Effect of Transport Method on Subsequent Survivorship and Gonad Yield/Quality in the Red Sea Urchin Mesocentrotus franciscanus

Abstract

Sea urchin gonad enhancement entails collecting adults with low gonad yields from the wild, placing them in land-based or sea-based captivity, and feeding them a prepared or natural diet to produce high quality/quantity gonads for marketing. Collection and transportation to the culture facility can be stressful to the urchins and cause subsequent mortalities and suboptimal gonad yield/quality. Minimizing this handling stress is critical to ensuring maximum survivorship and optimal gonad enhancement, yet very little research has examined this, with no information being available for the red sea urchin Mesocentrotus franciscanus. The present study examined survivorship, gonad yield, and gonad quality of red sea urchins 2 weeks after exposure to three 2-h transport methods: (1) milk crates placed in two plastic fish totes filled with ambient seawater ("wet crate"), (2) sealed Styrofoam boxes filled with ambient seawater ("wet box"), and (3) sealed Styrofoam boxes without seawater, but with wet burlap placed on top of the urchins ("dry box"). While no gonadal parameters significantly differed between transportation methods, the percentage of survivorship for both the wet boxes and wet crates was 100%, while that for the dry boxes was 58.3% after 2 weeks, indicating that wet transport should be preferred over dry transport for red sea urchins.

Formulated feeds prolong the reproductive period of a cultured echinoid

“…There are few published studies on sea urchin roe enhancement occurring in sea‐based cages (but see Mooney and Bunnell 2001; Cárcamo 2004; Hagen and Siikavuopio 2010; James et al 2017b; Takagi et al 2017), and only one (James et al 2017b) mentions sea urchin survivorship. Many sea urchin studies have shown that most mortalities occur in the first 2 weeks posttransport and then drop to little or none by the end of the experiment (Minor and Scheibling 1997; Siikavuopio et al 2004a, 2004b; Dale et al 2005; James and Evensen 2018; Warren and Pearce 2020). Our study, however, did not show evidence of a large mortality occurring within the first 2 weeks postcollection but rather minimal mortalities occurring throughout the whole study, still resulting in high survivorship overall (Figure 2).…”

“…Our study, however, did not show evidence of a large mortality occurring within the first 2 weeks postcollection but rather minimal mortalities occurring throughout the whole study, still resulting in high survivorship overall (Figure 2). Mortality of sea urchins that is incurred as a result of collection and transport to aquaculture facilities is a crucial factor for the economic viability of a sea urchin gonad enhancement operation (Valvåg 2003; Dale et al 2005; Warren and Pearce 2020). The present results regarding survivorship show that the collection and transport methods that were used were appropriate and resulted in minimal mortalities of green sea urchin.…”

Live transport of the green sea urchin ( Strongylocentrotus droebachiensis ) in air and immersed in seawater and the impact on subsequent roe enhancement after in‐water transport

“…This involves the collection/harvesting of mature sea urchins from areas where the roe content may be very low or, too poor of quality for commercial processing (these areas are referred to as sea urchin barrens). The harvested sea urchins are then transferred and held in land or sea‐based holding systems for periods between 8–12 weeks and fed formulated feeds to enhance the quantity and quality of the roe (Warren & Pearce, 2020). This creates a valuable, much sought after and lucrative product from a previously valueless resource in a relatively short period of time.…”

“…The conclusions from this study were that rough handling and air exposure had a significant impact on mortality during subsequent roe enhancement of the sea urchins. A study by Warren and Pearce (2020) studied the effects of transport on the roe enhancement of the Pacific red sea urchin Mesocentrotus franciscanus . The study examined survivorship, gonad yield, and gonad quality of red sea urchins 2‐weeks after exposure to 2 hours of either ‘wet’ or ‘dry’ transport methods.…”

“…sea urchin barrens). The harvested sea urchins are then transferred and held in land or sea-based holding systems for periods between 8-12 weeks and fed formulated feeds to enhance the quantity and quality of the roe (Warren & Pearce, 2020). This creates a valuable, much sought after and lucrative product from a previously valueless resource in a relatively short period of time.…”