Burrowing behavior, habitat, and functional morphology of the Pacific sand lance (Ammodytes personatus)

Abstract

Abstract-The Pacific sand lance (Ammodytes personatus) is a small, elongate forage fish that spends much of its life buried in the seafloor. We determined that the Pacific sand lance can burrow in a wide variety of sediments from silt to gravel, but it prefers coarse sand (0.50-1.00 mm grain size). In the absence of coarse sand, the Pacific sand lance chooses larger grain sizes over smaller ones. These preferences are independent of light or the compaction of sediment, and therefore indicate that visual cues and ease of entry are not primary means of choosing burial substrate. Instead, we speculate that the Pacific sand lance is morphologically adapted for rapid mobility in coarse sand and that coarse sand has enough interstitial spaces to enable respiration during protracted immersion. As an obligate burrower in specific sediments, the Pacific sand lance is a good candidate for habitat-based management. Substrate maps of 3 fishing grounds in southeast Alaska where the Pacific sand lance is abundant and where habitat-based management is practiced were used to create potential habitat maps. Different geologic histories have resulted in variable amounts of preferred (sand-gravel), suitable (sand mixed with silt, cobble-boulder, or rock outcrop), and unsuitable (mud, pebble-boulder) habitat for this species among regions.

Characteristics and Dynamics of a Large Sub-Tidal Sand Wave Field—Habitat for Pacific Sand Lance (Ammodytes personatus), Salish Sea, Washington, USA

“…Several studies of PSL and sand-eel habitats show that these fish prefer sand habitats consisting of medium-to coarse-grained sand of 0.25 to 1 mm in size [8,11,14,18,38], and our results show that PSL select bottom sediment between 0.25 to 0.71 mm in the San Juan Channel sand wave field. Experimental studies (e.g., [38,39]) also show that PSL prefer this range of sediment grain sizes.…”

“…Experimental studies (e.g., [38,39]) also show that PSL prefer this range of sediment grain sizes. Furthermore, our results and others (as cited above) show an absence of PSL if the sediment contains more than a few percent (~5%) of fines (fine sand + silt + clay-size material; Figure 14).…”

Diet and feeding observations from an unusual beluga harvest in 2014 near Ulukhaktok, Northwest Territories, Canada

“…Interviewees observed Arctic char and sand in the stomachs of the whales; however, interviewees did not share observations about beluga feeding from the ocean floor. The presence of sand in the stomachs of beluga is consistent with a diet that included Sandlance, as this species of forage fish is known to burrow in the seafloor (Bizzarro et al 2016). One participant observed beluga whales eating small fish and Arctic Char at the mouth of the Kaylihok River (P. Ekpakohak).…”

Increased sediment load during a large-scale dam removal changes nearshore subtidal communities

“…Observations of sand lance by divers were infrequent near the Elwha River mouth prior to dam removal, but afterwards were common in or near newly deposited sand ( Fig 12 ). Median grain size of the new sand east of the river mouth averaged 0.45 mm (sites D1, E1 and F1; S4 Table ), nearly within the grain size range (0.5–1.0 mm) preferred by sand lance for burrowing [ 118 ]. Interestingly, though, sand lance were not observed on the pre-dam removal sand deposit west of the mouth ( Fig 12 ) even though grain size was similar (mean of median at sites C1 and C2 = 0.46 mm in 2012, before deposition of mud occurred; S4 Table ).…”