Predicting impacts of invasive Tench across habitat types

Partie de:
jeudi 19 déc. 09:15 AM (15 minutes)
Salle CD

Predicting impacts of introduced fishes is key to informing management decisions. Such predictions are challenging because impacts are often poorly documented and highly context dependent across the invaded range. An increasingly used method for quantifying and comparing per capita impacts of invaders under different ecological contexts involves measuring the invader’s rate of predation in relation to available prey density – i.e. its functional response. We compared functional response curves for Tench (Tinca tinca) on different substrates and two temperatures. Published studies consistently report Tench in association with soft sediments, implying the species might be an inefficient predator on coarser substrates where prey have increased access to refugia and, therefore, a weak competitor to native fishes typically found in rocky littoral habitats. Our experiments suggest Tench consumption rates are not impaired on rocky substrates. Further evidence is provided by a complementary mesocosm experiment which revealed that Tench growth is not dependent on substrate size. Finally, we examined the interacting effects of substrate and temperature on Tench to determine whether increasing water temperatures alter the influence of substrate on Tench functional response.

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