Chesapeake Bay Tidal Waters:
Fisheries Services' 2009 Year In Review
Resident Species Project
The Resident Species Project is charged with monitoring and assessing recreationally important tidal fish species that do not migrate out of state waters. These species include white perch, yellow perch, and channel catfish. Resident Species Project conducts fyke net surveys during the spring and a trawl survey during December – February.
Results from our fieldwork and assessments indicate that quality-sized channel catfish abundance has continued to increase. Medium-sized channel catfish that were spawned over the last few years should be growing into respectable sizes. In general, it takes channel catfish about 4 years to reach 16”. Populations have rebounded from low levels, but bay-wide recruitment has been poor since 2006. Since reproduction has been generally poor recently, populations will probably stabilize at slightly lower levels. Interestingly, channel catfish reproduction in the Choptank River has been very good and a fyke net survey indicates that the population has been growing nearly linearly since 2004. Anglers and commercial fishermen have reported continually increasing numbers of flathead catfish in the Susquehanna River. These voracious predators are non-native and considered an invasive species. Studies in other areas where flathead catfish have been introduced show that they can drastically alter the native and naturalized fish communities.
White perch fishers experienced a very good summer and fall during 2008 and a slightly less productive 2009. White perch were last assessed during 2008. The assessment showed that populations were very healthy and fishing mortality was low. Recruitment in 2007 was very good, poor in 2008 and about average in 2009. Therefore, the population should be fairly stable over the next few years. The length structures of the populations that we sample also indicate that the abundance of larger white perch should continue to increase in 2010.
Yellow perch runs during the spring of 2009 were very good in spite of the temperamental spring weather. An updated assessment of upper Bay populations indicated that abundance is decreasing due to below average reproduction during 2006 -- 2009. Fishing mortality was estimated to have decreased since 2004, and currently is at low levels. Interestingly, there were more reports of summertime anglers having very good success in finding keeper yellow perch. Spring fishing during 2010 should be very good in the upper Bay and in the Choptank River as strong year-classes produced in the early 2000’s grow to large sizes. We expect anglers to have about the same success as last year with possibly fewer undersized yellow perch to sort through.
Anglers are reminded that there is an on-line yellow perch angler creel survey on the DNR web page. Simply log in and provide information on where you fished and what yellow perch you caught. The information has proved very useful in our assessments.
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Fish Ecosystem Program
Increasing development of natural areas to suburbs and cities has been identified as a threat to the Chesapeake Bay watershed because converting farms, forests, and wetlands to urban land (residences and commercial property) is associated with diminished water supply, erosion, sedimentation, thermal pollution, and excess nutrients and toxic compounds that pollute water. There is a direct relationship between increased urban land cover with declining water quality and fish habitat. The amount of land development has increased in Maryland and more land was developed per person between 1973 and 2000. Maryland’s Department of Planning estimated that 8% of Maryland was urban in 1973 when its population was 3.9 million people. By 2000, Maryland’s population increased to 5.3 million (an increase of 35%) while urban land doubled to 16%. By 2030, 6.7 million people are expected to live in Maryland and will put pressure on remaining rural lands and fish habitat that depend on it.
In 2003, Maryland’s Department of Natural Resources, Fisheries Service started a program to understand the relationship of land development and fish habitat in Chesapeake Bay to plan ahead for fisheries as natural areas are converted to suburbs and cities. Land use planning is largely under local control and is often conducted on a project-by-project basis that does not balance cumulative watershed-wide impacts of development with the fishes’ need for clean water. We are working to define how much development can occur in a watershed before fish habitat and fisheries are degraded. We hope that this information will be used to make land use decisions that consider the needs of fish.
Our studies indicate when impervious surfaces (a measure of development which are surfaces that do not absorb water such as rooftops, roads, sidewalks, parking lots and compacted soils) cover 10% or more of a watershed (indicating suburban development), fish habitat degrades and fish populations decline. Stream and tidal waters become less and less healthy for spawning of anadromous fish like white and yellow perch, alewife, and blueback herring. In brackish tributaries during summer, oxygen levels in bottom habitat fall directly with the amount of development, as do fish and crab abundance in these moderate-to-deep waters. Fish and crabs are pushed into smaller areas of shallow water as more bottom habitat is lost. We do not see the same response of oxygen in tidal tributaries that have mostly freshwater, but we seem to see decreases in fish abundance at high levels of development. We are focusing more on fresh-tidal areas to try and understand what other development-related factors may cause fish become less abundant.
During early March through early May, 2009, citizen volunteers assisted us by sampling anadromous fish eggs and larvae, and water quality in several tributaries of the Bay. Fine mesh drift nets, designed to capture drifting eggs and larvae in streams, and were deployed in the flowing waters of Mattawoman and Piscataway creeks. Biologists towed fine-mesh plankton nets from boats in the tidal portions of these creeks as well as Nanjemoy Creek and Magothy River to document the presence or absence of larval yellow perch in late March through April.
During summer 2009 (July – September), we mainly concentrated on studying fish in fresh-tidal Bay tributaries. We sampled Northeast, Bush, Middle, Gunpowder, and Tred Avon rivers and Mattawoman, Nanjemoy, and Piscataway creeks. Impervious cover in these systems spanned from about 1% to 25% of watershed area. Four evenly spaced sample sites were sampled every two weeks in each tributary. Trawling and seining were used to sample fish, and dissolved oxygen, pH (acidity), conductivity, and salinity was measured at all sites.
