Topic
Whelk
About: Whelk is a research topic. Over the lifetime, 291 publications have been published within this topic receiving 5468 citations.
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Papers
TL;DR: The results support the idea that in keystone—dominated systems, species other than the keystone species have only minor, if any, effects on the rest of the community, and thus might be cited by some as redundant species, and indicate that, after the loss of a keystones species, previously redundant species can partially compensate for the reduced predation and adopt a major role in the altered system.
Abstract: The application of basic ecological concepts to fields of conservation biology and applied environmental sciences is a healthy sign, but before these concepts are widely used, ecology must provide operational definitions and quantifiable methods. Keystone species and interaction strength are concepts with deep practical and theoretical implications. We studied the strength of predation on mussels (Mytilus trossulus) by the keystone seastar Pisaster ochraceus and the whelks Nucella emarginata and N. canaliculata under different environmental conditions in the Oregon intertidal zone. We attempted to determine: (1) the sensitivity of keystone predation to the presence of other predators in the system; (2) the role of other predators in the presence and absence of a keystone species; and (3) the per capita and population—level variability in interaction strengths of strong (keystone) vs. weak interactors. Predation intensity on mussels was measured by recording the survival of mussels transplanted to areas from which seastars, whelks, or both, had been either manually removed or left undisturbed at natural densities. Whelk experimental units were nested within those for the seastar treatment to account for the much larger body size and greater mobility of seastars. Each combination of seastar and whelk treatment was replicated four times in both wave—exposed and wave—protected habitats of two sites that differed in predator densities, primary productivity, and recruitment and growth rates of prey species. Predation intensity by the keystone predator was strong under all site $\times$ wave exposure combinations, and was unaffected by the presence of whelks. Whelks, in contrast, had ecologically important effects on mussel survival in the absence, but not in the presence, of the keystone predator. Population (total) interaction strength between seastars and mussels was 2—10 times stronger than that between whelks and mussels across sites and wave exposures. Per capita interaction strength of seastars was two to three orders of magnitude larger than that of whelks. However, per capita effects of seastars were more variable between sites and wave exposures, probably because simple density values grossly underestimate the ability of mobile predators to localize prey. Such interactive effects and variability in interaction strengths between keystone and weak predators may characterize all keystone predator—dominated systems, but data currently are insufficient to test this proposition. Negative effects of seastars on whelk density were observed <4 mo following initiation of Pisaster removals. Seastars also had a negative effect on whelk sizes, which took longer to appear, after 6 mo of continuous Pisaster removal. Negative effects of seastars on whelks appeared to be stronger in places with higher densities of predators, partially explaining the reduced predation intensity of whelks observed in the presence of seastars. Our results support the idea that in keystone—dominated systems, species other than the keystone species have only minor, if any, effects on the rest of the community, and thus might be cited by some as redundant species. However, our results also indicate that, after the loss of a keystone species, previously redundant species can partially compensate for the reduced predation and adopt a major role in the altered system. Such responses are potentially an important force in stabilizing communities. Further, such possible compensatory capabilities of alternative consumers suggests that, at least for predators, the term redundant species conveys an inaccurate image of the potential importance of weak interactors and should be abandoned.
231 citations
TL;DR: A systematic approach is required to address the complex issue of bottom-trawl disturbances, starting with the identification of chronic and acute impacts, followed by focused investigations of ecological implications and, ultimately, cost-benefit analyses to evaluate specific resource-management options.
