Top left: Ghost shrimp holes in mudflats Top Right: Ghost shrimp (Neotrypaea californiensis) Bottom left: Research kayak and mapping Bottom Right: Enthusiastic volunteer, Cat Glashier, shows off a Ghost Shrimp

Introduction

The ghost shrimp is a small burrowing shrimp, which is abundant in the intertidal mudflats from Alaska to Baja, California. The Grice Bay ghost shrimp is incredibly important to the migrating Wimbrels who feed on them during their only British Columbia stopover during their long migrations. The ghost shrimps are also the main bioturbators in Grice Bay and there is evidence of bacterial nitrogen fixation associated with the burrowing action of the shrimp making more nitrogen gas available to the marine environment.

Background

In May of 1995, SIMRS started a monthly monitoring program of Grice Bay, when at the time it was a juvenile gray whale (Eschrichtius robustus) feeding ground. During that time it was discovered that the whales were feeding on ghost shrimp and the commensal soft shell clam (Cryptomya californica). In the year 2000 SIMRS mapped major eelgrass meadows in southern Clayoquot Sound including the eelgrass meadow in Grice Bay. While gray whales have not been observed feeding in Grice Bay since 2002, an important aspect of this study was to provide baseline habitat data, which would provide valuable information in the event of a natural or human disruption. This report will compare the habitat data that we have collected.

Habitat Mapping

The Grice Bay habitat mapping done in 1995 (ghost shrimp) and 2001 (eelgrass) (Figure 1) shows that the ghost shrimp habitat measures 3,848,850 m2 in total area and the eelgrass habitat measured 1,626,720 m2 in total area. When the eelgrass habitat was revisited in 2014 it measured 2,151,790 m2 in total area and the ghost shrimp habitat revisited in 2015 measured 4,023,765 m2 in total area (Figure 2). When comparing the change to the eelgrass habitat it appears to have had a large increase over thirteen years (Figure 3A) in 2001 measuring an area of 1,626,720 m2 and in 2014 the area mapped has increased to 2,151,790 m2 in total area. This is a percent increase of 32%. When comparing the change to the ghost shrimp habitat over twenty years (Figure 3B) there is only a slight increase in total area. In 1995 the total area was 3,848,850 m2 area was measured to be 4,023,765 m2, while in 2015 the total. This is an increase of only 4.5%.