Tampa Bay National Estuary Program 

Technical Publication #05-92 

DISTRIBUTION OF SELECTED 

FISH SPECIES IN TAMPA BAY 

FINAL REPORT 

MAY 1992 
#05-92 

DISTRIBUTION OF SELECTED FISH SPECIES 

IN TAMPA BAY 

Prepared for: 

Tampa Bay National Estuary Program 

111 7th Ave. South 

St. Petersburg, FL 33701 

Prepared by: 

Coastal Environmental Services, Inc. 

1099 Winterson Rd., Suite 130 

Linthicum, MD 21090 

Final Report 

May 1992 

Printed on Recycled Paper 
FOREWORD 

This report dated May 1992 and titled "Distribution of Selected Fish Species in 

Tampa Bay" was prepared by Coastal Environmental Services, Inc. for the Tampa 

Bay National Estuary Program. All work was prepared under a contract entered 

into on 16 September 1991 by and between Tampa Bay Regional Planning Council 

on behalf of Tampa Bay National Estuary Program and Coastal Environmental 

Services, Inc. The final products of the project reflect adjustments to the original 

scope of work that were required by the availability of data and time and effort 

considerations. These adjustments have been made in consultation with the 

Tampa Bay National Estuary Program, and are described in a detailed work plan 

submitted on 21 September 1991, and in a revision to the work plan submitted on 

17 January 1992. 

This is Technical Publication #05-92 of the Tampa Bay National Estuary Program. 

I 
ACKNOWLEDGEMENTS 

This project has benefitted from the work of many people, and particularly from 

the willingness of researchers and data managers in the Tampa Bay area to share 

information on their studies. In particular: Dick Eckenrod and Holly Greening of 

the Tampa Bay National Estuary Program provided excellent advice, guidance, and 

assistance throughout the project. Bob McMichael and Tim MacDonald of the 

Marine Research Institute provided data and extensive background information for 

the Fisheries-Independent Monitoring Program, while Ken Haddad provided advice 

and referrals. Thomas Lo of SWFWMD provided the GIS shoreline and 

hydrographic data we used in generating GIS maps. 

ii 

This report was written by Sara Cairns of Coastal, based on work performed by the 

author and Bob Berardo, Peggy Derrick, Doug Heimbuch, Tony Janicki, Susan 

Janicki, John Seibel, and Dave Wade. Special thanks to those whose contributions 

went above and beyond the call of duty. 
ABSTRACT 

Three reports have been generated as products of the Synthesis of Historical 

Biological Data project of the Tampa Bay National Estuary Program (TBNEP): 

"Oligohaline Areas in Tampa Bay Tributaries: Spatial Extent and Species Lists", 

"Database of Benthic Sampling Locations in Tampa Bay", and the current report, 

"Distribution of Selected Fish Species in Tampa Bay". The ten fish species chosen 

for distribution analysis (bay anchovy, silver perch, snook, spotted seatrout, spot, 

tarpon, striped mullet, red drum, hogchoker, and clown goby) were those identified 

by TBNEP as potential living resource targets. The analyses were based on 

extensive spring and fall sampling conducted for the Florida Department of Natural 

Resources' Fisheries-Independent Monitoring Program. An index of relative 

abundance was developed that classified one-minute (latitude by longitude) grids 

within the Bay as having zero catch-per-unit-effort (CPUE), low-to-medium CPUE, 

or high CPUE. Maps based on these analyses were prepared for each combination 

of species, length class, gear, and season for which adequate data were available. 

Several species were shown to concentrate primarily in tributaries during one or 

more seasons, especially small snook and red drum, and hogchokers of all lengths. 

Species with a wide-spread distribution in the Bay with little evidence of seasonal 

change in distribution include bay anchovy and silver perch. 

... 

