Native Freshwater Species Research Articles

Development of whole-sediment toxicity identification and evaluation (TIE) techniques for two Australian freshwater species: Chironomus tepperi and Austrochiltonia subtenuis.

Most of the public literature and available guidance documents on the conduct of freshwater whole-sediment toxicity identification and evaluations (TIEs) detail the use of test organisms and amending agents that are readily available in North America. These commonly used test organisms and the supported amending agents, however, are not available and largely inappropriate (i.e., not native species) for conducting whole-sediment TIEs outside of North America. The overall objective of the present study was to build foundational methods for performing freshwater whole-sediment TIEs in Australia. We examined the capability of 3 amending agents: ANZ38 Zeolite (for ammonia; Castle Mountain Zeolites), Oxpure 325B-9 Activated Carbon (for nonpolar organics; Oxbow Activated Carbon), and Lewatit MonoPlus TP 207 (for cationic metals; Lanxess Deutschland) on 2 Australian native freshwater species: the midge Chironomus tepperi and the amphipod Austrochiltonia subtenuis. To evaluate the effectiveness of each amendment, bioassays were conducted with spiked sediments of ammonia, permethrin (as part of a commercial formulation), and copper using acute median lethal concentrations (LC50s) for both species and growth median effect concentration (EC50) of midges as the endpoints of interest. Environ Toxicol Chem 2017;36:2476-2484. © 2017 SETAC.

Engineered water level management facilitates recruitment of non-native common carp, Cyprinus carpio, in a regulated lowland river

River regulation can advantage non-native aquatic biota at the expense of native species. Nevertheless, flow regulating structures are sometimes used with the aim of achieving positive environmental outcomes in aquatic ecosystems. In the lower River Murray, Australia, drought-induced water level recession and acid sulfate soil exposure prompted the construction of an earthen levee, isolating a section of river channel (the Goolwa weir pool (GWP)) within which water levels were managed to mitigate a risk of water body acidification. The present study aimed to determine the impact of water level management on the fish community by investigating variation in species abundance and recruitment between sites subject to water level management in the GWP and unmanaged sites in Lake Alexandrina. Prior to levee construction, in August 2009, the abundance of the non-native common carp was similar in the GWP and Lake Alexandrina. Following water level management, in December 2009 and April 2010, the abundance of common carp in the GWP was approximately 1000 and 250 times greater than abundance in Lake Alexandrina, as a result of recruitment of young-of-year fish. No native freshwater species were significantly more abundant in the GWP in August 2009, December 2009 or April 2010. The results of this study suggest that the isolation of a river reach and a managed rise in water level facilitated spawning and recruitment of a non-native fish species. As such, the ecological benefits and risks of restoration and mitigation projects that involve the construction of flow regulating structures and water level management should be carefully considered.

Invaders are not a random selection of species

We assembled information on 119 species of freshwater macroinvertebrate invaders in North America and Europe, and compared them to all native freshwater species in North America and Europe. We tested whether the invaders were a random or selected group among taxa (phylum or class), water quality requirements, and feeding habit. We found that freshwater macroinvertebrate invaders are not a random selection of species, and are over-represented by molluscs and crustaceans, while taxa richness of native communities are dominated by insects. Over 35% of native species of aquatic invertebrates in North America are only able to live in areas with excellent or very good water quality, and are intolerant of organic pollution. In contrast, all invaders are tolerant of at least moderate amounts of organic pollution. There was a significant difference in the distribution of feeding habits between native species and invaders: collector-filterers (including suspension feeders) were 2.5-3 times more abundant, and predators were 3-4 times less abundant among invaders than among native invertebrates. The ongoing spread of exotic species affects the biodiversity of selected taxa, shifts communities toward greater tolerance of organic pollution and increases the numbers of suspension feeders, thereby enhancing benthic pelagic coupling in waterbodies with high densities of invaders. Because these processes are very similar in Europe and North America, we suggest that the observed patterns may have a common global effect.

Importance of reservoirs for the conservation of freshwater molluscs in a tropical urban landscape

