Sm. Stephens et al., CORTICOSTEROID AND THYROID RESPONSES OF LARVAL AND JUVENILE TURBOT EXPOSED TO THE WATER-SOLUBLE FRACTION OF CRUDE-OIL, Journal of Fish Biology, 50(5), 1997, pp. 953-964
Turbot larvae (24-590 degree C days; 2-32 days post-hatch) and juvenil
es (1345 degree C days; 98 days post-hatch), were exposed for 6 h to 2
5, 33 and 50% water-soluble fraction (WSF) of crude oil in either stat
ic or flow-through test systems. Larvae showed generalized primary end
ocrine responses, identified by elevated whole body cortisol content f
rom as early as 2 days post-hatch. In older larvae and juveniles, the
response was related to the WSF concentration. This dose-response rela
tionship was not apparent in younger and yolk-sac larvae. Whole body t
hyroxine content of turbot larvae exposed to the WSF of crude oil was
increased, but triiodothyronine content remained stable. Aromatic hydr
ocarbon concentrations [benzene, toluene, ethylbenzene and xylene (BTE
X) and naphthalenes] remained constant during flow-through tests, but
65% of the initial level of BTEX hydrocarbons and 40% of the naphthale
nes were lost during static exposures. Larval mortalities increased wi
th exposure to an increasing concentration of crude oil WSF. Larval ac
tivity was significantly reduced even at the lowest WSF concentration.
(C) 1997 The Fisheries Society of the British Isles.