Identifying the environmental factors driving larval settlement is crucial to understanding the population dynamics of marine invertebrates. EU-funded research feeds into a new study that takes three environmental factors into consideration in an attempt to predict larval presence and intensity.
The impact of three environmental factors – solar irradiance, wind regime and continental runoff – on Mytilus galloprovincialis settlement patterns were analysed by researchers who have recently published their findings in Scientific Reports. Results show solar irradiance indirectly influences the settlement process, leading the team to suggest the use of this meteorological variable to predict settlement occurrence.
Marine benthic invertebrates have synchronised reproductive cycles to produce larvae under optimal conditions for survival. The longer the species remain at larval stage the more threats to their survival they face, such as predation and transportation to unsuitable places. Establishing the factors impacting on cycle timing and density can aid in the understanding of how environmental changes may affect population dynamics.
Influence of solar irradiance
The team managed to establish a functional generalised additive model, (designed for association studies between a scalar response and a functional predictor). This considered the influence of the three environmental factors above and can provide a prediction of settlement. Results, to which the EU-funded CLIMEFISH project contributed, indicate solar irradiance allows the prediction of the beginning and end of a settlement cycle a month in advance. Solar irradiance during the late winter indirectly drove the intensity of the onset of the settlement.
The team conducted weekly monitoring over a five-year period on Mytilus galloprovincialis settlements situated around artificial, suspended substrates, to establish interannual variability in the settlement patterns. Previous studies have focused on the link between dispersal and hydronamics and have connected the temporal pattern of settlement to reproductive cycles. The paper, ‘Solar irradiance dictates settlement timing and intensity of marine mussels’ shines further light on larval settlement, a vital phase in the animal’s lifecycle as it links larval and benthic stages and plays a pivotal role in population density.
Impact of findings
Mussels are dominant organisms on many rocky shores around the world, playing a significant role as both habitat and prey for a variety of organisms. Mussel culture is also important commercially, for example, the paper explains the northern boundary of the Iberian-Canary Current upwelling system is characterised by high mussel production.
The CLIMEFISH project aims to help ensure that the increase in seafood production comes in areas and for species where there is a potential for sustainable growth, given the expected developments in climate, thus contributing to robust employment and the sustainable development of rural and coastal communities.
For more information, please see: CORDIS project web page
Isabel Fuentes-Santos, Uxío Labarta, X. Antón Álvarez-Salgado & Mª José Fernández-Reiriz. 2016. Solar irradiance dictates settlement timing and intensity of marine mussels. Scientific Reports 6, Article number: 29405 (2016). doi:10.1038/srep29405
Mathew W. McLean, Giles Hooker, Ana-Maria Staicu, Fabian Scheipl, and David Ruppert. Functional Generalized Additive Models. J Comput Graph Stat. 2014; 23(1): 249–269. Published online 2014 Feb 12. doi: 10.1080/10618600.2012.729985