We prepare a report of our findings annually as a requirement for federal funding. This funding is possible because of additional taxes on fishing and boating supplies. Throughout 2009, we met with the public, as well as local, state, and federal agencies to explain our concerns about the future of fishing and how development affects it.
We will continue in 2010 to sample these tidal tributaries to further explore the effects of impervious surface on tidal-fresh habitats and develop a better understanding of the processes that impact the fish community in these areas.
The Fish Passage Program has spent the 2009 year hard at work! Although no blockages were removed this past calendar year, important progress has been made to ensure productive years in 2010 and 2011.
Most notable in 2009 was the collaboration with the non-profit dam removal and river restoration group – American Rivers. Working with American Rivers and other partners, we received an American Recovery and Reinvestment Act (ARRA) grant from the National Oceanic & Atmospheric Administration (NOAA) for over $4 million dollars. Our grant was 1 of 50 projects funded from over 800 nationwide grant applications. The ARRA money will be used to remove 2 large dams on the Patapsco River in 2010. For more information on the ARRA project visit www.noaa.gov/recovery/ and locate Maryland/Patapsco River on the interactive map.
Working with the National Resource Conservation Service, Chesapeake Bay Trust, and Fish America Foundation, the Fish Passage Program also secured money for the removal of White Hall dam on Little Falls River, a tributary to the Gunpowder River in Baltimore County. Project partners provided more then $250,000 for the dam removal which will reopen over 25 miles of river and improve habitat for naturally reproducing trout. In addition, the Fish Passage Staff is actively coordinating 5 more dam removal projects which we hope to complete in the future.
This past spring the Fish Passage Program conducted a monitoring study to document current migratory fish spawning locations. The 2009 study sampled sites from locations originally identified in a similar survey conducted in the late 1960’s and early 1970’s. Current migratory fish spawning locations were documented by observing adult fish including herring, shad, and perch at select river locations across the State. Sampling nets with extremely fine mesh were deployed to capture larval fish and fish eggs. Samples were taken back to the lab for identification. Collection of larval fish or eggs proves that adult fish were present at/near the sampling site and successfully spawned. Results from this year’s samples were compared to previous results. We found an expansion of hickory shad spawning areas while yellow and white perch sites have declined. Overall, the number of sites where herring have been observed has remained relatively constant. Our results indicate that migratory fish are successfully utilizing habitat reopened by past fish passage projects and dam removals.
Check out our website to find more information about dam removal projects and the 2009 spring monitoring results.
American and Hickory Shad and River Herring
The Alosa project targets American and hickory shad and river herring (blueback and alewife herring). Monitoring for these species has occurred in several major tributaries including the Nanticoke and Susquehanna rivers but stock assessment data is also analyzed from the main Bay and other tributaries.
Data collected from this project determines adult American shad stock status and biological reference points for all four species in Maryland. This project also assesses the status of American shad restoration projects in select tributaries. Successful return of Alosa adults, reproduction, and juvenile survival are an indicator of ecosystem health, in the Bay and the ocean.
Adult American shad and river herring have declined to very low levels in the main Bay and tributaries and efforts to restore these species has had little effect, although there were increases for American shad abundance in 2009. The cumulative causes for the overall decline include overfishing, predation, and loss of habitat and ocean bycatch.
Hickory shad abundance remains high in established rivers including Deer Creek and the data collected from some of these fish shows a very good distribution of ages and low mortality. Hickory shad survival may be better than the other Alosa species because of their very early spawning season and their tendency to hug the Atlantic Coast, possibly reducing their exposure to predation and commercial fishing operations.
American Eel Program
Over the last 10 years Maryland’s commercial American eel fishery ranks #1 among all Atlantic coastal states, accounting for more than 40% of the total American eel harvest. Average annual eel landings over this period were approximately 300,000 pounds. American eels are harvested bay wide in both the main stem and nearly all tributaries in Maryland’s tidal portion of the Chesapeake Bay. Over 95% of the eels are captured with eel pots.
Since 1997, DNR Fishery Service has conducted an American eel study. Major components of this study include collection and analysis of harvest data from the commercial eel fishery, monitoring of the eel fishery through representative subsampling of commercial catches, the development of American eel size and age structure in selected tributaries of the Chesapeake Bay, an eel pot study in the Sassafras River, and an annual young of year abundance survey in the Coastal Bays.
Results to date indicate that the juvenile eel index in 2008 and 2009 catches dipped slightly below the ten year average after marking a ten year high in 2007. The overall ten year juvenile index, although quite variable, shows no apparent trend. Yellow eel relative abundance indices based on commercial landings continued to show a positive trend through 2008. Commercial eeling effort in 2008 increased approximately 10% from 2007, but still remained 30 % less than a seventeen year average. The yellow eel relative abundance index from our eel pot sampling continued a positive trend in 2009 with catches being significantly higher than 5 of the previous 6 sampled years.
DNR also participates in multi-state management of the American eel through multiple technical committees established by the Atlantic States Marine Fisheries Commission (ASMFC). ASMFC, which was formed 65 years ago by the 15 Atlantic coastal states, has management authority for 22 inter-jurisdictional species groups.
