Teeny Weenie Fish Found in Sandy Hook Bay

Written by Joe Reynolds Tuesday, 30 June 2009 09:06

Columns - Old Oak Trail

It was the first full weekend of summer and the weather was beautiful. I think it was the first weekend without a rainstorm in nearly three weeks.

Saturday dawned bright and sunny. By mid-day the sun was still shining, the sky was blue, and a gentle breeze was tickling the leaves of the trees.  It felt real good to see blue sky and sunshine again for an entire day.

Near the mouth of Many Mind Creek (a beach I like to call Bivalve Beach since there are so many different mollusks to discover) in the heart of Sandy Hook Bay, I was surveying the estuarine waters on behalf of the Bayshore Regional Watershed Council. The site is located downstream from where the Hudson River empties into Lower New York Bay. Fresh waters from Middletown and Atlantic Highlands mix here with saltwater from the sea and brackish waters from other parts of the estuary via two high tides and two low tides almost every single day.

(The smile of a young Oyster Toadfish looks nasty, but unless you are a crustacean most people have nothing to fear from this interesting and abundant fish in Sandy Hook Bay)

Sandy Hook Bay was calm and warm, with water temperatures in the mid 70s. Turbidity was relatively clear despite stormy weather the night before, but the density of Sea Lettuce seemed to expand as I stood there. The salinity near the mouth of Many Mind Creek was salty at around 28 ppt, but this seemed natural since the bay's salinity is highest near its mouth where sea water from the Atlantic Ocean enters.

(A juvenile pipefish. Pipefishes are related to seahorses, notice the similar face features)

As I concluded my chemical and physical tests, a few other volunteer members from watershed council joined me on the beach. We had planned earlier to continue testing the wellbeing of Sandy Hook Bay. Out method of testing, however, would be using a seine net to conducting a biological study of the bay.

(A young Scup recently found in Sandy Hook bay)

I've always considered these brief seining encounters along a small shallow section of the bay special moments. It was as if I were taking the pulse of the overall estuary. If I find a lot of aquatic critters in this tiny area of the bay in a short period of time, then I can only imagine what might exist in deeper and wider areas of the estuary. All of us were eager to see what we could catch in our seine net.

A seine is a net and still commonly used by scientists to find out cheaply and quickly the diversity of fish living in waist deep areas of a water body. They are an excellent tool for collecting aquatic animals with minimal injury to the catch. A seine net is generally made of tight mesh with a float seamline on top, and a lead seamline on the bottom.

It was late morning by the time we had out seining gear ready and in place. We made three hauls of our 50' long and 4' high seine on a rising tide and an unexpected current moving easterly along the coast. We caught 10 species of fish, Lady Crabs, Mud Crabs, Hermit Crabs, and Sand Shrimp.

(The Bay Anchovy is a small, but common fish this year in Sandy Hook Bay that eats mainly plankton)

Each haul our net came ashore pulsing with small fish, many of which were little Bay Anchovies, Rough Silversides, Striped Killifish, and young-of-the-year [yoy] Menhaden and Bluefish. There were also many Pipe fish, young Oyster toadfish, young Windowpane flatfish, and a young Scup.

By far, the most popular catch of the day was finding three young-of-the-year Winter Flounders within the drift algae. These charming, little flatfish were most likely produced during last winter or spring by adults spawning in the nearshore estuarine waters of the bay.  Larvae are initially planktonic but metamorphosis (when the left eye migrates to the right side of the body and the larvae become "flounder-like") begins around 5 to 6 weeks after hatching, and is completed by about 8 weeks after hatching. Young-of-the-year Winter Flounder take up residence in shallow water where they may grow to about 3 to 4 inches within the first year.

(A first-of-the-year Winter Flounder recently found in a seine net in Sandy Hook Bay)

Although studies continue to learn more about juvenile Winter Flounder, it has recently been discovered by investigations up the Hudson River that many first year fish eat plankton, especially Copepods. As they increased in size, their diet changed as well to larger estuarine critters, such as tiny worms and amphipods. No doubt, the health of Winter Flounder populations depends greatly on the health of their estuarine home.

Just when you think you know the estuary well, there is a surprise in your seine net that catches you off guard. Who knew that this modest section of the estuary is perhaps an important area for juvenile Winter Flounder to mature?

If accurate, this means that there is a greater need for local residents to protect this coastal environment for the wellbeing of Winter Flounder in the estuary. Studies in Maine have shown that the nearshore spawning grounds that are popular spawning grounds for Winter Flounder are also vulnerable to water pollution and habitat loss. Tagging studies have shown that Winter Flounder return every year to the same site to reproduce and spawn, meaning that individuals will often revisit to the location where they were hatched, or close by. This implies that there could be populations of Winter Flounder particularly vulnerable to disappearance due to coastal habit loss. If we wipe out a breeding ground then we might cause a particular spawning population to never rebuild.

Certainly there is an unbelievable world under the estuarine waters of Sandy Hook Bay. As warming waters of the bay appeal to more fish, some of those fish will include small fish and young-of-the-year newly spawned juvenile fish. These tiny fish form a massive lower tier of bay's food web during the summer months to feed larger species of fish, such as Striped Bass, Bluefish, Summer Flounder, and Weakfish. These small fish buzz with life and excitement, especially as they try to evade larger fish. No doubt, summer is a busy time for all the fish in Sandy Hook Bay.

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