445 NOAA First U.S. Commissioner National Marine Fishery Bulletin established 1881 of Fisheries and founder Fisheries Service of Fishery Bulletin Abstract—The Pacific sand lance (Ammodytes personatus) is a small, Burrowing behavior, habitat, and functional elongate forage fish that spends morphology of the Pacific sand lance much of its life buried in the sea- floor. We determined that the Pa- (Ammodytes personatus) cific sand lance can burrow in a wide variety of sediments from silt 1 to gravel, but it prefers coarse sand Joseph J. Bizzarro (contact author) (0.50–1.00 mm grain size). In the Ashley N. Peterson2 absence of coarse sand, the Pacific Jennifer M. Blaine3 sand lance chooses larger grain sizes 2 over smaller ones. These preferences Jordan P. Balaban are independent of light or the com- H. Gary Greene4 paction of sediment, and therefore Adam P. Summers4 indicate that visual cues and ease of entry are not primary means of Email address for contact author: [email protected] choosing burial substrate. Instead, we speculate that the Pacific sand 1 School of Aquatic and Fishery Sciences 3 Washington Department of Fish and lance is morphologically adapted University of Washington Wildlife for rapid mobility in coarse sand Box 355020 600 Capitol Way N. and that coarse sand has enough Seattle, Washington 98195-5020 Olympia, Washington 98501 interstitial spaces to enable respira- Present address: Center for Habitat Studies 4 tion during protracted immersion. Friday Harbor Laboratories Moss Landing Marine Laboratories As an obligate burrower in specific University of Washington 8272 Moss Landing Road sediments, the Pacific sand lance is 620 University Road Moss Landing, California 95039 a good candidate for habitat-based Friday Harbor, Washington 98250 management. Substrate maps of 3 2 Department of Ecology and Evolutionary Biology Kingston, Rhode Island 02881 fishing grounds in southeast Alas- University of California, Irvine ka where the Pacific sand lance is 321 Steinhaus Hall abundant and where habitat-based Irvine, California 92697 management is practiced were used to create potential habitat maps. Different geologic histories have re- sulted in variable amounts of pre- ferred (sand–gravel), suitable (sand Burrowing presents biomechanical collapses behind them. The terres- mixed with silt, cobble–boulder, or and ecological challenges but enables trial equivalent of this behavior is rock outcrop), and unsuitable (mud, access to expanded trophic oppor- seen in the “sand-swimming” skink pebble–boulder) habitat for this spe- tunities and protection from many species (Mushinsky and Gans, 1992; cies among regions. predators. The selective pressures Maladen et al., 2011). Penetrating surrounding burrowing are expressed friable substrates in a completely in the morphological features of bur- aqueous environment is fundamen- rowing animals, as in the stout fore- tally different from terrestrial sand arms of moles and armadillos and in swimming by virtue of the density of the heavily reinforced skull of caeci- water and its potential contribution lians and dibamids (Kleinteich et al., to the excavation process. 2012; Rose et al., 2013). A subterra- The Pacific sand lance (Ammodytes nean lifestyle is uncommon for aquat- personatus) is an elongate, burrowing ic vertebrates but has been observed forage fish with a wide distribution in Manuscript submitted 11 November 2015. in a taxonomically diverse group the eastern North Pacific and a his- Manuscript accepted 3 August 2016. of marine fish taxa. Flounders and tory of taxonomic confusion. Only A. Fish. Bull: 114:445–460 (2016). skates routinely cover themselves in hexapterus, formerly the Pacific sand Online publication date: 25 August 2016. substrate; jawfishes, tilefishes, and lance and now assigned the common doi: 10.7755/FB.114.4.7 garden eels excavate permanent bur- name of Arctic sand lance (Orr et al., The views and opinions expressed or rows; and some fishes (e.g., Pacific 2015), and A. personatus were con- implied in this article are those of the sandfish, Trichodon trichodon; sand sidered historically as valid North author (or authors) and do not necessarily lances, Ammodytes spp.) spend a ma- Pacific species, but the number of reflect the position of the National jority of their life beneath the sub- Ammodytes species in the North Pa- Marine Fisheries Service, NOAA. strate after creating a tunnel that cific region and the extent of their 446 Fishery Bulletin 114(4) distributions have long been debated (Ohshima, 1950; burrowing requirements of the Pacific sand lance are Han et al., 2012; Turanov and Kartavtsev, 2014). Recent necessary steps toward the development of ecosystem genetic and morphological evidence has resolved this is- approaches to the management of this species. sue and indicates the presence of 2 additional congeners Like the sandfish (Scincus scincus), a lizard found (Orr et al., 2015). Furthermore, the only species with an in sandy habitats in North Africa and Southwestern expansive eastern North Pacific distribution, formerly Asia (Maladen et