Monday, November 14, 2016

Hutchinson River


Look what I saw in the Hutchinson River. Menhaden Swimming and feeding in the Hutchinson River
I have walked the Hutchinson for a few years now.  When I look at maps I see that the river
after leaving Pelham Lake flows into Eastchester Bay.


Today, I followed the flow of the river after it leaves the lake.  I came upon this sight of
"bunker" feeding.  They are filter feeders, which was evident as they swam by with
their mouths open.


What I found to be unique was that they swam in groups.  Larger fish swam above smaller
fish. It looked like a crisscross pattern .



The New Rochelle Water Company dammed the Hutchinson River in 1886 and 1907, to create three reservoirs (No. 1No. 2No. 3) at the northern end of the community. The Westchester County Park Commission purchased the reservoirs and the surrounding water shed property in 1927, for parkland and parkway purposes.[5] A part of the land was used for the Hutchinson River Parkway, which follows the river for most of its distance.

The Atlantic menhaden (Brevoortia Tyrannus) is a North American species of fish in the herring family, Clupeidae.

Atlantic menhaden are found in the North Atlantic coastal and estuarine waters from Nova Scotia south to northern Florida. They are commonly found in all salinities of the Chesapeake Bay and Mid-Atlantic water. They swim in large schools that stratify by size and age along the coast. Younger and smaller fish are found in the Chesapeake Bay and southern coastline while older, larger fish are found along the northern coastline.

Characteristics
Atlantic menhaden are silvery colored fishes characterized by a moderately compressed body and a black spot on their shoulder behind their gill openings. They can reach a size of approximately 15 inches.

BiologyDiet
Atlantic menhaden are filter feeders, meaning that they collect food by filtering water through modifications of the branchial apparatus (gill arches and gill rakers). Atlantic menhaden’s diet depends on the size of their gill rakers, which change as menhaden age. When the rakers are smaller, which generally correspond to when they are under the age of 1, Atlantic menhaden feed primarily on phytoplankton. As they age and their gill rakers grow larger, menhaden shift their diet to primarily consume zooplankton

Lifecycle
Atlantic menhaden can spawn year round in inshore waters off the Atlantic coast, with the highest spawning rates near North Carolina in the late fall. The eggs hatch in the open ocean and the larvae drift to sheltered estuaries via ocean currents. The young spend a year developing in these estuaries before returning to the open ocean. At this early stage, they are commonly known as "peanut bunker". Atlantic menhaden usually do not become sexually mature until the end of their second year, after which they reproduce until death. A young, sexually mature female can produce roughly 38,000 eggs, while a fully mature female can produce upwards of 362,000.

Eggs are buoyant and hatch within 2 to 3 days depending on the temperature. The larvae will spend 1 to 3 months in waters over the continental shelf. The Chesapeake Bay is a popular nursery for juvenile menhaden. Larval fish will enter the Bay in late winter and early summer. The larval fish will move into lower salinity waters in estuarine tributaries while juvenile and immature fish remain in the Bay until the fall. Atlantic menhaden can live up to 10 to 12 years.

Predators
Atlantic menhaden are preyed upon by fish such as striped bass, weakfish and bluefish, and by birds such as ospreys and eagles. Humpback whales off the coast of New Jersey feed on Atlantic menhaden. Other cetaceans, such as fin whales and dolphins also eat menhaden. Dolphins can eat up to 20 pounds of Atlantic menhaden a day.


No comments:

Post a Comment