Summer Migrant Species
Weakfish, bluefish, Atlantic croaker, summer flounder and spot are all very popular migratory sport fish in Maryland. Fisheries Services has conducted summer pound net sampling since 1993 to track population trends in summer migrant species. DNR biologists examined fish captured in commercial pound nets, from cooperating watermen, from late May through September from 1993-2009. Beginning in 2009 data from fish harvested in Maryland was also collected at seafood dealers for these species. Data collected from these surveys as well as commercial landings, estimates of recreational landings and knowledge of each species life history are used to evaluate and manage these species in Maryland. All of these species migrate in and out of Maryland waters and are managed on a regional basis, usually their entire range along the east coast of the Atlantic Ocean.
The Atlantic croaker population has been high for several years. Maryland recreational anglers landed between 825,578 and 2,674,800 fish from 1997 to 2007. All eleven of those years were above the long-term average of 742,222 according to estimates by the National Marine Fisheries Service. In 2008 the recreational harvest estimate decreased slightly to 689,184 fish. The average length of croaker examined from the pound net survey in 2009 was 12.5 inches; this was the highest average length of the 17-year time series. Atlantic croaker from seafood dealer sampling averaged 11.75 inches and 0.8 pounds. Fish aged from the 2008 survey were between 1 and 11 years old. The croaker population tends to have cyclic patterns of abundance, with several high years followed by a decline to several low years followed by recovery. The recent high abundance period has endured longer than those of the past. An evaluation of the population by the Atlantic States Marine Fisheries Commission (ASMFC) is currently being conducted to gain a better understanding of the current health of the croaker population on the east coast, and should be completed this spring.
Weakfish have experienced a sharp decline in numbers coast wide. Recreational catch estimates by the National Marine Fisheries Service (NMFS) for Maryland fell steadily from 475,348 fish in 2000 to 493 fish in 2006, and was only 2,590 weakfish in 2008, well bellow the long term average of 326,291 fish. The 2009 average length for weakfish from the pound net survey was 10.3 inches, the lowest average of the 17 years of the survey. Only six weakfish were measured during seafood dealer sampling. Fish aged from the 2008 pound net survey were all 3 years of age or younger. These findings agree with the recently completed ASMFC coast wide population assessment, which found the weakfish population to be depleted, and being made up of mostly small younger fish. The recent decline in abundance has occurred despite regulations designed to increase the population. This was determined to be caused by an increase in natural mortality. Expect to see continued low catches of legal size weakfish and more restrictive recreational and commercial limits in 2010. The new restrictions will be put in place to help protect the remaining population, until natural mortality returns to lower levels and the population can rebuild.
Spot is a short-lived species with high growth rates. This type of fishery tends to be more variable from year to year, and more dependent upon the number of young of the year spot and their survival to adulthood. Juvenile indexes have been lower in recent years than the long-term average while recreational catch estimates in 2007 and 2008 were above the long term average of 1,716,025 spot per year. Spot from the 2009 pound net survey were generally smaller than in previous years. The percent of spot over 10 inches in the pound net samples has been decreasing for the past several years. (less than one percent in 2008 and 2009). Spot not only provide for fun recreation and tasty meals, but also provide quality forage for more popular sport fish such as weakfish, bluefish and striped bass.
Bluefish recreational harvest estimates were high through most of the 1980’s and have since been somewhat stable at a lower level. Average length of bluefish from the pound net survey in 2009 was 10.4 inches, similar to that of 2008. These were both a decrease from the above average mean length of 12.5 inches in 2007. Maryland’s portion of the Chesapeake Bay is primarily a nursery area for bluefish, with a small and variable number of larger fish migrating here for anglers to catch. It is not fully understood why larger bluefish migration into the Bay is so variable, but availability of prey is most likely one of the main factors. The latest coast wide population assessment indicated the population was not overfished and overfishing is not occurring.
Summer flounder average length from the pound net survey was 14.5 inches in 2009, a little above average for the 17 year survey. A larger percentage of flounder were above the minimum recreational size limit in 2009 compared to 2008. I would expect higher landings for 2009, due to the presence of larger fish in the 2009 pound net survey, however an increase in size limit for 2009 may have kept the landings from increasing dramatically. The 2006 coast wide stock assessment indicated the population was not overfished but overfishing is occurring. This is the reason higher size limits and lower creel limits have been established, to reduce the number of fish being removed from the population.
Black drum, red drum, Spanish mackerel and spotted seatrout are also examined by the survey. Spanish mackerel is the only one of these species encountered on somewhat regular bases in the southern portion Maryland’s Chesapeake Bay, because it prefers higher salinities. Maryland tends to be on the northern end of the other three species range, but they are generally available to anglers here in the summer months.
American Shad and Hickory Shad Restoration
The project goal is the creation of self-sustaining populations of American shad and hickory shad through introduction of hatchery-produced larvae and juveniles. Target watersheds include the Patuxent River, Choptank River and Nanticoke River. DNR surveys indicated severely depleted shad stocks in these watersheds and lack of viable spawning populations. DNR’s shad restoration project is a collaborative effort. Nanticoke River restoration work is a cooperative program with Delaware Division of Fish and Wildlife. Mirant LLC also cooperates with DNR restoration projects through their Chalk Point Aquaculture Center.
Patuxent River American Shad
Hatchery origin juveniles were routinely captured during the early stages of the restoration effort, but no wild juveniles were present in any collections from the river until 1998. Since then, wild juvenile abundance has generally increased over the years. Adult composition has also shifted toward wild fish. In 2009, hatchery fish represented only 32% of the recaptured adults. This number is unchanged from 2008 recaptures. Catch and release anglers might catch an American shad or two along the two-mile stretch below Queen Anne Bridge. If you are traveling by boat, be aware of the tide. Boating traffic is only advisable on a flooding or high tide. There are too many submerged trees above the 4H Park for boat traffic, but kayaks or canoes can continue upstream.
Choptank River and Marshyhope Creek American Shad
DNR recaptured 13 adult American shad in 2009. Of those 13 shad captured, 70% were hatchery fish marked and stocked as larvae (57%) and early juveniles (43%).There were relatively few adult American shad present in the Choptank River in 2008. Even though the river has been stocked since 1996 at a low level, intensive American shad stocking did not commence until 2002. It appears now that hatchery adults are beginning to return as adults to spawn in greater numbers.
Marshyhope Creek restoration began in 2000 and it is too early to accurately assess the progress at this time. In 2008, 15% of recaptured American shad adults were of hatchery origin. Excellent American shad larval survival and high juvenile abundance documented in 2002 and 2003 should result in large numbers of returning adults beginning in 2009. In 2009, 57% of recaptured American shad adults were of hatchery origin. This is encouraging, however there were only 7 adults recaptured in the spring survey.
Catch and release fishing for American shad might yield a few strikes in 2010 on both the Choptank River and Marshyhope Creek. Choptank River anglers should concentrate their efforts from the Greensboro boat ramp downstream to Depue Landing Road. Marshyhope Creek is likely to produce some fish from a mile above the Federalsburg Bridge (Rt.306) to several miles downstream. Be aware of the tide if traveling by boat above the Federalsburg boat ramp. Larger boats will not be able to pass under the bridge on extremely high tides. However, a large pool 0.78 miles above Federalsburg may be worth a well planned trip by small boat.
Hickory Shad Patuxent River
Analyses of 2009 samples indicate that hatchery fish comprised 38% of the adult population. Hatchery contribution to the adult stock has been below 20% since 2004. This rise in hatchery contribution may be due to successful early juvenile stockings since 2005. Since the population seems to be stable and self-sustaining at this time, we have decided to discontinue stocking hickory shad in the Patuxent River. We will continue to monitor the adult population to assess natural reproduction.
The Patuxent River should provide many opportunities for hickory shad catch and release fishing in 2010. Sampling for adults in 2009 indicated a large population of adult hickory shad. Hickory shad should begin to arrive in early March and will peak in early to mid-April when water temperatures rise above 55 degrees. The highest concentration of shad should begin about a mile or so below Queen Anne Bridge and continue above the bridge to Route 50. While there is some access by land, a small boat, kayak or canoe would enable the angler to cover more water. If you are traveling by boat, be aware of the tide. Boating traffic is only advisable on a flooding or high tide. There are too many submerged trees above the 4H Park for boat traffic.
Hickory Shad Choptank River
The Choptank River indicates a positive restoration response. Adult captures from 2004-2007 indicate hatchery contribution below 30%. In 2008, hatchery contribution to the adult population was 35%. This slight increase is due to stocking early juveniles in 2002. In 2009, hatchery contribution to the adult population was 59%. We predict that the proportion of hatchery fish will continue to increase based on stocking large numbers of early juveniles from 2005 to 2009. Choptank River stocking will continue in 2010.
Choptank River catch and release shad fishing should be excellent in 2010. Hickory shad are normally caught in the main stem from Red Bridges down to Greensboro. Tuckahoe Creek has produced some decent hickory shad fishing in the past, principally below Crouse Mill Dam. However, anglers have reported reduced success there over the last several years.
Hickory Shad Nanticoke River
Most of the hickory shad habitat in the main stem Nanticoke exists in Delaware. Marshyhope Creek is the best opportunity for Maryland anglers to catch and release hickory shad in this watershed. Migrating shad will be concentrated in the area from Federalsburg up to the Maryland-Delaware line. The Marshyhope Creek currently has a remnant wild spawning population of hickory shad. Stocked fish are also beginning to return to this watershed. In 2009, data from the adult electro- fishing survey determined that hatchery contribution to the adult population was 16%. Hatchery contribution to the adult population in 2008 was 25% and 13% in 2007. The combination of the remnant wild population and hatchery origin adults should provide some angling opportunities in 2010. Marshyhope Creek is likely to produce some fish from a mile above the Federalsburg Bridge (Rt.306) to several miles downstream. Be aware of the tide if traveling by boat above the Federalsburg boat ramp. Larger boats will not be able to pass under the bridge on extremely high tides. However, a large pool 0.78 miles above the bridge may be worth a well-planned trip by small boat.
