Page 32 - Studia Universitatis Hereditati, vol 13(2) (2025)

Roman Portus, it is estimated that ships with a (LALIA from 536 to 660 AD) is considered to
draught of between 1.9 and 7 metres could fre- have been a period of turmoil in Europe, which
quent the harbour (Boetto 2010, table 1). Giv- caused human migrations and pandemics. The
en the shallow bottom of the Osor Channel and exact causes of the climate cooling are still not
the lower sea level of 1–1.5 m in Roman times determined exactly but a possible cause could be
(Vacchi et al. 2016; Marriner et al. 2014), large- a series of volcanic eruptions between 536 and
draught vessels may have been restricted on the 547 AD (Büntgen et al. 2016). The activities that
maritime route next to Osor. Stražičić (1995, 78– were producing the specific organic carbon foot-
9) suggested that using the tidal current or the print in Osor during the period of Subzone 22
higher sea level during high tide, or unloading abruptly stopped after the Late Antique Little
ships before crossing the canal, could have par- Ice Age. In order to confirm this, higher resolu-
tially mitigated this issue. However, as it is not tion dating in the transition from Subzone 22 to
32 possible to ascertain whether shipping was fea- Zone 3 is needed.
sible down to the bedrock in Roman times, any
further calculations regarding maritime traffic
studia universitatis hereditati, letnik 13 (2025), številka 2 / volume 13 (2025), number 2
are purely speculative. Harbours and Anchoring in Jaz and Bijar Bay
The steep decline in terrestrial organic car- Like many other parts of the Croatian coast,
bon in marine sediments after the Roman times the Kvarner Bay is a challenging sailing pas-
makes a monocausal explanation unlikely. Such sage on the route between Italy and Greece. The
an approach would be inaccurate as both nat- near-coastal Velebit massif is the area from which
ural and human influences may have played a the notorious cold northeasterly wind (Croat.
part in the history of the Osor Channel. From bura) originates, with gusts reaching almost 200
a historical perspective, there are numerous hu- km/h. The 16th century insult ‘damn the Kvar-
man-induced processes that could have contrib- ner having let you pass’ (Kozličić 2006, 84) viv-
uted to lower sedimentation rates in the Osor idly describes the region. The region is also influ-
Bay. Following two centuries of prosperity and enced by microtidal conditions with an average
continuous peace, Late Antiquity was marked amplitude of ~30 cm but the influence of atmos-
by a series of radical changes. For example, large- pheric pressure patterns together with predomi-
scale agricultural production in southern Istria nant winds enables the sea level to rise to 1.6 m
is believed to have ceased from Late Antiqui- above mean sea level (Benac et al. 2008b). This
ty period onwards, with communities then cul- illustrates the need for safe ports along the route
tivating a variety of products for personal con- between Istria and Dalmatia, and Osor was po-
sumption or sale within the region (Levak 2013). tentially one of them.
How the upheavals of the Late Antique period Most theories actually argued for two har-
affected small regions like the Kvarner Islands bours, one in the north located in the bay of Bi-
in terms of land use and trade, and more specif- jar (Faber 1980; Ettinger Starčić 2012) and one
ically the maintenance of the Osor Channel, re- south of the city walls in the bay of Jaz, now in-
mains unclear. filled (Faber 1980; Stražičić 1995). While the
Another possibility is the natural or delib- theory of a harbour in Bijar seems to be sup-
erate closure of the Osor Channel to shipping. ported by underwater finds, no archaeological
This would also explain the lower rate of sedi- proof, like firm evidence of port facilities, could
ment accumulation resulting from the short- be found for the Jaz Bay to date. A geophysical
or long-term destruction of the channel. In ad- survey of the coastal area between the Jaz Bay
dition, a climatic influence cannot be ruled out and the Lošinj Channel in spring 2024 discov-
and should be considered when analysing the ered building remains (forthcoming publica-
data. The so-called Late Antique Little Ice Age tion), but it is currently unclear whether these