Age validation and movement of freshwater eels (<i>Anguilla dieffenbachii</i>and<i>A. australis</i>) in a New Zealand pastoral stream

Chisnall, Benjamin L.; Kalish, John M.

doi:10.1080/00288330.1993.9516573

Cited by 57 publications

(47 citation statements)

References 16 publications

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“…The difference between these studies and ours presumably originated from the small width and high complexity of the Awirs stream, which offered numerous refuges and did not force the eels to move over long distances to find alternative refuges. Chisnall & Kalish (1993), who studied the movements of A. australis and A. dieffenbachii (Gray) by mark recapture also concluded to small scale (< 140 m) movements in a small stream of New Zealand. Similarly, Gunning & Shoop (1962) observed that A. rostrata occupied home ranges of less than 50 m in small Louisiana streams but were using larger ranges in wider streams.…”

Section: Discussionmentioning

confidence: 99%

Seasonal variations in time and space utilization by radio-tagged yellow eels Anguilla anguilla (L.) in a small stream

Baras

Jeandrain

Serouge

et al. 1998

Advances in Invertebrates and Fish Telemetry

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Seven yellow eels (572-643 mm, 318-592 g) Anguilla anguilla (L.) were tagged with surgically implanted radio transmitters (activity circuit, 1.6-1.7 g) and tracked in the Awirs stream, a small (width < 5 m, depth from 0.1 to 1.2 m), densely populated (ca. 250 kg of eel ha −1 ) tributary of the Belgian River Meuse. The eels were positioned daily from late April to mid-August, and their diel activity was studied during twenty four 24-h cycles. During day-time, the eels were resting in rootwads or in crevices inside stone walls or in crevices in between rocks. They became more active in the late afternoon but generally did not leave their residence before sunset, except under overcast weather. Activity peaked during the first part of the night then progressively vanished, and always ended before sunrise. The area exploited during night-time never extended over more than 40 m 2 , except when the eel changed its residence. The intensity and timing of nocturnal activity and the extent of the daily activity area were dependent on water temperature (respectively P < 0.0001, P < 0.05 and P < 0.0005), with eels showing little or no activity when the diurnal temperature did not exceed 13 • C. Eels showed higher agitation under full moon and maintained their activity later in the night (P < 0.05). The eels showed restricted mobility, and occupied small stream areas (from 0.01 to 0.10 ha) in a non sequential mode, except for two fish which were displaced to the River Meuse by a spate in early June and were never recovered. The length and frequency of net daily journeys were higher (P = 0.005) at water temperatures above 16 • C in late May and June, which also corresponded to the period of immigration of eels from the River Meuse. This study thus shows that large yellow eels may adopt a highly sedentary lifestyle in a continental, fast flowing and densely populated environment, even at periods of the year when these stages usually show upstream migrations.

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Section: Discussionmentioning

confidence: 99%

Seasonal variations in time and space utilization by radio-tagged yellow eels Anguilla anguilla (L.) in a small stream

Baras

Jeandrain

Serouge

et al. 1998

Advances in Invertebrates and Fish Telemetry

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“…For example, studies on Anguilla rostrata have found that their yellow eel stage has a restricted home range and that individuals return to their initial habitat after foraging outside their territory (Bozeman et al 1985, Ford & Mercer 1986, Oliveira 1997, or return to their home range after being artificially displaced (Parker 1995). Similarly, studies of New Zealand eels concluded that the large eels have relatively small home ranges and typically only move short distances within these streams (Burnet 1969, Chisnall & Kalish 1993, Jellyman & Sykes 2003. However, within Lake Ellesmere, the constant removal of eels by the commercial fishery means that available habitat is always opening up.…”

Section: Habitat Use and Apparent Movementsmentioning

confidence: 99%

Evidence of different habitat use by New Zealand freshwater eels Anguilla australis and A. dieffenbachii, as revealed by otolith microchemistry

Arai

Kotake²,

Lokman³

et al. 2004

Mar. Ecol. Prog. Ser.

