Food selection of burbot (Lota lota L.) larvae reared in illuminated net cages in mesotrophic Lake Maróz (north-eastern Poland)

Abstract

Feeding and food selection of burbot (Lota lota L.) larvae reared in illuminated cages were studied. The experiment was carried out in mesotrophic Lake Maróz, in northeastern Poland, for 6 weeks in two successive years. The initial stocking density was 1,250 larvae (20 DPH) per cage. Food selection according to the zooplankton groups (Rotifera, Cladocera and Copepoda) and length classes was expressed by the Strauss linear selectivity index (L). Zooplankton species composition in the lake was similar in the two seasons of the study and organisms shorter than 0.5 mm prevailed in the plankton. The mean number of prey found in burbot alimentary tracts increased from about 40 up to over 200 during the course of the study. A very large inter-individual variation in the amount of food organisms consumed by fish was noted. Analysis of the values of the Strauss food selectivity index shows that at the beginning of the first year of the experiment, burbot larvae preferred copepods, most numerous in the environment at that time; later, fish tended to select cladocerans. In the second year of the study, fish more often ate copepods, irrespective of their quantities in the environment. During the whole study, reared burbot larvae did not eat rotifers, even when they were numerous in cages. Similarly to the rotifers, the smallest planktonic organisms, measuring up to 0.5 mm in length, were typically neglected by fish, while the 0.6-1.0 mm group was most frequently selected. There were also considerable individual differences between particular burbot specimens in their food preferences.

Selective feeding of the mullet larvae Liza haematocheila during ontogeny in Laizhou Bay, Bohai Sea, China: The importance of small copepods in mesozooplankton as prey

“…Feeding and foraging successfully during the larval stage is critical to fish survival (Devries et al, 1998;Skrzypczak et al, 1998). Many factors affect the success of larval predation, including the ability of the predator to consume its prey, morphological constraints during ontogeny, and prey size and abundance (Furgała-Selezniow et al, 2014). It has been reported that fish larvae are gap-limited predators, and they usually swallow prey whole when foraging.…”

A study of the feeding characteristics of a small and medium-sized copepod species (Sinocalanus tenellus) using genetic analysis techniques: seasonal comparison of potential/eaten food sources focused on phytoplankton

“…The traditional method to analyze the feeding characteristics of organisms is to identify the gut contents via the naked eye or with a microscope (Chang et al, 2011;Furgała-Selezniow et al, 2014). However, these methods have limited results because they can be derived from the decomposition of feeding sources remaining in the gut.…”

Downstream migration of Burbot Larvae (Lota lota) in the section of the Irtysh River

“…In addition, seasonal periods of its maximum migratory activity for adults have been established [1]. In some countries, this species is included in the Red Data Book of ichthyofauna [5].…”