The Life History of the Southern Lanternshark, Etmopterus granulosus, from the Southwestern Indian Ocean

The Southern Lanternshark, Etmopterus granulosus, is a deep-sea shark that associates with seamounts and ridges between 220-1500 m throughout the southern oceans. Though not a targeted species, it is frequently incidentally caught in several fisheries, and comprises the highest amount of bycatch by number in the Orange Roughy (Hoplostethus atlanticus) fishery in the Southwestern Indian Ocean. Despite how frequently this species is encountered, surprisingly little is known about it beyond basic biology. The lack of life history information is partially attributed to the difficulty in obtaining samples and is compounded by a lack of methods to appropriately assess traditional life history parameters, such as age and growth. To better understand the life history of this species, genetic techniques were used to examine its mating system and to assess whether an alternative ageing method could be developed. The use of microsatellite markers to examine the mating system showed that polyandry was present in 33% of the litters. However, the frequency of multiple paternity and its comparison to other aspects of the breeding biology of this species do not fit within the usual elasmobranch paradigms. The use of qPCR to measure telomere length showed that telomeres appear to shorten with increased length (p= 0.0007). Though more work will need to be done to develop this as an ageing method, it may help to develop understanding of elasmobranch life history outside of traditional parameters