Ill 
TABLE OF CONTENTS 

Page 

FOREWORD ................................................ i 

ACKNOWLEDGEMENTS ....................................... ii 

ABSTRACT ............................................... iii 

LIST OF TABLES ............................................. v 

LIST OF FIGURES ........................................... vi 

INTRODUCTION ............................................ 1 

METHODS ................................................ 2 

RESULTS ................................................ 4 

DISCUSSION .............................................. 5 

Tarpon .............................................. 5 

Bayanchovy .......................................... 5 

Striped mullet ......................................... 6 

Silver perch .......................................... 6 

Hogchoker ........................................... 7 

Clowngoby .......................................... 7 

Red drum ............................................ 7 

Spotted seatrout ....................................... 8 

Spot ............................................... 6 

Snook .............................................. 9 

SUMMARY ............................................... 9 

REFERENCES .............................................. 49 

IV 

... 
LIST OF TABLES 

Page 

Table 1. Fish species selected for distribution analyses ............... 10 

Table 2. Gear types used in the Fisheries-Independent Monitoring 

Program, and the water depth and bottom type suitable for 

each gear (FMRI 1990) ............................... 11 

Table 3. Length limits used to classify four species of fish as 

juveniles (less than one year of age) ........................ 12 

Table 4. Total number of fish caught by gear and season, all years 

(1989-1991) ....................................... 13
LIST OF FIGURES 

Page 

Figure 1 . Sites sampled by the Fisheries-Independent Monitoring 

Program in 1991, not including fixed stations. ................ 15 

Figure 2. Sampling zones (A-F) and fixed stations (0) used in the 

Fisheries-Independent Monitoring Program. ................. 1 6 

Figure 3. One-minute grids used by the Fisheries-Independent 

Monitoring Program, labelled by zone (A-F). ................. 17 

Figure 4. Bay anchovy relative abundance maps: fish of all lengths 

collected by trawls in the fall and spring seasons. ............. 18 

Figure 5. Bay anchovy relative abundance maps: fish of all lengths 

collected by seines in the fall and spring seasons. ............. 19 

Figure 6. Bay anchovy relative abundance maps: fish of all lengths 

collected by drop nets in the fall and spring seasons. .......... 20 

Figure 7. Striped mullet relative abundance maps: fish < = 178 mm in 

length collected by seines in the fall and spring seasons ........ 21 

Figure 8. Striped mullet relative abundance maps: fish > 178 mm in 

length collected by seines in the fall and spring seasons ........ 22 

Figure 9. Striped mullet relative abundance maps: fish > 178 mm in 

length collected by gill nets in the fall and spring seasons ....... 23 

Figure 10. Silver perch relative abundance maps: fish of all lengths 

collected by trawls in the fall and spring seasons ............. 24 

Figure 11. Silver perch relative abundance maps: fish of all lengths 

collected by seines in the fall and spring seasons ............. 25 

Figure 12. Silver perch relative abundance maps: fish of all lengths collected by drop nets in the fall and spring seasons ........... 26 

Figure 13. Spot relative abundance maps: fish of all lengths collected 

by trawls in the fall and spring seasons ................... .27 

vi 
LIST OF FIGURES (continued) 

Page 

Figure 14. Spot relative abundance maps: fish of all lengths collected 

by seines in the fall and spring seasons ..................... 28 

Figure 15. Spot relative abundance maps: fish of all lengths collected 

by gill nets in the fall and spring seasons .................. .29 

Figure 16. Hogchoker relative abundance maps: fish of all lengths collected 

by trawls in the fall and spring seasons .................... 30 

Figure 17. Hogchoker relative abundance maps: fish of all lengths collected 

by seines in the fall and spring seasons .................... 31 

Figure 18. Clown goby relative abundance maps: fish of all lengths collected 

by trawls in the fall and spring seasons ................... .32 

Figure 19. Clown goby relative abundance maps: fish of all lengths collected 

by seines in the fall and spring seasons ................... .33 

Figure 20. Clown goby relative abundance maps: fish of all lengths collected 

by drop nets in the fall and spring seasons ................ .34 

Figure 21. Red drum relative abundance maps: fish < = 77 mm in length 

collected by seines in the fall and spring seasons ............. 35 

Figure 22. Red drum relative abundance maps: fish < = 77 mm in length 

collected by trawls in the fall and spring seasons ............. 36 

Figure 23. Red drum relative abundance maps: fish < = 77 mm in length 

collected by drop nets in the fall and spring seasons ........... 37 

Figure 24. Red drum relative abundance maps: fish > 77 mm in length 

collected by seines in the fall and spring seasons ............. 38 

Figure 25. Red drum relative abundance maps: fish > 77 mm in length 

collected by gill nets in the fall and spring seasons ............ 39 

Figure 26. Spotted seatrout relative abundance maps: fish < = 170 mm (fall) 

or 230 mm (spring) in length collected by trawls in the fall 

and spring seasons ................................. 40 

vii 
LIST OF FIGURES (continued) 

