Nine-spined Stickleback Pungitius Pungitius Research Articles

Orosensory food testing in fish: Chronology of behavior

The orosensory food testing behavior in fish was studied using the nine-spined stickleback Pungitiuspungitius as an example. The patterns of the chronology of manipulations performed by fish in testing food objects were identified. The existence of two stereotypical patterns of feeding behavior was confirmed, and their new characteristics were obtained. The relationship between the responsiveness to food and the predisposition of fish to feeding was revealed.

Influence of fish on the breeding of the red-necked grebe Podiceps grisegena (Boddaert, 1783)

I determined whether selection of breeding sites by thered-neckedgrebe Podiceps grisegena (Boddaert, 1783) was affectedbycompetition for food with fish. During 1987–89, ten ponds inScania, southern Sweden were investigated, five with(‘breedingsites’) and five without breeding red-necked grebe(‘non-breedingsites’). I quantified the biomass of fish and macrozoans(here:larger invertebrates and small vertebrates) and measured thephysical and chemical conditions of the ponds.Breeding sites had significantly lower relative fish abundancethannon-breeding sites. They were either devoid of fish or hadonly nine-spined sticklebackPungitius pungitius. The biomass (dry weight) ofmacrozoans,many of which represent a food resource for grebes, was 16timesgreater at breeding than at non-breeding sites. The physicalandchemical conditions of the ponds did not differsignificantly.These results are consistent with the hypothesis thatcompetitionfor macrozoans occurs between red-necked grebe and fish andthat adense population of many fish species caused red-necked grebestoavoid otherwise acceptable breeding sites.

Feeding activities of two euryhaline small-sized fish in a western Baltic brackish fjord

The daily food intake and feeding activities of the common gobyPomatoschistus microps (Kroyer) and the nine-spined sticklebackPungitius pungitius (L.) were investigated in the brackish Schlei fjord. At the investigation site of Olpenitz, salinities varied between 11 and 15‰, and water temperatures between 5 and 18°C during the period of in-situ experiments in 1981 and 1982. Common gobies sometimes attained a density of more than 100 individuals per square metre, nine-spined sticklebacks as much as 18 individuals per square meter. Their food changed depending on the supply of plankton or benthos. Regarding numbers, their food consisted mainly of harpacticoids, in springtimes of calanoids; with regard to weight, amphipods, polychaetes or chironomid larvae often prevailed. The total food ingestion, measured by means of its relation to fish weights (fullness index), was highest in spring and summer: 2.3% inP. microps and 2.6% inP. pungitius. Low fullness indices of 0.8% inP. microps and 0.3% inP. pungitius were found during times of low water temperatures. 24-h field investigations revealed that the adultP. microps presented clear diurnal rhythms with highest fullness indices after dawn and a further maximum at dusk. Only young gobies ingested some benthos at night.P. pungitius displayed similar rhythms in which maximum fullness indices varied during the day. This species seems to forage every four hours. At dusk, both species preferred benthos to plankton. The results are discussed with respect to the implications of diurnal and seasonal fluctuations in prey choice by small-sized fish populations.