Food resource partitioning between three sympatric fish species in Porsangerfjord, Norway

Abstract

Understanding predator-prey relationships and resource overlap between sympatric species is fundamental for enhanced scientific knowledge and management. This study compared the trophic ecology of three small demersal fishes (Artediellus atlanticus, Myoxocephalus scorpius, and Leptagonus decagonus) using stomach data and stable isotope analyses. All fish were sampled during 2009-2011 from the inner basin of Porsangerfjord (70°N, 25°E) in northern Norway. The dominant prey found in A. atlanticus was polychaetes, while M. scorpius had fed on juvenile fishes and decapods, and L. decagonus had mainly consumed copepods. The trophic positions of the fishes overlapped extensively (A. atlanticus: trophic level (TL) 3.4-4.2; M. scorpius: TL 3.6-4.3; L. decagonus: TL 3.7-4.6). Although the nutritional origin (d 13 C) of the prey varied among the fishes, A. atlanticus and M. scorpius were associated with benthic prey (d 13 C -18.64 to -17.28 and d 13 C -18.67 to -17.04, respectively), whereas L. decagonus was associated with pelagic prey (d 13 C -19.95 to -18.74). The combined results of the stomach data and stable isotope analyses further suggested that M. scorpius had a dietary preference for benthic-pelagic prey. Thus, the fish diets were considered to be species specific, and the study indicated that the three species utilize different prey groups within the food web of the Porsangerfjord ecosystem.

Movement types of an Arctic benthic fish, shorthorn sculpin (Myoxocephalus scorpius), during open-water periods in response to biotic and abiotic factors

“…Although Shorthorn Sculpin have been documented with pelagic and demersal fishes in their gut contents (Kallgren et al 2014;Cardinale et al 2000) with some evidence that they feed on Arctic Cod (Dick et al 2009;Landry et al 2016) the results from this study are inconclusive regarding whether Shorthorn Sculpin actively prey on Arctic Cod, or scavenge them. The change in MTs in zone 1, a decrease in MT1 and increase in MT2, may be a result of Arctic Cod presence considering they occurred in much higher abundances and more often in zone 1 than in zones 2 and 3.…”

“…Shorthorn Sculpin are benthic and can reach a size of 30 cm, with a wide distribution from temperate to Arctic waters (Robins & Ray 1986). Their diets consist mainly of benthic invertebrates (Cui et al 2012), however, some juvenile and adult fishes have been identified in Shorthorn Sculpin stomachs (Kallgren et al 2014;Cardinale et al 2000), and stable isotope analysis has found that these fish couple benthic and pelagic energy pathways with as much as 50% of their consumed carbon coming from pelagic sources (McMeans et al 2013;Landry et al 2016). One study on the southern end of Baffin Island found Arctic Cod in the gut contents of Shorthorn Sculpin (Dick et al 2009).…”

Effects of the invasive red king crab on food web structure and ecosystem properties in an Atlantic fjord

“…The value of P/B was set equal to that for small cod (1.20 year -1 ), while Q/B was set to 6.0 year -1 and was equal to the value used for small cod in the Sørfjord model (Pedersen et al 2008). The most common species in this group in Porsangerfjorden were shorthorn sculpin (Myoxocephalus scorpius) and Atlantic hookear sculpin (Artedillus atlanticus) (Källgren et al 2015). Shorthorn sculpin were distributed in the upper subtidal in all areas of the fjord and were also common at deeper water in the inner two subareas (4E and 4W).…”

What determines prey selection in owls? Roles of prey traits, prey class, environmental variables, and taxonomic specialization

“…Separation between predatory species in the food niche dimension has been studied extensively in the ecological literature (e.g., Schoener, and references therein; Kamler, Stenkewitz, Klare, Jacobsen, & Macdonald, ; Domingo, Domingo, Badgley, Sanisidro, & Morales, ; Symes, Wilson, Woodborne, Shaikh, & Scantlebury, ; Sheremetev, Rozenfeld, Dmitriev, Jargalsaikhan, & Enkh‐Amgalan, ; Källgren, Pedersen, & Nilssen, ), and a general pattern of increased prey size with increasing predator size has been recognized, for example, in numerous guilds of birds, carnivorous mammals, lizards, wasps, flies, beetles, and marine predators (e.g., Hespenheide, and references therein; Cohen, Pimm, Yodzis, & Saldaña, ; Carbone, Mace, Roberts, & Macdonald, ; Brose et al., ; Costa, ; Nakazawa, and references therein). However, numerous factors affect actual prey intake, including prey availability, the environment, and intensity of competition (e.g., Herrera & Hiraldo, ; Kappes, Weimerskirch, Pinaud, & Le Corre, ; Levesque, Juniper, & Marcus, ; Luiselli, ; Tsuruta & Goto, ).…”