Discrimination of New Zealand stream waters by glass eels of Anguilla australis and Anguilla dieffenbachii

Abstract

This study tested the hypotheses, using glass eels of longfin eels Anguilla dieffenbachii and shortfin eels Anguilla australis migrating into fresh waters, (1) that both species prefer water from their river of collection to well water, (2) that shortfin eels prefer lowland, pastoral stream water to mainstem river water, (3) that longfin eels are attracted to both waters but do not prefer one to the other, and (4) both prefer water scented with geosmin, a widely occurring metabolite of bacteria and algae, to well water. Glass eels of both species from a river on the west coast of South Island, New Zealand, and shortfin glass eels from an east coast river significantly preferred water from their river of capture to well water. Two to three times as many eels chose their own river water as chose well water. Longfin eels were rare in the east coast river. Shortfin glass eels from the two rivers chose lowland stream water to mainstem river water about two to one in three experiments with different pairs of waters to which they had no prior exposure. Longfin glass eels significantly chose mainstem river water over lowland water in one pair but showed no preference when presented with a different pair. Reactions to solutions of geosmin at concentrations of 10 5 -10 7 mg l 1 were inconclusive, with geosmin being preferred significantly, by shortfin eels, in only one experiment. The interspecific differences in discrimination of natural waters demonstrated in this study, with shortfin eels preferring lowland waters and longfin eels more indifferent to water types, are in broad agreement with both the distribution of adults and observations on their habitat preferences.

Anguilla rostrata glass eel ingress into two, U.S. east coast estuaries: patterns, processes and implications for adult abundance

“…For example, the ability of A. anguilla glass eels to detect terrestrial chemical cues increases significantly with more fresh water (Sola & Tongiorgi, 1996). Other studies have found that glass eels preferentially orient towards water treated with bacteria and algae (McCleave & Jellyman, 2002). Discharge-related plumes carrying chemical signatures available to glass eels may extend for many kilometres outside of an estuary with a residence time of weeks.…”

Population size, growth and movements of Anguilla australis in a small lake

“…The habitat preferences of A. australis and A. dieffenbachii differ (Jellyman et al, ) and lowland lakes like the one in this study, are invariably dominated by A. australis (McDowall, ; Jellyman et al, ). It is likely that the olfactory choices that glass eels of both species make about entry into specific waterways (McCleave & Jellyman, ) persist through the upstream migration phase and result in interspecific differences in habitat selection. Although recruitment into the Groynes Lake was not observed, fishes < 120 mm L T of both species are adept at climbing vertical surfaces (Jellyman, ) and would readily negotiate the outlet weir.…”

Increased abundance of European eel (Anguilla anguilla) in acidified Norwegian rivers after liming

“…This well-developed sense of smell is strengthened by the fact that elvers exhibited a stronger positive rheotaxis to fresh water than to salt water (Miles 1968). However, there may exist intrastreams variation in attraction of elvers (Miles 1968;McCleave & Jellyman 2002), and salinity and temperature may be more important than odour in determining orientation in glass eel (Tosi et al 1990).…”