Temporal variation in abundance of the egg predator Carcinonemertes epialti (Nemertea) and its effect on egg mortality of its host, the shore crab, Hemigrapsus oregonensis

Hydrobiologia ◽  
1988 ◽  
Vol 156 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Jeffrey D. Shields ◽  
Armand M. Kuris
Keyword(s):  
Temporal Variation ◽  
Shore Crab ◽  
Egg Mortality ◽  
Egg Predator ◽  
Hemigrapsus Oregonensis

scholarly journals Long-term change in the parasite burden of shore crabs ( Hemigrapsus oregonensis and Hemigrapsus nudus ) on the northwestern Pacific coast of North America

2021 ◽  
Vol 288 (1945) ◽  
pp. 20203036
Author(s):  
Jessica Quinn ◽  
Sarah Lee ◽  
Duncan Greeley ◽  
Alyssa Gehman ◽  
Armand M. Kuris ◽  
...  
Keyword(s):  
Parasite Burden ◽  
Shore Crab ◽  
Northwestern Pacific ◽  
Intermediate Hosts ◽  
Term Change ◽  
Shore Crabs ◽  
Living Species ◽  
Hemigrapsus Oregonensis ◽  
Over Time

The abundances of free-living species have changed dramatically in recent decades, but little is known about change in the abundance of parasitic species. We investigated whether populations of several parasites have shifted over time in two shore crab hosts, Hemigrapsus oregonensis and Hemigrapsus nudus, by comparing the prevalence and abundance of three parasite taxa in a historical dataset (1969–1970) to contemporary parasite abundance (2018–2020) for hosts collected from 11 intertidal sites located from Oregon, USA, to British Columbia, Canada. Our data suggest that the abundance of the parasitic isopod Portunion conformis has varied around a stable mean for the past 50 years. No change over time was observed for larval acanthocephalans. However, larval microphallid trematodes increased in prevalence over time among H. oregonensis hosts, from a mean of 8.4–61.8% between the historical and contemporary time points. The substantial increase in the prevalence of larval microphallid trematodes could be owing to increased abundances of their bird final hosts, increased production of parasite infective stages by snail intermediate hosts or both. Our study highlights the variability among parasite species in their temporal trajectories of change.

Infestation by Brood Symbionts and Their Impact on Egg Mortality of the Red King Crab, Paralithodes camtschatica, in Alaska: Geographic and Temporal Variation

1991 ◽  
Vol 48 (4) ◽  
pp. 559-568 ◽  
Author(s):  
Armand M. Kuris ◽  
S. Forrest Blau ◽  
A. J. Paul ◽  
Jeffrey D. Shields ◽  
Daniel E. Wickham
Keyword(s):  
Life History ◽  
Life Cycle ◽  
Temporal Variation ◽  
Seasonal Pattern ◽  
Red King Crab ◽  
King Crab ◽  
Egg Masses ◽  
Egg Mortality ◽  
Paralithodes Camtschatica

Egg masses of 772 red king crab, Paralithodes camtschatica, were sampled to determine the prevalence, intensity, and patterns of cooccurrence of brood symbionts from 28 Alaskan localities. Carcinonemertes regicides and three other undescribed nemertean egg predators were recovered from many localities, as were an undescribed turbellarian and an amphipod, Ischyrocerus sp. A widespread outbreak of nemerteans occurred in the 1983–84 and 1984–85 red king crab brooding seasons. At some locations, nearly all of the eggs were consumed in the 1983–84 brood season. Feeding of C. regicides on eggs was documented in vitro and these worms caused substantial egg mortality at many locations. The amphipod was also an egg predator and may have had a significant impact at three locations. The turbellarian did not kill eggs. From the seasonal pattern of C. regicides infestation at Kachemak Bay, we postulate an abbreviated life cycle and autoinfection for C. regicides. Such life history features may have contributed to the peak intensities observed late in the 1983–84 and 1984–85 brooding seasons. At some localities, heavy brood mortality may reduce or eliminate recruitment of some year classes to the fishery.

Brood Mortality and Egg Predation by the Nemertean, Carcinonemertes epialti, on the Yellow Rock Crab, Cancer anthonyi, in Southern California

1990 ◽  
Vol 47 (7) ◽  
pp. 1275-1281 ◽  
Author(s):  
Jeffrey D. Shields ◽  
Robert K. Okazaki ◽  
Armand M. Kuris
Keyword(s):  
Host Species ◽  
Southern California ◽  
Egg Mass ◽  
Minimal Impact ◽  
Egg Mortality ◽  
High Prevalence ◽  
Important Host ◽  
Rock Crab ◽  
Highly Correlated ◽  
Hemigrapsus Oregonensis