Page 

Figure 27. Spotted seatrout relative abundance maps: fish < = 170 mm 

(fall) or 230 mm (spring) in length collected by seines in 

the fall and spring seasons ........................... .41 

Figure 28. Spotted seatrout relative abundance maps: fish < = 170 mm 

(fall) or 230 mm (spring) in length collected by drop nets in 

the fall and spring seasons ........................... .42 

Figure 29. Spotted seatrout relative abundance maps: fish > 170 mm 

(fall) or 230 mm (spring) in length collected by trawls in 

the fall and spring seasons ........................... .43 

Figure 30. Spotted seatrout relative abundance maps: fish > 170 mm 

(fall) or 230 mm (spring) in length collected by gill nets 

in the fall and spring seasons .......................... .44 

Figure 31. Snook relative abundance maps: fish < = 150 mm (fall) or 

300 mm (spring)in length collected by seines in the fall and 

spring seasons .................................... .45 

Figure 32. Snook relative abundance maps: fish > 150 mm (fall) or 

300 mm (spring) in length collected by trawls in the falt and 

spring seasons .................................... .46 

Figure 33. Snook relative abundance maps: fish > 150 mm (fall) or 

300 mm (spring) in length collected by seines in the fall and 

spring seasons .................................... .47 

Figure 34. Snook relative abundance maps: fish > 150 mm (fall) or 

300 mm (spring) in length collected by gill nets in the fall 

and spring seasons ................................. .48 

viii 
INTRODUCTION 

The Tampa Bay National Estuary Program (TBNEP) conducted two Framework for 

Characterization workshops in June and July of 1991. One of the conclusions of 

the workshops was that the distribution and historical trends in abundance of fish 

species in Tampa Bay should be priority topics for further investigation. Coastal 

Environmental Services, Inc. focused on these topics as one component of the 

TBNEP's Synthesis of Historical Biological Data project. The other two 

components of the project were the location of oligohaline areas in Tampa Bay 

tributaries (Coastal 1992a) and benthic communities in the Bay (Coastal 1992b). 

In order to analyze trends in fish abundance, it is necessary to have access to data 

that provide reasonable estimates of absolute abundance of a population at 

different points in time. The most extensive data available on Tampa Bay fish 

populations comes from commercial landings statistics collected by the National 

Marine Fisheries Service (NMFS). A recent report (Haddad 1985) used these data 

to analyze trends in two fish populations, but the author noted that commercial 

landings data have major limitations as a source of abundance estimates. The 

specific location where the fish were caught (e.g., within the Bay or offshore) is 

not known, and there is no reliable estimate of the amount of fishing effort. A rise 

or decline in total landings can easily reflect changes in the number of fishermen 

targeting that species, rather than the abundance of the population. 

The NMFS data analyzed by Haddad (1985) indicate that bait shrimp (Penaeus 

duorarum) and spotted seatrout (Cynoscion nebulosus) have declined markedly 

over the period from 1951-1955 to 1981. When trends in landings data are large 

and consistent over time, there is good reason to conclude that populations are 

declining. Unfortunately, non-catastrophic changes in abundance are difficult to 

detect with landings data, being likely to be obscured by changes in fishing effort. 

Historical data on fish populations other than the NMFS commercial landings data 

are also limited in their ability to provide abundance estimates for use in trends 

analysis. Extensive sampling is required to estimate abundance while taking into 

account such factors as shifts in distribution within an area, migration into and out 

of the area, and (especially for juvenile populations) mortality. In addition, 

variations in gear efficiency make it difficult or impossible to combine data from 

different studies. TBNEP decided soon after the start of the Synthesis of Historical 

Biological Data that the available data were not adequate to support analyses of 

long-term trends in fish populations. The focus of the project therefore shifted to 

analyzing current distribution patterns within the Bay. 

