Publication Date:
2014-12-19
Description:
Previous work has shown that the invasive bivalve Limnoperna fortunei has had a measurable impact on local food webs, but knowledge of the trophic interactions involved is still very limited. On the basis of samples collected along the lower Paraguay-middle Paraná rivers, we studied the feeding behavior and selectivity of larval fish, with emphasis on veligers of the introduced bivalve L. fortunei . Among feeding larvae (i.e., without a yolk sac), 16.5% had only Limnoperna veligers in their guts, while 15.6% had veligers and some other prey. Half of the fish taxa recorded (8 out of a total of 16) consumed Limnoperna veligers. The Paraguay and Paraná rivers differed strongly in the proportions of fish larvae that consumed veligers: 14 and 68%, respectively. This difference paralleled the availability of veligers in the water column, which was significantly lower in the Paraguay (0.8 ± 0.5 ind. l −1 ) than in the Paraná River (5.5 ± 2.3 ind. l −1 ). Conversely, cladocerans, originally the staple food of fish larvae, were more abundant in the Paraguay (consumed by 48% of the individuals) than in the Paraná River (26%). These results indicate that, when widely available, Limnoperna veligers largely replace the original prey of fish larvae, especially in their younger stages (protolarvae).
Print ISSN:
0018-8158
Electronic ISSN:
1573-5117
Topics:
Biology
Permalink