INTRODUCTION

American shad Alosa sapidissima and hickory shad Alosa mediocris have been protected in Maryland since 1980 and 1981, respectively, by a moratorium (Markham et al. 1994).    American shad had supported both a commercial and a sport fishery in Chesapeake Bay and some of the larger tributaries such as the Susquehanna River. The hickory shad was never a targeted commercial species, although it was marketed when landed. It was sought mostly while on spawning migrations by recreational anglers in smaller streams such as Deer and Octoraro Creeks, both tributaries of the Susquehanna River.
Most information on the life history of the hickory shad deals with spawning movements and little is known of the adults after they leave the spawning grounds. Coastal migration patterns may be similar to that of the American shad  (ASMFC 1988). Most of their adult life is spent in marine waters, but they return to freshwater streams in the spring to spawn. Spawning populations are river-specific (ASMFC 1988).
Hickory shad are predators in the ocean, their diet consisting of small fish, crustaceans and fish eggs (Breder 1948). They exhibit aggressive behavior in freshwater, making them available to recreational anglers. Opinions are mixed whether this striking is a feeding behavior or non-feeding aggression (Dale Weinrich, Maryland Department of Natural Resources, personal communication). Anglers use a variety of lures to take hickory shad. Shad darts, small spoons and soft bodied “twister tails” are used with spinning tackle and variable patterns are fished with fly tackle. Live bait is not used to take hickory shad.
Anecdotal information from biologists and anglers indicates that over the last several years there has been an increase in the observed number of hickory shad returning to Deer and Octoraro Creeks and to other rivers (Dale Weinrich, Maryland Department of Natural Resources, personal communication). There has been an increase in catch and release hickory shad fishing by both fly and spin fishers in Deer and Octoraro Creeks and in the mainstream Susquehanna River. Maryland law does not prohibit fishing for hickory shad, even though there is a ban on their possession.
In Maryland, anglers target American shad mostly in the mainstream Susquehanna River, although hickory shad are also taken there. We have observed most of the fly and spin fishing for hickory shad in the smaller tributaries, particularly Deer Creek. Spin fishing is favored at the mouth, as deeper and faster water make wading difficult and stream bank vegetation inhibits fly fishing. Most fly anglers fish the area above Stafford Bridge on Deer Creek, but spin fishers also angle here.
In Deer Creek, fishing for hickory shad begins during either the last week of March or the first week of April when water temperatures reach 46 to 50 F (Dale Weinrich, Maryland Department of Natural Resources, personal communication). Angler pressure varies with time of day and day of the week. Weekend evenings have the greatest number of anglers present.
Location and light levels influence angler success. Certain spots or structures in streams are holding areas for hickories. Striking activity is most intense around first light and again at fading daylight. Mildly discolored, or turbid water from runoff reduces light penetration and can improve angler success during mid-day, but extreme high flows and turbidity reduces angler success. Experienced anglers believe that several runs or surges of fish occur during the spawning season.
Muoneke and Childress (1994) defined immediate hooking mortality as the proportion of fish that are landed and exhibit no opercular movement. It included fish so severely injured from hooking they were judged incapable of recovering. Delayed mortality in some species, such as largemouth bass Micropterus salmoides, occurred up to 19 days following release (Schramm et al. 1987). Most catch and release mortalities of salmonids, rainbow trout Oncorhynchus mykiss, (Mason and Hunt 1967), and brown trout Salmo trutta, (Hulbert and Engstrom-Heg 1980), occurred within 24 hours. Studies by Warner and Johnson (1978) found that all mortality of Atlantic salmon Salmo salar caught in streams occurred within 24 hours.
The Maryland Department of Natural Resources recognizes the value of catch and release fishing as non-consumptive recreation. However, catch and release fishing may cause an unacceptable level of mortality in some situations. Muoneke and Childress (1994) found hooking mortality increased with temperature.
Hickory shad were scarce in Chesapeake Bay spawning tributaries until two years ago. To preserve this apparent recovery, the impact of catch and release fishing activity needs to be measured and, if necessary, addressed. This study was to determine the short-term mortality rate among hickory shad on their spawning run caused by catch and release fly fishing.

METHODS

Our study was conducted on Deer Creek in Harford county. Of the two possible study streams, Octoraro and Deer Creeks, Deer Creek has a more intense fishery. Our study site was chosen because of the availability of electrical power and proximity to a good fishing location.
We defined short term mortality as fish dying within 48 hours. We conferred with other biologists that have worked with shad who felt that a 48 hour period was sufficient for detecting catch and release mortality  (S. Ault, Radiation Management Corporation,  personal communication). Hickory shad were on their spawning migration and were very active. Holding times in excess of 48 hours could have induced “confinement mortality” and fungal infection was also a concern.
We did not use control fish, we assumed that confinement mortality would be low. Control fish would have been hickory shad not subjected to stress of capture but only stressed by confinement. However, any method of obtaining wild hickory shad would have imparted stress. Murphy et al. (1995) found overall end mortality of caught and released spotted seatrout Cynoscion nebulosus was very low (4.6%) and the researchers concluded that confinement did not cause significant mortality.
Volunteer fishermen captured experimental fish with 4 to 7 weight fly rods and a single hooked artificial lure, sometimes tandemly rigged. Barbed and barbless hooks were used. Once hooked, the fish was played normally and landed by hand or into a net. Time required to land the fish was recorded for some individuals. Anatomical location of the hook wound was noted. The hook was removed, the fish was transported in a wet cotton sling to shore and released into an observation tank. If the fish was foul hooked, we marked it by punching a hole in the membranous portion of the upper lobe of the caudal fin. A maximum number of 25 were used in any test.
Two 340 gal circular fiberglass tanks, 5.0 ft in diameter and 30 in deep, were used to hold fish for observation following capture and release. A centrally located standpipe drained each tank. Water was supplied to the tanks by means of a 1.0 horsepower Hayward electrical pump (115 volts, 10.0 amps). Electrical power was provided through the cooperation of Baltimore City’s Deer Creek Water Pumping Station. Pump capacity resulted in approximately ten exchanges of water in each tank per day. Water was introduced to the tanks above the surface to maximize aeration and at an angle to create a current into which the fish would orient. Water was drawn from Elbow Branch, a tributary of Deer Creek, approximately 100 ft from the confluence with Deer Creek. We recorded water temperature (F), dissolved oxygen (mg/L), pH and conductivity (µmhos/cm) daily from both creeks to document differences. Tanks were covered with blue polypropylene tarps to prevent the fish from jumping out or being frightened by onlookers.
Fish were observed daily for mortalities.  Following 48 hours of observation, we marked the fish with a hole punch in the membranous portion of the upper lobe of the caudal fin and released them into Deer Creek.
We made counts of dead fish in Deer Creek each Monday during the study. The portion of the creek from Stafford Bridge to the confluence of Elbow Branch, a distance of approximately one half mile, was surveyed by foot and dead fish were counted and retrieved, if possible. The fish which could be retrieved were examined for wounds and marks indicating that they had been study fish.

