Large-Scale Zostera marina (eelgrass) Restoration in Chesapeake Bay, Maryland, USA. Part I: A Comparison of Techniques and Associated Costs

Abstract

The Chesapeake Bay, like many other temperate estuaries, has exhibited dramatic declines in the abundance of submerged aquatic vegetation (SAV) during the later half of the twentieth century. Because of the functions SAV serve in maintaining a healthy estuarine ecosystem, SAV restoration has become an important component of Chesapeake Bay restoration. Specifically, recent water quality improvements in areas from which populations of Zostera marina (eelgrass) have been extirpated have suggested that Z. marina restoration could succeed. Early restoration efforts involved transplanting Z. marina plants from healthy source beds to restoration locations, but this was labor intensive, time consuming, expensive, and potentially detrimental to donor beds. This multi-year project investigated new techniques for large-scale Z. marina seed collection and processing and compared two seed dispersal methods to evaluate cost effectiveness. Tens of millions of mature Z. marina seeds were collected through snorkeling, SCUBA, or with a mechanical harvester. Seed storage conditions and processing techniques were manipulated in order to maximize seed yield. Seeds were dispersed using two methods: spring seed buoys and fall seed broadcasts. Our costs for planting 1 ha of bottom with Z. marina seeds ranged from $6,674 to $165,699 depending on seeding density and dispersal method used. The average cost per Z. marina seed was $0.17. Interannual variations in seed collection yield and seed viability after summer storage had great impact on final costs. Our results suggest that the use of seeds for large-scale Z. marina restoration offers a competitive advantage to more traditional transplanting methods.

Effects of a simulated heat wave on photophysiology and gene expression of high- and low-latitude populations of Zostera marina

“…in the Adriatic Sea, will not be able to disperse around the Iberian Peninsula and reach high-latitudes. With Z. marina being successfully transplanted over large scales in many studies (reviewed by Fonseca et al 1998, Busch et al 2010), now might be the time to apply more drastic conservation measures to these important species. Although we did not show that Z. marina from the Adriatic Sea survives heat waves better than its northern conspecific over relatively short time scales, we cannot rule out that over an entire year cycle, or even over the lifetime of a clone, there are indeed differences among populations.…”

An Introduction to a Special Issue on Large-Scale Submerged Aquatic Vegetation Restoration Research in the Chesapeake Bay: 2003-2008

“…New techniques and technologies described in this issue allow submerged aquatic plants to be planted at scales (tens of hectares) that would have been unattainable with existing technologies only a few years ago. Furthermore, the costs of conducting these plantings are on a downward trend as the understanding of the limiting factors increases and as new advances are made in technology development (Shafer & Bergstrom 2008; Busch et al 2010).…”

“…Marion and Orth (2010 a ) and Golden et al (2010) describe the development and testing of innovative new mechanical equipment for harvesting and planting seeds of Z. marina . Busch et al (2010) focus on a comparison of the cost‐effectiveness of mechanical harvesters and planters with manual methods. Their results confirm that seeding offers a cost‐effective alternative to transplanting for some SAV species.…”

Aquaculture of marine non‐food organisms: what, why and how?

“…It is also important to note that seagrass restoration through seed collection, processing and dispersal offers economic advantages as compared to traditional transplanting approaches (Busch et al . ).…”