Shoot first, and then ask questions: A look at aquarium fish imports and invasiveness in New Zealand

Abstract

A risk analysis is being undertaken of threats to natural ecosystems in New Zealand from importation of aquarium fish. The literature on invasiveness reveals global concern about risks from introduced species, though the ecological bases for understanding risk potential seem imprecise and often conflicting. Moreover, whereas some principles espoused may allow identification of species that are high or low risk, these extremes form a continuum wherein the likelihood of establishment cannot be quantified. The likelihood that species, which establish, become seriously invasive is also not quantifiable.

Quantifying invasion pathways: fish introductions from the aquarium trade

“…However, other introductory pathways, including aquarium release, escape from aquaculture facilities, the live food market, intentional introduction, and live bait release (Mills et al 1992), need to also be considered. Intentional release from the aquarium trade is an important pathway for the spread of NIS (McDowall 2004), with species from the aquarium and ornamental trade being responsible for onethird of the world's aquatic NIS (Padilla and Williams 2004). Moreover, there is little regulation of the aquarium trade in terms of restricting potentially nuisance NIS (Ricciardi and Rasmussen 1998;McDowall 2004;Rixon et al 2005).…”

Molecular genetic tools for environmental monitoring of New Zealand's aquatic habitats, past, present and the future

“…The introduction of new species into freshwater habitats has had detrimental effects on physical properties such as water quality and adversely affected other species (e.g. native freshwater fish; McDowall 1990), as well as introducing pathogens and parasites to new areas (McDowall 2000(McDowall , 2004Townsend 2003). New Zealand is no exception, with approximately 21 species of introduced fish present in freshwaters (McDowall et al 2000), many of which have resulted in a suite of adverse effects.…”

“…Currently, 1010 species of freshwater fish are permitted to be imported into New Zealand under the 2011 Import Health Standard for Ornamental Fish and Marine Invertebrates from All Countries. However, the identification of fish, especially larval fish, can be difficult because of the lack of identifying morphological features, and there is evidence that unapproved species have been imported into New Zealand in the past (McDowall 2004). Molecular tools can improve biosecurity by ensuring the accurate identification of imported fish.…”

Invasive Predators: a synthesis of the past, present, and future

“…A more recent threat is transporting and releasing fish through the pet trade (McNeely and Schutyser 2003). Aquarium fish represent a huge reservoir of potential invasive species with more than 5000 fish species traded globally and little is known of their potential effects (McDowall 2004). In the United States, up to 65% of the established nonnative fish populations species likely originated from the aquarium fish trade (Courtenay and Stauffer 1990).…”

“…However, there are problems with this approach as well. Many of the species listed on white lists are actually genera in New Zealand, thus one genera listed could contain more than 800 species with many species having unknown effects (McDowall 2004). Further, government agents must be able to accurately identify the species, hybrid, or subspecies in all stages development to effectively restrict or allow importation.…”