Criteria for determining maturity stage in female American shad, Alosa sapidissima, and a proposed reproductive cycle.

MD Arendt
JA Lucy
TA Munroe

Abstract

Ultrasonic transmitters were surgically implanted into adult tautog (n=27,400-514 mm TL) to document seasonal occurrence and site utilization at four sites situated within known tautog habitat near Cape Charles, Virginia, in lower Chesapeake Bay. Tagged tautog were released at the same sites where originally caught within 2 h of capture. Sites were continuously monitored with automated acoustic receivers between 9 November 1998 and 13 October 1999. Two sites consisted of natural bedform. materials and two sites consisted of manmade materials. Ninety-four percent of tautog (n=15) released in fall 1998 remained inshore during winter at sustained water temperatures of 5-8 degreesC, rather than moved offshore during winter as documented for tautog off New York, Rhode Island, and Massachusetts. Ninety-one percent (n=10) of tautog released in spring 1999 remained inshore during summer when water temperature was 27 degreesC and in the absence of an important food item, blue mussels (Mytilus edulis). These findings conflict with assertions that tautog move to cooler water in summer when water temperatures reach 20 degreesC. Tautog released at natural bedform. sites were detected only at these sites throughout the study. Tautog released at manmade structures also displayed high site-utilization patterns, but several tautog periodically moved 2-10.2 km away from these sites over featureless bottom, a known deterrent to emigration for large temperate labrids in other waters. Benthic communities were similar at manmade sites and natural bedform sites, and movement away from manmade sites may have been influenced by habitat size as well as habitat structure. Understanding temporal and spatial utilization of habitats is an important first step to identifying essential fish habitat and to evaluating and protecting fishery resources within Chesapeake Bay and elsewhere.