Potential Impact of Herbivorous Fish on Ulva Bloom Biomass

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1 University of Rhode Island Senior Honors Projects Honors Program at the University of Rhode Island 2012 Potential Impact of Herbivorous Fish on Ulva Bloom Biomass Tanja Schollmeier University of Rhode Island, Follow this and additional works at: Part of the Marine Biology Commons Recommended Citation Schollmeier, Tanja, "Potential Impact of Herbivorous Fish on Ulva Bloom Biomass" (2012). Senior Honors Projects. Paper This Article is brought to you for free and open access by the Honors Program at the University of Rhode Island at It has been accepted for inclusion in Senior Honors Projects by an authorized administrator of For more information, please contact

2 Potential Impact of Herbivorous Fish on Ulva Bloom Biomass Tanja Schollmeier Project sponsor: Carol Thornber

3 Overview 1. Proposed Research Question 2. Background: Ulva spp. 3. Background: Fundulus spp. 4. Methods 5. Results: Seining 6. Results: Gut content analysis 7. Results: Paired-choice feeding assays 8. Conclusion 9. Future research

4 Proposed Research Question Do Fundulus heteroclitus and/or Fundulus majalis consume Ulva bloom biomass and if so is there a preference between Ulva rigida and Ulva compressa?

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6 Background: Ulva spp. Eutrophication = nutrient enrichment Macroalgae blooms Common bloom species include Ulva compressa and U. rigida

7 Background: Ulva spp. cont. Effects of algae blooms: Interference with fishing and sailing Beach fouling Decreased coastal biodiversity Contributes to hypoxic events Produces toxic chemicals

8 Background: Fundulus spp. Abundant in salt marshes High tide F. heteroclitus and F.majalis are the two abundant Fundulus species in RI Studies yielded different results for Fundulus spp. diet Seem to be opportunistic feeders

9 Methods Monthly surveys 2 sites July April 2012 Identification and quantification of species

10 Methods cont. Species collected for gut content December 2011 April 2012 Humanely euthanized Dissection same day as collection Paired-choice feeding assays with F. majalis

11 Results: Seining Most abundant animal species: Menidia menidia Palaemonetes spp. Fundulus spp.

12 Results: Gut content analysis Size range: cm Gut fullness varied each month F. majalis Copepods Ostracods F. heteroclitus Prorocentrum spp. Ostracod Prorocentrum Copepod

13 Results: Paired-choice feeding assays 13 replicates Comparison of final versus initial wet mass of the two species of Ulva U. compressa: no change U. rigida: increased algae mass Not significant

14 Conclusion Our results suggest that: F. majalis Carnivorous Possible positive effect on U. rigida No effect on U. compressa F. heteroclitus Herbivorous Possible effect on Ulva bloom biomass

15 Future Research Paired-choice feeding assays of F. heteroclitus starting in May Continued seining Continued gut content analysis Comparison of high tide and low tide Seining Gut content analysis

16 Acknowledgements Project Sponsor: Carol Thornber Thank you also to: Michele Guidone Emily Bishop Shelby Rinehart Melissa Wands Amanda Ziegler Funding Sources: URI Honors Program Stan Cobb Marine Biology Fund URI Undergraduate Research Initiative

17 References Hauxwell, J. et al Macroalgal canopies contribute to eelgrass (Zostera marina) decline in temperate estuarine ecosystems. Ecology 82: James-Pirri, M.J., Raposa, K.B., Catena, J.G Diet composition of mummichogs, Fundulus heteroclitus, from restoring and unrestricted regions of a New Endland (U.S.A.) salt marsh. Estuarine, Coastal and Shelf Science 53: Kneib, R.T The role of Fundulus heteroclitus in salt marsh trophic dynamics. Amer. Zool. 26: Nelson, T.A., Lee, D.J., Smith, B.C Are green tides harmful algal blooms? Toxic properties of water-soluble extracts from two bloom-forming macroalgae, Ulva fenestrate and Ulvaria obscura (Ulvophyceae). J. Phycol. 39: Nixon, S. W Coastal marine eutrophication: A definition, social causes, and future concerns. Ophelia 41: Rosenberg, R Eutrophication-The future marine coastal nuisance. Mar. Pollut. Bull. 16: Taylor, R The growth of selected green tide algae in laboratory culture effects of irradiance, temperature, salinity and nutrients on growth rate. Bot. 44: Thomsen, M.S., McGlathery, K Effects of accumulations of sediments and drift algae on recruitment of sessile organisms associated with oyster reefs. Exp. Mar. Biol. Ecol. 328: Valiela, I Macroalgal blooms in shallow estuaries: Controls and ecophysiological and ecosystem consequences. Limnol. Oceanog. 42:

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