Emergent effects of two rocky intertidal predators on prey: Interaction of crabs and sea-stars may reduce mussel mortality

Sea stars of the Leptasterias species complex are common members of the rocky intertidal community of the temperate and subarctic North American Pacific coast. Variation in 53 morphological characters was studied in 645 Leptasterias spp. collected at 13 intertidal locations from the Aleutian Islands to Oregon. The sea stars were also examined for restriction-site polymorphisms in polymerase chain reaction amplified DNA representing the putative mitochondrial DNA (mtDNA) control region and flanking sequences; these polymorphisms have recently been shown to discriminate among Leptasterias species in the Puget Sound region and southern Alaska. Ten mtDNA haplotypes were identified (designated A–J); five of these (D, E, H, I, and J) had not been reported in earlier surveys and were found at single locations only. Canonical discriminant analysis of morphological variation could partially separate nine of the haplotypes (A–I), but there was some overlap in canonical variable scores between most pairs of haplotypes. Morphologically, the haplotypes formed three major clusters based on canonical variable scores, composed of haplotypes A/C/D, B/E/F/G/H, and I.

Download Full-text

Chemical defense in developmental stages and adult of the sea star Echinaster (Othilia) brasiliensis

PeerJ ◽

10.7717/peerj.11503 ◽

2021 ◽

Vol 9 ◽

pp. e11503

Author(s):

Renato Crespo Pereira ◽

Daniela Bueno Sudatti ◽

Thaise S.G. Moreira ◽

Carlos Renato R. Ventura

Keyword(s):

Chemical Defense ◽

Developmental Stages ◽

Sea Star ◽

Sea Stars ◽

Geographic Ranges ◽

Predator Prey ◽

Larval Stages ◽

Prey Interaction ◽

Specific Predator ◽

Early Developmental

To date, evidence regarding the performance of secondary metabolites from larval stages of sea stars as an anti-predation defense relates only to a few species/specimens from a few geographic ranges. Unfortunately, this hinders a comprehensive global understanding of this inter-specific predator-prey interaction. Here, we present laboratory experimental evidence of chemical defense action in the early developmental stages and adults of the sea star Echinaster (Othilia) brasiliensis from Brazil against sympatric and allopatric invertebrate consumers. Blastulae, early and late brachiolarias of E. (O.) brasiliensis were not consumed by the sympatric and allopatric crabs Mithraculus forceps. Blastulae were also avoided by the sympatric and allopatric individuals of the anemone Anemonia sargassensis, but not the larval stages. Extracts from embryos (blastula) and brachiolarias of E. (O.) brasiliensis from one sampled population (João Fernandes beach) significantly inhibited the consumption by sympatric M. forceps, but not by allopatric crabs and A. sargassensi anemone. In this same site, extracts from adults E. (O.) brasiliensis significantly inhibited the consumption by sympatric and allopatric specimens of the crab in a range of concentrations. Whereas equivalent extract concentrations of E. (O.) brasiliensis from other population (Itaipu beach)inhibited the predation by allopatric M. forceps, while sympatric individuals of this crab avoided the only the higher level tested. Then, early stages and adult specimens of E. (O.) brasiliensis can be chemically defended against consumers, but this action is quite variable, depending on the type (anemone or crab) and the origin of the consumer (sympatric or allopatric).

Download Full-text

Assessing western gull predation on purple sea urchins in the rocky intertidal using optimal foraging theory

Canadian Journal of Zoology ◽

10.1139/z06-203 ◽

2007 ◽

Vol 85 (2) ◽

pp. 221-231 ◽

Cited By ~ 13

Author(s):

C.L. Snellen ◽

P.J. Hodum ◽

E. Fernández-Juricic

Keyword(s):

Optimal Foraging ◽

Sea Urchins ◽

Optimal Foraging Theory ◽

Foraging Theory ◽

Rocky Intertidal ◽

Caloric Content ◽

Sea Stars ◽

Bomb Calorimetry ◽

Intertidal Community ◽

Western Gull

Purple sea urchins ( Strongylocentrotus purpuratus (Stimpson, 1857)) are abundant grazing invertebrates that can have a major impact on the rocky intertidal community. Predators can control the urchin population and indirectly reduce grazing activity. We determined the effects of western gull ( Larus occidentalis Audubon, 1839) predation on purple sea urchins in the rocky intertidal using the framework of optimal foraging theory and taking into account different prey-handling techniques. We recorded the foraging behavior of gulls, measured urchin availability, and estimated prey caloric content with bomb calorimetry. Western gulls selected purple sea urchins significantly more than other prey items (snails (genus Tegula Lesson, 1835), limpets (genus Collisella Dall, 1871), sea stars ( Pisaster giganteus (Stimpson, 1857) and Pisaster ochraceus (Brandt, 1835))). Larger urchins contained relatively more calories. Gulls foraged optimally when pecking by frequently selecting the most profitable size class. However, gulls chose smaller urchins than expected when air-dropping, which could have been influenced by group size and age. Gulls selected smaller purple sea urchins when foraging in larger groups likely owing to the risk of kleptoparasitism. Adults chose larger, and juveniles smaller, urchins when air-dropping, suggesting that juveniles are less experienced in foraging techniques. We estimated that gull predation could affect up to one third of the sea urchin populations locally, which could increase species diversity in the rocky intertidal community.

