Aquaculture potential of the basket cockle (Clinocardium nuttallii). Part 2: effects of stocking density and depth on second year grow-out performance of three size cohorts in intertidal and off-bottom suspended culture

Abstract

We investigated the effects of culture mode (intertidal and off‐bottom suspended culture) and initial stocking density (5%, 10%, 35% and 70% bottom cover) on survival, growth and condition indices of three size cohorts (16, 22 and 32 mm initial shell length) of the basket cockle, Clinocardium nuttallii, during a second year of grow‐out. In addition, we evaluated the effects of depth (2, 4 and 6 m) in suspended culture. All size cohorts demonstrated significantly higher growth rates, soft‐tissue biomass and condition indices in the off‐bottom suspended system compared to the intertidal one. In suspended culture, however, C. nuttallii exhibited sub‐optimal survival, shell deformities and heavy fouling. For all size cohorts, stocking density had a significant effect on most growth and condition parameters, except meat yield indices, in both culture modes. An initial maximum stocking density of 10% cover is recommended for all size cohorts. Culture depth did not have a consistent statistically significant effect on any of the growth or condition parameters. Depending on the grow‐out scenario, stocking density and harvestable size chosen, the cumulative harvestable proportion after the second year of grow‐out constituted 15.5–63.1% of the seed planted. Our results could be used to develop and improve culture techniques for C. nuttallii and other cockle species.

Population genomics of the basket cockle Clinocardium nuttallii in the southern Salish Sea: Assessing genetic risks of stock enhancement for a culturally important marine bivalve

“…The ultimate success of a C. nuttallii stock enhancement program is a key consideration. Fortunately, hatchery production has been extensively tested in C. nuttallii , and it has long been considered a prime candidate for aquaculture in the region due to ease of culture (Dunham et al, 2013a , 2013b ; Liu, Alabi, & Pearce, 2008a , 2008b ; Liu et al, 2009 , 2010 , 2011 ). Pilot breeding projects by our group have produced large quantities of C. nuttallii seed (>1 M) at relatively low cost and effort (Puget Sound Restoration Fund, unpublished).…”

“…A prime candidate for aquaculture in the region due to ease of culture (Dunham et al, 2013a(Dunham et al, , 2013bLiu, Alabi, & Pearce, 2008a, 2008bLiu et al, 2009Liu et al, , 2010Liu et al, , 2011. Pilot breeding projects by our group have produced large quantities of C. nuttallii seed (>1 M) at relatively low cost and effort (Puget Sound Restoration Fund, unpublished).…”

“…Localized cockle population declines have spurred interest in using aquaculture to supplement beaches with hatchery-spawned and raised juveniles. In fact, C. nuttallii has long been viewed as an attractive species for aquaculture development in the region, and initial research on captive spawning and larval rearing practices in the past decade have proven that C. nuttallii is highly amenable to aquaculture production (Dunham et al, 2013a(Dunham et al, , 2013bLiu, Alabi, & Pearce, 2008a, 2008bLiu et al, 2009Liu et al, , 2010Liu et al, , 2011. However, fishery co-managers in Washington State have agreed that genetic risks associated with aquaculture must be addressed before it can be used as a restoration practice.…”

A rapid, inexpensive, non-lethal method for detecting disseminated neoplasia in a bivalve

“…Basket cockles, a common bivalve native to the PNW, are a long-time traditional food staple for tribal communities (Apeti et al 2013) and popular among recreational harvesters. There is growing interest in basket cockle aquaculture and potentially population enhancement among some Coast Salish tribes and the commercial industry (Dunham et al 2013a, Dunham et al 2013b, though recent observations of DN at a local broodstock source population (R. Elston, personal comm.) limits the viability of these projects.…”