Abstract: The eastern Bering Sea has experienced rapid and intensive development of commercial trawl fisheries. Because of good record keeping and the relatively brief history of fishing it is possible to reconstruct the spatial and temporal patterns of exploitation. Previously unfished (UF) areas can be identified and directly compared with heavily fished (HF) areas to investigate long-term consequences for the benthos. Using this approach, macrofauna populations in a shallow (48 m average) soft-bottom area were studied during 1996. Samples of 92 taxa (reduced for analysis) were collected at 84-1 nm 2 sites straddling a closed-area boundary. Multi- and univariate statistical tests and raw patterns in the data support the following generalizations: (1) sedentary macrofauna (e.g., anemones, soft corals, sponges, whelk eggs, bryozoans, ascidians), neptunid whelks, and empty shells were more abundant in the UF area; (2) mixed responses were observed within motile groups (e.g. crabs, sea stars, whelks) and infaunal bivalves, suggesting the importance of life history characteristics, such as habitat requirements and feeding mode; and (3) overall diversity and niche breadth of sedentary taxa were greater in the UF area. A systematic approach is required to address the complex issue of bottom-trawl disturbances. This begins with the identification of chronic and acute impacts, followed by focused investigations of ecological implications and, ultimately, cost-benefit analyses to evaluate specific resource-management options.
148 citations
TL;DR: There may be a trade-off between shell thickness and linear shell growth and a potential delay in attaining a size refuge from predation.
Abstract: Predators such as crabs, whelks, and sea stars attack their bivalve prey in different ways, and predator-induced defenses are an important means of protection. The degree to which induced defenses are specific to different predators, however, remains largely unknown. In laboratory experiments (June to August 1998), we raised mussels (Mytilus edulis L.) in the presence of a drilling predator [the whelk Nucella lapillus (L.)] or a crushing predator [the crab Carcinus maenas (L.)] to determine whether induced changes in prey shell thickness, size, or shape occurred and whether changes were predator-specific. Over a 2 month period, juvenile mussels were exposed to waterborne cues from actively feeding crabs or whelks. Mussels produced thicker shell lips in response to both predators relative to control mussels raised in their absence, and the difference was significantly greater in response to whelks than to crabs. Mussels exposed to whelks showed significantly smaller increases in shell length and width and total wet weight than did mussels exposed to crabs. Thus, there may be a trade-off between shell thickness and linear shell growth and a potential delay in attaining a size refuge from predation.
128 citations
TL;DR: It is concluded that traces of mobile animals can influence the settlement of sessile animals and the avoidance response of the barnacle to the traces of limpets and macroalgae offers an alternative explanation to patterns often attributed to biological disturbance.
125 citations
TL;DR: Results suggests that restoration efforts should consider 3-dimensional benthic topography similar to established oyster reefs to provide hydrodynamic conditions and settlement surfaces that promote larval recruitment, prevent burial by sediment, and provide refuge from predation.
Abstract: Restoration efforts to enhance Crassostrea virginica oyster populations along the Vir- ginia, USA, coastline focus on creating benthic habitat suitable for larval recruitment, survival, and growth. To determine how benthic flow processes affect larval recruitment, velocity and tur- bulence we collected data over multiple intertidal benthic surfaces including a mud bed, a C. vir- ginica oyster reef, and 2 restoration sites comprised of deposited C. virginica oyster shell or the relatively larger Busycotypus canaliculatus whelk shell. Mean estimates of the drag coefficient, CD, used as a measure of hydrodynamic roughness over the C. virginica reef were found to be 2 times greater than over the restoration sites and 5 times greater than over the mud bed. Enhanced fluid shear increased both peak Reynolds stresses and vertical momentum transport above the reef, but within the interstitial areas between individual oysters, velocities and turbulence were reduced. Larval settlement plates of varying triangular-shaped benthic roughness were used to mimic the natural topographic variability found along oyster reefs. The greatest larval recruitment occurred along interstitial regions between high-roughness topography, where shear stresses, which act to dislodge larvae, were found to be up to 20 times smaller than along exposed surfaces. Greater recruitment was also found on the more hydrodynamically rough whelk shell compared to the oyster shell restoration site. Results suggests that restoration efforts should consider creat- ing 3-dimensional benthic topography similar to established oyster reefs to provide hydrodynamic conditions and settlement surfaces that promote larval recruitment, prevent burial by sediment, and provide refuge from predation.
123 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 11 |
| 2024 | 12 |
| 2023 | 8 |
| 2022 | 33 |
| 2021 | 10 |
| 2020 | 7 |