Atlantic sturgeon restoration
Fisheries Service has teamed up with U.S. Fish & Wildlife Service (USFWS), Mirant LLC and University of Maryland to restore spawning populations of Atlantic sturgeon to Maryland’s Chesapeake Bay tributaries. This prehistoric fish historically spawned in most of Maryland’s larger tidal rivers. The Atlantic sturgeon is a species like no other in the Chesapeake Bay. Sturgeon originated 120 million years ago and continue to exist today. They can live more than 60 years and the largest Atlantic sturgeon specimen ever recorded reached 14 feet and 811 pounds. Virtually the entire Maryland spawning stock was depleted during a period of over-fishing in the late 1800s and it has not recovered to this day. There is still a small spawning population in Virginia’s James River. Since Maryland has no documented spawning population, our restoration strategy is based on stocking hatchery fish to evaluate habitat suitability and reintroduce fish of “local” origin that will return to spawn in Maryland upon reaching maturity.
Maryland Sturgeon Reward Program
Even though there are no documented spawning populations, Maryland waters do support migrant fish that were spawned in other East Coast tributaries. These fish move great distances along the Atlantic Coast while foraging for food. Wild, migrant Atlantic sturgeon are collected from commercial fisherman in Maryland waters as part of the Maryland DNR and USFWS- Maryland Fishery Resources Office (USFWS-MFRO) jointly operated Maryland Sturgeon Reward Program. A monetary reward is offered for the report and delivery of live Atlantic sturgeon. The Maryland Sturgeon Reward Program is used to monitor sturgeon populations in Maryland’s Chesapeake Bay and provides suitable specimens for introduction into the captive brood stock population. Most of these migrant fish are sub-adult age (three to eight years). Female Atlantic sturgeon do not reach maturity for 15-20 years in the Chesapeake region. Therefore, these fish will be cultured for many years before they
are old enough to spawn in the hatchery.
While we are culturing the brood stock to maturity, we are busy acquiring the tools, technology and methodology that will be required for such an ambitious undertaking.
We are attempting to culture a captive brood stock, which will be used to produce hatchery origin sturgeon for release into Maryland tributaries. Hatchery-origin larvae and juveniles should return to the stocked tributaries to spawn. Experimental stocking will be used to evaluate habitat suitability in target tributaries. The captive brood fish originate as Chesapeake Bay migrants. These fish are foraging in Maryland waters but their origin is likely from other systems. Genetic studies conducted for DNR by the USFWS Northeast Fishery Center in Lamar, Pennsylvania (USFWS NFC) indicate that sturgeon captured in Maryland’s Chesapeake Bay predominantly originate from the Delaware River, James River and Hudson River.
We continued experimental trials in 2009 at Manning State Fish Hatchery, University of Maryland Aquaculture Restoration and Ecology (AREL) laboratory (Cambridge, MD), and Mirant Potomac River Generating Station (Alexandria, VA) to refine Atlantic sturgeon culture procedures. Yolk-sac larvae were obtained from a Canadian source (Acadian Sturgeon and Caviar Company, Saint John, NB, Canada) for this purpose. One goal was to identify potential stumbling blocks to successful early life stage culture at our facilities. The other goal was to construct recirculating and flow through aquaculture systems so we will have the ability to culture fish throughout the year under optimal conditions. Manning Hatchery was originally designed as a flow-through facility so it is a major departure to transition into recirculating systems.
Maintaining water quality is a challenge in this type of culture and the Canadian-source fish allow us to troubleshoot systems and techniques before we have the ecologically valuable larvae and juveniles that we hope to produce from our captive brood stock. After several years of culturing Canadian fish, we feel we now have the ability to successfully culture larvae at our facility. Operation, improvement and refinement of recirculating systems at Manning will continue to evolve.
Atlantic sturgeon are believed to imprint on their natal rivers, allowing them to return to spawn upon maturity. The mechanism and timing of this homing behavior, or fidelity, are not fully understood at this time. It is critical that any fish stocked as larvae or juveniles will imprint to the target tributary, so that they may successfully return to spawn. One way to improve the chances that appropriate imprinting will occur is to culture larvae and juveniles in water from the target tributary. Development of streamside culture techniques could insure that any fish stocked will imprint to their river of “origin” and return there to spawn when they reach maturity. This technique is especially important since Atlantic sturgeon take fifteen to twenty years to mature. This extended maturity schedule means that any imprinting failure will not be detected for up to two decades.
In order to address this issue, we conducted an experimental trial with the Mirant Potomac River Generating Station to investigate the potential for streamside Atlantic sturgeon culture. Mirant contributed significant financial resources, construction manpower and cooperation to implement the culture operation. Mirant has agreed to financially and operationally support the facility through at least 2013. This power generation plant is located on the Potomac River in Alexandria, Virginia. The Potomac River is a likely candidate as a target tributary for Atlantic sturgeon restoration so this partnership was a good fit. This system is a flow-through design built to utilize the Potomac River as a water source. In 2008- 09, several design changes were made to this facility in attempt to control sedimentation issues. Many of these changes included the installation of different filtration systems which ultimately proved unsuccessful at improving water quality. The proposed installation of a drum filter in 2010 most likely will alleviate the sedimentation problem and improve water quality dramatically. Mirant will provide up to $325,000 over the next four years to support restoration activities of Atlantic sturgeon.
We are utilizing microsatellite DNA analysis to determine relatedness and origin of the brood stock. This information will be used to create a brood stock management plan to insure that we are producing progeny that will be genetically fit. This work is a cooperative effort with USFWS-NFC.
Blood Plasma Analysis
We are cooperating with Virginia Institute of Marine Science (VIMS) and the USFWS Bozeman Fish Technology Center to evaluate steroid levels in Atlantic sturgeon blood. This research could indicate the potential to assess maturity through blood analysis. This would be a useful tool to identify captive and wild fish that might be reaching sexual maturity and could also improve spawning protocols in the hatchery.
