the early stages when Chub mackerel fishery began [6,11,41]. This information directly reflects the change of the relative condition factors compared with reported Chub mackerels before 2006; in recent years, the relative condition factors of Chub mackerel have been decreasing (the relative condition factors of Chub mackerel are less than 1).…”

“…The current study on the fishery biology of Chub mackerel mainly focuses on stock structure [2,3], reproduction [1,4], and mortality rates [5,6]. Age-growth relationships are one of the most important parameters in understanding fish life history and population dynamics [7][8][9][10][11][12]. Past studies have reported that Chub mackerels' growth is influenced by recruitment and environmental variables, and their growth is not significantly different between sexes [13].…”

“…The lack of research with the aim to implement management measures on the Chub mackerel population in the high seas off the northwest Pacific Ocean may not only directly affect the interests of countries' pelagic fisheries but also indirectly affect the status of Chub mackerel stocks in the coastal waters opened to the northwest Pacific Ocean. There are few studies on Chub mackerel fishery in the high seas of China off the northwest Pacific Ocean; however, to date, no updated research on age and growth directly related to Chub mackerel in Chinese waters has been published [11,12,14]. Meanwhile, still in east Asia, Japanese scholars have done some studies based on their surveys in the offshore and distant waters off the Japanese coasts [15][16][17].…”