Energetics of the extremely long-living bivalve Arctica islandica based on a Dynamic Energy Budget model

Abstract

The ocean quahog Arctica islandica is the longest-living mollusk on Earth with a lifespan of at least 500 years. The slow senescence of this bivalve has promoted a great interest in its metabolic strategy. A dynamic energy budget (DEB) model was applied to describe how this species allocates its energy to maintenance, growth, maturation, and reproduction in a variable environment. We studied the relationship between A. islandica growth, lifespan, and food availability at eight different locations in the North Atlantic Ocean. Our results indicate that A. islandica's extreme longevity arises from its low somatic maintenance cost [̇] and low ageing acceleration ℎ̈, but there was not a direct relationship between food availability and lifespan in these A. islandica locations. Monkey Bank (North Sea), Iceland, and Ingøya (northern Norway) had the highest food availability estimates of all the localities but did not have the lowest longevities, in contrast to the theory of caloric restriction.

Persistent Multidecadal Variability Since the 15th Century in the Southern Barents Sea Derived From Annually Resolved Shell‐Based Records

“…The influence of local environmental factors controlling shell growth and activity in this population has also been studied in detail at Ingøya by Ballesta‐Artero et al. (2017, 2019).…”

Microstructural Mapping of Arctica islandica Shells Reveals Environmental and Physiological Controls on Biomineral Size

“…Just after settlement of the larvae, metabolism and shell growth occur only at slow rate due to the small body size of the individuals (Figure 9). However, during this early stage of life, shell growth also accelerates most rapidly, because it receives the largest proportion of the increasing metabolic power in order to improve individual survival chances (Kooijman and Kooijman, 2010;Ballesta-Artero et al, 2019). Accordingly, the shell of young A. islandica grows faster than its soft body (Murawski et al, 1982).…”

“…Accordingly, the maximum somatic production activity is attained after the formation of the largest BMUs. After maturation, shell growth reaches the negative asymptotic stage (Philipp and Abele, 2010) because the majority of available metabolic energy is now directed toward reproduction (Begum et al, 2010;Kooijman and Kooijman, 2010;Ballesta-Artero et al, 2019). However, the onset of sexual maturity varies greatly between localities and among specimens (Thompson et al, 1980b;Cargnelli, 1999;Thorarinsdottir and Steingrimsson, 2000), whereas BMU size maxima were always attained around age seven to nine (Figure 5).…”

A new phase in DEB research

“…It also facilitates judging how current parameter estimates of a new entry at hand relate to those of taxonomically related ones (see e.g. Ballesta-Artero et al, 2018;Sadoul et al, 2018, this issue), since a good fit for the wrong reasons is always a risk to consider. Maximization of the goodness of fit is just one of the estimation criteria, which should not be pushed to the extreme, since many trivialities, such as temperature and/or food density not actually being constant, can cause deviations.…”