DNR is investigating whether cryogenically preserved sturgeon sperm can be used to successfully fertilize eggs. Frozen sperm could be stored indefinitely and a genetically diverse collection could be maintained on site at the culture facilities. If this technique can be perfected, it will provide greater flexibility in population restoration, culture and spawning work. Cryogenic preservation work is conducted in partnership with University of Maryland Crane Aquaculture Facility (College Park, MD), USFWS Warm Springs Fish Technology Center (Warm Springs, Georgia) and USFWS-NFC. We will continue to refine this technique in future years. The goal of the research is to refine cryopreservation techniques and create an archive of genetic material that will be redundantly stored at USFWS-Warm Springs, USFWS-NFC and Maryland DNR’s Manning State Fish Hatchery.
On July 15, 2009, eight Atlantic sturgeon males cultured at Mirant Mid-Atlantic’s Chalk Point Generating Station were hormonally-induced to spawn with Luteinizing Hormone-Releasing Hormone analogue (LHRHa). These males were all selected after a laparoscopic evaluation determined their state of sexual maturation. The sturgeon were evaluated 24 hours post-injection. Of the eight males injected, three males successfully spermiated. Milt was extracted with Tygon® tubing attached to a 60 ml syringe. The males produced between 36 and 161 ml of sperm. These samples were packaged on ice, oxygenated in plastic containers and transported to UM-Crane Aquaculture Facility and analyzed for motility, osmality, pH, concentration and viability. The samples proved to be of high quality with viabilities ranging from 84% to 90% and have been cryogenically preserved. Similar trials will be conducted in 2010. These trials were conducted within the jurisdiction of the USFWS Aquatic Animal Drug Approval Program (AADAP) INAD #8391 and #8061.
Laparoscopic surgery is being performed to assess sexual maturity. In this process, an endoscope is inserted through a small incision in the body cavity. This minimally invasive procedure monitors the progress of sexual maturity without imparting undue stress to the animal. Perfecting the laparoscopic surgery procedures used to determine sex and maturity is one goal of the Maryland Atlantic Sturgeon Restoration program.
In November 2009, we examined the stress levels on individual sturgeon associated with this minimally invasive surgery. This cooperative study was performed by staff from DNR Fisheries Service Anadromous Restoration project, DNR Fisheries Service Fish & Wildlife Health project (Cooperative Oxford Laboratory), AREL and Mirant. The study required laparoscopic surgeries to be performed on 60 Atlantic sturgeon cultured at the Mirant Chalk Point Generating Station. Stress levels were analyzed by quantifying the cortisol levels in each fish at two and twenty-six hours post-surgery. Cortisol is usually referred to as the "stress hormone" as it responds to stress and anxiety. Initial results are very encouraging, as the cortisol response was barely elevated at two hours post-surgery and back to normal by 26 hours. Analysis of data obtained from this experiment will continue in 2010.
Captive Brood Stock Diet
Techniques to train wild-caught sturgeon to eat commercial fish diets in the hatchery and evaluation of various nutrient strategies for larval and juvenile sturgeon were conducted in 2009. The University of Maryland Aquatic and Restoration Ecology Laboratory (AREL) performs this research at the Horn Point campus in Cambridge, Maryland.
DNR is developing tagging or marking techniques for larval and juvenile hatchery-origin Atlantic sturgeon. Several Atlantic sturgeon marking techniques were evaluated in 2008-09. Technologies investigated include radio frequency identification tags (RFID) (Biomark Inc., Boise, Idaho), immersion in chemicals that stain bony and cartilaginous tissues and implantation of silicon-based elastomeric liquids (Northwest Marine Technologies Inc., Shaw Island, Washington).
RFID tags are commonly used in fisheries research. The limiting factor to this technology is that only sturgeon longer than approximately six inches in length can be implanted. Calcium-staining is an excellent methodology to batch mark large numbers of larval fish. We do not know how long these marks can be identified using non-lethal assessment techniques. Chemical marking research will continue in future years. Elastomers are injected just beneath the skin. The liquid cures to a solid that is visible beneath translucent tissues. In 2007, sturgeon held at Manning Hatchery were evaluated for elastomer mark retention. After one year, marks were still visible using a Se-mark™ detector indicating the potential for future use. Future work will investigate using genetic analysis to identify markers that are specific to hatchery fish.
The Fisheries Service Atlantic Sturgeon Restoration Project is a great example of the importance of cooperative partnership efforts. This project utilizes the resources and expertise of the federal government, state government, university researchers and commercial enterprises to reach a common and mutually beneficial goal. Restoration of this historically and ecologically important species cannot occur without the contribution of all the partners.
Funding is now the biggest obstacle to Atlantic sturgeon restoration in Maryland. It is difficult to obtain continuous funding over several decades for a single species. Sturgeon researchers from Virginia and Maryland have teamed up to create the Chesapeake Bay Atlantic Sturgeon Conservation Program. The purpose of this group is to create a comprehensive conservation strategy for Atlantic sturgeon in the entire Chesapeake Bay and work to obtain financial support to conduct the necessary research. Cooperators include DNR, University of Maryland, Mirant, USFWS, VIMS, Virginia Commonwealth University, and the National Oceanic and Atmospheric Administration. Our focus in the near future will be to secure long-term funding in order to continue this important work.
