Beware ! Great Lakes Aquatic Fish Invasions.
MONDAY AUGUST 16TH 2010
As these “invasive fish species” are eminent to arrive in the Great lakes, as a painful reminder that oil is not the only one of man’s activities that threatens to DECIMATE ENTIRE ECOSYSTEMS. We need to set priorities in the search for solutions for Great Lake Aquatic Invasions ! One of the most significant “threats” to biodiversity in the Great Lakes – St. Lawrence region is the introduction into an ecosystem of species that are non-indigenous. Already, new species have invaded the Great Lakes, and others are on their way.
The Great Lakes are the largest freshwater seas in the world with 80,500 sq. miles of surface area. An index for fish biology has been body condition , and Lake Trout have been a key species for indicating ecosystem health of the Great Lakes.
Hamilton Harbour’s fish at risk to “aquatic fish invasions” are: (1) At Bay-front Park the fish habitat is integrated into the shoreline; 65 underwater structures were installed to create an artificial reef; and, it has increased native fish species density. (2) At Cootes Paradise, it is a natural spawning area for native Pike. (3) Grindstone Creek Estuary has 200 spawning Pike which is a dramatic improvement from 19 Pike previously recorded. (5) La Salle Park has 125 fish habitat structures. (6) the Northeastern Shoreline has a fish diversity from 6 – 18 species in 78 fish habitat modules. Other areas in Hamilton Harbour include: Indian Point, Willow’s Point, Carrolls Point, and Hamilton Harbour to the east as fish areas. Fish species include:
- Small Mouth Bass, Large Mouth Bass, Silver Bass, Walleye, Crappie, Pumpkin-seed, Northern Pike, Chinook Salmon, Lake Trout, Catfish, Smelt, Alewife, Gizzard Shap, Rainbow Trout, Brown Trout, White Sucker, Emeral Shiner, Spottail Shiner, Brown Bullhead, Rock Bass, Blue Gill and Yellow Perch.
“Fish Fears have excellerated as a 2,005 study pointed to the Snake-head fish coming to Canada as “high.” including the southern Great Lakes area. The reason Snakehead Fish came to the U.S. is two-fold: (1) the aquarium trade, and (2) transport as fish food to live fish markets. They are a popular food due to their excellent taste and can be found in Vietnamese pot dishes, or, pickled, smoked and dried. The Origin of Snake-heads (Channidae) a freshwater fish native to Asia, from Pakistan to China, to Thailand, to Cambodia and Borrena; besides Russia, Korea and Africa. Now they are in the U.S. and on their way to Canada.
Will the Northern Snake-head Fish Decimate
Great Lake Fish Ecosystems ? The 2,005 study says, “only the Northern Snake-head can survive in Canadian waters.” These fish reach maturity at 2 to 3 years old. EACH spawning female can release 15,000 eggs at once. Furthermore, they can mate as often as five times a year. Therefore, mathematically, in two years time, a single female can release 150,000 EGGS. And, as they can “walk” on land, they lay their eggs in a nest they build in vegetation in shallow water.
SNAKEHEADS HAVE NO NATURAL ENEMIES ! They grow fast after hatching and feed on plankton, aquatic insects and mollusks. As Adults: they are attracted to light and may come out of their cover to feed on prey. They eat anything that moves: fish, frogs, snakes, and even birds and rodents. They ambush their food and swallow them whole, or, cut their prey in half with their sharp teeth. They are large, up to 1 meter in length, with big mouth , large tongue, sharp teeth and huge eye.
MAJOR PROBLEM – SNAKEHEADS EAT GAMEFISH ! THEY OVERCROWD A BODY OF WATER (i.e,, Hamilton Harbour) AND HARM NATIVE SPECIES. Without any predators, they can adapt to any water with little oxygen. They have a physiological need to breathe atmospheric air, with a suprabranchial organ: a primitive form of labyrinth organ that lies under their long dorsal fin. They breathe air unlike other fish – by using this primitive lung above the gills. The adults force the young to breath by pushing them to the surface. They travel short distances on land, rhythmically moving their fins and muscular bodies = “walking”. They will not attack people but may injure anyone stepping on them.
Carp have been an issue in Hamilton Harbour. But, the key piece of the 1993 Project Paradise was the installation of the FISHWAY. This is a carp barrier and two way fishway structure designed to keep non-native carp out of Cootes Paradise Marsh, while still maintaining a two-way flow of native fish.
“Voracious Eaters” are two kinds of ASIAN CARP “a dangerous invasion species” that can grow and weigh 100 lbs. are: Bighead Carp and Silver Carp. They prefer Rivers, but, if they reach the Lakes and breed, they could “decimate plankton ” which is the basis of the food chain for native fish.
Asian Carp were brought to the U.S. in the 1970s to clean algae from catfish farms. They escaped captivity and have spread through the Mississippi River and tributaries. In May 2,010 little Calumet River tried “poisoning.” as a control method. But, of the 100,000 lb. fish being killed, NO ASIAN CARP WERE FOUND. Then on June 23, 2,010 in Lake Calumet, only six miles from Lake Michigan a 3 foot long Asian Carp was found “a dangerous invasive species of fish: ! Fishermen, water skiers, swimmers beware – when startled by boat motors, Asian Carp “jump.”
As conservationists reporting any citing of “invasive fish species” is paramount to prevention of them decimating our Great Lakes Entire Ecosystem.
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