Small-sized euryhaline fish as intermediate hosts of the digenetic trematodeCryptocotyle concavum

Helgolander Meeresunters

Strohbach

Groenewold

1993

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The parasite fauna of five goby species (Gobiidae, Teleostei) was investigated in the Baltic Sea during the period 1987 to 1990. 13 parasite species were found in samples from the (Acanthocephala). The number of parasite species were: 10 in the sand goby Pomatoschistus minutus, 8 in the black goby Gobius niger, 7 in the two-spotted goby Gobiusculus flavescens, 6 in the common goby Pomatoschistus microps, and 5 in the painted goby Pomatoschistus pictus. Neoechinorhynchus rutili occurred only in P. minutus, and Corynosoma sp. only in G. niger. The extent to which the gobies were parasitized clearly depended on the respective ways of life and, moreover, on the kind of prey ingested by the hosts. Additionally, the age of the hosts might be important. The highest rate of parasitism, more than 60 %, was reached by Hysterothylacium sp. in G. niger and by Cryptocotyle concavum in P. microps. Infestation incidence lay mostly below 40 % which means a satellite species status (Holmes, 1991). The number of parasite species was highest in summer; the highest intensities of single parasites occurred in spring (Podocotyle atomon) or autumn (Cryptocotyle concavum). Bothriocephalus scorpii, Hy, sterothylacium sp. and Podocotyle infested their juvenile hosts very early, but only I-Iysterothylacium was accumulated by G. niger during its whole life span, whereas Bothriocephalus persisted also in older gobies in low intensities. The cercariae of Cryptocotyle spp. penetrate actively into their hosts; ai1 the other parasites named were transmitted in larval form by prey organisms which consisted mainly of planktonic and benthic crustaceans. The gobies were final hosts for only 5 parasites; but two species may be transmitted to larger fish, and 6 species to sea birds or mammals. The parasite community of the five gobies may possibly be taken to characterize the ecological quality of the environment of the Liibeck Bight.

Section: % Pminufus 1988 (I]8) V L R---n V--i ~mentioning

confidence: 99%

Section: The Dynamics Of Parasite Communitymentioning

confidence: 99%

Section: Life Cyclesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Several authors thereafter studied the parasitic faunas of single fish hosts (e.g. M6ller, 1975;Kgie, 1983), or the host spectra of single parasites (K~ie, 1979;Zander et al, 1984).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

The importance of gobies (Gobiidae, Teleostei) as hosts and transmitters of parasites in the SW Baltic

Helgolander Meeresunters

Strohbach

Groenewold

1993

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Alteration of the Metazoan Parasite Faunas in the Brackish Schlei Fjord (Northern Germany, Baltic Sea)

Kesting

Internat. Rev. Hydrobiol.

2000

Parasite communities of the inner and middle Schlei Fjord were investigated from 1992 to 1994. Host groups, comprising small‐size or young fishes, benthic and planktonic crustaceans, and snails were taken from 4 localities (Selk, Haddeby, Borgwedel and Missunde) of differing salinities (1–8 ‰). The host and parasite fauna turned out to be very sparse, comprising 10 (Selk) to 16 (Missunde) host species of which only 7 and 9, respectively, harboured parasites. Parasites numbered 4 in Selk and 8 in Borgwedel and Missunde. Hysterothylacium sp. (Nematoda) was the only parasite present in all localities. High prevalences were attained by Proteocephalus percae (Cestoda) and Cryptocotyle concavum (Digenea) in Borgwedel and Missunde, whereas in Selk and Haddeby Caligus lacustris prevailed. With the exception of Cryptocotyle concavum intensities were mostly 1, and multiple infestations were rare. On the basis of comparisons with former investigations a faunal impoverishment can be stated during the course of 18 years in the inner Schlei Fjord. Increasing eutrophication causing deep mud layers on the bottoms as well as the ensuing high oxygen deficiencies even in the free water column during summer and autumn can be possible reasons for this phenomenon. As further consequence, the parasite spectrum was reduced to species which have simple developmental cycles and to species which prefer planktonic or suprabenthic, not benthic, hosts. The environment in Missunde with salinities of 6–8 ‰, can be designated as that described by Remane as an area of species minimum. In former times the parasite communities in Missunde were characterised by a species richness which was in contrast to the abundance of free living organisms.

Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea

Helgolander Meeresunters

Groenewold

Strohbach

1994

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Four helminth parasites out of 19 species found in the Liibeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atornon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Garnmarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pornatosctn'stus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.