Faunal Community Use of Enhanced and Natural Oyster Reefs in Delaware Bay

Transcription

1 Faunal Community Use of Enhanced and Natural Oyster Reefs in Delaware Bay Jenny Paterno Graduate Program in Ecology & Evolution Haskin Shellfish Research Laboratory Rutgers, The State University of New Jersey

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3 Est Photo credits: Lisa Calvo

4 My Question: Does the Project PORTS enhancement effort alter species abundances and community assemblages relative to unenhanced (natural) bottom? Hypothesis: Adding spat on shell to sub-tidal bay bottom over time, will result in a faunal community similar to natural oyster reefs.

5 Objectives for field study: 1. sample fishes and invertebrates on a restoration area and nearby unenhanced bottoms 2. compare species assemblages across different bottom types Photo credit: M. Luckenbach, VIMS 3. make conclusions about restoration efforts

6 Each of the 7 study sites are: 300 m x 115 m m km acres The entire enhancement area : 4.05 hectacre m km 2 10 acres

7 Methods Otter trawling: transient and resident fishes Twice a month on each site July-November tows per site 30 tows/site over study duration Benthic habitat trays: resident fishes and macro-invertebrates 2 trays on each site once a month July-November week soak time 10 trays/site over study duration

8 Trawl monitoring

9 Benthic habitat trays Dimensions: 60 cm x 60 cm x 10 cm 12 quarts (~11.3 liters) of substrate put into each tray - collected using a lined dredge Collected: Faunal information (species, length, weight) Benthic habitat information Oyster abundance Box (dead oyster) abundance Cultch, debris (mud, sand, rock) and oyster volume

10 Bar graph of average count of oysters per tray across all seven sites. Data are means ± 1 SE from trays (0.36 m 2 x 9.5 cm, 11 liters of bottom material) n= 10 trays per site. Letters denote significant differences P 0.05, Tukey s HSD Average abundance of oysters per tray 60 a ab bc c c c c Number of oysters per tray HN26avg HN28avg GBOREA HS18avg Nant19avg St23avg St28avg H1 H2 High oyster density Site L1 L2 L3 L4 Low oyster density

11 Trawl A total of 1609 individuals of 30 species were collected in the trawl

12 Transient species Species Common Name H1 H2 GBOREA L1 L2 L3 L4 Total Anchoa mitchili bay anchovy Micropogonias undulatus Atlantic croaker Cynoscion regalis weakfish Trinectes maculatus hogchoker Callinectes sapidus blue crab Morone americana white perch Menticirrhus saxatilis northern kingfish Bairdiella chrysoura silver perch Leiostomus xanthurus spot Pogonias cromis black drum Limulus polyphemus horseshoe crab Paralichthys dentatus summer flounder Chilomycterus schoepfi striped burrfish Centropristis striata black sea bass Alosa pseudoharengus alewife Brevortia tyrannus Atlantic menhaden Morone saxatilis striped bass Ophidion marginatum striped cusk-eel Syngnathus fuscus northern pipefish Prionotus carolinus northern sea robin Peprilus triacanthus butterfish Mustelus canis smooth dogfish Libinia emarginata spider crab Astroscopus guttatus northern stargazer Malaclemys terrapin diamondback terrapin Penaeus aztecus brown shrimp Scophthalmus aquosus windowpane flounder Alosa mediocris hickory shad

13 Oyster reef resident species Species Common Name H1 H2 GBOREA L1 L2 L3 L4 Total Opsanus tau oyster toadfish Gobiosoma bosci naked goby In summary, abundances of these species were highest on: High oyster density GBOREA Low oyster density Pogonias cromis Morone americana Centropristis striata Trinectes maculatus Opsanus tau Menticirrhus saxatilis Chilomycterus schoepfi Morone saxatilis Micropogonias undulatus

14 Trawl: Species Accumulation Curves Cummulative Number of Species Collected Number of trawls HN H1 26 HN H2 28 GBOREA HS L1 18 Nant L2 19 St L3 23 St L4 28 Species accumulation curves of motile fauna for each sampling location. Solid lines are the Michaelis-Menten model curves fit to the data for each site.