al., 2009), the Pacific sand lance is considered to be A. hexapterus, was redescribed as A. able to burrow rapidly into the substrate (Gidmark et personatus (Orr et al., 2015). The range of A. personatus al., 2011). It is tempting to suppose that this fish takes was established from southern California to the western advantage of the viscosity and density of water to stir, Aleutian Islands and may extend to the Sea of Okhotsk or fluidize, the sand before burrowing; however, this in the western Pacific (Mecklenberg et al., 2011; Orr behavior has not been observed. Instead, high-speed et al., 2015). Ammodytes personatus mainly occurs in video of Pacific sand lance burrowing in the laboratory coastal intertidal and subtidal waters but has been re- indicates that this fish dives headfirst into the sand, ported at depths of 172 m (Love et al., 2005). beating its tail and driving the head and anterior two- The Pacific sand lance is a source of energy trans- thirds of its body underground. At this point, the bur- fer between secondary producers and upper-trophic- ied part of its body undulates and draws the remaining level species and pelagic and benthic regions because part of the fish beneath the sediment (Gidmark et al., it grazes on zooplankton in the water column and has 2011). Models show that the sandfish uses substan- an obligate affiliation with sediments. The structure tial force to burrow into dry sand. It is not possible to and dynamics of nearshore ecosystems are heavily in- extrapolate this type of movement to the Pacific sand fluenced by the biomass of forage fishes (Gaichas et al., lance because there are no data to indicate the relative 2010), and species of Ammodytes, including the Pacific ease of penetrability through dry sand and sand inun- sand lance, are of vital importance for the energetics dated with water. Results from isolated laboratory and and breeding success of a variety of marine mammals field studies, however, indicate that burial preferences (Weinrich et al., 1997), seabirds (Curry et al., 2011), range from fine to very coarse sands (Pinto et al., 1984; and fishes (Arnott et al., 2002). For instance, hump- Haynes et al., 2007; Robinson et al., 2013). If these back whales (Megaptera novaeangliae) at Stellwagon burial preferences can be refined further through more Bank, Massachusetts, excavate bottom sediments at complete testing, this information could 1) be used in night to forage on dense aggregations of buried sand habitat-based management plans for Pacific sand lance lances (Ammodytes spp.) (Friedlander et al., 2009). Off and 2) may reveal morphological and behavioral adap- British Columbia, growth rates of rhinoceros auklet tations that explain the preference of Pacific sand lance (Cerorhinca moncerata) chicks are positively corre- for a particular grain size or sizes. lated with abundance of Pacific sand lance (Bertram The Pacific sand lance is an accomplished burrower and Kaiser, 1993). Several groundfishes (e.g., starry that spends a large percentage of its time in sediment flounder [Platichthys stellatus]; great sculpin [Myoxo- of unknown characteristics. Because it is an impor- cephalus polyacanthocephalus] have been reported to tant forage fish with a strong benthic association, the feed on schools of Pacific sand lance as they move from habitat preferences of this species has direct implica- foraging to burial grounds off southeast Alaska (Hob- tions for the development of ecosystem approaches to son, 1986). management and conservation. This fish is also an ex- Where species of Ammodytes are exploited in com- cellent model for studying locomotion by an elongate, mercial fisheries, the associated loss of forage bio- anguilliform burrower in an aquatic environment. The mass can have ecosystem-level effects. In the North goals of our study were fivefold: 1) to assess the grain Sea, overfishing of the sand eel (A. marinus) has been sizes, ranging from silt to very fine gravel, that are po- linked to poor breeding success of several seabird spe- tential burial habitats for Pacific sand lance; 2) to de- cies (Arnott et al., 2002), and the prosecution of a termine whether Pacific sand lance prefer substrates of fishery for the sand eel has negatively impacted the a particular size; 3) to use lighting and sediment com- breeding productivity of the population of black-legged paction to gain insight into the factors that favor the kittiwake (Rissa tridactyla) (Frederiksen et al., 2008). selection of a burial substrate; 4) to use field sampling Conversely, an abundance of Ammodytes species can and habitat mapping to link sediment preferences of enhance the productivity and efficiency of groundfish the Pacific sand lance in the laboratory with substrate fisheries. For instance, when biomass of Ammodytes associations in the field; and 5) to reveal specialized species is relatively high, Atlantic cod (Gadus morhua) morphological features for burrowing. form feeding aggregations in small, predictable areas (i.e., over burial habitat) where they can be targeted easily (Richardson et al., 2014).