SHORT COMMUNICATION Scomber japonicus, H. is a better candidate species for juvenile production activities than Scomber scombrus, L. Diego Mendiola 1 ,YohYamashita 2 , Michiya Matsuyama 3 , Paula Alvarez 1 & Masaru Tanaka 2 1 AZTI-Tecnalia, Marine Research Division, Herrera Kaia; Portualdea, Pasaia, Spain 2 Maizuru Fisheries Research Station, Field Science Education and Research Center, Kyoto University, Kyoto, Japan 3 Graduate School of Agriculture, Kyushu University, Fukuoka, Japan Correspondence: D Mendiola, AZTI-Tecnalia, Marine Research Division, Herrera Kaia; Portualdea, s/n; 20110 Pasaia, Spain. E-mail: dmendiola@pas.azti.es Two closely related mackerel species ( Scomber scombrus , L. and Scomber japonicus , H.) cohabiting in the Bay of Biscay (Zardoya, Castilho, Grande, Favre-Krey, Caetano, Marcato, Krey & Patarnellos 2004) are regarded as cul- tivable (Mendiola, Alvarez, Cotano & Mart|¤ nez de Murgu|¤a 2007), as ¢shing practices increase. Over the past decades, interest in the culture of new marine pelagic species has increased dramatically in response to several reduced supply examples from wild ¢sheries (e.g. Sinclair & Murawski 1997; Beaugrand, Brander, Lindley, Souissi & Reid 2003), high market prices and the suitability of some ¢sh species for culture (Tilseth 1990; Allsopp 1997). Mackerel is a much used species, as live bait, in the ¢shery of tuna (Rodriguez-marin, Arrizabalaga, Ortiz, Rodriguez-cabello, Moreno & Kell 2003). Likewise, this ¢sh represents an important protein source for direct human consumption and is a typical food product used in the aquaculture industry (Naylor, Goldburg, Primavera, Kautsky, Beveridge, Clay, Folke, Lubchenco, Mooney & Troell 2000). Nowadays, there is no interest in the commercial culture of this species; however, in response to the increasing demand of mackerel juveniles, as a live bait of quality for the ¢sh- ing of tuna (Rodriguez-Marin et al . 2003), the experi- mental cultivation of this species has recently become a challenge in the Bay of Biscay (Mendiola & Alvarez 2007) and in the south of Japan (Matsuyama, Shiraishi, Sundaray, Rahman, Ohta & Yamaguchi 2005). A new market for the tuna bait industry could gain popularity if rentable juvenile production techniques were devel- oped for mackerel. This ¢sh species displays inherent characteristics of high early growth potential (Tanaka, Kaji, Naka- mura & Takahashi 1996). Taking into account that the aim of aquaculture is to achieve the maximum growth rate of each individual ¢sh, within a certain time (Kjorsvik, Pittman & Pavlov 2004), such a basic concept could support the consideration of mackerels as cultivable ¢sh. The economical value of some spe- cies within the aquaculture industry has been stimu- lated previously on the basis of detailed studies of early growth and the factors in£uencing growth rates (e.g. Pittman, Skiftesvik & Harboe 1989; Bell & Gervis 1999; Khemis, de la Noue & Audet 2000; Chereguini, de la Banda, Rasines & Fernandez 2001). In contrast to detailed information available for other marine ¢sh (Svasand, Ottera, Taranger, Litvak, Skiftesvik, Bjelland, Pavlov, Holm, Harboe, Mangor- jensen, Norberg & Howell 2004; Howell & Yamashita 2005), information concerning the culture of mack- erel (Juell, Hemre, Holm & Lie 1998; Masuda, Shoji, Aoyama & Tanaka 2002; Matsuyama et al . 2005; Mendiola & Alvarez 2007, Mendiola, Ibaibarriaga & Alvarez 2007) is scarce. In the present study, we compile baseline informa- tion on the relative early growth trends of both spe- cies of mackerel. Further, we compare their best suitability for aquaculture activities. Aquaculture Research, 2008, 39, 1122^1127 doi: 10.1111/j.1365-2109.2008.01959.x r 2008 The Authors 1122 Journal Compilation r 2008 Blackwell Publishing Ltd