Carcinonemertes epialti had a minimal impact on the egg mortality of a lightly infested population of a commercially important crab host, Cancer anthonyi. The nemertean had a high prevalence (> 97%) but was found at low intensities (mean intensity = 86.5 worms/pleopod, mean density = 0.3 worms/1000 eggs). Egg mortality varied from 0.0–30.5%, and was highly correlated with both worm intensity, and the timing of crab embryogenesis (mean mortality = 5.7%). Separate sites within the pleopod experienced different causal mechanisms of mortality. Mortality at the base of the pleopod was correlated with the presence, abundance, and immigration of C. epialti. Mortality at the tip of the pleopod was less correlated with worm abundance and was most likely a result of abrasion to the eggs or egg mass. Infestations of C. epialti varied between seasons and between host species. The worm was more abundant on host species that bred year-round (Cancer anthonyi and Hemigrapsus oregonensis); hence, infestation dynamics varied markedly between host species. In southern California, Cancer anthonyi was virtually always infested with C. epialti and is the most important host for the worm in this area.

scholarly journals A whiter shade of male: Color background matching as a function of size and sex in the yellow shore crab Hemigrapsus oregonensis (Dana, 1851)

2015 ◽  
Vol 61 (4) ◽  
pp. 729-738 ◽  
Author(s):  
Gregory C. Jensen ◽  
Michael S. Egnotovich
Keyword(s):  
Carapace Width ◽  
Shore Crab ◽  
Differential Mortality ◽  
Striking Difference ◽  
White Background ◽  
Female Size ◽  
White Males ◽  
Color Background ◽  
Hemigrapsus Oregonensis ◽  
Pure White

Abstract Juveniles of the shore crab Hemigrapsus oregonensis are highly variable in color, ranging from the typical yellowishgreen of adults to pure white and myriad patterns of white mottling and other disruptive markings, but large individuals with white coloration appear to be very rare. Using image analysis to quantify the relative “whiteness” of beaches, we sampled crabs from nine locations in Washington State that varied widely in their amount of shell fragments and other light-colored material. The total proportion of white individuals in the different locations was strongly correlated to the proportion of white material on the beaches, but there was a striking difference between sexes. Although white specimens of both sexes declined significantly at sizes above 10 mm carapace width, white females generally persisted throughout the entire female size range on lighter-colored beaches while white males larger than 10 mm were virtually absent from all of the sampled populations. Pure white males held on dark backgrounds in captivity remained white, as they lack the dark chromatophores in their hypodermis needed to change color; off-white males became darker and in some cases lightened up again when transferred back to a white background. Behavioral differences between the sexes may result in differential mortality of white individuals by visual predators.

scholarly journals Ontogenetic changes in the olfactory antennules of the shore crab, Hemigrapsus oregonensis , maintain sniffing function during growth

2015 ◽  
Vol 12 (102) ◽  
pp. 20141077 ◽  
Author(s):  
Lindsay D. Waldrop ◽  
Miranda Hann ◽  
Amy K. Henry ◽  
Agnes Kim ◽  
Ayesha Punjabi ◽  
...  
Keyword(s):  
Particle Image ◽  
Relative Size ◽  
Physical Models ◽  
Shore Crab ◽  
Ontogenetic Changes ◽  
Return Stroke ◽  
Critical Range ◽  
Image Velocimetry ◽  
Flow Through ◽  
Hemigrapsus Oregonensis

Malacostracan crustaceans capture odours using arrays of chemosensory hairs (aesthetascs) on antennules. Lobsters and stomatopods have sparse aesthetascs on long antennules that flick with a rapid downstroke when water flows between the aesthetascs and a slow return stroke when water is trapped within the array (sniffing). Changes in velocity only cause big differences in flow through an array in a critical range of hair size, spacing and speed. Crabs have short antennules bearing dense arrays of flexible aesthetascs that splay apart during downstroke and clump together during return. Can crabs sniff, and when during ontogeny are they big enough to sniff? Antennules of Hemigrapsus oregonensis representing an ontogenetic series from small juveniles to adults were used to design dynamically scaled physical models. Particle image velocimetry quantified fluid flow through each array and showed that even very small crabs capture a new water sample in their arrays during the downstroke and retain that sample during return stroke. Comparison with isometrically scaled antennules suggests that reduction in aesthetasc flexural stiffness during ontogeny, in addition to increase in aesthetasc number and decrease in relative size, maintain sniffing as crabs grow. Sniffing performance of intermediate-sized juveniles was worse than for smaller and larger crabs.

scholarly journals Spatio-temporal variation of the population structure and density of the shore crab Pachygrapsus gracilis (Grapsidae) in an estuary on the Brazilian Amazon coast

Nauplius ◽  
2021 ◽  
Vol 29 ◽  
Author(s):  
Priscila Sousa Vilela da Nóbrega ◽  
Miani Corrêa Quaresma ◽  
Francielly Alcântara de Lima ◽  
Jussara Moretto Martinelli-Lemos
Keyword(s):  
Population Structure ◽  
Temporal Variation ◽  
Brazilian Amazon ◽  
Shore Crab ◽  
Spatio Temporal
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