Freshwater species and ecosystems are gravely imperiled, particularly within urban landscapes of tropical Asia. In one of the region’s most urbanized landscapes (i.e., Singapore), we determined: (1) the importance of six different habitats (i.e., catchment reservoirs, estuarine reservoirs, forest streams, rural streams, ponds and monsoon canals) for conserving the diversity of freshwater molluscs; (2) key environmental factors (e.g., pH) affecting molluscan distribution; (3) important biogeographical determinants (e.g., area) of molluscan richness within each habitat; and (4) the habitat affinities of introduced species. High sampling saturation was achieved at most study habitats with minimal sampling effort, suggesting that the utilization of molluscs as bioindicators can expedite freshwater conservation initiatives. Estuarine reservoirs (6.0 ± 2.0) had the highest molluscan richness, vis-à-vis catchment reservoirs, forest streams, rural streams, ponds and monsoon canals (3.0 ± 1.5; 0; 3.3 ± 2.0; 1.8 ± 0.5 and 3.5 ± 0.5 respectively). Both reservoir types possessed species compositions distinct from other habitats and contained majority (76%) of the sampled species. Reservoirs therefore serve to conserve the bulk of local freshwater malacofauna, especially if they are maintained at near-neutral pH levels (i.e., ∼7.3) and contain large substrates (i.e., rocks). Area was the best predictor of molluscan richness across all habitats, implying that larger freshwater habitats require higher conservation priorities than smaller ones. Introduced (non-native) species (e.g., Pomacea canaliculata) had high affinities for reservoirs, which are in need of monitoring to curb population expansions. The interminable growth of human settlements urgently requires a reconciliatory approach, which includes the ecologically-sound design and management of modified habitats to complement reserves in sustaining native freshwater species.

Fish fauna in inland waters of the Pilbara (Indian Ocean) Drainage Division of Western Australia evidence for three subprovinces

This paper describes the distribution of fishes in inland waters of the Pilbara (Indian Ocean) Drainage Division of Western Australia. 48 842 fish representing 29 species (including one undescribed plotosid catfish) were recorded from 148 of the 171 sites sampled in 21 river systems throughout the Pilbara Drainage Division, i.e. from the Irwin River in the south to the DeGrey River in the north. Of these, 26 844 were from 13 native freshwater species (this total includes the catadromous Indian short-finned eel Anguilla bicolor McClelland 1844 and an undescribed plotosid catfish), 3 099 were from 12 marine/estuarine species and a further 18 899 were from four introduced species. In addition, the Pilbara Drainage Division contains two endemic cave fishes in the North West Cape (Humphreys & Adams 1991; Allen et al. 2002). The results of this study suggest that the Pilbara Drainage Division can be divided into three subprovinces, one for the westwards flowing rivers, i.e. from the Greenough to Lyndon (Southern Pilbara Subprovince), another for the northwards flowing rivers, i.e. from the Yannarie to the DeGrey (Northern Pilbara Subprovince), and a third for the subterranean waters of North West Cape (North West Cape Subprovince).

Interannual variation of fish assemblage structure in a Mediterranean river: implications of streamflow on the dominance of native or exotic species

AbstractStreams in mediterranean‐type climate regions are shaped by predictable seasonal events of flooding and drying over an annual cycle, but also present a strong interannual flow variation.The Guadiana River is one of the most important rivers in the Iberian Peninsula. The fish fauna presents 11 native freshwater species, including eight with high conservation status. Several exotic species are present, the most important being the American centrarchids pumpkinseed fish and largemouth bass. As a typical mediterranean‐type river, the Guadiana has an irregular hydrological regime with severe drought periods and floods; the interannual variation of discharge presents a ratio of c. 100 to 1.From 1980 to 1995 several dry years were observed, culminating in the drought of 19910/92–19947/95. Analysing the variation of the fish assemblage structure during this period, exotic species (mostly pumpkinseed) progressively increased, strongly dominating in 1995. Indigenous populations dramatically decreased and a previously common endemic cyprinid (Anaecypris hispanica Steindachner) became endangered and one of the most threatened fishes of Europe. However, the following years presented above‐average flows with several flood events and an inverse process occurred, with native species increasing their contribution in a short period.The importance of floods as a disturbance factor in the control of lentic or slow flowing water exotics is discussed. Native species apparently possess adaptive responses to high flows which exotics lack. This hypothesis is consistent with probability‐of‐use curves and preflood–postflood surveys. Results emphasize the importance of floods in the environmental flows of mediterranean‐type rivers. In the absence of flooding disturbance, exotic fish populations predictably grow, increasing the pressure on native species; abiotic disturbance may supersede deterministic outcomes of predation or competition and influence community structure by reducing populations of the exotic species. Copyright © 2003 John Wiley & Sons, Ltd.

Marine nutrient contributions to freshwater apex predators.

