An integrated pest management program for burrowing shrimp control in oyster aquaculture

Use of extractable lipofuscin to estimate age ­structure of ghost shrimp populations in west coast estuaries of the USA

“…Strong recruitment of Neotrypaea californiensis in the early 1990s is evident from the long-term yearly monitoring data from the Palix River in Willapa Bay (Feldman et al 2000). Since that time, recruitment has been relatively low and population density has correspondingly declined (Dumbauld et al 2006). However, LF-based age structure from the current study indicates that at least 9 age classes in the present population at the Palix River show 4 and 5 yr old shrimp predominating (Fig.…”

“…Population age structure, year-class strength and life expectancy are parameters that can be used to estimate annual recruitment of a species when young-ofyear are scarce or difficult to sample (Hilborn & Walters 1992). The current monitoring program for IPM of ghost shrimp involves conducting annual surveys to estimate population density and annual recruitment in multiple West Coast estuaries (Dumbauld et al 2006). Strong recruitment of Neotrypaea californiensis in the early 1990s is evident from the long-term yearly monitoring data from the Palix River in Willapa Bay (Feldman et al 2000).…”

“…More recent studies used size-frequency data to estimate growth and the number of age classes in several Oregon and Washington populations, suggesting the animal lives to be from 3 to 5 yr old (Bird 1982, Dumbauld et al 1996. Annual larval recruitment of the shrimp to Willapa Bay has been shown to be variable, and recent studies hint at the possibility of missing size/year classes (Dumbauld et al 2006). In the current study, assessment of population age structure using analysis of LF as an age biomarker was successful in resolving up to 13 separate age classes in Yaquina Bay and 9 age classes in Willapa Bay.…”

“…Since the 1960s, oyster growers have controlled burrowing shrimp populations by applying a pesticide, carbaryl, to intertidal mudflats (WDF 1970). Increasing concern over the environmental impacts associated with using carbaryl as a form of control has led the industry to pursue integrated pest management (IPM) of burrowing shrimp on oyster grounds (DeWitt et al 1997, Dumbauld et al 2006. Several critical needs for implementing a successful IPM strategy have been identified, including the development of methods for conducting burrowing shrimp population censes and constructing population models (DeWitt et al 1997).…”

Density-dependent effects of an introduced oyster, Crassostrea gigas, on a native intertidal seagrass, Zostera marina

“…4). Current onground oyster culture practices in Willapa Bay typically result in oyster cover that starts below 20% (average 8%, range = 5−20% cover and 10−40 pieces of cultch m −2 ), and then oysters grow and cover increases (average 20%, range = 5−35% cover), but cover can be 100% when oysters are left to form patchy reefs or hummocks, as occurs in the southern half of Willapa Bay (Dumbauld et al 2006). Disturbances associated with bed maintenance and harvest may additionally reduce eelgrass density for a period of 2 to 4 yr (Tallis et al 2009).…”