Pond Boss Forums INTRO Questions & Observations Interesting Abstracts

Differences in CPUE and size structure of largemouth bass and bluegill using day and

night electrofishing

Ray*, B.A. and Murphy, B.R. Virginia Tech, Blacksburg, VA 24061 baray@vt.edu

Many studies have shown that electrofishing during the night produces higher catch rates and larger individuals

than daytime electrofishing; however, due to safety concerns, sampling during the day is preferred. We

sampled two reservoirs in central Virginia to quantify differences in catch-per-unit-effort (CPUE) and mean size

of largemouth bass and bluegill before and after sunset. Each reservoir was sampled bimonthly from April to

October at eight sites. We found no significant differences in largemouth bass CPUE between day and night

electrofishing. The mean length of largemouth bass did not differ among sampling times, however the variance

did decrease throughout the seasons. Conversely, bluegill CPUE was greater at night than during the day;

larger bluegill were more commonly found during nighttime electrofishing, resulting in an increase in the mean

length and variance compared to day electrofishing. These results are important for biologists designing

sampling programs for reservoir management.





Costs of producing all-female largemouth bass for trophy bass fishing

Heep, Tyler D.* and Phelps, Ronald P. Department of Fisheries and Allied Aquaculture, Auburn University, AL

36849 heeptyl@auburn.edu

Trophy largemouth bass are typically females. In the following study, largemouth bass were produced

intensively, fingerlings trained to a formulated diet and cultured to a range of sizes with the goal of determining

the cost of production of manually selected females. Eleven-month old bass were sorted into five size

categories and sexed. The accuracy of manual selection was determined for each size category. The costs of

production (variable costs only) to obtain fry, fingerlings, and sexable-size fish was determined. An average of

14,769 eggs/kg female was obtained, resulting in 4,905 swimup fry/kg female at a cost of $4.84/1000. Nursery

ponds stocked at 148,515/ha yielded 0.97 g fingerlings with a 95.6% survival, at a cost of $53.53/1000.

Fingerlings were stocked into 3 mm mesh net cages, feed trained for 13 days and held an additional 21 days on

a commercial diet. At harvest fish averaged 3.53 g with a 61.2 % survival costing $253.03/1000. Fingerlings

were stocked into ponds at 20,000 and 40,000/ha and cultured 270 days on a commercial diet. Average

weights and survivals at harvest were 179 g and 159 g and 25.3% and 33.7% for the two respective stocking

densities. It was possible to sex fish with 100% accuracy when they were 20 cm and larger. Thirty five percent

of the total number of bass produced were identifiable females. The cost of production of these females was

$5.26/fish when the value of males and unsexable fish at $6.61/kg was deducted from the total production

costs.



Factors influencing Post-Stocking Survival of Hybrid Striped Bass

Port*, P.R., Lochmann, S.E. and W. J. Neal. University of Arkansas-Pine Bluff pport117@yahoo.com

Survival of hybrid striped bass following stocking into small impoundments can be low and is often attributed to

changes in water chemistry and/or temperature. We examined the effects of hardness, temperature, and

acclimation rate on post-stocking survival of hybrid striped bass under controlled laboratory conditions. In the

first laboratory study, hybrid striped bass (mean TL = 139.2 mm, SE = 0.8) were stocked from high hardness

(365 mg/L CaCO3) water into four experimental conditions: 1) low hardness only, 2) low hardness with 5 C

temperature increase, 3) 5 C temperature increase only, and 4) no change in hardness or temperature. In the

second laboratory study, hybrid striped bass (mean TL = 86.9 mm, SE = 1.4) were stocked from high hardness

(350 mg/L CaCO3) water into three experimental conditions: 1) low hardness with 30 minutes acclimation, 2)

low hardness with 60 minutes acclimation, and 3) no change in hardness and no acclimation. For both

laboratory studies, low hardness water had a mean hardness of 52 mg/L CaCO3 (SE = 2.5 mg/L CaCO3), and

fish were observed for 1 week after stocking. There were no significant differences between any of the

treatments in either study, and mortality was low for all treatments. These results suggest that acclimation,

hardness, and temperature are not the primary factors leading to poor survival of hybrid striped bass. We

suggest additional research on handling stress as the primary factor in hybrid striped bass stocking mortality.