An extensive sampling program recently begun by the Florida Department of 

Natural Resources (FDNR), the Fisheries-Independent Monitoring Program, provides 

a source of data on fish distributions that is free of the problems associated with 

1 
commercial landings data. The program is specifically intended to collect data that 

will provide baseline trends and assessments of fish stocks. It targets juvenile 

fishes and uses carefully designed sampling methods and techniques. Although 

not designed specifically for measuring the distribution of fish within the Bay, it 

provides the best available data for this purpose and was selected as the source of 

data for the distribution analyses. 

The ten species of fish identified as potential living resource targets by TBNEP 

were chosen as the subjects for distribution analyses. These are bay anchovy, 

silver perch, snook, spotted seatrout, spot, tarpon, striped mullet, red drum, 

hogchoker, and clown goby (see Table 1 for scientific names). 

METHODS 

Three full years of data were available from the Fisheries-Independent Monitoring 

Program (FIMP), for 1989 to 1991. The FIMP collects data from two types of 

sampling stations: fixed stations and those selected by stratified random sampling 

(FMRI 1990). Fixed stations are sampled monthly, and two types of gear have 

been used consistently across all years: trawls and seines. Random samples are 

collected during two seasons: spring (March-June) and fall (September-December). 

For the random samples, four types of gear have been used consistently across all 

years: trawls, seines, gill nets and drop nets. Each gear type is used only in areas 

appropriate for that gear, as defined by water depth and habitat type (Table 2). 

Within each season, one bay-wide set of samples is collected for each gear during 

the dawn/day time period and one set is collected during the dusk/night period. 

Figure 1 displays the sites actually sampled by each gear type for one year (1991). 

Details on sampling methods are described in the 1989 Annual Report (FMRI 

1 990). 

The sampling area covered by the FIMP is divided into six zones that include Boca 

Ciega Bay, lower Tampa Bay, Old Tampa Bay, Hillsborough Bay, and the lower 

reaches of the Alafia, Little Manatee, and Manatee Rivers. Random sampling 

occurs throughout these zones, while at least two of the 22 fixed stations are 

within each zone (Figure 2). 

The choice of what spatial unit to use in describing fish distributions was an 

important decision in the analyses. The FIMP uses a latitude/longitude grid drawn 

at one-minute intervals to define grid cells used in selecting the randomly stratified 

sampling locations (Figure 3). We decided to use these grid cells as the basic 

spatial unit for distribution analyses. Technically, due to the random sample design 

used in the FIMP, data from individual sampling sites could be used to draw 

inferences regarding abundance for all grid cells suitable for that gear within the 

zone in which the site was located. In practice, we decided (in consultation with 

2 
Dr. Robert McMichael of DNR) that analyses based on zones would result in 

misleading apparent differences between zones. Since zones were defined for 

logistical reasons and not based on habitat differences that would affect fish 

distributions, we decided not to conduct analyses at the level of zones. Analyzing 

the data at the level of grid cells rather than zones had the added advantage of 

allowing us to combine data from the fixed and random sampling programs. 

Since juvenile and adult fish of the same species often have different distributions, 

it was desirable to perform separate analyses for these two age classes. Due to 

natural variations in rates of growth within populations, otolith analysis of 

individual fish is the only reliable method of aging most fish. The FlMP recorded 

lengths for up to 20 fish per sample, but did not age individual fish. We therefore 

used length to infer age. 

For four of the species (snook, spotted seatrout, striped mullet, and red drum) we 

were able to find length limits to use in classifying individual fish as being less than 

or greater than one year of age (Table 3). Within-year variability in growth rates 

for some species (e.g. snook) meant that a more accurate division of different ages 

could be made using different length limits for the fall and spring sampling 

seasons, For six species we did not have length-at-age data based on Gulf of 

Mexico populations, and we combined all catches (regardless of length) to assess 

distribution patterns. 

