Forums - View Single Post - The Large breeders
View Single Post
Old 08-31-2006, 12:38 AM
Striperjim's Avatar
Striperjim Striperjim is offline
Registered User
Join Date: Mar 2004
Location: Planet Earth
Posts: 4,316
Default The large breeders

Article in entirety. (certificate error)Link

The South Carolina Striped Bass:

A Unique Story

The striped bass, sometimes known as the "Rock", "Rockfish" or "Striper" has a long and interesting history in South Carolina. It is the "state game fish" and the "state fish." The scientific name of the striped bass is Morone saxatilis and it is typically catalogued as an anadromous fish. Anadromous means that it spends the greater part of its life in the ocean and travels to freshwater streams to spawn. Over the past century, fish biologists have reported that striped bass populations have steadily declined. This decline is primarily due to pollution, siltation, construction of power dams and overfishing. Striped Bass are found along the Atlantic Coast from the St. Lawrence River in Quebec and ends in the St. John’s River in Florida. North of Cape Hatteras, the Striped Bass is an anadromous fish. It is one of the most popular saltwater sport fish along the eastern seaboard.
In the spring, the Striped Bass enters freshwater, traveling up rivers to spawn. When spawned, fertilized eggs must have a volume and flow of water that insures at least 48 hours flotation. If they sink, the eggs die. Once hatched the fry begin their journey down river and enter saltwater as fingerlings, juvenile fish. In South Carolina, the striped bass tend to spend the greater part of its life in freshwater streams. Once it was believed that the Santee-Cooper population of Striped Bass had become landlocked because of the construction of two dams that impounded Lake Moultrie and Lake Marion. More recently, fish biologists have come to believe that the Striped Bass in South Carolina were "functionally" landlocked or "riverene" long before the dams were built. This means that they have become residents of the river naturally. This is supported by the current research. Therefore, the Santee-Cooper Striped Bass population is entirely a freshwater population (Campbell, Striped White & Hybrid Bass in South Carolina).
Striped Bass have a tendency to travel in small schools during the first two years of life. They have enormous appetites and feed on shad, menhaden, herring and minnows. Spawning grounds for Striped Bass are typically in streams and rivers with moderate to fast current flowing over a rock or sand bottom. In South Carolina, the spawning period ranges from April 1 to May 15. During this time, the males typically migrate to the spawning grounds first and wait until the larger females arrive. Spawning is governed by water temperature and it starts when the water is around 58-60 degrees F. Spawning of Striped Bass involves several small males surrounding one large female as she lays her eggs freely into the running water. No spawning "bed" or "nest" is created by Striped Bass. The males jockey for position creating much splashing which is known as a "rock fights." The males brush against the female to stimulate spawning. After the eggs are laid, milt from the males then fertilizes the eggs. Studies have shown that greater than 80 percent of the eggs are usually fertilized. The eggs at the time of fertilization are very small and nonadhesive and settle to the bottom. After a short time, the eggs swell to about four times the original size and possess a tiny oil globule. This change makes the egg approximately the same density of the surrounding water. The eggs become somewhat buoyant and are easily carried by the water currents. The hatching time varies from 65 hours at 60 degrees F to 36 hours at 70 degrees F. According to Bulak (1988), if a striped bass spawned at 70 degrees F in a low rainfall year, approximately 36 miles of flowing water is necessary for the eggs to hatch. But if a striper spawned at the same temperature during a high rainfall period, about 72 miles of flowing water from the spawning area is required. A flow velocity in the river of approximately one-foot per second is required to keep the eggs afloat. If the egg sinks to the bottom, its chances of hatching are reduced because the sediments reduce oxygen exchange between the egg and the surrounding water. The flow rates of the water are basically controlled by the upstream flows from dams. Egg mortality is high, especially in water temperatures above 70 F, but many eggs are laid to increase survival. Less than one percent of the eggs will survive the fist two months.
Bulak (1988), stated that "In most years, the prime spawning grounds are in the upper Congaree, between the city of Columbia and the Eastman Kodak plant. But in years of low water, such as 1985 and 1986, striped bass do not migrate as far upstream to spawn. This points out once again, the impact river flow can have on spawning migration (p. 44)."
Depending in the size of the female, one female can lay from 14,000 (3 pounder)-3,000,000 eggs (10 pounder). A thirty-pound female is capable of producing as many as five million eggs. In a fast moving current, the eggs hatch out at a considerable distance downstream from the spawning place. At the time of hatching, the tiny transparent fish, less than ΒΌ inch long emerges with a heavy yolk sac attached. It derives nourishment from this sac. The fry at this stage is at the mercy of the water currents. Within four to five days, the yolk sac is absorbed and the fry begins to swim and feed on small crustaceans (Scruggs, 1954).