109

112

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The apparent use of marine and freshwater habitats by Anguilla australis and A. dieffenbachii was examined by analyzing the strontium (Sr) and calcium (Ca) concentrations in otoliths of silver eels collected from Lake Ellesmere, which is a shallow brackish-water coastal lagoon in New Zealand. The age and growth of these eels was also examined using their otolith annuli. Size and ages of females were greater than those of males for both species. Growth rates were similar among sex and species, but the highest growth rates were observed in eels that experienced saline environments. Line analyses of Sr:Ca ratios along a life-history transect in each otolith showed peaks (ca. 15 to 21 × 10 -3 in A. australis, 14 to 20 × 10 -3 in A. dieffenbachii) between the core and elver mark, which corresponded to the period of their leptocephalus and early glass eel stage in the ocean. Outside the elver mark, the Sr:Ca ratios indicated that eels had remained in different habitats that included freshwater (average Sr:Ca ratios, 1.8 to 2.4 × 10 -3 ), areas with relatively high salinities (average Sr:Ca ratios, 3.0 to 7.4 × 10 -3 ), and in some cases individuals showed clear evidence of shifts in the salinity of their environments. These shifts either indicated movements between different locations, or changes in the salinity of the lake. There were more individuals of A. australis that used areas with intermediate or high salinities, at least for a short time (85% of individuals), than A. dieffenbachii (30%). These findings suggest that these 2 southern temperate species may have the same behavioral plasticity regarding whether or not to enter freshwater or remain in marine environments, as has been recently documented in several northern temperate anguillid species.KEY WORDS: Anguilla dieffenbachii · Anguilla australis · Age · Growth · Otolith microchemistry · Habitat use · Lake Ellesmere · New ZealandResale or republication not permitted without written consent of the publisher

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“…data). In a mark-recapture study in the pastoral Ahirau Stream (present study), the number of transparent zones following fluorescent labels (tetracycline) on the otoliths of tagged recaptured longfinned and shoitfinned eels corresponded to the number of years these eels were at liberty (Chisnall & Kalish 1993).…”

Section: Age Validationmentioning

confidence: 99%

“…Afterwards, eels are likely to live in specific areas, usually with limited home ranges (Burnet 1969;Jellyman & Todd 1982;Chisnall 1987;Chisnall & Kalish 1993). Growth Percentage of channel length as pool Water temperature is probably the most important factor causing habitat-specific growth differences in longfinned eels.…”

Section: Growth In Different Habitatsmentioning

confidence: 99%

Age and growth of longfinned eels (Anguilla dieffenbachii) in pastoral and forested streams in the Waikato River basin, and in two hydroelectric lakes in the North Island, New Zealand

Chisnall

Hicks

1993

New Zealand Journal of Marine and Freshwater Research

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Growth rates of New Zealand endemic longfinned eels (Anguilla dieffenbachii) from streams in pasture and indigenous forest, and from two hydroelectric lakes (Lakes Karapiro and Matahina), were estimated by otolith examination. Habitat-specific growth was further investigated with measurement of widths of annual bands in otoliths. Longfinned eels 170-1095 mm in length ranged between 4 and 60 years old (N = 252). Eels in pastoral streams grew faster (mean annual length increment ±95% CL = 24 ± 3 mm to 36 ± 7 mm) than eels in streams in indigenous forest (annual length increment 12 ± 2 mm to 15 ± 3 mm). Eels from the hydro-electric lakes had growth rates (annual length increments 19 ± 4 and 19 + 7 mm) similar to eels from pastoral streams. Otoliths of most eels showed annual band widths that indicated growth in several different habitats, corresponding to growth during upstream migration, and limited movement among adult habitats. Estimated age at marketable size (220 g) ranged between 7 and 26 years. The particularly slow growth of longfinned eels in streams in indigenous forest has considerable implications for management. The fast growth rates of eels in hydro-electric lakes provides

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Age validation and movement of freshwater eels (Anguilla dieffenbachiiandA. australis) in a New Zealand pastoral stream

Cited by 57 publications

References 16 publications

Seasonal variations in time and space utilization by radio-tagged yellow eels Anguilla anguilla (L.) in a small stream

Seasonal variations in time and space utilization by radio-tagged yellow eels Anguilla anguilla (L.) in a small stream

Evidence of different habitat use by New Zealand freshwater eels Anguilla australis and A. dieffenbachii, as revealed by otolith microchemistry

Age and growth of longfinned eels (Anguilla dieffenbachii) in pastoral and forested streams in the Waikato River basin, and in two hydroelectric lakes in the North Island, New Zealand

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