RESULTS

We conducted ten trials of 5 to 30 fish per trial from April 12 to May 3, 1996. The number of fish per trial varied due to angler success. No short-term mortality of hickory shad occurred due to angling (N= 150). At release, all fish were vigorous and swam off under their own power. No fungus was seen. One hundred and forty fish (93.3%) were caught in the maxillary or the mandible. Ten fish (6.7%) of the 150 total were foul hooked. All foul hooked fish survived the 48 hour observation period.
Fight times for 32 fish varied from 30 seconds to 2 minutes 20 seconds. Most anglers landed fish in under one minute.  Three extreme playing times were recorded (greater than 2 minutes) and all three were foul hooked fish.
Stream counts of dead fish were made on April 15, 22 and 29. High, discolored water prevented a count on the final day of the study. Thirteen dead fish were recorded. Nine fish were recovered and seven had physical injuries consistent with having been hooked. Five fish had oral damage and two were foul hooked, both in the back. Two additional fish were recovered and examined; one was severely damaged, possibly by an osprey and the other was unmarked.
Thunderstorms and heavy rainfall resulted in water levels in both Deer Creek and Elbow Branch rising during the night of April 15-16 (Trial III). Flood waters carried away some of the pumping system and possible damage was sustained by the pump as evidenced by repeated loss of prime during the rest of the study. Trial VII was terminated at the end of 24 hours. The pump failed and 22 of 25 fish died because of low dissolved oxygen.
Water temperature, pH, dissolved oxygen, and conductivity were monitored each day in both tanks, Elbow Branch and Deer Creek. Water temperatures did not differ greatly between the tanks and Deer Creek except during Trial III when tank temperatures were 5F less. All other trials differed by 3F or less. Conductivity and pH were consistent between the tanks and the creek. Conductivity never differed by more than 0.015 µmhos/cm and pH differed by less than 0.6. Oxygen levels were generally within 1.0 mg/L, except for Trial III when the flood damage shut down the pump.

DISCUSSION

We did not observe short-term mortality of hickory shad from catch and release fly fishing in our experiments. Absence of mortality among the test fish should be tempered by the presence of a few dead fish in the stream. It is not possible to determine if their death was the result of angler involvement, but hook injury was documented on most (77.7%) of the fish examined. We polled fisheries management agencies from Maine to North Carolina on hickory shad hook and release mortality and found no other studies had been conducted on angler induced mortality of hickory shad.
Artificial lures were used to capture hickory shad and none of the fish observed during this study were deeply hooked. Our observations of spin fishermen on Deer Creek indicated that most of these fish were also not deeply hooked. Fly fishing was selected because fly fishermen volunteered to participate.
This study focused on the issue of short term survival of hickory shad caught and released. It did not address the possibility of longer term effects such as interruption of the spawning migration or spawning success. Reingold (1975) reported that migrating adult steelhead trout Salmo gairdneri caught and played to exhaustion, and then transported downstream returned to their target stream as well as fish just transported and released. Pettit (1977) reported that there was not a statistically significant difference in the percentage of eyed eggs produced by caught and released steelhead trout compared to control fish.
Hickory shad used in this study were not given extraordinary care. They were played in a normal manner with sporting tackle, landed, and handled to place them in our experimental tanks (which represented an additional stress not associated with catch and release fishing). This study suggests that a hickory shad hooked, played, and landed by a conscientious angler will not experience an unacceptable level of angler induced mortality.

Literature Cited

ASMFC (Atlantic States Marine Fisheries Commission). 1988. Supplement to the Fish      Management Plan for the Anadromous Alosid Stocks of the Eastern United States:     American Shad, Hickory Shad, Alewife, and Blueback Herring. Washington D.C.
Breder, C . M. 1948. Marine Fishes of the Atlantic Coast, G. P. Putnum and Sons, New York.
Hulbert, P. J. and R. Engstrom-Heg. 1980. Hooking mortality of worm caught hatchery brown    trout.     New York Fish and Game Journal 27:1-10.
Markham, C. A., J. P. Mower. A. A. Jarzynski, R. A. Sadzinski, and D. R. Weinrich. 1994.        Investigation of anadromous alosids in Chesapeake Bay. Federal Aid Project F-37-R.
Markham, C. A., P. G. Piavis, E. J.Webb, B. H. Pyle, J. P. Mower, A. A. Jarzynski, R. A. Sadzinski, and D. R. Weinrich. 1996. Stock assessment of selected adult resident and     migratory recreational finfish in Maryland’s Chesapeake Bay. Federal Aid Project
F-54-R.
Mason, J. W. and R. L. Hunt. 1967. Mortality rates of deeply hooked rainbow trout.         Progressive Fish-Culturist 29:87-91.
Muoneke, M. I. and W. M. Childress. 1994. Hooking mortality: a review for recreational     fisheries. Reviews in Fisheries Science 2(2): 123-156.
Murphy, M. D., R. F. Heagy, V. H. Neugebauer, M. D. Gordon, and J. L. Hintz. 1995.     Mortality of spotted seatrout from gill-net or hook-and-line gear in Florida. North     American Journal of Fisheries Management 15:748-753.
Pettit, S. W. 1977. Comparative reproductive success of caught-and-released and unplayed     hatchery female steelhead trout (Salmo gairdneri) from the Clearwater river, Idaho.     Transactions of the American Fisheries Society 106:431-435.
Reingold, M. 1975. Effects of displacing, hooking, and releasing on migrating adult steelhead     trout. Transactions of the American Fisheries Society 104:458-460.
Schramm, H. L.,Jr., P. J. Haydt, and K. M. Portier. 1987. Evaluation of prerelease,         postrelease, and total mortality of largemouth bass caught during tournaments in two     Florida lakes. North American Journal of Fisheries Management 7:394-402.
Warner, K. and P. R. Johnson. 1978. Mortality of landlocked Atlantic salmon (Salmo salar)     hooked on flies and worms in a river nursery area. Transactions of the American     Fisheries Society 107:772-775.

Note:  The following article was condensed for Careful Catch readers in April 2011 by Maryland DNR Fisheries Biologist Rudy Lukacovic.  The regulations cited were those in effect during the time of the original publication and are not current.  For current fishing regulations visit the Maryland DNR fishing regulations website.

Mortality Rate of Striped Bass
Caught and Released with Artificial Lures
During Spring on the Susquehanna Flats.

Prepared by
Rudy Lukacovic
and
Ben Florence

Introduction
A catch-and-release fishery has developed for striped bass Morone saxatilis in the upper Chesapeake Bay during the spawning season. Most fishing in this area is concentrated on the Susquehanna Flats, an area above a line from Turkey Point on Elk Neck to Sandy Point on Spesutie Island at Aberdeen Proving Grounds. The Susquehanna Flats are currently included as part of the upper bay striped bass spawning area. Regulations are in effect that prohibit catching, harassing, pursuing, hunting, shooting, wounding or attempting to catch striped bass or striped bass hybrids in this area and other spawning rivers. These restrictions are in effect from March 1 to May 31.
The Susquehanna Flats is an area of low to no salinity, particularly in spring. Release mortality for striped bass in warm water (>25C; 77F) is higher in freshwater (RMC 1990). At temperatures of 16-23.5 C (61-74F) Nelson (1998) showed the mean adjusted mortality for striped bass 293-610 mm (11.5-24 in) was 6.4%. Data concerning the mortality rate of striped bass greater than 610 mm (24 in) caught and released in a low salinity, low temperature environment does not exist.
Controversy has resulted because participants in the fishery believe a legal catch-and-release fishery can exist without adversely impacting striped bass populations or spawning.  Additionally, the prohibition of targeting striped bass is difficult to enforce because it is hard to prove in a court of law that an angler actually intended to catch a striped bass.
A workgroup composed of various stakeholders was formed by Maryland’s Fisheries  Service to meet and discuss the issues regarding this situation. Stakeholders were comprised of recreational and commercial fishermen, Maryland Charter Boat Association representatives, Cecil County Chamber of Commerce members, Maryland Sport Fish Advisory Commission members and Fisheries Service scientists. After two meetings, it was the consensus of this workgroup that the Fisheries Service design and conduct a study to determine the mortality of striped bass associated with catch-and-release fishing under these environmental conditions.

