Seasonal changes in the diet composition and prey selection of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

Adams, Charles Francis; Pinchuk, Alexei I.; Coyle, Kenneth O.

doi:10.1016/j.fishres.2006.11.032

Cited by 27 publications

(23 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly, Schabetsberger et al (2000) concluded that a strategy of "eat and avoid being eaten" most likely explained the DVM patterns of juvenile pollock at a front in the Bering Sea. It is our conclusion that previously reported feeding patterns (Adams et al 2007), in conjunction with the findings of the present study, can be used to explain the DVM of adult pollock in the northern GOA.…”

Section: Discussionsupporting

confidence: 85%

“…There was no evidence of cannibalism in our study area in 2003 (Adams et al 2007), so adult pollock were not rising to within 20 m of the surface in August to feed on juvenile pollock. Furthermore, pollock selectively fed upon the euphausiid Thysanoessa spinifera in August, while the shrimp Pandalus borealis was the primary component of the diet in November (Adams et al 2007).…”

Section: Discussionmentioning

confidence: 77%

“…Furthermore, pollock selectively fed upon the euphausiid Thysanoessa spinifera in August, while the shrimp Pandalus borealis was the primary component of the diet in November (Adams et al 2007). Euphausiids typically migrate to the surface at night (Brinton et al 2000) while shrimp DVM, if it occurs, is diffuse throughout the water column (Barr 1970).…”

Section: Discussionmentioning

confidence: 99%

“…It is generally thought that there is a reduction in this behavior with age, as adult pollock are increasingly associated with the bottom (e.g., Duffy- Anderson et al 2003). However, recent work in the northern Gulf of Alaska (GOA) has found shoals of adult pollock in the upper 40 m of the water column at night feeding on euphausiids (Adams et al 2007). These findings agree with a report from northern Japan, where adult pollock are sometimes found feeding near the surface at night (Miyashita et al 2004).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Seasonal changes in the diel vertical migration of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

et al. 2009

Self Cite

View full text Add to dashboard Cite

Walleye pollock (Theragra chalcogramma) perform diel vertical migration (DVM) as juveniles, but have an increasing tendency to be associated with the bottom with age. We studied the DVM of a local population of adult pollock in the northern Gulf of Alaska in August and November 2003. There was no relationship between the depth of pollock and the isolume (line of equal light intensity) necessary for visual foraging in August. Pollock passed through the thermocline at this time. In November there was a significant relationship between pollock biomass above/below the 200 m isobath and the isolume necessary for visual foraging. It is hypothesized that in August pollock ignore the isolume and thermocline, simply tracking the movements of their prey (euphausiids) to feed upon them near the surface at night. In November, relatively denser pollock shoals migrate up and down with the isolume necessary for visual foraging to feed on decapods.

show abstract

Section: Discussionsupporting

confidence: 85%

Section: Discussionmentioning

confidence: 77%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Seasonal changes in the diel vertical migration of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

et al. 2009

Self Cite

View full text Add to dashboard Cite

show abstract

“…For this study, we used the Wisconsin Bioenergetics 3.0 model as parameterized for a biologically similar species, walleye pollock Theragra chalcogramma (Tables A.1 and A.2 in the appendix; Hanson et al 1997). The walleye pollock was used as a proxy for Atka mackerel because the two species are semidemersal and overlap considerably in habitat, size range (Barbeaux et al 2008), and diet composition, euphausiids being the most important prey item by weight for both species (Lang and Livingston 1996;Yang 1999;Adams et al 2007). The median age at maturity is 3.6 years for Atka mackerel (McDermott et al.…”

Section: Bioenergetics Modelingmentioning

confidence: 99%

Longitudinal Growth Differences and the Influence of Diet Quality on Atka Mackerel of the Aleutian Islands, Alaska: Using a Bioenergetics Model to Explore Underlying Mechanisms

