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Crayfish in lakes and streams: individual and population responses to predation, productivity and substratum availability

Nyström, Per LU ; Stenroth, Patrik LU ; Holmqvist, Niklas LU ; Berglund, Olof LU ; Larsson, Per LU and Granéli, Wilhelm LU (2006) In Freshwater Biology 51(11). p.2096-2113
Abstract
1. In a correlative study, we investigated the relative importance of fish predation, refuge availability and resource supply in determining the abundance and size distributions of the introduced and omnivorous signal crayfish (Pacifastacus leniusculus) in lakes and streams. Moreover, the biomass and food selection of predatory fish was estimated in each habitat type and stable isotopes of carbon and nitrogen were measured in perch (Perca fluviatilis), the dominant predator in the lakes, and in its potential food sources (crayfish, juvenile roach and isopods).

2. In lakes, crayfish were the most frequent prey in large perch (46%), followed by other macroinvertebrates (26%, including the isopod Asellus aquaticus) and small fish... (More)
1. In a correlative study, we investigated the relative importance of fish predation, refuge availability and resource supply in determining the abundance and size distributions of the introduced and omnivorous signal crayfish (Pacifastacus leniusculus) in lakes and streams. Moreover, the biomass and food selection of predatory fish was estimated in each habitat type and stable isotopes of carbon and nitrogen were measured in perch (Perca fluviatilis), the dominant predator in the lakes, and in its potential food sources (crayfish, juvenile roach and isopods).

2. In lakes, crayfish were the most frequent prey in large perch (46%), followed by other macroinvertebrates (26%, including the isopod Asellus aquaticus) and small fish (25%). Crayfish and fish dominated the gut contents of large perch with respect to biomass. Nitrogen signatures showed that perch were one trophic level above crayfish (approx. 3.4 parts per thousand) and a two-source mixing model using nitrogen isotope values indicated that crayfish (81%) contributed significantly more to perch isotope values than did juvenile roach (19%). A positive correlation was found between the abundance of crayfish and the biomass of large perch. Crayfish abundance in lakes was also positively correlated with the proportion of cobbles in the littoral zone. Lake productivity (chlorophyll a) was positively correlated with crayfish size, but not with crayfish abundance.



3. In streams, brown trout (Salmo trutta) were the most abundant predatory fish. Gut contents of large trout in a forested stream showed that terrestrial insects were the most frequently found prey (60%), followed by small crayfish (27%) and isopods (27%). In contrast to lakes, the relative abundance of crayfish was negatively correlated with the total biomass of predatory fish and with total biomass of trout. However, abundance of crayfish at sites with a low biomass of predatory fish varied considerably and was related to substratum grain size, with fewer crayfish being caught when the substratum was sandy or dominated by large boulders. The mean size of crayfish was greater at stream sites with a high standing stock of periphyton, but neither predator biomass nor substratum grain size was correlated with crayfish size.



4. Our results suggest that bottom-up processes influence crayfish size in lakes and streams independent of predator biomass and substratum availability. However, bottom-up processes do not influence crayfish abundance. Instead, substratum availability (lakes) and interactions between predation and substratum grain size (streams) need to be considered in order to predict crayfish abundance. (Less)
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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Freshwater Biology
volume
51
issue
11
pages
2096 - 2113
publisher
Wiley-Blackwell
external identifiers
  • wos:000241190900010
  • scopus:33749834346
ISSN
0046-5070
DOI
10.1111/j.1365-2427.2006.01641.x
language
English
LU publication?
yes
id
fc51bfe2-e1b8-4f12-bda3-abc00d01eaed (old id 162776)
date added to LUP
2016-04-01 15:28:15
date last changed
2024-01-10 15:25:09
@article{fc51bfe2-e1b8-4f12-bda3-abc00d01eaed,
  abstract     = {{1. In a correlative study, we investigated the relative importance of fish predation, refuge availability and resource supply in determining the abundance and size distributions of the introduced and omnivorous signal crayfish (Pacifastacus leniusculus) in lakes and streams. Moreover, the biomass and food selection of predatory fish was estimated in each habitat type and stable isotopes of carbon and nitrogen were measured in perch (Perca fluviatilis), the dominant predator in the lakes, and in its potential food sources (crayfish, juvenile roach and isopods). <br/><br>
2. In lakes, crayfish were the most frequent prey in large perch (46%), followed by other macroinvertebrates (26%, including the isopod Asellus aquaticus) and small fish (25%). Crayfish and fish dominated the gut contents of large perch with respect to biomass. Nitrogen signatures showed that perch were one trophic level above crayfish (approx. 3.4 parts per thousand) and a two-source mixing model using nitrogen isotope values indicated that crayfish (81%) contributed significantly more to perch isotope values than did juvenile roach (19%). A positive correlation was found between the abundance of crayfish and the biomass of large perch. Crayfish abundance in lakes was also positively correlated with the proportion of cobbles in the littoral zone. Lake productivity (chlorophyll a) was positively correlated with crayfish size, but not with crayfish abundance.<br/><br>
<br/><br>
3. In streams, brown trout (Salmo trutta) were the most abundant predatory fish. Gut contents of large trout in a forested stream showed that terrestrial insects were the most frequently found prey (60%), followed by small crayfish (27%) and isopods (27%). In contrast to lakes, the relative abundance of crayfish was negatively correlated with the total biomass of predatory fish and with total biomass of trout. However, abundance of crayfish at sites with a low biomass of predatory fish varied considerably and was related to substratum grain size, with fewer crayfish being caught when the substratum was sandy or dominated by large boulders. The mean size of crayfish was greater at stream sites with a high standing stock of periphyton, but neither predator biomass nor substratum grain size was correlated with crayfish size.<br/><br>
<br/><br>
4. Our results suggest that bottom-up processes influence crayfish size in lakes and streams independent of predator biomass and substratum availability. However, bottom-up processes do not influence crayfish abundance. Instead, substratum availability (lakes) and interactions between predation and substratum grain size (streams) need to be considered in order to predict crayfish abundance.}},
  author       = {{Nyström, Per and Stenroth, Patrik and Holmqvist, Niklas and Berglund, Olof and Larsson, Per and Granéli, Wilhelm}},
  issn         = {{0046-5070}},
  language     = {{eng}},
  number       = {{11}},
  pages        = {{2096--2113}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Freshwater Biology}},
  title        = {{Crayfish in lakes and streams: individual and population responses to predation, productivity and substratum availability}},
  url          = {{http://dx.doi.org/10.1111/j.1365-2427.2006.01641.x}},
  doi          = {{10.1111/j.1365-2427.2006.01641.x}},
  volume       = {{51}},
  year         = {{2006}},
}