Byssus Research Articles

Effect of emersion on soft-shell clam,Mya arenariaand the mussel,Mytilus edulisseeds in relation to development of vitality indices

Blue mussels (Mytilus edulis ) and soft-shell clams (Mya arenaria ) are both aquaculture species in east coast of Canada and US shellfish farmers take advantage of the byssal threads production of mussels for suspension culture and the burrowing behaviour of soft-shell clams for enhancement practices. It is important that these animals attach and burrow efficiently to minimize losses during rearing. The aim of this work was to study two potential vitality indices on mussels (23.6 ± 0.1 mm) and clams (22.6 ± 0.1 mm) seeds following various periods of emersion: attachment strength of Mytilus edulis and burrowing ability of Mya arenaria. The effect of emersion on energy content (proteins, lipids, glycogen) was also examined. We observed no significant decrease in the attachment strength of mussels after air exposure for 78 h or in the burrowing efficiency of soft-shell clams after 54 h. Air exposure had no effect on different lipid classes, proteins, or glycogen content in either mussel or clam tissues. The stressful emersion event induced in our study may not have been high enough to induce detectable behavioural responses. This can be explained by the bivalves’ ability to adapt their metabolism to minimize activity during air exposure. In doing so, they do not consume their energy reserves, which are then still available when specimens are reimmersed. Thus mussels are able to efficiently produce byssal threads and clams to burrow into sediments as soon as they are back in the water.

Structural and functional features of a collagen-binding matrix protein from the mussel byssus

Blue mussels adhere to surfaces by the byssus, a holdfast structure composed of individual threads representing a collagen fibre reinforced composite. Here, we present the crystal structure and function of one of its matrix proteins, the proximal thread matrix protein 1, which is present in the proximal section of the byssus. The structure reveals two von Willebrand factor type A domains linked by a two-β-stranded linker yielding a novel structural arrangement. In vitro, the protein binds heterologous collagens with high affinity and affects collagen assembly, morphology and arrangement of its fibrils. By providing charged surface clusters as well as insufficiently coordinated metal ions, the proximal thread matrix protein 1 might interconnect other byssal proteins and thereby contribute to the integrity of the byssal threads in vivo. Moreover, the protein could be used for adjusting the mechanical properties of collagen materials, a function likely important in the natural byssus.

Impact of open sea habitat on byssus attachment of suspension-cultured blue mussels (Mytilus edulis)

Offshore and open sea suspension-culture of mussels is largely in development but, in this particular environment, sleeved mussels are submitted to high-energy oceanographic conditions which could increase fall-offs. In this study, we compared the performance of open sea mussel culture to that of culture in a lagoon environment. Byssus attachment strength, condition index, mechanical properties of individual byssal threads, metal content of the filaments for mussels from both the open sea and the semi-closed lagoon sites were monitored as well as the environmental characteristics of these sites. The spawning event occurred approximately one month earlier for mussels in the open sea than in the lagoon, probably due to a difference in temperature and food availability. The attachment strength of the mussels was weaker in the open sea, even if individual threads were bigger and stronger than in the lagoon. This lower attachment strength seems related to a lower production of byssal threads. • The spawning occurred one month earlier in the open-sea than in the lagoon. • The attachment strength of the mussels was weaker in the open-sea. • Individual threads were bigger and stronger in the open-sea. • The higher thread resistance would be mainly related to the Ca concentration.

The origin and formation of hair on external valve surfaces of the tropical marine mussel Modiolus traillii (Reeve, 1857)

Direct observations using digital videography in an aquarium showed that hairs on the valve surfaces of Modiolus traillii are not periostracal in origin, as often assumed for similar features in other mussels, but are secreted and planted individually by the foot, so they are correctly termed ‘byssal hairs’. Deposition of byssal hair occurred most frequently just after dark, and the time taken to form a strand of serrated hair varied between slightly more than 1 min to almost 10 min, with a mean time of 4.4 min. We observed one individual deposit a total of 11 hairs in 3.5 h. The formation of some 25 hairs were successfully observed on video for six individuals, and about 3,000 individual hairs from 12 mussels were measured in relation to their position, size and density. While hairs varied considerably in length and width, they are consistently flattened, with one edge bearing serrations and the other edge being smooth. Long hair required more time to form compared with shorter hair, and longer hair was deposited farther away from the byssal gape towards the posterior end of the valves. However, a higher density of short hair was laid around the byssal gape. Smaller mussels tended to have an overall higher density of hair compared with larger individuals. There was no discernible pattern in the order in which long and short hairs were secreted on the periostracal surfaces of either valve. Byssal hair microstructure was generally consistent with the distal region of byssal threads, having a tough but thin outer cortex surrounding a ‘spongy’ honeycomb matrix.

