Assessing movement of the California sea cucumber Parastichopus californicus in response to organically enriched areas typical of aquaculture sites

Sf Cross,Cm Pearce,P Van Dam-Bates,Dl Curtis,Lle Cowen

doi:10.3354/aei00156

Abstract

An increasing global demand for sea cucumbers has led to interest in benthic ranch- ing of the California sea cucumber Parastichopus californicus beneath existing aquaculture sites in British Columbia, Canada, where high levels of total organic matter (TOM) are typical. The objective of the present study was to investigate movement of P. californicus in relation to areas of increased organic content to assess the feasibility of sea cucumber ranching beneath existing aquaculture sites. A laboratory experiment using adult sea cucumbers showed that P. californicus changed their foraging behaviour based on available amounts of TOM, moving more randomly in high-TOM (~8.0%) areas and more directly in low-TOM (~1.4%) ones. They also moved more rapidly in areas with high TOM than in those with low TOM. As long as animals were exposed to high TOM, they did not abandon random movement. Because of this behaviour, aquaculture tenures may retain a population of cultured individuals, but could also attract wild individuals from the surrounding area.

Highlights

Sea cucumbers have been an important food source for centuries in Asia and have been harvested in China for over 400 yr (Schwerdtner Máñez & Ferse 2010)
Despite growing interest in their culture, and despite significant commercial aquaculture advances that have been made with Apostichopus japonicus and Holothuria scabra (Robinson 2013, Yang et al 2015), there is a general lack of information about the ecology and biology of most species of sea cucumbers of commercial interest (Lovatelli et al 2004). This lack of knowledge extends to the California sea cucumber Parastichopus californicus, a commercially important fisheries species on the west coast of North America including British Columbia (BC)
When presented with high levels of total organic matter (TOM) in the sediment, sea cucumbers displayed more random movement than when TOM levels were low. This type of behaviour would keep an animal in areas with high TOM and bring nearby animals to the same sites, ensuring that new resources are encountered (Pyke 1978, Zimmerman 1979)

Summary

Introduction

Sea cucumbers have been an important food source for centuries in Asia and have been harvested in China for over 400 yr (Schwerdtner Máñez & Ferse 2010). Sea cucumbers may be co-cultured in intertidal ponds. This lack of knowledge extends to the California sea cucumber Parastichopus californicus, a commercially important fisheries species on the west coast of North America including British Columbia (BC), Publisher: Inter-Research · www.int-res.com. Some reports have described suspension feeding either through the mouth (Da Silva et al 1986) or by pumping water through the anus (Jaeckle & Strathmann 2013) This species is suspected to feed continuously while moving nondirectionally (Da Silva et al 1986, Cieciel 2004), while feeding it displays particle selectivity, preferentially ingesting material with high organic content (Ahlgren 1998, Paltzat et al 2008). California sea cucumbers exhibit an escape response to the presence of some sea stars, especially Pycnopodia helianthoides, evidence suggests that only juveniles are vulnerable to predation (Margolin 1976, Cameron & Fankboner 1989)

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