Swim
bladder malformation in hatchery-reared striped trumpeter Latris lineata (Latridae)
A.J. Trotter, P.M. Pankhurst,
P.R. Hart –2001
Aquaculture,
198 (1-2): 41-54
Abstract:
Swim
bladder malformation is common in both larvae and later life stages of
cultured striped trumpeter Latris lineata. This study used histology and
gross morphology of whole larvae to describe the progression of abnormal
development that proceeded initial liquid dilation of the primordial swim
bladder. In addition, radiography was used to compare swim bladder
morphology of cultured juveniles with wild-caught specimens. The
histomorphology of the swim bladder prior to lumenal dilation was typical of
transient physostome larvae reported in the literature. A distinct swim
bladder lumen present in larvae between 5.2-5.7 mm standard length (SL) was
assumed to be liquid dilated and coincided with mouth opening. Initial
gaseous inflation was first apparent when larvae attained 5.7-6.2 mm SL,
after the resorption of the yolk sac and oil globule and the onset of first
feeding (<5.5 mm SL). Successful gaseous inflation ranged between 0% and
75% in the cohorts of larvae examined. When gaseous inflation failed to
occur, abnormal development proceeded in which the liquid dilated swim
bladder collapsed, occluding the lumen. Hypertrophy of the swim bladder
epithelium and hyperplasia of the rete mirabile ensued. Radiography revealed
that wild-caught striped trumpeter had a euphysoclist (dual-chambered) swim
bladder, in which the chambers are separated by a diaphragm. In comparison,
cultured juveniles and sub-adults displayed highly varied swim bladder
morphologies, including apparently normal, malformed, and non-functional
swim bladders in which a gaseous lumen was entirely absent. Kyphosis was
inflicted in extreme cases of swim bladder malformation in which a distended
single chamber both displaced the viscera and pushed the spine upwards. It
was concluded that striped trumpeter larvae can be afflicted with swim
bladder malformations consistent with cultured larvae of other transient
physostomes; however, swim bladder malformation of later life stages of
striped trumpeter is atypical in comparison to other literature reports and
may be unrelated to the larval malformation described.
(School
of Aquaculture, Tasmanian Aquaculture and Fisheries Institute and
Cooperative Research Centre for Aquaculture, University of Tasmania, Locked
Bag 1-370, Launceston, Tasmania 7250, Australia, Tel.: +61-3-62-277-234;
fax: +61-3-62-278-035, e-mail: atrotter@utas.edu.au)