A New Species ofCyamiocardiumSoot-Ryen, 1951 from Shallow Waters off Brazil, with a Discussion on the Anatomical Characters of the Cyamiidae (Bivalvia: Cyamioidea)

Cyamiocardium domaneschii n. sp. is described from shallow waters off the Southeastern coast of Brazil. An anatomical study provides comparisons with other Cyamioidea. It has a small shell (up to 3.1 mm in length), valves with a rounded contour, external radial sculpture, a distinct large prodissoconch, and hinge structure characteristics of the genus Cyamiocardium Soot-Ryen, 1951. Three well-defined pallial openings are present; tentacles border the anteriormost part of the pedal opening and the inhalant and exhalant apertures. The inner demibranchs are larger than the outers, do not have interlamellar junctions, and form a spacious brooding chamber. It is dioecious and developing oocytes are covered by a thin follicular tissue, which persists as a covering of each brooded young. Offspring are retained up to the juvenile stage, and are attached to the gill filaments by a long stalk. The foot has a narrow, grooved ventral sole; no byssus threads were observed. An active burrowing or crawling behavior is suggested for C. domaneschii n. sp., as there are well developed statocysts. This finding of a cyamiid from Brazil represents the extension of the geographical distribution of this family further north in the southwestern Atlantic Ocean. This study also reveals that some anatomical characters are variable in the genus Cyamiocardium: in C. denticulatum (Smith, 1907), there are only two pallial openings and its foot does not have a ventral sole. The attachment of young to the gills are not related to nourishment, and here for C. domaneschii n. sp. it is suggested that the stalk is only used as a “safety belt”, preventing embryos and juveniles to be released before the end of their development. More studies remain to be done on the anatomy of cyamioideans, particularly on living specimens; we paid attention to common characters used for discussions on the taxonomy and biology of these bivalves.

Free-living nematodes of the genus Halomonhystera (Monhysteridae) from the Southwest Pacific region and Ross Sea

Three Halomonhystera species are described from the Southwest Pacific region and Ross Sea. Halomonhystera tangaroa sp. nov. is described from the byssus threads of hydrothermal vent mussels (Gigantidas gladius) at the summit of Tangaroa Seamount on the southern Kermadec Arc, Southwest Pacific. Halomonhystera tangaroa sp. nov. is characterized by the presence of four relatively long cephalic setae (one-quarter to one-third of the labial diameter), deep and narrow buccal cavity, gubernaculum with dorsal apophyses, males with three pairs of subventral papillae near tail tip, and females with vulva situated at 85–86% of body length from anterior. Halomonhystera spp. A and B (from the New Zealand coast and Ross Sea shelf, respectively) are morphologically distinct from each other, but are both consistent with previous descriptions of Halomonhystera disjuncta (Bastian, 1865). Molecular studies have shown that H. disjuncta is in fact a species complex, and, because the original description of H. disjuncta provides only limited morphological data, and the subsequent re-description of the species encompasses a wide range of morphologies, it is not possible to determine to which lineage(s) these descriptions may be pertaining. Determining the identities of Halomonhystera spp. A and B will require comparisons of morphological and molecular characters with H. disjuncta specimens from the type locality.http://zoobank.org/urn:lsid:zoobank.org:pub:029E6773-5E37-4D69-A85E-D4FB663BC059

Heavy Metal Concentration from Biologically Important Edible Species of Bivalves (Perna viridis and Modiolus metcalfei) from Vellar Estuary, South East Coast of India

