Journal of the Marine Biological Association of the United Kingdom cambridge.org/mbi Original Article Cite this article: Zorica B, Čikeš Keč V, Pešić A, Gvozdenović S, Kolitari J, Mandić M (2018). Spatiotemporal distribution of anchovy early life stages in the eastern part of the Adriatic Sea in relation to some oceanographic features. Journal of the Marine Biological Association of the United Kingdom 1–7. https:// doi.org/10.1017/S0025315418001145 Received: 21 February 2018 Revised: 12 November 2018 Accepted: 16 November 2018 Key words: Adriatic; ichthyoplankton; small pelagics Author for correspondence: B. Zorica, E-mail: zorica@izor.hr © Marine Biological Association of the United Kingdom 2018 Spatiotemporal distribution of anchovy early life stages in the eastern part of the Adriatic Sea in relation to some oceanographic features B. Zorica 1 , V. Čikeš Keč 1 , A. Pešić 2 , S. Gvozdenović 2 , J. Kolitari 3 and M. Mandić 2 1 Institute of Oceanography and Fisheries, Šet. I. Meštrovića 63, 21000 Split, Croatia; 2 University of Montenegro – Institute of Marine Biology, Dobrota bb, P Box 69, 85330 Kotor, Montenegro and 3 Agriculture University, Fishery and Aquaculture Laboratory, Lagjia 4, rruga ‘Egnatia’, Durres, Albania Abstract During the summer of 2013 two scientific surveys (northern, at the beginning of July and southern, at the end of July) were carried out along the eastern Adriatic Sea. In these surveys, ichthyoplankton samples of anchovy (Engraulis encrasicolus, Linnaeus 1758) eggs and larvae were collected. In the whole investigated area, egg and larvae abundance varied from 2.61 to 1040.24 eggs m -2 (geometric mean ± CL: 25.43 ± 1.48 eggs m -2 ) and 2.73 larvae m -2 to 611.14 larvae m -2 (geometric mean ± CL: 17.07 ± 1.41 larvae m -2 ), respectively. Higher abun- dance of anchovy early life stages was noted in the northern part of the investigated area. The length of the collected specimens lay within the range of 2.39–3.68 mm and those individuals were less than 12 h old. Analysis of spatial and temporal distribution of collected anchovy early life stages indicated their higher abundance in areas of upwelling (four areas were dis- tinguished on the eastern Adriatic side). Larger and older specimens were collected at the beginning of July in the northern part of Adriatic indicating that the anchovy population in the Adriatic tends to shift among its spawning centres in this area. In general, anchovy eggs were accompanied by its larvae (r = 0.453, P < 0.05), while statistically significant negative correlation was obtained between egg abundance and temperature (r = -0.380, P < 0.05) as well as sea depth (r = -0.321, P < 0.05). Introduction The worldwide scientific community, as well as commercial fishermen, are well aware of con- siderable biomass fluctuations of small pelagic fish species, these having been observed over quite a long period of time. Throughout this time, scientists have attempted to reveal the trig- gers for these oscillations, but have actually discovered the wide complexity of the observed issue. All discovered biotic or abiotic factors that might or might not act in synergy during the fishes’ lifetimes lead to this inter- and intra-annual small pelagic biomass variability (Agostini & Bakun, 2002; Santojanni et al., 2006; Zorica et al., 2013, 2014; Bonanno et al., 2014; Grbec et al., 2015). Hence, a better understanding of each part of the pelagic ecosystem, including the distribution of early life stages, should take us closer to resolving this puzzle. Anchovy Engraulis encrasicolus (L.), as a small pelagic fish species, is generally well-known as an extremely important component of the marine ecosystem either viewed from an eco- logical or an economic perspective. This coastal euryhaline pelagic fish species is a batch spawner that has a protracted spawning season. In the Adriatic, its spawning takes place near the coast within quite wide ranges of temperature (11.6–27.6°C) and salinity (9.1–39.6) (Regner, 1996). Spawning of anchovy in this study area lasts from early spring to late summer, peaking from April to July (Zorica et al., 2013). Its eggs are pelagic and frequently found in the plankton from April to September, with a peak in June–July, and sometimes from March to December (Vučetić, 1964; Varagnolo, 1965; Zavodnik, 1970; Piccinetti et al., 1980; Regner, 1985; Palomera, 1992; Regner, 1996; Zorica et al., 2014; Mandić et al., 2015). Consequently, its early life stages can be found in that period, more or less distributed along the Adriatic con- tinental shelf. By the time spawning is completed and sea temperatures decrease, adults start to migrate towards open seawaters, forming large shoals (Vučetić, 1964; Piccinetti, 1970; Regner, 1972; Gamulin & Hure, 1983; Sinovčić, 2000). In contrast, juveniles mainly remain closer to the coast until winter or until the time they reach first sexual maturity (Betulla Morello & Arneri, 2009). In the eastern part of the Adriatic, anchovy is mainly caught with purse seiners that use light to attract and aggregate the fish near the surface (Cingolani et al., 1996; Kraljević et al., 2014). Although the eastern Adriatic coast fisheries generally show a higher preference for sardine (Kraljević et al., 2014), in the last 10 years, probably due to changes in the market, fishermen tend to fish anchovy as well. So, in the last 10 years its official catches show a slightly increasing trend (STECF, 2013). Although some investigations concerning the distribution pattern of anchovy early life stages in the Adriatic Sea have been presented by Betulla Morello & Arneri (2009), many para- meters need to be determined to complement the information that in future could be used as a diagnostic tool for fishery sustainability. Hence, the purpose of this study is to describe the https://doi.org/10.1017/S0025315418001145 Downloaded from https://www.cambridge.org/core. University of Winnipeg, on 02 Jan 2019 at 09:57:28, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms.