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Fish Habitat and Otolith Chemistry

Fish Habitat and Otolith Chemistry. By Nate Bickford and Brenda Norcross. Otolith Introduction. The location and identification of essential fish habitat has become a major focus of fisheries management. Traditional assessments of habitat use have relied on mark and recapture techniques.

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Fish Habitat and Otolith Chemistry

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  1. Fish Habitat and Otolith Chemistry By Nate Bickford and Brenda Norcross

  2. Otolith Introduction • The location and identification of essential fish habitat has become a major focus of fisheries management. • Traditional assessments of habitat use have relied on mark and recapture techniques. • Recently fisheries managers have used otolith chemistry to identify fish movement and habitat.

  3. Fish in Chukchi • Fish were collected during the Russian American Long Term Census of the Arctic (RUSALCA) Cruise • Bering Flounder (Hippoglossoides robustus) • BF is one of the most abundant flatfish in the Chukchi Sea.

  4. Methods • Fish were collected from 7 sites in the Chukchi Sea. • Otolith were removed and thin sectioned in a clean environment. • Chemical analyses were done by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS; otoliths; LSX-500). • We are looking for elemental differences between core (natal) and edge (where they were collected). • Elemental ratio we are concerned with are Sr/Ca Sr87/Sr86, Ba/Ca, and Mg/Ca.

  5. Bering Flounder were collected at sites – 13, 15, 18, 20, 23, 25, and 58

  6. Using a Quadratic Discriminant Analysis (QDA) different sites were grouped as water masses • Then I used the QDA to predict the membership in each water mass

  7. 72º 58 70º 20 18 23 WM1 68º 25 WM2 15 13 66º 6 180º 170º 160º • There are multiple stocks of Bering flounder in the Chukchi Sea. • Water mass 2 is essential for Bering Flounder in the Chukchi Sea • Why is the habitat in water mass 2 better

  8. Preliminary data • Gymnocanthus tricuspis, Arctic staghorn sculpin • Also collected during the RUSULCA cruise

  9. Arctic Staghorn Sculpin were collected at sites – 6, 11,13, 15, 17,18,20, 23, 25, 27, 58 62, 73, 85, 106, and 107

  10. Artic staghorn • Possible multiple groupings in three to four water masses • Next Step – discriminant statistics

  11. Acknowledgments • Funding • National Science Foundation • Sonja Bickford • Robyn Hannigan • Brenda Norcross • Chris Stark • Brenda Holliday • Matt Keyse • Fisheries Otolith Group (FOG) • Tom Weingartner • Seth Danielson

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