Feeding and ecomorphology of three clupeoids in the N Aegean Sea

Abstract

This study examines the feeding habits of anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and round sardinella (Sardinella aurita). The results are combined with previously published information on feeding-related morphological features (i.e. mouth area, intestine length and tail area) in order to explore morphological affinities between species and the effect of ecomorphology on their co-existence. These species were mainly zooplanktivorous and no dietary differences were found with sex and season. Anchovy preyed mainly on Crustacea larvae, whereas sardine and round sardinella on Copepoda. In the majority of cases (>90%), the individual fractional trophic level of all species ranged between 3.0 and 3.5, classifying them as omnivores with preference to animals. The feeding-related morphological features differed between anchovy and the two other species, whereas only intestine length differed between sardine and round sardinella. The fact that the diet and morphology of round sardinella show a greater resemblance to those of sardine further supports the hypothesis that round sardinella is a particulate feeder, as is sardine. Hence the three species tend to exploit the same food resources differently throughout the year. Thus, they make best use of the environment and its resources, in order to avoid competition and achieve optimum feeding conditions throughout their life cycles.

Patterns of trace metal bioaccumulation and trophic transfer in a phytoplankton-zooplankton-small pelagic fish marine food web

“…reported in the GoL byPethybridge et al (2014), or byKarachle and Stergiou (2014) in another area of the Mediterranean Sea (Agean Sea), suggesting that the contaminant variations we found are probably not related to differing diets. Other factors such as substantial contaminant elimination through reproduction (i.e.…”

Assessment of mercury and cadmium via seafood consumption in Italy: estimated dietary intake (EWI) and target hazard quotient (THQ)

“…That is, the fish that are high on the trophic level might be expected to concentrate higher levels of bioaccumulative metals as Hg and the same was found in this study for swordfish and bluefin tuna, typical high-order marine predators. In the same way, in accordance with feeding spectra, anchovies and sardines feeding mainly on water plants and plankton (Karachle & Stergiou 2014) contained significantly lower levels of Hg (p = 0.05) than fish as European conger eel, long-nose skate, common sole and black belly rosefish, whose diet consisting largely of fishes (Stergiou & Karpouzi 2002) reflected a major metal content. Moreover, the low levels observed in anchovies and sardines could also be habitat effect, they being surface feeders and, thus, exposed to lower contamination levels than demersal and benthic counterparts (Storelli et al 2006).…”

Environmental effects on the spatio‐temporal patterns of abundance and distribution of Sardina pilchardus and sardinella off the Mauritanian coast (North‐West Africa)

“…A recent study based on a combined analysis of ecomorphology and trophic position showed that sardine and sardinella from the North Agean Sea have a greater resemblance and exploit the same food resources differently (Karachle and Stergiou, ). In the Mauritanian waters, sardine and sardinella feed mainly on phytoplankton, copepods and detritus (Gushchin and Corten, ).…”

“…The ability to switch between these feeding modes makes this species highly opportunistic, being able to maximize its energy intake by employing the most appropriate feeding mode for a particular food environment. In addition, sardine had a shorter intestine compared to that of sardinella and displays a more protractile mouth that might be more advantageous in the case of particulate feeding (Karachle and Stergiou, ). Species with lengthier guts achieve optimum nutrient and energy gain from the food consumed suggesting that sardinella is more efficient than a sardine in terms of energy gain from the food consumed.…”