Niche Dynamics and Resource Partitioning in a Fish Guild Inhabiting a Shallow Estuary on the Swedish West Coast

Thorman, Staffan

doi:10.2307/3544528

Cited by 38 publications

(24 citation statements)

References 10 publications

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“…Since few other fi.sh species were caught, the principal competition for prey would be between cod and haddock. Such convergence of diet when prey are abundant, and separation when prey are scarce has been noted by Harrington & Harrington (1961) for fishes feeding on mosquito larvae in coastal salt marshes, and by Thorman (1982) for estuarine fish species on the west coast of Sweden. Courtois et al (1982) have also concluded that vertical separation results in reduced interspecific competition of fish larvae in the St Lawrence Rlver estuary.…”

Section: Discussionmentioning

confidence: 52%

Vertical distributions and trophic interactions of age-0 Atlantic cod and haddock in mixed and stratified waters of Georges Bank

Perry¹,

Neilson²

1988

Mar. Ecol. Prog. Ser.

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ABSTRACT, Die1 changes in the vertical distribution of age-0 (post-laival) Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus were examined in isothermal and stratified waters of Georges Bank in June 1985. Discrete depth collections every 4 h ~ndicated that changes in depth were more extensive for cod than haddock. At both sites, cod were predominately near bottom during the day and in midwater at night, although at the stratified site this upward migration may have been limited by the thermocline. Age-0 haddock at the stratified site occurred about the thermocline with little die1 change of depth. At the mixed site, haddock were distributed predominately near bottom but were caught throughout the water column during the periods before noon and midnight. Small cod and haddock (<30 mm standard length for cod, <40 mm for haddock) were distributed at shallower depths and undertook less extensive migrations than larger fish. Relationships of temperature, salinity, light, tidal current speed and preferred zooplankton prey to the changes in depth distributions were examined. Vertical migrations of cod were related to the die1 light cycle at both sites. At the mixed site, the number of haddock caught was inversely related to the mean tidal current speed during the sampling period. Preferred prey, especially the mysid Neomysis americana, may have moved into midwater w~t h haddock during slackened currents, remaining near bottom with cod at other times in daylight. Zooplankton biomass and physiological condition (as Fulton's K) of cod and haddock were significantly greater at the mixed site. Electivity indices indicated that N. americana, which occurred at high densities, was the preferred prey of both fish species at this site. At the stratified site, cod and its preferred prey Tisbe sp. were both distributed in deep water, while haddock and its preferred prey Limacina sp. CO-occurred in near-surface waters. The similar distributions of cod and haddock when prey were plentiful, and separate distributions when prey were scarce, may have served to reduce interspecific competition. Adequate prediction of haddock vertical distributions for survey purposes may require knowledge of thermal structure, distribution of prey, and tidal current speed.

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Section: Discussionmentioning

confidence: 52%

Vertical distributions and trophic interactions of age-0 Atlantic cod and haddock in mixed and stratified waters of Georges Bank

Perry¹,

Neilson²

1988

Mar. Ecol. Prog. Ser.

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“…Healy 1971, Vaas et al 1975, Nash 1982 & Gibson 1982, Vesey & Langford 198.5, Hamerlynck et al 1986, Doornbos & Twisk 1987. beach seine catches (Nash 1984(Nash ,1988, and drop-traps or drop-nets (Aneer & Nellbring 1977, Evans & Tallmark 1979, Phil & Rosenberg 1982, Thorman 1982, Phil Baden & Phil 1984, Thorman & Wiederholm 1984, Nellbring 1985. Doornbos & Twisk (1987) reviewed estimates of densities of Pomatoschistus minutus (0.14 to 12.7m-') and P. pictus (0.1 to 25.0m-?).…”

Section: A Bundancementioning

confidence: 99%

Abundance and spatial overlap of gobies (Gobiidae) in Lough Hyne, Ireland

Costello

1992

Environ Biol Fish

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“…In an adjacent estuary, Thorman (1982) found an increase in food-niche overlap when the food supply was diminishing in mid summer in a guild of small fishes. He interpreted this as increasing competition for food during the season.…”

Section: Food-niche Overlap and Food Competitionmentioning

confidence: 99%

Food selection and consumption of mobile epibenthic fauna in shallow marine areas

Pihl¹

1985

Mar. Ecol. Prog. Ser.

190

129

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Food selection and consumption of the dominant species among mobile epibenthic fauna was investigated in shallow waters on the Swedish west coast. Newly recruited Pomatoschistus rnicrops, P. minutus, Pleuronectes platessa and Crangon crangon fed initially on meiofauna, whereas young stages of Carcinus maenas preferred 'detritus' (including plant material) and juvenile specimens of macrofauna. Older stages of all 5 species fed on macrofauna. In 1 yr (197?), when low recruitment of some usually abundant macrofaunal species occurred (Moller & Rosenberg 1982,1983, early postlarval stages of C. crangon were eaten mainly by C. maenasand C. crangon. The mobile epibenthic predators are considered opportunistic carnivores mainly feeding on infauna which they select on the basis of relative availability. Total annual food consumption of mobile epibenthic fauna in one area, Gullmarsvik 1978, was calculated to be 26 g AFDW m-2. Food conversion ( P C ) was estimated to be about 0.2 for crustaceans and 0.3 for fishes. The mobile epibenthic fauna consumed 60 to 98 % of the production of the dominant infauna: harpacticoid, ostracods, Corophium volutator, Mya arenaria and Cardjum edule, and is considered as the major biotic regulator of the infauna. In general, food-niche overlap decreased with increasing difference in size between 2 predator species. C. volutator was preferred by all epibenthic predators during most seasons and in Gullmarsvik 1978 contributed on average about 60 % of the food overlap between pairs of predators. M. arenaria and C. edule together made up about 70 % of the food overlap in July and August in this year, and the mobile epibenthic fauna consumed 98, 62 and 92 % of the production of C. volutator, M. arenaria and C. edule, respectively. This strongly suggests that competition between predators exists for these infaunal species, at least during parts of the season.

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Niche Dynamics and Resource Partitioning in a Fish Guild Inhabiting a Shallow Estuary on the Swedish West Coast

Cited by 38 publications

References 10 publications

Vertical distributions and trophic interactions of age-0 Atlantic cod and haddock in mixed and stratified waters of Georges Bank

Vertical distributions and trophic interactions of age-0 Atlantic cod and haddock in mixed and stratified waters of Georges Bank

Abundance and spatial overlap of gobies (Gobiidae) in Lough Hyne, Ireland

Food selection and consumption of mobile epibenthic fauna in shallow marine areas

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