Dariusz P. Fey
Sea Fisheries Institute, Kołłątaja 1, 81-332 Gdynia, Poland
Key words: Shrinkage, herring, smelt, length correction.
Abstract.
The most significant changes in the length of larval and juvenile herring and
smelt occurred after two days of preservation in 4% formaldehyde seawater solution.
The larvae were then transferred to 96% alcohol, this was followed by additional
shrinkage over the next eight days. The subsequent 90 days of preservation did
not induce significant shrinkage. There were no differences in shrinkage between
smelt and herring and the degree of shrinkage for both species was very much
dependent on fish size, i.e. smaller specimens shrunk more (e.g. 12 mm SL:
8-18%) than larger ones (e.g. 28 mm SL: 0-2%). The live length of larvae
and juveniles that were initially preserved in formalin and then transferred
into alcohol can be back-calculated using an equation that describes the relationship
between SL measured prior to and after 10 days of preservation (SLlive=
0.910 SLpreserved + 2.695; n = 154, R2 =
0.994). This equation can be used for length correction of fish not larger than
30 mm in size when shrinkage is zero.