Summary of Coastal Intertidal Forage Fish Spawning Surveys: October 2012 – September 2013

Categories:

Published: February 2013

Pages: 51

Publication number: FPA 14-01

Author(s): Mariko Langness, Phillip Dionne, Erin Dilworth, and Dayv Lowry

Abstract

Marine spatial planning (MSP) involves the identification and mapping of marine resources in pursuit of developing long-term utilization plans for these resources after weighing costs and benefits to diverse stakeholders. As part of a coast-wide MSP process funded by the Washington State Legislature the Washington Department of Fish and Wildlife (WDFW), in collaboration with Makah, Quileute, Hoh and Quinault tribes, conducted a 12 month survey in an effort to document the presence of eggs deposited by forage fishes spawning in the intertidal. From October 2012 through September 2013, beaches along the Washington outer coast were surveyed for surf smelt Hypomesus pretiosus, night smelt Spirinchus starksi, and sand lance Ammodytes hexapterus spawn. The specific goals of the study were to: 1) subsample the breadth of the outer coast monthly; 2) identify any forage fish eggs found to the lowest taxonomic level possible; and 3) geo-reference all survey data to provide an easily accessible overview of sampling effort and egg detections to date. A comprehensive sampling strategy for the entire outer coast was designed, with 1003 sampling sites allocated over the 12 month survey. Of the 1003 total planned sites, 835 (83%) were sampled. Smelt eggs were present at 41 of these sites, while the remaining 794 sites were absent of forage fish eggs of any species. Of the sites where smelt spawn was present plus one non-random site, 32 met the WDFW 2+ egg standard and 28 became newly documented spawning sites. Spawn was documented in each month from February through September, one month earlier than suggested by previous sampling efforts. The number of documented spawning sites and number of eggs per site peaked in June and July suggesting a seasonal trend in spawn abundance. Spawning sites were documented in the northern central coast, ranging as far south as site 335 (south of Wreck Creek) and as far north as site 624 (near Ellen Creek). Analysis of the developmental stage of some eggs collected indicated the presence of multiple broods at the same site simultaneously. The presence of eggs at different sites during the late winter and the presence of multiple egg stages at one site suggest that several spawning events occurred during the season. We expect that further sampling would identify a broader spatial and temporal range of smelt spawning on the outer coast. Sampling over multiple seasons would likely increase egg detections as some sites may have only limited use on a seasonal or annual basis.