Assessing Freshwater Habitat of Adult Anadromous Alewives Using Multiple Approaches

Martha E Mather,John T Finn,Joseph M Smith,Roxann D Cormier,Robert M Muth,Holly J Frank

doi:10.1080/19425120.2012.675980

Abstract

AbstractAfter centuries of disturbance, environmental professionals now recognize the need to restore coastal watersheds for native fish and protect the larger ecosystems on which fish and other aquatic biota depend. Anadromous fish species are an important component of coastal ecosystems that are often adversely affected by human activities. Restoring native anadromous fish species is a common focus of both fish and coastal watershed restoration. Yet restoration efforts have met with uneven success, often due to lack of knowledge about habitat availability and use. Using habitat surveys and radio tracking of adult anadromous alewives Alosa pseudoharengus during their spring spawning migration, we illustrate a method for quantifying habitat using multiple approaches and for relating mobile fish distribution to habitat. In the Ipswich River, Massachusetts, measuring habitat units and physical conditions at transects (width, depth, and velocity) provided an ecological basis for the interpretation of landscape patterns of fish distribution. Mapping habitat units allowed us to efficiently census habitat relevant to alewives for the entire 20.6 river kilometers of interest. Our transect data reinforced the results of the habitat unit survey and provided useful, high‐resolution ecological data for restoration efforts. Tagged alewives spent little time in riffle–run habitats and substantial time in pools, although the locations of pool occupancy varied. The insights we provide here can be used to (1) identify preferred habitats into which anadromous fish can be reintroduced in order to maximize fish survival and reproduction and (2) pinpoint habitat types in urgent need of protection or restoration.Received April 3, 2011; accepted January 9, 2012

Highlights

After centuries of disturbance, environmental professionals recognize the need to restore coastal watersheds for native fish and protect the larger ecosystems on which fish and other aquatic biota depend
In the eastern United States, river herring are currently under review to be listed as threatened under the Endangered Species Act (NOAA NMFS 2011), and a recently filed lawsuit has charged management organizations with failing to take adequate measures to stem fish declines (Earthjustice 2010)
Upstream migration is reported to begin at temperatures between 5◦C and 10◦C (Loesch 1987), little instream movement occurs below 8◦C or over 18◦C (Collette and KleinMacPhee 2002), and spawning ceases at water temperatures exceeding 27◦C (Kissil 1974)

Summary

Introduction

Environmental professionals recognize the need to restore coastal watersheds for native fish and protect the larger ecosystems on which fish and other aquatic biota depend. Many of the recent (post 1982) references for physical habitat used by adult alewives in freshwater are reviews (Pardue 1983; Mullen et al 1986; Loesch 1987; Collette and Klein-MacPhee 2002; Table 1) In both reviews and original research reports, adult alewives spawn in ponds associated with coastal systems or in pond-like areas within coastal rivers and streams (Pardue 1983; Mullen et al 1986; Loesch 1987; Collette and Klein-MacPhee 2002; Walsh et al 2005). The limited number of recent original field investigations of alewife habitat in freshwater and the very general insights they provide, despite consistent and intense recent interest in these fish, partially reflect the logistical difficulty of studying habitat availability and use by these highly mobile fish

Methods

Results

Conclusion