Fin development in stream- and hatchery-reared Atlantic salmon

Abstract

To determine the effect of development and environment on fin growth, we measured fin lengths of juvenile Atlantic salmon (Salmo salar) from two hatcheries (August, October and April -May), stream-reared fish (July and October) stocked as fry into two tributaries, and smolts from the main stem of the Connecticut River (May). For stream-reared parr, there was a linear relationship between the dorsal, caudal and anal fins with fork length, while the pectoral, pelvic and adipose fins exhibited a curvilinear relationship with fork length. Parr from a high gradient stream had larger caudal fins than fish from a low gradient stream, but other fins did not differ. Regression lines for the fins of stream-reared smolts were all linear when fin length was regressed against fork length. Stream-reared parr had larger pectoral, pelvic and anal fins than smolts of similar size while dorsal and caudal fin lengths did not differ. Regression equations formulated using the fins of stream-reared parr were used to calculate the percent difference (100 Â observed fin length/expected) in fin lengths between stream-and hatchery-reared parr. The pelvic, adipose, caudal and anal fins of hatchery-reared parr showed no signs of degeneration by the first sampling period 7 months after hatching, whereas degeneration in the pectoral (13 -20%) and dorsal (15 -18%) fins was evident at this time. By the end of the study, degeneration was present in every fin except the adipose, with the pectoral (35 -65%) and dorsal (32 -58%) fins exhibiting the greatest amount of fin loss. All fins of hatchery-reared parr became shorter with time. There were minor differences in fin degeneration among parr from the two hatcheries, but the overall pattern of decreasing fin size was similar, indicating a common cause of fin degeneration. Comparison of stream-and hatchery-reared fish is a valuable means of determining the impact of captive environments on fin growth. Published by Elsevier Science B.V.

Salmon Welfare Index Model (SWIM 1.0): a semantic model for overall welfare assessment of caged Atlantic salmon: review of the selected welfare indicators and model presentation

“…2007). The fins fulfil important functions in both locomotion and intraspecific communication in salmonids (Abbott & Dill 1985; Pelis & McCormick 2003) and severe fin erosion thus has the potential to affect behaviour. However, the evidence is scarce or contradictory, and any functional impairment following fin erosion has yet to be demonstrated scientifically.…”

Cultured Atlantic salmon in nature: a review of their ecology and interaction with wild fish

“…Hjort and Schreck, 1982;Fleming and Gross, 1989;Swain et al, 1991;Fleming et al, 1994;Pelis and McCormick, 2003;Kostow, 2004;von Cramon-Taubadel et al, 2005). Because juvenile mortality in nature is very high but most fish may survive in a hatchery, the distribution of wild juvenile phenotypes should be a subset of cultured juvenile phenotypes.…”

Effects of temperature, stocking density and farming conditions on fin damage in European sea bass (Dicentrarchuslabrax)

“…Because fin profile changes are visible and potentially easy to quantify, fin condition has long been considered as a useful indicator of fish health status. For re-stocking programs, relative fin length is commonly used as an indicator of juvenile quality as it is highly affected by rearing conditions such as substrate, temperature, water quality, feeding and water velocity (Wagner et al 1996;Winfree et al 1998;Barrows and Lellis 1999;Arndt et al 2002;Pelis and McCormick 2003;Ellis et al 2009). The pathology of fin erosion has been described in many species and sometimes using other organismic indices; fin injuries are commonly used to score fish health condition on farms (Goede and Barton 1990; Turnbull et al 1996;Latremouille 2003;St-Hilaire et al 2006).…”