Fish Health / Mycobacteriosis
The Fish and Wildlife Health Program (FWHP) continued its study of Mycobacteriosis, a bacterial disease that has been present in the striped bass population since at least the mid 1980s. Prevalence of this disease in fish collected from pound nets has increased from 25% in 1998 to 60% in 2008, but has leveled off since 2004. Data analysis of fish collected in 2009 is underway. This disease is first evident in age-1 striped bass and increases in both male and female fish with age until at least age-6. Lesions caused by this disease are most evident on 4 to 7 year old fish (approximately 18-28”). Mycobacteriosis is not limited to the Chesapeake Bay, although the prevalence of this disease (and external lesions in general) is significantly lower in the migratory spawning stock.
In 2007 the Maryland Department of Natural Resources (MD DNR) and the Virginia Institute of Marine Science (VIMS) began a cooperative tagging study to estimate the impact of Mycobacteriosis on the striped bass population in both the upper and lower reaches of the Chesapeake Bay. VIMS initiated this tagging study in 2005 to track the progress of the disease in the Rappahannock River, Virginia. During the spring and fall of 2007 MD DNR and VIMS tagged and released more than 3,000 striped bass with a unique bright green colored tag. The bright green tags are marked with either “VIMS” or “MD DNR” and include a toll free number (1-866-845-3379) to report the fish (Photo 1). If you catch a striped bass with a green MD DNR or VIMS tag hold onto the fish and report it immediately so that fish health biologists can arrange pickup and analyze the skin and internal organs for disease. 3,423 fish have been tagged by MD DNR since 2007 with 125 of these fish being reported back.
For best results, it is important that fish are reported promptly after capture, kept intact (DO NOT FILET) and chilled with ice (DO NOT FREEZE). A $20 reward is available for each fish that is picked up by DNR biologists. If you choose not to hold the fish, we ask that you clip the tag off the fish close to the body and call the number listed. A $5 reward will be paid for the return of each green tag and information on when and where the fish was caught. This study will continue through at least 2009.
Handling and consumption of diseased fish is a continued concern for both anglers and commercial watermen. The bacteria that cause this disease in fish do not pose an unusual danger to fishermen, but it is possible to contract an infection by handling sick fish, particularly if you have open cuts on your hands or if a fish spine penetrates your skin. Therefore, we recommend simple precautions like handling fish with gloves and washing hands frequently. Having a bottle of the waterless anti-bacterial hand wash on hand is a good idea. Although the Department of Health and Mental Hygiene has found no association between consumption of diseased fish and human mycobacterial illness, MD DNR recommends that anglers avoid consuming any fish with visible lesions.
Shortnose Sturgeon Health Study
The Fish and Wildlife Health Program continues a health study of the shortnose sturgeon, which began in 2006. Like its larger relative the Atlantic sturgeon, the shortnose sturgeon was once numerous in the Chesapeake Bay, but over fishing and habitat loss have greatly reduced the population size and since 1967 the shortnose sturgeon has been listed as endangered. Little is known about this fish in the Chesapeake Bay and because it is endangered, great care must be taken when handling and examining fish. Traditional techniques to identify the gender and collect samples of the internal organs by sacrificing the fish are not an option.
Therefore the first goal of this study was to adapt the use of laparoscopic surgery, which is effective and minimally invasive, to identify the sex and examine internal organs using captive sturgeon. Chemical analysis of blood samples provides clues on the general health of fish and reproductive hormones can be measured. Tissue samples collected allow biologists to determine the gender of fish, if the fish are mature or not and if any reproductive health problems are present. The second and current phase of this study is to use laparoscopy to examine shortnose sturgeon from the neighboring Delaware River and from fish maintained in captivity as a means of comparison to Chesapeake Bay sturgeon.
The population of shortnose sturgeon is much larger in the Delaware River and some of these fish enter the Chesapeake Bay through the C&D canal. In addition to the health studies, a genetic study will be conducted to determine if a distinct Chesapeake Bay population exists or if Delaware River fish populate the Bay. To date, almost 200 captive and wild shortnose sturgeon have been examined providing a wealth of new information. The final phase of this study will be to use laparoscopy and other techniques to assess the health of shortnose sturgeon during of a broader survey to determine the abundance and distribution of this species in Chesapeake Bay.
Striped Bass Program
The spring, 2009 spawning stock survey indicated that there were 15 age-classes of striped bass present on the Potomac River and Upper Bay spawning grounds. These fish ranged in age from 2 to 15 years old. Age 6 striped bass from the 2003 year-class were the most abundant component of the male striped bass spawning stock. Age 13 (1996 year-class) and age 9 (2000 year-class) females were the major contributors to 2009 total female abundance. Age 8 and older females comprised 88% of the female spawning stock in 2009.
The 2009 striped bass juvenile index, the annual measure of striped bass spawning success in Chesapeake Bay, is 7.9. This is slightly below the average long-term average of 11.7, but more than twice last year’s value. During the survey, biologists identified and counted more than 35,000 fish of 49 species, including over 1,000 young-of-year striped bass.
