Diet of non‐native northern snakehead (Channa argus) compared to three co‐occurring predators in the lower Potomac River, USA

Abstract

– Introductions of large, non‐native, carnivorous fishes continue to occur worldwide and represent a substantial management concern to global biodiversity. One of the most recent non‐native fishes to successfully establish in North America is the northern snakehead (Channa argus), found in the lower Potomac River catchment. Dispersal of the northern snakehead throughout this system has been well documented since its original discovery in May 2004; however, little is known about the foraging habits of this species and its interactions with co‐occurring predators. Here, we quantify northern snakehead diet in comparison with the diets of naturalised largemouth bass (Micropterus salmoides), and native American eel (Anguilla rostrata) and yellow perch (Perca flavescens) collected from tidal freshwaters bordering Virginia and Maryland near Fort Belvoir, Virginia. Over 97% of northern snakehead gut contents were fishes, with fundulid and centrarchid species consumed most frequently. Dietary overlap was biologically significant only between northern snakehead and largemouth bass. Aquatic invertebrates were >10 times more common in native predator diets, reducing dietary overlap with northern snakehead. Ontogenic shifts in adult northern snakehead diet were also detected, which may be explained by optimal foraging rather than true prey specificity. Northern snakehead may be occupying a novel niche based on a piscivorous diet, therefore limiting competition with resident predators in the lower Potomac River. Further research into interactions between largemouth bass and northern snakehead is needed to inform management decisions and understand the ecological impacts of this non‐native species.

The First International Snakehead Symposium: News from the Front(s)

“…Optimum temperature for growth was 30.3°C for juveniles and 26.1°C for adults suggesting summer temperatures in many southeastern U.S. and mid-Atlantic waters may be exacting increased metabolic respiration cost as suggested by Gascho Landis et al (2011). These findings were similar to those of Saylor et al (2012) and implied that Northern Snakehead were opportunistic feeders consuming food items most commonly encountered in their habitats. These findings were similar to those of Saylor et al (2012) and implied that Northern Snakehead were opportunistic feeders consuming food items most commonly encountered in their habitats.…”

Identification and Location of Testes in the InvasiveChanna argusCantor (Northern Snakehead)

“…According to Odenkirk and Owens (2007), food items observed in the stomachs of 219 northern snakehead collected from the Potomac River between 2004 and 2006 consisted mostly of banded killifish (Fundulus diaphanous), white perch (Morone americana), bluegill (Lepomis macrochirus), and pumpkinseed sunfish (Lepomis gibbosus). Saylor et al (2012) found similar food habits among northern snakehead in the Potomac River with similar fish species consumed most frequently and non-fish taxa consumed rarely. In the Syr Dar'ya basin of central Asia, Dukravets and Machulin (1978) reported that northern snakehead fed on 17 species of fish, including species that measured up to 33 percent of the predator's total body length.…”

Using Scenarios to Assess Possible Future Impacts of Invasive Species in the Laurentian Great Lakes

“…Northern Snakehead is an obligate air-breather and can therefore survive in poorly oxygenated water such as shallow ponds and swamps (Courtenay and Williams 2004). It feeds almost entirely on fish (Saylor et al 2012). In the USA, it has spread primarily through intentional or accidental release.…”

“…Both parents guard their eggs and newly hatched larvae in a floating nest. Workshop participants agreed on a number of foundational assumptions that would influence the types of effects that this species would have if it were to become established in the Great Lakes (Courtenay and Williams 2004;Herborg et al 2007;Saylor et al 2012):…”