Hands on with Invasive Species
by Nicole Carlozo -- August 27th, 2012
There’s nothing like a day on the water, especially when you’re getting your hands dirty (or in this case, slimy and scaly) in the brackish waters of Maryland’s Chesapeake Bay.
When I first graduated from college, I spent my summer sampling fish and invertebrate species with the Smithsonian Environmental Research Center (SERC). After a summer of intense field work, I wondered if those skills would ever come in handy again. It turns out, they did.
I was recently recruited to aid the Chesapeake Bay’s volunteer program within the National Estuary Research Reserve system. 6,249 acres are preserved within Maryland’s Chesapeake Bay at three different locations for research and education purposes.
We arrived early at Otter Point Creek to meet with some veteran volunteers and prepare for the day’s activities: seining and trawling. The Bush river sites are sampled 6 times per summer with the help of local volunteers and a few DNR staff.
Nostalgia overwhelmed me as I climbed into the crowded 14-foot jon boat and headed out on the Chesapeake for fish sampling and identification. As the morning proceeded, I brushed out the cobwebs in the recesses of my brain and found that my previous fish identification knowledge was still intact. Happy day.
While I easily identified the white perch, yellow perch, rockfish, catfish, spot, anchovies, silversides, pumpkinseed, American eels, and other assorted fishes, there were a few invasive species that caught my eye. Have you come across these fish?
Invasive Species of the Week: Causing mischief in our Bay
On our second trawl of the day, I tentatively took my turn tying the end of the trawl net and throwing it overboard. 10 minutes later, we drew in the net to find 2 very large carp splashing among our catch. These guys are native to Eastern Asia, but they’re currently breeding in all tributaries of the Bay.
Managers originally introduced common carp into ponds as a food source through the US Fish Commission. Over time, accidental releases led to breeding populations that have significantly impacted native species. These fish influence habitat and food web dynamics through herbivory, predation, and bioturbation (increasing water turbidity during feeding by disturbing sediment). They have been blamed for declining native fisheries.
Goldfish (Carassius auratus)
Imagine my surprise when we hauled in our trawl net and I noticed a large goldfish (about 10 inches in length) among our catch. Although goldfish are native to China, Korea, and Eurasia, they’ve been living in the Chesapeake since the 1890s. They may not be as widespread as the common carp, but their presence still has potential negative impacts. Competition with other prey species, herbivory, and bioturbation are among their faults.
Visit SERC’s invasive database for more information.