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Discussion Starter · #1 ·
The current diets of striped bass were diverse and usually reflected the spatial and temporal abundance of prey items. Bay anchovy are distributed throughout the Chesapeake Bay and are accessible to most resident striped bass during the year. They contributed to 28% of the numerical and 11% of the total biomass. Bay anchovy were most numerous in the diet during the July-August sampling period. This also coincided with the highest period of the SFI. During this period we observed striped bass actively feeding on bay anchovy near the surface of the water. Most fish collected contained greater than 15 individual bay anchovy in their stomach. Some fish observed contained greater than 30 individual bay anchovy. This was the only time of the year when we collected striped bass feeding on the surface that contained such and abundance of bay anchovy in their stomachs. This may represent the time of the year when bay anchovy are most numerous and available to resident striped bass.

Although menhaden consisted of 3% of the numerical diet, it contributed to almost one half of the total diet biomass. Menhaden contributions to biomass was greatest during the November-December sampling period. We collected many of our larger striped bass (>635mm) during this time many of which had 1 to 2 menhaden greater than 250mm. Young menhaden migrate into the tributaries of the Chesapeake Bay in early May. These young-of-year (YOY) fish are available to striped bass however many fish in our samples in those areas did not contain YOY menhaden from May through mid September.In July and August menhaden contributed to only 0.49% of the biomass. It was during September and October when contributions of menhaden to biomass increased to 39%. MDNR juvenile index for Atlantic menhaden has been declining since 1985. The low abundance of YOY menhaden could be the possible reason for the absence in the diet from May through mid September.In our study mean daily consumption of menhaden for all age groups was consistently less than during 1993.In 1993 menhaden contributions to production ranged from 37-66% whereas during the current study contributions ranged from 12-27%. These differences may be because of the decline in recruitment of menhaden along the Atlantic coast. One may argue whether the decline in menhaden is because of the increase in the total consumption of the increasing striped bass population. Hence striped bass in the Chesapeake Bay have the ability to control their prey abundance. Striped bass are capable of controlling their prey abundance’s in large reservoirs (Moore, 1988). However it is unclear if striped bass can have the same influence on its prey items in the Chesapeake Bay. Although the stripped bass is a top piscviore, other predators rely on menhaden as a source of food (Hartman 1993). Thus the consumption habits of top predators must be considered in assessing the predation on menhaden. Declines in this once abundant prey species of striped bass may lead to shifts towards other nontraditional prey species or directly influence other commercially important species.

Striped bass have been known to consume blue crabs however their full potential influence on the fishery has not been assessed. Hartman 1993 estimated that two million age-2 striped bass annual consumption could equivalent to that harvested in Maryland in 1998.Daily consumption of blue crabs was significantly higher that estimated in 1993. Blue crab consumption by age 1 and 2 was less than one percent.Older fish depended more on blue crabs for production. This increase in consumption could possibly be contributed to the reduction of menhaden available in the Chesapeake Bay. If this is true striped bass could potentially reduce the blue crab population significantly. Spot and Atlantic croaker have traditionally been important to the diets of striped bass (Hollis 1952). MDNR juvenile index survey of those two species have remained constant for the past ten years.We would assume that any shifts in diet would be towards fish such as spot, Atlantic croaker, or other fish species. However these two species were present in very low numbers in our data.

We examined individual consumption and did not make estimates of consumption at the population level. Although estimates of individual consumption are important and may change from year to year, changes in predator populations should show the true influences of predation on prey species. The interest of fishery managers for the Chesapeake Bay is the effect of the increased striped bass population on fish species.

Striped bass diets, growth, predation, and consumption are influenced by changes in the density of striped bass, which may influence the relative abundance and composition of the prey fish community. The predatory affect of striped bass in the Chesapeake Bay Estuary in unclear. We hope to provide information leading to a better understanding of the role of striped bass in the Chesapeake Bay. These estimates will allow managers to more effectively deal with other resource user groups and provide reliable estimates of the results of management decisions for striped bass on other Bay resources.

