Movement patterns of American eels (Anguilla rostrata) between salt- and freshwater in a coastal watershed, based on otolith microchemistry

• Published in: Marine biology 2006-09, Vol.149 (6), p.1567-1576
• Main Authors: Lamson, Heather M, Shiao, Jen-Chieh, Iizuka, Yoshiyuki, Tzeng, Wann-Nian, Cairns, David K
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Anguilla rostrata; Animal and plant ecology; Animal behavior; Animal migration; Animal, plant and microbial ecology; Aquatic habitats; Bays; Biological and medical sciences; catadromous fish; eel; Fish; Fish ladders; Fresh water; freshwater; Freshwater environments; Fundamental and applied biological sciences. Psychology; habitat preferences; Habitat utilization; habitats; Marine; Marine biology; migratory behavior; otoliths; Ponds; Saline water; Salmonidae; Salts; Sea water ecosystems; Spillways; Strontium; Synecology; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Watersheds
• ISSN: 0025-3162; 1432-1793
• DOI: 10.1007/s00227-006-0308-2

Otolith strontium:calcium ratios were used to trace lifetime movements of American eels (Anguilla rostrata) captured in salt-water bays and adjoining freshwater ponds in Prince Edward Island, Canada. Eels were classified into migratory contingents based on their movement patterns. A pond with a pool-and-weir salmonid fishway and a pond drained by a low-gradient channel contained eels that had entered freshwater at all ages, but a pond with a 2.2 m vertical spillway contained only eels that had entered freshwater in the elver year. Salt-water residents were the dominant migratory contingent in salt-water bays (85% of 39), which overturns the paradigm of obligate catadromy for this species. Freshwater residency was the sole pattern found in the pond with the vertical spillway (100% of 12) and the majority contingent in the pond with the low-gradient channel (54% of 24). Inter-habitat shifting was the dominant migratory contingent in eels sampled from the pond with the pool-and-weir fishway (85% of 20). Resident eels were established in salt- and freshwater habitats by the year after their arrival in continental waters. Eels that shifted between habitats increased their rate of inter-habitat shifting with age. The high degree of plasticity in habitat use found in this study is consistent with worldwide Anguillid patterns as revealed by Sr:Ca.