Trophic ecology of an abundant predator and its relationship with fisheries

BARNETT, A.; YICK, J.; ABRANTES, K.; AWRUCH C. A.

MARINE ECOLOGY PROGRESS SERIES

INTER-RESEARCH

Lugar: Oldendorf/Luhe; Año: 2013 vol. 494 p. 241 - 248

0171-8630

Trophic studies are key components in animal ecology and fisheries research.Although stomach samples are often obtained from fisheries, diet studies that consider the influenceof fisheries on dietary results are still lacking. Here, the diet of the draughtboard sharkCephaloscyllium laticeps, an abundant mesopredator in Tasmanian waters, was investigated.Stomach samples were obtained from gillnet and craypot fisheries sourced from 4 regions: central(100% gillnet), east coast (63% gillnet, 37% craypot), northwest (100% gillnet), and southwestTasmania (100% craypot). Overall, C. laticeps consumed the same prey types in all regions, butthe importance of some prey varied significantly between regions. Generalized linear modelsshowed that region was the main factor affecting prey abundance in the diet. Fishing method hadsome influence on the abundance of some prey (crabs, octopus, and other molluscs (gastropodsand bivalves)), but the effect of fishing method on pot-related species such as Jasus edwardsii(lobster) and octopus was not as prevalent as expected. The common occurrence of C. laticeps asa bycatch species and its high consumption of targeted fishery species (lobsters and octopus) indicatesthat C. laticeps has a strong interaction with the fisheries. Therefore, the relationshipbetween these fishery species and C. laticeps should be considered in food web studies inTasmanian waters.