1. Nearshore fish communities response to habitat variability Terril P. Efird School of Fisheries and Ocean Sciences University of Alaska Fairbanks

2. Spatial distribution Fish spatially distribute based on habitat preference Within a given habitat fish composition, size and abundance vary Two factors – Kelp forest size – Kelp composition

3. Thesis Objectives: Determine how fish communities vary with kelp forest size Determine how fish communities vary with variation in kelp species composition Parameters measured: Fish composition and density Fish total length (TL) Kelp species composition and density Kelp forest size

4. Thesis progress Summer 2008 – Field work Proof of concept Proof of methods Fall 2008 – Data Analysis Winter 2009 – Presented as a poster at the Kachemak Bay Science Conference

5. Size distribution of Pacific Cod, Gadus macrocephalus, in kelp forests of Kachemak Bay, Alaska

6. Domestic longline, trawl, and pot fishery (Thompson & Dorn 2005) $150 million/year (ADFG 2008) Structure communities (Livingston 1989) Trophic link to SSL (Merrick 1997) Background: Pacific Cod

7. Intertidal & shallow subtidal as juveniles Oceanic as adults Use kelp forest during transition – Predator refuge – Foraging High relative abundance

8. Background: Kelp Forests Heterogeneous – Size – Understory abundance – Rugosity

9. Background: Kelp Forests Temporal variability – Annual species (O’Clair & Linstrom 2000) – Kelp forest shrinking (Estes et al 2004) – Forest forming species shift (Dames & Moore 1976)

10. Objective and Hypotheses Objective – To determine how G. macrocephalus stratify spatially throughout kelp habitats based on fish total length (TL) and habitat characteristics. Hypotheses – G. macrocephalus TL will positively correlate with increasing kelp forest size. – G. macrocephalus TL will negatively correlate with increasing understory abundance. – G. macrocephalus TL will negatively correlate with increasing habitat rugosity.

11. Methods Southern Kachemak Bay Four sites Fish and habitat surveys 3 surveys per site Outside Hesketh Inside Hesketh Sauna South Yukon 500 m

12. Fish Surveys Visual Transects – 30mx2mx2m Benthic & midwater All G. macrocephalus counted and sized Bodkin 1988

13. Benthic Habitat Surveys Data collected on benthic line Understory abundance est. with ¼ m quads Rugosity measures taken with PVC bar and chain Bodkin 1988

14. Surface Habitat Surveys Forest size was measured at slack low tide A small boat traced the outline of the forest canopy GPS track lines were then downloaded and the area calculated

15. Results: Forest Size

16. Results Hypotheses – G. macrocephalus TL will positively correlate with increase in kelp forest size. – G. macrocephalus TL will negatively correlate with increase in understory abundance. – G. macrocephalus TL will negatively correlate with increase in habitat rugosity.

17. Results: Understory Abundance

18. Results Hypotheses – G. macrocephalus TL will positively correlate with increase in kelp forest size. – G. macrocephalus TL will negatively correlate with increase in understory abundance. – G. macrocephalus TL will negatively correlate with increase in habitat rugosity.

19. Results: Rugosity

20. Results Hypotheses – G. macrocephalus TL will positively correlate with increase in kelp forest size. – G. macrocephalus TL will negatively correlate with increase in understory abundance. – G. macrocephalus TL will negatively correlate with increase in habitat rugosity. No but…

21. Results: Rugosity

22. Conclusions Bigger fish were found in bigger forests Smaller fish were found in areas with greater cover Rugosity?

23. What’s next? Kachemak Bay – July 2009 – All fish species – 20 sites – Wide range of forest sizes

24. What’s next? Aleutian Islands – June 2009 & 2010 – All fish species – Address generality – 2 kelp species

25. Thank You Funding Rasmuson Fisheries Research Center Advisor Dr. Brenda Konar Logistics Nathan Stewart and Patrick Lane Hans and Leila Pederson Institutional Support

26. Questions? References: Alaska Department of Fish and Game. 2008. Pacific Cod fisheries in Alaska. http://www.cf.adfg.state.ak.us/geninfo/finfish/grndfish/pcod/pcodhome.php http://www.cf.adfg.state.ak.us/geninfo/finfish/grndfish/pcod/pcodhome.php Livingston PA. 1989. Interannual trends in Pacific Cod, Gadus macrocephalus, predation on three commercially important crab species in the eastern Bering Sea. Fishery Bulletin. Vol 87(4): 807-827 Merrick RL, MK Chumbley and GV Byrd. 1997. Diet diversity of Steller sea lions (Eumetopias jubatus) and their population decline in Alaska: a potential relationship. Canadian Journal of Fisheries and Aquatic Sciences. 54: 1342-1348 Thompson GG and MW Dorn. 2005. Assessment of the Pacific Cod stock in the Gulf of Alaska. Executive summary, National Marine Fisheries Service, National Oceanographic and Atmospheric Administration.