Biotic and abiotic factors influencing attachment strength of blue mussels Mytilus edulis in suspended culture

Abstract

Mussels secrete byssal threads regularly to the substratum, and the strength of these threads can fluctuate with time. The present study examined weekly variations in the attachment strength of 2 yr old cultured mussels Mytilus edulis on submerged longlines in a semi-enclosed lagoon from late May to mid-October. Some possible factors influencing attachment strength were investigated: environmental factors (temperature, food availability, wind velocity and hydrodynamic conditions such as current velocity, turbulence and wave height) and reproductive condition were measured concurrently. Attachment strength was measured directly on cultured mussels using a dynamometer. Attachment strength varied 2-fold from summer to fall, a difference related not only to the number of byssal threads but also to their individual strengths. The hierarchical influence of each factor on attachment strength is discussed. Our results suggest that spawning seemed to be correlated with an important decrease (-32%) in attachment strength, and that water temperature (negative relationship) and turbulence (positive relationship) were the most important factors explaining the variation in mussel attachment strength. In contrast to previous studies carried out in intertidal zones, no trade-offs were observed between reproduction and attachment strength.

Changing environments and structure–property relationships in marine biomaterials

“…One might reasonably expect tenacity to be largely determined by the number of threads in the byssus; however, in the intertidal mussels of Narragansett Bay (Rhode Island), Moeser and Carrington observed that thread quality, more than number, determined tenacity (Moeser and Carrington, 2006). A similar trend was observed in cultured subtidal mussels at Ile de Madeleine lagoon, Quebec, Canada (Lachance et al, 2009). In the Narragansett mussels, the mean breaking strength and extensibility of threads made in late winter to early spring was 50-60% higher than that of threads in other seasons.…”

“…The tested threads had inferior mechanical properties under normal testing conditions, therefore scenarios A or C seem more likely than B (Fig.1). Moreover, mussels in these studies were in poor physiological condition, suggesting pathway A (Moeser and Carrington, 2006); added to this, even the quality of normal threads made earlier became compromised, indicating a combination of A and C. In a related study involving subtidal mussels (Lachance et al, 2009), loss in thread quality was shown to happen quite rapidly -in the course of days not months. As proposed earlier (Moeser and Carrington, 2006), enhanced thread deterioration seems the best explanation.…”

“…In cultured subtidal Mytilus edulis, byssal thread breaking strength was strongly and negatively correlated with temperature in mussels (Lachance et al, 2009). At least one byssal protein (thread matrix protein, TMP) is extremely prone to temperature-dependent deamidation, but the effect of deamidation on mechanical properties is not yet known.…”

Byssus secretion of Mytilus galloprovincialis: effect of site at macro- and micro-geographical scales within Ría de Vigo (NW Spain)

“…We have reported here the importance of the macro-geographical factor of site on a number of 137 Hunt & Scheibling (2001) and Lachance et al (2008). The higher tenacity reported for the outer exposed CE mussels was not only due to the thicker byssal threads these animals secreted, specifically at its distal sections, but was also a consequence of the fact that these threads were mechanically more effective (Table 3) and had a higher amount of the basic amino acids histidine and lysine (Table 1).…”

“…sheltered vs. exposed areas) may cause several morphological changes in corporal parameters of the mussels, such as shell thickness, height and width (Raubenheimer & Cook 1990, Akester & Martel 2000, Steffani & Branch 2003, Beadman et al 2003, and shift energy allocation patterns to other vital structures. Unbalanced patterns in energy allocation between shell and soft tissue growth, reproductive tissues and byssal attachment may be more common in littoral zones with limited food availability than in subtidal environments where food resources are more abundant (Lachance et al 2008).…”