Small but tough: What can ecophysiology of croaking gourami Trichopsis vittata (Cuvier, 1831) tell us about invasiveness of non-native fishes in Florida?

Pamela J Schofield,Jessica M Schulte

doi:10.3897/neobiota.28.5259

Abstract

Trichopsis vittata (Cuvier, 1831) is a small, freshwater gourami (Fam: Osphronemidae) native to southeast Asia. It was first detected in Florida in the 1970s and seems to have persisted for decades in a small area. In this study, we documented T. vittata’s ecophysiological tolerances (salinity and low-temperature) and qualitatively compared them to published values for other sympatric non-native species that have successfully invaded much of the Florida peninsula. Trichopsis vittata survived acute salinity shifts to 16 psu and was able to survive up to 20 psu when salinity was raised more slowly (5 psu per week). In a cold-tolerance experiment, temperature was lowered from 24 °C at 1 °C hr -1 until fish died. Mean temperature at death (i.e., lower lethal limit) was 7.2 °C. Trichopsis vittata seems as tolerant or more tolerant than many other sympatric non-native fishes for the variables we examined. However, T. vittata is the only species that has not dispersed since its introduction. Species other than T. vittata have broadly invaded ranges, many of which include the entire lower third of the Florida peninsula. It is possible that tolerance to environmental parameters serves as a filter for establishment, wherein candidate species must possess the ability to survive abiotic extremes as a first step. However, a species’ ability to expand its geographic range may ultimately rely on a secondary set of criteria including biotic interactions and life-history variables.

Highlights

Destructive ecological impacts have been attributed to the introduction and establishment of non-native fishes across the globe (Canonico et al 2005; Pelicice and Agostinho 2009; Vitule et al 2009)
Understanding the characteristics associated with invasiveness is especially important in predicting potential establishment and spread of newly introduced species or those considered a threat for introduction
Trichopsis vittata used in the cold-tolerance study averaged 0.73 g (+ 0.67 standard deviation [SD]; range 0.20–3.00 g; n = 25), and 3.7 cm TL (+ 0.99 SD; range 2.5–5.9 cm)

Summary

Introduction

Destructive (sometimes catastrophic) ecological impacts have been attributed to the introduction and establishment of non-native fishes across the globe (Canonico et al 2005; Pelicice and Agostinho 2009; Vitule et al 2009). Variation in the ability of species to establish and spread (i.e., ‘invasiveness’ sensu Rejmánek et al 2002) has provided clues to underlying ecological attributes correlated with invasiveness (García-Berthou 2007). Understanding the characteristics associated with invasiveness is especially important in predicting potential establishment and spread of newly introduced species or those considered a threat for introduction. Less abundant are data on species that were introduced and died out over time, or those that were introduced and established but did not become invasive. Data on those non-invasive species can be difficult to obtain when species were not intentionally introduced (e.g., via stocking). The fate of these populations is important as they may provide clues to allow researchers to be able to identify characteristics unique to invasive fishes from those shared between invasive and non-invasive species

Methods

Results

Conclusion