LE3 .A278 2013

2013

Avery, Trevor

Acadia University

Bachelor of Science

Honours

Biology

Biology

In 2009, the IUCN Red List of Threatened Species designated Little skate as near threatened and Winter skate as endangered. While the western Scotian Shelf-Bay of Fundy population has been deemed stable, no study has ever been performed past Cape Chignecto into the inner Bay of Fundy. Little and Winter skate are both sympatric and morphologically similar, causing extreme difficulties in identification of live species. Winter skate may be identified through ocelli, which, when present, are usually found in abundance of 2-8. Winter skate also achieve greater lengths than Little skate, who grow to a maximum total length of 54 cm. This capture-mark-recapture study was performed at a herring weir in Bramber, NS, Canada, for 6 weeks in July – September of 2012. A total of 512 skates were measured, with 176 tagged, and 276 fin clips taken. Five recaptures were found, which produced a Schnabel population estimate of 7,353 individuals, with a confidence interval of 3,663 to 16,084 skates. Fin clips were used for genetic identification, which was accomplished through restriction fragment length polymorphism and sequencing. Of the 46 samples sequenced, 4 proved to be Little skate, and 42 Winter skate. One of the sequenced Little skates was measured as 60 cm TL, greater than the maximum length previously assumed for Little skate. Two Winter skates were found with > 8 ocelli, the reported maximum. One Little skate and 5 Winter skates were found with claspers at lengths smaller than the reported minimum length for development of claspers. The occurrence of these traits outside the respective boundaries set by the current identification guide highlight the need for future research into Little and Winter skate if conservation and management in the Canadian Atlantic are to be pursued

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https://scholar.acadiau.ca/islandora/object/theses:1001