In support of the IOTC ecosystem report card: indicators for non- retained sharks and rays

In this working paper, we address the ecosystem component consisted of “nonretained sharks and rays” to support the development of an ecosystem report card in the IOTC region. This group includes sharks and ray species that are not retained due to retention bans or due to their low or no commercial value. The interaction between these non-retained species and IOTC fisheries needs to be monitored because, in most cases, stock assessments have not yet been conducted due to lack of data and their status remain unknown or poorly known. The conceptual objective of this work is to reduce the interactions and mortality induced by IOTC fisheries to levels that would be sustainable for these species. The operational objective is to determine whether the number of interactions and total mortality is not jeopardizing the reproductive capacity of the species. To do so, we propose a list of candidate indicators to be calculated for key species and fishing gears. Two examples of indicator trends derived from purse seine data are presented and briefly discussed. Future steps include making an inventory of available data sources by species, updating the list of priority species by gear type, exploring indicators for species for which data is available and defining periodicity for the indicator assessments. The work presented here is still in progress and requires the collaboration of multiple experts with experience on the multiple gears operating in the IOTC convention area. We invite the IOTC community to contribute towards the development of this ecosystem component to support the IOTC ecosystem report card.