Changes to the histological gill structure and haemolymph composition of early blue swimmer crab Portunus pelagicus juveniles during elevated ammonia‐N exposure and the post‐exposure recovery |
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| Authors: | Nicholas Romano Chaoshu Zeng |
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| Institution: | School of Marine and Tropical Biology, James Cook University, ?Townsville, Qld, Australia |
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| Abstract: | It is yet unclear whether sub‐lethal ammonia‐N levels cause irreparable damage to aquatic crustaceans, or if recovery is possible, the potential factors involved. The aim was to investigate the effect of 0.706 and 2.798 mmol L?1 ammonia‐N exposure on the haemolymph osmolality, Na+, K+, Ca2+, pH, ammonia‐N, total haemocyte counts (THC) and gill histopathology of Portunus pelagicus juveniles at 0, 3, 6, 12, 24 and 48 h respectively. Following 48 h, crabs were transferred to pristine seawater allowing a recovery period up to 96 h and similarly measured. In addition moribund crabs, induced from lethal ammonia‐N levels of 7.036 and 10.518 mmol L?1, were measured for haemolymph osmolality/ions and pH levels. The results demonstrate that despite severe gill damage within 6‐ and 1 h of 0.706 and 2.798 mmol L?1 ammonia‐N exposure, respectively, no significant change (P>0.05) in the haemolymph osmolality, Na+, K+, Ca2+ or pH levels occurred or by ammonia‐N‐induced morbidity. Although the gills can completely recover within 24 and 48 h post exposure to 0.706 and 2.798 mmol L?1 ammonia‐N, respectively, likely facilitated by significant haemocyte increases (P<0.05) within the haemolymph and gill lamellae, dependent factors were the previous ammonia‐N concentration and recovery duration while individual variability was also noticed. |
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| Keywords: | gill histology haemolymph ammonia osmoregulation Portunus pelagicus recovery sub‐lethal ammonia‐N THC |
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