Fish Biology
Thermal Niche Preference and Mortality of Striped BassStriped bass (Morone saxatilis) by nature is an anadromous species, meaning they spawn in freshwater and spend the majority of their lives in saltwater. When the Santee River in South Carolina was impounded in the 1940’s to create Santee – Cooper Reservoir a landlocked reproducing population of striped bass came into existence. Offspring from these fish have subsequently been produced and stocked throughout U.S. reservoirs to provide additional angler opportunities. Read more about Striped Bass in Toledo Bend and Sam Rayburn... Double-Crested Cormorants in TexasEveryone that has spent anytime around water in South and East Texas has seen a cormorant. Cormorants are fish eaters and therefore are a topic of discussion among fisheries biologists, lake and pond owners, anglers, and fish farmers. Cormorants are found pretty much worldwide where there is ice-free water. There are two species of cormorants found in Texas – double-crested cormorants and neotropic cormorants, with the double-crested being the most common species. These birds are more abundant from November through May when they are over wintering here, however some birds will remain throughout the year. Read more about double-crested cormorants... Channel CatfishIn another lifetime back in my channel catfish farming days, this is the month that my year always got busy before it got really crazy. With a few million pounds of catfish raised and harvested under my belt, this is a subject I feel fairly comfortable with. If you ever had catfish in a Shoney’s restaurant or in the Louisiana State Women’s Prison in Saint Gabriel, Louisiana then you may have sampled some of my fare. Anyway, I’m getting on a tangent, let’s talk about channel catfish in our area and what makes them tick. Movement of Largemouth Bass Following Tournament-ReleaseTournament fishing is popular at Sam Rayburn Reservoir. TPWD’s most recent estimates indicate that 52% of Sam Rayburn anglers participate in at least one bass tournament per year, compared to only 6% of all Texas anglers. We also estimate that there are over several hundred bass tournaments per year at Sam Rayburn, with tournament fishing (including practice fishing) comprising 36% of the total annual fishing effort, and 46% of the bass fishing effort. Therefore, we know that tournament anglers handle a large number of bass every year at Sam Rayburn, and some of these fish may be relocated greater than 20 miles from their original capture point. In addition, because a majority of the larger tournaments conduct weigh-ins at the lower, southeast end of the reservoir, concentration of largemouth bass at weigh-in sites is also likely. These concerns can affect overall angler catch rates, both in a negative (relocation) and positive way (stockpiling following weigh-ins). If stockpiling is severe, fish growth, body condition, and survival may be reduced. Read more about tournament fishing at Sam Rayburn Reservoir... Hydrilla 101, Part 1Hydrilla! You mention this aquatic plant and some reservoir constituents are all smiles (primarily anglers) while others label it the world’s worst aquatic weed (swimmers, water skiers, homeowners, industrial and municipal users, etc.). Both sides of the issue have merit in certain situations. Before we explore both beneficial and detrimental scenarios associated with hydrilla (Part 2 of this topic in a future Lakecaster issue), a little biological/life history information is in order. |
LARGEMOUTH BASS SPAWNING AND FACTORS FOR SUCCESSWell, it’s that time of year when things start to happen. Specifically, to all of us fish heads we associate spring with spawning and wonder what this year will eventually bring three to five years from now from the result of all those largemouth bass being born. We all reap today what we have sown yesterday, so it goes with fish as well. Read more aboutbass and spawning... Crappie Don’t Make for Good Fisheries BiologyTPWD just finished trap netting for crappie at Sam Rayburn to try and find some measure of crappie abundance for the lake (I emphasize the word try here). Before I go any further I’ll explain what a trap net is and why they are usually a poor sampling tool for crappie, even though they are our current weapon of choice. A trap net consists of four 2.5’ diameter hoops that are connected to two 3’x 6’ frames with a 60’ leader. TPWD has used trap nets for years to gauge crappie populations throughout the state. The things we are looking for when we deploy these nets are how many crappie we catch in each of these nets per night and the size structure of the fish and how this compares to previous years. TPWD protocol dictates we are to set these trap nets perpendicular off the bank. Now I know what you crappie fishermen are sitting there thinking, that crappie are further from the bank than that 60’ leader and we probably won’t catch very many fish, and you are correct. Recently, TPWD allowed its district biologists to determine whether or not trap nets are used as an index tool for crappie populations at lakes they are responsible for. This was done because the catch rates from most trap nets are so low that it is impossible to come to any conclusion as to what it means. A good trap net haul in most lakes around here will be at best 10 fish with most hauls ranging from no fish to about 5 fish. What does 5 fish caught in a trap tell you about a population of fish on a 5,000 or 25,000 or a 100,000 acre lake? Not much. My boss the district biologist realizes this and we have opted out of using trap net data to make any determination about the crappie populations for the lakes we manage. Bass Regulations 101Often, especially when I am out doing creel surveys, I come across fishermen that want to know why TPWD has a certain bass regulation in place versus some other regulation. Depending on what the fishermen’s motivation is, more often than not the appropriate regulation they feel is needed is the one that will likely impose the least restriction over them compared to other fishermen with different fishing motivations (i.e. harvest, release, tournament, non-tournament, etc.). The goal of any fishery regulation is to ensure long term sustainable quality use of a natural resource. Texas has three general types of bass regulations – minimum length limits, slot length limits, and catch and release only.
Read more about bass regulation 101... Warming Water Temperatures Trigger Sport Fish SpawnAlthough air and water temperatures are still relatively cool, longer days and increasing air temperatures are slowly warming area lakes. Increasing lake temperatures begin to stimulate natural spawning instincts of many area sport fish. In preparation for the upcoming spawning season, most sport fish undergo increasing levels of activity. When one mentions increased fish activity, anglers are never very far behind. Those that pay attention to spawning requirements of targeted species can better their springtime fishing success. Black Bass 101Depending on whom you are talking to, the “black bass” name might mean a couple of different things. Most often, I find that when anglers refer to black bass, they are specifically referring to largemouth bass. However, from a biology perspective, the phrase “black bass” is actually a group that includes seven closely related species classified by the scientific genus Micropterus. In other words, although a largemouth bass is a black bass, so are spotted bass, smallmouth bass, and four other similar species. |