Male Striped Bass usually reach sexual maturity at two years. They are generally less than 12 inches long. About 25% of the females reach maturity at four years of age when they are about 17 inches in length. Nearly all of the females are mature at five years of age when they reach a weight of six pounds or a length of twenty-three inches. Age studies have shown that the Striped Bass grow slowly during the first two years. The rate of growth of females is faster then that of the male. The average length of a striper is 20-36 inches, while the average weight is 3-10 pounds. Striped Bass attain a maximum weight of 60 pounds in freshwater and 125 pounds in saltwater, but fish over 55 pounds are rare (Bayless, 1982).
In South Carolina, the majority of the spawning occurs in the Wateree and Congaree Rivers, which are tributary streams of Santee-Cooper. Results of a 1983 study indicated that the Congaree River is a major spawning area while additional studies in 1987, now show that the majority of striped bass egg production comes from the Wateree River. In 1973, the SC Wildlife and Marine Resources Department, now known as the SC Department of Natural Resources, reported that there are five main rivers which support populations of Striped Bass: the Cooper, Santee, Congaree, Wateree, and Saluda above Lake Murray. Excellent reservoir fisheries exist in Lakes Marion, Moultrie, Murray and Wateree. Smaller populations are found in Lakes Hartwell, Thurmond, Secession and Greenwood. Biologist believe that a slow moving current in a short stretch of river or a faster current in a longer river may provide the necessary time for eggs to develop and hatch. They believe that of all the state’s rivers, which empty into reservoirs, only the Congaree and Wateree provide the correct ratio of length and flow necessary for reproduction. It should be noted that most striper populations in reservoirs are maintained solely by stocking. This stocking benefits other game fish such as largemouth bass and crappie. The striper seeks out fish such as gizzard shad for its main food supply, thus eliminating fish that would compete with wanted game fish (Davis, 1973).
In the early 1960’s, SCDNR fishery biologists provided the key to propagating Striped Bass artificially by experimenting with various hormones to speed up spawning. The pioneering efforts by Dr. Robert E. Stevens put Striped Bass hatcheries on a reliable production basis. This technique plus the documentation that Striped Bass in the Santee-Cooper River system was "landlocked", opened a new era of Striped Bass culturing and fishing. It enabled the expansion of Striped Bass into land-locked reservoirs (Bayless, 1982). These techniques have allowed the stocking of Striped Bass in many reservoirs in the United States. Since the1970’s, many anglers throughout the United States now enjoy Striped Bass fishing. Freshwater striped bass fisheries are now in almost every state because of what was discovered in the Santee-Cooper System (Bulak, 1988). In More information about striper production at state hatcheries may be found in the Hatchery Section of this guide.
In recent years, the low rate of hatching survival of striper eggs in Santee-Cooper, indicate that something is affecting the ability of stripers to successfully reproduce and maintain their populations. In hopes of speeding up the recovery of Santee-Cooper striped bass populations, the daily creel limits in 1989 were reduced from 10 stripers to five in lakes Marion and Moultrie and the rivers nearby. Therefore, the law prohibits keeping more than five striped bass or any striped bass less than 18 inches long in the following waters: Lake Marion, Lake Moultrie, Diversion Canal, Rediversion canal, Tailrace Canal, Santee River, Congaree River, Wateree River, Lower Saluda River, Broad River northward to the lock and dam of the Columbia Canal, Cooper River (no length limit) and Wando (no length limit) (South Carolina Wildlife Roundtable, M-A, 1990). In 1993, it was discovered that heavy fishing was creating the reduction of striper populations in the Santee-Cooper lakes. The striped bass are caught so fast and in such large numbers that few of the fish live long enough to reproduce. DNR studies have shown that 80% of the Lake Marion and Moultrie female stripers are caught before they reach spawning size. This reduction of egg-laying females and other factors has caused the drastic decline in the striper population in the two reservoirs (Bulak, Wethey, and White III, 1995). It was stated by DNR fisheries biologists that we have now have to stock more than two million hatchery-reared fish into the lakes each year to meet the demands of fishermen. This may suggest that the 18 inch minimum size limit needs to be changed, or lower the daily creel limit to ease the fishing pressure (South Carolina Wildlife Roundtable, M-J, 1993).
Miller White, District Fisheries Biologist for DNR, is now tagging striped bass in the Santee-Cooper lakes to get a better understanding of the factors influencing striper populations. He feels that the tagging study can produce valuable information about striper management. Fishermen are asked to report the tagged stripers they catch. For this study. DNR will even pay $20 for each tag reported (South Carolina Wildlife Roundtable, J-A, 1997).
The answer to the Striped Bass problem is still being worked on by DNR fisheries biologists. Hopefully, a solution is in sight. In reference to striped bass, the current DNR Rules & Regulations 1998-99 state for striped bass the creel limit is 10 fish per day, except five fish per day and a 21-inch minimum size limit in ten specified areas of the state (page 8).
Reply With Quote