Methods
Charter boats captains, professional guides and experienced local fishermen were hired, or volunteered, to catch striped bass for this study. Two charter boats and two to four smaller vessels were designated to fish for two consecutive days each week of the study. Workgroup members, stakeholders and Department  of Natural Resources personnel caught fish on board the designated vessels. A cross section of fishing experience was represented. Department of Natural Resources-Fisheries Service boats accompanied the fishing boats to transport striped bass to holding pens.
Fishing was restricted to the Susquehanna Flats. Three trials were conducted over a five week period to evaluate the influence of seasonality. The Flats were fished on April 20-21 (Trial I), May 4-5 (Trial II), and May 18-19 (Trial III), 1998. Each trial consisted of two consecutive, single day replicates. Fish from day 1 were held separate from day 2 fish.
Terminal tackle was limited to single hooked artificial lures. Participating anglers used medium action spinning and casting rods equipped with 10-15 pound test line.
If a fish was shallow hooked (defined as hooked in the lip or mouth) it was marked with a    hole punched through the lower lobe of the caudal fin. If a fish was deep hooked (hooked in the gullet or stomach) a hole was punched in the dorsal lobe of the caudal fin. A fish hooked in the gills was marked with two holes in the lower lobe, and a foul hooked fish (defined as hooked externally anywhere posterior to the eyes) had one hole punched in each lobe of the caudal fin. Each fish was placed in a tank on board a transport vessel.
Fish were divided into two groups: greater than or less than 610 mm. Twenty fish of each size group were targeted for each replicate. Any fish in excess of twenty from each size group were measured, sexed, hook location recorded and released. An additional 20 fish from a pound net were to be added to the pen.
On April 20-21 one Fisheries Service vessel was used to transport fish caught by all fishing boats.  Three Fisheries Service transport boats, each assigned to accompany a specific charter boat or group of smaller fishing boats, were used on May 4-5 and May 18-19.
Each transport vessel was equipped with a circular fiberglass tank and oxygen. Upper bay water was pumped into the tanks and was kept oxygenated to ambient levels. Once 10 to 15 fish were captured, they were taken to holding pens. Water in the tank was exchanged between each trip.
Fish were placed in floating net-pens. Net pens were 4.6 m (15 ft) square by 3.7 m (12 ft) deep and were suspended by a floating wood and styrofoam frame. They were anchored in 3.0 m (10 ft) of water. Pens were checked every day for three days.
Each net was emptied after three days of observation. Survivors were released after being measured, sexed and hook location (hole punch position) recorded. Mortalities were discarded after being measured, sexed, if possible and hook location recorded.
Surface and bottom temperature (C), salinity (ppt), dissolved oxygen (mg/l) and pH were recorded at the fishing sites and in the transport tanks several times each day of fishing. These parameters were also recorded at the pens each day of the study.
Results

During Trial I (April 20-21), a total of 653 fish were caught by all boats participating in the study. Forty nine small fish and 12 large fish were placed in the net-pens (26 on day 1 and 35 on day 2). One female (875 mm), gravid when caught, was among the 61 fish used in the mortality segment. This fish released her eggs while in the net-pen. All others used as part of the mortality segment of Trial I were males. Three fish that were deeply hooked and two that were foul hooked survived. One large shallow hooked male died (8.3% of the large fish; 1.6% of the total). Nine pound net fish were also placed in the nets, 6 on day 1 and 3 on day two. Four pound net fish died (44.4%) during the 72 hour observation periods. Five hundred ninety two fish that were caught and not used in the mortality segment were released.  Total length, sex and hook location were recorded for some individuals.
Water temperatures during Trial I ranged from 13.3-15.8C (57-59F). Dissolved oxygen ranged from 7.85-11.0 mg/L and pH varied from 7.12-7.88. Salinity was constant at 0.0 ppt.
Trial II (May 4-5) caught 912 striped bass. One hundred and nine were used for the mortality portion of the study. Seventeen large fish, including three unspawned females (792-900 mm) were put in the net-pens for this trial. After 72 hours, four mortalities were documented among 92 small fish (4.3% of the small fish; 3.7% of the total). One death occurred among 5 deep hooked fish. The other 3 mortalities were shallow hooked fish. All three females survived and still retained their eggs at release. Two of the three large females had been tagged the previous year by DNR. No fish from pound nets were used in this trial.
Water temperatures in this trial ranged from 15.9-16.6C (61-62F). Dissolved oxygen levels were between 9.58-10.45 mg/L, and pH varied from 7.48-8.27. Salinity was again constant at 0.0 ppt.
One hundred and seven striped bass, out of 344 caught, were put in the net-pens for Trial III (May 18-19). Twenty three of these fish were greater than 610 mm and three mortalities were documented in this size group (13.0%). Fourteen mortalities (16.7%) were counted among the 84 fish less than 610 mm. The mortality combining both groups was 15.9%.  All mortalities were males with the possible exception of one large, 761 mm (30.0″) fish, which was too decomposed to determine sex. Two females were identified by dissection among the small fish. Five females were recorded in the group of larger fish and all still retained their eggs at release. One of seven deep hooked fish died.
Water temperature increased from 17.6C (64F) to 21.9C (71F) during this trial. Dissolved oxygen levels varied from 8.73 to 10.25 mg/L and pH ranged from 7.32 to 8.37. Salinity was constant at 0.0 ppt.
The mortality rate combining all fish for all trials was 7.9%. The mortality rate for the small fish (n=225) was 8.0% and 7.7% for the large fish (n=52).

