Studies on the biology of the New Zealand fresh-water red-finned bully, Gobiomorphus Huttoni (Ogilby), (Eleotridae)

Abstract

The name Gobiomorphus huttoni (Ogilby) replaces Gobiomorphus radiata (C. and V.) for the New Zealand red-finned bully, the latter name being correctly applied to the marine Grahamichthys radiate. The family name Eleotridae (Percomorphi, Gobioidea) is used in place of Gobiomoridae Whitley on grounds of priority. An account is given of general form, disposition of lateral-line pores (found only on the head), the papillae on the head and body, tooth characters, scalation, colouration, colour pattern and colour change. An extended systematic description is also given. The disposition of papillae suggest relationship to the lateral-line system in contrast to their previous description as mucigerous papillae. Characteristics not previously observed for G. huttoni, namely the depressibility of teeth, the presence of pharyngeal teeth and of an air bladder are described. Sexual dimorphism is here described for the first time. The male is larger than the female, has cheek scales, a more bulbous snout, larger vertical fins and a broader, more pointed genital papilla. Further, the body of the male is banded and speckled in orange-red, differing from female colouration which is more sombre. Biological studies were carried out, mostly in the Makara Stream, Wellington. G. huttoni is found inhabiting rapid water in rocky lowland streams and is a predatory carnivore feeding on stream bottom inverterbates, mostly Diptera. Breeding occurs mainly in spring. G. huttoni places the eggs in a crude nest which is guarded by the male. Present indications are that the young are carried to sea, but confirmation of this is needed. Return migration of juveniles takes place from January to March. Other aspects of the biology of G. huttoni investigated include the relationships of the New Zealand species of Gobiomorphus, faunal associates of G. huttoni, predation, competition, habitat requirements, weight-length and condition, and age and growth studies.