Variable reproductive success is a normal condition of striped bass populations. Typically, several years of average reproduction are interspersed with occasional large and small year-classes. Large year-classes in successful spawning years like 2001, 2003 and 2005 bolster the population by offsetting less successful years. The largest year-class ever measured occurred in 1996.
DNR biologists have monitored the reproductive success of striped bass and other species in Maryland’s portion of the Chesapeake Bay annually since 1954. Twenty-two survey sites are located in the four major spawning systems: Choptank, Potomac, and Nanticoke rivers, and the Upper Bay. Biologists visit each site monthly from July through September, collecting fish samples with two sweeps of a 100-foot beach seine. The index is calculated as the average catch of young-of-year fish per sample. The underlying spawning stock is still healthy and is watched closely by DNR biologists and monitored in partnership with other coastal states through the Atlantic State's Marine Fisheries Commission. For more information, go to www.dnr.state.md.us/fisheries/juvindex/index.html
During the 2009 trophy season, biologists intercepted 322 fishing trips, interviewed 747 anglers, and examined a total of 216 striped bass. The average total length of striped bass sampled was 913 mm TL (35.9 inches), and the average weight was 7.9 kg (17.4 lbs). Most fish sampled from the trophy fishery were between eight and thirteen years old. The 2000 year-class (age 9) was the most frequently observed year-class, constituting 29% of the sampled harvest. Average catch rate based on angler interviews was 0.4 fish per hour.
MD DNR biologists continue to tag and release striped bass as part of an interstate, coastal study. Approximately 1,002 striped bass were tagged and released for growth and mortality studies. Anglers encountering a tagged striped bass are asked to help management efforts by reporting the capture of tagged fish by calling the phone number printed on the tag.
MD DNR, Fisheries Service is continuing its voluntary angler survey on the Internet at (www.dnr.state.md.us/fisheries/survey/sbsurveyintro.html for recreational anglers to report their striped bass catch. This survey is designed to obtain important size data on harvested and released striped bass that is not otherwise available to the MD DNR.
Maryland Artificial Reef Program
In 2009, MDDNR-Fisheries Service was able to hire a full-time Artificial Reef coordinator, due to increased license fees and recommendations of the Maryland Fisheries Task Force. This position had not been staffed since 1996. The MDDNR Artificial Reef Program, in partnership with the Maryland Artificial Reef Initiative (MARI) and the Ocean City Reef Foundation (OCRF), is working to enhance finfish and shellfish habitat in Maryland’s tidal bays, tributaries, and ocean waters. The Maryland Artificial Reef Committee (ARC) is an appointed group which advises the Department and the Director of the Fisheries Service on artificial reef (AR) projects. Following the structure of other Atlantic State Artificial Reef Programs, this year in review report summarizes reef program efforts in three major areas: reef site development and construction, monitoring, and outreach with the local fishing community.
Reef Site Development and Construction
The primary reef site development project for 2009 was planning for a shallow water reef at the Down’s Park Fishing pier in Northern Anne Arundel County. MARI is working with a group of students and the head of the science department at Chesapeake Bay Middle School to build a reef composed of reef balls and sea clam shell around the outer portion of the existing public fishing pier. After the permitting process is complete, we hope to begin reef ball construction in April, and deploys the structures in late May or early June.
MARI is also developing new reef sites in the mainstem Chesapeake Bay off Calvert Cliffs, Taylor Island (extension of existing site), upper Tangier Sound, and Hooper Island Straits. Maryland Geological Survey (MGS) has conducted side-scan bottom surveys of these areas, and MDDNR will submit a permit package to MDE and BPW for these four sites.
MARI contributed concrete pavers donated from NSA to the U.S. Army Corps of Engineers and DNR Shellfish Program alternative substrate project in the lower Severn River. The Army Corps contracted with local marine construction companies to transport and deploy the material with clamshell rigs in the Severn, between the Naval Academy Bridge and the Rt. 50 Highway Bridge.
OCRF continued small deployments of reef material at Maryland’s Ocean reef sites. Deployments of retired, stripped down subway cars from the NYC Transit Authority are being phased out. MARI and OCRF are planning to obtain retired vessels, and low profile material, such as concrete, rubble, dredged boulders, and quarry rock for future ocean reef projects.
The tri-state (NJ, DE, MD) project to deploy the retired naval vessel RADFORD at the Del-Jersey-Land Reef Site continued to move forward. The Navy transferred the title of the vessel to DE, and MARI worked on fundraising efforts to support the project.
MARI continued physical and biological monitoring of Chesapeake Bay and Atlantic Ocean Reef sites in 2009. MDDNR and MARI worked under an MOU with Maryland Geological Survey to conduct side-scan surveys of Bay and Ocean reef sites, including the recently deployed NYC subway cars off the Ocean City coastline.
Hook-and-line fishing surveys and diving operations were coordinated with the Maryland Charter Boat Association and also with the Ocean City party boat industry. Preliminary results indicate high densities of black sea bass, bluefish, striped bass, and other finfish species at the reef sites. Divers and biologists were also encouraged by observations of extensive colonies of benthic organisms, marine invertebrates, and shellfish at bay and ocean reef sites.
MDDNR AR program staff and MARI volunteers continued outreach work at fishing club meetings, school group meetings, fishing expos, boat shows, and oyster project open houses. The primary goal of the outreach effort was to inform the fishing and diving community about the MARI program, and also to inform the public on how they can contribute to reef building and monitoring efforts.