Discussion

Stress and physical injury are the two major factors that influence survival of fish that are caught and released. Temperature, fish size and salinity are the most influential stress-related factors that affect the survival rate of striped bass that are caught and released (RMC 1990). The physical damage associated with hook injury has been documented as the single most important factor in hooking mortality (Muonke and Childress 1994).
In the study design, fish size, water temperature and hook location were considered variables influencing catch and release mortality. Salinity was constant at 0.0 ppt throughout all three trials and was not considered a variable. Upper bay salinity is usually very low, if present at all, especially during the spring.
Striped bass were grouped as “large” or “small” fish in this study. This designation was based on the lack of hooking mortality data for striped bass greater than 610 mm caught in fresh water (0.0 ppt salinity) at low temperatures (<70F).
In this study eighteen mortalities (8.0%) were documented among fish less than 610 mm (N=225).  There was no significant difference in their mortality rate compared to 52 fish greater than 610 mm. Four mortalities (7.7%) were recorded among the large size group.
Temperature was the only factor affecting fish survival in this study. Nelson (1995) reported an adjusted mortality over five trials of 7.3% for striped bass caught on artificial lures at salinities of 0.0 ppt and temperatures between 16.0-23.5C (60.8-74.0F). Mortality at 16.0C (60.8 F) was 0.0% but rose to 17.6% at 22.0C (71.6F). At a middle temperature of 19.0C (66.2F) mortality was 6.7%.
The total mortality in Trial I of this study was 1.6% at temperatures of 13.8-15.0C (57-59F). During the second trial it increased to 3.7% at 16.2-16.6C (61-62F). Striped bass died at a rate of 15.9% during Trial III with temperatures ranging from 17.6C (63.6F) to a high of 21.9C (71.3F).
Higher temperatures and the rate of temperature change may have worked in combination to exacerbate mortality in Trial III. During Trials I and II, temperatures were low and did not increase appreciably or rapidly during the 72 hour holding period.  The temperature during Trial I (F=1.6%) increased 0.9C (1.5F). Trial II (F=3.7%) increased 0.3C (0.5F). As expected, the temperature during Trial III (F=15.9%) was higher than the other two trials. Trial III also experienced the greatest and most rapid increase in temperature. At the start of fishing on May 18, temperature was 17.6C (63.6F). Temperature increased to a high of 21.9C (71.3F) on May 21, a change of 4.3C (7.7F). It decreased to 20.2C (69.3F) at release on the last day.
The release of water from Conowingo Dam on the Susquehanna River, 4 miles above its mouth, affects the area of the flats where the net-pens were anchored. Pulses of water for power generation from Conowingo pool are drawn from deeper and cooler levels. This appeared to occasionally affect temperatures at the pens.
Hook location did not play a significant role in mortality in this study. Single hooked artificial lures were used to eliminate terminal tackle as a variable. Some participating anglers did use treble hooks, but changed lures when asked.
Fifteen fish (5.4%) were deep hooked among 277 striped bass used in the caging experiment. Two mortalities (13.3%) were documented among deep hooked fish less than 610 mm. Two fish larger than 610 mm were deep hooked and both survived.
Natural baits such as blood worms and cut fish are used in the upper bay to catch white perch Morone americana and channel catfish Ictalurus punctatus and these baits also take striped bass. Increased mortality rates from higher deep hooking frequencies using natural baits have been documented for smallmouth bass Micropterus dolomieu (Clapp and Clark 1989), brook trout Salvelinus fontinalis, brown trout Salmo trutta  and rainbow trout Oncorhynchus mykiss (Shetter and Allison 1955; Stringer 1967), and bluegill sunfish Lepomis macrochirus (Siewert and Cave 1990). However, mortality was not considered significantly different for largemouth bass Micropterus salmoides (Rutledge and Pritchard 1977).
Two field studies which evaluated hook location, fish size and season reported the mortality of deep hooked striped bass caught on bait to be 41% in the fall and 56% in the spring (Lukacovic and Uphoff 1997). During 1995 striped bass were hooked in specified deep or shallow anatomical locations and held under controlled conditions for 60 days at the Cooperative Oxford Laboratory (K. Lockwood, Maryland Fisheries Service, personal communication). Deeply hooked striped bass died about 57% of the time in this experiment. The low deep hooking rate was anticipated because artificial lures were used exclusively to capture fish for this study.
The lower rate of mortality among the deep hooked fish caught with single hooked artificial lures verses those caught with single baited hooks can, in many cases, be attributed to hook orientation. It was not possible to determine hook orientation in every deep hooked fish because of the distance between boats. When such an examination was made the hook was consistently pointed dorsally. The hook was removed from all fish except one that was hooked in the roof of the mouth. This fish, a 620 mm male, with the bucktail still in-situ survived the 72 hour holding period and was vigorous when released.
Necropsies are routinely performed on all dead, deep hooked fish. In the study, which used natural bait on single hooks, the hook was oriented downward in 31 of 40 deep hooked fish. Damage to the heart and/or liver is the most common result and hemorrhage is usually profuse. This damage was easily seen as most fish died within 6 hours and post-mortem change was not severe. In this study with artificial lures, only two deep hooked fish died and no organ damage or sign of hemorrhage was seen in either the abdominal or peritoneal cavities. Mortalities did not float and were not documented until the nets were pursed at the end of 72 hours. Post-mortem changes obscured any subtle focal damage that may have resulted from a single point of penetration.
No “floaters” were seen in the net-pens during any of the trials. Low temperatures may have retarded decomposition and associated gas production. Dead fish were only documented when the nets were pursed at the end of each trial replicate. The current, which was almost constant, billowed the net and may have held some fish down below the surface.  When the mortalities were discarded, all sunk, except some of the fish from Trial III which appeared neutrally buoyant. Post-mortem change was variable among the mortalities in Trial III suggesting that deaths occurred over time. Mortalities that were documented in the spring study, which used baited hooks, all floated. This information is not available for the fall segment.
Pound net fish were used in Trial I. The commercial pound net from which they were taken was 7 miles from the net-pens.  Wind conditions on one of two days that pound net fish were used was severe (20-25 mph). Transportation of pound net fish was so different from hook and line caught fish that no comparison of survival is possible. Their use was discontinued for Trials II and III.
A total of 1909 striped bass were caught during all 3 trials. One hundred and thirteen fish (5.9%) were greater than 610 mm. Two hundred and seventy seven striped bass, 225 small fish, 52 large fish were put in the net-pens. Nine of 52 large fish (17.3%) used in the mortality study were females. Two females (0.9%) were documented among 225 small fish. Expansion of these percentages to all fish caught suggests that 20 of 113 large fish and 16 of 1796 small fish were females.

References

Diodoti, P.J., and R. A. Richards. 1996. Mortality of striped bass hooked and released in salt water. Transactions of the American Fisheries Society 125:300-307.
Harrel, R. M. 1988. Catch-and-release mortality of striped bass caught with artificial lures and bait. Proceedings of the Annual Conference Southeastern Association of Fish and     Wildlife Agencies 41:70-75.
Hollis, E. H. 1967. An investigation of striped bass in Maryland. Maryland Department of Natural Resources, Federal Aid in Fish Restoration, Project F-3-R, Annapolis.
Hysmith, B. T. 1992. Hooking mortality of striped bass in Lake Texoma, Texas-Oklahoma. Proceedings Annual
Conference Southeast Association Fish and Wildlife Agencies     46:313-420.
King, H. 1994. Policy for catch-and-release fishing. Memorandum: Maryland Department of Natural Resources, Tidewater Administration, Annapolis, Maryland.
Lukacovic, R. and J. H. Uphoff. 1997. Hook location, fish size and seasonality as factors     influencing catch-and-release mortality of striped bass caught with bait in Chesapeake Bay.
Muoneke, M. I. and M. W. Childress. 1994 Hooking mortality: a review for recreational fisheries. Reviews in Fisheries Science. 2:123-156.
Nelson, K. 1998. Hooking mortality of striped bass in Roanoke River, North Carolina. North American Journal of Fisheries Management. 18:25-30.
Pankhurst, N. W. And D. F. Sharples. 1992. Effects of capture and confinement on plasma cortisol concentrations in the snapper (Pargrus auratus). Australian Journal of Marine     and Freshwater Research 43:345-356.
Pettit, S. W. 1997. Comparative reproductive success of caught-and-released and unplayed female steelhead trout (Salmo gairdneri) from the Clearwater river, Idaho. Transactions of the American Fisheries Society 106:431-435.
Reingold, M. 1975. Effets of displacing, hooking and releasing on migrating adult steelhead trout. Transactions of the American Fisheries Society 104:458-460.

