The allometry of oysters: spatial and temporal variation in the length–biomass relationships forCrassostrea virginica

Abstract

We examine the relationship of biomass B and length L in the eastern oyster Crassostrea virginica by focusing on the scaling exponent b in the allometric equation B = aLb using four datasets: Delaware Bay, Chesapeake Bay, Galveston Bay and a regionally extensive compilation from the NOAA Mussel Watch Program. The average value of the scaling exponent in Delaware Bay and Chesapeake Bay is about 2. For Galveston Bay, the value is distinctly higher, near 2.6. Over all Mussel Watch sites, the value is again near 2. Within Delaware Bay, the salinity gradient exerts an important effect. Shells are longer for their meat weight at lower salinities. The range of scaling exponents revealed by Mussel Watch data is exceedingly large (b < 1 to >3). Scaling exponents below 2.5 are unusual in bivalves. Among bivalves, only other oyster taxa have comparably low scaling exponents averaging near 2. We propose that oyster biomass routinely scales nearer the square of the length rather than the cube and that this is a constraint imposed by the exigency of carbonate production for reef maintenance and accretion in the face of high rates of taphonomic degradation. The adaptation as a reef builder requires the formation of carbonate that rapidly breaks down, thus requiring that carbonate produced be maximized. A biomass-to-length scaling exponent of 2 provides a mechanism to maximize shell production relative to biomass, while at the same time providing maximum surface area for the all-important settling of oyster spat to maintain the population.

Comparative morphological analysis of diploid and triploid oysters, Crassostrea gigas, farmed in the Black Sea

“…Shell growth in bivalves is usually determined by the substrate quantity, population density (overpopulation), tidal and wave intensity, current speed, depth, feeding spectrum, etc. [24,27,28]. For cultivating oysters, additional factors are the method of growing (construction of oyster cages, their location in the sea, etc.)…”

Рост И Сроки Получения Товарной Триплоидной Устрицы В Лимане Донузлав (Чёрное Море, Крым)

“…На процессы роста раковины оказывают влияние качество субстрата, плотность популяции (перенаселение), интенсивность волновых явлений и течений, глубина, спектр питания и т. д. [10,21,27]. Так, у C. madrasensis с размерами менее 3,5 см высота и длина имеют близкие значения, форма раковины округлая [21].…”

“…Значение 3 соответствует трёхмерному характеру двустворчатой оболочки большинства моллюсков. Многочисленные исследования показали, что экспонента b обычно находится между 2,5 и 3, а значения ниже 2,5 редки для моллюсков [27]. Несмотря на это, показатель, установленный для различных видов устриц, является достаточно низким и составляет от 1,5 до 2,5 (в среднем -около 2).…”

“…Таким образом, существует чёткая тенденция: биомасса устрицы рассчитывается как квадрат длины, а не как куб. Общее среднее значение b = 2,0 может быть принято для ряда крассостреид, в том числе для C. gigas [27].…”

An Overview of Factors Affecting Distribution of the Atlantic Surfclam (Spisula solidissima), a Continental Shelf Biomass Dominant, During a Period of Climate Change

“…Like most bivalves, surfclam adult size is dependent on the relative rates of respiration and ingestion; both are temperature controlled. In bivalves, respiration typically scales as the cube of the length (Powell & Stanton 1985, Freitas et al 2009, Powell et al 2015b, whereas ingestion, which is a function of the two-dimensional surface of the gill, tends to scale as the square of the length (Powell et al 1992, Hofmann et al 2006, van der Meer 2006. This differential scaling produces physiological challenges for large-sized bivalves; at some point, ingestion is just able to meet respiratory demands and, perhaps, reproduction, and at that point, growth ceases.…”