Category: Fish/Shellfish Research
Author(s): Kirk L. Krueger, Kenneth B. Pierce, Jr., Timothy Quinn, and Daniel E. Penttila
The shoreline of Puget Sound provides habitat for many species, including surf smelt (Hypomesus pretiosus) and Pacific sand lance (Ammodytes hexapterus); two fishes that spawn in the intertidal zone. Surf smelt and Pacific sand lance (hereinafter sand lance) are key parts of the Puget Sound food web (Simenstad and others, 1979), providing food for many sea birds, marine mammals and fishes, including economically and culturally important Pacific salmon (Oncorhynchus spp.). By integrating climate change predictions and their expected effects on intertidal geological processes and subsequent ecological processes, we hope to inform policies to protect surf smelt and sand lance spawning habitat while addressing legitimate private property concerns regarding shoreline armoring.
Shoreline armoring might be the most important threat to surf smelt and sand lance spawning habitat (Thom and others,1994), and a little studied threat to sand lance winter rearing habitat (Quinn, 1999). Griggs and others (1994) and Williams and Thom (2001) identify many detrimental effects of shoreline armoring, and more than one-third of Puget Soundâ€™s shoreline is armored (Puget Sound Water Quality Action Team, 2002), including many locations where surf smelt and sand lance spawn. Since 1974 shoreline armoring has been regulated where spawning has been documented. However, many beaches have not been surveyed and the spawning behavior of sand lance was not well known until 1989 (Penttila, 1995), so much of the shoreline of Puget Sound was armored prior to regulation or documentation of beach spawning. Furthermore, existing regulations do not consider cumulative or off-site impacts of armoring, cannot prohibit armoring in most cases (see Carman and others, 2010), and do not address likely future environmental conditions such as higher sea level.
Sea level is expected to rise substantially in this century, which likely will profoundly affect the structure and function of the Puget Sound ecosystem (National Wildlife Federation, 2007). As sea level rises the spatial extent of intertidal beaches might contract, which would reduce the extent of intertidal habitat and thus the amount of suitable spawning habitat. Where the upward extent of beach migration is limited by shoreline armoring (Griggs and others, 1994; Griggs, 2005), loss of spawning habitat might be exacerbated (Thom and others, 1994). However, the question of whether sea level rise will result in a loss of surf smelt and sand lance spawning habitat on armored shorelines has not been addressed quantitatively. Our goals were (1) to describe the geographic and temporal distribution of surf smelt and sand lance spawning in Puget Sound, including discontinuities in occurrence and egg abundance; (2) to describe associations between beach elevation and egg abundance; and (3) to determine the potential for spawning habitat contraction and egg loss as a result of sea level rise on armored beaches.
In this paper, we address our goals by describing some results and conclusions (1) of a long-term survey to detect beach spawning in Puget Sound, (2) of a one-year survey of beach spawning density on Camano Island, WA, and (3) of the first year of a study of the spatial distribution of eggs on central Puget Sound intertidal beaches.