NOAA CZM - Conservation Targeting

Deliverables for NOAA CZM gran

Prodigious Pearls: an extreme incidence of pearl formation in the ribbed mussel

All calcareous molluscs are capable of producing pearls in response to an irritant, and the literature abounds with records of pearls in numerous taxa. Here, we report on the first-known documented case of pearls in the ribbed mussel, Geukensia demissa, as well as the highest density (#/individual) of pearls reported in any bivalve. At a single location in the Chesapeake Bay, pearls were incidentally discovered in ribbed mussels from samples collected in 2016. Numbers per individual ranged from 0 to 1,397, and ranged in size from 0.1 to > 2.0 mm, with a median diameter of ~0.5 mm. A targeted follow-up collection in 2022 found pearls in 23 of 40 mussels collected across the surface of the marsh. When present, counts ranged from 4 to 2361 pearls per mussel, with a median of 522 pearls. The median pearl diameter was 0.42 mm. A statistical analysis of pearl counts found that both distance into the marsh (m) and mussel density (individuals/m2) were positively correlated with the number of pearls, while mussel length (proxy for age) did not have an additional directional effect. Histolopathological analysis of the in situ pearls suggested an organic irritant, likely a trematode parasite. The most likely candidate is Proctoces maculatus, but genetic analyses have yet to provide a positive identification

Effects of terrestrial-aquatic connectivity on an estuarine turtle

ABSTRACT Aim Estuaries world-wide have been modified or fragmented due to human stressors in their terrestrial and aquatic components. Estuary fragmentation often results in reductions in species richness, diversity and connectivity. Effects of human modification on estuaries have been well studied, but less is known about how land use alters connectivity of the terrestrial-aquatic ecotone. We studied the relationship between terrestrial-aquatic connectivity and the distribution of an estuarine turtle, diamondback terrapin (Malaclemys terrapin). Location Chesapeake Bay, Virginia, USA. Methods We conducted diamondback terrapin surveys at 165 sites from late spring to mid-summer in 2012 and 2013. We evaluated associations between terrapin occurrence, land use, salt marsh, shoreline armouring and crabbing intensity in concentric-circular neighbourhoods ranging from 0.27 to 2 km to cover daily and annual terrapin movements. We used occupancy modelling and model averaging to identify key terrestrial and aquatic variables explaining heterogeneity in terrapin occupancy. We evaluated the final model with an independent data set and identified occurrence thresholds for key variables. Results Diamondback terrapin occupy areas with ≥ 10% of marsh within a 750-m neighbourhood, ≤ 17% armoured shoreline within a 1-km neighbourhood, ≤ 20% of agriculture within a 500-m neighbourhood, ≤ 33% low-density housing within a 270-m neighbourhood and ≤ 9 active crab pots within a 270-m neighbourhood. Our model performed well when evaluated with an independent data set. Main conclusions We are the first to identify thresholds and quantify negative associations between the distribution of diamondback terrapin and alterations to terrestrial-aquatic connectivity from land development, shoreline armouring, and fishing activity. Because diamondback terrapin responses are reflective of changes in coastal habitats, especially marshes, terrapin occurrence can be used to direct wetlands conservation and restoration efforts

Nursery habitat use by juvenile blue crabs in created and natural fringing marshes

Climate change and coastal development pressures have intensified the need for shoreline protection. Nature-first approaches that use natural habitats, particularly marshes, are being promoted globally as ecologically-beneficial alternatives to grey infrastructure. The ability of these novel shorelines to provide nursery habitat to blue crab, an ecologically and economically important species along the Atlantic and Gulf coasts of the United States, has not been fully evaluated. We quantified the abundance and size distribution of juvenile blue crabs from a chronosequence of living shorelines (created fringing marshes) spanning 2 to 16 years in age (since construction) compared with paired natural fringing marshes in the southern Chesapeake Bay. Both created and natural fringing marshes are being used by blue crabs as primary nursery habitats. Despite interannual differences in abundance, young blue crabs (≤ 2.5 cm carapace width) were observed in similar densities and sizes at living shoreline and natural marshes. The age of the living shoreline was not related to blue crab density, indicating that even the youngest living shorelines (2 years) were providing nursery habitat. Young juvenile blue crabs were more abundant in more isolated marshes and in marshes inundated for longer periods of time each tidal cycle, which may be evidence for habitat-limitation. Our results provide evidence that juvenile blue crabs are comparably using natural and created fringing salt marshes as primary nursery habitat. Although the relative importance of salt marshes as young crab nursery habitat is not fully understood and likely varies by system, the value of marshes within a suite of available structural nursery habitats may increase under a changing climate. The potential for living shorelines to serve as nursery habitat for an economically important species may provide additional incentive to implement these climate adaptation strategies

Living Shorelines Achieve Functional Equivalence to Natural Fringe Marshes across Multiple Ecological Metrics

This is the data, script, and figure repository for the manuscript titled, "Living Shorelines Achieve Functional Equivalence to Natural Fringe Marshes across Multiple Ecological Metrics" published in PeerJ