We restricted analyses to those gears that were deployed in all three years of the 

study (excluding experimental gear types). For each species and age class, we 

also excluded any gear that never caught at least 10 fish in any one year. Samples 

that collected no fish (zero catches) can be used to infer that few or no fish were 

present only if that gear is known to be effective in capturing that size and type of 

fish. By requiring some evidence that a gear type could be effective in collecting a 

given species and age class we increased the probability that observed values of 

zero catch-per-unit-effort (CPUE) reflected low fish abundance rather than poor 

gear efficiency. 

Several different methods (parallel beach set, boat set, and offshore circle set) 

were used to deploy seines in different habitats. Since measures of sampling 

effort (area swept) were available for each, we estimated CPUE separately for each 

deployment method and then treated all seine samples as one gear. 

For each species, age class, gear, year, and season (spring or fall) we calculated 

the average CPUE for each grid cell. Data from the fixed and random sampling 

programs were combined prior to calculating the average CPUE. We used these 

average values (including zeros) to determine the frequency distribution of CPUE 

across all grid cells sampled. We used the 75th percentile of this distribution as a 

cutoff value in classifying individual grid cells as having a 'medium to low' CPUE or 

3 
'high' CPUE. For example, if the average CPUE values ranged from 0 to 15.2, with 

75% of all grid cells having a CPUE value less than 12.8, then only those grid cells 

with an average value greater than 12.8 were classified as 'high'. Grids with zero 

CPUE (no fish ever collected) were assigned an index value of 0, grids with low to 

medium relative CPUE (less than the 75th percentile cutoff) were assigned an 

index value of 1, and grids with high relative CPUE were assigned an index value 

of 2. 

Relative abundance index values were calculated for each grid cell sampled in each 

of the three years. If a grid cell was sampled in more than one year, index values 

were averaged across years. Any average index greater than 0 but less than 1.5 

was given an overall value of 1 (low to medium relative CPUE). (Values less than 

0.5 were not rounded down, so that index values of 0 reflect an absence of 

catches in all years.) Average values between 1.5 and 2 were given an overall 

value of 2 (high relative CPUE). 

It is important to note that these index values reflect relative, rather than absolute 

abundance. In any given season, the total population of a given species and age 

class in the Bay may be either low or high. In either case, these analyses will 

identify those areas (grid cells) with the highest CPUE relative to all grid cells 

sampled that season. In an extreme case, if only 1 fish was collected in one 

season, the grid cell in which it was caught would be classified as having a high 

relative CPUE. Combining data across a three-year period decreases the chance 

that a single sample will determine a grid cell's rank, but due to the random 

sampling design many grid cells were only sampled in one or two of the three 

years. 

RESULTS 

The minute-by-minute (latitude and longitude) grid cells defined by the FlMP were 

the units of analysis for relative abundance, and are also the units used in 

presenting the results. A table of grid cells provides a map of the Bay (see Figure 

3), slightly distorted if the ratio of height to width of a table cell is not the same as 

the ratio of a minute of longitude to a minute of latitude. 

The results of the relative abundance analyses are presented as tables of grid cells 

in Figures 4-34. Each figure presents two maps of Tampa Bay. A separate map is 

shown for each combination of species, length class, gear, and season (with spring 

and fall presented side-by-side on the same page). Unsampled grid cells are left 

blank, cells with zero catches are lightly stippled, and increasing relative abundance 

is indicated by darker shading. 

4 
In addition to grid cell tables for all species, we generated GIS maps of relative 

abundance for two species: red drum (Sciaenops ocellatus) less than 303 mm in 

length in the spring, and snook (Centropomus undecimalis) larger than 150 rnm in 

the fall. These maps have been submitted to TBNEP as one of the final products 

for this project. 

In interpreting the results, greater weight can be attached to maps that are based 

on relatively large numbers of fish captured. Table 4 presents the total number of 

fish caught for each combination of species, length class, gear, and season. These 

numbers do not reflect absolute abundance since sampling effort varied with gear, 

year, and season. They do indicate, for example, that the distribution maps for 

bay anchovy seine and trawl collections are based on large numbers of fish. On 

the other hand, the spring map for bay anchovies collected by drop nets simply 

reflects an apparent absence of bay anchovies in the habitats sampled by dropnets 

rather than a strong concentration of the population in Old Tampa Bay. 

