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Effects of altered salinity on California Grunion embryos during beach incubation

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Effects of altered salinity on California Grunion embryos during beach incubation

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    1. Effects of altered salinity on California Grunion embryos during beach incubation Karen L. Martin, Juli K. Matsumoto, and Cassadie Moravek Pepperdine University Dept. of Biology 24255 Pacific Coast Highway, Malibu CA 900263-4321

    2. Sandy beaches are Essential Fish Habitat for California Grunion Leuresthes tenuis

    3. Spawning and early development are synchronized with the tides.

    4. Out of water, grunion embryos may encounter osmotic challenges: dilution by rainfall or dilution by freshwater runoff, or tidal excursions and wave wash hypersalinity from evaporation hypersalinity from human activities

    5. Desalination plants planned for coastal California will discharge concentrated brine

    6. This prototype was on the beach in Long Beach in the intertidal zone

    7. Long Beach grunion run

    8. METHODS: aquarium water and Coralife Scientific Grade Marine Salt for five treatment salinities Control salinity, 32 + 1 ppt (100%) 16 + 1 ppt (50%) 24 + 1 ppt (75%) 40 + 1 ppt (125%) 48 + 1 ppt (150%)

    9. Eggs were collected from Leo Carrillo State Beach (34 o 01N, 118o56W), Broad Beach (34 o 01N, 118o51W), Will Rogers Beach at Sunset Boulevard (34 o 02N, 118o33W), and Will Rogers Beach at Chautauqua Boulevard (34 o 01N, 118o31W),

    10. One group was fertilized in vitro at treatment salinities. Another group was collected 12 hours after natural fertilization. For the three State Beach sites, five replicates contained 200 eggs each in five salinities, a total of 3000 embryos. For Broad Beach, five replicates of 20 eggs for each salinity, for a total of 500 embryos. no effect of collection site on results Grunion eggs in situ Photo by M. Walton/ Grunion.org

    11. Effects of altered salinity initiated 12 hours post-fertilization: hatching %

    12. California Grunion Hatching Assessment: Instant Fish!

    13. Effects of altered salinity initiated during fertilization: fertilization %

    14. Effects of altered salinity initiated during fertilization: survival at 1.5 dpf

    15. Effects of altered salinity initiated during fertilization: hatching % of survivors

    16. Cumulative effects on survival

    17. Total effects on survival to hatching for in vitro fertilized eggs Lower fertilization % in low salinity. Lower survival to neurulation at low or high salinity. Lower hatching % at low and high salinities. Cumulative effects: significant losses at lower or higher salinities than normal.

    18. Larval length decreased with hypersaline incubation

    19. Distinct morphological deformities of the California Grunion embryo

    20. Altered sand salinity reduces viability Cumulative effects of altered salinity on early life history significantly decrease total survival to hatching. Salinities below 10 ppt and above 50 ppt are lethal to California Grunion embryos.

    21. Effects of altered salinity include: reduced fertilization, early embryo mortality, deformities, lower hatching success, smaller hatchlings, Result: significantly lower survival

    22. Coastal management should strive to avoid potentially serious negative effects of altered salinity on the California Grunions beach nursery grounds.

    24. REFERENCE: Matsumoto, J. K., and K. L. M. Martin. 2008. Lethal and sublethal effects of altered sand salinity on embryos of beach-spawning California Grunion. Copeia 2008: 483-490.

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