15 Number of individuals per tow H1 H2 GB L1 L2 L3 L4 H1 H2 GB L1 L2 L3 L4

16 Principle Component Analysis on selected trawl data (19 species): rare species and those that wouldn t be adequately sampled with an otter trawl were not included PCA Axis 2 (eigenvalue = 0.17) TMacul MUndul CSapid PDenta LXanth MenSaxat CRegal CSchoe CStria BChrys OTau LPolyp MorSaxat PCarol SFuscs PTriac MCanis PCroms MAmerc PCA Axis 1 (eigenvalue = 0.34)

17 PCA Axis 2 (eigenvalue = 0.17) TMacul MUndul CSapid PDenta MenSaxat CSchoe LXanth CRegal CStria BChrys OTau LPolyp MorSaxat PCarol SFuscs PTriac PCroms MCanis MAmerc -1.0 PCA Axis 1 (eigenvalue = 0.34) 1.0 Species Samples July August September October November

18 Benthic Habitat Trays 2211 individuals of 19 species were collected in the trays

19 Transient species Species Common Name H1 H2 GBOREA L1 L2 L3 L4 Total Ilyanassa obsoleta eastern mudsnail Paleomonetes vulgaris marsh grass shrimp Paleomonetes pugio daggerblade grass shrimp Mulinia literalis dwarf surf clam Pagarus longicarpus long-clawed hermit crab Polinices duplicatus shark eye moon snail Tellina agilis northern dwarf tellin Crangon septemspinosa sand shrimp Anguilla rostata American eel Oyster reef residents Species Common Name H1 H2 GBOREA L1 L2 L3 L4 Total Panopeus herbstii Atlantic mud crab Rhithropanopeus harisii estuarine mud crab Panopeus sayi say mud crab Ischadium recurvum hooked mussel Gobiosoma bosci naked goby Geukensia demissa ribbed mussel Crepidula convexa slipper snail Opsanus tau oyster toadfish Urosalpinx cinerea Atlantic oyster drill Eurypanopeus depressus flat back mud crab

20 Trays: Species Accumulation Curves 14 Cumulative Number of Species Collected HN H1 26 HN H2 28 GBOREA HS L1 18 Nant L2 19 St L3 23 St L Number of Trays Species accumulation curves of motile fauna for each sampling location. Solid lines are the Michaelis-Menten model curves fit to the data for each site.

21 H1 H2 GB L1 L2 L3 L4 H1 H2 GB L1 L2 L3 L4

22 -1.0 Axis 2 (eigenvalue = 0.067) 1.0 CCA Biplot (species ~ habitat properties) CultVolm BoxCount OystCoun CConvex UCiner CSeptm GDemis DebrVolm EDeprs RHaris GBosciOTau PDuplc PSayiPPugio PHerbs PVulgr IRecurIObsol PLongc MLiter ARosta TAgilis -1.0 Axis 1 (eigenvalue = 0.085) 1.0 Canonical Correspondence Analysis (CCA) biplot of bottom habitat parameters (explanatory variables) and tray catch. Explanatory variables account for 11.0% of the variation exhibited in catch data. (P<0.005)

23 Using Simpson s Index of Diversity (SID) equation, indexes were calculated using cumulative trawl data from each of the seven sites. Excluding Anchoa mitchili, the ten most abundant species collected in the trawl were included in the calculations. The GBOREA exhibited the highest overall diversity index (0.845) of any other site. Simpson's Index of Diversity More diverse Less diverse Diversity Index (Range 0-1) H1 H2 GBOREA L1 L2 L3 L4 Site

24 Summary of Results Overall, a similar fish and macroinvertebrate community was found across all sites. The enhancement site exhibited the greatest cumulative diversity of fish species Species richness and total abundance: High oyster density reefs > Enhancement area Low oyster density reefs The enhancement area appears to represent a transitional stage between degraded oyster habitat and high oyster density habitat. In addition to its educational benefits, Project PORTS, a small-scale community based restoration program created valuable oyster habitat. Integration and Application Network, University of Maryland Center for Environmental Science

25 Conclusion The low relief oyster reef built through Project PORTS is supporting a diverse faunal community consistent with natural oyster habitats.

26 Acknowledgements Lisa Calvo, Rutgers University Program Coordinator Funding Dupont Clear into the Future Geraldine Dodge Foundation American Littoral Society NJ Sea Grant Advisor: David Bushek, Committee members: Thomas Grothues, Olaf Jensen and Rebecca Jordan Special thanks to my dedicated field crew: Iris Burt, Sarah Borsetti, Amy Danka, Jessica Horton and Jennifer Gius.