DISCUSSION 

Tarpon (Megalops atlanticus). Tarpon inhabit estuaries and shallow coastal 

waters, spawning offshore but with inshore development of larvae and juveniles 

(Boschung et al. 1983). Their life history within Tampa Bay is not well known, 

and only three tarpon were caught by the FlMP for all gears combined between 

1989 and 1991. Tarpon was the only one of the ten target species for which we 

could not analyze relative abundance. 

Bay anchovy (Anchoa mitchilli). Bay anchovies inhabit shallow bays and estuaries 

(Robins and Ray 1986). This species appears to spawn twice, and sometimes 

three times, a year in the Tampa Bay area (Springer and Woodburn 1960). The 

highest abundance of bay anchovies encountered by Springer and Woodburn 

(1960) was in the late summer and fall. The distribution of this species does not 

appear to be salinity dependent, with specimens collected over a wide range of 

salinities (Springer and Woodburn 1960). 

The wide salinity tolerance of bay anchovies was confirmed by our analyses of 

relative abundance. Bay anchovy were distributed widely throughout the bay in 

both seasons of the year, both in the deep water sampled by trawls (Figure 4) and 

the shallow habitats sampled by seines (Figure 5). The only exception was a 

possible low relative abundance in deep waters near the mouth of the bay during 

spring (Figure 4). Drop nets in seagrass beds (Figure 6) collected few total bay 

anchovies, and those only in Old Tampa Bay. 

5 
Striped mullet (Mugi/ cephalus). Striped mullet spawn from October through May 

on Florida’s west coast (Collins 1985). Juveniles frequent coastal waters, salt 

marshes, and estuaries, during both spring and fall, although some juveniles may 

move offshore in the fall when adults migrate to deeper water to spawn. 

Small striped mullet were collected by the FlMP in large numbers only by seines 

(shallow waters). They were distributed throughout the margins of the bay, 

particularly in the eastern tributaries and Boca Ciega Bay in spring (Figure 7). A 

few larger striped mullet were collected by seines (Figure 8), but gill nets (Figure 9) 

were more effective. They were distributed throughout the bay in the spring, but 

none were collected south of Cockroach Bay during the fall season. These results 

are consistent with those of Springer and Woodburn (1960) who reported that 

striped mullet in the Tampa Bay area occur in all habitats throughout the year, but 

who also reported anecdotal evidence of spawning migrations of larger fish along 

the north shore in the fall. 

Silver perch (Bairdiella chrysoura). The spawning activity of silver perch in Tampa 

Bay begins in June and continues through August. Springer and Woodburn (1960) 

reported that young silver perch appeared in Tampa Bay during the month of June, 

and that the silver perch population in the Bay increased markedly during July, then 

declined until by November very few individuals were being caught. 

The FlMP collected large numbers of silver perch using both trawls and seines. As 

with bay anchovies, there were no apparent concentrations of silver perch in 

particular areas of the Bay (Figures 10 and 11). Drop nets deployed in vegetated 

areas collected very few silver perch during the spring, compared to reasonable 

numbers, distributed throughout the bay, in the fall (Figure 12). 

Spot (Leiostomus xanthurus). Spot spawn from late December through March in 

the Tampa Bay area (Springer and Woodburn 1960). Spawning usually occurs 

offshore either close to bay entrances (Pearson 1929, cited by Springer & 

Woodburn 1960) or in deeper offshore waters (Dawson 1958, cited by Springer & 

Woodburn 1960). Trawl and seine data from previous studies indicate a widely 

distributed population in the spring months (Springer & Woodburn 1960). 

Stomach contents indicate that large spot are bottom feeders (Springer and 

Woodburn 1960). 

