Aquaculture as a vector for marine invasions in California

Abstract

Although ballast water and hull fouling are widely recognized as important vectors for marine invasions, the risk posed by commercial aquaculture remains poorly quantified. To understand the importance of aquaculture as an invasion vector in California, we conducted an analysis of both current and historical introductions of marine and estuarine species associated with aquaculture using a comprehensive database ('NEMESIS') and permitting records for species imported into California. Our results showed that 126 non-native species associated with commercial aquaculture have been reported from California waters and 106 of these have become established. The vast majority are unintentional introductions linked to historical importation practices of the aquaculture industry. To understand the consequences of these invasions, we reviewed the literature on the impacts of mollusk and algal species introduced into California via aquaculture. Of the few studies we found, the majority demonstrated negative impacts on native species. Finally and significantly, we found that changes in aquaculture importation practices over the past decade have resulted in most shellfish currently being imported as larvae or juveniles. Consequently, rates of unintentional introductions have been reduced. We cautiously conclude that current aquaculture importation in California represents a minor risk as a vector for introductions of NIS.

Biotic exchange from movement of ‘static’ maritime structures

“…Davidson et al 2008a;Yeo et al 2010; Table 2). Aquaculture production had a long history as a primary vector of NIS introduction (Naylor et al 2001), although changing industry practice and regulation have subsequently reduced its vector potential (Grosholz et al 2015). Aquaculture infrastructure and gear are second only to floating docks in recorded incidence of nonindigenous tunicate biofouling (Simkanin et al 2012).…”

Going beyond the search for solutions: understanding trade-offs in European integrated multi-trophic aquaculture development

“…The provision of feed is the single largest contributor to resource use and emissions from opencage salmon production (Grosholz et al 2015). If instead of framing productivity in terms of per unit feed, we frame it in terms of per unit of fish meal or fish oil from wild fish stocks (biotic depletion), then the recycling of nitrogen lost to the environment back into marine proteins and lipids, and the subsequent reincorporation into fish feed, offers opportunities to increase the productivity in a way that may be meaningful to the farmer.…”

Introduction of non-native marine fish species to the Canary Islands waters through oil platforms as vectors

“…In the case of anthropological factors, the new distribution areas are linked to the transport vector of nonnative fish species. In this sense, some vectors of introduction of nonnative fish species have been described including, among others, ballast water transport (Carlton and Geller, 1993;Wonham et al, 2000), marine aquaculture (Liao et al, 2010;Grosholz et al, 2015), aquarium trade (Semmens et al, 2004), oil platforms (Foster and Willan, 1979;Friedlander et al, 2014), and movements through channels (Carlton, 1989;Mavruk and Avsar, 2008). Introduction and spread of nonnative species are considered one of the main threats to biodiversity in the marine context (Molnar et al, 2008) and, in recent years, the level of interest in introduced species has increased worldwide (Lockett and Gomon, 2001;Molnar et al, 2008).…”