Commonly mollusks are filter feeding in habits so while feeding from the mud the unwanted chemicals and metals are accumulate in the organs like gills, foot and mantle. These edible bivalves can better be used for biomonitoring in case of the food safety at regularly used by the local fisherman community. So it is very important necessity to study about edible mollusks and with the aim of the present study is carried. Assessment of heavy metal such as Cd, Cr, Cu, Pb and Zn accumulation of seven different body parts viz, Foot, Mantle, Gonad, Adductor muscle, Byssal thread, Gills and shell from two different edible bivalve species of Perna viridis and Modiolus metcalfei were carried briefly. Among all the metals, Zn was higher and Cd was lower concentration were observed from two different bivalve and their values varied with respect to different body parts. The accumulation of these five heavy metals ranged as Cd (0.022-0.091 μg/g), Cr (0.147-0.447 μg/g) Cu (0.126-0.356 μg/g), Pb (0.145-1.57 μg/g) and Zn (0.964–8.607 μg/g) for P.viridis and M. metcalfei ranged as Cd (0.013-0.095 μg/g), Cr (0.092-0.495 μg/g) Cu (0.063-0.367 μg/g), Pb (0.528-1.263 μg/g) and Zn (2.172-11.113 μg/g). Cluster analysis (Bray-Curtis Similarity) was used for making the similarity percentage between different body parts of edible bivalves and comparison also done with sediment metal concentration. In general, all heavy metals are less than the permissible level according to WHO/EPA except Cr and Pb from both bivalves.

Morphological–behavioral adaptations of two benthic invertebrate species to face strong bed hydrodynamic forces in a large South-American river

This scientific communication describes and discusses morphological–behavioral adaptations to flow of two benthic invertebrate species to survive in highly turbulent habitats of the large Paraguay River (Argentina – Paraguay). It is based on field and laboratory observations under microscope made during the performance of usual researches. In this sense, we found that Djalmabatista sp. 1 (Chironomidae, Tanypodinae) ballasts its body by ingestion of fine sediment grains which storage into a dorsal bulge, herein called “dorsal bag”. This specie would have the ability to take or release these grains according to the surrounding hydrodynamic conditions. Otherwise, the juvenile stage of Limnoperna fortunei (Bivalvia, Mytilidae) also ballasts its body but attaching sand grains through the byssal threads.

Rapid self-healing and triple stimuli responsiveness of a supramolecular polymer gel based on boron–catechol interactions in a novel water-soluble mussel-inspired copolymer

Marine and freshwater mussels secrete proteinaceous adhesive materials for adherence to the substrates upon which they reside. It is well known that 3,4-dihydroxyphenylalanine (DOPA) is the key to understanding these mussel adhesive proteins (MAPs). In order to gain a better understanding of their complex formation and quick recovery upon rupturing, novel water soluble copolymers of N-isopropylacrylamide and dopamine methacrylate were synthesized in such a way that they have 1, 2.5, and 5 mole percent dopamine monomer with respect to the NIPAM monomer on average. The statistical distribution of DOPA-functionalities along the chain makes the material a close synthetic equivalent of the byssal thread proteins of mytili. At acidic pH, the aqueous copolymer solution behaves like an unentangled copolymer solution, but at basic pH, these catechol functionalities form a dicomplex with H3BO3, thereby crosslinking two chains, proven by 11B-NMR and gelation. The polymer solution is thermosensitive with a pH-dependent lower critical solution temperature (LCST) between 21 and 33 °C, depending on the DOPA-content. If 2 or more functionalities per chain are present, a gel is formed that is self-healing with very quick recovery from sustained damage. The moduli of the gels depend on the concentration of functionalities. Hence, triple stimuli responsive copolymers were obtained.

The role of topology and thermal backbone fluctuations on sacrificial bond efficacy in mechanical metalloproteins

Sacrificial bonding is a ubiquitous cross-linking strategy for increasing toughness that is found throughout nature in various biological materials such as bone, wood, silk and mussel byssal threads. However, the molecular mechanism of sacrificial bonding remains only poorly understood. Molecular modeling possesses a strong potential to provide insights into the behavior of these cross-links. Here we use Monte Carlo simulations to investigate the effect of reversible sacrificial binding sites on the mechanical properties of single linear polymer chains based on load-bearing metalloproteins found in the mussel byssus. It is shown that the topology of the bonds determines the position and spacing of sacrificial force peaks, while the height of these peaks is intimately tied to the magnitude of thermal fluctuations in the chain that are dependent on effective chain length. These results bear important implications for understanding natural systems and for the generation of strong and ductile biomimetic polymers.