Spot were collected in large numbers by trawls and seines, and in moderate 

numbers by gill nets. The deep-water trawl data suggest a possible southern and 

eastern concentration of spot in the fall (Figure 13). Fall seine samples also 

suggest a concentration in the tributaries and the south of the Bay (Figure 14), but 

very few total numbers were captured by seines. Both trawl and seine data 

6 
indicate a widely distributed population in the spring, agreeing with data reported 

in Springer and Woodburn (1960). Gill nets, however, (which probably tend to 

capture larger, older fish than either of the other gears) suggest a concentration of 

fish near the mouth of the Bay in spring (Figure 15). 

Hogchoker (Trinectes maculatus). Hogchokers are a bottom-dwelling species 

commonly inhabiting shallow estuarine areas. In freshwater, they often travel 

hundreds of miles upstream (Robins and Ray 1986). The sizes of the few 

specimens collected by Springer and Woodburn (1 960) suggested that larger 

individuals may be found in more saline waters. 

Hogchokers appeared in large numbers in both trawl and seine collections of the 

FIMP. Both gears indicate that these fish are concentrated in the eastern 

tributaries during the fall (Figures 16 and 17). For the shallow-water habitats 

sampled by seines the eastern tributaries also had high relative abundances in the 

spring (Figure 17), while the deep-water trawls show grid cells with high relative 

abundance throughout the bay in both seasons. 

Clown goby (Microgobius gulosus). Clown gobies inhabit protected, vegetated 

areas with muddy bottoms (Robins and Ray 1986). Springer and Woodburn 

(1 960) documented spawning activity in July and November. 

During the FIMP clown gobies were collected in large numbers by seines, in 

moderate numbers by trawls, and in low numbers by drop nets. Trawls generally 

found low relative abundance in the central part of the bay (Figure 18), while 

seines found patches of high relative abundance throughout the shoreline (Figure 

19). Drop nets also indicated high relative numbers bay-wide (Figure 20). None of 

the three gears suggested any seasonal changes in distribution. 

Red drum (Sciaenops ocellatus). The peak spawning season for red drum in Tampa 

Bay normally occurs from September through October, but has been known to 

occur as early as mid-August (Murphy and Taylor 1990). Pearson (1 929, cited by 

Murphy and Taylor 1990) concluded that spawning typically occurred in nearshore 

waters close to channels and passageways; McMichael and Peters (1 987) recorded 

nearshore spawning as well as spawning in areas at the mouth of Tampa Bay. The 

same authors reported that the majority of red drum larvae exist in the lower Bay 

areas, and that juveniles migrate toward low salinity backwater areas (tributaries) 

of the Bay in the spring months. During sampling from September 1981 through 

November 1983, McMichael and Peters (1987) reported that 98 percent of all 

juveniles caught were collected in tributary areas, with 85 percent coming from the 

Alafia River. 

7 
During the FIMP small red drum were captured in highest numbers by seines, 

though trawls were apparently effective in capturing the smaller fish that occur in 

the fall. Seines recorded areas of high relative abundance in the tributaries in both 

seasons, with scattered high-abundance areas occurring throughout the rest of the 

shoreline (Figure 21). In both seasons, the only areas of high relative abundance 

for the deep-water trawl samples occurred in or near the mouths of the major 

tributaries (Figure 22). Drop nets (fished in vegetated areas) caught no small red 

drum in vegetated areas in the spring, and only a few in the east of the Bay during 

the fall (Figure 23). These results agree with those of McMichael and Peters 

(1987) regarding the concentration of juvenile red drum in tributaries to the Bay. 

Larger red drum were only occasionally captured during the FIMP, by seines and 

gill nets. The fall seine data hint at a concentration in the tributaries (Figure 24), 

but gill net collections in the same season found high relative abundance grid cells 

along the western shore (Figure 25). Gill nets data indicated that larger red drum 

were widely distributed throughout the nearshore areas of the Bay in the spring. 

Spotted seatrout (Cynoscion nebulosus). Spotted seatrout appear to have a 

spawning season that extends from March and April through September and 

October (Mercer 1984, cited by McMichael & Peters 1989). McMichael and Peters 

(1989) concluded that spotted seatrout spawn in middle and lower Tampa Bay, 

with specific spawning areas changing from year to year (depending upon salinity 

and temperature). Juvenile spotted seatrout were commonly found in both 

vegetated seagrass habitats and backwater areas, and appear to be very adaptable 

to different habitat types. McMichael and Peters (1989) suggested that seagrass 

is the primary habitat for juveniles, with 78% of all captured juveniles having been 

collected over seagrass areas. A major long-term decline in commercial catches of 

spotted seatrout may be due in part to loss of seagrass habitat within the Bay 

(Haddad 1985). 