Florida Bass Conservation Center: Science-based Bass Stocking Programs

Stout*, R.B. Florida Fish and Wildlife Conservation Commission (FWC), Webster, FL, Porak, W.F., Florida Fish

and Wildlife Conservation Commission, Eustis, FL wes.porak@MyFWC.com

The Florida Fish and Wildlife Conservation Commission’s Florida Bass Conservation Center and Richloam Fish

Hatchery recently received a $15 million renovation to increase production capabilities. The hatchery’s new

production goals include more than 1.5 million fingerlings (<35-mm TL) and up to one million advanced-sized

(~100-mm TL) largemouth bass. We will follow guidelines of our agency’s new fish genetics policy to insure

genetic conservation of wild populations. This will include protecting the genetic integrity of Florida bass

Micropterus salmoides floridanus by genetically testing brood fish, and avoiding translocations of genes from

bass populations in one Genetic Management Unit (GMU) into another as a result of state stocking programs.

Cultured fish will be screened for listed pathogens (e.g., LMBV) prior to their release. Pellet-reared bass will be

fed live fish (e.g. mosquitofish Gambusia affinis) before being stocked, which should enhance their ability to

capture live prey and increase their survival in the wild. Current research efforts are focused on creating genetic

markers using microsatelite DNA technology to differentiate hatchery fish from wild bass, and developing an

experimental artificial diet to avoid a liver disease (that has been observed in bass cultured on commercial

high-protein salmonid diets) and still yield acceptable growth rates. Other research plans include developing

and evaluating different post-release strategies, such as stocking hatchery-reared bass into microhabitats and

acclimation of hatchery-reared fish in temporary holding pens. To assess the success of these new stocking

programs, pre- and post-stocking evaluation protocols will be developed and implemented.





Florida’s largemouth bass stocking programs: a historical perspective

Porak*, W.F., Florida Fish and Wildlife Conservation Commission, Eustis, FL Stout, R., Florida Fish & Wildlife

Conservation Commission, Webster, FL Mesing, C., Florida Fish & Wildlife Conservation Commission, Midway, FL

Cailteux, R., Florida Fish & Wildlife Conservation Commission, Quincy, FL wes.porak@MyFWC.com

The Florida Fish and Wildlife Conservation Commission (FWC) has produced and stocked more than 6.5 million

largemouth bass Micropterus salmoides out of the Richloam Fish Hatchery since the 1960s. We will provide a

historical perspective of our agency’s bass stocking programs, which changed over the years from supplemental

stocking to stocking new waters or stocking degraded populations following drought conditions or fish kills. With

the recent renovation of Richloam Fish Hatchery, emphasis has shifted back to supplemental stocking of

advanced-sized (~100-mm TL) bass raised on artificial diets. Our early research on stocking of advanced sizes

of bass indicated that pellet-reared bass had difficulty transitioning from artificial feed to live prey after being

stocked. Several laboratory studies collectively indicated that the feeding behavior and predation success of

naïve pellet fed largemouth bass differed from experienced wild fish, and that learning of naïve bass occurred

following limited exposure to live prey. Also, fish health problems were suspected from vitamin C (ascorbic

acid) deficiencies and indigestible fatty acids in artificial diets; suggesting the need for a more nutritionally

complete and species-specific diet. The time of year that fish were stocked may have also affected the survival

of stocked fish. Lake Talquin stocking efforts were more successful when the reservoir was stocked with livefeed-

reared largemouth bass at a time when age-0 shad were available as prey. Research findings are being

incorporated into hatchery protocol and new stocking programs.



Latitudinal variation of life-history traits in Centrarchidae

Chizinski, C.J., Department of Natural Resources Management Texas Tech University; Pope, K.L., USGSNebraska

Cooperative Fish and Wildlife Research Unit University of Nebraska-Lincoln; Wilde, G.R. Department

of Natural Resources Management Texas Tech University, Lubbock, TX 79409 chris.chizinski@ttu.edu

Few studies have investigated multiple life-history traits across a latitudinal gradient. Data were collected from

the published literature for 47 populations of bluegill (Lepomis macrochirus), 57 populations of largemouth bass

(Micropterus salmoides), 28 populations of black crappie (Pomoxis nigromaculatus), and 46 populations of

white crappie (Pomoxis annularis). Collected data were used to calculate length-at-age 1 (L1), juvenile growth

rate (G), asymptotic length (Linf), growth efficiency (K), and maximum age (Amax), and determine the

presence of latitudinal trends. The strength of the statistical assessments varied among species, though a

consistent pattern was evident. Generally, L1,G, Linf, and K decreased with latitude, whereas Amax increased

with latitude. L1, G, and Linf, increased with lake surface area, whereas K decreased. Latitude was the most

significant variable explaining the suite of life-history traits, and trends with lake surface area and associated

interaction were inconsistent.