Input data for bioenergetic models are important to the accuracy of the output of the model. We also used an age-length key to age our fish. True readings of age are needed to increase the accuracy of the consumption estimates on the cohort level. The use of an age-length key may have led to the minimal differences in consumption as a function of temperature observed in ages 2-4. The completion of the aging of striped bass will allow us to estimate the predation of striped bass to quantify the predatory demand more accurately at the individual, cohort, and population level.

Historical Profile of Striped Bass Feeding Habits in the Chesapeake Bay

During the period from 1955 through 1959 bay anchovy and Atlantic menhaden dominated the diet of striped bass. These two species contributed equally to the diet during this period.We have not been able to collect the desired amount of food habit data on striped bass from 1960-1970.However to complete this we will be contacting other sources for information specific to the diets of striped bass for inclusion into the bioenergetics model.



Relationship Between Skin Sores on Striped Bass and Condition

There is general agreement that systemic microbial infections in fish, particularly bacteria, lead to a combination of weight loss and the appearance of sores on the skin (Ferguson 1990; Roberts 1989; May and Sindermann 1999).What is not understood is why since 1994 there has been the repeated seasonal appearance of sores on striped bass.Early diagnostic work implicated E. tarda as the primary agent responsible for the condition (Baya, et al. 1997). A variety of bacteria have been isolated from striped bass exhibiting skin sores since 1997 (MDNR, 1998). The data from this study would suggest that at least 15% of the fish taken exhibited sores that were the result of non-mycobacterial infection.

From 1997 to the present the focus has been on Mycobacterium sp. because it has been this group of bacteria that have been consistently isolated from striped bass resident to the Chesapeake Bay.Mycobacterium sp. are acid fast bacteria belonging to the Mycobacteriaceae family.Characteristics of this group are that they are slow growing and extremely fastidious when cultured, making them difficult at best to isolate and identify (Frerichs 1993). Several members of the group have been found to infect fish, M. marinum, M. fortuitum, and M. chelonae (Frerichs 1993). More recent work by the Virginia Institute of Marine Science (VIMS) has shown that possibly 7 species could be involved, greatly complicating the picture (Vogelbiem et al., 1999).

Experimental evidence with mycobacterial infections has repeatedly shown that once infections are established, they are progressive leading to emaciation, appearance of sores, and ultimately death (Reimschuessel, 1997). The only experience with wild striped bass infected with Mycobacteria sp. was in the late 1980’s involving resident populations in the San Fransisco Harbor area (Sakanari et al. 1983), our understanding of how this genus of bacteria will affect striped bass in the wild is very poor. The wide spread distribution of the condition in striped bass since 1997 did, however, lead fishery managers to consider the possibility that the skin lesions were the consequence of infections which were brought on by the lack of available prey. This possibility was considered based on the number of emaciated appearing striped bass and the apparent relation between emaciation and the appearance of sores.

This phase of the study was designed to answer those questions which would be of importance to fishery managers in understanding what the potential influences of this condition are, and they are: (1) what is the degree to which the population is affected by either the infective agent, condition or both; (2) which came first, the infection or starvation what will be the final outcome of the infection or condition (will the fish survive) and (3) what will be the final outcome of the infection or condition (will the fish survive).

The incidence of sores from the fish taken during 1998 and 1999 was nearly 50%, of which 15% were represented by striped bass exhibiting sores for which the cause could not be attributed to mycobacteria. Fifty three percent of the striped bass taken in 1998 and 1999 had granulomas attributable to mycobacteria in one or more organs.This suggest an extremely high rate of infection. This rate is consistent with that seen in California and Oregon Waters in the early 1980’s with 25-68% infection in California, the highest in the San Francisco Bay area, and 46% in Oregon Water (Sakanari et. al. 1983).

