Effect of habitat conditions on reproduction of the European anchovy (Engraulis encrasicolus) in the Strait of Sicily

Abstract

The aims of this study were to describe the reproductive cycle of the European anchovy (Engraulis encrasicolus) off the south coast of Sicily and determine whether intra-and inter-annual reproductive trait variations, if any, are adaptive responses which maximize reproductive success under environmental fluctuations. Biological data were collected from purse seine and mid-water pelagic trawl commercial catches landed in Sciacca (Sicily) over 6 yr (1997)(1998)(1999)(2000)(2001)(2002) at fortnightly intervals, analysing a total of 84 581 individuals. No inter-annual changes in length at first reproduction were observed, with a mean pooled value of 11.26 cm for both sexes being found. Spawning intensity, indicated by gonadosomatic index, condition factor and length-weight relationships, seem to be governed by food availability prior to spawning. Anchovy reproductive investment was limited by the area's low primary production. There was a synchrony between reproductive cycle and temperature. Water warming marks the onset of a period of high water stability in the area, and its later cooling marks the onset of a period with low water stability. The relationship between reproductive cycle and temperature is therefore probably a reproductive strategy having evolved to ensure that spawning takes place during the period of the year when water column stability is higher, favouring food concentration and egg and larval retention in the spawning areas.

Effect of intra‐specific competition, surface chlorophyll and fishing on spatial variation of gadoid's body condition

“…However, it played a key role on the body condition of gadoids analyzed, consistent with previous studies in the Mediterranean (e.g., Basilone et al 2006, Rueda et al 2014). Due to the high degree of oligotrophy in the Balearic Islands, chlorophyll a concentration had been proved to be crucial for the persistence of fish populations in the area with a high recruitment dependence on favorable trophic conditions in terms of fish survival and condition ).…”

“…For example, intra-specific competition has shown opposite influences on body condition, from positive (Orlova et al 2010, Kjesbu et al 2014) to negative (Casini et al 2006, Sandeman et al 2008 or not significant (Carscadden andFrank 2002, Kjesbu et al 2014). The effect of surface chlorophyll a is often positive (Basilone et al 2006, Rueda et al 2014, though its influence is observed at different temporal lags (Hidalgo et al 2008, Rueda et al 2014). In addition, several authors described a negative effect of fishing on body condition (e.g., Choi et al 2004, Hiddink et al 2011, Lloret et al 2014, whereas others have detected positive effects at low levels of fishing pressure (Giacalone et al 2010) or absence of a statistical significant relationship Planes 2003, Giacalone et al 2010).…”

Changes in size at maturity of European hake Atlantic populations in relation with stock structure and environmental regimes

“…The impact of temperature on fish physiology and behavior has been documented for several species. Many studies have described the effects of sea temperature on fish metabolism (Tyler and Colow, 1985;Solemdal, 1997;Martínez et al, 1999;Harvey, 2005;Stevens et al, 2006), growth rates (Rätz et al, 1999;Dutil et al, 2003), condition (Krohn et al, 1997), reproduction (Fedorov, 1971;Wootton, 1990;Jonsson and Jonsson, 2003;Privalikhin, 2003;Basilone et al, 2006;Coombs et al, 2006) or offspring survivorship (Lambert et al, 2003;O´Brien et al, 2003;Abdoli et al, 2005). Furthermore, water temperature also conditions fish population dynamics (Marshall et al, 2000;Armstrong et al, 2004;Yoneda et al, 2006) and distributions (Louge, 1996;Gordoa et al, 2000;Pájaro et al, 2005).…”

Female reproductive cycle and batch fecundity in the central-southern Adriatic population ofEngraulis encrasicolus(Osteichthyes: Engraulidae)

“…• C, in the Adriatic Sea (authors' personal observations), the increase in temperature being the main factor triggering gonad development and spawning (Sanz & Uriarte 1989;Motos 1996;Basilone et al 2006). In the present study, the steady increase from May to July of the anchovy batch fecundity may be related to the SST increase in these months, from 19.0 to 25.4…”