Taryn Murray (PDP Post Doctoral Fellow)

PDP Post Doctoral Fellow
Taryn Murray (PDP Post Doctoral Fellow)


 

Ecology and movement behaviour of a piscivorous predator, leervis Lichia amia (Pisces: Carangidae).

Leervis (Lichia amia) is an estuary-dependent fishery species being distributed, in South Africa, from Cape Point to Cape Vidal. Due to the leervis’s popularity as a sport fish (targeted by all facets of South Africa’s recreational linefishery) and a perceived decline in abundance, this has led to concern over the leervis’s status in South African waters.

Although the biology and population dynamics of this species have been well-documented, limited information exists on the spatial and temporal movement behaviour of leervis – this being essential for fisheries management. In order to investigate movement behaviour and estuarine-dependency of leervis, acoustic telemetry and conventional mark-recapture methods. To elucidate estuarine movement patterns, a detailed telemetry study will take place in the Kowie Estuary, with acoustic receivers being deployed along the length of the estuary.

Additionally, environmental conditions will be recorded to determine the influence environmental factors have on the estuarine movements of juvenile leervis. Listening stations have already been deployed in the mouths of several adjacent estuaries (e.g. Sundays, Gamtoos, Kromme, Swartkops, Kariega, Great Fish) as well as the Coega and PE Harbours. This will be used to determine the extent of exchange between the different estuaries. Furthermore, 20 adult leervis will be tagged with V16 acoustic coded transmitters (5-year lifespan) and will be monitored for a minimum of two years. Curtains of acoustic receivers, all forming part of South Africa’s Acoustic Tracking Array Platform, will detect these tags and this information will be used to identify potential spawning areas and to assess the homing capabilities of adult leervis.

This study to obtain empirical data on the movement patterns of leervis will not only improve our scientific knowledge, but will provide information to assist with important management decisions of this estuarine-dependent species.  

Registered: Rhodes University (Department of Ichthyology and Fisheries Science)

Supervisor: Prof Paul Cowley (SAIAB)