Effects of Abiotic Disturbance on Coexistence of Predator-Prey Fish Species

Abstract. There is increasing demand for information on predator-prey interactions in the ocean as a result of legislative commitments aimed at achieving sustainable exploitation. However, comprehensive datasets are lacking for many fish species and this has hampered development of multispecies fisheries models and the formulation of effective food-web indicators. This work describes a new compilation of stomach content data for five pelagic fish species (herring, blue whiting, mackerel, albacore and bluefin tuna) sampled across the northeast Atlantic and submitted to the PANGAEA open-access data portal (www.pangaea.de). We provide detailed descriptions of sample origin and of the corresponding database structures. We describe the main results in terms of diet composition and predator–prey relationships. The feeding preferences of small pelagic fish (herring, blue whiting, mackerel) were sampled over a very broad geographic area within the North Atlantic basin, from Greenland in the west, to the Lofoten Islands in the east and from the Bay of Biscay northwards to the Arctic. This analysis revealed significant differences in the prey items selected in different parts of the region at different times of year. Tunas (albacore and bluefin) were sampled in the Bay of Biscay and Celtic Sea. Dominant prey items for these species varied by location, year and season. This data compilation exercise represents one of the largest and most wide-ranging ever attempted for pelagic fish in the north Atlantic. The earliest data included in the database were collected in 1864, whereas the most recent were collected in 2012.Datasets are available at doi:10.1594/PANGAEA.820041 and doi:10.1594/PANGAEA.826992.

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Predator–prey interactions influenced by a dynamic river plume

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2016-0302 ◽

2017 ◽

Vol 74 (9) ◽

pp. 1375-1390 ◽

Cited By ~ 6

Author(s):

Elizabeth M. Phillips ◽

John K. Horne ◽

Jeannette E. Zamon

Keyword(s):

Columbia River ◽

Water Clarity ◽

Center Of Gravity ◽

River Plume ◽

Prey Fish ◽

Predator Prey ◽

Marine Predator ◽

Global Indices ◽

Common Murre ◽

Columbia River Plume

Marine predator–prey interactions are often influenced by oceanographic processes that aggregate prey. We examined density distributions of seabirds and prey fish associated with the Columbia River plume to determine whether variation in plume size (i.e., volume or surface area) or location influences predator–prey interactions. Common murre (Uria aalge), sooty shearwater (Ardenna grisea), and forage fish, including northern anchovy (Engraulis mordax) and juvenile salmon (Oncorhynchus spp.), occurred disproportionately in plume waters relative to adjacent marine waters. Water clarity, an indicator of plume-influenced waters, was a significant predictor of seabird and prey densities throughout the survey area. Murres occurred within 20 km of the plume center of gravity, whereas shearwaters occurred ∼100 km north of the plume center of gravity, concurrent with the highest densities of prey fish. Global indices of collocation were relatively low between murres and prey compared with the high values between shearwaters and prey. Seabird densities were negatively correlated with plume size, suggesting that seabirds concentrate in the plume to maximize foraging effort. We conclude that variation in Columbia River plume size and location influences predator distributions, which increases predation pressure on prey, including threatened salmonid species.

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Body size, not other morphological traits, characterizes cascading effects in fish assemblage composition following commercial netting

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-183 ◽

2005 ◽

Vol 62 (12) ◽

pp. 2802-2810 ◽

Cited By ~ 22

Author(s):

C A Layman ◽

R B Langerhans ◽

K O Winemiller

Keyword(s):

Morphological Traits ◽

Fish Assemblages ◽

Human Impacts ◽

Morphological Characteristics ◽

Prey Fish ◽

Geometric Morphometric ◽

Complex Species ◽

Predator Prey ◽

Assemblage Composition ◽

Cascading Effects

Traits used to group species and generalize predatorprey interactions can aid in constructing models to assess human impacts on food webs, especially in complex, species-rich systems. Commercial netting has reduced populations of large-bodied piscivores in some lagoons of a Venezuelan floodplain river, and cascading effects result in distinct prey fish communities in netted and unnetted lagoons. In 2002 and 2003, we sampled assemblages of prey fishes in netted and unnetted lagoons and tested whether fish size and (or) other morphological characteristics were associated with differences in assemblage composition. In both years, prey fish assemblages in netted lagoons were dominated numerically by larger species. We used geometric morphometric methods to test for a relationship between species morphological characteristics and found that neither overall morphological ordination nor specific morphological traits could be used to distinguish among assemblages. Thus, size was the only variable that was useful in explaining differences in assemblage composition. Even in this species-rich river with a complex food web, size-structured predatorprey interactions apparently influence community-level patterns and can be used to characterize human impacts.

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