Preliminary analysis of observer data on the presence of mesh in floating objects used by the French purse seine fleets in the Atlantic and Indian Oceans

We conducted an initial analysis using data from observers aboard French
PS vessels in the Atlantic and Indian Oceans of the composition of FOBs
deployed, fished and encountered by the French fleet focusing on the use of
netting. Data before 2019 are insufficient for assessing the presence of netting
as fields for noting this type of information were only added to observer data
protocols and data entry platforms in 2019. There are also a number of
caveats to using this data for assessing the prevalence of netting in FOBs
due to the data collection protocol used by observers on French vessels and
observed differences in rates of FOBs with netting as a function of observer
program and observer country of origin. Nevertheless, our observations are
globally consistent with both independent analyses of dFAD composition in
the Indian Ocean and more anecdotal observations of dFADs found in coastal
environments in the Indian Ocean. Non-negligible numbers of FOBs with
netting were recorded in 2019-2020, but rates decline significantly in 2021-
2022, with average rates across observer programs being on the order of 3-5%
for both ocean and both years. Non-zero levels of netting are observed in both
dFADs and other objects of natural or human origin. Consistent differences
in observation rates across observer programs and observer countries of origin
suggest that more consistent training and changes in the observation protocol
for the French fleet are needed to more accurately estimate the composition
of FOBs used by EU PS vessels. Given the confusion that could be caused by
PS vessels fishing upon or deploying tracking buoys upon non-dFAD objects
that may contain netting (e.g., FALOGs), it would potentially be valuable
to implement a policy of not attaching tracking buoys to these objects and
removing them from the water when encountered.