DNA metabarcoding suggests dietary niche partitioning in the Adriatic European hake

Abstract

The Northern Adriatic Sea (FAO Geographical Sub-Area 17) is one of the most productive fishing areas of the Mediterranean Sea and it includes a broad diversity of habitats. In the Northern Adriatic basin, the Pomo Pit (200–273 m of depth) is one of the most important areas of aggregation for some demersal stocks shared in the Adriatic Sea and it is an important spawning/nursery area of the European hake (Merluccius merluccius). Through a metabarcoding approach we investigated the feeding habits of European hake, both inside and outside the Pomo Pit, and their temporal variability comparing samples collected in 2016 and 2014. Our analyses proved the presence of an ontogenetic shift from a diet based mainly on crustaceans in juveniles to a more piscivorous feeding behaviour in adult hakes and suggested the presence of a specific niche partitioning and food preferences between hakes living inside and outside the Pomo Pit. The main differences among adult hakes refer to the presence of molluscs in the stomachs of hakes collected within the Pomo Pit and the presence of high depth prey species (i.e., Micromesistius poutassou). Metabarcoding revealed the relevant ecological role played by the Pomo Pit in M. merluccius feeding behaviour and ontogenetic development, promoting a careful ecosystem-based management of fisheries in this area through focused conservation measures.

Time-Scale Analysis of Prey Preferences and Ontogenetic Shift in the Diet of European Hake Merluccius merluccius (Linnaeus, 1758) in Southern and Central Tyrrhenian Sea

“…According to previous literature for this and other geographical areas [15][16][17][18]20,21,51,69,72,82], the prey composition in the other ontogenetic classes have confirmed the transition of European hakes during their growth to a diet mainly based on teleost and decapod consumption (mainly after the first year of age, TL > 15 cm). This tendency is reported by results for all the years, with a similar diet composition among hakes belonging to Class II, mainly based on small teleost, as mesopelagic bioluminescent prey (e.g., C. maderensis, M. muelleri), Euphasiids, and larger nektobentic species (such as B. boops, E. encrasicolus, Trachurus sp., C. agassizi, A. sphyrena) in the other size classes, with an increase in pelagic and benthopelagic decapod consumption (P. longirostris, S. membranacea, Pasiphae sp., C. crassicornis) in Classes III and IV.…”

“…Another interesting aspect shown by the results was the low occurrence of cephalopod prey in hake diet composition if compared with literature from other geographical areas, such as the Adriatic Sea and the Strait of Sicily [18,20,82]. This could be mainly related to the ecological features of GSA 10, characterized by a high occurrence of mesopelagic bioluminescent fishes, benthopelagic and mesopelagic crustaceans, and small pelagic species, which may be preferred as prey compared to cephalopods.…”

“…Several studies are required to deepen the knowledge on the population dynamics of prey species, adding new information on their temporal and spatial distribution. Further analysis supported by innovative molecular and stable isotopes techniques are required to deepen the knowledge on the importance of different teleost species in hakes and other benthopelagic predators' diets [18,72,82]. These are essential to confirming diet composition, and avoiding the problems related to a high degree of digestion of prey parts, which reduces identification accuracy, causing an inevitable underestimation of the different species.…”

Recent molecular techniques to strengthen ecological studies in echinoderms

“…This method provides a comprehensive and efficient approach to studying the biodiversity and ecological patterns of echinoderms, aiding in conservation efforts, and informing ecosystem management strategies (Leray & Knowlton, 2015;Leray et al, 2013;Riccioni et al, 2022). DNA metabarcoding, a high-throughput sequencing technique, has revolutionized the field of biodiversity assessment and ecological studies (Barnes & Turner, 2016).…”

Feeding Selectivity and Diet Shift of Protosalanx chinensis during Spring in Lake Dalong, Northeastern China

“…Meanwhile, the diet shift of fish also drastically occurs during the zooplanktivorous larvae and juvenile stage, probably corresponding with the increased feeding ability resulting from enlargement of the mouth, increased swimming ability, and development of sense organs [11,12]. Exploring the diet shift of a dominant fish in a certain community is essential to deepening the knowledge concerning the prey-predator interactions and the role of habitat in the feeding habits of the fish, all of which is important to understanding trophic network dynamics and managing fisheries sustainably [13][14][15].…”