Stories from the Bay
We gathered on Friday, Aug. 14, to see if anything had taken up residence on the reef we built off south Reed's Beach. Leading the first round of oyster abundance and biodiversity sampling was Dr. Christine Thompson, restoration scientist for the American Littoral Society. She met the restoration team during the outgoing tide, when the reef would be almost fully exposed.
The reef was created in April 2015 during our Shell-A-Bration. With the help of 140 volunteers, in partnership with Conserve Wildlife Foundation, tons of bagged whelk shell were used to build an inter-tidal reef. The reef was intended to serve several purposes, not least of which was to provide a natural habitat for oysters. It was also hoped that the reef would help reduce wave erosion of the beach, which had been restored by the society for horseshoe crabs and shorebirds following the devastating effects of Hurricane Sandy.
Several randomly selected bags of whelk shell were pulled from sections of the reef and taken to the beach for further analysis. There we broke out the calipers and identification guides to see what -- if anything --was living on our oyster reef. It quickly became evident that the unique shape of the whelk shell made it a great starter home for all sorts of smaller creatures, including juvenile fish. Ribbed mussels (Geukensia demissa), grass shrimp (Palaemonetes pugio), black and white fingered mud crabs (Panopeus herbstii, Rhithropanopeus harrisii), green crabs (Carcinus maenas), mud dog whelks (Ilyassoma obsolete), skilletfish (Gobiesox strumosus), and a variety of polychetes (Polychaeta) were found in and around the whelk shells. Encrusted on and inside the shells were barnacles (Cirripedia), bryozoans (Bryozoa), sea grapes (Molgula), slipper shells (Crepidula fornicata), and amphipods (Amphipoda).
Perhaps most important, we found baby oysters -- also known as spat. Many of the shells that were sampled had oyster spat ranging in size from 2mm-30mm. Once the creatures were identified, they -- along with their homes -- were returned to the Bay.
We plan to come back in two weeks to take another look at our marine-life condo complex on Delaware Bay. This was the first of six sampling events, which will be conducted through October.
By Captain Al Modjeski and Shane Godshall, American Littoral Society
It was clear, sunny, and 90+ degrees Monday and Tuesday when we began our first of ten fish monitoring survey events at the South Reeds Beach experimental oyster reef. The reef was constructed in April 2015 by over 140 volunteers during our “Shell-a-Bration", an event held in partnership with Conserve Wildlife Foundation.
Through the haze and the chop, we launched the American Littoral Society’s survey boat, the R/V Great Auk, from Smokey’s Marina in North Reeds Beach and headed towards the survey site. Thank goodness there was some wind to cool us off and keep the greenheads at bay. On the way out, we saw numerous shorebirds and witnessed the explosive nature of bluefish feeding on a number of schools of menhaden (bunker).
At the site, we placed nine un-baited fish traps at three pre-determined, randomly chosen stations on and adjacent to the inshore and offshore reefs to evaluate fish use during the incoming and outgoing tide as well as over a 24 hour period (tide dependent). Traps were placed on top and alongside reef segments and a control site was surveyed that consisted of a similar bottom type that existed before the reef was built. The semi-oval, collapsible traps had funnel-shaped openings on both ends that allowed fish to enter but inhibited exit. For this event, traps were deployed from the boat during the incoming tide. Inshore traps were collected after a 5 hour soak time and the remaining traps were retrieved after 24 hours. Once retrieved, the living contents of each trap were processed on-site and species, weight, and length were recorded. All species were released after processing.
Our first round of sampling gave us some great results. For the inshore traps retrieved after a five hour soak time, we trapped two scup, (Stenotomus chrysops), several mud crabs, and few juvenile blue crab. The scup were captured on the inshore side of the reef segment. Traps set on top of the reef mostly contained hermit crabs, comb jellies, and mud dog whelks. At the sandy bottom control site to the south of the reef, we processed several Jimmy #1 blue crabs but did not trap any fish or have enough for crab cakes.
The big news from our first round of sampling came from our offshore reef traps. We retrieved the three offshore reef traps 24 hours after deployment and as the traps were pulled aboard, we initially saw what appeared to be two juvenile weakfish (Cynoscion regalis)! - which would be great since the weakfish population in the bay crashed many years ago - but upon further examination, it was determined that our yellow-finned friends were actually another estuarine resident, the silver perch (Bairdiella chrysoura). We also processed up a number of mud dog whelks, hermit crabs, mud crabs, and grass shrimp. Overall, it was a good start to our sampling program and initial results would indicate that the reef is being used by juvenile species for foraging and shelter.
We'll be heading back out every two weeks through November to conduct the fish surveys, so stay tuned for updates.