During the FIMP, small spotted seatrout were caught in large numbers by seines, 

moderate numbers by trawls, and low numbers by drop nets. Data from trawls 

showed a scattered distribution in the fall, with low relative abundance in the main 

stem of the Bay in spring (Figure 26). The more abundant seine catches indicated 

possible concentrations near the mouths (saline portions) of tributaries in the fall 

(Figure 27). Distribution in the spring appeared similar to that in the fall, except for 

lower concentrations in the mouth of the Bay and the Manatee River. In general 

these results are consistent with the conclusions of McMichael and Peters (1989). 

If young spotted seatrout are concentrated in seagrass areas, however, the drop 

nets used by FIMP were not very effective at capturing them (Figure 28). 

Larger spotted seatrout were captured during the FIMP in moderate numbers by gill 

nets, and occasionally by trawls. Total captures were too few to put-much 

8 
emphasis on the trawl data (Figure 29). The gear that captured the most fish, gill 

nets, indicates a possible concentration in the lower portion of the main stem of 

the Bay in the fall, with a more scattered distribution in the spring (Figure 30). 

Unlike many of the other species, no high relative abundance of spotted seatrout 

was found inside the tributaries to the Bay. 

Snook (Centropomus undecimalis). Snook spawn between April and December. 

Juvenile snook prefer shallow, protected bodies of water with a small surface area 

(Springer and Woodburn 1960). According to Gilmore et al. (1983, cited in 

McMichael et al. 1989), juvenile snook move from shallow, riverine areas to deeper 

waters of the Bay as they grow. Movements of snook between habitats has also 

been attributed to temperature change (Springer and Woodburn 1960). 

During the FlMP small snook were effectively captured only by seines. These data 

show the best evidence for a very localized distribution among any of the species. 

Relatively large numbers were caught, but almost exclusively within just two of the 

tributaries (the Alafia and Little Manatee Rivers), in both spring and fall (Figure 31). 

These results are consistent with Springer and Woodburn's (1 960) description of 

juvenile habitats. 

Larger snook were captured during the FlMP in low to moderate numbers by each 

of three gears (trawls, seines, and gill nets). The data are relatively scant but tend 

to show a distribution similar to the juveniles, concentrated in the tributaries 

(Figures 32 and 33). The exception is gill net captures in the spring (only 22 fish 

total), which were scattered throughout the nearshore areas of the Bay (Figure 34). 

SUMMARY 

Coastal prepared maps of distribution within Tampa Bay for nine of the 10 species 

idenfified as potential TBNEP living resource targets. The results were typically 

consistent with reported distribution patterns for those species described in the 

literature, while providing an overview for all nine species based on consistent 

sampling methods and effort. A strong pattern of concentration in tributaries was 

found for small snook, indicating the probable importance of habitats within freshwater tributaries as nursery areas for juvenile snook. The highest observed relative 

abundance of small red drum also tended to occur within tributaries, as did that for 

hogchokers of all lengths. In contrast, some species had high relative abundances 

scattered throughout the Bay in both the fall and spring seasons. This was 

particularly true of bay anchovy and silver perch, with the analyses indicating no 

strong habitat preferences or seasonal movements. 

9 
Table 1. Fish species selected for distribution analyses. 

Scientific Name Common Name 

Anchoa mitchilli 

Bairdiella ch ryso ura 

Cen tropomus undecimalis Snook 

Cynoscion nebulosus Spotted seatrout 

Bay anchovy 

Silver perch 

Leiostomus xanthurus 

Megalops a tlan ticus 

spot 

Tarpon 

Trinectes macula tus Hogchoker I 

Mugil cephalus 

Sciaenops ocellatus 

I I Microgobius gulosus Clown goby I 

Striped mullet 

Red drum 

10 






































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