A Ship's Ballasting History As an Indicator of Foraminiferal Invasion Potential – an Example from Prince William Sound, Alaska, Usa

Abstract

We investigated the potential role of ballast sediment from coastal and transoceanic oil tankers arriving and de-ballasting in Port Valdez as a vector for the introduction of invasive benthic foraminifera in Prince William Sound, Alaska. Forty-one ballast sediment samples were obtained during 1998–1999 from 11 oil tankers that routinely discharged their ballast in Prince William Sound after sailing from other West Coast (Los Angeles/Long Beach Harbor, San Francisco Bay, and Puget Sound) or foreign ports (Japan, Korea, and China) where they originally ballasted. Forty of these samples contained benthic foraminifera, including 27 (66%) with the introduced species Trochammina hadai Uchio from nine (81%) of the ships. In all, 59 species were recovered and foraminiferal abundance peaked at 27,000 specimens per gram dry sediment. Of the 41 samples, three were stained and living benthic foraminifera were recovered in all three of them. The entrained foraminifera reflected the number of times ballasting occurred (single or multiple sources), the location of ballasting (estuarine or offshore), and post-acquisition alteration of the sediment (i.e., growth of gypsum crystals at the possible expense of calcareous tests). In temperate regions, sediment samples resulting from single-source ballasting in estuaries (SSBE), multiple-source ballasting in estuaries (MSBE), single-source ballasting offshore (SSBO), and a combination of SSBO and SSBE or MSBE, typically contained increasingly higher species richness, respectively. The potential for foreign species invasion is dependent on the presence of viable candidates and their survivability, their abundance in the ballasting location, and the number of times ballasting occurs, most of which are evident from the ship's ballasting history. We estimate that 442.1 billion to 8.84 trillion living foraminifera were introduced into Port Valdez in a single year, suggesting it is quite likely that an invasive species could be successfully established there. Trochammina hadai is a good example of a successful invasive in Prince William Sound for the following reasons: 1) the species is abundant enough in U.S. West Coast and foreign ports where ballasting occurs that sufficient individuals needed for reproduction may be transported to the receiving waters; 2) Port Valdez, in particular, receives repeated and frequent inoculations from the same source ports where T. hadai is present; 3) large quantities of sediment are taken up by commercial vessels during ballasting and benthic foraminifera occur in abundance in ballast sediment; 4) ballast sediment provides a suitable environment in which benthic foraminifera can survive for extended periods of time during transport; 5) T. hadai flourishes in a wide range of temperatures and environmental conditions that characterize both the ports where ballasting takes place as well as in Port Valdez where de-ballasting occurs; and 6) the species is capable of asexual reproduction and possibly the ability to form a dormant resting stage, both of which have the potential to lower the threshold for colonization. Clearly, ballast sediment is a viable vector for the introduction of T. hadai and other invasives into Alaskan ports and elsewhere worldwide.

Alien and cryptogenic Foraminifera in the Mediterranean Sea: A revision of taxa as part of the EU 2020 Marine Strategy Framework Directive

“…Ballast water is generally invoked to be among of the major pathways for the introduction of nonindigenous marine species (Ruiz et al, 1997;Carlton et al, 1999;Molnar et al, 2008;Seebens et al, 2016), but hardly anything is kown about the potential role of transoceanic ship deballasting as a vector for the introduction of alien foraminifera in the Mediterranean Sea (Galil & Hülsmann 1997;McGann et al, 2020). The release of ballast water and the transport stowaway pathway related to shipping traffic (biofoulers and hitchhikers) have been widely suspected as vectors for the introduction of non-native foraminifera (Hayward, 1997;Hayward et al, 1999;McGann et al, 2000;Calvo-Marcilese & Langer, 2010;Polovodova Asteman & Schönfeld, 2016;Eichler et al, 2018;Deldicq et al, 2019), has led to a breakdown of classical biogeographic regions and is considered a major vector for Red-to-Med alien species invasions (Zenetos et al, 2012).…”

“…1). Potential pathways for the introduction (Table 1) are inferred from habitat preferences, live modes (epiphytic, epifauna, infauna), field and laboratory studies (Finger 2017;Langer, 1993;Jorissen, 1987;Hyams et al, 2002;Alve & Goldstein, 2003;Guy-Haim et al, 2017;Weinmann et al, 2019;McGann et al 2020). Additional information is provided when a species was recorded in fossil or core material and when new molecular genetic data were available.…”

The San Francisco Estuary, USA as a reference section for the Anthropocene series

“…Today the San Francisco Estuary is a highly modified ecosystem, with approximately 52% of all non-native species having been introduced to the estuary via shipping, either by fouling or boring into ship hulls, in solid ballast, ballast waters, or ballast sediment of ships (Cohen and Carlton, 1995; McGann et al, 2019). Some 39 species are also thought to have been introduced as a result of the shipments of Atlantic and Japanese oysters in the late 19th and early 20th centuries, respectively (Cohen and Carlton, 1995).…”