Note:  The following article was written in 1998 by Maryland DNR Fisheries Biologist Rudy Lukacovic.  He condensed the paper in March 2011 for Careful Catch readers.  The regulations cited were those in effect during the time of the original publication and are not current.  For current fishing regulations visit the Maryland DNR fishing regulations website.

.

Recreational Catch-and-Release Mortality of White Perch
Prepared by Rudolph Lukacovic
(1998)

INTRODUCTION

Management of recreationally important fish involves the use of tools such as minimum size restrictions, creel limits and/or closed seasons. Currently white perch Morone americana  caught by recreational fishermen in Maryland are not protected or regulated by any of these management options.
White perch was the primary species targeted by recreational anglers in spring in the Choptank and Chester Rivers in 1996 and 1997 (Sadzinski and Webb 1998). White perch accounted for 85% of the four most commonly caught and released species (white perch, yellow perch Perca flavescens, channel catfish Ictalurus punctatus and white catfish Ictalurus catus). The general fishing experience for white perch on the Choptank was ranked the highest by anglers among the four targeted species, however 57% of those anglers interviewed ranked the fishing as only fair or poor. Twenty five percent of the white perch caught from the Choptank River in 1996 were harvested and represented 91% of the overall harvested catch. Anglers that targeted white perch in 1996 ranked the fishing as poor (30%), fair (27%), good (37%) or excellent (6%).
In the future it is possible that a minimum size restriction or creel limit for recreational fishing might be considered as a means of manipulating the size structure of the population. White perch less than 8 in were harvested at rates well below their proportion in the population because anglers generally prefer fish over 8 inches.
Minimum size limits are used to protect and enhance fish populations by allowing fish to live long enough for them to spawn one or more times. It is also an effective way to provide quality fishing by preventing the harvest of smaller individuals and allowing a greater number fish to survive to a more desirable size. Creel limits reduce fishing mortality if they are less than typical angler catch. Minimum size limits and creel limits will work if survival rate of the released fish is high.
White perch are among the three most sought-after recreational species in Maryland’s Chesapeake Bay and its tributaries (Sadzinski and Webb 1998) and are often caught using bait. Muoneke and Childress (1994) reported that natural baits were often swallowed more deeply by fish than artificial lures and resulted in higher mortality. Siewert and Cave (1990) reported that worm-baited hooks were ingested deeper by bluegill Lepomis macrochirus, resulting in significantly higher mortality (88%) than when the same species was caught with artificial lures (28%).
Fisheries Management Plan stock assessment committees recommend that programs monitor and quantify discard levels. Currently anglers are discarding 75% of the white perch they catch and most are less than 6.5 in. The mortality rate of white perch that are caught and released is not known. If the mortality rate is high for released fish, a minimum size may not be an appropriate management tool.

METHODS

The mortality study was conducted on Unicorn Branch, a tributary to the Chester River. This site, located at a Maryland Department of Natural Resources-Fisheries Service field office, was selected because of its proximity to electrical power and access to a large number of anglers who provided fish as test specimens. White perch stage a spring spawning migration in this stream and concentrate in the spill-way below the dam at the state-owned Unicorn pond.
Recreational anglers were asked to donate white perch they would normally have released. Fish were taken from anglers that used spin fishing gear with shad darts baited with live grass shrimp. All hooks were barbed. This was the most common angling technique used at this site for white perch. Fish were hooked and played normally and if not desired by the angler were placed in a water filled 5.0 gal bucket. Hook location was indicated by hole-punching the caudal fin. Shallow hooked fish, defined as hooked in the lips, mouth or gills, were unmarked. Deep hooked fish, defined as hooked in the gullet or stomach, were marked in the upper lobe of the caudal fin. Foul hooked fish were defined as being hooked in the external surface anywhere posterior to the eyes and were marked in the lower lobe of the caudal fin.  Fish were transported to holding tanks in the buckets.
Two 340 gal circular fiberglass tanks, 5.0 ft wide and 30 in deep were used to hold fish. A central stand pipe drained each tank. Water was supplied to the tanks by means of a 1.0 horsepower electrical pump (115 volts, 10.0 amps). Pump capacity resulted in approximately twelve exchanges of water in each tank each day. Water drawn from Unicorn Branch, was piped under the service road through a culvert and introduced to the tanks above the surface to maximize aeration and at an angle to cause a current into which fish would orient. Water temperature (C) was recorded in both tanks and Unicorn Branch each day. Tanks were covered with locking wooden lids.
White perch were observed daily for mortality. After 48 hours they were measured, sexed, hook location (hole punch position) recorded and then released.

RESULTS

Five hundred and twenty four white perch were used in six trials conducted between March 28 and April 4, 1998. One white perch (0.2%), a 7.6 in female, was lip hooked and died during the first 24 hours after capture during Trial III. All released fish appeared vigorous when released and swam off under their own power. None of the wounds on the foul hooked fish appeared to be infected.
The number of fish in each trial varied due to the number of anglers present at the site and their success. Approximately 56% (292) fish were males. They ranged in total length from 5.3- 9.0 in and averaged 7.2 in. About 44% (232) were females. Female white perch ranged in total length from 6.3-9.6 in and averaged 7.5 in. Most white perch (95.4%) were shallow hooked, 4.4% were foul hooked and 1 fish (0.2%) was deep hooked.
Water temperature increased at a relatively constant rate during the first four trials,  declined slightly during Trial V and leveled off during the last trial. Pump capacity produced approximately 12 exchanges of water each day in each tank. As a result stream and tank temperatures remained the same throughout the entire study. Water temperature was 60F on the first day of the experiment and 67F on the last day. The greatest change occurred during Trial II when the temperature increased from 62-65F. All other trials had a change in temperature of 2F) or less.

DISCUSSION

The mortality among released white perch under the conditions of this study (low water temperatures, no salinity) was very low (0.2%). Only a single fish was deeply hooked and deep hooking is usually a significant contributor to release mortality (Muoneke and Childress 1994). Anglers used grass shrimp (Palaemonetes) on a shad dart. Natural baits alone are more often swallowed deeply and their use can result in higher mortality. The combination of a natural bait on an artificial lure produced a very low rate of deep hooking in this study.
Twenty three fish (4.4%) were foul hooked and all survived. Foul hooking was defined in this study as a hook wound in the outside body anywhere posterior to the eyes. Foul hooked white perch were generally wounded in the back or shoulder area, away from any vital organs.
The white perch spawning migration is initiated by rising water temperatures. The study began when the white perch arrived at the spillway below Unicorn Pond to spawn. Temperature and salinity have been shown to influence the survival of striped bass Morone saxatilis that are caught and released (RMC 1990; Lukacovic and Uphoff 1997). High temperatures and low salinities can increase mortality associated with stress. In this study temperatures remained low and did not appear to exacerbate mortality from stress. Salinity was non-existent at this site.
Average size and size range of fish used in this study were not representative of all fish in the stream because anglers tended to keep larger fish. White perch donated to this study would have been released either because of undesirable size or because anglers were catch-and-release fishing. The criteria that individual anglers used to judge whether a fish was desirable was not consistent. Eighty four percent of the fish used in this study were less than 8 inches. If minimum size regulations or creel limits were to be considered in the future, survival of released fish in the spring spawning run fishery is high enough for these measures to be successful.