Download Full-text

Recruitment and abundance of intertidal barnacles and mussels along the Atlantic Canadian coast: pelagic influences and relationships with predator abundance

10.1101/239756 ◽

2017 ◽

Author(s):

Ricardo A. Scrosati ◽

Julius A. Ellrich

Keyword(s):

Large Scale ◽

Atlantic Coast ◽

Seawater Temperature ◽

Rocky Intertidal ◽

Late Winter ◽

In Situ Data ◽

Prey Interaction ◽

Filter Feeders ◽

Benthic Pelagic Coupling ◽

Ocean Boundary

AbstractBenthic species from rocky intertidal systems are irregularly distributed along marine coastlines. Nearshore pelagic conditions often help to explain such variation, but most such studies have been done on eastern ocean boundary coasts. Through a large-scale mensurative study, we investigated possible benthic-pelagic coupling along the Atlantic coast of Nova Scotia, a western ocean boundary coast. We studied the high intertidal zone of nine wave-exposed bedrock locations spanning 415 km of coastline from north to south. At each location in the spring, we measured the recruitment of barnacles and mussels, the two main filter-feeding invertebrates. Recruitment varied irregularly along the coast. Satellite data on coastal phytoplankton and particulate organic carbon (food for intertidal filter-feeders and their pelagic larvae) and in-situ data on seawater temperature explained, to varying degrees, the geographic structure of recruitment. In turn, the summer abundance of both filter-feeders was positively related to their spring recruitment. Ultimately, predator (dogwhelk) abundance was positively related to the recruitment and/or abundance of barnacles and mussels (the main prey of dogwhelks). These results are consistent with bottom-up forcing influencing intertidal community structure on this coast. Sea ice may also influence this predator–prey interaction. Drift ice leaving the Gulf of St. Lawrence in late winter disturbed the northern locations surveyed on the Atlantic coast, making barnacles (owing to their high spring recruitment) the only food source for dogwhelks at such places. Investigating the oceanographic drivers of pelagic food supply and seawater temperature should help to further understand how this large metacommunity is organized.

Download Full-text

Impacts of copper contamination on a rocky intertidal predator-prey interaction

Marine Pollution Bulletin ◽

10.1016/j.marpolbul.2020.111902 ◽

2021 ◽

Vol 162 ◽

pp. 111902

Author(s):

André Pardal ◽

Aline S. Martinez ◽

Ronaldo A. Christofoletti ◽

Simon Karythis ◽

Stuart R. Jenkins

Keyword(s):

Rocky Intertidal ◽

Copper Contamination ◽

Predator Prey ◽

Prey Interaction

Download Full-text

Ocean acidification alters the response of intertidal snails to a key sea star predator

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2016.0890 ◽

2016 ◽

Vol 283 (1833) ◽

pp. 20160890 ◽

Cited By ~ 31

Author(s):

Brittany M. Jellison ◽

Aaron T. Ninokawa ◽

Tessa M. Hill ◽

Eric Sanford ◽

Brian Gaylord

Keyword(s):

Ocean Acidification ◽

Species Interactions ◽

Rocky Intertidal ◽

Sea Star ◽

Predator Prey ◽

Pisaster Ochraceus ◽

Level Shifts ◽

Prey Interaction ◽

Tegula Funebralis ◽

Near Future

Organism-level effects of ocean acidification (OA) are well recognized. Less understood are OA's consequences for ecological species interactions. Here, we examine a behaviourally mediated predator–prey interaction within the rocky intertidal zone of the temperate eastern Pacific Ocean, using it as a model system to explore OA's capacity to impair invertebrate anti-predator behaviours more broadly. Our system involves the iconic sea star predator, Pisaster ochraceus , that elicits flee responses in numerous gastropod prey. We examine, in particular, the capacity for OA-associated reductions in pH to alter flight behaviours of the black turban snail, Tegula funebralis , an often-abundant and well-studied grazer in the system. We assess interactions between these species at 16 discrete levels of pH, quantifying the full functional response of Tegula under present and near-future OA conditions. Results demonstrate the disruption of snail anti-predator behaviours at low pH, with decreases in the time individuals spend in refuge locations. We also show that fluctuations in pH, including those typical of rock pools inhabited by snails, do not materially change outcomes, implying little capacity for episodically benign pH conditions to aid behavioural recovery. Together, these findings suggest a strong potential for OA to induce cascading community-level shifts within this long-studied ecosystem.

Download Full-text

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074768 ◽

1983 ◽

Vol 41 ◽

pp. 194-195

Author(s):

D. F. Blake ◽

L. F. Allard ◽

D. R. Peacor

Keyword(s):

High Resolution ◽

Marine Invertebrates ◽

Sea Urchins ◽

Structural Features ◽

Sea Stars ◽

High Resolution Tem ◽

Relationship Of ◽

The Relationship ◽

Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Download Full-text