2010

View full text Add to dashboard Cite

Atka mackerel Pleurogrammus monopterygius make up the single largest biomass of groundfish in the Aleutian Islands, Alaska, and are an important component of this marine ecosystem. Atka mackerel show a significant decrease in size from east to west. We compared fish from two study areas reflecting this size cline: Seguam Pass in the eastern Aleutians and Amchitka Island in the western Aleutians. At any given age, the Atka mackerel at the former location are larger than those at the latter (e.g., 5‐year‐old fish average 732 g and 39 cm fork length at Seguam Pass but only 575 g and 36 cm at Amchitka Island). Our objectives were to determine the mechanisms underlying the observed differences in growth, such as prey availability, prey quality, and thermal experience. We used a bioenergetics model to examine the effects of diet and temperature on growth. The model estimates of consumption fell within the range of those observed for Atka mackerel, suggesting that the model was an appropriate tool for exploring these effects. The results obtained with the model suggest that prey quality is the main factor in the observed size differences. At Seguam Pass Atka mackerel ate a more energetically rich diet consisting of euphausiids and fish, whereas at Amchitka Island copepods dominated the diet and there was little to no fish consumption. The model results also suggest that thermal experience contributed less to the observed differences in growth than did the composition of the diet. Understanding the mechanisms underlying the growth of Atka mackerel will improve predictions of biomass and yield within the framework of a dynamic ecosystem and a changing climate.

show abstract

Mixing it up in Alaska: Habitat use of adult female Steller sea lions reveals a variety of foraging strategies

et al. 2020

View full text Add to dashboard Cite

From 2010 to 2015, satellite transmitters were deployed on 16 adult female Steller sea lions (AFSSLs; Eumetopias jubatus) in three regions of Alaska because there is limited information regarding the habitat use of this age class during winter and populations have yet to recover in western Alaska. Two approaches were used to assess how static (distance to shore, sea lion site, and continental shelf break, presence on/off the continental shelf, and bathymetric depth and slope), dynamic (proportion of daylight, fraction of lunar illumination, chlorophyll‐a, wind speed, sea surface height, eddy kinetic energy, and sea surface temperature), and other (region, distinct population segment, and season) covariates affected the habitat use of AFSSLs. Multimodel inference was first used to examine diving behaviors (mean and maximum dive depths, dive frequency) with respect to covariates using linear mixed‐effects models, whereas single model inference was used to examine kernel density estimates (KDEs) of individual monthly utilization distributions (n = 74) in western Alaska with respect to environmental covariates using generalized additive models. Additionally, weighted coefficients from these models were examined for the population as a whole, within each individual, between regions, and across monthly scales. Comparisons of foraging behaviors of AFSSLs over time and space revealed pronounced individual variability within overall broader patterns. Response variables of most models were related to various combinations of predictor variables, but distance to shore was the most influential variable across all models. As expected with a non‐migratory central place forager, frequency of diving and KDEs were greater on the shelf and near shore, though maximum dive depths increased with distance to shore. Interaction effects (proportion of day light*on/off shelf) observed for mean dive depths suggested AFSSLs were feeding on benthic species when in shelf waters near shore, whereas they were likely feeding on vertically migrating prey species while off‐shelf. Relationships regarding diving behaviors and KDEs of AFSSLs relative to dynamic oceanographic variables were not as prominent as those observed for static environmental variables, though some signals were apparent at different scales. Overall, static environmental features likely provided more consistent sources of habitat for prey resources, thereby making them more predictable for AFSSLs.

show abstract

Seasonal changes in the diet composition and prey selection of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

Cited by 27 publications

References 41 publications

Seasonal changes in the diel vertical migration of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

Seasonal changes in the diel vertical migration of walleye pollock (Theragra chalcogramma) in the northern Gulf of Alaska

Longitudinal Growth Differences and the Influence of Diet Quality on Atka Mackerel of the Aleutian Islands, Alaska: Using a Bioenergetics Model to Explore Underlying Mechanisms

Mixing it up in Alaska: Habitat use of adult female Steller sea lions reveals a variety of foraging strategies

Contact Info

Product

Resources

About