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Migration of Atlantic Salmon Postsmolts in Relation to Habitat Use in a Coastal System
Author(s) -
Lacroix Gilles L.,
McCurdy Paul,
Knox Derek
Publication year - 2004
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/t03-032.1
Subject(s) - bay , estuary , salmo , fishery , fish migration , clupea , herring , range (aeronautics) , oceanography , habitat , predation , environmental science , geography , fish <actinopterygii> , biology , ecology , geology , materials science , composite material
Acoustic telemetry was used to monitor the early marine migration of Atlantic salmon Salmo salar from two rivers of Passamaquoddy Bay, a coastal system with numerous Atlantic salmon farms and weirs for Atlantic herring Clupea harengus on the border of Canada and the United States. Monitoring at fixed sites, active tracking, and systematic searches for tagged fish were combined. The migration success of hatchery‐reared ( N = 96) and wild ( N = 38) smolts out of the estuaries was high (range, 90–97%), and the overall success of postsmolts moving out of Passamaquoddy Bay and into the several passages leading to the Bay of Fundy was reasonable (range, 71–88%). Estuary transit times were usually rapid (<36 h), and almost all smolts entered the bay during an ebb tide. Migration routes through Passamaquoddy Bay were then closely related to the counterclockwise residual surface current in this bay. Routes differed among groups monitored, and they influenced the location of exit from the bay. The majority of postsmolts moved quickly through the bay (2–6 d) and left by a direct route (range, 74–85%), usually during an ebb tide. Postsmolts that were slow to leave (maximum, 12 d) moved across the bay from the head of one passage to another. The presence of salmon farms both in the estuary and along the migration route of fish from one of the rivers did not delay migration, but most losses of smolts and postsmolts from that river occurred in areas near the salmon farms where potential predators were abundant. Herring weirs in the bay entrapped and delayed some postsmolts from both rivers, and they caused a few losses when postsmolts failed to exit.