The fan mussel Pinna rudis – occurrence and association with Pontonia pinnophylax in Terceira Island (Azores, NE Atlantic).

Event Abstract Back to Event The fan mussel Pinna rudis – occurrence and association with Pontonia pinnophylax in Terceira Island (Azores, NE Atlantic). Ricardo J. Pacheco1, João P. Barreiros2 and Sílvia C. Gonçalves1, 3* 1 GIRM - Marine Resources Research Group, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, Portugal 2 Azorean Biodiversity Group (CITA-A) and Platform for Enhancing Ecological Research & Sustainability (PEERS), University of the Azores, Portugal 3 IMAR - Marine and Environmental Research Centre, Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, Portugal Pinna rudis is known as one of the biggest fan mussels in the Azores, reaching a length of up to 80cm. The specimens are generally found attached by numerous byssus threads, with their pointed anterior ends buried vertically in the substratum (mud, sandy mud or gravel). However, currently there is a notorious lack of basic knowledge about this species, with no specific studies available in the literature. The objective of the present work was to study the occurrence of Pinna rudis in the coast of Terceira Island, by analysing the spatial distribution of the individuals, and investigate the symbiotic association with the shrimp Pontonia pinnophylax. Along the south coast of Terceira Island, 23 dives in 13 sites were performed using 30 meters transects. The dives were made from August to October 2004, limited by meteorological conditions. The length of each pinnid was measured in situ, and above the sediment, to avoid unnecessary removal. During the study period, 28 P. rudis were observed with a length range from 10 to 30cm. The majority measured about 10 to 15cm. The occurrence of P. rudis was not the same at the different sites selected, occurring mainly in small patches of sand in rocky bottoms. Only solitary individuals were observed. No correlation between the length of the animals and the depth of their occurrence was detected. The shrimp Pontonia pinnophylax was found living within the largest bivalves and at deeper depths. The occupancy rate of Pinna rudis by Pontonia pinnophylax was 57% (containing one or two shrimps). It is believed that the life cycles of these two species may be linked. The exact relationship between these two species remains unclear and needs to be studied experimentally; however it is believed that this is a mutualistic association. Keywords: Pinna rudis, occurrence, spatial distribution, Pontonia pinnophylax, symbiotic association Conference: IMMR | International Meeting on Marine Research 2014, Peniche, Portugal, 10 Jul - 11 Jul, 2014. Presentation Type: Poster Presentation Topic: BIODIVERSITY, CONSERVATION AND COASTAL MANAGEMENT Citation: Pacheco RJ, Barreiros JP and Gonçalves SC (2014). The fan mussel Pinna rudis – occurrence and association with Pontonia pinnophylax in Terceira Island (Azores, NE Atlantic).. Front. Mar. Sci. Conference Abstract: IMMR | International Meeting on Marine Research 2014. doi: 10.3389/conf.fmars.2014.02.00098 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Apr 2014; Published Online: 18 Jul 2014. * Correspondence: Prof. Sílvia C Gonçalves, GIRM - Marine Resources Research Group, School of Tourism and Maritime Technology, Polytechnic Institute of Leiria, Peniche, Portugal, scgoncalves@ipleiria.pt Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Ricardo J Pacheco João P Barreiros Sílvia C Gonçalves Google Ricardo J Pacheco João P Barreiros Sílvia C Gonçalves Google Scholar Ricardo J Pacheco João P Barreiros Sílvia C Gonçalves PubMed Ricardo J Pacheco João P Barreiros Sílvia C Gonçalves Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Mussels’ sticky feet lead to applications

Byssal threads and adhesive pads are clearly visible in this photo of a mussel attached to a pane of glass. Image courtesy of Phillip B. Messersmith.