LITERATURE CITED

Lukacovic, R. and J. Uphoff. 1997. Hook Location, fish size and seasonality as factors     influencing mortality of striped bass caught with bait in Chesapeake Bay. Maryland     Department of Natural Resources, Fisheries Service, Annapolis, Maryland.

Mouneke, M.I. and M.W. Childress. 1994. Hooking mortality: a review for recreational     fisheries. Reviews in Fisheries Science 2: 123-156.

RMC, Inc. 1990. An evaluation of angler induced mortality of striped bass in Maryland.     Completion Report (P.L. 89-304, AFC-18-1) to National Marine Fisheries Service,     Gloucester, Massachusetts.

Sadzinski, R.A. and E.J. Webb. 1998. Assessment of the 1997 recreational finfish harvests in     the Choptank and Chester rivers and summer head boat surveys. In Piavis, P.G., B.H.     Pyle, A.A. Jarzynski, R.A. Sadzinski, E.J. Webb, C. Markham, J.P. Mower, R.     Lukacovic and D.R. Weinrich. Stock assessment of selected resident and migratory     recreational finfish species within Maryland’s Chesapeake Bay. Federal Aid Project F-    54-R. Annual Report, Department of the Interior, Fish and Wildlife Service.

Siewert, H.F. and J.B. Cave. 1990. Survival of released bluegill Lepomis macrochirus caught     on artificial flies, worms, and spinner lures. Journal of Freshwater Ecology 5:407-411.


Recreational Catch-and-Release Mortality of Yellow Perch During Their Spring
Spawning Migration.
(2002)
Prepared by: Rudy Lukacovic

Introduction

Management of recreationally important fish generally involves the use of such tools as minimum size restrictions, creel limits and/or closed seasons or areas. Currently yellow perch Perca flavescens caught by recreational fishermen in Maryland’s tidal waters are regulated by all of these management options.
Yellow perch caught by recreational anglers in Maryland’s tidal rivers are protected by a size limit and a creel limit. A (9 in) minimum size limit is required for yellow perch caught from the tidal waters of Maryland’s Chesapeake Bay, except those closed to harvest. Harvest is prohibited in the Magothy, Nanticoke, Patapsco, Severn, South and West rivers. A five fish per day creel limit is in effect for all open tidal waters.
Recreational anglers fishing the spawning tributaries in spring have increasingly focused on yellow perch. In 1998, 9.7% of interviewed anglers fishing the Choptank and Chester rivers targeted yellow perch (Webb and Zlokovitz 1999). In 1999, 37% were targeting yellow perch (Zlokovitz and Webb 2000).
Yellow perch comprised 29% of the total of all species caught (harvested and released combined) by anglers fishing the Choptank and Chester rivers in 1999 (Zlokovitz and Webb 2000). White perch Morone americana represented another 67%. However, harvested catch consisted of 80% white perch and only 17% yellow perch. In both systems 88% of the yellow perch caught by recreational anglers were released. This difference in percent harvested is reflective of there being no size limit for white perch and a relatively high one for yellow perch.
Fisheries management plan stock assessment committees recommend that programs monitor and quantify discard levels. Yellow perch are a highly sought-after recreational species in Maryland’s Chesapeake Bay tributaries during their spring spawning migrations. Currently anglers are discarding 88% of the yellow perch they catch while the mortality rate of sub-legal (< 9 in) yellow perch that are caught and released is not known. A study was undertaken during spring 2002 to quantify losses and identify factors contributing to these losses. This data would provide management with information regarding the effectiveness of size and creel limits for this fishery.

Methods

A tank system to hold caught-and-released yellow perch was set up on Wye Stream, a tributary to the Wye River East. This site, located at the Maryland Department of Natural Resources, Wildlife Management Wye Mills field office, was selected because of its access to a large number of anglers who would provide fish as test specimens. Yellow perch stage a spring spawning migration in this stream and concentrate in the spill-way below the dam at the state-owned Wye Pond.
Two 340 gal circular fiberglass tanks were used to hold fish. Water was supplied to each tank by means of separate siphons pulling water from the pond. Flow to each tank was approximately 7 gal per minute. A central stand pipe drained each tank. Water temperature was recorded in both tanks and Wye Stream each day. Tanks were covered with locking wooden lids.
Recreational fishermen, representing a variety of angling experience, were asked to donate yellow perch they would normally have released. Fish were taken from anglers that used spin-fishing gear with shad darts baited with live grass shrimp (Palaemonetes spp.) or minnows (Fundulus spp.). All hooks were barbed. This was the most common angling technique used at this site for yellow perch. Fish were hooked and played normally and if not desired by the angler were placed in a water filled 5.0 gal bucket. Hook location was indicated by hole-punching the caudal fin. Shallow hooked fish, defined as hooked in the lips, mouth or gills, were unmarked. Deep hooked fish, defined as hooked in the gullet or stomach, were marked in the upper lobe of the caudal fin. Fish were transported to holding tanks in the buckets.
Yellow perch were observed daily for mortality. After 48 hours, the surviving fish were measured, sexed, hook location was recorded and released. Temperature was recorded each day in the tanks and in the stream below the test site.

Results

Cooperating anglers provided 241 yellow perch for the study. These fish were used in nine 48-hour trials that began on March 2 and continued through March 18, 2002. Number of fish used in each trial was dependent on number of anglers and their success. Yellow perch used per trial varied from five to 53. Yellow perch averaged 9.1 in total length and ranged in size from 6.6 – 11.9 in. Male yellow perch were predominant in the catch, representing 87.6% of the fish used in this study. Female yellow perch represented 11.2% of the test fish and 88.9% of those females had already spawned at the time of capture. Sex could not be determined for three yellow perch (1.2%). More than half of the test fish (56.8%) were greater than the minimum legal size 9 in.
Among the sub-legal fish (n= 104), males were the predominant sex, representing 91.3% of that group. Females accounted for 6.7% of the sub-legals and the remainder (1.9%) were unknown.  All sub-legal females were spent.
Anglers also caught pumpkinseed sunfish Lepomis gibbosus, black crappie Pomoxis nigromaculatus, brown bullhead Amerius nebulosus, largemouth bass Micropterus salmoides, and golden shiner Notemigonus crysoleucas. Most of these fish were of undesirable size and were released. Largemouth bass were closed to harvest.
The deep-hooking rate for all yellow perch was 5.8%. Deep-hooking rates ranged between trials from 0.0% to 60.0%. Deep hooking occurred less than 12.5% of the time during all trials except one trial with a small sample size (Trial 5). Among sub-legal yellow perch deep-hooking occurred 8.7% of the time.
Deep-hooking mortality was 35.7% for all yellow perch. Sub-legal yellow perch that were deeply hooked died 33.3% of the time. Shallow-hooking mortality was 0.9% for all yellow perch. No shallow-hooked sub-legal yellow perch died in any trial. Overall mortality in this study, and mortality of sub-legal yellow perch was the same (2.9%).
Water temperatures in Wye Stream ranged from a low of 42.1°F in Trial 2 to 57.6°F in Trial 9. Water temperatures in the tanks differed slightly from stream water temperatures during some trials. The maximum difference in temperature between the stream and the tank was 1.8°F and there was no difference in the temperatures in three trials. The greatest change in tank water temperature during any one 48-hour trial occurred during Trial 9 (+5.4°F).