Experimental work in the past has shown that otherwise healthy goldfish, when injected with Mycobacteria sp., will exhibit a progressively debilitating disease with death the ultimate outcome (Reimschuessel 1997). Similarly naturally infected populations of yellow perch, cod, farm-raised turbot and flounder exhibited the same progression with emaciation and death the outcome (Dalsgaard, et al. 1992; Daust, et al. 1989; Lama, et al. 1996; Vethaak and Jol 1996). The outbreak in San Francisco Harbor area was intensively studied but the final conclusions were not able to suggest that the affected fish died even though the authors felt that the condition would probably lead to death (Sakarnari et al. 1983).The results presented from this study to confirm the experimental work and the inferences of Sakanari et. al. (1983) that death is the outcome after mycobaterial infections.The condition becomes systemic and the bacteria appear primarily in the head kidney and spleen.When legal and sublegal individuals are compared there is a significantly higher level of splenic involvement, suggesting an age dependency. This is supported by a lower condition factor among legal fish as compared with sublegal, and the higher incidence of fish with both granulomas and sores among the legal sized striped bass. If comparisons are considered between the NGNS, GNS, and GS categories the trend is toward a significantly lower condition factor in the GS category as compared with NGNS and GNS categories. In legal fish this difference is not as apparent as in the sublegal fish.

General Relationships

It is clear from this work that bioenergetics is a useful tool in identifying changes in predator prey relationships, particularly when adequate benchmarks are available. Comparisons of results from the study by Hartman (1993) and those from this study indicate changes. Limitations do exist, particularly in addressing populations with extraordinary rates of infection by bacterial pathogens. Healthy fish were defined by the absence of granulomas and sores should be used for final assessments. The bioenergetics model used in this study did not take infections into account. Future analyses will be conducted to identify changes in the growth rates based on age data.The age data, when coupled with infection intensity may indicate how Mycobacterium sp. alter growth rates. This information will help eliminate the individuals used as part of the data base for the bioenergetics model.

The usefulness of diet studies, which are the basis of the bioenergetics model is underscored by the fact that if there has been a shift in prey for the striped bass populations resident to the Chesapeake Bay, then logically there will have been shifts in the types of micro and macro nutrients available.It is strongly suggested that emaciation among striped bass is because of the disease process, the condition(s) which result in an increased predilection of striped bass for becoming infected with Mycobacterium sp. may lie with altered diets. It is well know that nutritional shifts have deleterious effects on fish, and in many situations affect the immune status (Steffens 1989). This is not to say that this is the only possible cause for the condition, but is one of many possible origins of ulcerative dermatitis in striped bass.

Our assumption that the disease is progressive ( Figure 15) is in part based on the conceptual model of granulomatous inflammation by Adams (1983) and modified by Sindermann (1999) which suggests that there are three possible outcomes; resolution, mature granulomas, or death (Sindermann 1999).From our data and the model presented by Sindermann (1999), we would suggest that mycobacterial infections of striped bass begin in the Chesapeake Bay estuary and from the moment of infection progresses until death occurs in a large portion of the resident striped bass. From the fish taken during some of the age 1 and many of the age 2 fish were confirmed to have mycobacterial infections. Older fish were infected, and scale analyses will show how many of these fish were infected and to what intensity.



Figure 15.




The ultimate repercussions of the disease process caused by Mycobacterium sp. and diet shifts on striped bass populations can only be inferred at this time. The disease process may be initiated at different ages in the striped bass, hence the life span after infection will differ. This would result in a slow cropping of infected individuals which die and are scavenged or debilitated and easily eaten by predators. In either situation mass mortalities would not be more obvious.The influence of mycobacterial infections should be seen in recruitment, with natural mortality rates greatly increased and survival to reproductive age decreased. Dietary shifts may have much broader effects with changes in prey species abundance, lack of proper development in young striped bass, lack of proper gonadal development, and increased susceptibility to a broad array of viral, bacterial, fungal, or metazoan pathogens.