Morphological differences between green sunfish from stunted and non-stunted populations

Sanchez, F.C., Chizinski, C.J., Department of Natural Resources Management Texas Tech University, Lubbock,

TX; Pope, K.L., USGS- Nebraska Cooperative Fish and Wildlife Research Unit University of Nebraska, Lincoln,

NE; Strauss, R.E. Dept. Biological Sciences, Texas Tech University, Lubbock, TX 79409 c.sanchez@ttu.edu

Despite the ubiquity of the stunting phenomena in fishes, little research effort has been devoted to

understanding morphometric implications of stunted morphotype expression. Stunted adult green Lepomis

cyanellus (N=117) and non-stunted adult green sunfish (N=131) were collected from two ponds in west Texas.

Fish images were digitized with TPSDig and gender was identified in the laboratory. Sixteen points were used to

identify 28 morphometric measurements on each green sunfish. Discriminant function analysis was used to

determine morphological differences between sexes (male/female) within and among populations (stunted

/non-stunted). The stunted/non-stunted designation explained 83% of variation in the discriminant function,

whereas the male/female designation explained 14% of the variation. Additionally, there appeared to be very

little sexual dimorphism in stunted green sunfish, whereas considerable dimorphism was observed in nonstunted

populations.

Well I read that all the way through, then I read it again. I think I understand about 41.6% of that post. Obviously since the last part was GSF specific my attention was drawn to that section.

This struck me as odd...

Additionally, there appeared to be very little sexual dimorphism in stunted green sunfish, whereas considerable dimorphism was observed in nonstunted populations.

My first thought was, "Oh great DIED and I have sexual dimorphed GSF." I mean it figures since we live in California but dang.

Then I read this: According to Wikipedia: "Sexual dimorphism is the systematic difference in form between individuals of different sex in the same species. Examples include size, color, and the presence or absence of parts of the body used in courtship displays or fights, such as ornamental feathers, horns, antlers or tusks."

So if I understand this correctly, in my pond and DIED's pond it's easy to tell the boy GSF from the girl GSF but in stunted populations it is not?

I find all of this science stuff confusing, that's probably why I'm a bean counter.

Good stuff. I like the all-female LMB analysis the best.

That's a plethora of potent piscatechnical pot pouri, ewest.


Yes; that's part of the 41.6% I understood myself.

ewest --

Many thanks for sharing these abstracts -- some really fascinating material here.

If I may ask (and I'm not trying to have you divulge "trade secrets" here), what is the source of these abstracts? Did they come from the Southeastern Association of Fish & Wildlife Agencies?

I, too, spend a lot of time researching fisheries topics on the Internet -- primarily for articles I am working on (have taken up outdoor writing in my retirement).

But I have yet to find a good single source for the kind of material you so generously shared. I have found two sites to be particularly _difficult_ to navigate:
the U.S. Fish & Wildlife Service's Federal Assistance site (supposedly the ultimate source of all data/reports linked to Dingell-Johnson/Wallop-Breaux funded State fisheries projects since 1952 ... but it sure ain't!), and the "nbii" site of the U.S. Geological Survey. Again, it is supposed to lead to all available fisheries research pubs that the federal government has funded.

Overall, I would have to say that most state fish & game agency sites I have visited also require a lot of digging to find out what (if anything) they spend on fisheries research efforts.

Anyway, my sincere appreciation for sharing these abstracts -- please keep 'em coming! --

Mike Smith
Lexington, VA

No secrete
AFS http://www.fisheries.org/afs/
has lots of info and these are from the Southern Division

Southern Division
of the
American Fisheries Society

http://www.sdafs.org/


http://www.sdafs.org/meetings/meetindx.htm


Abstracts for oral presentations

and posters presented at the

Southern Division of the

American Fisheries Society

Spring 2007 Meeting



http://www.sdafs.org/meetings/2007/sdafs...tracts_2007.pdf


See this also for sources :

From the archives

Links to Identification Sites

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=92461#Post92461

Many thanks, ewest!

I will follow up on those links and bookmark them! -- Mike S.

Are all those links archived, Eric?

No - just the base link to AFS. Go there and check out the various divisions as they all have good info.