Recent investigations into the nutrient cycling of coastal ecosystems have suggested that migratory or anadromous fish could be important vectors of marine nutrients. Anadromous fish have assimilated marine nutrients that would contribute to the nutrient budgets of freshwater systems by excretion, gamete release, or the decay of post-reproductive carcasses. However, the extent to which freshwater predators utilize marine material is not well understood. In systems where anadromous fish temporarily constitute a major portion of the fish community, they may contribute substantially to the diet of piscivorous fish and other predators. Here we show the contribution of anadromous blueback herring, shad, and alewife (Alosa) to diets of large, non-indigenous piscivorous catfish (Ictalurus furcatus) using δ34S and δ13C. The spawning anadromous Alosa, captured in tidal freshwater, had enriched δ34S and δ13C values compared to resident, native freshwater species. As a result of consuming the anadromous Alosa, the I. furcatus isotope signature shifted towards the marine signal. The isotope analysis revealed that anadromous fish contribute substantially to the diet of most captured I. furcatus. The percentage of anadromous Alosa carbon and sulfur that was incorporated into I. furcatus (≥38 cm total length) ranged from 0 to 84% and 10 to 69%, and had means (±SD) of 42 (±24) and 43 (±16)%, respectively. Although the δ15N signal of marine-derived biomass is enriched by approximately 3‰ relative to terrestrial or freshwater biomass, it was not as useful as δ34S and δ13C for nutrient source owing to trophic fractionation. This study demonstrates that anadromous fish may be a significant source of nutrients to tidal freshwater apex predators.

The application of biogeographical zonation and biodiversity assessment to the conservation of freshwater habitats in Great Britain

1. Twelve biogeographical zones for freshwater habitats in Great Britain were derived, using detrended canonical correspondence analysis of data on climate, relief, geology, soils and land use, in conjunction with occurrence data for more than 300 native freshwater species. 2. The taxonomic groups used were aquatic macrophytes, dragonflies, freshwater molluscs, amphibians and selected leeches, water beetles and crustaceans. The computer database of the Institute of Terrestrial Ecology's Biological Records Centre was used as the principal source of species data. 3. Within each of the 12 biogeographical zones, 10×10 km square ‘hotspots’ for species richness and rarity were identified. 4. The significance of this work for the conservation of freshwater habitats and species in Great Britain is discussed. Copyright © 1999 John Wiley & Sons, Ltd.

Avoidance of suspended sediment by the juvenile migratory stage of six New Zealand native fish species

The avoidance response of the migratory juvenile stage of six species of diadromous fish to different levels of suspended solid (SS) was determined in the laboratory using a two‐choice avoidance tank. Trials were mostly conducted with resuspended sediment from the outlet of Lake Waahi, New Zealand, but a series of tests was also conducted with kaolin for comparison. Banded kokopu (Galaxias fasciatus) was the most sensitive species, displaying a 50% avoidance response to kaolin and Waahi silt at 17 and 25 NTU, respectively. Koaro (Galaxias brevipinnis) and inanga (Galaxias maculatus) were found to be less sensitive than banded kokopu, with a 50% avoidance response to Waahi silt at 70 and 420 NTU, respectively. Shortfinned and longfinned elvers (Anguilla australis and/1, dieffenbachii), and redfinned bullies (Gobiomorphus huttoni) showed no avoidance behaviour, even at the highest turbidities (1100 NTU) tested. Based on these laboratory results, and until field testing is undertaken, a limit of about 15 NTU in otherwise clear waterways should ensure that the upstream migration of some of the most common New Zealand native freshwater species will not be affected.

Comparison of fatty acid composition of muscle, liver, mature oocytes, and diets of wild and captive Macquarie perch, Macquaria australasica, broodfish

Macquarie perch, an Australian native freshwater species, does not respond to hypophysation when caught from the wild, spawned and subsequently held in captivity. In this paper, the fatty acid composition of the liver, mature oocytes, muscle and diets of wild and tank-reared fish are compared. The fatty acid profiles of the two groups of fish were closely related to their diets, and of the fatty acid profiles, those of the liver showed the least variation between years. The most significant differences in the fatty acid profiles of the two groups were observed in the liver, in which tank-reared fish had more monoenes, largely 16:1 n − 7, but less n − 6 fatty acids and a higher n − 3 to n − 6 ratio than did wild fish. Muscle differed from other tissues in that 16:0 and 16:1 n − 7 acids were present in greater amounts than 22:6 n − 3 and did not show a consistent variation between wild and tank-reared fish. In the mature oocytes of wild fish polyunsaturated fatty acids were present in consistent amounts between years. The mature oocytes of tank-reared fish had lower levels of n − 6 fatty acids and as a result these oocytes had significantly higher n − 3 to n − 6 ratios compared with those of wild fish. Principal component analysis indicated that the fatty acid composition of all three tissues was clearly separable in the two groups of fish. It is hypothesised that the low levels of n − 6 fatty acids, in particular 20:4 n − 6, in the diet of tank-reared Macquarie perch, may be responsible for the lack of response to hypophysation techniques in these fish, owing to the lack of precursors for the synthesis of prostaglandins. It is also suggested that Macquarie perch, like its marine relatives, is incapable of de novo synthesis of the highly unsaturated fatty acids of the n − 3 and n − 6 series and has to rely on its diet for these fatty acids.