Seasonal meso‐ and microhabitat selection by the northern snakehead (Channa argus) in the Potomac river system

Abstract

Lapointe NWR, Thorson JT, Angermeier PL. Seasonal meso‐ and microhabitat selection by the northern snakehead (Channa argus) in the Potomac river system. Ecology of Freshwater Fish 2010: 19: 566–577. © 2010 John Wiley & Sons A/S Abstract – The northern snakehead (Channa argus) is a large piscivorous fish that is invasive in eastern Europe and has recently been introduced in North America. We examined the seasonal habitat selection at meso‐ and microhabitat scales using radio‐telemetry to increase understanding of the ecology of this species, which will help to inform management decisions. After the spawning season (postspawn season, September–November), northern snakeheads preferred offshore Eurasian water‐milfoil (Myriophyllum spicatum) beds with shallow water (∼115 cm) and soft substrate. In the winter (November–April), these fish moved to deeper water (∼135 cm) with warmer temperatures, but habitat selection was weak at both scales. Northern snakeheads returned to shallower water (∼95 cm) in the prespawn season (April–June) and used milfoil and other cover. Habitat selection was the strongest at both meso‐ and microhabitat scales during the spawning season (June–September), when fish preferred macrophytes and cover in shallow water (∼88 cm). Our results help to identify habitats at the risk of invasion by northern snakeheads. We suggest that control efforts and future research focus on shallow waters, and take into consideration the seasonal habitat preferences.

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

“…For example, demographic models have shown that removal of northern snakehead should occur during pre-spawn periods or prior to juvenile dispersal in order to be the most efficient in limiting population growth (Jiao et al, 2009). This is also the time period when northern snakehead are more easily captured by electrofishing due to limited movement of adults (Lapointe et al, 2010). Furthermore, snakehead appear to be most active during peak daylight times, suggesting targeted removal should occur during early morning or late evening hours when fish are less active.…”

“…During the post-spawn period, from September to November, snakehead were found in offshore habitats with vegetative cover such as Eurasian milfoil and hydrilla. However, during winter, snakehead preferred offshore habitats with deep water (Lapointe et al, 2010).…”

“…In the Potomac River, northern snakehead are typically found in shallow water with floating and emergent vegetation (Odenkirk and Owens, 2005;Lapointe et al, 2010). They have a broad temperature range of 32 -90 °F (0 to 31°C) (Okada, 1960) and as high as 104 °F (40°C) in water without oxygen (Frank, 1970;Nikol'skii, 1961).…”

“…In 2006, Lapointe et al (2010) radio-tagged adult northern snakehead in Virginia tributaries of the Potomac to determine seasonal habitat selection. They found that snakehead in the Potomac tributaries generally preferred shallow habitats that provided cover.…”

Anthropogenic Disturbances in Estuarine Ecosystems: The Effects of Altered Freshwater Inflow, Introduction of Invasive Species, and Habitat Alteration in the Loxahatchee River, FL

“…Understanding how individuals within a population of invasive organisms move following initial recruitment has a number of implications related to long term dispersal, as well as control and eradication (Brown et al 2006;Cookingham and Ruetz 2008;Lapointe et al 2010;Vrieze et al 2011). …”