Hrvoje Lucić

Stomach contents of two Cuvier’s beaked whales (Ziphius cavirostris) stranded in the Adriatic Sea

The stomach contents of two Cuvier’s beaked whales (Ziphius cavirostris) stranded along the eastern Adriatic coast were examined. One was a male stranded in 2004 and the other was a newborn stranded in 2008. Milk was found in the newborn’s stomach. The prey of the male was only cephalopods belonging mainly to the Teuthoidea. Five families and seven species were identified. Octopoteuthis sicula represented about 50% of estimated prey weight and Chiroteuthis veranyi was the most frequent species (estimated from the quantity of lower beaks). Three species are not listed in the Adriatic fauna, while the other species are found in middle and lower slope cephalopod assemblages in the southern Adriatic Sea.

Histological structure of the adrenal gland of the bottlenose dolphin (Tursiops truncatus) and the striped dolphin (Stenella coeruleoalba) from the Adriatic Sea.

The structure of the adrenal gland was studied in 11 bottlenose dolphins (Tursiops truncatus), and five striped dolphins (Stenella coeruleoalba). These species are legally protected in Croatia. All examined animals died of natural causes and were found stranded along eastern Adriatic coast. In both species the adrenal gland consists of a cortex and a medulla; the cortex is divided into three zones. Whereas in the bottlenose dolphin, there is a zona arcuata which contains columnar cells arranged in the form of arches; in the striped dolphin this zone is replaced by zona glomerulosa containing rounded clusters of polygonal cells. In both species, the zona fasciculata consists of radially oriented cords of polygonal cells, whereas in zona reticularis cells are arranged in branching and anastomosing cords. The adrenal medulla in both species contains dark, epinephrine‐secreting cells and light norepinephrine‐secreting cells. Epinephrine‐secreting cells are localized in the outer part of the medulla, whereas norepinephrine‐secreting cells are found in the inner part, arranged in clusters and surrounded by septa of thin connective tissue. The gland is surrounded by a thick connective‐tissue capsule, from where thick trabeculae extend towards the interior. In the bottlenose dolphin, group of cells resembling both medullar and cortical cells can be seen within the capsule; whereas only groups of cells resembling cortical cells are found within the capsule of the striped dolphin. In the bottlenose dolphin invagination of the adrenal cortex into the medulla is obvious as well as medullary protrusions extending through cortex to the connective tissue capsule.