Socioecological factors related to aquaculture introductions and production of Pacific oysters (Crassostrea gigas) worldwide

Abstract

Pacific oysters (Crassostrea gigas) have been introduced worldwide for aquaculture, which can benefit food sovereignty and economic development; however, established non‐native populations may present risks for local organisms and habitats. We reviewed the documented introductions of C. gigas by country to evaluate factors related to introduction, establishment and production, and to determine impacts of feral populations. To date, C. gigas has been introduced in 64 countries and 10 territories, has been established in 32 and contributes to cupped oyster production in 36 (additionally, three native range countries). Oysters were more likely to be introduced and to establish in higher‐latitude countries, but the economic factor of per capita Gross Domestic Product per capita (GDPpc) served as a stronger explanatory variable than latitude for introduction. Earlier introduction and the use for extended periods in aquaculture, not just in trials, further increased establishment. Commercial production increased with coastline length and when established populations were present, but in contrast to establishment, declined at higher latitude. Effects of feral populations have been studied in 11 countries, spanning a range from negative to facilitative as expected for an ecosystem engineer, while reaching levels of concern warranting removal from coastlines in the UK, Norway, Sweden Australia and South Africa. The use of GDPpc in analyses revealed a widespread inequity in terms of low investment in Pacific oyster aquaculture in poorer countries, while richer countries were able to invest not only in aquaculture but also in studies of environmental impacts of feral oysters.

Risk Assessment Model System for Aquatic Animal Introduction Based on Analytic Hierarchy Process (AHP)

“…Crassostrea gigas have strong adaptability and rapid growth performance, and shellfish are easier to manage in quarantine and transportation than fish and crustaceans. During the introduction and cultivation process, strengthening the inspection and control of diseases—as well as strengthening the management of Crassostrea gigas in various fisheries to avoid escape and dispersion during cultivation—can reduce the risk of Crassostrea gigas to a certain extent [ 61 , 62 ]. (4) The risk grade of Trachemys scripta elegans is medium.…”

Restrictions on UK aquaculture of Pacific oyster (Magallana gigas) will not prevent naturalised spread but suppress ecological and economic benefits to coastal communities

“…The non-native origin of M. gigas, their potential impact on coastal ecosystems and their ability to breed in the temperate waters of Northern Europe, have raised several ecological and policy concerns. These centre around their successful dispersal beyond aquaculture sites, their abilities as ecosystem engineers to alter habitats including the transformation of mudflats to oyster reefs, the possible interference with restoration efforts of native O. edulis, competition with other aquaculture species and their settlement on maritime infrastructure (Herbert et al, 2016;Martinez-Garcia et al, 2022). Calls are being made to limit the expansion, or even continuation, of the aquaculture of this species in some areas due to an assumption that current industry activity is the source of free-living dispersing oyster larvae; and that the proposed concerns are being realised.…”

An amplicon panel for high-throughput and low-cost genotyping of Pacific oyster

“…Pacific oyster Crassostrea (Magallana) gigas (Thunberg, 1793;Salvi & Mariottini, 2017), is one of the most valuable aquaculture species globally (Botta et al, 2020). Oyster aquaculture is a significant economic driver and food source for many developed and developing nations (Martínez-García et al, 2022).…”

“…In addition to lower cost per individual, amplicon panels can also be used to genotype non-target variants within an amplicon window, potentially expanding its utility across populations and time, as long as primer sites remain intact and functional. This longevity and malleability may be particularly advantageous to Pacific oysters given their high genetic diversity (Hedgecock et al, 2005;Sauvage et al, 2007), global scale of culture (Boudry et al, 2021;Martínez-García et al, 2022), including genetically diverse large-scale commercial hatcheries (Sutherland et al, 2020), and temporal fluctuations in allele frequencies that occur due to sweepstakes reproductive success (Hedgecock, 1994;Hedgecock & Pudovkin, 2011;Sun & Hedgecock, 2017).…”

“…Pacific oyster Crassostrea ( Magallana ) gigas (Thunberg, 1793; Salvi & Mariottini, 2017), is one of the most valuable aquaculture species globally (Botta et al, 2020). Oyster aquaculture is a significant economic driver and food source for many developed and developing nations (Martínez-García et al, 2022). However, production and growth of the industry outside of China has stagnated due to disease, regulatory issues, and other factors (Botta et al, 2020).…”