Discussion

Minimum size limits are used to protect and enhance fish populations by allowing fish to live long enough for them to spawn one or more times. Length limits may also provide quality fishing by preventing the harvest of smaller individuals and allowing a greater number of fish to survive to a more desirable size. Creel limits reduce fishing mortality if they are less than the typical angler catch. Minimum size limits and creel limits assume a high rate of survival among released fish.
Mortality among released yellow perch under the conditions of this study (low water temperatures, no salinity) was low (2.9%). Anglers used grass shrimp or minnows on a shad dart. The combination of a natural bait on an artificial lure produced a fairly low rate of deep hooking among all yellow perch in this study (5.8%) as well as among the sub-legal fish (8.7%).  A study evaluating catch-and-release mortality for white perch on their spawning migration in Unicorn Branch, a tributary of the Chester River, showed anglers using similar terminal tackle shallow hooked their fish 95.4% of the time (Lukacovic 1999). Muoneke and Childress (1994) report that natural baits are often swallowed more deeply by fish than artificial lures and their use results in higher mortalities. Siewert and Cave (1990) reported that worm-baited hooks were ingested deeper by bluegill, resulting in significantly higher mortality (88%) than when the same species was caught with artificial lures (28%).
Shallow hooking mortality was extremely low in this study. Sub-legal yellow perch that were shallow-hooked experienced no mortality and only two of 227 yellow perch (0.9%) greater than the minimum size of 229 mm died. Size-related mortality among shallow-hooked striped bass caught in warm water has been documented in several catch-and-release studies (RMC 1990, Lukacovic and Uphoff 1997).  Larger fish fight longer and are more difficult to handle than smaller fish. Differences in the ratio of gill surface area to body volume increase as fish get larger. Therefore larger fish have a more difficult time eliminating carbon dioxide from their bloodstream and re-oxygenating their tissues after extreme physical exertion. However, for striped bass caught at low water temperatures fish size was not a factor. (Lukacovic and Florence 1999).
Deep-hooking mortality, as expected, was markedly higher, 35.7%. The physical injury associated with swallowed hooks caused profuse bleeding that was clearly visible in most cases. Mortality was extremely rapid as most deaths among deep-hooked fish were documented with minutes. Significant differences in mortality between deep and shallow hooked fish have been consistently documented in catch-and-release mortality studies (Siewart and Cave 1990, Bugley and Shepard 1991,  May 1973, Lukacovic and Uphoff 1997, Lukacovic 2000).
The yellow perch spawning migration is initiated by rising water temperatures. Fish migrate from estuarine areas of tidal tributaries such as Wye River into upper freshwater reaches.  Spawning generally begins when water temperatures reach 44°F; Piavis 1991). Temperatures during Trial 1 were 43.5 – 47.5F, then decreased during Trial 2. This experimental site may have been subject to more rapid changes in water temperature than some other spawning streams. Water is supplied to Wye Stream from the surface of Wye Pond, a 48 acre state-owned lake. Diurnal heating and cooling of the surface water of the lake resulted in more rapid changes in water temperature in the spillway than in other streams that are not affected by a large shallow body of water immediately upstream. The study began when the yellow perch arrived at the spillway below Wye Pond to spawn. Temperature and salinity have been shown to influence the survival of striped bass that are caught and released (RMC 1990; Lukacovic and Uphoff 1997). High temperatures and low salinities can increase mortality associated with stress. In this study temperatures remained low and did not appear to exacerbate mortality from stress. Salinity was non-existent at this site.
Average size and size range of fish used in this study were not representative of all fish in the stream because anglers tended to keep larger fish. Yellow perch donated to this study would have been released either because of sub-legal or undesirable size, or because anglers were catch-and-release fishing. The criteria that individual anglers used to judge whether a fish was desirable was not consistent.
Man-made impediments to migration in some spawning streams, such as the dam at Wye Pond or beaver dams will cause fish to concentrate below these structures. This site at Wye Mills was selected because of high angler participation in this fishery and high rates of angler success. Also access to Wye Pond provided sufficient height difference in water levels to produce enough head pressure needed to run the siphon system.
A similar experimental design has been used successfully in previous catch-and-release studies conducted by Maryland’s Fisheries Service. These studies have evaluated recreational release mortality using artificial lures (sometimes with natural bait added) under similar environmental conditions (low water and air temperatures and freshwater, i.e. no salinity). American shad Alosa sappidissima caught by recreational anglers using unbaited shad darts below Conowingo Dam on the Susquehanna River in 1997 experienced a 48 hr mortality of less than 1% (Lukacovic 1998). Hickory shad Alosa mediocris caught and released by fly fishers in Deer Creek suffered no mortality after 48 hrs (Lukacovic and Pieper 1996). White perch caught on baited shad darts experienced release mortality <1% (Lukacovic 1999). Low mortality was anticipated for yellow perch in this experiment.
Maryland regulations require barbless hooks to be used when targeting yellow perch in tidal waters. An informal query of fishers at Wye Stream indicated only one of approximately 30 anglers asked were aware of this regulation. Barbless hooks can reduce handling time when removing the hook from fish. There is no evidence to suggest that they reduce deep hooking. Under the environmental conditions recorded in this experiment, shallow-hooking mortality was low; less than 1% for all fish, and 0% for sub-legal fish. Therefore, no substantial increase in survivorship would be gained by reducing handling time.
Even though sub-legal fish represented less than half of the fish used in this study (43.2%) they represented almost two thirds of the deep hooked fish (64.3%). Smaller fish may be more competitive and exhibit  more aggressive feeding behavior.
The majority of the yellow perch sport-fishery occurs during spring with cool air and water temperatures. Survival rates of both legal and sub-legal sized yellow perch are high enough under these circumstances, that size and creel limits appear to be effective management practices for this species.

References
Bugley, K. and G. Shepard. 1991. Effect of catch-and-release angling on the survival of black sea bass. North American Journal of Fisheries Management. 11:468-471.

Lukacovic, R. and L. Pieper. 1996. Short-term mortality of hickory shad, Alosa mediocris, caught and released by fishermen in Deer Creek, Maryland. Maryland DNR. Fisheries Service Technical Report Number 19. Annapolis,  Maryland.

Lukacovic, R. 1998. Mortality of American shad Alosa sapidissima caught and released by anglers below Conowingo Dam. Maryland Department of Natural Resources, Fisheries Technical Report Series, Number 21, Annapolis, Maryland.

Lukacovic, R. 1999. Catch and Release Mortality of White Perch. In Piavis, P.G., B.H.  Pyle, A.A. Jarzynski, J.C. Walstrum, R.A. Sadzinski, E.J. Webb, H.W. Rickabaugh Jr., E. Zlokovitz, J.P. Mower, R. Lukacovic , K Whiteford and D.R. Weinrich. Stock assessment of selected resident and migratory recreational finfish species within Maryland’s Chesapeake Bay. Federal Aid Project F-54-R. Annual Report, Department of the Interior, Fish and Wildlife Service.

Lukacovic, R. 2000. Hooking mortality of deep and shallow hooked striped bass under different environmental conditions in Chesapeake Bay. In: Weinrich, D.R., P.G. Piavis, B.H. Pyle, A.A. Jarzynski, J.C. Walstrum, R.A. Sadzinski, E.J. Webb, H.W. Rickabaugh, E. Zlokovitz, J.P. Mower, R. Lukacovic, K.A. Whiteford. Stock assessment of selected resident and migratory recreational finfish species within Maryland’s Chesapeake Bay. Federal Aid Project F-54-R. Annual Report, Department of the Interior, Fish and Wildlife Service.

