Transportation of fish, although stressful, is an inevitable procedure in aquaculture practices. In this
study, we investigated the changes in biochemical and haematological indices in advanced fingerlings
of rohu, Labeo rohita in order to optimize the packing density as is imperative to avoid transportation
stress and associated mortality. The fish (14.00–15.00 cm) were packed in sealed double layer oxygen
packed polythene bags of 30 L capacity containing 7.5 L of water and transported for 2 h and 30 min in
a motor vehicle at three packing densities, viz., 67 g L−1, 134 g L−1, and 201 g L−1 and transported from
hatchery to Kolkata, India covering a distance of about 55 km. A cumulative mortality of 30% was recorded
during and after transportation in fish transported at 201 g L−1; while the other two packing densities
recorded no mortalities. Transportation and packing density induced stress affected the functioning of
liver and kidney. The activities of transaminases and lactate dehydrogenase, breakdown of protein and
creatinine phosphate, cortisol induced glucose production were significantly increased in advanced rohu
fingerlings to cope with the energy demand posed by transportation and higher packing density stress.
Low levels of dissolved oxygen and high levels of ammonia-nitrogen were noticed in different packing
densities after transportation. The results suggested thatthe optimum packing density for advanced rohu
fingerlings for 2–3 h duration of transport would be 134 g L−1, which kept the stress at low levels. The
serum alanine aminotransferase levels can serve as a good marker for fish liver health as the increment
was more prominent when subjected to transportation stress.