A conservation palaeobiological perspective on Chesapeake Bay oysters

Abstract

The eastern oyster plays a vital role in estuarine habitats, acting as an ecosystem engineer and improving water quality. Populations of Chesapeake Bay oysters have declined precipitously in recent decades. The fossil record, which preserves 500 000 years of once-thriving reefs, provides a unique opportunity to study pristine reefs to establish a possible baseline for mitigation. For this study, over 900 fossil oysters were examined from three Pleistocene localities in the Chesapeake region. Data on oyster shell lengths, lifespans and population density were assessed. Comparisons to modern Crassostrea virginica , sampled from monitoring surveys of similar environments, reveal that fossil oysters were significantly larger, longer-lived and more abundant than modern oysters from polyhaline salinity zones. This pattern results from the preferential harvesting of larger, reproductively more active females from the modern population. These fossil data, combined with modern estimates of age-based fecundity and mortality, make it possible to estimate ecosystem services in these long-dead reefs, including filtering capacity, which was an order of magnitude greater in the past than today. Conservation palaeobiology can provide us with a picture of not just what the Chesapeake Bay looked like, but how it functioned, before humans. This article is part of a discussion meeting issue ‘The past is a foreign country: how much can the fossil record actually inform conservation?’

Molecular identification, life cycle characterization, and hatchery seed production of dwarf oysters from the Ebro Delta (Spain)

“…1.6 years of age for animals of 30 mm, 3.5 years for those of 40 mm, and up to 10 years to attain maximum sizes around 45 mm (Rosique et al, 1995;this study). This estimate of maximum age is coherent with that indicated for O. edulis, which may range from 10 to 14 years and with other species also reaching an age of 15 years or more, depending on preferential harvesting of larger animals (Richardson et al, 1993;Lockwood and Mann, 2019). The obtained growth equation was also similar in shape to that found for O. edulis, with the phase of asymptotic reached at ca.…”

Indigenous oyster fisheries persisted for millennia and should inform future management

“…While a crucial source of information, capitalist commercial harvest records generally only extend back 100–200 years. Recent conservation paleobiology studies of fossil reefs improve the time depth of these studies 8 , 9 . With few exceptions, however, Indigenous fisheries are a forgotten information source for past fisheries that span thousands of years across a range of environmental and anthropogenic changes.…”

An Assessment of the Potential Value for Climate Remediation of Ocean Calcifiers in Sequestration of Atmospheric Carbon

“…The paragraphs above demonstrate the crucial contribution that shellfish have made to human development in the past and there is growing appreciation of the continuing role that mariculture can play in food production in the future [95]. We wish to go much further and convey the potential value to humanity of a marine environment properly managed as a carbon capture facility, which many recent reports suggest to us to be a viable and worthwhile activity [51,[104][105][106][107][108].…”