0000000000283458
AUTHOR
Jouni Salonen
Jättikatkan (Gammaracanthus lacustris) ja jäännehalkoisjalkaisen (Mysis relicta) koko- ja tiheysjakaumat Saimaan Paasivedellä
Reliktisten makroäyriäisten elintapoja on tutkittu maailmanlaajuisestikin hämmästyttävän vähän eikä etenkään elinympäristönsä suhteen vaativana pidetystä jättikatkasta (Gammaracanthus lacustris) ole tehty julkaisuja juuri lainkaan. Tutkimuksen tavoitteena oli selvittää lajin syvyyskohtaisia koko-, tiheys- ja sukupuolijakaumia sekä eri vuosien ja alueiden välisiä eroja Saimaan Paasivedellä. Lokakuussa 2006 – 2008 30 m alapuolisista vesikerroksista otetuista näytteistä saatiin samalla tietoa myös jäännehalkoisjalkaisen (Mysis relicta) vertikaalijakaumista samoissa olosuhteissa. Myös oka- (Pallaseopsis quadrispinosa) ja valkokatkaa (Monoporeia affinis) tavattiin joitakin yksilöitä. Mahdollises…
Interaction between the endangered freshwater pearl mussel Margaritifera margaritifera, the duck mussel Anodonta anatina and the fish host (Salmo) : acquired and cross-immunity
The common duck mussel Anodonta anatina can live in sympatry with—and use the same host, brown trout (Salmo trutta)—as the endangered freshwater pearl mussel Margaritifera margaritifera. Since the glochidia release of A. anatina takes place seasonally earlier than that of M. margaritifera, brown trout can be sequentially exposed first to A. anatina and then to M. margaritifera. Cross-immunity, an immune reaction induced in fish host against glochidia after the infection with glochidia of another mussel species, is possible. Thus, it was studied experimentally if brown trout can be cross immunized against M. margaritifera by earlier infection with A. anatina. In addition, the hypothesis that…
Makroäyriäisten (Gammaracanthus lacustris, Mysis relicta, Monoporeia affinis, Pallaseopsis quadrispinosa) vuorokausivaellukset Saimaan Paasivedellä; Diel vertical migrations of the macroscopic crustaceans Gammaracanthus lacustris, Mysis relicta, Monoporeia affinis and Pallaseopsis quadrispinosa in Lake Paasivesi, Saimaa
We examined the diel vertical migrations of the macroscopic pelagic relict crustaceans Gammaracanthus lacustris, Mysis relicta, Monoporeia affinis and Pallaseopsis quadrispinosa in the deep Lake Paasivesi basin of the Saimaa lake complex. The samples were collected in October 2006 and 2007 using a Hydro-Bios Multi Plankton Sampler onboard the research vessel R/V Muikku. The study provides information about the day-and-night and year-to-year changes in the vertical distribution of these crustaceans. Regarding G. lacustris we explored if body size (length), sex or maturity have bearing on the individuals' depth preference or possible diel migrations. We noticed that G. lacustris females occur…
Jättikatkan (Gammaracanthus lacustris) ja jäännehalkoisjalkaisen (Mysis relicta) koko- ja tiheysjakaumat Saimaan Paasivedellä; Vertical size and density distributions of Gammaracanthus lacustris and Mysis relicta in Paasivesi, Lake Saimaa
The ecology of relict crustaceans in Finnish lakes is quite poorly known. In this study we investigated the vertical distributions of these species in Lake Saimaa in the depth zones between 30 m and 60 m. We found out that Gammaracanthus. lacustris lives mainly in the deepest parts of the lake, while Mysis relicta favours the shallowest zones. The average length of both species increased with the depth in the study area. There were some differences in distributions between years, but the main reasons for that are not known exactly. peerReviewed
Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) differ in their suitability as hosts for the endangered freshwater pearl mussel (Margaritifera margaritifera) in northern Fennoscandian rivers
1. European populations of the freshwater pearl mussel (FPM, Margaritifera margaritifera) have widely collapsed, and despite many types of conservation actions the number of successful restoration trials has remained limited. The goal of this study was to find new aspects for the conservation by investigating whether there are population-specific differences in suitability of Atlantic salmon (Salmo salar) and brown trout (S. trutta) as the hosts for the parasitic glochidium larvae of FPM, depending probably on the historical occurrence of these salmonid species in FPM habitats. 2. We studied the potential host specificity both in the field and in laboratory by exposing salmonid fish to FPM …
The role of salmonid fishes in conservation of the endangered freshwater pearl mussel (Margaritifera margaritifera)
The abundance of freshwater pearl mussels (Margaritifera margaritifera) has declined widely during the past century, and new conservation initiatives are needed. This thesis focused on the relationship between M. margaritifera and its salmonid host required for reproduction of this species. First, by exposing fish experimentally to glochidium larvae of M. margaritifera, different M. margaritifera populations were shown to demonstrate strong differences in their ability to parasitize different salmonid species. Atlantic salmon was clearly a better host for mussels in large river channels, whereas in small headwater tributaries brown trout was the best, or the only suitable, host. These findi…
Electrofishing as a new method to search for unknown populations of the endangered freshwater pearl mussel Margaritifera margaritifera
1. The freshwater pearl mussel Margaritifera margaritifera is threatened throughout its Holarctic range, but the occurrence of this species is insufficiently mapped. For the conservation of M. margaritifera, it is important to identify populations more comprehensively. 2. Traditionally mussels have been searched for visually using techniques such as diving and aquascope, both of which are potentially time-consuming and demanding survey methods. 3. In this study, a new search method is presented. As glochidia of M. margaritifera are larval parasites on gills of salmonid fish, electrofishing and non-destructive examination of salmonids with the naked eye may reveal the presence of glochidia a…