New Zealand Journal of Marine and Freshwater Research abstracts
Responses of seven species of native freshwater fish and a shrimp to low levels
of dissolved oxygen
TRACIE L. DEAN*
JODY RICHARDSON
National Institute of Water & Atmospheric
Research Ltd
P. O. Box 11 115
Hamilton, New Zealand
*Present address: Department of Conservation, Private Bag 3072,
Hamilton, New Zealand.
Abstract The tolerances of seven New Zealand freshwater fish
species and one species of shrimp to low levels of dissolved oxygen were
determined in the laboratory by holding fish at dissolved oxygen levels of 1,
3, or 5 mg litre-1 for 48 h at 15deg.C. Juvenile rainbow trout
(Oncorhynchus mykiss) were also tested for comparison. All of the banded
kokopu whitebait (Galaxias fasciatus), juvenile torrentfish
(Cheimarrichthys fosteri), adult and juvenile common smelt
(Retropinna retropinna), juvenile common bully (Gobiomorphus
cotidianus), and trout were dead after 48 h exposure to 1 mg
litre-1. Adult and juvenile inanga (Galaxias maculatus),
adult common bully (Gobiomorphus cotidianus), and shrimp (Paratya
curvirostris) had mortalities ranging from 27 to 80% at 1 mg
litre-1, whereas all of the elvers (Anguilla spp.) survived.
Juvenile rainbow trout were the most sensitive of the species tested, and the
only species that had mortalities during exposure to 3 mg litre-1.
No deaths of any fish occurred at 5 mg litre-1. Time to 50%
mortality at 1 mg litre-1 for common smelt (adult and juvenile) and
juvenile common bully were similar to those for juvenile rainbow trout. Most
fish moved towards the surface within the first few hours of exposure to 1 mg
litre-1. Rainbow trout was the only species that showed consistent
surfacing behaviour at 3 mg litre-1 and rarely were fish observed to
move towards the surface at 5 mg litre-1. Within the limits
of the lifestages and species tested, adequate protection is provided for
native fish by adopting the United States Environmental Protection Agency
dissolved oxygen criteria for salmonid waters.
Keywords dissolved oxygen; tolerance; behaviour; fish;
Anguilla dieffenbachii; Anguilla australis; Cheimarrichthys
fosteri; Galaxias fasciatus; Galaxias maculatus;
Gobiomorphus cotidianus; Oncorhynchus mykiss; Retropinna
retropinna; Paratya curvirostris
M98036
Received 1 July 1998; accepted 12 November 1998
PDF file of entire paper: medium quality (639K); (scanned from paper original: notes about this process)
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