Byssal Attachment Etchings: A New Bioerosion Trace on Recent Oysters

Byssate bivalves can be attached to hard substrates by byssal threads. Dissolution of the substrate to which they are attached may leave superficial bioerosion traces. This study reports the scars produced by byssus of Mytilus edulis and Aulacomya atra recorded in shells of Ostrea puelchana. Oyster valves were cut and gold-sputtered prior to scanning electron microscope observation. Each byssal thread leaves a characteristic scar on shells substrate. They etch an irregular trace on the substrate which may reach a diameter of several centimeters. These etching-traces comprise shallow round/oval holes of variable number and placement. A bundle of pits corresponding to fibers that compose the thread core was identified in the interior of each hole. We suggest that this trace could be included in the ethological class Fixichnia. The description of this trace would allow adjusting the composition of fossil assemblages and therefore paleoenvironmental interpretations in those cases in which mytilid shells have not been preserved. The recognition of this trace along with other ones of tracemakers with reotaxis or positive phototaxis could be useful in inferring the life habit of fossil biogenic substrates and in reconstructing their taphonomic history.

Marine mussel adhesion: biochemistry, mechanisms, and biomimetics

Common blue mussel (Mytilus edulis) is a sessile organism that has unique ability to attach to a wide array of organic and inorganic marine surfaces using its holdfast structures. Strong adhesion to surfaces is essential for mussel survival, movement, and self-defense. Mussel proteins from byssal thread are structural components connecting soft mussel tissues to marine surfaces via an adhesive plaque in the distal end, while adhesive proteins from byssal plaque are responsible for mussel adhesion. Adhesive proteins are small molecules containing a high proportion of post-translationally modified amino acids such as 3,4-dihydroxyphenylalanine (DOPA). High DOPA content, small molecular size, protein flexibility, the presence of metal ions, and a high oxidation state enable strong mussel adhesion to surfaces. Mussel adhesion mechanisms depend on the composition and interactions of mussel proteins, as well as their interactions with the environment. Difficulties in the extraction of mussel adhesion proteins hamper mechanism studies and their practical applications. Development of recombinant mussel proteins and biomimetics will advance our understanding of adhesion mechanisms. In this paper, recent advances in the characterization of mussel adhesive proteins (MAPs), mussel adhesion mechanisms, application of MAPs, and the development of biomimetic biopolymers are reviewed.

Novel Proteins Identified in the Insoluble Byssal Matrix of the Freshwater Zebra Mussel

The freshwater zebra mussel, Dreissena polymorpha, is an invasive, biofouling species that adheres to a variety of substrates underwater, using a proteinaceous anchor called the byssus. The byssus consists of a number of threads with adhesive plaques at the tips. It contains the unusual amino acid 3, 4-dihydroxyphenylalanine (DOPA), which is believed to play an important role in adhesion, in addition to providing structural integrity to the byssus through cross-linking. Extensive DOPA cross-linking, however, renders the zebra mussel byssus highly resistant to protein extraction, and therefore limits byssal protein identification. We report here on the identification of seven novel byssal proteins in the insoluble byssal matrix following protein extraction from induced, freshly secreted byssal threads with minimal cross-linking. These proteins were identified by LC-MS/MS analysis of tryptic digests of the matrix proteins by spectrum matching against a zebra mussel cDNA library of genes unique to the mussel foot, the organ that secretes the byssus. All seven proteins were present in both the plaque and thread. Comparisons of the protein sequences revealed common features of zebra mussel byssal proteins, and several recurring sequence motifs. Although their sequences are unique, many of the proteins display similarities to marine mussel byssal proteins, as well as to adhesive and structural proteins from other species. The large expansion of the byssal proteome reported here represents an important step towards understanding zebra mussel adhesion.

Antifouling activities of hymenialdisine and debromohymenialdisine from the sponge Axinella sp.

Being physically unprotected sessile organisms, marine sponges are thought to protect themselves from surface fouling through the use of antifouling secondary metabolites. In this study, the sponge Axinella sp. was extracted with methanol and then partitioned between organic solvents and water. Two main compounds, hymenialdisine (HD) and debromohymenialdisine (DBH), were isolated from the n-BuOH layer using Sephadex LH-20 and C-18 column chromatography. The antifouling activity of HD and DBH were evaluated using the test of byssus thread production with the green mussel Perna viridis, and the settlement assays with the bryozoan Bugula neritina larvae and the green alga Ulva prolifera spores. Both HD and DBH were found to exhibit significant antifouling activities against P. viridis (EC50 values of 31.77 and 138.18 μg ml−1, respectively), B. neritina (EC50 values of 3.43 and 8.17 μg ml−1, respectively) and U. prolifera (EC50 values of 8.31 and 0.67 μg ml−1, respectively). Our results suggested that HD and DBH may play a role in chemical defense against fouling in Axinella sp.