Conclusion



It seems that the shifts in the feeding habits of striped bass have occurred since 1993.This coincides with a steady increase in the striped bass abundance and slow decrease in the abundance of traditional prey items. However it is not clear whether these shifts are due to the increase in demand and consumption by striped bass, environmental changes, or by anthropogenic factors. The repercussions of these shifts may be to adversely affect the health of the striped bass by limiting the amount of energy available through this tropic pathway. Alternatively, the effect may be by a direct increase in the consumption of the other fish species impacting both striped bass and other fish production in the Chesapeake Bay.We do show evidence of an increase in the occurrence of external lesions in the striped bass population and also an increase in bacteria, which seems to cause a decrease in the overall health of striped bass. It is not clear whether the changes in the feeding habits of striped bass have caused individuals to become more susceptible to certain bacteria, but we hypothesize that there is a strong correlation between the two.
 

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Discussion Starter · #4 ·
For those of you that think that big striper do not depend on menhaden

For those of you that think that big striper do not depend on menhaden

Give it up.
 

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This year for the first time in 10 Years we saw Menhaden back in the Ct. River. Every Menhaden we took out to the local reefs got sucked up by a 40" plus Striper...

BIG BAIT EQUAL BIG BASS!!

In Boston when the Mackerel and Pollock move north the Big Bass follow... They head up to NH until the fall... I think the Boston Stripers come form the VA heard and the CT/LI Sound Stripers are Hudson fish...

We have not seen Bunker in Boston in 15 years!
 

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Discussion Starter · #7 ·
this is not about conservation but information that helps fisherman

Eduacate yourself and you will be set free.

LOL
 

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Excellent post and very informative. Are you part of these stiudies or is this secnd hand info? Either way, thanks for sharing.
 

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I support you COMPLETELY --- Where did the study info originate? How can we pound this info into the ASMFC people??
 

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Other fish ......

You know, I have cleaned my share of fish this year between mating on several charter boats and personal fishing time and it seems I have seen some variation in the overall diet....depending upon the time of the year.....early spring, mostly menhaden and anchovies...silver sides....glass minnows......early fall....menhaden..anchovies...silversides....spot..... crab....LARGE shrimp....fall and now.....EELS EELS EELS and a few menhaden....
 

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Discussion Starter · #11 ·
In the bigger fish when we clean them you mostly see menhaden

In the bigger fish when we clean them you mostly see menhaden. Whe run a charter boat out of Rudee Inlet the Salty Hooker. We have seen batteries and crazy stuff like that but mostly menhaden.

Salty Hooker Sportfishing
 

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Too many could be's and maybe's for me to put alot of "fact" to what ya posted.

But, it's all in what ya think and how one wants to interpet information.

For 5 mins., I thought I was on the Conservation and Policy board.
 

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Discussion Starter · #14 ·
I am part of the Atlantic Slatwater Expeditions team

We have a charter Boat out rudee inlet called the Salty Hooker. We have done a lot of our own research and worked with various groups that study this information. I for one want to keep fishing well into my retirement and this is one way can do it. Please do not guess at things you love study them and become more efficient and a better stewart.

Salty Hooker Sport fishing Team.

See you at the rockfish Shootout i wonder if they would going ahead and putting salty hooker II on the contender ahead of time. Just kiddin.
 

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Please list references as to where this info is published. Who are you financial supporters and are you affiliated with any educational institution and or credible research firm.

I ask this because you may be eligible for a grant for the license money fund.
 

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Quick Google search.

http://www.chesbay.org/articles/2.asp

This is a Cooperative Program of the​
U.S. Geological Survey​
Maryland Department of Natural Resources​
University of Maryland Eastern Shore​
U.S. Fish and Wildlife Service​
Wildlife Management Institute​
 

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How many of you would let a Doctor start a chemo and radation program because your symptons "could be" caused by cancer?

How many of you would let a mechanic rebuild your motor because "maybe" it needs to be rebuilt?

See where I am going here?

The GA agrees that there "MAYBE" a problem with the menhaden population.

They placed a cap on the harvest until further studies are complete.

At this point, the GA has done exactly what it should have done.
 

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Thanks

Thanks for the posts Capt Jake. I am with you as far as doing my part in the BIG scheme of things. The links you put up are helpful. Good Luck in the Shoot Out!
 
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