Lukacovic, R. and J. Uphoff. 1997. Hook location, fish size and seasonality as     factors influencing mortality of striped bass caught with bait in Chesapeake     Bay. Maryland Department of Natural Resources Technical Memo No. 16,     Annapolis, Maryland.

Lukacovic, R. and B. Florence. 1999. Mortality rate of striped bass caught and released with artificial lures during spring on the Susquehanna Flats. Maryland Department of Natural Resources, Annapolis, Maryland.

May, B. E. 1973. Evaluation of large scale release programs with special reference to bass fishing tournaments. Proceeding of the 26th Annual Conference of Southeastern Association of Game and Fish Commissions, 26:325-329.

Mouneke, M.I. and M.W. Childress. 1994. Hooking mortality: a review for recreational     fisheries. Reviews in Fisheries Science 2: 123-156.

Piavis P.G.. 1991. Yellow Perch. Pp14.-14.15. In Funderburk, S.L., J.A. Mihursky, S.J. Jordan, and D. Riley (Eds.). Habitat requirements for Chesapeake Bay living resources, 2nd Edition. Living Resources Subcommittee, Chesapeake Bay Program. Annapolis, MD.

RMC, Inc. 1990. An evaluation of angler induced mortality of striped bass in Maryland. Completion Report (P.L. 89-304, AFC-18-1) to National Marine Fisheries Service, Gloucester, Massachusetts.

Siewert, H.F. and J.B. Cave. 1990. Survival of released bluegill Lepomis     macrochirus     caught on artificial flies, worms, and spinner lures.     Journal of Freshwater     Ecology 5:407-411.

Webb and Zlokovitz. 1999. Assessment of the 1998 recreational finfish harvests in the Choptank and Chester rivers and summer head boat surveys. In Piavis, P.G., B.H. Pyle, A.A. Jarzynski, J.C. Walstrum, R.A. Sadzinski, E.J. Webb, H.W. Rickabaugh Jr., E. Zlokovitz, J.P. Mower, R. Lukacovic , K Whiteford and D.R. Weinrich. Stock assessment of selected resident and migratory recreational finfish species within Maryland’s Chesapeake Bay. Federal Aid Project F-54-R. Annual Report, Department of the Interior, Fish and Wildlife Service.

Zlokovitz and E.J. Webb. 2000. Assessment of the 1999 recreational finfish harvests in the Choptank and Chester rivers and summer head boat surveys. In Piavis, P.G., B.H. Pyle, A.A. Jarzynski, J.C. Walstrum, R.A. Sadzinski, E.J. Webb, H.W. Rickabaugh Jr., E. Zlokovitz, J.P. Mower, R. Lukacovic , K Whiteford and D.R. Weinrich. Stock assessment of selected resident and migratory recreational finfish species within Maryland’s Chesapeake Bay. Federal Aid Project F-54-R. Annual Report, Department of the Interior, Fish and Wildlife Service.

Reprinted with permission from Chesapeakelighttackle.com

To fizz or not to fizz, that is the question a lot of yellow perch fishermen have been asking lately. As you can see by this sonar shot, yellow perch can hold in a wide range of depths this time of year in the Chesapeake Bay. At issue is that a few of the fish we catch from the deepest water come up with distended swim bladders. Since we inevitably land a few that are under the legal size limit, they have to be released.  Because of all the air in their bodies, they can’t always swim back down.  This leaves them floating on top of the water where they are vulnerable to birds and other predators. The practice of puncturing a fishes swim bladder with a hypodermic needle or other sharp object to relieve pressure is called fizzing.  It works for some species, but for others it isn’t such a good idea.  What about yellow perch? This week, I put the question to the experts. I spoke with several fisheries biologists I know, including some at the Maryland Department of Natural Resources.  Here’s what I learned.

The swim bladder in freshwater fish like yellow perch allows them to control their buoyancy by regulating the amount of gas in their bodies.  Some fish have ducts in their air bladder that allow them to change depths quickly, but yellow perch do not.  When they change depths the air has to be expelled through tiny capillaries. That’s a very slow process. When fish are holding in deep water they have to use a lot more pressure to stay down.  When they’re brought up quickly by a net or hook and line, they don’t have time to blow off the pressure, so the swim bladder becomes over-inflated. This can result in bulging eyes, protrusion of internal organs  such as their stomachs though the mouth, damage to internal organs, hemorrhaging, and other problems.

When I heard that, my first thought was that I should probably reel the fish in slower.  I was wrong.  According to the scientists I talked to it would take hours or even days for the fish to adjust to such a dramatic change in pressure.

The problem with fizzing yellow perch is that their internal organs are arranged somewhat differently than other fish.  Like their cousins the walleye, the vital organs in perch are highly compacted and very close together.  There is a very high likelihood of puncturing other vital organs when fishermen attempt to fizz yellow perch. (Click on the diagram to the left to see a close-up of their internal organs.) There are research studies that show fish in the perch family are much more likely to die after fizzing. There may be some fishermen who are experienced and knowledgeable enough to fizz a perch properly, but even after 45 years of fish-handling experience, I’m not willing to take the risk.

So, what’s a fisherman to do?  Yellow perch are fun and easy to catch and absolutely delicious to eat.  People all across the United States fish for perch through the cold-weather months.  You might even call it a national winter pastime.  Still, most of us don’t really want to kill fish except the ones we plan to eat.  Fortunately, according to the experts, there are some practices we can use to insure more fish stay alive.

First off, if we see that most of the fish we are catching out of deep water are undersized, there’s really no reason to keep fishing there.  If you’re like me, you’re usually out to catch the biggest fish you can find.  In the winter months prior to the spawn, Chesapeake Bay perch can be found in depths from 20 to 65 feet.  A fish caught from 20-30 feet is a lot more likely to survive than one caught deeper.

If we catch a fish with an over-extended swim bladder that we don’t want to keep, it’s better to just let it go quickly so it can swim back down.  Research shows that tissue around the swim bladder is often capable of withstanding a pronounced increase in size for a few minutes.  Most fish can re-submerge if released within a few seconds.

When releasing yellow perch, we also need to employ the same careful catch techniques we would with other species.  These include as little handling of the fish as possible, keeping the fish wet when removing the hook, not touching sensitive areas like the eyes and gills, and cutting the line on deeply hooked fish.  More information about catch and release techniques can be found on Maryland’s Careful Catch website.  You might also want to check out the Careful Catch Facebook page to read up on happenings around the country.

I only fished once this past week, getting out for a few minutes with my friend Rich up near Owens Landing.  Despite very cold weather and strong winds, we found nice perch in water that was 20-25 feet deep.  Although we were slipping and sliding around on snow and ice on the deck of the boat, and constantly fighting ice build-up in our line guides, we managed to land a nice limit of yellow perch in relatively short order.  This week’s cold weather has iced over most of the upper Bay ramps, so fishing from boats is going to be tough for a while.  Fortunately, there are plenty of docks and accessible shoreline in the upper bay area where we can still catch fish.  Most have access to varying depths, so we can adjust our casts to look for the keepers and pull off the little guys in deep water.  Be careful and good luck if you get out there!