Lipid-Specific β-Sheet Formation in a Mussel Byssus Protein Domain

Intrinsically disordered proteins (IDP) or regions (IDR) can adopt multiple conformational states, depending on the interaction partners they encounter. This enables proteins or individual domains to fulfill multiple functions. Here, we analyzed the flank sequences of preCol-NG, one of three collagenous proteins of a mussel byssus thread governing its mechanical performance. preCol-NG comprises a collagen domain and nonrepetitive termini enclosing specific flank regions characterized by tandem repeats known from silk proteins, protein elastomers, and plant cell wall-associated proteins. We recombinantly produced a protein mimicking the M. galloprovincialis preCol-NG C-terminal flank region. The protein was intrinsically unfolded in solution, even at elevated temperatures. However, upon contact with small unilamellar vesicles (SUVs) reversible β-structure formation occurred, reminiscent of partitioning-folding coupling. This behavior of preCol-NG flank domains likely impacts byssogenesis and sheds new light on a distinct mechanism of how fibrous protein materials might be achieved by lipid-induced self-assembly in nature.

Effects of injured conspecifics and predators on byssogenesis, attachment strength and movement in the blue mussel, Mytilus edulis

Mussels respond to threats from predators by increasing anti-predator traits, which include a suite of inducible defenses. Blue mussels (Mytilus edulis) can modify the strength, number and attachment site of byssal threads in response to water borne cues from predators and injured conspecifics. We quantified byssal thread production, attachment strength and movement in blue mussels of two size classes in response to effluent from the American lobster Homarus americanus, the rock crab Cancer irroratus, the sea star Asterias rubens, and injured conspecific mussels. In a factorial laboratory experiment, effluent from the predatory crab, C. irroratus, resulted in higher numbers of functional byssal threads compared only to exposure to injured conspecific mussels, and not to any other treatment group. Large mussels produced stronger byssal attachments than small mussels. Over 24h, small mussels formed and released more byssus bundles than large mussels, an indication of increased movement. Small mussels started producing byssal threads sooner than large mussels. Mussels exposed to effluent from injured conspecific mussels began producing byssal threads earlier, compared to the control and not to any other treatment group. Our results show that byssogenesis was influenced by predator type and mussel size, whereas attachment strength and movement depended on mussel size. This study highlights the ability of two size classes of blue mussels to selectively alter byssal thread production and movement in the presence of injured conspecifics and potential predators.

Protein Gradient Films of Fibroin and Gelatine

Gradients are a natural design principle in biological systems that are used to diminish stress concentration where materials of differing mechanical properties connect. An interesting example of a natural gradient material is byssus, which anchors mussels to rocks and other hard substrata. Building upon previous work with synthetic polymers and inspired by byssal threads, protein gradient films are cast using glycerine-plasticized gelatine and fibroin exhibiting a highly reproducible and smooth mechanical gradient, which encompasses a large range of modulus from 160 to 550 MPa. The reproducible production of biocompatible gradient films represents a first step towards medical applications.

Impact tolerance in mussel thread networks by heterogeneous material distribution

The Mytilidae, generally known as marine mussels, are known to attach to most substrates including stone, wood, concrete and iron by using a network of byssus threads. Mussels are subjected to severe mechanical impacts caused by waves. However, how the network of byssus threads keeps the mussel attached in this challenging mechanical environment is puzzling, as the dynamical forces far exceed the measured strength of byssus threads and their attachment to the environment. Here we combine experiment and simulation, and show that the heterogeneous material distribution in byssus threads has a critical role in decreasing the effect of impact loading. We find that a combination of stiff and soft materials at an 80:20 ratio enables mussels to rapidly and effectively dissipate impact energy. Notably, this facilitates a significantly enhanced strength under dynamical loading over 900% that of the strength under static loading.