|An ecological assessment of the non-indigenous isopod, Synidotea laticauda, in Delaware Bay|
Boyd, S.G. (2008). An ecological assessment of the non-indigenous isopod, Synidotea laticauda, in Delaware Bay. MSc Thesis. Rutgers, The State University of New Jersey: New Brunswick. 82 pp.
Synidotea laticauda is a non-indigenous marine isopod that has been documented in Delaware Bay since 1998. Due to its relatively resent arrive there is a general lack of scientific knowledge about the impact this isopod may have on local ecosystems. Extremely high seasonal abundances, documented over the past three years, suggest the potential for a strong impact. A presence-absence survey conducted during the summer of 2006 documented S. laticauda along portions of both the New Jersey and Delaware coasts of Delaware Bay and on several oyster seed beds within the bay. Isopods were only present in portions of the bay containing anthropogenic structures and salinities between 2 and 22. Synidotea laticauda were not observed along the Atlantic coasts of New Jersey or Delaware. Temperature-salinity challenges found that S. laticauda die quickly in fresh water but can survive in salinities of 30 and 35. The temperature-salinity challenges also found that S. laticauda survived in water temperatures typical for Delaware Bay. Although lethargic, isopods experienced very little mortality at 5 ºC; however, high mortality was experienced above 25 ºC. Regular monitoring of recently deployed (clean) and continuously deployed (fouled) cages in the Maurice River identified a preference for structures accumulating biological fouling. Several trophic interactions between S. laticauda and the biota of Delaware Bay were also identified in this study. Single-choice feeding trials identified predation on nine fauna and flora species and established S. laticauda as an omnivore capable of exploiting multiple food resources within the bay. Furthermore, gut content analyses of fish collected from the Maurice and Nantuxent Rivers indicate that a minimum of four predatory fish species consume S. laticauda, although it does not appear to be an important component of their diet. Collectively these findings indicate S. laticauda will persist in portions Delaware Bay but with a nominal ecological impact.