Terrestrial prey, an important part in Salmo trutta diet or a stochastic event?
2023
Аутори:
Čanak Atlagić, JelenaMarić, Ana
Marinković, Nikola
Đuknić, Jelena
Anđus, Stefan
Ilić, Marija
Tubić, Bojana
Stojanović, Katarina
Paunović, Momir
Simonović, Predrag
Тип документа:
Конференцијски прилог (Објављена верзија)
,
© 2023 by the European Ichthyological Society
Метаподаци
Приказ свих података о документуАпстракт:
The brown trout is a valuable species for recreational fishing and its diet is of great interest. It feeds on
various aquatic invertebrates, but also consumes terrestrial prey, whose contribution is often unjustly
underestimated. The importance of terrestrial prey in diets of two trout populations was assessed at two
sites (April-October) with different quantity of available aquatic prey (Site 1 high, Site 2 low quantity).
Four indices of importance were used: frequency of occurrence (FO), number of prey items (AN), weight
(AW), and index of relative importance (IRI). Preference for terrestrial prey was also estimated based on
the electivity index (EI), where the availability of aquatic and terrestrial prey was expressed as their
percentage in the drift samples.
Significantly less terrestrial prey was available at Site 1 (0.39% ± 0.57%) in contrast to Site 2 (13.21% ±
10.38%), terrestrial prey was significantly more abundant in the trout diet than in the drift samples at
both sites (t test). The EI was positive for terrestrial prey, additionally FO showed that this prey was
present in 36% ± 16.65% (site 1) and in 87.55% ± 8.94% individuals (site 2), indicating a high preference for
this type of prey. The importance (IRI) of terrestrial prey was higher than expected at Site 1 (1.39% ±
1.53%; maximum 4.7% in September) and high at Site 2 (58.6% ± 23.56%; maximum 84.67% in
September). Terrestrial prey became more present in the drift and more important in the diet toward the
end of the study period, while the importance of aquatic prey decreased based on all four indices at both
sites. The correlation between the increasing importance of terrestrial prey (AN, IRI) in the diet and the
presence of aquatic prey in the drift (%) towards the end of the season was not significant (Pearson). Thus,
the positive trend in the importance of terrestrial prey may be due to their increasing availability and
simultaneous decline of large prey in the aquatic community due to the emergence of adults.
Terrestrial prey is generally larger (i.e., yielding more energy) than most aquatic prey and easily captured
due to its low mobility in the aquatic environment. In the habitat with low availability of aquatic prey,
terrestrial prey played an important role in brown trout diet. In addition, brown trout also preferred it in
the habitat rich in aquatic prey. This study shows that terrestrial prey is significant brown trout feeding
resource regardless of its general availability in the environment.
Кључне речи:
brown trout diet; terrestrial prey; aquatic prey; prey importance; selective predationФинансирање / пројекти:
- Министарство науке, технолошког развоја и иновација Републике Србије, институционално финансирање - 200007 (Универзитет у Београду, Институт за биолошка истраживања 'Синиша Станковић') (RS-MESTD-inst-2020-200007)
У:
- Abstract book: 17th European Congress of Ichthyology; 2023 Sep 4-8; Prague, Czech Republic. European Ichthyological Society; 2023. p. 104.